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PALAEONTOGRAPHICA
AMERICANA
VOW
1965-1967
PALEONTOLOGICAL RESEARCH INSTITUTION
a a
PALAEONTOGRAPHICA
~ AMERICANA
Volume V
No. 34
1965
PALEONTOLOGICAL RESEARCH INSTITUTION
1964 - 1965
PRESIDENT 2.52205 5002 vos. ceew cevascasc occeweaes res savant ot Ss canescece cncaat es Reena AXEL A. OLsson
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DIRECTOR: siccavecsesvescsssssesascvattazisessvsssoedecevassactecteeviossecastaceszives KATHERINE V. W. PALMER
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REPRESENTATIVE AAAS COUNCIL KENNETH E, CASTER
Trustees
KENNETH E. CAsTER (1960-1966) KATHERINE V. W. Paver (Life)
Donato W. FisHER (1961-1967) WituiaM B. Heroy (1963-1968)
Resecca S. Harris (Life) AXEL A. OLsson (Life)
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W. Storrs CoLe (1964-1970)
BULLETINS OF AMERICAN PALEONTOLOGY
and
PALAEONTOGRAPHICA AMERICANA
KATHERINE V. W. PALMER, Editor
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Advisory Board
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PALAEONTOGRAPHICA AMERICANA
(Founded 1917)
NO. 34
UPPER TERTIARY ARCACEA OF THE
MID-ATLANTIC COASTAL PLAIN
By
SAMUEL O. Birp
Mary Washington College
of the University of Virginia
March 22, 1965
Paleontological Research Institution
Ithaca, New York, U.S.A.
Library of Congress Catalog Card Number: GS 65-1
Printed in United States of America
Norton Printing Company
TABLE OF CONTENTS
Abstract
Introduction. ....... 5
Acknowledgments _.............. 5
Previous work on the arcids 5
Procedure 6
Upper Tertiary stratigraphy of Maryland, Virginia, and
North Carolina 7
Lower Miocene ............ 7
Middle and upper Miocene 7
Upper Miocene ......... 8
Yorktown formation 8
Duplin marl ........ 9
Pliocene 9
Waccamaw formation 9
Croatan sand m9),
IBEN DY (oh UL eeonteao Stee csch ep acc cO Nec Ocoee SCE Oe ee le eee = 0
Register of localities ... rem_1U(0)
Localities not included 10
Geologic history 5 I)
Ecology and stratigraphic relations .. 5 oll
Discussion 5 itil
Findings 5 ill
Conclusions 16
Glossary of statistical terms 18
Equations for statistical analysis .... 18
Quantitative morphologic features and significance levels 19
Systematic paleontology
Nuculidae
Nucula ..
Nuculanidae .
Nuculana ..
Key to upper Tertiary arcids of Mid-Atlantic Coastal Plain ....
Arcopsis .
Striarca
Anadara .....
Cunearca
Lunarca
Noetia ......
Eontia
Glycymeridae
Glycymeris
epee SiSterem Ohm lOCAalities meres csc-mteiesse sts an oetet ene tmeee ee
2. Gastropoda and Pelecypoda species from localities in Table 1 ....
3. Typicality ratings from Matrix 1
+. Clusters formed from analysis of Matrix 1 =
5. Abundance chart of Foraminifera genera from localities in Table I ....
6. Species used for statistical analysis of arcids
7. Typicality ratings of arcid species from Matrix 2 . 24
Sa Clictersietocmedmb yaranallysis¢ ofan! Va trixey 2 eee meee eee 24
9. Comparisons of regression coefficients in Anadara ... 30
10. Comparisons of regression coefficients in Noctia ... . 38
11. Comparisons of regression coefficients in Glycymeris . . 42
Appendix
Tables 12,
ng Waa.
iivalblesml4asii9Ssec AT
AIA D1ESE 2 0= 2S eam ercneeecer se ctce ec ee ca ari see e e ee n eee 48
NADL ESH2 623 lie wreck seer ncerect ee eee ere ne NY ee ay er etna ee 49
Tables > SM
Tables 51
MATRIX
..between 16-17
1. Match coefficients for localities in Table 1 é
....between 22-23
2. Match coefficients for 30 arcid species in Table 6 .......
UPPER TERTIARY ARCACEA OF THE MID-
ATLANTIC COASTAL PLAIN
SAMUEL Oscar Birp
ABSTRACT
An attempt is made to establish the unifying characters of many
supraspecific categories of the arcid pelecypods. The diverse Arcidae
is typified by subrhomboidal valves, sublinear dental plates, and lat-
eral teeth perpendicular or highly oblique to the hinge line. The sub-
family Arcinae may be characterized by round, superficial, sinuous
ribs, and an absence or near absence of crenulations; the Anadarinae
by flat, well-formed costae and crenulations; the Noetiinae by well-
formed crenulations and ribs, riblets in the interspaces, and distinct
vertically striated ligamental area. The family Glycymeridae is char-
acterized by suborbicular valves, lateral teeth that are subparallel
to the hinge, and prominent crenulations.
Some representative genera and subgenera are analyzed statisti-
cally on characters including the ones mentioned above. The resultant
grouping of the genera and subgenera produces a classification
similar to that of Reinhart (1935, 1943). Several subgenera are put
into synonymy as a result of the study.
Species are diagnosed and figured. Selected species are studied
quantitatively to help standardize the nomenclature and to establish
evolutionary trends and systematic relationships.
Stratigraphic relations in the upper Tertiary of Virginia and
North Carolina have been ascertained previously on gross aspects of
faunas with inadequate evidence for proposed relations. However,
statistical analysis of large collections supports much of the pre-
viously established correlation. In the analysis, all identifiable gas-
tropod and pelecypod species from each of 22 localities are recorded
and analyzed by the Rogers and Tanimoto method (1960) which is
here applied to a geologic problem for the first time. In this manner
the Yorktown formation along the Chowan River in North Carolina
is shown to be approximately equivalent in age to the Duplin marl. A
sample from the type Yorktown and its correlatives in Virginia and
North Carolina are relatively older than the Duplin marl and the
portion of the Yorktown equivalent to it as shown by the clustering
and by the mean percent of gastropod and pelecypod species ranging
to the Recent in these respective clusters. Correlation of the Croatan
sand and the Waccamaw formation is supported, and the mean per-
cent (60%) of gastropod and pelecypod species ranging to the Re-
cent indicates a lower Pliocene age for these beds.
INTRODUCTION
This study was undertaken to make the arcid pelecy-
pods of the upper Tertiary of North Carolina and Virginia
better known and to establish, if possible, systematic rela-
tionships between species. Bivariate studies of populations
were made to help determine these relations and to find if
stratigraphic or geographic trends could be found. Repre-
sentative species of arcids were compared by the Rogers-
Tanimoto method of multivariate analysis (1960) to de-
termine affinities between genera and subgenera and to
statistically test the validity of some previously proposed
supraspecific categories.
The relative ages of the deposits were also studied
quantitatively by application of the Rogers-Tanimoto
method, which has general application to geologic prob-
lems, though the method was originally applied to plant
taxonomy and classification. Localities studied were divided
into major groups based on multivariate analyses and the
mean number of gastropod and pelecypod species ranging
to the Recent in each of these groups was calculated.
ACKNOWLEDGMENTS
Drs. Joseph St. Jean, Jr. and W. H. Wheeler, the
writer’s major advisors, contributed to this study with their
suggestions and criticisms. Prof. St. Jean helped particularly
with the statistical approach, thin section analyses, zoo-
logical nomenclature, and foraminiferal analyses; Prof.
Wheeler aided with his experience and knowledge of
faunas, localities, and stratigraphy of the area. A portion of
a University of North Carolina Alumni Research Fund
Grant to Dr. Wheeler was made available to me by Dr.
Wheeler for assistance to him in the field. This aid, which
defrayed much of the field expenses, is greatly appreciated.
The National Science Foundation also helped with finances
as did the University of North Carolina (by way of an
assistantship and the Smith Fund). Druid Wilson of the
U. S. Geological Survey kindly shared some of his knowl-
edge of the stratigraphy of the Silverdale, North Carolina,
area and made Tertiary and arcid collections at the U. S.
National Museum available for examination. The friendly
conversations and exchange of opinions with graduate stu-
dents at the University of North Caroina is also appreci-
ated. The writer wishes to acknowledge aid from his wife,
who helped with the typing, and who lent moral support
throughout the study. Thanks are due Mary Washington
College for defraying the cost of the engraving of the illus-
trations.
PREVIOUS WORK ON THE ARCIDS
The genus Arca was erected by Linné in 1758. The
name was applied to many prionodonts and some nuculoids
during the 19th Century and in a few cases in the 20th Cen-
tury. Lamarck (1818, 1819, 1835) erected the Arcacées and
recognized features of the family. He included four genera
in the group: Cucullaca, Arca, “Pectunculus,” and Nucula.
Gray (1840) published a series of nomina nuda in The
Synopsis of the Contents of the British Musewm, which
included genera of arcids used in more recent works.
In 1842, 1847, Gray validated his names of 1840 by publish-
ing types for his genera and subgenera and in 1857 gave a
classification and brief description of arcids. All genera and
subgenera included in the 1857 paper were referred to the
family Arcidae which was subdivided into two tribes: the
Arcaina and the Pectunculina. The Arcaina included the
more typical arcids and the Pectunculina included Pectwn-
culus (i.e. Glycymeris) and Limopsis. Both of these genera
are now in separate families of the Arcacea.
Additional genera and subgenera of the Arcacea, the
6 PALAEONTOGRAPHICA AMERICANA (V, 51)
term employed by Lamarck (1818) and most subsequent
workers for the group, have been added since Gray's ume.
One of the most prolific workers was Conrad, who pub-
lished important works in which arcids were described:
1840, 1845, 1863, and 1875.
Dall (1895, 1898) employed the term Arcacea as a
superfamily including the Parallelodontidae, Limopsidae,
and the Arcidae as families. The Arcidae was divided into
two subfamilies by Dall (1898): Pectunculinae for Glycy-
meris and Arcinae for the more typical arcids. Some of the
genera and subgenera of the Arcinae were subdivided into
sections and groups, and an attempt to establish synonyms
for supraspecific categories was made by Dall.
A classification of the arcids was presented by Reinhart
in 1935. His paper did not include diagnoses of families and
subfamilies nor were genera and subgenera defined formal-
ly, though the main features of some forms were given. ‘The
value of this work comes from the grouping of forms into
families and subfamilies. Reinhart’s 1943 paper on the
Tertiary Arcidae of the Pacific slope of North America is
paralleled by Sheldon’s (1916) less ambitious work on the
East Coast arcids. Sheldon followed the classification of Dall
(1898) but omitted the glycymerids.
In 1938 MacNeil made intensive studies of the noetid
arcids and erected the family Noetiidae for the group. ‘The
affinity between some members of the proposed family is
obscure. Reinhart (1943, p. 76) deleted some forms put
into the Noetiidae by MacNeil. As a result of the present
study, the proposed family seems too artificial to be useful,
more members are deleted, and a subfamily status is re-
tained for the remaining forms.
Other important works in which species of the ‘Tertiary
of the Atlantic Coastal Plain are made known are those of
the Florida faunas by Mansfield (1932, 1937) and by Gard-
ner (1943) who worked with the Mid-Atlantic Coastal
Plain specifically.
Some important, more general works are by: Nicol
(1945, 1950, 1953) who studied the glycymerids, attempted
to establish their ancestry and evolutionary trends, and who
studied the cuculleaids (1950a, 1954): Arkell (1930) at-
tempted to ascertain the phylogeny of some Jurassic arcids;
and Newell (1937, pp. 27-30; 1942, p. 25) investigated the
ligaments of the arcids. Bggeild (1950) studied shell mor-
phology of the Mollusca and included a section on the
arcids. From my studies of thin sections on a few representa-
tives of the group, it appears that the Arcacea may lend
themselves well to studies of this type and perhaps the
classification of the group could be strengthened by thin
section analysis.
Soft-part studies of the arcids have been largely
neglected. An important work is that of Heath (1941)
which included some gross soft-part morphology (more of
this kind of observation is needed) . Heath made a detailed
study of muscles of the visceral area and included a bibliog-
raphy in which some previous zoologic studies (largely on
the circulatory system) are noted. More recently Rost
(1955) made a less intensive study of the soft-part mor-
phology; again minor structures are stressed and little is
reported on major features such as the nature of the byssus,
adductor and pedal musculature and ligament.
Keen (1958) attempted to summarize the distinguish-
ing features of the common arcid genera and subgenera of
the Pacific Coast and in so doing produced a good reference
for an understanding of the group.
The ecology of the Arcacea is essentially unknown or
at least unpublished.
The stratigraphic investigations of the Mid-Atlantic
Coastal Plain have been summarized by Pratt (1941).
Gardner (1943), and to some extent McLean (1956).
PROCEDURE
To judge the taxonomic value and systematic relations
of genera and subgenera of arcids and to help with strati-
graphic interpretations, statistical analyses are made follow-
ing the method of Rogers and ‘Tanimoto (1960). This
method, which was originally designed for use in plant
taxonomy, is here applied to geologic problems for the first
time. The Rogers ‘Tanimoto technique is based on princi-
ples of Information ‘Theory! and the inverted factor tech-
nique or Q-method of Stephenson (1936). The inverted
factor involves the accumulation of qualitative and quanti-
tative data or both from an individual or group of indi-
viduals. Individuals instead of quantitative characters of in-
dividuals (the more conventional method in paleontology)
are correlated.
Both the conventional method of analysis and the
Q-technique are used in the course of study. In the con-
ventional method (R-technique of psychology) information
is gathered on a series of individuals of two or more popula-
tions. Data consist of measurements of characters such as
height and length. Correlation coefficients or regression
equations are calculated for combinations of any two char-
acters at a time for each sample. ‘Two samples are then
compared in the typical bivariate manner using a t-test to
test the relation of two characters from one sample to the
same two characters of another sample. A multivariate
'For introduction to Information Theory see Yockey, 1956.
Mip-AtTLANTIC “VERTIARY
analysis for quantitative characters has been devised by
Olson and Miller (1958). This method also employs a char-
acter to character correlation. In the present study, bivari-
ate analysis is used on species when quantitative data are
readily available and distinction of two or more species is
to be tested.
In the second type of test (Q-technique) , which is used
here to test relations of supraspecific categories and strati-
graphic horizons qualitative and quantitative information
can be combined. For taxonomic study, many characters are
observed and measured on an individual or a group of indi-
viduals. Numbers of characters ‘are divided into categories
such as shape or class intervals. The greater the number of
matches between individuals, the greater the relationship
between the entities compared. For stratigraphic correlation
study, species are treated as attributes of genera and the
degree of relationship is determined by the number of
species in common between the localities being compared.
The method of arriving at the degree of relationship
is different in the Sokal and Michener (1957, which is also
based on the Q-technique) and the Rogers- Tanimoto meth-
ods. In the analysis derived by Sokal and Michener, corre-
lation coefficients are calculated whereas in the Rogers-
‘Tanimoto analysis a ratio of the number of matches to the
number of misses is calculated. The method of determining
clusters is also different in the two methods.
In this study, the term match coefficient is used instead
ol s,; (see Glossary of Statistical terms), and matrices and
typicality ratings are presented without the inverse of the
log, (d;,) being taken so that these tables can be read more
easily. Accordingly, the larger the value of a match coeffi-
cient, the greater the relationship of those individuals or
cases compared. Similarly, the greater the sum of rows and
columns, the greater the typicality rating. This is the in-
verse of the way information is presented in the paper by
Rogers and ‘Tanimoto; otherwise the analysis is the same.
UPPER TERTIARY STRATIGRAPHY OF
MARYLAND, VIRGINIA, AND NORTH CAROLINA
LOWER MIOCENE
‘The beds at Haywood Landing and Silverdale, North
Carolina, (see register of localities) are considered lowei
Miocene by Druid Wilson
Kellum (1926, pp. 12-14) correlated the deposits at Silver-
(oral communication, 1961).
dale with the Tampa formation of Florida. This correla-
tion was supported by Mansfield (1937, pp. 18, 19). Wil-
son discovered an outcrop at Haywood Landing and corre-
lated these with beds at Silverdale. The relation of the
Haywood Landing deposits and those at Silverdale to the
ARCACEA: BirRD if
Trent formation, which has been referred to the upper
Eocene (Miller im Clark, Miller, et al., 1912a, p. 174) and
to the lower Miocene (Kellum, loc. cit.) , will be discussed
by P. M. Brown and Druid Wilson in a paper in prepara-
tion.
The lithology of the lower Miocene strata in the
Silverdale area is gray sand with some clay and many
fossils. Anadara (Anadara) siluverdalensis (Kellum), 1926
and Glycymeris anteparilis Kellum, 1926 are common and
characteristic lower Miocene fossils of these localities.
MIDDLE AND UPPER MIOCENE
The Chesapeake group in Maryland and Virginia
constitutes the surface exposures of the basal middle Mio-
cene in the area of discussion. The formations are the Cal-
vert, Choptank, and the St. Marys. ‘The sediment consists of
clay, sandy clay, sandy marl, and diatomite.
Calvert formation.—The type locality is Calvert cliffs
along the west shore of Chesapeake Bay, Calvert County, in
Maryland. The cliffs are 100 feet high and extend 20 miles
from Drum Point to Chesapeake Beach. The complete
thickness of the beds has nowhere been observed (Shattuck
im Clark, et al., 1904, p. Ixxi). The Calvert formation is
truncated above by the Choptank and other younger for-
mations. Based on well records in Somerset County (south-
eastern part of Maryland) the thickness is 500 feet (Shat-
tuck, op. cit., pp. Ixx-Ixxii).. A sample of Glycymeris parilis
(Conrad) , 1842, a characteristic Calvert fossil, from Plum
Point, Maryland, is studied later in this paper.
The Calvert formation extends into Virginia as far
south as Petersburg in Prince George County (Mansfield
im Gardner, 1943, p. 5). The lithology of the formation in
Virginia is essentially the same as in Maryland.
Choptank formation.—Vhe type locality is on the north
bank of the Choptank estuary just below Dover Bridge,
Talbot County, in Maryland. The formation les un-
conformably above the Calvert formation. The thickness is
variable; in the well in Somerset County it 1s 175 feet which
is in excess of any surface exposure (Shattuck, op. cit., pp.
Ixxvili-Ixxx). The lithology is a fine yellow quartz sand,
sandy clay, and in places ledges of indurated sandstone
occur. No Choptank fossils are dealt with in this report.
The Choptank formation is known in Virginia from
only two localities. It apparently extends as far south as the
Rappahannock River in Virginia, where it thins and disap-
pears.
Calvert and Choptank equivalents? have been reported
2These deposits have been called the Pungo River formation by
Kimrey (1964).
8 PALAEKONTOGRAPHICA AMERICANA (V, 31)
from the subsurface of several counties in North Carolina
by Brown (1958). Their lithology, from well samples,
has been found to be brown, phosphatic sand, and sandy
silt, with collophane averaging 30% but reaching as high
as 90% (Brown, op. cit., Table 1).
St. Marys formation.—The type locality is at St. Marys
City on the St. Marys River, St. Marys County, Maryland.
The formation has not been reported from the east shore
of Chesapeake Bay but is present in southern Calvert and
southern St. Marys Counties. The lithology is clay, sand and
sandy clay with some beds locally indurated by iron cement.
The beds rest unconformably on those of the Choptank
formation (Shattuck, 1904, pp. Ixxxii-lxxxv) . According to
Shattuck (op. cit., p. Ixxxiv) , the thickness of the formation
is 280 feet in Somerset County. According to Cooke, et al.
(1943, p. 1724), the St. Marys is both middle and upper
Miocene.
The St. Marys formation extends as far south as Isle of
Wight, Southampton, and Nansemond Counties in south-
ern Virginia where exposures occur along the Nottoway
and Blackwater Rivers (Clark and Miller, 1912, p. 142).
The deposits are similar to those of Maryland; locally glau-
conite is common. South of the Meherrin River, also in
southern Virginia, the St. Marys is not well exposed. ‘The
beds is this area consist of yellow to blue fossiliferous sand.
Along the Meherrin River, near Emporia in Greensville
County about 35 feet of greenish gray clay with molds of
fossils has been referred to the St. Marys (Clark and Miller,
op. cit., p. 155). In Virginia, the St. Marys overlies the Cal-
vert unconformably except in Sussex, Greensville, and
Southampton Counties, where it rests on crystallines.
According to Mansfield (7m Gardner, 1943, p. 11), the
St. Marys has been doubtfully recognized in the northern
part of North Carolina. The formation has not been
definitely recognized from the subsurface.
Sections showing lithology, fossils, and zonation of the
Chesapeake group in Maryland are given in Shattuck,
(1904, pp. Ixxxvi-xc) .
UPPER MIOCENE
Yorktown formation.—The type locality is the bluff at
Yorktown on the York River in Virginia. The formation
(named by Clark and Miller, 1906, p. 19) has been divided
into two faunal zones (Mansfield, op. cit., pp. 7-13). The
lower, zone 1, consists largely of medium-egrained gray to
bluff sands which rest uncomformably on the St. Marys for-
mation. According to Mansfield, this zone is exposed at
Bellefield about four miles west of Yorktown, York County,
on the south bank of the York River, and at Kings Mill
Wharf, James City County, on the north bank of the James
River. It also crops out along the south side of the James
River from Cobham Bay north to Claremont Wharf. Mans-
field included part of the “Murfreesboro stage” of Olsson
(1917) with this zone. The lower beds at Murfreesboro,
Hertford County, North Carolina, are the deposits desig-
nated as “Murfreesboro” by Olsson. This name is pre-
occupied, as noted by Mansfield (op. cit., p. 8); hence
Olsson’s term is invalid. The lower deposits at Murfreesboro
are the only ones in North Carolina definitely referred to
zone | by Mansfield. It is not clear as to whether the beds
near Halifax, Halifax County, North Carolina, were in-
tended to be placed in zone | or zone 2 by Mansfield.
Zone 2, as defined by Mansfield, consists of coarse sand
in its lower portion, which occurs at Kings Mill Wharf and
at Yorktown, where it overlies zone 1 conformably. The
middle part of zone 2 (the fragmental beds) composed of
sands, clays, and shells, is exposed at Yorktown, according
to Mansfield.
Farther south, the localities around Suffolk, Nanse-
mond County, Virginia, have been inundated by water of
the city’s new reservoir. The localities along the Nanse-
mond River east of the city are still accessible. however.
The beds near Suffolk and the beds at Biggs Farm near
Franklin, Southhampton County, Virginia, were regarded
as the youngest Yorktown in Virginia by Mansfield.
According to Mansfield, the upper beds at Murfrees-
boro, the beds along the ‘Tar River near Greenville, Pitt
County, Tarrboro, Edgecombe County, and Grimesland,
Pitt County, North Carolina, and the beds along the Cho-
wan River represent some part of the upper zone of the
Yorktown deposits. He regarded the beds along the Chowan
River as the youngest Yorktown deposits. Richards (1950,
p. 23) also included some deposits along the lower Roanoke
and Neuse Rivers in Mansfield’s zone 2.
The lithology of the Yorktown formation in North
Carolina is similar to that in Virginia. The western limit of
the formation in North Carolina is from Weldon to Hali-
fax, Enfield, Halifax County, Rocky Mount, Edgecomb
County, and Goldsboro, Wayne County. The westernmost
Yorktown locality included in this study is Old Sparta
(locality 10). The southern limit of the Yorktown is near
New Bern, Craven County, North Carolina. Typical sec-
tions of the Yorktown formation were reported by Clark
and Miller (1912, p. 161) and by Mansfield (in Gardner,
G23 pal Oselly)ir
As a part of a statistical study of stratigraphic correla-
tion, Mansfield’s zonation of the Yorktown is examined (p.
27) and is found not to be useful. As defined by Mansfield,
Mip-AtrLANTIC ‘TERTIARY ARGACEA: Birp 0)
the deposits at Claremont, Virginia (locality 20), and the
lower deposits at Murfreesboro (locality 15) belong to zone
1. At Boykins, Southampton County, Virginia, about six
miles northeast of Murfreesboro, lower and upper zones
were observed and the lower zone (locality 17) probably
corresponds to the lower zone at Murfreesboro and _ is,
therefore, zone | of the Yorktown formation.
Localities 22 (Yorktown) and 21 (Kings Mill Wharf)
would be from zone 2 as defined by Mansfield. The sample
at Kings Mill Wharf was taken in and above the Chama
bearing beds and is, therefore, zone 2. Extrapolation from
Mansfield’s statements of distribution of zones 1 and 2
suggests that localities 18 (Morgarts Beach) and 19 (Court-
land) , both in Virginia, would belong to zone 2.
In North Carolina, the upper zone at Murfreesboro
(locality 15) was defined as zone 2 by Mansfield. The other
localities studied, with two exceptions, from North Caro-
lina are from Mansfield’s zone 2. It is not clear as to what
Mansfield regarded the deposits near Old Sparta (locality
10). Lack of observable zonation at Worrels Mill precludes
placing these deposits into one of Mansfield’s zones.
On the basis of the statistical comparisons of the
faunas of the localities above. Mansfield’s zonation does
not seem to be applicable. However, that the deposits
along the Chowan River are young Yorktown and Duplin
in age is supported by the statistical studies.
At places along the Chowan River the Yorktown for-
mation is represented by a lower blue-gray sand overlain by
a buff sand. The contact between the layers is irregular. At
Mount Pleasant Landing (near Harrellsville in Hertford
County, North Carolina), where both zones are well ex-
posed, the faunas of the two layers are nearly identical.
Richards (1950, p. 23) considered the lower blue-gray layer
to be Mansfield’s zone | and the upper bluff-colored layer
to be zone 2. The fauna of the two color-determined layers
are similar to those of others collected along the Chowan
River, all containing the characteristic Noetia (Eontia)
carolinensis Conrad.
Duplin marl.—TYhe formation was named from ex-
posures around Magnolia in Duplin County, North Caro-
lisa, by Dall (1898a, p. 338). The formation consists of
unconsolidated sand, clay, and much calcium carbonate; at
Natural Well the calcium carbonate is 77°; by weight of
the sediment (Copeland, 1961, p. 15). Exposures have been
reported (Richards, 1950, pp. 28-50) from localities in
southern North Carolina including: Magnolia (Duplin
County), Clinton (Southampton County), Elizabethtown
(Bladen County) , and Lumberton and Fairmont (Robeson
County). At Natural Well (Magnolia, locality 6), the for-
mation is represented by three feet of blue-gray sandy marl
which contains abundant fossils. The Duplin formation ex-
tends into South Carolina as far as Maysville, Sumter
County.
PLIOCENE
The only beds referable to the Pliocene in the area
under consideration are those of the Waccamaw formation
and the Croatan sand. The mean percent of the combined
gastropod and pelecypod species ranging to the Recent for
four Waccamaw localities and the two zones of one Croatan
locality is about 60°%.
Waccamaw formation.—The formation was named by
Dall (1892, p. 209) for exposures along the Waccamaw
River in South Carolina. In Horry County, South Carolina,
the Waccamaw consists of 5-10 feet of fossiliferous blue shell
marl. The Waccamaw formation in North Carolina consists
of poorly indurated fine quartz sand with occasional
quartz and phosphatic pebbles. The thickness of the Wacca-
maw formation is-not definitely known. Miller (Clark,
Miller, et al., 1912a, p. 250) stated that the thickness prob-
ably does not exceed 20 feet in North Carolina. The forma-
tion is exposed in North Carolina at Old Dock (locality 2)
and at Acme (locality 5), which are typical and richly fos-
siliferous localities. In this report the faunas of the Walkers
Bluff (locality 4) and Town Creek (locality 1) localities
are considered as Waccamaw on the basis of the statistical
study presented later.
At Walkers Bluff, the Waccamaw formation consists of
12 feet of shell marl and sand overlain by three feet of
coarse loose sand. Where observed, the formation rests on
Upper Cretaceous beds along the Cape Fear River.
Croatan sand.—Dall (loc. cit.) proposed the name
Croatan for beds along the estuary of the Neuse River. The
strata were named for the village of Croatan, 10 miles below
New Bern in Craven County, North Carolina. These beds
(as represented at localities 7 and 8) are shown to be
equivalent to the Waccamaw (as they were considered by
Dall) late in this paper. Recently, DuBar and Solliday
(1963) have studied the Croatan beds in detail. Their
studies indicate Pliocene age for the beds at localities 7 and
8. These beds are called the James City formation by them.
The Croatan sand lies with unconformity on the Trent
formation, which is questionably Eocene or Miocene, where
the lower contact of the Croatan has been observed. The
Croatan is overlain by Pleistocene deposits. The maximum
thickness is 15 feet near James City (localities 7 and 8).
10
is)
6.
“I
10.
te
12.
13.
14.
15.
16.
dive
18.
19):
20.
22.
PALAEONTOGRAPLILIGA
TABLE 1
REGISTER OF LOCALITIES
Town Creek, Brunswick County, North Carolina. Waccamaw
formation. Located 4+ miles southeast of Winnabow at the Pierce
Brothers quarry which is 0.5 mile north of county road connecting
N. C. 40 and N. C. 87, about + miles west of the junction of N. C.
40 and the county road.
Old Dock, Columbus County, North Carolina. Waccamaw forma-
tion. Marl pits along Hallsboro Road and along N. C. 130, about
1.5 miles north of Old Dock.
Acme, Columbus County, North Carolina. Waccamaw formation.
Marl pit 100 yards west of secondary road from Acme to Delco.
The pit is 0.5 mile south of the intersection of N. C. 87 and the
secondary road.
Walkers Bluff, Bladen County, North Carolina. Waccamaw for-
mation. At Milepost 60 on south bank of the Cape Fear River
8 miles southeast of Elizabethtown.
Lumberton, Robeson County, North Carolina. Duplin formation.
East bank of Lumber River 1 mile south of town, 100 yards west
Ge Wie Se 7k
Natural Well, Duplin County, North Carolina. Duplin formation.
Pit 2.5 miles southwest of Magnolia, on the farm of Mr. Albert
Matthews, about 500 yards southeast of farmhouse.
James City-lower zone, Craven County, North Carolina. Croatan
formation. At Quarantine Station, west bank of Neuse River, 1.5
miles below James City.
James City-upper zone, (same locality as no. 7).
lower zone by unfossiliferous mudrock.
Worrell Mill Pond, Northampton County, North Carolina. York-
town formation. South bank of Kirbys Creek, 3.75 miles northwest
of Murfreesboro.
Old Sparta, Edgecombe County, North Carolina. Yorktown for-
mation. South bank of Tar River, 1 mile below bridge on N. C.
42.
Williamston, Martin County, North Carolina. Yorktown forma-
tion. Bank of small creek 2 miles west of town on N. C. 125,
100 yards south of intersection of N. C. 125 and creek.
Black Rock, Bertie County, North Carolina. Yorktown formation.
West bank of Chowan River, 1.5 miles east of Black Rock.
Mt. Gould, Bertie County, North Carolina. Yorktown formation.
At Mt. Gould Landing, 1 mile west of town on the east bank of
Chowan River.
Colerain, Bertie County, North Carolina. Yorktown formation.
Landing 2 miles east of town on the west bank of Chowan River.
Murfreesboro-lower zone. Hertford County, North Carolina. York-
town formation. South bank of Meherrin River, 2 miles above
bridge on U. S. 258.
Murfreesboro-upper zone, (same as _ locality 15).
from lower zone by thin, unfossiliferous clay-sand.
Boykins, Southampton County, Virginia. Yorktown formation.
South bank of Meherrin River, 2.5 miles above bridge on Va. 35
about 3.5 miles south of Boykins.
Morgarts Beach, Isle of Wight County, Virginia. Yorktown for-
mation. South bank of James River, 3 miles above Smithfield.
Courtland, Southampton County, Virginia. Yorktown formation.
Sand pits just southwest of Hercules Powder Company plant
about 3 miles southeast of Courtland.
Claremont, Surry County, Virginia. Yorktown formation. South
bank of James River, 1 mile north of Claremont.
Kings Mill Wharf, James City County, Virginia. Yorktown for-
mation. Six miles south of Williamsburg, north bank of James
River, 100 yards upstream and downstream from the tower at
the Camp Wallace Military Reservation.
Yorktown, York County, Virginia. Yorktown formation. South
bank of York River, 1.5 miles above town; 200 yards north of
the Moore House.
Separated from
Separated
LOCALITIES NOT INCLUDED IN STATISTICAL STUDY
Longs, Horry County, South Carolina. Waccamaw _ formation.
From material dug along Waccamaw River bank, 2 miles east of
Longs.
Silverdale, Onslow County, North Carolina. “Trent formation.”
Mar! pits on Gillette's farm 10.5 mile southeast of Silverdale.
AMERICANA
(V, 3:1)
pole
he, a
NORTH \ CAROLINA
Ree
)
I See ok
—_ { on sxe com |
he
PN cotumaus ca’
Bie MAP OF COLLECTING LOCALITIES
|CAROLINA SM usin os PGE en fo miLes
Le a
BAG ee is =p 716°
f es =
C. Haywood Landing, Jones County, North Carolina. ‘Trent forma-
tion.” On east bank of White Oak River, and 100 yards east, 4
miles northwest of Kuhns.
D. Willow Green, Pitt County, North Carolina. Yorktown formation.
Marl pit located on road leading from Willow Green (Greene
Co.) to U. S. 267. About 0.13 mile north of swampy stream form-
ing county line.
E. Plum Point, Calvert County, Maryland. Calvert formation. On
west shore of Chesapeake Bay, about 1 mile north of Plum Point.
GEOLOGIC HISTORY
The basal upper Tertiary deposits of this study are
those marine strata referred to the lower Miocene in Craven
County, North Carolina. The sea withdrew after deposition
of the sediments in the Silverdale, North Carolina, area
until mid-Miocene time, when the Calvert formation was
deposited from Maryland to northeastern North Carolina
where Calvert and Choptank equivalents have been identi-
fied in the subsurface (Brown, 1958, Table 1). According
Mip-ATLANTIGC “VERTIARY ARGACEA: BIRD 1]
to Brown, these subsurface deposits were formed mainly as
chemical precipitates of phosphates intermixed with fine-
grained clastics in a restricted basin with limited access to
the open sea. The Choptank formation is sparsely repre-
sented in Virginia. The St. Marys formation was deposited
at least as far south as the Meherrin River in Virginia. The
formation is not definitely known from surface or subsur-
face deposits in North Carolina. During the deposition of
these three formations comprising the Chesapeake group
(middle and upper Miocene) the immediate source area
was low. The clastic sediments are fine and locally diatoms
are concentrated to form commercially important deposits.
The northernmost occurrence of Yorktown beds is
northern Virginia. Southward, the sea covered the northern
one-third of eastern North Carolina during early Yorktown
time. No deposits of older Yorktown age are known to be
present south of New Bern, Craven County, North Caro-
lina. The Cape Fear Arch, a broad arch trending northeast
from Wilmington, North Carolina, may have been elevated
at this time and thereby excluded the sea from southern
North Carolina. A younger phase of the Yorktown forma-
tion is represented by the beds along the Chowan River and
at Williamston, North Carolina. The correlative Duplin
marl, in southern North Carolina, represents the first ad-
vance of the sea in that area since upper Eocene or possibly
lower Miocene time. The Cape Fear Arch was then sub-
merged and remained so during lower Pliocene time when
the Waccamaw formation and the Croatan sand were de-
posited.
ECOLOGY AND STRATIGRAPHIC RELATIONS
Discussion.—Faunal lists of all identifiable gastropod
and pelecypod species were prepared (Table 2) in order
to ascertain the stratigraphic positions of the beds at the
important localities. These lists were statistically analyzed
by the Rogers-Tanimoto method (1960). Match coefficients
(Matrix 1) were calculated by dividing the number of
species in common for each of the 22 localities in ‘Table |
by the total number of distinct attributes. For example,
localities | and 2 have 22 species in common, locality 2 has
51 species, 52 of which do not match with those of locality
1. Locality 1 has 29 species, 7 of which do not match with
those of locality 2. Hence the match coefficient is the total
number of species in common (22) divided by the total
number of distinct attributes (32+7+22) or 22/61. The
total value for each locality is obtained by summing rows
and columns in the matrix. The locality with the highest
value (locality 6) was taken at the prime node and clusters
were sought between successive members of the typicality
ratings (/.c. total values arranged according to rank, ‘Table
3)
Clusters were allowed to form when the U, value (the
ratio of the calculated distances expressed by match coeffi-
cients between members of the clusters and the hypothetical
perfect case in which all distances or match coefficients are
equal) for the cluster being tested was not decreased on
dropping the most atypical case from the cluster. (For
equation used in calculating U, see Equations for Statis-
tical Analyses.)
Findings.—The pelecypod and gastropod fauna from
the Duplin marl at Natural Well, North Carolina, is the
most typical of those studied, 7.c. this locality and horizon
have more species in common with all other localities than
any other. Locality 6 (Natural Well) and the next most
typical case, locality 5 (Duplin marl, Lumberton, North
Carolina) occur in clusters 1 and 2 but not in cluster 3
(Waccamaw and Croatan beds) (Table 4). For purposes
of correlation, localities 5 and 6 are relegated to cluster 2
on the basis that the percent of gastropod and pelecypod
species raging to the Recent at these two localities is lower,
in keeping with other Miocene faunas in cluster 2, than the
percent of Recent species in the Pliocene faunas of cluster
3. (Table 4). Further, the mean of the match coefficients
between the localities of cluster 2 and localities 5 and 6 is
higher than for cluster 3 and localities 5 and 6, when match
coefficients are based on the maximum number of species
in common, ?.¢., when the number in common is divided by
the number at the locality having the fewer species.
The Foraminifera of each locality were identified to
genus and their abundance recorded (Table 5) to help
determine whether the relationships outlined above were
the result of age or ecological differences. ‘The interpreta-
tion of data is based primarily on Lowman’s (1949) find-
ines on the distribution of foraminiferal genera from the
Gulf of Mexico. The genera from the following localities
are interpreted as shallow shelf (less than 20 fathoms, Shep-
ard and Moore, 1955, p. 1539) assemblages: Localities 2-8,
and 12. The rest, with the exception of 9 and 10, are outer
shelf. Only two specimens of Foraminifera were found from
the sediment at locality 9 (both belonged to the genus
Robulus) ; lack of sediment in my collection precluded
analysis of Foraminifera at locality 10. The Foraminifera of
locality 6 have been studied by Charles W. Copeland
(1961) who concluded that the fauna was shallow shelf. A
comparison of the relative abundance of genera at each
locality gives indication of more refined differences. How-
ever, the zonation into inner and outer shelf shows that the
clusters formed are not related to the inferred depth of
2; PALAEKONTOGRAPHICA AMERICANA (V, 34)
TABLE 2
Gastropoda and Pelecypoda Species from Localities in Table 1
———————————————————————————_—_—______________________ 1 TTTTEIETETTTTTEETTTEEEEEEEEEEEE EERE EERE
localities
Td
Species Th Bees Ih Oy {3 4) eb ay ale avi, ally alisy aly? Ne} SIG) 0) al,
a
CLASS GASTROPODA
Family Fissurellidae
Diodora
D. griscoma (Conrad) Sey US a St SP eae Sa a Ba RS Re a Re Re
Family Trochidae
Calliostoma
C. basicum Dall - R Ree | ia a a i =) fa" ah Sa) Sar hea Reo = Beer:
cf. C. aphelium Dall Se Hee ee er SS ose co Se & eb es S&S Se so R
ef. C. virginicum (Conrad) a ee =e +e 2 ES SPSS Se eae
Family Liotiidae
Arene ‘
“A. gemma (Tuomey & Holmes) = Reh (et a Ss TI See Se oe SS = 5 =
Family Eptoniidae
Epitonium
“ef, ©. antillarum (DeBoury) — cap ER JS Ss Se SS = we le a I i ee et a aes Ga
cf. 5. pratti Gardner a a en hn ge 5 ae eh eee = ge RO = OR ee
Family Uulimidae
Sulima
cf. E. eborea Conrad SoS I So a Ss eS fe 4 S se seodl See fe BS ee oe
Niso
cf. N. lineata (Conrad) Se CR ge ORD ere Ve SS eee es es) Sr eS oS OS Oe
Family Turritellidae
Turritella
T. duplinensis (Gardner & Aldrich) oO Ff Boe se a 6 & = es re Re ae eer
ef. T. alticostata Conrad = = = = = = = = R Ss of
T. variabilis Conrad = =- = =- C€ R = = Roy Ris er RE les emt lo oe ee
Vermicularia
*ef. V. spirata (Phillipi) a ts re oe ey Bers = ml bay SSS Sh Se Se ee eee eee eee
1
1
fof
too]
wm
Eo}
!
!
bes
mal
Family Architectonicidae
Architectonica
cf. A. nupera (Conrad) S Sf ses fe = SS SoS io aS Ss er eS SS Ss SUD
Family Caecidae
Caecum spp. ea = = R= = = = ee hee Mh ow AO eo
Family Thaididae
Eephora
B. quadricostata (Say) = ee ee Pee et A es MM co in an 2S
Family Nassaridae
Nassarius
N. (Ilynassa) arata (Say) oS
N. (1.) irrorata (Conrad) = =
ef. N. (1) scalaspira (Conrad) = 6
N. (Nassarius) chowanensis (Gardner) a t l
N. (N.) suffolkensis (Gardner) Sj 2 Gh = & S&S Ss © < 20S EO Fa eS ee en
*N. (Hinia) trivitata (Say) t - - - - - - - - - - - - - - - - - - - - -
aqanw!
Family Melongenidae
Busycon
*ef. B. canaliculatum (Linné) RR OR 2
°B. contrarium (Conrad) Ref i ER TE SG B86 0 AE pee ee a en ee
wd
oy
1
1
!
!
!
'
!
1
!
1
!
!
!
!
1
!
Family Fasciolariidae
Fasciolaria
F. sparrowi Emmons SS fb 8 ao «¢ OC Se Sf a AW ot SRE Se ee ee
F,. cronlyensis Gardner = S = = = Re v= s = = = a 5 S = = a & = = = =
Fusinus
ef. F. exilis (Conrad) Reed CASH GIR: ee Ss oe eae ote Samy es PE SY SS: GS
Lirosoma
L. sulcosa (Conrad) ey Pa ee ee, ey eS so) ek he oS or eh a
Family Olividae
Oliva
“ef. O. litterata Lamarck
Olivella
ef, O. mutica (Say) = iP eh ON Se Sey NIN Ao Sh Se
(=)
Q
i}
!
Qa
!
i}
1
!
!
i}
'
i}
!
!
i)
R - - - -
Mip-ATLANTIC “TERTIARY ARGACRA: Brirp 15
TABLE 2 (cont. )
Localities
re a ESS
Species LS Sh HR hy, ley 7 EY a) ale) gal” a algy aA, aly) alley ale? aie} IG) 20) A a
Family Mitridae
Aurinia
cf. A, mutabilis (Conrad) Oo poh Be et Sg oT on bo ai OS i Se Se
Family Marginellidae
Marginella
M. limlata Conrad = 1G, R = We R - - R = Re ee R= = RR
Family Cancellaridae
Trigonostoma
cf. T. tenera (Phillippi) S eG iho we Se te sce Se ee Oe FOR OM Moo ieee ey ss
Family Vermetidae
Lemintina spp. =e CL) CCS RACY t=) Smt = ee et Aue ees ee SS oe)
Family Calyptraeidae
Calyptraea
*ef. C. centralis (Conrad) =a hee Chag— we CM Sy. oe SS ee eS SS, 8S
Crepidula
*ef. C. fornicata (Linne)
*C, plana Say
Crucibulum
C. costatum (Say) Ss > WW 26°56 “Go So ee ae) ee i
cf. C. pileolum (Lea) et Ne wee de ! I
ma
Q
>
J
f=)
Q
'
!
sols}
1
ry
1
1
1
t
Family Naticidae
Polinices
*P, duplicatus (Say) NM -G- i GR RR ef Ss = = — ee ee ee a a
Lunatia
*L. heros (Say) CHP ct gm ORE Sree | ee Ce os te ei eet ih) MOCO ese Tjrh ied: el
Family Cassidae
Sconsia
cf. S. hodgii (Conrad) So oe SF PR RM ao o ae te") Sh oe (S64 Be Sa aa es Pe
Family Ficidae
Ficus
*F, communis Roding af es Veh Sey on ies Ute = SOT eo acme a en ee ee Se
Family Muricidae
Murex spp. Se Ae ae CS ee es ee ie ee eee eee a my
Tritonalia
*cef. T. cellulosa (Conrad) Sey ae Ne ee A Pan) awe (ae ea Se We. tay fe) eye ee eee
Muricopsis
*ef. M. ostrearum (Conrad) =k Yo ae ee oe ee By oe, alee 2) Ey ark wey Cay Se ae oe
Ptychosalpinx
P. altilis (Conrad) i ee a a he Gane bah Ze ee CPT Rape! he ae ee ae ae
Urosalpinx
*ef. U. perrugata Se Sie 8. hea ee AE eS aD ae Oo re ee ie UR. Whee eee
cf. U. suffolkensis Gardner S. Th oe (9S ee ke ie) Sue See IS Sa
cf. U. trossula (Conrad) a a a eS ee en a OR: Rn heey ee) Biles Vile eeetess: Boe eh SG
Family Columbellidae
Anachis
ef. 4. styliola (Dall) WS TS. eS TS Aa = SONG Sic woe eo ee toh Ao i
Family Turridae
Crassaspira
C. perrugata (Dall) Reh ras ee: Semone Say ee Bay Se ere fee ee) Se ee
Family Conidae
Conus
cf. C. adversarius Conrad a Ose:
Family Terebridae
Terebra
“ef, T. (Oxymeris) dislocata Say S i
pe
Q
Q
i)
'
1
'
1
!
1
1
1
1
i]
'
1
1
i)
CLASS PELZCYPODA
Family Nuculidae
Nucula
“N. proxima - - - - - C Cc Cc - - - - R Cc - - - R - - R (e
14 PALAERONTOGRAPHICA AMERICANA (V, 34)
TABLE 2 (cont.)
Localities
Species TO Re} 4 5 6 GY 3 9 CO} sais alee als} avi, aly) al) 3G? GN}. SIG), YO)” AA,
Family Nuculanidae
Nuculana
‘N. (Saccella) acuta (Conrad) ee Me) Sp Sol NS =o jee GRY SG 2S Sy ee Cheer
Yoldia
Y. laevis (Say) ce Se oe Ss 6c 2 = S&S Soe oes SS Ss Ih SG G6 oo 6
Family Arcidae
Anadara
*A, (Anadara) transversa (Say) WG i "GiGi ie oe A sts (SER, (Cp 0 fa ee
*A, (A.) lienosa (Say) CP UR ee a RS
A. (A,) carolinensis (Dall) See ie Biro re a) oy WE Go i, ke 8 tw See Se ee ee
*h, (Cunearca) incongrua (Say) = (R= = =F == ee ee ee ee en Le
Arcopsis
*A. adamsi Dall —- 2 © ie) = == a ee ere eS SS OS Sle
Striarca
S. centenaria Conrad oh ea a ae a ae a ae a ae et SS er tS Se em CCC
Noetia (ontia)
N. (£.) trigintinaria (Conrad) Se Se on > Ge 6S joe So eee eS” ee eee
N. (&.) incile (Say) ee Sa So ao Se Se ae & CR &
MN. (£.) platyura Dall A IR =) (CG = Si ee ee SSS
N. (4.) limula (Conrad) He Se) See a IO a= 8 = tH ee
N. (%.) carolinensis (Conrad) Sos SO Ss S&S os S&S & oo = ay AC oR Rr n= ee
Glycymeris
“G. americana (Defrance) NR I eh ee INE es SS Se OS @ So Ge Se = & S&S Ss © =
“G,. pectinata (Gmelin) Ro OG A oer SIS te SB Ce’ SB Ss £& B6@ Ss So & SB es Seas
G. subovata (Say) SS oe 5 GC Ge so © AS Ce (C0 Ce Ce Ce RECS ie Ce Cr ee
G. lentiformis (Conrad) Se) ee to oe oS eS, es Gos Ss S&S RR
Family Ostreidae
Ostrea
QO. sculpturata Conrad CG SAR oR IC RS s=) (=) IC =) Pa tae yas ae el eee col) uO
QO. disparilis Conrad Sey gfeete fest g resp ier ta cee! =e te fae er) OR Ta eee ea
Family Plicatulidae
Plicatula
cf. P. marginata Say - mR 3C — = 4G) =— = = ee Res COR} Ce = Sa a R
Family Astartidae
Astarte
4. concentrica Conrad = 1G Re C) Ge fa vey = Ry Cs ee ORY CE y ay as — eC
A. undulata Say -~- = =- = = = = = R C45 Se Sie Ceo G& Ae eS Ce
Family Pectinidae
Chlamys s.l.
C. eborea (Conrad) Mes Se oS we - Se OR =. UR) Ss sR Ad. See eee eee
C. virginiana (Conrad) Se ae ep eee ea es Sd URIS ee eee
C. clintonia (Say) Sy ASP hg Sige ee 25 eS = = eh Sa Ce Re ee Ce
ef. C. marylandica (Wagner) Sooo 2 = Ss Ss S £ = See ee Ss PR Se Se Sp Sse oo «6
Aequipecten
A, (Plagioctenium)
A. (P.) comparilis (Tuomey & Holmes) RG eR RR Ce 7 Rae =0 =) eee a en eR
Lyropecten s.l.
cf. L. jeffersonia (Say) 5S 6 Ss Sato Ss te = C CG. vey oS 2S OG Ri ca Ce Cer
Pseudoamisium spp. oe Ra SS e & S&S 2 6 Soo oo oe op CG SG oe se S&S S&S cs sc
Family Anomidae
Anomia
*ef. A. simplex (d'Orbigny) Sew eS) eS eo RP ta. Sa) pee UR ie SS oe = ee
Family Crassatellidae
Hucrassatella
*cef. E. speciosa Adams A R C = R R - = = = = = RRS v=, 3 = = = = = = =
Crassatella
C. undulata Say See & =o Ho Se oma wees Ite lee egy Ge
Family Carditidae
Carditia s.s.
C. (Carditamera)
*C. (Carditamera) arata (Conrad) i i TGS Rs Se os Ss = 5s = C6 Ss & RR sc
C. (Cardita)
C. (Cardita) granulata (Say) > We Ce ey Ry @ Soe Vt Soe i Cree SG aa Mh i i ag
Cardita s.l.
ef. C. tridentata (Say) SC RG Re Sooo Ss Ss Se ee rc ee SR
*C. perplana (Conrad) Se 48 6 S&S So slus -s Ody ee ee ee eee
Mip-ATLANTIC TERTIARY ARCACEA: Birpd 1!
TABIEZ 2 (cont. )
aaa 7°-—-GGlQOloeaaesSs=s=«qonaaoaaaaaeleleeeeo=$=$=$q$q$q$q$q~qao eee
Localities
Species i 2B 3 4 5 6 fh axe SC) nfo) abi a aby ah, aly. aleyy aly? fle} als) Alo) pal A)
Family Corbiculidae
Coroicula
C. densata (Conrad) = te Sey es iS ap Sy) So SS HM Ss a8 4 2 Ss =
Family Lucinidae
Lucina
L. (Callucina)
*L. (C.) floridana Conrad CG jth cs oh Sea SoS oS Roo SS Se lo es IS ao SoS SS Se a
L. (C.) paranodonta (Gardner). = i Js 2 ah Go a “Ss = as S Ss © Ss Ss 2 Sos a's
L. (Cavilinga)
*L. (C.) trisulcata Conrad o oR WM se es & 5 Ss CO PP Soo SS Ma 6S co «&
L. (Lucinisca)
L. (L.) cribraria Say > OP Oy po a ees or Sos SS Seo aS a FR Wy eS MS
L. (Parvalucina)
*L. (P.) multilineata Tuomey & Holmes > Rom Sse so 6 & 2 cs Se = ff so Ss SF S 6 Sf Go oo Ses
Lucinoma
L. contracta (Say) Se er ee =a a ee ae OR cle ee Oc eee
Divaricella
*D. quadrisulcata (d*Orbigny) —pew Ree Racy ee a oe OS Re Bee Ss Sta SS MS eS co Se
Family Ungulinidae
Taras
T. leana (Dall) Sees e Pe ee et aN a ES ee Se ee ee ee en
Family Chamidae
Chama
*C. congererata =e ke MC) pa Ra om ta OR PR SKS Ss oe Ss fo co © RP Ss Ss
Schinochama
“ef, ©. arcinella (Linné) =e GC ee eae a tm em: km See te Ce erga hie ae an
Family Cardiidae
Trachycardium
*ef. T. muricetum (Linne) mice Ji hi a a a =) = SOO me me neg Im me
*T. epmontianum Shuttleworth I ( - - - - - - - - - - - - - - - - - - = -
Laevicardium
L. sublineatum (Conrad) =e Che KT Pay ae aR a aper t= shat a ae fm. te ime = amd Bn om mr
Cerastoderma
C. laqueata (Conrad ) tape eee el wok ie ee Ce See CS me Ae ce Se oc tS
Family Veneridae
Chione
*ef. C. cancellata (Linné)
*C. latilirata (Conrad)
Macrocallista
*M. reposta (Conrad) Ree Ree eRe fs hed a os Uy A ee BO ore oy ee
cf. M. emmonsi Gardner - - - te TS ee =) a ea ah ea an ae a a a
Dosinia
D. acetabulum (Conrad) ao 6s 5s 6 S&S 6 = F Se 2s ££ Ss & Foe Ss 6s S&S 5S «=
Mercenaria spp. A C¢ RR Re or 6c R R - xo ee ie a I eS ea GR yc
Gemma
cf. G. magna Dall - -
aQ
at
ro
Family Mactridae
Mactra sp. = foe ea ay RE a ey Pe SOPs Oh Sac SO Sr ae
Family Isocardidae
Isocardia
I. fraterna Say So joa Ce io te G56 “Oo. e Ss oy (Ss, os. aS
Mulinia
M. congesta (Conrad) Re eS i VN ag SP an Poets € 6. Hoa RM oa 6. mk a
Spisula
*ef. S. solidissima (Dillwyn) CHG}, RuGe Wahie aal ae he on Fo eon Cee ee eee ee
yy
1
1
i
1
Family Tellinidae
Apolymetis
A. magnoliana (Dall) Se er OT ee ee en ee a ee oa PE ao a Be” ee
Family Donacidae
Donax
*“D. fossor Say ay i) i Ai Be Coe ee =e ea Y fa a eS a e a aS e
Family Saneuinolariidae
Tarelus
*ef. T. plebius (Solander) occ.) i! tS iS eo Soe SB) DEON, Dee oe ey
PALAEFONTOGRAPHICA AMERICANA
(Ved
TABLE 2 (cont.)
008 SS
———————— ee
Localities
Se eee
Species Thy Pe Sh fk yy 6
Seo, Woy Alb alee aley) vk ale ale), a7? als} GS) 0) AL 2
Family Semelidae
Semela spp. -
“ef. S. bellistriate (Conrad) =
Cumingina
C. medialis (Conrad) iS eS See ot
Abra
“A. aequalis (Say) =f) eee: ey G5
pee]
eole~s]
Family Solenidae
Mnsis spp. - R R R
Family Corbulidae
Corbula
C. inaequalis Say = G Fen: - -
Family Histellidae
Panope spp.
Family Pholadidae
Barnea
B. arcuata (Conrad) ee ey a Rabe
R
is)
A — Abundant
C - Common
R — Rare
* — Ranges to Recent
absent
Symbols:
q
Relative abundance is based on general impressions of a particular fauna and is subject to such bias as unequal sample size,
selective collecting (though crab samples were taken to insure collection of most species), and weighted estimation because of large
size or uniqueness of form in some species.
water at each station. The clusters of Table 4 in general
follow preyious notions of correlation in the area of study
and the average percent of gastropod and pelecypod species
ranging to the Recent is distinct for the clusters. ‘This evi-
dence supports the idea of treating members of the clusters
as stratigraphic correlatives.
Conclusions.—|. The localities of cluster four (Nos. 9,
10, 15-22) are considered approximately equivalent in age,
and the beds are thought to be older than those of cluster
2 and 3 because: (a) This cluster has a lower mean percent
of gastropod and pelecypod species ranging to the Recent
than the other two clusters. The average percent of species
ranging to the Recent for cluster 4 (21°%) is decidedly low
for upper Miocene beds. However, the average is brought
down by localities with sparse faunas. Localities 9, 17, 18,
21, and 22 have 297
oO
of their species ranging to the Recent.
This is still low for what would be expected for upper
Miocene deposits. ‘Phe percentage suggests middle Miocene.
(b) The ranges of several species found in the Chesapeake
group extend to localities of cluster 4 and do not extend
into the clusters of younger localities. Striarca centenaria
(Conrad) occurs at Yorktown localities 20, 21, and 22, and
in the Chesapeake group. Lirosoma sulcosum (Conrad) and
were found at Yorktown
99
£43
Ptychosalpinx altilis (Conrad)
localities 9, 15, 17 and 15, 17, and respectively. Both of
these species are also found in the Chesapeake group. The
well-known Ecphora quadricostata (Say) was found at
localities 15, 17, 18, and 20 and is found in the middle and
upper Miocene Chesapeake group. Though Glycymeris
lentiformis (Conrad), which is here proposed as the mor-
phological intermediate and, therefore, intermediate in age,
between G. parilis (Conrad) of Calvert age and G. ameri-
cana (Defrance) of upper Miocene to Recent age, is abun-
dant at locality 17. G. americana is sparse in the group of
localities. Finally, Noetia (Eontia) incile (Say) is present
at localities 18-22; no species of this subgenus are present in
the other members of cluster 4, but species apparently
evolved from it are present in the other clusters. N. (E.)
incile is restricted to the Chesapeake group and the lower
Yorktown. Therefore, it is inferred that cluster 4, the mem-
as correlatives because of their
clustering, is older than the other clusters of this study and
bers of which are taken
is pre-Duplin Yorktown in age.
2. On the basis of this statistical study, Mansfield’s
faunal zones of the Yorktown do not seem to be justified.
‘The same conclusion was reached by McLean (1956) and
Sabol (1960) based on foraminiferal studies. As stated by
Mansfield (i Gardner, 1943, p. 8), the beds along the
Chowan River seem to be younger than most parts of the
Yorktown formation. However, Mansfield’s zones 1 and 2
at Murfreesboro (localities 15 and 16, cluster 4) were not
separable according to this study nor were the deposits at
MATRIX 1
Match Coefficients for Localities in Table 1
Locality no. 2 3 4 5 6 7 8 Or, eo. ele eel oe 413 Th. 15 16 «I? } is 19 200s ae
a pol e27o Ol) .35h .30 sD, 126 1087 .053° £061 077 .152 .208 .083 .068 c432 a Joe cores lee
2) e5d3° sel “shO6 4333-2123 2170 .087 .083 1088 .098 .238 .297- .100 .075 079.156 Gos sao eee
5 <29) 2382 2260 .079: +123 .129 030° 1064, .076 .206 <279 3095 <070 2059 S190) sia cOrqeeel eee
4 oh67 2236 .061 .098 .085 .108 .1I6 .075 .200 .229 .060 .043 <04S “1100 3073) JONG) cues
5 sh68 .070 159 .I8B. 129 .156 1065 .276- 354 2103 .080 20) ie 0a cee ee
6 e117 2152 2135 4.103) 0179 «.O4l 2346S 23h «26973 «943 056 CSE so oO ee
7 0389 .107 .105 .000 .095 .133° .147- 100 .037 .143 5h Oo ok oe
8 090 .000 .045 <.037 .182 189 <027 <O45 .195 2250) 096 07 slo eel
9 2231 3160 6172 2125 2136) ehh 2392 2296 <2 e207) aeons
10 «267 3043 133. .154 .259 .208 2136 2107 Sole. 238) 99
11 2050 .333 .19% 061 .074 042 ~069 2136 2130) [407-272
12 0156 .200 .091 .107 .125 «196 3096 9.036 [050-09
13 oh32 4119 4105 2086 2158 2152 a? ieee ee
U, o106° 4068 075 195° «132 %.100) 41955 cee
1 «518 2370 «228 42679 2310 2226 ere
16 0231 2188 .333- «333 22200 eere
17 o2U, 2167 «160 22890 2760
18 2). 2207 2375. 22nd
19 0450 2259 2161
20 2296 4156
21. «355
Mib-ATLANTIC “TERTIARY ARCACEA: Birp 17
localities 17 and 20 (which seem best assigned to Mans-
field’s zone 1) separable from the other localities in cluster
four. If retained at all, it is suggested that zone 1 be used
for the localities in cluster 4 (which includes some of the
original localities attributed by Mansfield to zones | and 2)
and their correlatives. Zone 2 should be used for beds along
the Chowan River and their Yorktown equivalents as indi-
cated by cluster two.
3. The suggestion by Mansfield (loc. cit.) that the beds
at Biggs Farm (near Courtland, Southampton County, Vir-
ginia) are much like those from Natural Well does not
seem to be justified. Water has filled the pit from which
these fossils were taken, but pits made near the Hercules
Powder Company Plant near Courtland, Virginia, (locality
19) are in the vicinity. The fauna from this locality shows
its alliance with cluster 4 discussed above, and not with
the fauna at Natural Well.
4. Cluster 2 includes the Duplin beds of Lumberton
and Natural Well. The more northern representatives of
the cluster (localities 11, 13, and 14) are judged to be cor-
relatives. The reasons for assigning localities 5 and 6 to this
cluster, rather than to cluster 1, are discussed above.
The beds at Mt. Gould, North Carolina, were consid-
ered to be the youngest Yorktown beds in North Carolina
by Mansfield (op. cit., p. 12). He considered those at near-
by Colerain to be a little older. MacNeil (1938, p. 19)
equated the beds at Lumberton to those along the Chowan
River but younger than those at Natural Well. From the
Statistical study, it seems best to consider all these localities
equivalent in age. Based on the relatively common occur-
rence of Glycymeris americana (Defrance) , the beds around
Suffolk (not included in the statistical study) would seem
to go with cluster 2. Cluster 2 is intermediate in age be-
tween clusters 3 and 4. The evidence for the intermediate
position is: (a) The average percent of pelecypod and
gastropod species extending into the Recent at this group
of localities is intermediate (44%). (b) Localities 6, 11,
and 13 have abundant populations of G. americana which
become more abundant in younger Miocene and Pliocene
faunas. These populations do not show the variations of
those observed in localities of cluster 3. G. pectinata, a
species which is common in some Pliocene localities, is ab-
sent or rare in localities of cluster 2. Every locality of cluster
2 contains G. swbovata (Say) : none of cluster 3 contains this
species, whose known range is Miocene.
5. The localities of cluster 3 are from the Waccamaw
formation. Localities 7 and 8, from the Croatan sand, are
added here because of the high match coefficients they have
with the other members of the cluster when the maximum
possible number of matches is calculated. Also the average
percent of gastropod and pelecypod species ranging to the
Recent at localities 7 and 8 supports the addition of these
localities to cluster 3.
A lower Pliocene age for the Waccamaw formation and
the Croatan sand is confirmed. The mean percent of gastro-
pod and pelecypod species ranging to the Recent in cluster
3 is 60%. The presence of Noetia (Eontia) platyura, N.
(E.) limula, Glycymeris pectinata, and the genus Echino-
chama are characteristic of these beds.
6. An upper lithologic zone of the Croatan sand at the
James City locality is separated from a lower zone by a thin
unfossiliferous mudrock. In the present study, faunas of
these zones could not be distinguished, and both are re-
ferred to the Pliocene.
7. The foraminiferal faunas at each locality indicate
that, with one or two exceptions, those beds north of the
Chowan River represent deeper water than those along the
Chowan River and southward at least to the Old Dock,
North Carolina, locality (No. 2).
TABLE 3
Typicality Ratings from Matrix |
Sum o
Rank Locality Match Coefficients
| 6 4.404
2 5 1.386
3 14 4.248
4 9 1.074
5 13 4.053
6 2 3.994
if 15 3.968
8 21 3.845
9 18 3.781
10 22 5.508
1] 16 5.556
12 3 3.448
13 19 NY
14 20) 3.313
15 | Al
16 | 3.211
17 17 3.165
18 10 2.989
19 8 Dye
20 11 2.515
21 a 2254
99 12 1.847
18 PALAEONTOGRAPHICA AMERICANA (V, 34)
TABLE 4
Clusters Formed from Analysis of Matrix 1
1. Localities 1, 2, 3, 4, 5, and 6. U,—0.007.
». Localities 5, 6, 11, 13, 14. U,—0.013. Locality 12 is added
here.*
3 Localities 1, 2, 3, and 4. U,—0.050. Localities 7 and 8 are
added here.*
4. Localities 9, 10, and 15-22. U,=0.001.
*These localities are tentatively added to the respective clusters
because of the relatively high match coefficients between the localities
and the members of the original cluster when the match coefficient is
formed by dividing the number of species in common by the number
of species present at the locality having the fewer species. This addi-
tion to the original clusters is supported by the similarity of the per-
cent of gastropod and pelecypod species ranging to the Recent for the
localities added and the members of the original cluster.
GLOSSARY OF STATISTICAL TERMS
Case—an entity in a matrix, for example, a_ particular
species or locality in the two matrices in this paper.
Cluster, clump—a group of similar cases.
Distance dj,,—distance between case i and case j in the
matrix; indicates degree of similarity of cases 1 and j,
where i is the row position and ] is the column position.
d,,=—logs Sij-
Distance s,,—ratio of number of attributes in common in
cases i and j to the number of distinct attributes of the
two cases. Also called match coefficient in this paper.
Matrix—a series of rows and columns in which each case is
compared to every other case, as in a mileage chart.
Match coefficient—same as distance §;;.
Q—technique of analysis—a statistical approach in which
individuals are compared. ‘The comparison may be
made in at least two ways: (1) calculation of correla-
tion coefficient of two individuals at a time (Sokal and
Michener, 1957 and 1958), and (2) calculation of
match coefficient (s;;) for two individuals at a time
(Rogers and Tanimoto, 1960). In both methods many
characters (usually 40 or more) are selected and di-
vided; then comparisons are made on the basis of the
number of characters in common between all possible
combinations of individuals taken two at a time.
Prime node—the most typical case in the typicality rating.
R—technique of analysis—the common statistical approach
in paleontology in which characters are correlated. For
example, the calculation of the regression or correla-
tion coefficients of height and length of n individuals
of the same species.
‘Typicality rating—the characterizing of the cases in which
the sum of the s,; and dj; distances for each case (by
summing along rows and columns) is calculated. In
this paper the sum of the $;; distances are presented in
the typicality ratings to facilitate interpretation. Hence
that case with the highest total is the most typical 7.e.
that case which is most likely to have attributes pos-
sessed by all other cases.
U,—the ratio of the actual distances between cases (d,;)
calculated and the hypothetically perfect situation in
which all distances are equal. The method for testing
for clustering.
EQUATIONS FOR STATISTICAL ANALYSES
A. Bivariate analysis:
Regression coefficient or slope of regression line
(=tangent of slope angle, hence percent of slope) :
See Simpson, et. al., 1960, py22ie
t—test for comparison of regression coefficients:
See Simpson, op. cit., p. 229.
B. Multivariate analysis after the method of Rogers and
‘Tanimoto (1960) :
sj;—an example to illustrate the calculation follows:
* Character A B iG D E
Attribute abc abcde abcdef abcd abcde
Case I XO0OO OOXO00 OO000X0 X000 oOo0xo0o
Case II XOO OO000X OO000XO0 0000 00x00
Common X00 00000 O0000X0 0000 00x00
Distinct XOO OOXOX OOO00XO0 X000 oO0xo00
$,;—=no. of attributes in common=—3/6—1/2
no. of distinct attributes
d;;——log, s,;;——log, 1/2=1.0
Typicality value (or rating) sum or rows and col-
umns for each, 7.e. the sum of n-] distances if there
are n Cases.
*The character is divided into class intervals or qualitative as-
pects as color, shape, and the like. In stratigraphic study, the genus
is the character and the species the division or attribute. Only one
attribute is permitted per character in morphological considerations;
but where genera are used as characters, more than one match per
character is possible.
di; di;
TE, [ Gis) J=—1/2 Sy Tal (dy) ] logs TL (di) ]
TT, [ (dij) J= 1/2 (Sig ii)
Ux [ (dis) J=1-E, [ Gis) J
€n
Mip-ATLANTIC ‘TERTIARY ARCACEA: BirD 19
E,—Entropy or degree of dispersion expressed in terms
of di;
T,—Normalizing factor
€,—log, n/2 (n-1)
n—number of cases
U,—see glossary
+The operation of taking half the sum is not necessary if a par-
ticular ij and the corresponding ji are considered only once.
QUANTITATIVE MORPHOLOGIC FEATURES AND
SIGNIFICANCE LEVELS
The systematic relationships of species in the genera,
Anadara, Noetia, and Glycymeris, are studied with the aid
of bivariate analyses. In these studies, the regression coeffi-
cient of two characters at a time is compared to the regres-
sion coefficient of the same two characters of another
sample. (The characters presented were chosen based on
graphic comparisons of many combinations with subse-
quent deletion of closely related or essentially repetitious,
curvilinear, or generic combinations of characters.) “The
compared samples may be considered as drawn from the
same or from different populations. One of the alternative
conclusions (drawn from the same or different popula-
tions) is chosen from the results of a t-test at an appropriate
level of significance.
In Noetia (Eontia) spp. the level of significance is
taken at 10°
O°
two-sided level is used. The higher level is used for Noetia
two-sided. In Glycymeris and Anadara a 5%,
(Eontia) because the species are successional, i.e. closely
related species in a nearly continuous depositional se-
quence. However, comparisons of species of this subgenus at
the 109% and 59% levels of significance do not give different
interpretations for the identity of species, but the higher
level (10°%) shows successional relations better because it
allows smaller differences to be considered as significant.
Hence while no differences may be manifest in a group of
samples at the 5% level, the 10° level may show differences
for some samples and none for more closely related samples.
The following notes pertain to the characters chosen
which are measured on a single valve of one specimen.
Length (Lt) is the maximum anterior posterior dimension.
Height (Ht) is the maximum dorsoventral dimension. The
width of the ligamental area (WI) is measured along a line
perpendicular to the hinge line from the highest point of
the ligamental area to the lower limit of the ligamental area.
‘The measurement is along the slope of the ligamental area
and is, therefore, not the height of the ligamental area.
Ligamental area length (LI) is measured from the anterior
to the posterior ends of the ligamental area and is the
maximum value of this feature. The convexity of a valve
(C/2) is determined by an outside caliper measurement
in which one jaw of the calipers is set on the dental plate,
and the other jaw is set on the point of maximum gibbosity
on the valve exterior. Hence the actual curvature of the
valve is not recorded but only its width (thickness of
auctors) .
Combinations involving adductor muscle scars in gen-
eral were not found to be of value for characterization of
species. However, the height of the posterior muscle scar
(HPM), the maximum value measured dorsoventrally,
combined with length was found to be useful in species
of Noetia (Eontia) .
Of the measurements of the dental series investigated,
three were found to be useful. The distance from the an-
teriormost tooth to the beak (Ts-B), measured from the
outermost edge of the anterior tooth to the mid-point of the
beak, is influenced not only by the length of the anterior
dental series but also by the height of the ligamental area
and the height and attitude of the beak. The same is true
for the distance from the outermost margin of the pos-
teriormost tooth to the beak (T,-B). The distance from
the outermost margin of the anteriormost tooth to the out-
ermost margin of the posteriormost tooth (T."T,) is meas-
ured on a straight line between the two teeth. The distance
is influenced by the length of the dental series and by the
curvature of the series. T.-B+T,-B is always greater than
Tea.
SYSTEMATIC PALEONTOLOGY
Class PELECYPODA Goldfuss, 1820
Order PRIONODESMACEA Dall, 1895
Suborder TAXODONTA Neumayr, 1883
Family NUCULIDAE Adams
Genus NUCULA Lamarck, 1799
Nucula proxima Say, 1822
Plate 1, figures la, 1b
Nucula obliqua Say, 1820, Amer. Jour. Sci., vol. 2, p. 40 (on Lamarck,
1819).
N. proxima Say, Say, 1822, Acad. Nat. Sci. Philadelphia, Jour., vol. 2,
1st ser., p. 270.
Diagnosis.—Shell subovoid to subtrigonal; hinge highly
arched; anterior teeth more numerous than posterior and
with larger members, posterior series about one-half as long
as anterior; resilifer large, producing large edentulous space
under beaks; anterior muscle scar slightly more ventral than
posterior muscle scar; external ornament absent except for
growth lines and faint striae; beaks small; umbos promin-
ent; inner margin finely denticulate ventrally.
20 PALAEONTOGRAPHICA AMERICANA (V, 34)
TABLE 5
Abundance* Chart of Foraminifera Genera from Localities in Table 1
localities
Genera i 2 3} 4 5 6 7 8
No)E abe ey ay ale IG aS aS OD) AO) PL
Family Textulariidae
Textularia 4, 23 Gy eS = = = =
Family Miliolidae
Quinqueloculina 46 7. SS = = S =
Family Nodosariidae
lagena - - - - - - - -
Family Buliminidae
Bulimina - - - - - - - 2
Family Uvigerinidae
Angulogerina - ho es = = © = =
Trifarina - = = = = = =
Uvigerina = = = = = a = =
Family Heterohelicidae
Bolivina - 4 = = = a = =
Family Polymorphinidae
Raphanulina
Guttulina
Polymorphina
Family Nonionidae
H1phidium - - 6 36 20 - 15 Ww
Nonion 9 6
Nonionella - - - - - - -
~
o
=
°
2)
5s
'
~
al
to}
Family Cassidulinidae
Cassidulina - - = = = = = =
Family Rotalidae
Cancris -
Cibicides 25
Discorbis
Eponides
Ammonia ("Rotalia'') - - 2 -
tn
1
wo
WWOannD
1
=
jo)
ny
Family Orbdulinidae
Globigerina 2 - hk 2 abe - -
Orbulina 2 = = = = =
Number of Specimens 8 56 5 62
*Abundance by percent for each locality.
Discussion.—The striation of the inner ventral margin
is the product of fine ribbing under the surface of the
shell. ‘The striae show through the external surface of the
valves, but produce no relief on the exterior. The ostracum
is ridged and grooved toward its lower limit. The extension
of these undulations produce the denticles on the ventral
margin. ‘The nacreous layer is concomitantly undulated
with the ostracum. The undulations fade from the ventral
margin and disappear dorsally. ‘The innermost laminae of
the nacreous layer are not undulated. Hence suggestion of
striations can be seen in exterior (especially) or interior
views but produce relief only on the ventral margin in the
form of small denticles.
Ss Wo =. Ss (ee eke Ao bo Se ah 5}
- 16)" 2 =P = Gs 2 3G A) o 2
- - - - - - - - - 10 6 = -
— 6, a0) = 2 - 6. Se is
= a = = = 9) = = = = oa = =
= hie Stree = one De,
= - - 2 - 2 2° = tae 1) = oe =
ca = = = 2) = = = = = QB os Ss
- oS = = 2 2 - ee
- Gu) 12 20 oe ee SS = ee
- Uigy Ke) Sk sy A alisy A SIS} ah Gy 25 AS
= fs eS = 5 Loe ages 1g = - 6 8
= = = = = - = - = = = = k
= = 2 = 2 = = = = = = = =
- BT 9h ILO i Ae alg aly ass lS) 3B
= 6 Ci ake #4) Se ae ee 1 wal 32
= - 2 7 A c= 10) ease
- 1 ; 6 A bh 2 MS GS 10
Say (1822, p. 270) stated that Nucula proxima differs
from N. nucleus Linné, 1758, the type species of the genus,
in being wider and having the posterior series of teeth more
regular and distinct.
According to Abbott (1954, p. 331), N. proxima ranges
from Nova Scotia to Florida, and west to ‘Texas, and is com-
mon just offshore in mud. However, Parker (1956, p. 347)
reported that the species is commonly collected offshore
(13-50 fathoms) in the Gulf of Mexico.
Hypotype.—U. N. C. Cat. No. 3511.
Range.—Miocene-Recent.
Localities.—Nos. 6, 7, 8, 13, 14, 18, 21, 22 (see Register
of Localities) .
Mip-ATLAN TIC
Family NUCULANIDAE Stoliczka, 1871
Genus NUCULANA Link, 1807
Subgenus SACCELLA Woodring, 1925
Nuculana (Saccella) acuta (Conrad), 1831
Plate 1, figures 2a, 2b
Nucula acuta Conrad, 1831, Amer. Marine Conchology, p. 32, pl. 6,
fig. 1 (non J. de Carle Sowerby, 1840, Geol. Soc. London, Trans.,
2d ser., vol. 5, pl. 39, fig. 5); Conrad, 1845, Fossils of the Medial
Tertiary of the United States, p. 57, pl. 30, figs. 2; Gardner, 1943,
U. S. Geol. Sur., Prof. Paper 199-A, p. 19, pl. 1, figs. 1, 2, 4, 5.
Leda acuta Dall, 1898, Wagner Free Inst. Sci., Trans., vol. 3, pt. 4,
pp. 592, 593.
Diagnosis.—Shell slightly gaping posteriorly, anterior
margin gently rounded, posterior margin acute, rostrate;
hinge arched; teeth chevron-shaped, anterior series of teeth
subequal to posterior series; external ornament of numer-
ous, small, concentric ridges regularly to irregularly spaced;
beaks tiny, opisthogyre; inner margin smooth.
Discussion.—The nearshore and offshore variations
observed by Parker (1956, pp. 329, 317) were not definitely
discernable. The specimens collected have the closely spaced
concentric ridges of the offshore type, however, these ridges
were more prominent than in the one figured by Parker
(pl. 2, figs. 8a, b). The offshore form is reported by Parker
from depths of 13-50 fathoms. The range of Recent repre-
sentatives is from Cape Cod to the West Indies (Abbott
1954, p. 338).
Gardner (1926, pp. 11-20) described several new
species of Nuculana trom the Alum Bluff groups of Florida.
Distinction is based on small differences in spacing of the
concentric. The following species of Gardner of lunule and
escutcheon. ‘The following species of Gardner (1926) are
probably conspecific with Nuculana acuta, but lack of type
material has precluded final judgment: Leda leptalea, Leda
polychoa, and Leda proteracuta.
Hypotype.—U. N. C. Cat. No. 3512.
Range.—Miocene—Recent.
Localities.—Nos. 2, 6, 7, 8, 13, 14, 17, 18, 19.
Genus YOLDIA Moller, 1842
Yoldia laevis (Say), 1824
Plate 1, figures 3 & 4
Nucula laevis Say, 1824, Acad. Nat. Sci. Philadelphia, Jour., 1st ser.,
p. 141, pl. 10, fig. 5.
Yoldia laevis Dall, 1898, Wagner Free Inst. Sci., Trans., vol. 3, pt. 4,
p. 596.
Diagnosis.—Shell elongate, small, with distinct posterio-
dorsal fold, gaping anteriorly and posteriorly; hinge gently
arched; anterior series of teeth subequal to posterior series,
most members chevron-shaped; resilifer large, nearly round;
ormament of growth lines only; beaks small, subcentral,
tilted posteriorly; inner margin smooth.
PeRTIARY ARCACEA: BirD iz
Discussion.—Yoldia limatula Say, 1831, of the Pleisto-
cene and Recent is closely related to Y. laevis. Dall (1898,
p. 596) considered the two distinct and stated that Y. laevis
has larger chondrophores, smaller and more numerous
teeth, more pointed posterior end, and_ less compressed
escutcheon.
Hypotypes.—U. N. C. Cat. Nos. 3513, 3514.
Range.—Calvert-Yorktown Miocene
Localities.—Nos. 9, 12, 18.
Suborder PRIONODONTA MacNeil, 1937
Superfamily ARCACEA Lamarck
Family ARCIDAE Lamarck, 1818
Diagnosis.—Equivalve or not; inequilateral; ligament
usually duplivincular, prosodetic, amphidetic, opisthodetic
or confined to a pit under the beaks; ligamental area orna-
ment variable; pallial line complete; adductor muscle scars
subequal; teeth taxodont, variable in shape and orientation,
rarely parallel to the hinge; dental plate sublinear; costae
usually present; beaks prosogyre, orthogyre, or opisthoeyre;
crenulations present or absent.
Range.—Triassic? Jurassic? Cretaceous-Recent.
Qualitative considerations —Assigning an arcid species
to a subfamily, without first determining the genus, is dif-
ficult at the present time. During this study, few members
of the subfamily Arcinae could be obtained. This group was
studied mainly by the use of illustrations and descriptions.
Some of the more typical representatives are included in
the statistical study of the group which follows on the next
few pages. Qualitatively, some of the features that have
been used and some that may be used to separate the sub-
families are:
1. Ornamentation of the ligamental area.—The Noeti-
inae are partly characterized by prominent vertical grooving
on the ligamental area. This feature is by no means re-
stricted to the group. In some cases, especially in Arca, s.s.,
Lunarca, and Noetia, the vertical striae are related more or
less directly to the taxodont dentition. Extending from the
teeth onto the ligamental area are ridges between which are
grooves. Vertical ligamental area ornamentation is more
prominent in the Noetiinae than in other groups and can
be used to recognize that subfamily. Interestingly, weather-
ed individuals of species of Anadara have been found with
prominent striations on the ligamental area. Dilute HC]
can be used to bring out the vertical striae on unweathered
specimens. Apparently a thin veneer of calcium carbonate
is secreted over the ligamental area by the mantle at suc-
cessive growth stages. The teeth, having formed continu-
ously, assert themselves in the shell structure to a greater
99 PALAEONTOGRAPHIC
degree than the calcification associated with the ligament.
As a result, the underlying striae caused by teeth are ex-
posed on weathering of the shell. A similar phenomenon
may be observed in gerontic and weathered individuals of
Glycymeris. Again the striae are apparently related to the
cdlentition.
The chevron-shaped surficial markings in the liga-
mental area of Anadara seem to be different than the analo-
gous or homologous structure in the Arcinae. In Anadara,
the chevrons impose a terracing on the ligamental area
whereas in the Arcinae they seem to occur as actual grooves.
2. Costac.—The nature of the costae seems to be useful
in separating the Anadarinae, though some overlap exists
with the Arcinae. In the Arcinae the ribs are mainly small,
rounded, and sinuous, and riblets are commonly present;
in the Anadarinae the ribs are prominent, flattened, not
sinuous, and riblets are rarely present.
3. Crenulations and shell structure.—Those forms with
crenulations apparently possess them as a result of the con-
tinuous growth of the ribs. Ventrally, flexing in the area of
the ribs is present throughout the shell. Sections cut more
toward the dorsal edge of the valve show that the ribs do
not extend through the entire shell thickness indicating that
the mantle has secreted an additional amount of calcium
carbonate so that undulations exist only at the ventral mar-
gin in most species. The Noetiinae and Anadarinae have
prominent crenulations; the Arcinae do not have any, as a
rule, and the ribs in thin section are superficial and are
restricted to the outer part of the shell. Flexing of the
laminae was not observed in the members of the Arcinae
examined (see Plate 6) .
|. Byssal gape.—Arca, s.s. and some species of Barbatia,
s.§. have a ventral gape to make room for the protrusion of
the strong byssus. Arca seems to always possess this feature,
but Barbatia does not. It, therefore, is not reliable fox
identification. Further, if the gape is not large, both valves
are necessary to observe it. Reinhart (1935, p. 15) stated the
byssal gape is characteristic of the Arcinae, but he included
forms in the category which do not have the gape.
Quantitative considerations—To test the systematic
relations of generic and subgeneric categories, 45 characters
were selected and measured (or observed in the case of
qualitative characters) on two typical species of each of 15
genera and subgenera of the Arcacea. The species in every
case were represented by a single, typical, mature individual
which seemed conspecific with the type. These species are
listed in Table 6. Illustrations and descriptions were used
when a species to be studied was not available for first hand
"A AMERICANA (V, 34)
study. The data were then analyzed by the Rogers and
‘Tanimoto (1960) method. Matrix 2 contains the match
coefficients of species. In this study Barbatia (Barbatia)
reeveana (Reinhart) (=Cucullaearca reeveana Reinhart,
1943) emerged as the prime node, 7.c. as the most typical
species of those investigated. This means that this species
has more characters in common with the other species
studied than any other in the matrix. The typicality rating
of the whole group is shown in ‘Table 7. Table 8 shows the
clusters formed by the analysis. A cluster is defined as a
group of individuals which have dj,; spacings sufficiently
equal to allow the equation U,=I—En/,.n to become as
small as desired (i.e. to reach the least random state) . See
Glossary of Statistical ‘Terms for definitions of symbols. A
cluster was allowed when upon the elimination of the most
atypical case, the resulting U,, value was not decreased.
Conclusions.—l. Cluster 1 shows the Barbatia tribe
bonded. Some of the generic names are considered distinct,
others not. Those retained as valid are those which have
characters readily distinguishing them from all others. (If
a cluster consists of forms not readily distinguished, the
forms comprising the cluster are treated as belonging to
one genus or subgenus.) Representative species of the first
cluster belong to the following supraspecific categories:
Arcopsis von Koenen, 1885; Barbatia, s.s. Gray, 1842; Acar
Gray, 1857; Obliquarca Sacco, 1898; Calloarca Gray, 1857;
Cucullaria Conrad, 1869; Cucullacarca Conrad, 1865. Acar,
Obliquarca, and Calloarca are included as subgenera of
Barbatia in keeping with the general practice of authors
because they cluster well with each other and with Bar-
batia. Dall (1898, p. 615) suggested Plagiarca and Polyne-
ma Conrad, 1875 be placed with Calloarca. Cucullacarca is
put in synonymy with Barbatia, s.s. Reimhart, 1935, consid-
ered Cucullacarca as distinctly characterized by the large
byssal gape—a variable feature. Heath (1941) found no
anatomical distinction between the Recent species of Bar-
batia, s.s. and Cucullacarca that he investigated.
2. Clusters 2 and 5, which share several forms, group the
Anadara tribe. Because fossil species of Anadara Gray, 1847,
Scapharca Gray, 1847, and Granoarca Conrad, 1863 can not
always be distinguished, it is suggested that forms previously
assigned to these categories be placed under Anadara in
keeping with the law of priority. Granoarca has often been
considered a subgenus of Barbatia; no evidence for this sup-
posed relation was established here.
Cunearca Dall, 1898 is considered a subgenus of Ana-
dara because it is obviously closely related in form and
anatomy (Heath, 1941) and may be identified from one
MATRIX 2
Match Coefficients for Thirty Arcid Species in Table 6
Specimen no. 2 3 4 5 6 T 6 9 10 ll 12 13 14 15 16 17 18 1y 20 21 22 23 24 25 26 27 28 29 30
i. 475 .168 =. 216 Ge ee OS OOR rico nolosee meoon) 1GALeea25) = 168) ) ©1184 216 106 Lil 254.216 216 Pil APSE 194.304.2607) .098-—— 046.153 184
2s 153.184 Mie eleoe sLh4e | 206 Toe Oreo ea2oON) BALD 125 168 233 125) Orit 254. 5233 250) 27 Ld 56 ees 250' 7.225 S11 a9 es
30 .475 PRO MeOT I Na2G 267) 4 lies 09% =. 304 267 loon los ieee 111 166 168 yey NG aie 156 21 213) 200) 267, 200 2250) = a250 eae
4, oil 20a 205) 125 139.304 250.216 164 096 [Cees 125 345° Silos 168 120. 3104 104) S285) S285) 2G 250 ee 250m TG
a Hal PE aelare cet 267.304 PY SRI 153.207 184.267). 343, 150. 168 2200) “7276 3254) S45) S66) ee2eo 50) ose elon mend
6. -348) 250) 2304 233, 2343 2233" 1168 168) 2216" 3216 285) 205 276, .250 250 2276) «12540 345m 238 324 200.168 «= 6285S. 250
ie SUC Malo se COMN mnt oN QUAN mo) mooi 200) © 200 233.184 295 .200 .184 .U86 .088 .213 .304 451 216 «=«.216—S 4520S. 285
8. 139° 6139). 304 DOT ICON elena) 680). 276) a e200 200 295.108 =. 200 Wie 04 194 .304 .267 168.216 6343S. 285
9. 576 250 ZION es68)) 2600 2903) 8.285) a24) 2428 254 .324 343) 3483. 3210 7396. F160) 922165 Boa aoe Soe
10. é 210 «.164 «=.400 365. 363 S00) 2304 2451 345 .324 = .205 396 §6©.480 «=.370) = «153. 216 139) S139 eases
ilk, 406.20). 200 200) 233) 2200 206 4u0 210, 184 P5Ge File 23s) ee 40G) 00 200.216.285.385
ee 250 .184 2aay 200 164 250 340 eld) 2267 ney iss} 233) 3.343)" 385, 5153) 200) cOAmee eet
13. Sop0n) 205) sesue 267 =. 385 Pe) arelerg Ae Pr SBE 254) 2104) 7216 3233 2250) [200 sree
14. 250) 2285 3267 1342 Ry | BRP Neneh Sah Gy ap} 233) 153.9. 200) 2267, =-250)8 e1oG enn
15, 500 426 .324 298 .385 .428 295 .293 .396 .184 .216 Ll 2098) “0537 2233
16. . 265 365 .296 .363 .304 321 .370 276 184 216 «=©.084 = .098 184 267
Te 426 295 “aog jaua <del, .206 542 = .108—.216 Ur Te a9) ee
18. O76 226% 2304 345) o70 423 139 216 Le VS125)" S25 ess
19. 09 2327 3213 3223 345 2320 3296)" 293. 2298, “27608 core
20. AGB) BEN YE eae aula) 168 = .153 BRS artis)
21. SaLOn Selene 168 139 DY «098. S39) S039
22. 162" (52968) abe oad 104.086) 088-121
23. . 345 104 121 12m 3104) ) 20887 © eis
24. 175 194.138 «©6138 = .104s 194
25. -406 1)» STG s6amereaes
26. S216" 200be Shomer
27. .007. .267 = .200
28. <200; 2139
29. 385
Mip-ATLANTIC ‘TERTIARY ARGACEA: BIRD 20
valve—the ligamental area lacks the chevron markings pres-
ent in Anadara. Also the posterior dental series is commonly
shorter than the anterior series unlike typical Anadara.
3. Noctia (Eontia) bonds to the Anadara tribe in clus-
ter 4. Species of Noctia have well-formed costae and crenula-
tions which anadarids also possess but barbatids lack. How-
ever, Heath (1941, p. 291) found that N. (£.) ponderosa,
the only species of the genus investigated by him, is anatom-
ically distinct from other arcids that he studied. ‘Though
MacNeil (1958) elevated Noetia and genera he considered
closely related to Noctia to family status, the group is treat-
ed as a subfamily here, as was done by Reinhart (1945) .
The relations of forms considered as noetids by MacNeil are
debatable.
4. One species of Lunarca bonds to the Anadara tribe
(cluster 3). The true relation of the genus to other arcids
is a problem; Heath (1941) also found that Lunarca
(=Argina of auctors,a homonym) did not fit well into one
of the major arcid groups. For convenience, it is placed
with the Anadarinae, as is done by Reinhart (1915). The
classification is supported by the nature of the costae and
crenulations.
5. Surprisingly, the two species of Arca, s.s. studied are
atypical. They bonded to no other group throughout the
study. Hence whether the genus should be so closely placed
to Barbatia (which has been done mainly on the basis that
both have a strong byssus) seems open to debate.
6. The two species of Glycymeris are the most atypical
of all arcids studied, thus supporting the placement of
Glycymeris into a separate family of the Arcacea. Heath
stated that the relation of Glycymeris to the other arcids is
obscure.
7. The new genus and subgenera described by Dall,
etal. (1938) from Hawaii are not included in the quantita-
tive study. Tentatively, it appears that Barbarca, a subgenus
of Calloarca, should be suppressed. It differs from typical
Calloarca only in the nature of the periostracum. A barbatia
was used by Dall as a subgenus of Barbatia from which it
differs in having a smooth rather than having a fringed
periostracum. The nature of the periostracum certainly
would have little application among fossils species, unless
it could be correlated with some other difference. Some of
the forms assigned to Hawaiarca seem to belong to Cal-
loarca, but further study is needed to show the true position
of Dall’s proposed genus.
The two subgenera of Anadara proposed by Gray
(1857, p. 371) , Cara and Rasia, were based on differences in
the periostracum. As defined, these subgenera have no ap-
plication in paleontology and perhaps no more than spe-
cific significance in Recent counterparts.
Table 6
Species used for Statistical Analysis of Arcids*
Specimen No.
1. Arca cf. A. umbonata Lamarck, 1819. Recent.
2. Arca wagneriana Dall, 1898. Pliocene
3. Noetia (Eontia) ponderosa (Say), 1822. Recent.
!. N. (E.) limula (Conrad) , 1832. Pliocene.
5. Lunarca ovalis (Bruguiére) , 1789. Recent.
6. L. brevifrons bucaruana (Sheldon and Maury), 1922.
Recent.
7. Anadara (Cunearca) inconqrua (Say) , 1822. Recent.
8. A. (C.) scalarina (Heilprin) , 1887. Pliocene.
9. Acar reticulata (Gmelin), 1791. Recent.
10. A. reinharti Effinger, 1938. Oligocene.
11. Barbatia (Granoarca) virginiae Dall, 1898. Miocene.
12. B. (G.) propatula (Conrad), 1843. Miocene.
13. Arcopsis adamsi Dall, 1886. Recent.
Id. A. solida (G. B. Sowerby, I), 1833. Recent.
15. Barbatia (Barbatia) lurida (G. B. Sowerby, 1), 1833.
Recent.
16. B. (B.) landesi (Weaver and Palmer) , 1922. Eocene.
17. Barbatia (Calloarca) alternata (G. B. Sowerby, 1),
1853. Recent.
18. B. (C.) leonensis Mansfield, 1932. Miocene.
19. Barbatia (Cucullaearca) recveana (dOrbigny), 1846.
Recent.
20. B. (C.) inusitata Woodring, 1925. Miocene.
21. B. (C.) mississippiensis (Conrad) , 1848. Oligocene.
22. Barbatia (Obliquarca) dentera Woodring, 1925. Mio-
cene.
25. B. (O.) modiolida Woodring, 1925. Miocene.
24. Barbatia (Cucullaria) taeniata Dall, 1898. Pliocene.
25. Anadara (Scapharca) licnosa (Say), 1832. Pliocene.
26. Anadara (Scapharca) transversa (Say), 1822. Recent.
27. Glycymeris subovata (Say), 1824. Miocene.
28. G. americana (Defrance), 1829. Pliocene.
29. Anadara (Anadara) trilineata calcarea (Grant and
Gale) , 1951. Pliocene.
30. A. (A.) formosa (G. B. Sowerby, I), 1883. Recent.
*The forms in this list are recorded here as they have most
recently been known in the literature, or as they have been put into
superspecific categories based on the original definition of that cate-
gory. Synonyms are not applied here but are in the text where they
are discussed in relation to the quantitative analysis made on the
supraspecific categories. The species name is followed by the epoch
from which the type was described or also from which the species is
best known. The known time range is not given.
PALAEKONTOGRAPHICA AMERICANA
‘Table 7
Typicality Ratings of Arcid Species from Matrix. 2
Sum of
Rank Specimen Match Coefficients
| 19 8.410
2 1] 7.941
3 24 7.925
| 10 7.907
5 i) 7.766
6 26 7.718
7 2] 7.684
8 16 7.685
9 20 7.642
10 18 7.534
1] 6 7.467
12 13 7.462
15 15 7.456
14 17 7.388
15 7 7.263
16 14 7123
17 22 7.069
18 12 7.050
19 23 6.920
20 5 6.778
21 8 6.547
22 25 6.510
23 30 6.452
24 29 6.337
25 3 6.058
26 A 6.047
27 I 5.521
28 2 5.377
29 28 5.229
30 27 5.200
Table 8
Clusters Formed by Analysis of Matrix 5
ho
19, is added here with the other species of Cucullaearca
(=Barbatia). Also specimen 10, which is most closely
bonded to specimen 9, is added here.
Numbers 7, 12, 26, 29, 30. U,—0.011.
7, 8, 11, 26, 29. U,—0.010.
Numbers 3, 4, 7, 8, 11, 12, 25, 26, 28, 29. U,—0.020.
Numbers | and 2.
Numbers 6,
Species that failed to cluster: 5, 27.
12
(V, 34)
*KEY TO UPPER TERTIARY ARCIDS OF MID-
ATLANTIC COASTAL PLAIN
Costae superficial, commonly sinuous and rounded;
crenulations absent or poorly defined. (ARCINAE) 2
Costae well developed, relatively straight; crenula-
tions prominent Pay)
Shell small; muscle scars elevated; ligament in tri-
angular pit under beaks—Arcopsis .. . [Arcopsis
(Arcopsis) adamsi]
Shell large; muscle scars elevated; ligament amphi-
detic not confined to pit under beaks .
[Striarca centenaria]
. Striarca
Shell not suborbicular |. aed
Shell suborbicular. (GLYCYMERIDAE) 17
Ligamental area not or only faintly striated verti-
cally; riblets rarely present in interspaces. (ANA-
DARINAE) 5
Ligamental area strongly striated vertically, riblets
always present in interspaces. (NOETIINAE) —
Noctia (Eontia) — 12
Ligament amphidetic . . . Anadara 6
Ligament opisthodetic . . . Lunarca [Lunarca ovalis]
Ligamental area with chevron-shaped grooves—A na-
dara 5.5. 7
Ligamental area without chevron-shaped grooves
. Anadara (Cunearca) .. . [Anadara (Cune-
arca) incongrua |
Costae not multiple 8
Costae multiple 1]
Costae numerous, distinct—Anadara (Anadara)
transversa
Costae few, prominent 9
Shell small, ribs not markedly flattened
A. (A.)_ silverdalensis
Shell large, ribs markedly flattened 10
Shell high A. (A.) carolinensis
Shell elongate A. (A.) propatula
Ribs abundantly nodose; shell subquadrate
A. (A.) callicestosa
Ribs sparsely nodose, shell elongate
A. (A.) lenosa
Costae divided only posteriorly 115)
Costae divided nearly across entire shell 15
Beaks not subterminal, ‘lirations present 14
Beaks subterminal, lirations absent
Noetia (Eontia) incile
Umbos not high, shell rhomboidal
N. (E.) trigintinaria
Umbos high, shell trigonal N. (E.) ponderosa
Mip-ATLANTIC TERTIARY ARGCACEA: Birp 25
15. Ventral sag present N. (E.) limula
Ventral sag absent 16
16. Beaks subcentral in relation to length of shell, an-
terior teeth not L-shaped N. (E.) carolinensis
Beaks anterior in relation to length of shell, ante-
rior teeth L-shaped N. (E.) platyura
17. Costae with fine striations 18
Costae without fine striations 21
18. Striations poorly defined, costae indistinct 19
Striations well defined, costae distinct 20
19. ‘Teeth present in center; shell small, orbicular; liga-
mental area with distinct chevron-shaped grooves
Glycymeris anteparilis
Teeth absent in center; shell large, high in relation
to length; chevron-shaped ornament of ligamental
G. parilis
20. Teeth large and widely spaced in relation to size
area poorly developed
of shell G. lentiformis
Teeth small and closely spaced in relation to size of
shell G. americana
21. Shell subovate, costae strong G. subovata
Shell trigonal, costae very strong G. pectinata
*Where only one species was studied in a genus, the characters
are keyed only to the genus. The bracketed species follows the gen-
eric name.
Subfamily ARCINAE
Diagnosis.—Strongly to slightly inequilateral, equival-
vular or inequivalvular; byssus present, byssal gape strong,
moderate, or absent; ligament amphidetic, opisthodetic, or
confined to triangular pit beneath beaks; ligamental area
narrow to wide, nearly flat to nearly vertical, ornament
variable; costae often sinuous, rounded, poorly developed,
riblets usually present in interspaces; adductor muscle scars
elevated or not; teeth variable, seldom with well-developed
chevron-shaped members; inner margin seldom crenulate.
Range.—Cretaceous-Recent.
Discussion.—According to Reinhart (1943, p. 11) some
representatives of the Arcidae are known from the Jurassic
and possibly the Triassic. The Arcinae are known from the
Cretaceous.
Genus ARCOPSiS von Koenen, 1885
Subgenus ARCOPSIS von Koenen, 1885
‘Synonym.—Fossularca Cossmann, 1887, Cat. illustré
des coquilles fossiles ’Eocéne des environs de Paris, vol. 2,
p. 142.
Diagnosis.—Equivalved, inequilateral, subquadrate; bys-
sal gape absent; ligament confined to small triangular pit
under the beaks; ligamental area finely striate vertically;
ribs fine, rounded, strongly beaded, subequal throughout
valves, tending to be straight; anterior and posterior ad-
ductor muscle scars elevated; ventral crenulations absent;
beaks subcentral, nearly orthogyre; teeth convergent, absent
under beaks.
Discussion.—Arcopsis (Arcopsis) differs from Acar
Gray, 1857 mainly in the nature of the ligamental area. In
Acar, it is strictly opisthodetic and not confined to a pit.
Type species.—Arca limopsis von Koenen, 1885, sub-
sequent designation Reinhart, 1935.
Range.—Danian-Recent.
Arcopsis (Arcopsis) adamsi (Dall), 1886
Plate 1, figures 7, 8
Arca caclata Conrad, 1845, Fossils of the Medial Tertiary of the
United States, p. 61, pl. 32, fig. 2 (non Reeve, 1844).
Barbatia (Arca) caelata Conrad, Conrad, 1863, Acad. Nat. Sci.
Philadelphia, Proc. p. 580.
Arca adamsi Dall, 1886, Harvard Coll. Mus. Comp. Zoology, Bull.,
vol. 12, p. 243.
Arca (Acar) adamsii Dall, Smith, 1888, Linnaean Soc. London, Jour.
Zoology, vol. 20, p. 499, pl. 30, figs. 6, 6a.
Barbatia (Fossularca) adamsi (Dall), Dall, 1898, Wagner Free Inst.
Sci., Trans., vol. 3, pt. 4, p. 629; Gardner, 1926, U. S. Geol. Sur.,
Prof. Paper 142-A, p. 28, pl. 5, figs. 1-4.
Arcopsis adamsi (Dall), Abbott, 1954, American Seashells, p. 344, fig.
26b.
Diagnosis.—Shell small, subrhomboidal; beaks small,
orthogyre; muscle scars only slightly elevated; umbos prom-
inent, slightly inclined anteriorly; umbonal ridge sharp;
hinge line straight, parallel to ventral margin; teeth large
in relation to shell; costae thin, thickened with large tear-
shaped nodes where crossed by growth lines; inner margin
nearly smooth.
Discussion.—This species undoubtedly has a wider dis-
tribution than the three localities from which it was collect-
ed but because of its small size it would tend to be over-
looked. Dall (1898, p. 629) reported its occurrence in Dup-
lin County (Miocene), North Carolina, and stated its pres-
ent range as Cape Hatteras to Brazil in water from 5-116
fathoms deep.
Acar reticulata (Gmelin) , 1791 is similar in shape, size,
and ornament to Arcopsis (Arcopsis) adamsi, but in Acar,
the ligament is posterior to the beaks. Also Acar reticulata
has a sharper umbonal ridge, a wider umbonal area, teeth
continuous under the beaks, and faint striations on the
inner margins of the valves.
Dall (1898, p. 629) attributed the specific name adamsi
to Shuttleworth by Smith, 1888 (op. c7t.). Dall himself
briefly described the species (1886, p. 243). Because Dall’s
description precedes Smith’s, Dall is the author although
the description by Dall is not good.
Hypotypes.—U. N. GC. Cat. Nos. 3515, 3516.
Range.—Miocene—Recent.
26 PALAKONTOGRAPHICA AMERICANA (V, 34)
Localities.—Nos. 2, 3 and 4.
Genus STRIARCA Conrad, 1863
Synonym.—Breviarca Conrad, 1873.
Diagnosis.—Inequivalve, inequilateral, subrhomboidal;
ligament amphidetic; ligamental area vertically striate; ribs
rounded, faintly to strongly developed, somewhat beaded,
subequal in weight throughout, sinuous; anterior and pos-
terior adductors elevated; teeth posteriorly anteriorly con-
tinuous, nearly perpendicular to hinge under beaks, con-
vergent toward extremities; beaks subcentral, orthogyre;
crenulations absent or tiny.
Discussion.—The similarity of Striarca and Arcopsis has
been noted by Gardner (in Stephenson, 1923, p. 109) and
by Rost (1955, p. 192). The present writer also observed the
affinity independently upon observation that both have
vertically striated ligamental areas, elevated anterior and
posterior adductors, and cancellated to beaded radial ribs.
The distinguishing feature is the nature of the ligament
which is confined to a pit in Arcopsis.
Type species.—Arca centenaria Say, 1824, original des-
ignation,
Range.—Cretaceous-Recent.
Striarca centenaria (Say), 1824
Plate 1, figures 6a, 6b
Arca centenaria Say, 1824, Acad. Nat. Sci. Philadelphia, Jour., 1st
Sem, vol 4. ps 138) ply 10), fies 2:
Striarca centenaria (Say), Conrad, 1863, Acad. Nat. Sci. Philadelphia,
Proc., p. 290.
Arca (Barbatia) centenaria Say, Glenn, 1904, Geol. Sur. Maryland,
Miocene, p. 391, pl. 106, figs. 5, 6.
Diagnosis.—Shell subquadrate, ventral margin slightly
indented; beaks small, orthogyre, subcentral; muscle scars
markedly elevated, extending obliquely dorsally to um-
bonal area; hinge line straight, not parallel to ventral mar-
gin; teeth perpendicular to hinge under beaks and towards
margins becoming convergent, usually hollowed by weather-
ing; costae irregular in weight, rounded, slightly sinuous,
some interspaces with riblets; inner margin finely marked,
not truly crenulate; fine striae present inside shell.
Discussion.—No representatives of this species have
been found in the St. Marys formation though rare individ-
uals have been taken from the Choptank and Calvert forma-
tions. ‘The species is common in the Yorktown formation of
Virginia. It was not collected south of Courtland, Virginia.
It is not clear why the range is so limited. To my knowl-
edge, no Striarca has been found in the Atlantic Coastal
Plain deposits in the interim from Upper Cretaceous to Cal-
vert time.
Hy potype.—U. N. C. Cat. No. 3517.
Range.—Calvert-Yorktown Miocene.
Localities.—Nos. 19, 20, 21, and 22.
Subfamily ANADARINAE Reinhart, 1935
Diagnosis.—Shell slightly to strongly inequilateral;
equivalve or not, when inequivalve left valve always the
larger; byssal gape absent or small; ligament amphidetic or
opisthodetic; ligamental area high to low, gently sloping to
nearly vertical, markings variable; hinge line straight to
broadly arched; costae well developed, often flattened, not
sinuous, interspaces rarely with riblets; adductor muscle
scars not elevated; ornament of two valves discrepant or
not; teeth often divergent near center and convergent to-
ward extremities, some teeth chevron-shaped; inner margin
strongly crenulate.
Discussion.—Some students of the arcids feel that the
absence of the byssal gape is the main method of distin-
guishing this subfamily from the Arcinae. This absence is
not, however, consistent. Some members of Barbatia have
small byssal gapes or have none at all. Unfortunately, even
if the gape is present, the species possessing the gape is sel-
dom figured in such a way as to illustrate the feature. The
following characters of the Anadarinae may be used to dis-
tinguish them from the Arcinae: the adductor muscle scars
are never elevated, the costae are usually flattened rather
than rounded and are never sinuous in outline, the inner
margins are coarsely crenulate, and ribs are accompanied by
flexing which extends deep in the shell (PI. 1, figs. 2, 4, 5, 6) .
Further investigation is needed to show the last character
to be significant. The chevron-shaped ornament of the liga-
mental areas in members of the two subfamilies appears to
be different. In the Anadarinae the ornament occurs as a
sort of terracing—each successive chevron-shaped zone from
hinge toward beak is at a slightly higher level. In Arca, s.s.
the chevron ornament is represented as actual grooves.
Range.—Eocene-Recent.
Genus ANADARA Gray, 1847
Subgenus ANADARA Gray, 1847
Synonyms.—Cara Gray, 1857; Diluwvarca Woodring,
1925; Granoarca Conrad, 1863; Larkina Reinhart, 1935;
Rasia Gray, 1857; and Scapharca Gray, 1847.
Diagnosis.—Equivalve or inequivalve; byssus present
or absent; ligament amphidetic; ligamental area with
horizontal, vertical, and chevron ornament; costae tend to
be flattened, striated or not, smooth or reticulated, riblets
absent in interspaces; ornament of two valves equal or dis-
crepant; crenulations prominent; beaks usually in anterior
one-third of hinge, prosogyre.
Mip-ATLANTIC “TERTIARY ARGACEA: Burp oF,
Discussion.—As described here, Anadara includes Scaph-
arca, Granoarca, and Larkina. Scapharca was erected by
Gray to apply to inequivalved forms with “deeper plaits”’
on the left valve which otherwise are Anadara. This is
usually not of use to a paleontologist because seldom are
fossil pelecypods found with both valves intact. Also the
term “deeper plaits’” apparently meant to connote discrep-
ancy of ornament in the two valves, but some species are
inequivalve but have equal ornament. Heath (1941, p. 303)
studied the soft parts of several representative species of
the arcids, including species referred to Anadara and
Scapharca. He found essentially no anatomical differences
in the two. In the statistical study presented earlier in this
paper, no morphologic differences asserted themselves so
as to make the two separable. Because Scapharca, as original-
ly defined, is only a special case of Anadara and because the
name Anadara precedes the name Scapharca in Gray's 1847
paper, the genus Anadara is employed here as was done by
Reinhart (1935, 1943), who used Scapharca as a subgenus
of Anadara. Dall (1898) employed both terms but used
Anadara as a subgenus of Scapharca, which he thought to
be more widely applicable. Dall (1898, p. 619) stated that
the transition from equivalve to inequivalve is complete;
the same conclusion was reached by Rost (1955, p. 193).
Granoarca was included by Conrad (1863, p. 290) and
Dall (1898, p. 627) as a subgenus of Barbatia. However, the
ribs are straight, flattened, and uniform in weight through-
out; the inner margin is coarsely crenulate, and the liga-
mental area is high and marked by horizontal and chevron-
shaped grooves as in typical Anadara. Statistically, the two
species assigned to Granoarca allied themselves to Anadara.
Larkina was erected to include those species of Ana-
dara with “trigonal” equal valves and with series of teeth
which diverge at the center of the hinge and converge to-
ward the extremities. This is a common occurrence in the
group, but is also variable in that some species show this
trait at one ontogenetic stage and not at another. Because
a species can not change from one subgenus to another in
its ontogeny, this name is dropped. Diluvarca has been sup-
pressed by Woodring himself (1928 p. 18) .
Cara and Rasia Gray, 1857 are based on features of the
periostracum and are of no value paleontologically and
possibly of less than subgeneric value.
Type species.—Arca antiquata Linné, 1758, original
designation,
Range.—Oligocene-Recent.
Anadara (Anadara) silverdalensis (Kellum), 1926
Plate 2, figures 1-3
Arca (Scapharca) silverdalensis Kellum, 1926, U.
Paper 143, p. 34, pl. 8, figs. 1-3.
S. Geol. Sur., Prof.
Diagnosis.—Shell subquadrate, inequivalve; ligamental
area with longitudinal lines and chevron markings, rather
flat, moderately wide; hinge line straight; teeth small, form-
ing a complete series, normal to hinge or slightly divergent
near center, convergent toward extremities in adults; costae
rounded, tending to be nodose, especially on left valve,
usually more narrow than interspaces; sculpture of two
valves slightly discrepant, costae more nodose and flatter
on left valve; umbo and umbonal ridge prominent; beaks
subcentral, slightly prosogyre.
Discussion.—This species is not known outside the beds
at Silverdale (which Kellum correlated with the Trent for-
mation, which he relegated to the lower Miocene) and Hay-
wood Landing where it is common. It was collected from
spoil banks from Gillette’s farm near Silverdale and in place
from Haywood Landing on the White River. Kellum stated
that this species is closely related to Arca carolinensis Dall,
1898 from Duplin County, North Carolina. Anadara
(Anadara) carolinensis is a rare species and seems to be
restricted to the Yorktown formation of Virginia. It is most
likely that Kellum was making the comparison to Anadara
(Anadara) transversa (Say), 1822 which is common at
Natural Well, North Carolina. A. (A4.) silverdalensis can be
distinguished from the species at Natural Well by its fewer,
more prominent costae, more quadrate outline, and_ its
more central beaks. Mansfield (1937, p. 203) stated that his
species, Anadara tarponensis, appears to be closely related
to A. (A.) silverdalensis. The similarity is so great that the
two may be identical.
Hy potypes.—U. N. C. Cat. Nos. 3518-3520.
Range.—Lower Miocene.
Localities—Haywood Landing and Silverdale, North
Carolina.
Anadara (Anadara) callicestosa (Dall), 1898
Plate 1, figures 10a, 10b, lla, 11b
Scapharca (Scapharca) callicestosa Dall, 1898, Wagner Free Inst. Sci.,
Trans., vol. 3, pt. 4, p. 638, pl. 34, figs. 17, 18.
Anadara callicestosa (Dall), Gardner, 1943, U. S. Geol. Sur., Prof.
Paper 199-A, p. 24, pl. 3, figs. 2, 6. _
A. callicestosa wilsoni Gardner, 1943, ibid., p. 24, i, Sy adem ty, OL Iz
A. magnoliana Gardner, 1943, tbid., p. 25, pl. 3, figs. 1, 4, 5, 7.
Diagnosis.—Shell subquadrate, thin; ligamental area
marked with longitudinal lines and cheyron-shaped areas.
low, rather wide; hinge straight; central teeth divergent or
perpendicular to hinge, lateral members convergent in
adult; costae flattened, wider than interspaces, minutely
grooved one to five times so that two to six riblets are
formed ventrally, anterior members rounder, more nodu-
lous than others; interspaces finely and abundantly lirate;
left valve rib complex wider than right, more nodulose;
; ;
28 PALALONTOGRAPHIG
umbonal ridge distinct; beaks just anterior of center; crenu-
lations extend far dorsally, finely striate.
Discussion.—Gardner’s A. callicestosa wilsoni was de-
scribed from a single valve, as was A. callicestosa Dall. Shel-
don (1916, p. 43) had several specimens at hand and stated
that some of these were more ontogenetically advanced than
Dall’s type. These she reported as being more produced
posteriorly, having a wider cardinal area, and more grooves
in the ligamental area. When this variation is considered,
Gardner's subspecies seems to be unnecessary. Similarly, A.
magnoliana was described from a single valve and seems to
be conspecific in all respects except for having three riblets
on the costae instead of typically four.
The sculpture of the two valves of Anadara (Anadara)
callicestosa (judging from figures in Sheldon 1916, pl. 10,
figs. 3, 4, 5) is discrepant. The rib complexes of the left
valve are wider in relation to the interspaces than those
of the right valve. Also those of the left valve are more
prominently nodose, and the nodulose character of the
ribs extends farther posteriorly on the left valve. However,
this observation may not be generally true for the figures
examined are of opposite valves of two individuals. A com-
plete specimen has not been reported. 4. callicestosa cannot
qualify as a Cunearca. Species of Cuncarca are distinct in
that they do not have chevron markings on the ligamental
area.
A. (A.) callicestosa is rare in the Duplin marl at
Natural Well and has not been collected elsewhere during
this study. Besides the Natural Well locality, Gardner (1943,
p. 24) reported the species from Gaskins Wharf, 16 miles
below Suffolk, Virginia, on the Nansemond River.
Hy potypes.—U. N. C. Cat. Nos. 3521, 3522.
Range.—Duplin Miocene.
Locality.—Natural Well, North Carolina.
Anadara (Anadara) lienosa (Say), 1832
Plate 1, figures 5a, 5b
Arca licnosa Say, 1832, Amer. Conchology, pl. 36, fig. 1.
A. secticostata Reeve, 1844, Conchology Iconica, Arca No. 38, pl. 6.
Anomalocardia floridana Conrad, 1869, Amer. Jour. Conchology, vol.
Seip. OSs spl. ds, tiges2.
Scapharca (Scapharca) lienosa (Say), Dall, 1898, Wagner Free Inst.
Sci., Trans., vol. 3, pt. 4, p. 636.
Anadara lienosa floridana (Conrad), Abbott, 1954, American Sea-
shells. p. 344, pl. 27, fig. 0.
Diagnosis.—Slightly inequivalve, strongly inequilateral,
subrectangular, large; ligamental area wide, marked with
longitudinal lines, broad chevron-shaped areas, and faint
vertical striae; hinge line straight, long; teeth in long con-
tinuous series, only last two or three members convergent,
few chevron-shaped; each costa complex larger, smaller, o1
AMERICANA (V, 51)
equal to interspace width, each grooved one or more times,
posterior ones not corded; sculpture of two valves equal;
hinge line and ventral margin subparallel or not; umbonal
ridge greatly rounded.
Discussion.—Recent specimens with brown stain have
been called A. secticostata and without the stain, A. flori-
dana or A. lienosa floridana. Judging from figures and de-
scriptions, there are no morphologic differences in these
forms. Sheldon (1916, p. 37) stated that Recent shells listed
as A. licnosa are A. secticostata which means that she based
the distinction on relative age. No real means of separation
of Recent and fossil forms exist.
Perhaps Arca protracta Rogers and Rogers, 1837
(Gardner, 1943, p. 24) should also be placed here. The
figured specimen (no other specimen has been assigned
to this species) seems distinct. This specimen is lower in
relation to length and is more rounded posteriorly and
anteriorly than A. licnosa. No specimens of A. lienosa show
this variation.
The costae of Anadara lienosa are variable from spect-
men to specimen; each rib is usually grooved once down the
middle. Most costae on adult specimens are multiple. ‘The
grooving disappears toward the umbos and increases in
prominence with ontogenetic development. However, all
specimens (including young forms) observed have multiple
ribs. In addition to the major division of ribs, smaller
grooves appear on some specimens, especially along the
umbonal ridge and become more prominent ventrally.
These secondary grooves are not so deep nor long as the
primary ones and are lateral to the primary grooves. Stull
more division may take place so that ventrally one costa
may be represented by as many as eight riblets. The two
primary parts of the costae may or may not be symmetrical-
ly divided; either the anterior or the posterior one-half may
have more numerous divisions.
Anadara lienosa has not been observed with certainty
farther north than North Carolina. It is rare in the Duplin
formation and is otherwise found only in the Waccamaw
formation in North Carolina. Upper Tertiary representa-
tives are known from Florida. Parker (1956, p. 349) report-
ed that this species is one of those characteristic of the
deep-shelf region in the Gulf of Mexico.
Hypotype.—U. N. C. Cat. No. 3523.
Range.—Yorktown Mrocene—Recent.
Localities.—Nos. 1, 2, and 6.
Anadara (Anadara) carolinensis (Dall), 1898
Plate 1, figures 9a, 9b
Scapharca (Scapharca) carolinensis Dall, 1898, Wagner Free Inst.
Sci., Trans., vol. 3, pt. +, p. 639) pl. 33) tig. 11,
Mip-ATLANTIC TERTIARY ARCACEA: BIRD 29
Anadara carolinensis (Dall), Gardner, 1943, U. S. Geol. Sur., Prof.
Paper 199-A, p. 25, pl. 2, fig. 6.
Diagnosis.—Shell suborbiculate to subquadrate, thick;
ligamental area wide, high, with light longitudinal mark-
ings and heavy chevron grooves; hinge line straight; teeth
nearly perpendicular to hinge tending to become divergent
under beak and convergent at extremities, many chevron-
shaped; costae flat, prominent, coarsely corded by concen-
tric growth lines, some with faint central grooves, costal
width subequal to interspace width; sculpture of two valves
probably equal; beaks of adult subcentral, distinctly pro-
sogyre.
Discussion.—This species is rare and was found only at
Claremont and at Cobham Wharf (about 12 miles below
Claremont) on the James River in Virginia. Dall, however,
reported the species from Duplin County, North Carolina
(1898, p. 640). The fragmentary left valve figured in Dall
does not seem to have a different sculpture from the right
found by me. Until both valves are found intact it can not
be stated whether the species is equivalvular. Anadara
(Anadara) carolinensis seems to be closely related to A.
(4.) idonea (Conrad) , 1832 from the St. Marys formation.
It is difficult to say how important the differences between
the two are because Dall’s species is known from so few
representatives. Tentatively, it may be said that 4. carolin-
ensis has a more quadrate outline, a lower umbonal area,
teeth more strongly chevron-shaped, and _ less distinctly
grooved costae.
Dall (1898, pp. 639-40) attributed Anadara (Anadara)
carolinensis to Wagner, whose specimen Dall used for his
description and figure of the species. According to Dall, fig-
ures of the species were prepared by Wagner, but these were
not published; no description of the species was given in
Waegner’s manuscript. Also Dall noted that Bronn’s refer-
ence (1850, p. 93) to the species is a nomen nudum.
Gardner (1943, p. 25) attributed the name to Wagner
and added her name to the citation but quoted Dall’s de-
scription and used his figure. From Conclusion 28 (Bulletin
of Zoological Nomenclature, vol. 4, 1950, p. 259-60) which
stated:
when a name is validly published in conditions which
satisfy the provisos to Article 25 and the name in
question accordingly acquires the rights under the Law
of Priority and, prior to being so published, that name
had either been published as a nomen nudum or had
been a manuscript name, the name Is to be attributed
to the author by whom it was first published in con-
ditions which satisfied the requirements of the said
provisos to Article 25 and not to the earlier author by
whom it had either been published as a nomen nudum
or had been given currency as a manuscript name.
it is clear that Dall, not Wagner, is the author of the species
Anadara (Anadara) carolinensis.
Hypotype—U. N. GC. Cat. No. 3524.
Range.—Yorktown Miocene.
Locality —Claremont, Virginia.
Anadara (Anadara) propatula (Conrad), 1843
Plate 6, figures la, 1b
Arca propatula Conrad, 1843, Acad. Nat. Sci. Philadelphia, Proc., vol.
1S pes23)
A. propatula Conrad, Conrad, 1845, Fossils of the Medial Tertiary
United States, p. 61, pl. 32, fig. 1.
Barbatia (Granoarca) propatula (Conrad), Conrad, 1863, Acad. Nat.
Sci. Philadelphia, Proc. for 1862, vol. 14, pp. 290, 580.
Barbatia (Granoarca) propatula (Conrad), Dall, 1898, Wagner Free
Inst. Sci., Trans., vol. 3, pt. 4, p. 627.
Barbatia (Granoarca) propatula (Conrad), Mansfield, 1932, Geol.
Sur. Florida, Bull. 8, p. 43, pl. 4, figs. 1-3.
Diagnosis.—Shell elongate, thin, expanded posteriorly,
apparently gaping anteroventrally; ligamental area high to
low, marked with chevron grooves, horizontal lines and
vertical ridges; hinge line nearly straight; teeth numerous
nearly vertical under beaks becoming inclined toward beaks
then away from beaks anteriorly and posteriorly, some
members chevron-shaped, terminal portion of posterior
series with fragmented members; costae flattened, subequal
in width to interspaces, lirae irregularly developed to pro-
duce nodes on ribs, some costae, especially anterior, with
shallow, central groove; ornament of two valves equal;
umbonal ridge indistinct.
Discussion.—Anadara propatula has a distinctive shape.
The posterior expands so that the ventral margin is mark-
edly inclined to the hinge line. The ventral margin is
gently undulated so that an anterioventral gape may have
been present. The probability of a ventral gape has
prompted some workers to refer the species to Barbatia.
As stated above, the gape is not a reliable criterion for
generic determination. The coarse costae and concomitant
coarse crenulations show the species to be an Anadara.
The dental series of Anadara (Anadara) propatula is
likewise distinctive. The teeth of the posterior portion of
the series begin under the beaks nearly vertical to the
hinge, farther out, the teeth become chevron-shaped with
the apex directed inward. Still farther out, the teeth be-
come inclined posteriorly, then bichevroned with the
ventralmost apex directed in and the dorsal apex directed
out. Adult individuals have the terminal members of the
posterior series broken at apices of the dorsal chevrons. Fur-
ther growth produces more fragmentation of the posterior-
most dental series so that a granulose aspect of the teeth
results. A few individuals display similar fragmentation
of teeth in the anteriormost part of the dental series.
Slight erosion of the ligamental area produces vertical
50 PALAEONTOGRAPHICA AMERICANA (V, 34)
ridges on the area. Each ridge can be traced directly to a
tooth from which it originates.
Anadara propatula, though long known from York-
town and Duplin age deposits from Virginia to Florida, is
not commonly collected from these deposits. Recently, sev-
eral specimens of the species have been taken at Rices Pit
near Hampton, Virginia.
Hy potype.—U. S. National Museum, No. 648625.
Range.—Yorktown-Duplin Miocene.
Localities.—Rices Pit, near Hampton, Va. and Ware
River in Gloucester Co., Va., Darlington, S. C.
Anadara (Anadara) transversa (Say), 1822
Plate 2, figures 4a, 4b, 4c 5a, 5b, 6, 7a, 7b, 9a, 9b; Plate 6, figure 5
Arca transversa Say, 1822, Acad. Nat. Sci. Philadelphia, Jour., 1st ser.,
vol. 2, p. 269; Sheldon, Palaeont. Americana, vol. 1, No. 1, p. 47,
pl. 11, figs. 4-6.
A. buccula Conrad, 1845, Fossils of the Medial Teritary of the United
States, p. 60, pl. 31, fig. 4.
A. improcera Conrad, 1845, ibid., p. 60, pl. 31, fig. 5; Sheldon, 1916,
ibid., p. 44, pl. 10, figs. 9-16.
A. aequicostata Conrad, 1845, ibid., p. 60, pl. 31, fig. 6.
A. lineolata Conrad, 1845, ibid., p. 61, pl. 32, fig. 3.
4. plicatura Conrad, 1845, tbid., p. 62, pl. 32, fig. 4; Sheldon, 1916,
ibid., p. 45, pl. 10, figs. 19, 20.
A. brevidesma Conrad, 1845, ibid., p. 62, pl. 32, fig. 5.
A. subsinuata Conrad, 1845, ibid., p. 62, pl. 32, fig. 6; Sheldon, 1916,
ibid., p. 46, pl. 10, figs. 21, 22.
Scapharca (Scapharca) improcera (Conrad), Dall, 1898, Wagner Free
Inst. Sci., Trans., vol. 3, pt. 4, p. 643.
S. (S.) plicatura (Conrad), Dall, 1898, zbid., p. 644.
S. (S.) subsinuata (Conrad), Dall, 1898, tbid., p. 645.
S. (S.) transversa (Say), Dall, 1898, ibid., p. 645.
Anadara transversa (Say), Abbott, 1954, American Seashells. p. 345,
pl. 27, fig. s
Diagnosis.—Shell small to medium large, slightly in-
equivalve, inequilateral; ligamental area marked with faint
longitudinal lines and distinct broadly chevron-shaped
grooves, area narrow to wide; hinge line straight or gently
arched; teeth mainly in a long continuous series, rarely with
edentulous center, portion of series near center nearly per-
pendicular to hinge line, extreme members convergent in
adult individuals, few chevron-shaped members; costae sub-
equal in width to interspaces, a poorly developed, atypical
rib bifurcates in some specimens, anterior ribs tend to be
nodose, those of left valve more so than right, ribs of left
valve more elevated than right; umbonal ridge moderately
to poorly developed.
Discussion.—Conrad’s seven species here referred to
Anadara (Anadara) transversa do not seem to be necessary.
Three of the proposed species at Natural Well grade into
each other completely. ‘The relatively short, high form of
Conrad’s A. buccula could not be statistically distinguished
from the more elongate form which he called A. improcera
(Samples 5 and 6, Table 9). The third species, 4. brevi-
desma, is intermediate between the other two species.
TABLE 9
Comparisons of Regression Coefficients in Anadara*
Sample no. 1 2 3 4 5
ABCD ABCD ABCD ABCD ABCD
2 0000
3 0000 oo000
4 0000 0000 0000
6 0000
1. 0000 0000 0000 0000
W
I
Symbols: A. y
Dey
herpes SHG a = Mbp pe Ie Oy ay SOV, 3
Ht;
C/25 c= T2-T,.
Abbreviations: As in Glycymeris (Table 11)
Significance level 5%, two-sided.
Equations:
Sample no.
1 A. y = 0.687 x = 0.050 Anadara (Anadara) trans-
B. y = 0.076 x - 0.079 versa, Recent, Atlantic
C. y = 0.454 x - 0.051 Beach, N. C.
D. y = 0.465 x - 0.034
2 A. y = 0.647 x - 0.030 A. (A.) transversa,
B. y = 0.102 x - 0.162 Croatan sand, James City
C. y = 0.434 x - 0.080 N.C.
D. y = 0.458 x — 0.065
*Table notation as in Glycymeris analysis (Table 11).
*The first value in each equation is the regression coefficient
(alles slope of regression line). The second value in each equation is
called an &% value, which is the intercept of the regression line on
the vertical y axis of a graph.
Equations:
Sample no.
3 A. y = 0.696 x + 0.191 A. (A.) transversa,
B. y = 0.117 x - 0.079 Waccamaw fm., Town Creek,
C. y = 0.412 x - 0.015 N. C.
D. y = 0.423 x + 0.168
4 A. y = 0.606 x + 0.014 A. (A.) transversa,
B. y = 0.093 x - 0.080 Waccamaw fm., Walkers
C. y = 0.426 x + 0.021 Bluff, N. C.
D. y = 0.362 x + 0.149
5 A. y = 0.547 x + 0.310 A. (A.) transversa,
Be y = 0.078 x - 0.034 (a. buccula” sub-
C. y = 0.387 x + 0.095 set), Duplin marl, Natural
D. y = 0.416 x + 0.096 Well, N. C.
é A. y = 0.618 x + 0.310 A. (A.) transversa
B. y = 0.046 x + 0.009 ("A. improcera"™ subset),
C. y = 0.422 x + 0.035 Duplin marl, Natural Well,
D. y = 0.393 x + 0.031 N.C.
7 A. y = 0.724 x + 0.040 A. (A.) transversa
Be y = O.11k x - 0.059 (undifferentiated sample),
C. y = 0.421 x + 0.013 Duplin marl, Natural Well,
D. y = 0.477 x + 0.030 N.C.
.
.
Mip-ATLANTIC "TERTIARY ARCACEA: BIRD 5]
Probable topotype material of Conrad’s “Arca” sub-
sinuata could not be statistically separated from the other
samples in Table 9 which includes a Recent sample of
Anadara (A.) transversa. Conrad characterized “Arca”
lineolata by its relatively flattened ribs. His A. plicatura is
the same but has more rounded ribs. The slightly larger
left valve of Anadara (A.) transversa has less elevated,
more flattened costae than the right valve, but the degree
of difference is variable in a single sample, and the varia-
tion includes these two species proposed by Conrad. 4.
aequicostata as defined by Conrad includes forms with
slightly grooved ribs. This feature is found developed to
various degrees, probably by weathering.
The similarity of some of the species included in the
synonymy above was recognized by Dall (1898, pp. 643-645)
and more so by Sheldon (1916, pp. 44-47). Anadara (Ana-
dara) transversa shows considerable variation in relative
width of ligamental area, height to length ratio, and nature
of the central members of the dental series. By statistically
comparing the regressions of width of ligament on length
and height on length of the samples in Table 9 no signi-
ficant differences could be found.
Individuals of Anadara (Anadara) transversa from a
given locality may have no central teeth or central teeth
that are perpendicular or slightly divergent to the hinge
line, Lateral members of the dental series are strongly to
weakly convergent.
According to Abbott (1954, p. 345), Anadara (Ana-
dara) transversa ranges from Cape Cod, Massachusetts, to
Florida, and west to Texas, and is common in mud below
low water. Maury (1920, p. 49) stated that the species is
found at depths of 2 to 10 fathoms. Perry (1940, p. 29) re-
ported that A. (A.) transversa is common from the littoral
zone to six fathoms on sandy bottoms.
Hypotypes.—U. N. C. Cat. Nos. 3525-3529.
Range.—Miocene-Recent.
Localities.—Nos. 1-9, 13, 14, 21.
Subgenus CUNEARCA Dall, 1898
Diagnosis.—Inequilateral, valve
larger, posterior margin obliquely truncate; byssus present
or absent; ligament amphidetic; ligamental area with longi-
tudinal grooves and faint vertical striae, never with
chevron-shaped markings; costae of left valve tending to be
nodose throughout, only anteriorly developed in right
valve, riblets in interspaces or not, crenulations prominent;
inequivalvular, — left
beaks subcentral, nearly orthogyre.
Discussion.—The discrepant ornament of the two valves
is readily seen, as it may also be in Anadara s.s The more
reliable distinction between the two subgenera is that
Cunearca does not have the chevron-shaped markings on
the ligamental area which suggests that the ligament is not
duplivincular.
Type species.—Arca incongrua Say, 1822, subsequent
designation Gardner, 1926.
Range.—Oligocene-Recent.
Anadara (Cunearca) cf. A. (C.) incongrua (Say), 1822
Plate 3, figures 2a, 2b; Plate 6, figure 4
Arca incongrua Say, 1822, Acad. Nat. Sci. Philadelphia, Jour., vol. 2,
pt. 2, p. 268; Sheldon, 1916, Palaeont. Americana, vol. I, No. 1, p.
59, pl. 14, figs. 4-7.
Scapharca (Cunearca) incongrua (Say), Dall, 1889, Wagner Free
Inst. Sci., Trans., vol. 3, pt. 4, p. 635.
Diagnosis.—Shell slightly produced posteriorly; liga-
mental area marked with fine longitudinal and vertical
lines; hinge line straight, short; teeth slightly divergent
near center, becoming convergent toward margins, pos-
terior series subequal in length to anterior series; costae
flat, left valve with well-formed nodes throughout, nodes
of right valve developed in anterior one-third and in pos-
terior extremity of valve; umbonal ridge indistinct; beaks
nearly central, orthogyre to slightly prosogyre.
Discussion.—Ywo fragmentary left valves referred to
this species were found at Walkers Bluff and one fragmen-
tary valve was found at Old Dock; no fossil representatives
were found elsewhere. The species is common at Atlantic
Beach near Morehead City, North Carolina, though no live
individuals were collected.
According to an illustration in Sheldon (1916, pl. 13,
fig. 11), the right valve of Anadara (Cunearca) scalaris
(Conrad), 1843 has riblets in the interspaces of the ribs.
The specimen may be an Ad. (C.) scalarina (Heilprin) ,
1887 which is characterized by having riblets in the inter-
spaces of both valves. Ad. (C.) incongrua does not have rib-
lets on either valve. A. (C.) scalaris, described by Conrad
from a single left valve, may be conspecific with A. (C.)
imcongruda.
Hypotype.—U. N. C. Cat. No. 3530
Range.—Upper Miocene-Recent.
Localities—Walkers Bluff and Old Dock, North Garo-
lina.
Genus LUNARCA Gray, 1857
Synonyms.—Argina Gray, 1842; Arginella
1938; and Arginopsis MacNeil, 1938.
Diagnosis.—Inequilateral, equivalvular or inequivalyu-
MacNeil,
lar suboval, highly convex; byssus present or absent; liga-
ment opisthodetic; ligamental area, low, with faint vertical
striae, hinge line gently arched; radial rib flattened, sub-
equal in weight throughout valves, without riblets in
32 PALAEONTOGRAPHICA
interspaces; teeth in two distinct series, the anterior series
short and offset from posterior series, posterior series long,
members in part chevron-shaped; crenulations prominent;
beaks in the anterior one-third of hinge, prosogyre; umbo
prominent.
Discussion.—The generic name Argina is preoccupied
by a lepidopteran insect described by Hibner (MacNeil,
1938, p. 27). Gray described Lunarca costata in 1857 and
stated that the form might be a malformed “Arca pexata.”
Reinhart (1943, p. 74) adopted the name Lunarca to in-
clude what had been included in the invalidly named
pelecypod Argina.
More study is needed to show the true affinities of the
genus. From the statistical study discussed earlier, 1t was
not clear as to where it should be placed. Heath (1941, p.
307) showed that anatomically it is distinctive in several
features from the Anadara group. Because of the flattened,
well-formed costae and distinct crenulations, it is tentatively
assigned to the Anadarinae. However, the low, opisthodetic
ligament suggests affinity to certain members of the Bar-
batia group in the Arcinae.
Type species.—Lunarca costata Gray, 1857; (of Argina)
Arca pexata Say (=A. ovalis Bruguiére) subsequent desig-
nation, Stoliczka, 1871.
Range.—Eocene-Recent.
Lunarca cf. L. ovalis (Bruguiére), 1789
Plate 2, figures 8a, 8b; Plate 6 figure 2
Arca ovalis Bruguiére, 1789, Encyclopédie Methodique, tome I, pt. 1,
fas UI)
A. campechiensis Gmelin, 1791, Systema Naturae, tome I, pars 6,
Vermes, p. 3312.
A. pexata Say, 1822, Acad. Nat. Sci. Philadelphia, Jour., vol. 2, pt.
p. 268. ;
Scapharca (Argina) campechensis (Dillwyn), Dall, 1898, Wagner
Free Inst. Sci., Trans., vol. 3, pt. 4, p. 650.
Lunarca ovalis (Bruguiére), Abbott, 1954, American Seashells, p. 345,
ple 27s) fag. te.
N
Diagnosis.—Shell subquadrate to subovate, left valve
larger than right, particularly in young individuals; liga-
mental area low, faintly striated vertically; hinge line
arched, teeth of posterior series variable; costae subequal in
width to interspace, faintly grooved ventrally gently
nodulose posteriorly and anteriorly, interspaces delicately
and abundantly lirate; ornament of two valves not notice-
ably discrepant; umbones prominent; umbonal ridge gently
rounded; beaks well anterior, prosogyre.
Discussion—Vhe valid name of this species may be
fixed by accurate determination of the dates of publication
of Bruguiére and Gmelin. The date 1792 appears on the
title page of Bruguiére’s Encyclopédie Méthodique. How-
ever, Sherborn and Woodward (1906, p. 579) ascertained
Bruguiére’s publication date of Tome I, Part 1 to be 1789.
AMERICANA (V, 34)
The first volume of the thirteenth edition of Systema
Naturae is in seven parts. Only the first part bears a date,
1788. Hopkinson (1907, p. 1035), who established the dates
for the other parts, stated that Part Six, the one here con-
sidered, was published in 1791.
Both Bruguiére and Gmelin referred to Lister’s figure
(1770, tab. 237, fig. 71). Because Lister did not use binom-
ial nomenclature and because Bruguiére’s publication date
preceded that of Gmelin, the citation of Bruguiére is the
correct one.
Specimens observed by me differ from Lister’s figured
specimen in that his form has a shorter posterio-dorsal mar-
gin; a wider umbonal area, less elongate, more ovoid form;
fewer, wider more nodose, ungrooved ribs; more arcuate
dental plate; and a lower ligamental area.
Dall (1898, p. 651) stated that left valves of specimens
which he referred to as Lunarca campechensis have narrow-
er flatter costae than the right valves and that the costae of
the left valves are often flattened and have grooved ribbing.
This difference in ornament was not observed in speci-
mens examined by me.
In the upper Tertiary, Lunarca cf. L. ovalis (Bru-
guiére) was collected from Longs, South Carolina. It was
also collected from the Pleistocene along the Intra-coastal
Canal at Core Creek Canal and from the Recent at Atlantic
Beach, North Carolina.
Hypotype.—U. N. C. Cat. No. 3531.
Range.—Pliocene-Recent.
Locality.—Longs, South Carolina.
Subfamily NOETIINAE Stewart, 1930
Diagnosis.—Equivalve, inequilateral; ligament amphi-
detic or prosodetic; ligamental area prominently striated
vertically, especially anteriorly; byssus absent; costae strong
with riblets in the interspaces; posterior muscle scar ele-
vated, anterior muscle scar commonly with thickened de-
posit of shell material; beaks orthogyre or opisthogyre,
inner margin crenulate.
Discussion.—Scapularca Cossmann, 1913 was treated by
him as a subgenus of Fossularca, which is a junior synonym
of Arcopsis von Koenen, 1885. Scapularca, judging by Mac-
Neil's (1938) hypotype of Scapularca scapulina Lamarck,
1805, the type species of the subgenus, is doubtfully an
Arcopsis. The ligamental area in this specimen is not in a
depressed, triangular area; the ribs are well formed, regu-
lar, and distinctly of two ranks; and crenulations are
prominent. MacNeil believed that certain species assigned
to Scapularca are progenitors of the Atlantic noetids.
Striarca Conrad, 1863 was placed in the Noetiinae by
Mip-ATLANTICG TERTIARY ARCACEA: Birp 33
MacNeil, but Striarca shows its affinities to Arcopsis in
having weak radial ribs of variable weight, both muscle
scars elevated, lack of crenulations on the inner margin, and
its overall shape. It is, however, large for an A rcopsis and
the ligamental area is not depressed as it is in Arcopsis. Be-
cause of its lack of crenulations and its relation to Arcopsis,
Striarca is placed in the Arcinae.
MacNeil stated that what he called Arginopsis sulla-
nensis, Which has previously been assigned to Lunarca, can
not be regarded as the ancestor of Lunarca because of the
well-developed vertical ligamental elements. Recent repre-
sentatives of Lunarca have vertical striae on the ligamental
area though this feature may not be so well developed as in
earlier species.
Arginella MacNeil, 1938 was separated from Arginop-
sis MacNeil, 1938 by MacNeil on what would appear to be
characters of specific rather than generic importance. The
distinction was that Arginella differs from the monotypic
Arginopsis in having less numerous ribs, less prosogyrate
and more central beaks, smaller size, shorter hinge line, and
ligamental area, and a more arcuate dental plate.
Both of these proposed genera have the shape, orna-
ment, opisthodetic liigamental area, and off-set dental series
of Lunarca, and are here considered synonymous with
Lunarca. MacNeil’s basis for placing earlier forms of
Lunarca in the Noetiinae is the well-formed vertical orna-
ment of the ligamental area. Assigning Lunarca to the
proper subfamily was shown previously to present a prob-
lem. The shape, opisthodetic location of the ligament, the
prosogyre beaks, and the off-set anterior series of teeth make
MacNeil’s proposed assignment of Lunarca appear arti-
ficial.
Range.—Eocene-Recent.
Genus NOETIA Gray, 1857
Subgenus NOETIA Gray, 1857
Diagnosis.—Shell subrhomboid to subtrigonal; liga-
ment amphidetic to prosodetic; costae never divided, sub-
equal throughout, ribs of interspaces (primary ribs) weak;
beaks nearly orthogyre to strongly opisthogyre; crenulations
deep, narrow; teeth tending to be cheyron-shaped, especial-
ly anteriorly, dental series arched.
Discussion.—MacNeil (1938) treated Pacific forms of
Noctia as a genus separate from the Atlantic forms. The
main reason for his distinction is his belief that the Atlantic
and Pacific groups were derived from completely distinct
ancestors. The ancestral stock for the Pacific group is taken
by MacNeil to be Protonoetia nigeriensis (Newton) , 1922,
from the west coast of Africa. The main basis for this pro-
posal seems to be that this species has interstitial ribs in
young individuals. A number of topotype specimens of the
species at the U. S. National Museum in the box with
MacNeil’s hypotopotype show vague interstitial ribs in
the umbonal ridge area. They are not the well-developed
interstitial ribs of Noetia. The ligamental area is narrow,
the posterior muscle scar is not elevated, and the beaks are
prosogyre. The ligamental area of the specimens studied by
MacNeil are vertically striated. As discussed previously,
weathered specimens of Anadara show this feature.
Though in general MacNeil’s topotypes are well preserved,
only slight corrosion brings about the striation of the liga-
mental area in some species of Anadara. Morphological-
ly what MacNeil has called Protonoetia is unlike Noetia,
and geographically is an Atlantic rather than a Pacific
form as noted by Reinhart (1943, p. 76).
The phyletic relations of the Noetiinae are uncertain.
The Pacific Coast and Atlantic Coast noetids are similar in
morphology and are here treated as belonging to the same
genus. However, Eontia MacNeil, 1938 seems distinct
enough to be treated as a subgenus of Noetia, and this
classification is followed here as in Reinhart (1943) .
Type species.—Arca reversa G. B. Sowerby, I, 1833
(=Noetia triangularis Gray, 1857), original designation.
Range.—Eocene-Recent.
Subgenus EONTIA MacNeil, 1938
Diagnosis.—Shell subrhomboidal to subtrigonal; liga-
ment amphidetic; beaks orthogyre to opisthogyre; costae of
some area of the shell always divided, larger medially than
elsewhere, primary ribs tend to be strongly developed;
crenulations relatively shallow and broad; teeth weakly
chevron-shaped, anterior extremes commonly L-shaped and
parallel hinge line, dental series long and straight or broad-
ly arched.
Discussion.—As between the two subgenera of Noetia
the ligament in Eontia is never prosodetic (in Noetia, 5.5.
it may or may not be prosodetic), the primary ribs are
often stronger, the costae are always bifid on some part of
the shell and irregular in weight around the shell, and the
crenulations are broader and not so deep as in Noetia, S.s.
MacNeil (1938) believed Scapularca interposita (De-
shayes) , 1860, from the Eocene of France, to be the ancestor
of Eontia. No Oligocene intermediate is known. Scapularca
scapulina (Lamarck) , 1805 was taken as progenitor of Shel-
3 PALAEONTOGRAPHICA AMERICANA
donella Maury, 1917, a genus® distinguished from Eontia by
MacNeil because of his belief that they came from different
FIGURE 2
Height-Length and Beak Position Changes in Noetia
(Eontia) spp.
100
90
80 7
fo}
5 oO
70 @ ° 3
a °6
l {
60
Ht/Lt 100 50
30
10 20 30 40 50 60 70 80 90 100 110 120
T»B/T,-Bx100
EXPLANATION OF FIGURE 2
Ht.=mean height of valve; Lt.=mean length of valve; Ts-B=
mean distance from anterior most tooth to beak; T.,-B—=mean distance
from posteriormost tooth to beak; 1 Noctia (Eontia) incile Yorktown
fm., Claremont, Virginia; 2 N. (E.) trigintinaria Duplin marl, Mag-
nolia, North Carolina; 3 N. (E.) carolinensis Yorktown fm., Black
Rock, North Carolina; 4 N. (E£.) limula Croatan sand, James City,
North Carolina; 5 N. (E.) platyura Waccamaw fm., Walkers Bluff,
North Carolina; 6 N. (E.) platyura Waccamaw fm., Town Creek,
North Carolina; 7 N. (E.) ponderosa Recent, Atlantic Beach, North
Carolina.
31f retained at all, Sheldonella should probably also be treated as
a subgenus of Noctia, as was done by Maury (1917).
(V, 34)
species of Scapularca. Derivation from different species
within the same genus is not a criterion for the recognition
of genera.
The following evolutionary trends are seen in species
of Noetia (Eontia) presented in this paper.
1. Number of costal grooves to increase from about one
to three on the umbonal ridge to simple or multiple grooy-
ing of all ribs. This trend reaches its fullest attainment in
Noetia (Eontia) carolinensis from the upper Yorktown for-
mation and regresses in stratigraphically younger forms.
2. Beaks tend to migrate posteriorly in relation to the
hinge line and to become more opisthogyre. In this trend,
indicated in Figure 2 by Ts-B/T,-B, N. (E.) carolinensis,
a Miocene species, displays a stage intermediate between
Pliocene and Recent species. The beaks are nearly orthogyre
in N. (£.) carolinensis so the ratio T,-B/T,-B is relatively
greater still than in the Pliocene species. N. (£.) limula and
N. (E.) platyura of the Pliocene have the beaks more an-
terior in relation to the dental series and have slightly
opisthogyre beaks. N. (E.) ponderosa has the beaks situated
posteriorly and the beaks are opisthogyre with the result
that the ratio T,-B/T,-B is distinctive for that species.
The position of the beaks with respect to the Ht./Lt.
ratio of the valves shows a similar trend. In the elongate
N. (E.) incile the beaks are subterminal but are posterior
to this position in the less elongate N. (E.) trigintinaria.
The beaks are subcentral in N. (E.) carolinensis (Miocene)
and N. (£.) ponderosa (Recent) which tend to be sub-
quadrate in outline. The beaks of N. (£.) limula are more
anterior and the valves are more elongate than in N. (E.)
platyura (both are Pliocene species) .
3. Height of valves to increase in relation to length of
shell. Figure 2 shows the trend. N. (E.) limula, an excep-
tion to the rule, is seen to have the ratio Ht./Lt. similar to
that of N. (£.) incile from the Yorktown formation.
Type species.—Arca ponderosa Say, 1822, original designa-
tion.
Range.—Miocene-Recent.
Noetia (Eontia) incile (Say), 1824
Plate 2, figures 10a, 10b, 11
Arca incile Say, 1824, Acad. Nat. Sci. Philadelphia, Jour., vol. 4, pt.
Lips 139 pleats tiga 3:
Noetia incile (Say), Dall, 1898, Wagner Free Inst. Sci., Trans., vol.
3, pt. 4, p. 632.
Eontia incile (Say), MacNeil, 1938, U. S.
189-A, p. 13, pl. 1, figs. 25-28, 30, 31.
E. incile suffolkensis MacNeil, ibid., p. 16, pl. 1, fig. 29.
E. incile mansfieldi MacNeil, tbid., p. 15, pl. 1, figs. 23, 24.
Geol. Sur., Prof. Paper
Diagnosis.—Shell subrhomboid, tending to be alate, with
Mip-ATLANTIC ‘TERTIARY ARCACEA: Birp 3!
umbonal ridge distinct; ligamental area narrow in relation
to length of ligamental area but hinge area broad; teeth in
long continuous series, some in posterior series cheyvron-
shaped, two or three anterior ones parallel the hinge line:
hinge long, straight; costae coarse, only the one or two ribs
of the umbonal ridge are grooved, grooves feeble, single.
ventral only; beaks orthogyre, subterminal.
Discussion.—The subspecies described by MacNeil (1938)
do not seem to be necessary. ‘They were based on geographic
distribution and small differences in form. Representative
specimens of the type figured by him to characterize the
subspecies can all be found at one locality and grade in-
sensibly into each other. Several forms with a tendency for
strong alation were found with the more normal forms. One
specimen was as strongly winged as the figured specimen of
E. incile mansfieldi a “variety” supposedly limited to Flor-
ida faunas.
From Table 10 it can be seen that this species is distinct
from all others to which it was compared. It is found in the
Miocene from Maryland to Florida.
Hypotypes.—U. N. C. Cat. Nos. 3532, 3533.
Range.—Choptank-Yorktown Miocene.
Localities.—Nos. 18-22.
Noetia (Eontia) trigintinaria (Conrad), 1863
Plate 2, figures 12a, 12b, 13
Anomalocardia trigintinaria Conrad, 1863, Acad. Nat. Sci. Philadel-
phia, Proc., vol. 14, p. 289.
Noetia protexta Conrad, 1875, Kerr’s Geol. Report of North Carolina,
Appendix A, p. 19, pl. 3, fig. 5.
Eontia trigintinaria (Conrad), MacNeil, 1938, U. S. Geol. Sur., Prof.
Paper 189-A, p. 16, pl. 1.
Diagnosis.—Shell rhomboid, posterior margin nearly
straight or emarginated, with distinct umbonal ridge; liga-
mental area narrow in relation to length of ligamental area;
posterior series of teeth with few chevron-shaped members
(often none) , anterior series rarely with members parallel
to hinge; hinge line long, straight; costae coarse, feebly and
singly divided; beaks slightly opisthogyre, situated above
the anterior one-third of the hinge.
Discussion.—This species is closely related to Noetia
(Eontia) incile but may be distinguished from it by its less
anteriorly situated beaks (which are slightly opisthogyre) ,
slightly more delicate, more lirate ribs, and its more regular
anterior teeth which do not tend to parallel the hinge line.
The combination y=T.-B, x=T,-B was compared statisti-
cally for the two species. A significant difference between N.
incile and N. trigintinaria was noted at the 5% level of sig-
nificance (two-sided) which supports the treatment of the
S
or
two as separate species. Also the slope for y—HPM, x—Lt.
was significantly different at this level of probability.
From Dall’s original specimen of Noetia limula “var’
filosa, MacNeil selected a neotype of Eontia trigintinaria
“var.” filosa (Conrad). The “variety”, in which the costae
are divided only near the umbonal ridge unlike the
abundant division of costae in N. (E.) limula, was not
collected by me. However, some of the specimens of N.
(E.) carolinensis have a similar shape, but the costae are
divided anteriorly and posteriorly in N. (E.) carolinensis,
while the ribs of N. (E.) trigintinaria “var.” filosa are di-
vided only posteriorly.
Noetia (Eontia) trigintinaria ranges from North Caro-
lina to Florida but was only observed from Natural Well in
this study.
Hy potypes.—U. N. C. Cat. Nos. 3534, 3535.
Range.—Yorktown-Duplin Miocene.
Locality.—No. 6, Natural Well, N. C.
Noetia (Eontia) carolinensis Conrad, 1863
Plate 3, figures 6a, 6b
Noetia ponderosa var. carolinensis Conrad, 1863, Acad. Nat. Sci.
Philadelphia, Proc., vol. 14, p. 280.
Arca carolinensis (Conrad), Heilprin, 1881, Acad. Nat. Sci. Philadel-
phia, Proc., vol. 33, p. 450.
Eontia carolinensis (Conrad), MacNeil, 1938, U. S. Geol. Sur., Prof.
Paper 189-A, p. 17, pl. 2, figs. 5, 6.
Diagnosis.—Shell subrhomboid to subquadrate, umbonal
ridge rounded, indistinct, some forms with ventral sag;
ligamental area narrow in relation to length of ligamental
area; anterior and posterior series of teeth subequal in
length, outer members of posterior series chevron-shaped,
tending to be displaced ventrally at the posterior extremity,
anteriormost teeth may parallel hinge line or are at a low
oblique angle; costae singly divided more or less across en-
tire shell, division posteriorly extending farther dorsally
than in anterior costae, interspaces and costae both lirate,
liration better preserved in interspaces; hinge long; beaks
slightly opisthogyre, subcentrally located.
Discussion.—This form attains a larger size than the two
preceding species. Noetia (Eontia) carolinensis shows its
relation to its close relative, N. (£.) trigintinaria in having
two of the three regression coefficients of ‘Table 10 in com-
mon within limits of 10°% significance level with that
species, in having a strongly lirate shell, and in having the
end members of the anterior dental series at an angle to the
hinge rather than parallel to the hinge. The combination of
characters for which the regression coefficients are statistic-
ally distinct (y=T.-B, x=T,-B) is an index to the position
36 PALAEONTOGRAPHICA
of the beak with respect to the dental series. In this com-
bination, as well as in general morphology, N. (E.) trigin-
tinaria is intermediate between N. (E.) incile and N. (E.)
carolinensis.
(Eontia)
along the Chowan River.
Hypotype.—U. N. C. Cat. No. 3536.
Range.—Yorktown Miocene.
Localities.—Nos. 12, 13, and 14.
Noetia carolinensis has been observed only
Noetia (Eontia) limula (Conrad), 1832
Plate 3, figures la, 1b, lc
Arca limula Conrad, 1832, Fossils of the Tertiary formations, p. 15,
pl. 1, fig. 1; Reprint, 18
A. limula Conrad, Conrad, 1845, Fossils of the Medial Tertiary of the
United States, p. 57, pl. 30, figs. 2. Reprint :
Arca (Noetia) limula Conrad, Dall, 1898, Wagner Free Inst. Sci.,
Trans., vol. 3, pt. 4, p. 631.
Eontia limula (Conrad), MacNeil, 1938, U. S. Geol. Sur., Prof. Paper
189-A, p. 19, pl. 2, fig. 9.
Diagnosis.—Shell subrhomboid, elongate, expanded pos-
teriorly, with rounded umbonal ridge, marked ventral sag;
ligamental area wide with respect to length of ligamental
area; posterior series of teeth longer than anterior, grad-
ually curved outward dorsally, anteriormost teeth bend ven-
trally, upper portion of L-shaped members usually parallel
hinge; hinge shortened; ventral margin at distinct angle to
hinge; costae divided by one, or more rarely, two grooves,
more or less across entire shell, interspaces and costae lirate;
beaks opisthogyre, subcentral in relation to dental series,
anterior in relation to length of shell.
Discussion.—TVhis species is not statistically distinct from
Noetia (Eontia) carolinensis on the basis of the characters
used in the statistical analysis (Table 10). N. (E.) limula
may be distinguished by its more anteriorly located beaks
(in relation to the length of the valve) , posterior expansion
of shell, more elongate form, slightly more opisthogyre
beaks, and more constant ventral sag (which is only rarely
present in N. (E.) carolinensis) .
Noetia (Eontia) limula is a common species at the Croa-
tan outcrop at James City, North Carolina, locality; it is
rare in the Waccamaw. The Foraminifera at the James City
locality indicate shallower water than do the Foraminifera
at the Town Creek locality (see Table 5), the station at
which N. (E.) platyura is most common. These data sug-
gest that N. (E£.) limula inhabited shallower water than the
contemporaneous N. (E.) platyura, although a few repre-
sentatives of N. (E.) limula were found at the Town Creek
locality.
Hypotype.—U. N. CG. Cat. No. 3537.
AMERICANA
Range.—Pliocene.
Localities.—Nos. 1, 7, and 8.
Noetia (Eontia) platyura (Dall), 1898
Plate 3, figures 4, 5, 7a, 7b
Arca limula var. platyura Dall, 1898, Wagner Free Inst. Sci., Trans.,
vol. 3, pt. 4, p. 632.
Eontia lumberensis MacNeil, 1938, U. S. Geol. Sur., Prof. Paper 189-
ANG Sos MEL FOL ZA satecy Wh EF
. tillensis MacNeil, 1938, ibid., p. 20, pl. 2, fig. 10.
. variabilis MacNeil, 1938, ibid., p. 20, pl. 2, fig. 12-16.
. variabilis quadrata MacNeil, 1938, ibid., p. 21, pl. 2, fig. 11.
. platyura (Dall), MacNeil, 1938, ibid., p. 22, pl. 3, figs. 1-3.
. variabilis clewistonensis MacNeil, 1938, ibid., p. 22, pl. 3, fig. 5.
soso Es Rt >is]
Diagnosis.—Shell elongate, subrhomboid to subquadrate,
umbonal ridge rounded, without ventral sag, or with sag
poorly and indefinitely developed; ligamental area wide in
relation to length of ligamental area; posterior row of teeth
slightly longer than anterior row, extreme anterior teeth
L-shaped and parallel to hinge; hinge short, in some speci-
mens parallel to ventral margin; costae usually divided
more or less across entire shell, grooves single or double,
interspaces and costae. lirate; beaks opisthogyre, anterior in
relation to the length of the shell.
Discussion.—Judging from the types of Noetia (Eontia)
platyura and N. (E.) variabilis, no method of distinction of
the two exists. MacNeil (pp. 22-23) stated the N. (3)
platyura may be distinguished from N. (E.) variabils in
having the anterio-dorsal margin more angulated, the bor-
der more horizontal, and the posterior margin more vertical.
‘These differences are not constant nor are the minor differ-
ences in form notable at a particular geographical location
nor a particular horizon. Both types are present at the
‘Town Creek locality where intergradation of the two forms
can be seen. At this locality, forms referable to the other
specific names included in the synonymy are also present.
Here gerontic individuals show the inflation which Mac-
Neil used to characterize N. (E.) tillensis. The short, high
form referred to by MacNeil as E. variabilis quadrata was
collected at the type locality, Walkers Bluff, North Caro-
lina, and also at Town Creek. FE. variabilis clewistonensis
is in no way distinctive. The “rotund outline, inflated disk,
and rounded posterio-ventral margin” used as diagnostic
features of the “variety” by MacNeil are not particularly
evident in his figure (pl. 3, fig. 5); though the “variety”
was supposedly restricted to Florida faunas, similar forms
occur at Town Creek.
The individuals in the sample of N. (E.) platyura from
‘Town Creek show much variation but complete intergrada-
tion. Gerontic forms show highly inflated umbonal ridges
and high ligamental areas. Some individuals at other onto-
genetic stages have the ventral margin subparallel to the
Mip-ATLANTIC TERTIARY ARGAGEA: Birp 5
hinge and in others not. Specimens may be found with the
dorsal and posterior and anterior margins meeting at nearly
right angles, in others the angles are obtuse. Nearly all
forms are high in relation to length, thick shelled, have all
or most of the costae divided once or, in the area of the
rounded umbonal ridge, twice (in young forms only the
costae on and near the umbonal slope are divided), and
lack the ventral sag.
Eontia lumberensis was used by MacNeil for the speci-
mens from Lumberton, North Carolina. He noted that
these specimens were like E. variabilis but erected a new
species because of his belief that the latter species were
restricted to the Pliocene. Stratigraphic occurrence alone is
not a valid basis for distinguishing species and E. lwmberen-
sis is included in the synonymy of N. (E£.) platyira because
it is in no way distinguishable from N. platyura.
Noetia (Eontia) platyura differs from N. (£.) limula in
that N. (£.) platyura tends to be: (a) more sharply trun-
cated posteriorly and typically lacks the posterior flare, (b)
slightly higher in relation to length (see Text fig. 2), (c)
thicker shelled, and (d) devoid of the ventral sag. N. (E.)
carolinensis is separable from N. (£.) playtura in having
the beaks more centrally located, a longer hinge line, the
posterior margin more broadly rounded, and the ribs
slightly more elevated.
From Table 10 the general lack of statistically significant
differences in the characters used for the closely related
species N. (E.) carolinensis, N. (E.) limula, and N. (E.)
platywra can be seen. These species are distinguished here
by qualitative characters.
Hypotypes—U. N. C. Cat. Nos. 3538-3540.
Range.—Duplin Miocene—Waccamaw Pliocene.
Localities.—Nos. 1, 2, 4, and 5.
Noetia (Eontia) ponderosa (Say), 1822
Plate 3, figures 3a, 3b; Plate 6, figure 6
Arca ponderosa Say, 1822, Acad. Nat. Sci. Philadelphia, Jour., Ist ser.
vol. 2, p. 267. :
Arca (Noetia) ponderosa Say, Dall, 1898, Wagner Free Inst. Sci.,
Sirans:. voles, pt. 45 p. 633.
Eontia ponderosa (Say), MacNeil, 1938, U. S. Geol. Sur., Prof. Paper
189-A, p. 24, pl. 3, figs. 9-12.
Diagnosis.—Shell subquadrate to subtrigonal, with sharp-
ly truncated, oblique posterior margin, never with ventral
sag; umbos prominent, high, umbonal ridge sharply round-
ed; ligamental area wide in relation to length of ligamental
area; posterior series of teeth usually without chevron-
shaped members, tending to be in a shorter row than an-
terior series, extreme members of anterior dental series L-
shaped; costae tending to be flattened, few to many costae
with single grooves, costae and interspaces with lirations,
xi
better preserved in interspaces, primary ribs feeble; hinge
short, subparallel to ventral margin; beaks strongly opis-
thogyre, subcentral in relation to length of shell, posterior
with respect to T.-B/T,-B.
Discussion.—Vhe most distinctive features of this species
are its tendency for a subtrigonal shape, short hinge and
subcentral beaks, sharply rounded umbonal ridge, and short
dental series (which is distinctive in that the anterior series
is Jonger than the posterior series). Table 10 (See also Text
fig. 2) reflects this trait by the fact that the slope y=T.-B,
x—T,-B for this species is significantly steeper than that
for all other species included in the table.
Figure 2 shows the trend through time for the species
studied to develop a short high form and to shift the beaks
posteriorly.
The amount of division of costae in the adult of Noetia
(Eontia) ponderosa is variable. In a few individuals, nearly
all of the costae are singly or, near umbonal slope, multiply
divided; more commonly the costae are grooved only in the
area of the umbonal ridge. N. (E.) playtura, a close ancestor
of N. (£.) ponderosa, shows this same variation 1n orna-
mentation, but typically has the costae divided farther an-
teriorly than in N. (£.) ponderosa and in some forms has
the costae near the umbonal ridge divided more than twice.
Noetia (Eontia) ponderosa may readily be distinguished
from N. (E£.) platyura by its more quadrate or trigonal
form, more central beaks (in relation to length of valves) ,
longer anterior dental series (as indicated by T.-B/T,-B) ,
higher umbones, and more flattened ribs.
A few forms similar to Noetia (Eontia) palmerae Mac-
Neil, 1938, which he believed to be Pleistocene only, were
collected with N. (E.) ponderosa from Atlantic Beach,
North Carolina. The preservation of these individuals, as
well as their occurrence, the Outer Banks, indicates that
they are probably Recent forms. These specimens show the
same variation in division of costae as N. (£.) ponderosa.
The other features used by MacNeil to differentiate N.
(E.) palmerae from N. (E.) ponderosa, less carinate um-
bonal ridge and less flat-topped costae, do not serve to dis-
tinguish Recent specimens separable by shape.
MacNeil did not illustrate the interior of his species but
stated that the beaks are just posterior to the center (prob-
ably to the hinge not to the shell). MacNeil’s holotype and
a paratype bear this out. In Recent specimens similar to
Noetia (Eontia) palmerae the ratio of T.-B/T,-B is about
equal to one which is slightly less than N. (E.) ponderosa
Based on the observations above it seems likely that N.
(E.) palmerae deserves no more than subspecific rank and
may prove to be conspecific with N. (E.) ponderosa. The
38 PALAEONTOGRAPHICA AMERICANA (V, 34)
thin-shelled Pleistocene forms from Maryland and New
Jersey are probably ecophenotypic.
Noetia (Eontia) ponderosa is common to abundant along
the beaches of the Atlantic Ocean from Virginia to Florida
and in the Gulf of Mexico.
Hypotype.—U. N. C. Cat. No. 3541.
Range.—Pleistocene-Recent
Locality.—Atlantic Beach, N. C.
TABLE 10
Comparisons of Regression Coefficients in Noctia*
] 9 3 4 5 6 7
AGB GeeAGB Gy AB IG ACB Gs VACEG) “AUB IG ACBIG
a=
Sa = — 9010/0
eee OnOn0
=a nOROKO ORO10 0) 0).0
6 dha Oe ee 0n0=
i 0= OO
Symbols: A.y = HPM, x = Lt.; B.y = WI]; x = LI; C. y=
eB siy,-B:
Abbreviations:
HPM — Height of posterior muscle scar.
Others—See Glycymeris (Table 11)
Significance level = 10%, 2 sided.
Equations:
Sample no.
| A. y = 0.284 x—0.225 Noetia (Eontia) incile,
B. y = 0.179 x + 0.062 Yorktown formation,
C.y = 0.243 x +. 0.198 Kings Mill Wharf, Va.
2 A.y=0.185x-+ 0.073 N. (E£.)
B. y = 0.225 x—0.129 Yorktown formation,
C. y — 0.756 x + 0.266 Black Rock, N.C.
carolinensis,
3 A.y=0.165x+ 0.124 N. (E.) platywra, Wac-
B. y — 0.266 x —0.100 camaw formation, Walk-
Cc. y — 0.651 x + 0.243 ers Bluff, N.C.
| A.y=0.178 x +.0.070 N. (E.) platyura, Wac-
B. y — 0.328 x — 0.348 camaw formation, Town
C. y = 0.556 x + 0.650 Creek, N.C.
5 A.y=0.175 x—0.051 WN. (E.) limula, Croatan
B. y = 0.252 x—0.147 sand, James City, N.C.
C. y = 0.644 x + 0.278
6 A.y=0.195 x—0.010 N. (E.) ponderosa, Re-
B. y = 0.254 x—0.057 cent, Atlantic Beach,
la
C
Me
y—1.192 x—0.072 N.C.
~I
>
y=0.155x+0.061 N. (E.) trigintinaria,
B. y = 0.201 x +. 0.005 Duplin’ marl, Natural
y= 0.418 x +.0.077 Well, N.C.
*Table notation as in Glycymeris analysis (Table 11).
Family GLYCYMERIDAE Stewart, 1930
Genus GLYCYMERIS da Costa, 1778
Synonyms.—See Nicol, 1945.
Diagnosis—Equivalve, slightly inequilateral; ligament
amphidetic, duplivincular; ligamental area with strong to
weak chevron markings, faint longitudinal lines, and, in
weathered specimens, with vertical ornament; costae usually
well developed, rarely absent, striae present on costae or
not; posterior muscle scar elevated; inner margin crenu-
lated in intercoastal areas; beak orthogyre to slightly opis-
thogyre; teeth commonly chevron-shaped, ventralmost mem-
bers subparallel to hinge, short central teeth commonly
lost in ontogentically advanced individuals.
Discussion.—The family has been intensively studied by
Nicol (1945, 1950). In the 1950 paper, Nicol postulated
that the group evolved from a cucullaeid stock during late
Jurassic. This hypothesis, which seems to be good, is based
on similarity in ornamentation, shape, ligamental area,
muscle scars, and development of teeth in the two groups.
A diagnosis of the family and a list of genera and sub-
genera proposed by various authors is given by Nicol
(1945). In the paper, Nicol gave the type species for the
subgenera and genera which are valid according to the rules
of binomial nomenclature but which may or may not prove
to be distinct with additional study. Subgenera are not
treated in the present paper.
Type species.—Arca glycymeris Linné, 1758, original
designation.
Range.—Cretaceous-Recent.
Glycymeris anteparilis Kellum, 1926
Plate 5, figures la, 1b, 2
Glycymeris anteparilis Kellum, 1926, U. S. Geol. Sur., Prof. Paper 143,
p. 35, pl. 8, figs. 4-6.
Diagnosis.—Shell nearly symmetrical, thick, highly con-
vex; ligamental area marked with strongly chevron-shaped
erooves; external ornament consists of fine striations and
dark, minutely raised radial lines which on weathering be-
come grooves; dental series broadly rounded, lateral teeth
parallel to hinge, larger than central teeth which are per-
Mip-ATLANTIC TERTIARY ARGCACEA: BIRD 59
pendicular to hinge; hinge line long, straight; crenulations
small, numerous, in position of dark radial lines which
separate areas of fine striations; beaks prominent, ortho-
gyre.
Discussion.—Restricted to beds at Silverdale, North Caro-
lina, which most recent workers refer to the lower Miocene
(see section on stratigraphy) .
The results of a statistical study of this and other species
of Glycymeris are presented in Table 11. In this table all
possible combinations are not presented; only combina-
tions of species which appear to be closely related in quali-
tative characters are compared, On the basis of the char-
acters selected for statistical study (selected by graphical
comparisons of regression lines from many combinations of
characters) , Glycymeris anteparilis and Glycymeris parilis
can not be distinguished. Qualitatively, the external orna-
ment is similar in the two species. No specimen of G. parilis
was observed which was not weathered, and only one speci-
men of G. anteparilis was found which showed little effects
of weathering. Both species have external ornament of
broad, finely striated zones separated by narrow grooves.
The ornament of one relatively unweathered specimen of
Glycymeris anteparilis showed areas of fine striations sep-
arated by darkened, slightly raised, radial lines. The crenu-
lations of the inner margin of the valves are directly unde1
the darkened lines indicating that these lines are not true
ribs. In weathered specimens, the position of the darkened,
raised lines is occupied by the grooves which separate the
areas of fine striations. The areas between the grooves be-
come gently rounded with more weathering and look like
more typical ribs. The ornament of G. parilis is similar to
that of G. anteparilis. The nature of the ornament in un-
weathered or slightly weathered forms is not known for
G. parilis.
Glycymeris anteparilis is easily distinguished from G.
parilis by having more prominent umbos and beaks, well-
defined chevron ornament on the ligamental area, a nearly
orbicular shell, and teeth present in the center of young and
adult specimens.
Hypotypes.—U. N. C. Cat. Nos. 3542, 3543.
Range.—Lower Miocene at Silverdale, N. C.
Locality.—Silverdale, North Carolina.
Glycymeris parilis (Conrad), 1843
Plate 4, figures 2a, 2b, 4a, 4b
Pectunculus parilis Conrad, 1843, Acad. Nat. Sci. Philadelphia, Proc.,
vol. 1, p. 306.—1845; Fossils of the Medial Tertiary of the United
States, p. 64, pl. 36, fig. 2.
Glycymeris parilis (Conrad), Dall, 1898, Wagner Free Inst. Sci.,
Trans., vol. 3, pt. +, p. 609; Glenn, 1904, Geol. Sur. Maryland,
Miocene, p. 393, pl. 108, figs. 1, 2.
Diagnosis—Shell high in relation to length, obliquely
truncated posterio-dorsally, strongly convex as adult; liga-
ment with faint chevron markings; costae coarse, not prom-
inent, with faint suggestions of fine striations, interspaces
narrow; teeth tending to be large, absent in center of hinge
line, centralmost members chevron-shaped, more lateral
ones subparallel to hinge; crenulations numerous; beaks
orthogyre.
Discussion.—Young individuals of Glycymeris parilis have
nearly straight anterior, posterior, and dorsal margins and
the ventral margin broadly rounded, costae of uniform
weight, the center of the hinge edentulous, and low con-
vexity of the valves. In young specimens of G. anteparilis
the posterior and anterior margins are rounded, teeth are
present in the center of the hinge, the ligamental area is
high, and the convexity is high. Also the ligamental area
shows distinct chevron grooves and the beaks are prom-
inent unlike G. parilis.
The young of Glycymeris americana may be distinguished
from either G. anteparilis or G. parilis by the nature of the
ornament, which in G. americana consists of broad finely
striated ribs of variable weight. The interspaces are narrow
as in G. anteparilis and G. parilis. Also the convexity is low
unlike G. anteparilis and the anterior and posterior margins
are rounded unlike G. parilis. The ligamental area of the
young of G. americana is low.
Glycymeris lentiformis is best distinguished from G.
parilis by its large widely spaced teeth. No juvenile of G.
lentiformis. was found.
The ornament of Glycymeris parilis serves to distinguish
it from all other species except G. anteparilis which is dis-
cussed above. (See comments on possible similarity to orna-
ment of G. anteparilis in unweathered specimens under the
discussion of G. anteparilis.) G. americana and G,. lentifor-
mis have costae with relief and well-formed striations. How-
ever, unweathered specimens of G. parilis, if ever found,
may show ornamentation similar to G. americana and G.
lentiformis. Adults of G. parilis are similar to those of G.
lentiformis if the external ornament, which though useful
for distinguishing the two may be a preservation phenom-
enon in G. parilis, is not considered. ‘The other distinguish-
ing characters are that G. parilis has slightly less prominent
beaks, a higher shell in relation to length, an obliquely
truncated posterio-dorsal margin, and teeth smaller in re-
lation to size than G. lentiformis.
Again ignoring external ornament as a criterion for dis-
tinction, Glycymeris americana is less convex in relation to
length, has a narrower ligamental area in relation to length
of ligamental area (Table 11, samples 6 and 14), is not so
10 PALAEONTOGRAPHICA AMERICANA (V, 31)
high in relation to length, and has relatively smaller teeth
than G. parilis.
Hypotypes.—U. N. C. Cat. Nos. 3544, 3545.
Range.—Calvert Miocene.
Locality.—Plum Point, Maryland.
Glycymeris lentiformis (Conrad), 1835
Plate 5, figures 4a, 4b
Pectunculus lentiformis Conrad, 1835, Fossil shells of the Tertiary
Formations of North America, Repub. vol. 1, No. 3, P- 36; Con-
rad, 1845, Fossils of the Medial Tertiary of the United States,
p. 64, pl. 36, fig. 1. ,
Glycymeris americana (Defrance), Dall, 1898, Wagner Free Inst. Sci.,
Trans., vol. 3, pt. 4, p. 609 in part.
Diagnosis.—Shell suborbicular, anterior margin tending
to be straight, posterior margin broadly rounded; liga-
mental area moderately broad in relation to length, chevron
markings poorly developed; costae numerous, with fine
striae, interspaces narrow; teeth tending to be large, widely
spaced, especially in adults, absent in center of older indi-
viduals, central members chevron-shaped, lateral ones tend-
ing to parallel hinge, dental series broadly arched; crenula-
tions small, numerous; beaks moderate in size.
Discussion.—Dall (1898, pp. 609, 611) considered this
form a senile G. americana. However, the characters which
separate the two are observable in the neanic (no young
forms were found) as well as adults. The most obvious dif-
ference is in the teeth; in G. lentiformis they are much
larger and more widely spaced. The regression coefficients
for the two species are all distinct (Table 11, samples 6 and
13). Hence G. lentiformis is restored as a species.
No significant differences in the regression coefficients of
Glycymeris lentiformis and G. parilis were noted. G. lenti-
formis may be an intermediate form in the evolution of G.
parilis to G. americana. The series is a broken one, however,
for with the exception of G. swbovata which is rare in the
Choptank formation, no undisputed occurrence of Glycy-
meris from the Choptank or St. Marys formations is known.
The teeth of G. parilis are slightly smaller than those of G.
lentiformis and those of G. americana much smaller.
Glycymeris lentiformis is a rare species. Only two speci-
mens of it were collected outside the Boykins, Virginia,
locality where many specimens were present.
Hypotype.—U. N. C. Cat. No. 3546.
Range.—Yorktown Miocene.
Localities.—Nos. 17, 21, and 22.
Glycymeris americana (Defrance), 1826
Plate 4, figures la, 1b; Plate 5, figures 3a, 3b, 6a, 6b
Pectunculus americanus Defrance, 1826, Dictionnaire des sciences
naturelles, vol. 39, p. 225.
P. quinquerugatus Conrad, 1845, Fossil shells of the Medial Tertiary
of the United States, p. 63, pl. 34, fig. 3.
P. tricenarius Conrad, 1845, ibid., p. 63, pl. 35, fig. 1.
Glycymeris americana (Defrance), Dall, 1898, Wagner Free Inst.
Sci., Trans., vol. 3, pt. 4, p. 609 in part; Gardner, 1943; U. S.
Geol. Sur., Prof. Paper 199-A, p. 27, pl. 1, figs. 16-21.
Diagnosis.—Shell outline nearly circular to subovate; liga-
mental area with weak chevron grooves; external ornament
of numerous rounded costae with many fine striae, and nar-
row interspaces, which are also finely striated; teeth in a
curved series, edentulous in center of adult individuals,
some members chevron-shaped, tend to be located near
center of dental series, posterior series sometimes elongated;
hinge line variable in length; crenulations numerous; beaks
nearly orthogyre.
Discussion.—The distribution of this species in the East
Coast Miocene is erratic. Along the James River in Virginia,
only two individuals were found. Near Suffolk, Virginia, it
is about as common as Glycymeris subovata, but neither
species is abundant there. It was not observed at other lo-
calities in southern Virginia. G. americana is common at
Mt. Gould, North Carolina, but at Colerain, nearby to the
north, it is absent. It is present to the south at Williamston
and was not observed at other localities (see index map)
south to Natural Well, North Carolina, where the species
is common. It is absent in the Duplin marl at Lumberton,
North Carolina.
Glycymeris americana is present in every locality visited
in the Waccamaw formation, though it 1s not common at
Walkers Bluff and is absent in the one Croatan locality
visited (James City). Differences in the paleoecology from
locality to locality apparently determined the distribution
of G. americana; relative age does not account for the dis-
tribution (see comments on stratigraphy) .
Glycymeris americana is variable in the Waccamaw for-
mation, where it is most abundant. So much variation exists
that statistically distinct subsets can be separated visually.
The intergradation of the subsets is complete. One subset
(Pl. 4, figs. la, 1b) is characterized by forms having a sub-
circular outline, a straight, long dorsal margin, wide hinge,
and subequal anterior and posterior series of teeth. ‘The
dental series forms a broad, curved arch. In the other subset
(PI. 5, fig. 3) the species is subovate in shape and is pro-
duced posteriorly, the dorsal margin is sharply rounded,
the hinge line is short, the posterior series of teeth is
elongate, and the anterior and posterior series of teeth meet
at a more acute angle than the symmetrical subset (speci-
men PI. 5, fig. 3b is atypical in this last respect) . So strik-
ing is the similarity of the second subset to G. subovata
that it appears as if G. swbovata with reduced chevron
grooving on the ligamental area has interbred with G.
americana, Glycymeris subovata which is reported only
Mip-ATLANTIG TERTIARY ARGACEA: BirpD LI
from the Miocene is not present in the Pliocene Wacca-
maw formation.
It can be seen from Table 11 that the sample of G.
americana trom Natural Well (samples 6) is statistically
more distinguishable from the morphologically asymmetri-
cal subset from Acme, North Carolina, (sample 8) than
sample 6 is distinguishable from the G. swbovata sample
from Lumberton, North Carolina, (sample 7). The mor-
phologically symmetrical subset from Acme (sample 9) 1s
more like G. americana from Natural Well than is sample
8. G. subovata never has fine striations on costae as does
G. americana and the two species can not be confused.
These studies show: (a) the similarity of the asymmetri-
cal Glycymeris americana and G. subovata; (b) the fact of
statistical differences in the two subsets of G. americana;
(c) the change in G. americana from the Duplin of Natural
Well to the Waccamaw of Acme.
Lists of synonyms of Glycymeris americana have been
prepared by Dall (1898, p. 609) and Nicol (1953, p. 451),
whose list is shorter; these lists are readily available and
are not repeated here. Nicol (1953) studied the peculiar
form of G. americana (which is characterized by wrinkles
along the dorsal margin of the shell, especially the posterior
side of the umbo) from Natural Well and termed this
form the “mutant rugosa.” Conrad (1841, p. 346) seems to
have been the first to have noticed this form and he gave
it the rank of species, calling it Pectunculus quinqueru-
gatus. Dall (1898, p. 611) thought the wrinkled form repre-
sented parasitization, but, as noted by Nicol, the shell shape,
size, and thickness is otherwise as in typical individuals of
G. americana. Nicol observed this variant in the upper Mio-
cene of North Carolina, South Carolina, and Georgia. He
found a distinct species (G. aberrans) displaying the same
phenomenon in the upper Miocene of Florida. Nicol postu-
lated that G. aberrans, which also has been reported from
South Carolina, was derived from the mutant form of G.
americana.
Glycymeris americana is rare in the Recent; it is found at
moderate depths from North Carolina to northern Florida
and west to Texas (Abbott, 1954, p. 349).
Ay potypes.—U. N. C. Cat. Nos. 3547-3549.
Range.—Yorktown Miocene-Recent.
Localities.—Nos. 1, 2, 3, 4, 6, 11, and 13.
Glycymeris subovata (Say), 1824
Plate 4, figures 3a, 3b; Plate 5, figures 5a, 5b, 9, 10a, 10b
Pectunculus subovatus Say, 1824, Acad. Nat. Sci. Philadelphia, Jour.,
Ist series, vol. 4, p. 140, pl. 10, fig. 4.
Axinaea (Pectunculus) subovata Say, Conrad, 1863, Acad. Nat. Sci.
Philadelphia, Proc., p. 581.
Glycymeris subovata (Say) Dall, 1898, Wagner Free Inst. Sci., ‘Trans.,
vol. 3, pt. 4, p. 611.
G. subovata var. plagia Dall, 1898, ibid., p. 611, 612.
G. drymanos Gardner, 1926, U. S. Geol. Sur., Prof. Paper 142-A, p. 36,
Ploeg seedias
G. waltonensis Gardner, 1926, ibid., Da Si/n pla Op bigs sibs
Diagnosis.—Shell nearly symmetrical, with round dorsal
margin; ligamental area with more or less distinct chevron
grooving; costae coarse, fine striations absent, some indi-
viduals showing tendency to develop weak secondary ribs
on costae, costae usually round but in some individuals
sharply crested and in others nearly flat; teeth in center
becoming resorbed in older individuals, subequal in size
throughout, tending to be chevron-shaped dorsally, anterior
and posterior series forming a relatively small angle at
their intersection; hinge line short, straight; beaks small,
tending to be slightly opisthogyre.
Discussion.—Regressions of height and length of Glycy-
meris subovata are variable. Either height or length may
§ ‘ y
be greater at all observed growth stages. Correlation is ac-
cordingly not good and the combination of these characters
1s not used in the statistical study.
The width of the ligamental area decreases with respect
to length of ligamental area in Glycymeris subovata from
lower Yorktown to Duplin time. The combination y=
WI, x = LI for G. subovata from early Yorktown samples
1, 2,4, 15) and G. swbovata from Duplin equivalents (sam-
ples 3, 5, 7) are compared to G. americana from Natural
Well. The samples from early Yorktown are all statistically
distinct in the “B” combination whereas none of the sam-
ples from Duplin equivalents are distinct in this combina-
tion of characters (Table 11).
The chevron grooving on the ligamental area seems to
decrease in prominence with dec reasing geologic age also.
Much variation in shape and ornamentation is present in
Glycymeris subovata. The shape varies from high, short to
nearly orbicular forms. At the Williamston, North Carolina,
locality several individuals show a produced posterior mar-
gin. This posteriorly produced form was considered by Dall
to be a distinct “variety”, G. swhovata “var.” plagia, but it
is probably an ecophenotype because the form is variable
and restricted in its distribution locally but has been found
in Florida faunas as well as in North Carolina, Virginia,
and Maryland. G. waltonensis Gardner, 1926 was used for
the posteriorly produced form by Gardner which she dis-
tinguished from Dall’s “variety” on the basis of its smaller
size, less inflated form, and its more flattened intercostal
areas. These differences are not considered distinctive
enough in the variable Glycymeris subovata to be syste-
matically important.
12 PALAFONVOGRAPHICA AMERICANA (V, 34)
The ornamentation in Glycymeris subovata most com-
monly consists of broad rounded ribs with narrow inter-
spaces. In some forms, particularly at localities along the
James River in Virginia, a tendency for sharply crested ribs
is seen. At various localities an occasional specimen shows a
tendency to develop a secondary rib or two on the costae—
the position and prominence of these secondary ribs is
variable and because of the lack of uniformity are sug-
gested to be environmentally induced. No specimen was
found to have so regular secondary ribs as the figured speci-
mens of G. drymanos grapta Gardner, 1926. However, Gard-
ner (p. 37) stated that the secondary ribs in her subspecies
are variable. This form may also be an ecophenotypic G,
subovata. G. drymanos was distinguished from G. subovata
by Gardner in being smaller, heavier, and more inflated;
these characters are not consistent enough to be of value.
Glycymeris subovata tuomeyi Dall, 1898 is characterized
by flattened costae and relatively broad, flattened inter-
spaces. Specimens showing these features are common in
collections from Morgarts Beach and Boykins, Virginia, and
at Murfreesboro, North Carolina. The form is rare at Kings
Mill Wharf, Courtland, and Yorktown, Virginia, and at
Natural Well, North Carolina. The characters of this form
too may be environmentally controlled but the characters
are more consistent than the others discussed.
Hypotypes.—U. N. CG. Cat. Nos. 3550-3553.
Range.—Miocene.
Localities.—Nos. 5, 6, and 9-21.
Glycymeris pectinata (Gmelin), 1791
Plate 5, figures 7, 8
Arca pectinata Gmelin, 1791, Systema Naturae, vol. 6, p. 3313.
Pectunculus aratus Conrad, 1841, Amer. Jour. Sci. vol. 41, p. 346;
1845, Fossils of the Medial Tertiary of the United States, p. 62
pl. 34, fig. 2.
Glycymeris charlestonensis Holmes, 1860, Post Pliocene Fossils of
South Carolina, Russell and Jones, Charleston, South Carolina,
p. 16, pl. 3, fig. 5.
G. pectinata (Gmelin), Dall, 1898; Wagner Free Inst. Sci, Trans.,
vol. 3, pt. 4, p. 612.
G. (Tuceta) aratus floridana Olsson and Harbinson, 1953, Acad. Nat.
Sci. Philadelphia, Mon. 8, p. 3, pl. 1, fig. 5, 5a; Dubar, 1958,
Florida Geol. Sur., Bull., No. 40, p. 153, pl. 1, fig. 8.
Diagnosis.—Shell truncated
trigonal, small, obliquely
posteriorly; ligamental area marked with closely spaced
chevron markings, wide in relation to length; costae coarse,
broadly rounded, without striations, interspaces about as
broad as ribs; teeth in continuous series, forming acute
angle dorsally, subequal throughout, none chevron-shaped;
hinge line short, straight; crenulations large; beak small,
slightly opisthogyre.
Discussion.—In ornamentation, slight opisthogyre attitude
of the beaks, and chevron markings on the ligamental area
this species shows similarity to Glycymeris subovata. How-
ever, even young specimens of G. swbovata can be dis-
tinguished from G. pectinata. Young individuals of G,. sub-
ovata have nearly round shells while in G. pectinata the
valves are truncated posterio-dorsally and sharply rounded
anteriorly so that the shape is trigonal and noticeably high-
er than long. The costae of G. pectinata have a greater
relief and are more widely spaced than in typical G.
subovata and the crenulations of G. pectinata are larger
and less numerous.
Glycymeris duplinensis Dall, 1898 is similar in size, shape,
and dental series to G. pectinata. The species, specimens of
which were not collected by me, differs from G. pectinata in
having the costae centrally grooved ventrally; the costae are
coarse and widely spaced as in G. pectinata.
Glycymeris pectinata is a common shallow-water species
from North Carolina to both sides of Florida and the West
Indies (Abbott, 1954, p. 348). Maury (1920, p. 21) reported
it from Hatteras, North Carolina, to Nicaraugua, at a depth
of 2-175 fathoms.
Hy potypes.—U. N. C. Cat. Nos. 3554, 3555.
Range.—Duplin Miocene? Waccamaw Pliocene—Re-
cent.
Localities.—Nos. 1, 2, and 3.
TABLE 11
Comparisons of Regression Coefficients in Glycymeris
Sample | 5 6 8 10 11 13 14
no. ABC ABC ABC ABCD ABCD ABCD ABC ABC
2 000 X—X
3 x 0x
| X—X
5 000 === ()
6 +++ +00 +++ ++0
7 000 000 —00
8 00+ 000 ——0 +000
9 O++ +00 0+++ 000+
10 —000
1] —()i0 ++00
2 0+0 —(00 000
ld 000
15 X—X
16 000
ee EEEEEEEEEIEEEIEIEINEE EIEN INES dtientestettenetn
Significance level = 5%, 2 sided.
Mip-ATLANTIG
Explanation of ‘Vable 11
Symbols:
A. y =convexity (C/2), x length (Lt).
B. y = width of ligamental area (WI), x = length of liga-
mental area (LI).
C. y = distance from anteriormost tooth to beak, (T.-B) ,
x = distance from anteriormost tooth to posteriormost
tooth (T.-T,).
(T2-T,) .
D. y = distance from posteriormost tooth to beak, (T4-
B), x —distance from anteriormost tooth to posteriormost
tooth (T:-T,) .
Abbreviations used in text:
Lt. = length of valve.
Ht. — height of valve.
W1 = width of ligamental area measured along ligamen-
tal area dorsoventrally.
Ll = length of ligamental area measured parallel to
hinge.
C/2 = convexity of one valve = width of one valve. The
term convexity is not appropriate in that the measure-
ment is no index to valve curvature.
T.-B = distance from anteriormost tooth to beak.
Ty-B = distance from posteriormost tooth to beak.
T.-T, = straight line distance from anteriormost tooth
to posteriormost tooth.
Notation for Table:
xX —no test made for this combination.
--—the value of the regression coefficient in the
sample in the column is significantly greater than that
of the sample in the row. For example, the regression co-
efficients for sample | are all greater than the correspond-
ing values for sample 6 in Table 11.
—= the value in the column is significantly less than
that in the corresponding row.
O —no significant difference between sample in the
row and the sample in the column, indicated by the t-test.
Equations:
Sample no.
1 A.y=0.258x — 0.049
B. y = 0.215 x — 0.020
C.y = 0.643 x + 0.011
Glycymeris subovata,
Yorktown formation,
Claremont, Va.
.y = 0.291 x — 0.171
B. y = 0.234 x — 0.040
(Gy y= 0.610 x + 0.119
Glycymeris subovata,
Yorktown formation,
Kings Mill Wharf, Va.
8) C. y = 0.207 x — 0.002. G. subovata, Yorktown
formation, Colerain,
INEE:
LP ERTIARY
ARCAGEA:
iS) 3
10
12
13
a
16
~
Birp
1. ¥ = 0.248 x — 0.083
-y = 0.232 x + 0.102
-y = 0.172 x — 0.022
1. y = 0.597 x + 0.058
-y = 0.177x + 0.131
-y =0.120x + 0.029
. y = 0.516 x + 0.010
y — 0.217 x + 0.100
\—— 0.181 x — 0.010
1. ¥ = 0.625 x + 0.012
.y = 0.262 x + 0.047
.y = 0.192 x — 0.065
p= 0.577 x + 0.018
y = 0.640 x — 0.055
Ane
-y = 0.227 x + 0.077
y= 0.090 x + 0.514
1. y = 0.528 x + 0.098
-y = 0.535 x + 0.066
y — 0.340 x — 0.251
5 = O10 2.— OA
1. Y = 0556 x + 01071
D. y = 0.608 x + 0.007
:. y = 0.250 x + 0.071
-y = 0.128 x + 0.008
y — 0.476 x + 0.110
y — 0.592 x — 0.002
y = 0.318 x — 0.015
y = 0.140 x — 0.019
i. ¥ = 0.595 x + 0.033
y — 0.376 x — 0.522
y =0.245x — 0.214
zy = 0.718 x — 0:474
y = 0.312 x — 0.290
y — 0.180 x — 0.063
1 ¥ = 0.599 x + 0.066
y= 0269 ONL?
-y = 0.393 x — 0.125
B.)
. Y = 0.580 x + 0.083
y = 0.395 x — 0.611
G. subovata, Yorktown
formation, Worrels Mill
Pond, N.C.
G. subovata, Duplin
marl, Natural Well,
INGGe
G. americana, Duplin
marl, Natural Well,
N.C.
G. subovata Duplin
marl, Lumberton, N.C.
G. americana (asymmet-
rical subset) , Wacca-
Acme,
maw formation,
N.C.
G. americana (symmet-
rical subset) , Wacca-
Acme,
maw formation,
NGG:
G. americana (asymmiet-
Wacca-
maw formation, Old
Dock, N.C.
rical subset) ,
G. americana (symmet-
Wacca-
maw formation, Old
Dock, N.C.
rical subset) ,
Glycymeris anteparilis,
“Trent formation,” Sil-
verdale, N.C.
York-
Boy-
G. — lentiformis,
town formation,
kins, Va.
G. parilis, Calvert for-
mation, Plum Point,
Md.
G. subovata, Yorktown
formation, Boykins, Va.
G. pectinata, Waccamaw
formation, Acme, N.C.
All possible combinations of species and sample compari-
11 PALAEONTOGRAPHIG
sons were not made. Only those closely related species or
those showing convergence were compared.
Samples 2, 3, 4, and 15 of Glycymeris subovata were com-
pared to G. americana from Natural Well (sample 6) only
for the combination “B” to show that the regression coeffi-
cient for y= WI, x = LI] decreases with decreasing relative
age.
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APPENDIX
Appended Tables of Raw Measurement Data (in millimeters) of
Representative Samples
Symbols:
R—right valve
L—left valve
Ht—height of one valve
Lt—length of one valve
W1—width of ligamental area
Ll—length of ligamental area
C/2—convexity (width) of one valve
‘T2-B—distance from anteriormost tooth to beak
‘T.-B—distance from posteriormost tooth to beak
T.-T,— straight line distance from anteriormost to posteriormost beak
TABLE 12
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822 ("A. improcera" subset),
Natural Well, North Carolina
Specimen Ft Lt Ww. c/2 To-T),
R1 13.6 0.9 “8
R2 15.5 1.0 5.5
RG 8.9 0.4 M
R4 13.6 0.9 13.3
R5 9.3 O.4 10.2
Lé 13.0 0.7 12.0
R7 13.3 0.7 1.0
ne 15.5 0.9 13.7
Rg 13.0 0.6 UW.1
110 10.0 Ov 10.6
m1 73 0.3 6.9
Ri2 2.5 0.3 29 Toh
13 7.5 0.5 bil 7.0
Lu 9.7 0.6 35 G1
Ls 10.6 Ouk 10.1
116 10.0 0.5 8.3
R17 11.0 O.E 10.8
Mean value 1.1 16.4 O. é 11.0
“See title page of appendix for meaning of symbols.
TABLE 13
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822 ("A. buccula" subset),
Natural Well, North Carolina
Specimen Ht Lt (1 /2 T-T),
R 1 13.4 1.3 6.1 12.7
L2 13.4 1.0 6.0 12.7
L 15.6 1.3 6.3 13.0
L& 13.1 0.9 5.3 10.8
L5 13.0 1.2 567 2.1
L6 2.3 1.0 525 11.5
R7 11.5 0.8 4.9 10.1
R8& 12.9 0.9 5.6 10.9
RQ 15.2 1.4 6.7 12.5
110 13.7 1.1 6.0 el
R11 13.6 1.1 6.2 13.6
R12 U.1 1.3 6.3 2.7
R13 15.5 1.2 6.5 12.0
Ld 13.9 1.2 6.3 11.5
R15 11.0 0.8 5.8 2.1
L16 12.6 0.9 4.7 9.7
RL? 10.8 0.9 4.8 103
Mean value 13 18.3 1.1 8 11.7
TABLE 13a
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822,
Natural Well, North Carolina
Specimen Ht Lt Ww c/2 ToT,
Rl 15.0 19.1 2.1 7.0 1.7
L2 W.2 20.0 1.2 6.3 1
L3 12.1 U4 0.8 5.0 965
R& 12.6 16.6 1.8 5.8 10.1
L5 22.0 Ww.6 1.0 5.1 965
R6 11.8 15.5 1.4 4.6 10.6
L7 10.9 15.5 0.8 4.5 10.6
L8 13.0 17.2 1.2 5.8 10.6
L9 u.1 16.3 0.5 Sel 4
R10 4.0 18.1 2.0 6.2 1.8
Ru 91 12.9 0.7 3.9 8.0
112 12.0 16.0 1.0 4.6 965
na3 2.1 15.0 1.9 5.5 10.2
Lu 13.6 18.2 1k Sal 1
R15 15.6 22.0 1.2 6.3 13.7
hue 4.5 19.5 1.7 6.4 12.8
117 10.5 15. 1.0 hel, 9.1
118 13.3 17-4 Tel 6.0 1.7
119 10.0 4.6 0.4 4.8 9.0
20 8.0 u.3 0.4 3.5 8.0
Mean value 2.3 16.5 1.2 5-3 10.6
ree ees
Mip-ATLANTIC ‘TERTIARY ARCACEA: BIRD
TABLE ly, TABLE 17
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822, Measurements of Sample of Anadara (Anadara) transversa (Say), 1822,
Walkers Bluff, North Carolina Atlantic Beach (Recent), North Carolina
Specimen Ht it wi c/2 T2-T, Specimen He Lt W1 c/2
Tal 19.1 27.6 0.9 8.0
Rl 21.0 31h 1.5 8.1 21.0 > ;
R2 19.3 27h 1.6 8.5 19.0 u 5 ie 28.5 1k 8.4
L3 17-1 25.0 1.2 722 16.5 Ti aia Be oe ae i)
Ls 16 22:0 12 73 bis RS 16.6 25.6 1a at 12
ie iv A R6 19.1 28.0 1.5 B.2 18.9
L6 21.5 29.0 1.8 9.5 19.2 oa aeee . a i
L7 20.1 26.8 167) 9.1 16.8 ai rie zy a 8.4 16.3
RB 17.2 sols 1.5 Tol 15.5 ths Tas . 0. 565 15.0
R9 21.9 29.5 2.6 9.6 20.9 10 noe aie Os 3.6 9.7
R10 23.8 Bhs ols 3.0 1 25h aa ae a 0.7 5.2 11.7
ieee 21.0 29.5 2.2 8.6 19.5 0 21.2 0.6 53 W.4
Ru2 20.9 3he? 2.0 8.6 23.7 i 17-4 27.8 1.7 765 16.6
Ww 18.6 232k 2.0 8.3 17-6 3 12.5 19.0 0.6 5.0 1.8
jay 17.1 27-2 1.5 8.4 16.8 ze 1.8 20.2 0.8 5.9 1
115 15.8 23.2 0.6 6.4 W.7
115 13.3 20.0 0.9 507 By ay
R16 19.3 29.7 2.1 8.0 19.0 7 1.0 20.5 0.8 6.4 4
117 21.0 3he1 2.2 9.6 21.1 10.2 16.3 0.4 4.2 9.2
R18 10.7 17-1 y 0.9 4.3 1.4 le 4.8 21.1 0.9 6.6 2.6
m9 19.5 30.6 2.0 8.4 19.0 i a0 18.2 0.6 4.5 25
R20 18.5 29.5 2.1 706 19.6 10. 4.0 Ob 4.0 9.8
Mean value 18.6 2726 1.8 8.1 18.2 Roane le Web 21.7 0.9 6.0 13.7
a ee ee er ee ee
TABLE 15
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822, TABLE 18
Bomb res eyanoxt nec ano ns Measurements of Sample of Noetia (Kontia) incile (Say), 1824,
King's Mill Wharf, Virginia
Specimen Ht Lt W1 c/2 T2-T,
a 276k 33.8 2.3 1.3 20.8 Specizen He ze "1 a ie 13-3
L2 28.7 38.1 3.1 1
R3 31.3 42.6 2.5 13.2 x 3 31.0
Rh 27.0 38.4 1.8 9.5 sees)
L5 22.6 28.9 1.5 8.9 ‘ ‘ 26.1
R6 30.6 41.3 4.3 13.5 - Zhe
L7 22.6 30.5 1.5 8.5 - 2 28.
LB Qel 33.6 Toy 8.9 aie 25-0
L9 23.0 33.0 1.8 10.3 Ree Be
120 30.4 10.7 2.5 23 ae 28-6
inee 27.0 3565 1.7 10.1 ae ait
12 27.0 35.5 2.1 10.5 ah 28.3
113 25.5 3h 5 1.9 11.1 19.4 a cee
1, 28.5 707 1.9 2.1 2345 296
Ras 24.0 31.3 1.6 967 19.2 a 21.4
raé 27.8 36.1 1.5 11.2 22.5 a a
7 20.6 27.8 1.5 22 17.0 re 25.6
112 22.4 31.2 1.2 9.7 19.2 18.0
Re 28.7 36.6 2.0 1.6 23.7 Ry 22.0
120 25.8 32.1 2.0 1k 21.4 te ey
Mean value 2604 35.0 2.0 10.7 21.3 120° 20.1
Mean value 2h. 3.0 3.1 4.6 6.0
TABLE 16
Measurements of Sample of Anadara (Anadara) transversa (Say), 1822,
James City, North Carolina
TABLE 19
" Measurements of Sample of Noetia (Eontia) trigintinaria (Conrad), 1862,
ppcereen Le ie Le C2 TT Natural Well, North Carolina
L1 Bleeds 54.0 5.0 Ww.5 Bhd
R2 32.6 52.7 3.5 12.8 30.2
L3 30.6 50.1 3.0 2.2 28.6 Specimen Ht It wi Ll HPM T2-B
Lh 19.2 29.5 1b 8.2 17.5
ae 36.1 53.6 Abel 15.2 30.0 R1 21.5 33. 2.8 16.0 5 al 8.9
L6 33.7 49.1 3.6 4.6 29.9 R2 10.0 13.4 lb Tol 3.0 4.8
iy 25.8 40.7 1.8 10.5 25.0 L3 16.0 25.2 2.7 11.5 5.0 702
ae 27-1 408 2.5 u.1 2726 La 15.4 23.8 2.5 8.7 4.7 6.4 13.6
Ra, 33.6 AT 0b 3.3 3.2 28.0 R5 10.4 15.9 1.5 6.8 3.5 4a B.2
R10 23.9 36.6 2.1 10.0 22.9 R6 11.4 17-4 1k 6.1 3.1 49 9.6
Ri 17-5 2944 1.0 6.1 18.1 L? 18.1 30.4 2.7 12.5 5.0 766 18.0
Lu 25.2 370 2.0 10.1 23.0 RB 22.0 18.0 1.2 Tole 3.8 565 10.0
RB 28.6 45.0 2.6 10.8 27-3 L9 73 11.6 0.8 3.8 2.0 3.0 6.2
RU, Bb 19.1 0.7 542 1.6 R10 15.6 25.1 2.0 10.1 heb 6.6 3.2
R15 9.5 15.2 0.4 3.2 9.8 RIL 2.0 18.8 1.8 8.5 3.5 5.5 10.5
Ra6 16.6 2h6 0.9 6.2 15.5 112 5.8 8.7 0.6 3.3 1.6 2.7 49
R17 1.5 18.4 0.5 he? 2.1 RB 22.2 17.8 2.1 8.5 34 5.0 1.3
lus 18.7 28.6 1.0 Tole 18.3 RU, 10,0 W.5 Ter 6.6 3.0 3.3 8.1
R19 27.1 42.7 3.6 1.2 26.8 115 9.6 15.1 1.2 5.8 2.6 Ba 8.7
120 16.5 26.4 0.7 6.0 B.4 R16 7.0 10.6 0.6 rest 2.1 3.0 5.6
Mean value Zed 37-2 2.2 9.6 22.5 Nean value R21 18.7 1.6 729 365 5.2 10.5
48 PALAEONTOGRAPHICA AMERICANA (V, 34)
TABLE 20 TASLE 23
Measurements of Sample of Noetia (Sontia) platyura (Dali), 1898,
Measurements of Sample of Noetia (Eontia) carolinensis (Conrad), 1862, Town Greek sitorthCGasaleras
Black fo North Caroline
Specimen Ht Lt W1 Tht HEM To-B 1,3 Specimen Ht Lt wi 1 HPM T2B 1,-B
Ht 43.0 59.1 5.6 33.6 11.7 20. z R1 140.6 58.3 Boel 30.4 11.5 19.1 23.0
R2 37.0 49.6 ih 30.6 10.7 18.5 5 L2 12.9 60.0 5.5 28.8 13.9 20.6 25.2
L3 390k 58.1 6.4 33.6 Rl 20.7 3 L3 42.3 55.3 5.0 25 1.4 19.9 22.3
L4 41.6 60.2 8.1 29.8 2.0 19.3 2 R& 40.0 63.7 6.0 292k 2.4 20.0 23.6
L5 38.3 Shel 5.5 30.0 10.5 18.0 O.1 L5 39.0 60.0 5-0 25.0 10. 17.4 21.0
R6 32.6 4725 3.3 20.8 8.8 543 ) L6 50.6 1705 8.8 39.6 15.3 23.5 30.4
R7 35.1 49.7 305 2hed 945 17.5 6 R7 40.0 55.6 43 25.1 10.0 17.5 19.6
R8 3764 49.0 4.7 26.5 10.6 16.8 19.3 L838 45.4 69.4 6.4 32.0 12.6 22.0 26.4
R9 20.0 28.2 11 10.6 5-6 €.8 9-9 Lg 39.8 58.5 6.0 26.1 10.7 18.9 21.9
R10 25.7 30.6 2.0 15.7 rc) 13.1 13.8 110 42.3 59.6 6.4 32.6 10.9 19.8 23.7
jue 36.0 53.8 4.8 26.7 10.5 16.0 19.5 lal 36.5 148.3 5.1 24.1 8.9 15.8 20.4
Li2 34.8 51.3 can 2723 10.1 17.2 18.9 R12 43.0 61.0 5.7 25.7 12.0 20.6 Zyel,
13 26.7 37.2 2.5 15.1 7.6 2.6 U2 113 41.8 59.8 56k 26.9 10.3 18.7 23.3
Lu 36.0 47.6 3.7 21.9 9.2 16.2 LoS RU, 42.1 5766 4.9 25.6 1.6 18.3 2hel
R15 31.9 47-1 3.2 23.5 8.5 15.6 Ti5 ras 49.5 77.0 13.3 43.1 4.7 24.0 33.6
116 43.0 61.7 529 33-0 2 19.8 23-6 116 42.3 61.9 6.4 27.2 10.5 18.2 27.0
L17 29.7 41.7 2.9 18.6 8.0 12.8 14-6 7 41.7 69.0 4.8 30.1 10.6 22.1 26.7
int) 39.5 60.3 Berd 3264 1 19.0 25-0 nae 52.2 Tal 8.5 38.3 Web 24.6 26.8
rg 10.0 53.6 545 31.7 Lk 19.6 21.0 R19 40.7 62.6 6.2 28.0 1.1 21.9 23.7
R20 39-7 5726 6.4 30.9 u.8 18.3 2078 R20 Lh .2 67.9 8.3 38.0 12.6 20.7 27.0
Mean value 3524 49.9 4.5 25.8 9.9 16.8 18.8 Mean value 12.8 62.5 6.4 20.0 11.9 20.2 2he7
NS cl TABLE 24
Measurements of Sample of Noetia (Eontia) limila (Conrad), 1832, Measurements of Sam ia) pot S
Noetia (Eontia) lima : e' ple of Noetia (Hontia) ponderosa (Say), 1822
James City, North Carolina Atlantic Beach (lecent), North Carolina
x
i
z
E
z
5
z
a
u
2
b
Specimen Ht Lt Wi ll HPM 7,-8
Ri Bheb Shab 4.5 25.1 10.6 16.4 20.9 L 5
R2 28.5 23 4.0 18.9 eu W.9 19.2 re Bre ae. ok) ug ate
R3 34.7 53.5 2.9 23.0 10.3 16.5 21.9 25 ga 2: 1e1 8.7 ber
Rk 36. a 6.7 53.8 2.0 ink 24.3 Li 34.2 3.5 16.2 ark R3
L5 17.9 29.5 2.0 io 5.6 8.9 9.8 ut ee 3.5 ae 2 233
R6 28.7 41.2 2.7 15.0 769 2.7 1.4 me 16.2 Lo 6.3 305 70
L7 45.0 TL 8.1 34.0 12.5 211 27.0 a ae ae oe Fe es
Le 36 52.1 3.9 23.1 9.2 16.3 19.8 Le 20.5 1.9 7:2 5.0 9 811
L9 34.6 56.9 4.7 26.1 10.8 17.0 21k 29 28.8 3.1 3.2 6:5 12 Bh
R10 27.7 471 3.2 17.3 Qeh 3.5 16.6 e10 eG 5.6 2427 9.3 21 19.1
11 32:4 56.0 ret 21.3 10.0 15.6 21.8 rai page ac al ee # oe
m2 32.6 5d 135 hak 10.0 15.5 19.0 a2 30.4 2a rem 7.6 B wk
13 29.0 45.2 3.8 19.8 8.0 Wit 16.2 La 2915 2:7 lie bok B 1:2
1s 31.5 51. 4.6 24.8 8.8 1.9 19.4 Th Baae ah aie a 7 aaa
15 40.9 67.8 7.8 32.8 1.7 18.7 25.0 nas 21.0 1.2 B16 hig 9 8.6
R16 35.5 58.0 5.5 28.5 10.8 175 21.1 Rae aaa aa are ies A asa
RL? 29:0 45.5 8.3 18.9 1.9 3.0 174 7 20.1 1.6 8.8 5.0 9 8.5
Rie 21.3 3.5 1.5 22.0 5.7 10.5 1.5 a) ieee ne a an Z ae
iat) 24.8 39.6 2k 18.0 15 13 Wye2 Rg Ba iG ae Ag i ae
R20 31.0 49.7 3.6 21.7 Fed G1 17.5 R20 18.2 1.2 7:7 5.0 7 726
Mean value 31.5 50.6 42 22.5 963 15.0 18.9 Nean value 25.5 31.8 2.3 11.2 6.2 u.7 10.4
TABLE 22
Measurements of Sample of Noetia (Eontia) platyura (0al2), 12898, GRELE 25
SEES TANG Wea EERO Measurements of Sample of Glycymeris parilis (Conrad), 1842,
Plum Point, Maryland
Specimen Ht Lt wi ll HPM T,-B
R1 3hek 52.0 hel 2.5 9.3 21.0 Specimen Ht Lt wa a C2 T2-t, TB
L2 bel 63.0 71 31.0 11:0 29.5 .
R3 43.5 Shel 6.5 24.6 10.9 2.5 Ril 86.4 82.6 8.5 47.0 28.0 61.8 38.5
L4 22.2 29.7 2.3 2.0 5 oh 12.7 R2 84.6 24.6 6.4 40.1 23.0 5703 32.6
Ls 46.5 63.4 8.6 31.6 10.7 29.0 RG alk 79.5 bh 42.6 22:1 560k 34.0
R6 23.0 31.5 2.6 18.0 61h 15.5 Rh 20.4 21h lo 7.8 he7 Us.7 9.3 .
R7 40.5 50.5 6.1 27:5 9.5 23.3 R5 30.5 31.7 le 3.5 nT 22.9 15.1
L8 42.5 52.6 6.0 23.4 ab ri 21.3 L6é L364 7 2.3 18.2 10.5 31.0 18.5
L9 36.6 hot 610 26.0 10.1 22.8 L7 Tu 65.0 5.8 35.0 16.2 48.0 2944
£10 45.6 56.6 6.5 28.3 10.6 29.7 Ra 81.6 79.6 bie 12:0 21.8 5607 34.8
inbt 3.2 Tee 52h 21h 8.8 12k L9 81.5 78.6 6.6 3704 21.7 53.8 33.9
RZ sch 65.0 615 32.7 1212 26.8 120 81.5 80.0 6.2 39.4, 20.0 55.6 34.6
Mean value 38.2 51.0 5.7 25.1 . 17.3 22.8 Mean value 66.2 64.8 5.2 32.3 17.6 4508 28.1
Mip-ATr. TERTIARY ARCACEA: BrirD
TABLE 26 TABLE 29
Measurements of Sample of Glycymeris anteparilis Kellum, 1926, Measurements of Sample of G: ris americana (Defrance), 1826, (symmetrical subset)
Silverdale, North Carolina Old Dock, North Carolina
Specimen Ht Lt wr ll c/2 Specimen Ht Lt wh ln c/2 T)-Ty, T-B 1,-B
Ll 48.0 51.1 3.0 21.8 16.2 B45 20.9 Li 48.2 50.0 2.5 19.5 14.0 33.2 19.3 16.0
ti? 28.5 29.5 1.5 B.1 8.6 21.7 Bl L2 36.8 40.3 1.5 10.5 91 27-4 UW.7 8.4
R3 41.6 45-0 2.1 20.6 3.7 32.0 17.4 RG 19.4 21.0 1.0 Tol, 5.8 15.0 7.6 13.8
L4 52.6 54.0 3.4 26.9 18.6 39.6 2405 L4 30.0 32.1 2.0 2.0 7.6 22.7 13.5 10.2
R5 32.0 34.0 2.0 15.6 9.5 25.5 16.0 R5 25.0 28.0 1.5 9.8 8.0 17.5 10.0 15.6
RG 4.6 45.6 3.2 22.0 13.3 32.8 20.0 R6 37.0 40.0 2.4 4.6 10.0 27.0 15.6 7.6
R7 36.6 37-3 1.8 17.2 11.0 27.4 16.0 R7 27.3) 18.5 0.9 7.6 13.5 8.4 726 6.5
La 40.1 42.2 2.4 20.1 2.6 31.1 19.2 R8 15.7 16.8 0.8 6.2 4.6 D4 7.0 13.0
a) 26.6 28.0 1.1 11.1 9.3 18.9 n.1 RQ 31.6 Buel 1.3 13.5 8.0 23.1 12.8 706
110 48.2 49.2 3.6 2.8 15a 36.0 22.4 R10 17.5 19.1 0.9 8.0 5-6 2.0 769 B.1
R11 35.5 36.9 2.0 15.3 2.3 25 oh 4.6 pant 48.0 51.0 2.6 23.6 W.6 39.1 21.6 9.8
112 40.2 42.4 2.6 13.0 2.0 30.1 18.5 li 29.5 32.4 1k 91 8.4 22.4 13.0 6.0
13 33.6 36.5 2.3 15.1 10.3 26.4 16.2 13 23.1 25.6 1.2 8.6 6.5 17.3 10.3 el
RU 3403 34.2 2.2 15.0 13.5 2.6 We3 ALL 13-4 Wy.1 0.8 5.6 4.8 9.5 5.5 15.6
115 39.6 41.5 2.7 18.2 13.1 30.0 19.0 R15 16.1 18.0 0.9 7.0 5.8 12.0 8.0 705
116 eps 28.0 1.0 4 768 19.6 1.6 116 36.0 40.5 1.6 15.0 10.6 27.5 15.5 9.0
R17 35.6 36.6 2.4 16.1 1.0 27.3 17.3 117 17.0 19.0 0.9 5.6 5k 12.6 7.6 19.2
118 36.1 36.4 2.3 16.0 11.0 26.6 17.0 1s 21.0 22.6 1.1 Tbe) 6.6 15.6 9.0 23.3
R19 29.5 30.7 Lk 2.3 10.2 21.0 Rh 119 43.2 46.5 2.5 16.5 13.0 31.6 17.8 20.6
20 38.9 40.0 2.1 18.3 15.0 29.8 17.2 120 56.5 61.5 3.6 23.6 17.0 40.4 22.6 22.9
R21 10.2 10.3 0.5 3.0 3.5 6.8 4.6
Mean value 29.1 31.5 1.6 11.6 8.6 21.6 Rob 12.6
Mean value 36.1 3766 2.2 16.8 11.8 27.0 16.4
TABLE 30
Measurements of Sample of Glycymeris americana (Defrance), 1826, (asymmetrical subset)
TABLE 27 Old Dock, North Carolina
Measurements of Sample of Glycymeris lentiformis (Conrad), 1835,
Boykins, Virginia
Specimen Ht Lt 1 Ll 0/2
a 2
Specimen Ht Lt wi a c/2 TT TB ae rea aie Aes 2
R3 2 3.0 18.9 5
hal 60.2 63.0 8.1 37-5 19.5 51.5 32.0 R4 31.8 2.3 1.0 9.
L2 50.6 53.1 5.0 29.5 13.8 bel 25.0 R5 50.6 4.0 23.5 15.5
L3 52.0 53.2 3.1 27.1 13.8 42.6 25.7 R6 78.0 10.0 46.5 28.2
Rh 50h 51.5 hel 25.0 15.6 40.5 26.5 L7 52.3 3.6 2761 17.1
L5 51.1 55.1 4.6 2h5 13.1 43.6 25.4 Le 40.0 2.6 18.8 13.9
R6 51.0 51.5 5.8 28.8 W.6 bh 28.6 R9 48.4 3o4 22.1 25
R7 39.5 bly oly 2.4 15.9 10.4 33.8 19.0 110 40.2 3.0 18.0 1.9
LB 50.5 51.6 5.0 30.3 Yl Ly.5 29.0 Rll 27.0 Lek 12.2 8.0
L9 56.5 56.1 6.0 34.0 17.8 46.6 30.1 Li 22.0 1.0 9.1 71
110 52.6 5263 4.5 25.4 We 4h «0 25.4 113 36.6 2.5 w.9 1.1
mm Shel 5701 6.0 31.0 16.2 W5.7 27.9 RU 53.0 364 23.8 15.0
R12 50.8 52.0 5.0 30.5 15.2 A) 25.6 115 550k 3.7 27.5 17.1
R13 49.1 51.9 3.8 26.0 13.5 3901 23.0 R16 45.0 3.1 20.5 13.0
Ly 45.6 48.7 3.5 25.5 3.1 3926 2hel RL? Bed 5.2 32.6 22.5
115 47.0 47-6 hel 30.0 15.5 39.6 23.8 11g 58.5 3.2 25.0 16.5
R19 38.9 2.6 17.0 1.4
Mean value 50.7 52.9 4.7 28.1 s.7 42.9 26.1 R20 34.6 2.0 4.2 9.8
Mean value 4507 Le. Br 21.0 13.9 19.4
TABLE 28 TABLE 31
Measurements of Sample of Glycymeris americana (Defrance), 1826, Measurements of Sample of Glycymeris americana (Defrance), 1826, (symmetrical subset )
Natural Well, North Carolina deme, North Carolina
Sean Ht a wi a c/2 ToT, ped Specimen Ht re wy Ll c/2 ToT, T9-B
5 R1 58.0 3.0 2he1 W.7 41.0 22.0
ue Bee bea 1.8 ae ae R2 58.0 3.7 28.3 15.7 4703 27.0
13 28.9 sare ane 10.3 aio) R3 54.8 2.6 21.6 14.6 41.1 22.0
Be 3814 ico 21 7 es L4 41.0 204 15.6 12.0 28.6 16.0
RS 20.1 218 Lo 6.0 iG R5 42.3 2.0 16.k 10.8 29.8 16.2
Lé 20.5 22.0 V3 6.8 6 Lé 12.5 0.5 41 3.8 8.8 566 2
L7 3.0 37.8 Vs 9.5 77 R7 40.3 2.1 17.0 2.1 30.0 17.0 15.7
La Bi,.0 86.0 615 360, 16.5 Le 17h 0.9 705 5.0 12.5 705 Tob
L9 19.5 5L.3 317 20.0 0 L9 18.2 0.7 8.0 ee) Bek 7.8 7.8
F 5} . neg
0 71.5 7210 507 36.2 cTiht R10 28h 316 1.8 7-7 20.1 n e
RL 7767 80.0 5.0 38.8 ue ae ah oe LED aot aoe ee {ee
12 33.0 360k Lek 9,3 Gin R12 15.h 0.9 568 3.8 ely oe)
13 39.1 1326 23 ae Bik 113 Web 0.6 567 bel 9.9 6.1 5.8
DL 163 50.4 23 EW Lu, 18.2 0.) 8.6 5.8 3.7 8.5 ie
1s 55.6 Cait eet rl 15.2 0.7 7.0 heb 10.8 7.0 oh
Le 22.6 26.0 4 R16 LOK 2.8 20.1 23.0 3h.0 19.4 19.9
7 26.9 30.6 Er R17 3725 2.0 16.4 9.0 27.6 15-4 15.4
18 36.6 haa nas rie 26.0 1.7 l..e 7.0 18.7 21 10.7
At) 31.9 36.5 Tee 119 20.0 0.9 9.6 6.4 1.5 8.6 8.1
720 80.5 a0 63 120 21.6 1.2 9.0 6.0 15.8 9.1 can
Mean value 43-7 h7ed ol Vk : 3.2 19.6 ee 128 28 e3 apek ea 28
+1)
¢
4 AMERICANA (V,
at
RAPHIC
,
PALAEONTOC
50
TABLE 32
TABLE 35
King's Mill Wharf, Virginia
Measurements of Sample of Glycymeris subovata (Say), 1824,
Aeme, North Carolina
Measurements of Sample of Glycymeris americana (Defrance), 1826, (asynmetrical subset)
Lt Ww Ll c/2 ToT, TB
Ht
Specimen
",
Lt Wl Ll c/2
Ht
Specimen
oH Baoreu amendmen
qergy gongs
ARAN
QVWLIINHeYHI9a awongz0
Sdsaacagsgggy Del alate ala
AMNAadaR ANANMANMA AMG
QIIQVTHQIENO sd se sHe MAGS
SqHSASRRR AAG AMG Gas Sage
THON gd Hagydeensoawvonn
Seer esdesssenssoagsr
AINA MAAAMAMASA
Sie ined aN aN hon tan
Askdsusggggn So
Sanaa adasan naacds
AQQLSOS LON Ao sOMAHzaaK
Sdangdandgdrisugdacds
FSINAANNNAR AANA AN a
SANE deHennoadwsodan
qos ssqadodeqddgce
Sadao sNssassres
209m +BDOWNAHHMONDOd
Sdddyunddscaddvgcadd
SESFARNAA RANA
SSSVQegngeynndanaacen
qecddtnnddntsdndsddd
{RM ONS Ms
Sachada
STIMAAN
QHIZQIOLHNOLNOOMaNCDO
DETOOEANKRKNOR ATMA D IOS
FOBDAIHGANNSHAMMAKRAN
AamznHonaro
eeddecee desdadddeoss
51.9 52.9 3.6 22.3 W.3 35.6 20.8 22.3
Mean value
32.9 33.3 203. 11.9 8.2 22.6 15.0
Mean value
TABLE 36
TABLE 33
Claremont Beach, Virginia
Measurements of Sample of Glycymeris subovata (Say), 1824,
ris subovata (Say), 182),
Natural Well, North Carolina
Measurements of Sample of G:
Lt Wi ll c/2
Ht
Specimen
T2-B
c/2
ll
Ht lt
Specimen
QYtQINVAENVeQONzoONOw+S
Stes sad gsegssgeqs
Addn
QSVTAHSHVVOSSCOM@HHH =O
Sesasa sense nsagagg©
SAL SNAIL YoagagdaenoHo
QISASrd aA gia ktagsoad
UN OAT ANSON ENN SE AIE= 501 NSO (1.
qdesddmiqcgiaddsGuag na
2 ASA= FS a
BWROAWHQVOWNOHOAHYODNH
gauge dade seedadecees
sag FQADASKO
i
NANT
PIAMOKNAASNOHE OE AnH
WARD OHOHSOSO DOS OND
QASRARRSAAARAASAS
SCIEN OCH EIS SIRI
Ameen oe edgsadds
QLANYHIOAR MOH SO QOstd ye
AANA STASIS SS shaq Gas
SAedsendeycdsoseynyy
Qdasssadasssevsgaga
Ada mooQHosgndeeronned
Arad asadshcteddd Add dad
PeQLwenddwernnonmonszyo
qe jose GIstasddsqgds ¥
AAI ANONAdd Ad HaaYROOR+
Aiddadndddddddcodcdodadd
QAV USA IIIITII AINA
BNasseeaddans seasa
AAA
WENLOBdQWQONLeHOdddds
daagenssondadsdorreadga
ARAAARRAAAANAS Aan
ICI OCR |
eam dee ae
27.9 28.7 2.0 9.3 6.9 20.0 13.0
Mean value
26.5 1.5 969 702 76h 10.9
24.8
Mean value
TABLE 37
Measurements of Sample of Glycymeris subovata (Say), 1824,
TABLE 34
s
z
z
&
do
g
a
z
E
2
Colerain Beach, N. C.
B
Boykins, Va.
Lumberton, North Carolina
feasurements of Sample of Glycymeris subovata (Say), 1824,
wi
T)-B
To-T,
li
Localities
B
Specimen
T2-T, T2-B
c/2
ll
Lt
Ht
Specimen
Sore Hzeyvoenoneyzwaegny
SS 08° easeadaeesaacda
ddeyeored+anonnoccon
ANSAIANMENAN AAA MRA
QANTIBHONNQIMTOONOAHO
geagqul Aq atdqdcddsgAgadd
WU dd ssh oHnezeanowen
SANS8°s9 ssa 5se9% 45915
T9SVPONdIedh we HeooI AM
ROGNGernvadGr assis ged
PzOrroCMH ON HHDDoHaAMNA
NAddd add AAS dG
Sa eT inet °
dod 4285
NAA ANd
BHANHOSDNHQD a
FABIAN Std MMe
AA ewer dere eddee
BAe ee AeA Qe eee
SAA AAAke ewe
Adin tase rg IVosos545e
AADAYVAQVSANHHOBHO+IN0
AVADHL QOH ADROANDNTIHOM
Gusruugsshgtrsendens
Sqvanndonnoconnaamnoor
Sqr grsger ava qedqsqars
NAdddd ddd dN dda
OrmwsrszoomoneconzooOnNnTON
SATE NEA ES NCSIN ESN RI EAR LS Gas
RAVAVISRANAASSAARRAA
ANNZHSEDOOdANND SOLE BAO
eeaeneeeneged added
8.9 2.9 15.2
6.7 2.9
1.4
18.3
Mean value 3.8
25.8 1.9 Fak 6.6 17.1 10.8
24.6
Mean value
51
Birp
ACEA?
Mip-ATLANTIC TERTIARY ARC
TABLE 38
Acme, North Carolina
Measurements of Sample of Glycymeris pectinata (Gmelin), 1792,
TT, 12-3
c/2
Ht Lt wi
Specimen
OBO Td ANE HAQD FONOMHHO
SttPARARSIRAAKESGRAAS
DQBOMDMADMAWHOMHDORMOOA
BrGSrtechkrisddigrdisid
Fea tN ee SONA ral lo cee nn ae esta
TAMA AMMAN ONTO ttt
WARE ODEMNOOWANONANDMOS
SIAN EASA DHSSSSKHSIRG
AOE QDEOHHEOMOHOOQOOD
ASSCSSCGHOSOdAAAAAAAAS
NGAI ALO VIANeSAsS
adddgsa2dedsqs4sagag
WHOCOZDMOENTHOODOHNOD
asdidgd°desags4qdiag
ANMNAHOEDARO Hoe anro
Goseueemadddedaedaes
12.3 12.5 1.2 4.5 3.7 7.6 5.2
Mean value
PLATES
Figure
a
PALAKONTOGRAPHICA AMERICANA (V, 34)
EXPLANATION OF PLATE 1
Nucula proxima Say
Yorktown, Va., Yorktown fm. a. Exterior of mature left valve. Fine radial
striae, which are present beneath the outer layer of Ca CO; are not visible in the
photograph; 3.6, U. N. C., No. 3511. b. Interior of same shows fine dentic-
ulations on inner margin, small beaks, and highly arched dental series; 3.6.
2 Nuculanan(Saccella)) vacuta (Compa) esccccencceec-eecnseaioestessereteersneceeteeeestece cet aceaneeenes
10, 12.
James City, N. C., Croatan sand. a. Exterior of mature right valve shows the
regularly spaced concentric ornament of even weight; « 3.3. U. N. C., No. 3512.
b. Interior of same. The resilifer small; teeth tend to be chevron-shaped; beaks
tinys) <3)
Wioldiqe dliaiearsie (Sia )y scvesssectsescctucccessesrees reece cee een cae ten ee ce aaceecrc trea onan nce eee Uae
Worrel Mill Pond, N. C., Yorktown fm. Exterior of adult left valve. The orna-
ment consists of growth lines only; beaks inclined posteriorly; % 3.0. U. N. C,,
No. 3513. 4. Black Rock, N. C., Yorktown fm. Interior of broken right valve of
adult. Resilifer large; teeth chevron-shaped; x 1.6. U. N. C., No. 3515.
Anadara (Anadara) lienosa (Say)
Town Creek, N. C., Waccamaw fm. a. Exterior of right valve ot adult. Costae
of the umbonal ridge are more abundantly divided than elsewhere on the valve;
x“ 0.9. U. N. C., No. 3523. b. Interior of same. The terracing of the ligamental
area by the chevron grooves is well developed. Fine longitudinal striae, which
are related to growth lines, are observable. Teeth change from convergent at the
anterior and posterior margins to slightly divergent toward the center of dental
series; xX 0.9.
Simtancas centenaria: \((Siaty)s c..sesscssevsstevscctessaverectece foc estacs seeteectae seen meta er cnemeotecerecneae ca ttereeeretoats
Kings Mill Wharf, Va. Yorktown fm. a. Exterior of left valve of adult shows
irregular weight and spacing of ribs and riblets. Ventral sag is not accompanied
with a byssal gape; x 1.0. U. N. C., No. 3517. b. Interior of same. Teeth hollowed
by weathering, both muscle scars elevated; ligamental area amphidetic and
vertically striated; x 1.0.
“ircopsis (Aircopsis)) <adamst \(OD alll) ceccrsccsnestscesceetesessestens ceserseereccevenevanee-coorsencatvecrese ences
Acme, N. C., Waccamaw fm. 7. Exterior of adult left valve shows beaded nature
of ribs; & 4.3. U. N. C., No. 3515. 8. Interior of an adult left valve shows large
teeth, edentulous gap at center, and triangular pit for the ligament directly under
the hinge line. Ligamental area vertically striated; muscle scars elevated; & 4.0.
UNC; Now 3516.
Anadara (Anadara)canolimerdusis, \(Dialllll)) cessrstcereterssettessestessess tovesceccesnseeccaneeeetenineee eters
Claremont, Va., Yorktown fm. a. Exterior of weathered adult right valve. Costae
flattened, nodose, slightly grooved ventrally. x 1.0. U. N. C., No. 3524. b. Interior
of same. Lateral members of the dental series distinctly chevron-shaped, extreme
lateral members lose this characteristic with the result that members near the
center, and outward to the extremities, are divergent and at the lateral ex-
tremes are convergent. Posterior muscle scar and pallial line irregular due to
leaching; X 1.0.
Anadara (Anadara) ‘callicestos a \(Wiallll)i ccccsessveteccasshenscessees scvset-sessaeevsssenecstsuvesearitneencrstetatensere
Natural Well, N. C., Duplin fm. a. Exterior of left valve of young. Umbos
prominent; costae, especially the posterior ones, tend to be grooved and are
abundantly nodose; 3.0. U. N. C., No. 3521. b. Interior of same. Teeth at this
stage of growth large in relation to the size of the valve; ligamental area small;
crenulations extend far dorsally; > 3.0. 11. a. Left valve of adult. Costae grooved
two to four times in this specimen and are nodose. * 1.4. U. N. C., No. 3522.
b. Interior of same. Teeth not so large in relation to the size of the valve as in
the younger form; ligamental area wider, the crenulations extend far dorsally;
x 154:
21
21
26
25
28
27
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 1
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 2
Mip-ATLANntic TERTIARY ARCACEA: BIRD
EXPLANATION OF PLATE 2
Figure Page
Neg. alanine (Calera), Gdkncrtlagioas: (USSU) — Greposcnceceertocenco-nconsrececeuconccececomprecermocnecccere 27
Silverdale, N. C., ‘Trent fm.” 1. Interior of adult right valve. Beaks slightly pro-
sogyre and subcentrally located; teeth small and nearly obsolete at the center
of hinge line; x 1.7. U. N. C., No. 3520. 2. Exterior of adult right valve shows
distinct umbonal ridge and widely spaced ribs which are more elevated and
rounded than those of the left valve and less nodose posteriorly; 2.0. U. N.C.,
No. 3519. 3. Left valve of young shows slightly flattened and nodose ribs with
the nodes extending far posteriorly; 2.0. U. N. C., No. 3518.
br ACCTAR (CHORE), TAEDA. (SERA) ssccesceco-cencccespooccceneoco x.coc conan Ioocaceee pa pecc Rec peace OED COREE 30
Town Creek, N. C., Waccamaw fm. a. Exterior of left valve of adult. Costae
slightly more elevated, less flattened than the right valve; & 1.3. U. N. C., No.
3527. b. Right valve of same specimen shows slight discrepancy in ornament
between the left and right valves, which in some specimens is developed to a
greater degree than in the one illustrated. Larger left valve is seen to slightly
overlap the right valve ventrally; x 1.3. c. Cardinal view of same specimen.
Beaks are slightly prosogyre; X 1.3.
5, Os 2tbiaelore \(elivaehia) ene Degas (SESAY ccccecocerecece soda neccon nen oboe Renee Gon orc) por SoceECLOCECEO Tn eae 30
Natural Well, N. C., Duplin marl. a. Adult right valve of Conrad’s “Arca
improcera.” Ribs on the illustrated specimen of this relatively elongate form
are flattened and nodose anteriorly; x 2.0. U. N. C., No. 3525. b. Interior of
same. Ligament low. Posterior muscle scar typical and not distinctive from
typical “4d. buccula”’ forms; 2.0. 6. Atlantic Beach near Morehead City, N. C.,
Recent. Left valve shows same shape and ornamentation as fossil representatives
of the species; X 1.1. U. N. C., No. 3529.
Ho ATO CGTAGIT RD) RATES TORO, (SENAY Pepsceccertonncern erecpecec ry peepee porec caso se epececeeey SILO EENOECOD 30
Natural Well, N. C., Duplin marl. a. Left valve of the ‘drea buccula’” form of
Conrad. Form has a slightly less elongate, more convex shape, and a higher
ligamental area than that of the “Arca improcera’’ form. The differences
between the two types are not consistent and gradation between them is complete;
xX 2.2. U. N. C., Cat. No. 3526. b. Interior of same; XX 2.2. Ligamental area
wide on this specimen, posterior muscle scar atypically small and round.
wi DUTT Ohiey Vice CTI” (OD) AC READS CO). Cobeaeeec tere eececeecr Ooecec hee Coe eee eee re RoaECe OPED eras eee SeeCnc 32
Longs, S. C., Waccamaw fm. a. Interior of mature right valve. Specimen displays
the off-set anterior dental series, and opisthodetic ligamental area characteristic
of the genus; & 1.4. U. N. C,, No. 3531. b. Exterior of same. Costae flattened
and slightly grooved; x 1.4.
G) RUCGITRE \ANRECCTAD)) VRCTISHOPIE. (CSENAY. Teecespscecee cer ascecnc cee oce ace COCOScEEE A HhacceeCpccee Chor pecpeoRtN=cccas 30
James City, N. C., Croatan sand. a. Exterior of mature left valve. Specimens
from the vicinity of Conrad’s type “drca subsinuata,” of which the illustrated
specimen is one, are large but are not otherwise distinct from conspecific 4.
(4.) transversa; X 1.2. U. N. C., No. 3528. b. Interior of same; X 1.2.
Ohare Viorica (Eortra) i t7zC1l en (Says) acesessseszsssccseescaeueos<dscestes« atesicscccsacascocasesstervusecare cies tr euaureeerteeeeeee 34
Yorktown, Va., Yorktown fm. a. Exterior of mature right valve. Riblets (primary
ribs of MacNeil, 1938) poorly developed and costae divided only along the
umbonal ridge. Beaks situated well anteriorly; « 1.4. U. N. C., No. 3532.
b. Cardinal view of same specimen. Beaks nearly orthogyre; ligamental area
strongly striated vertically; >» 1.4. 11. Morgarts Beach, Va., Yorktown fm.
Interior of strongly alate left valve of mature specimen; 1.7. U. N. C., No. 3533.
ND, TB, iach (UROTICD) TACTIC’ (COGN) copsceeeececrocerecncnsnere cereee pose BEE Poe cos ace eeReRO SCC EE eSceO 35
Natural Well, N. C., Duplin marl. a. Exterior of mature right valve. Posterior
margin more strongly emarginate than the average in this specimen. Primary
ribs slightly better developed than in N. (E.) incile; & 1.5. U. N. C., No. 3535
b. Interior of same. Anterior teeth in specimens of this species rarely become
L-shaped to parallel the hinge line while this condition is common in N. (E.)
incile; 1.5. 13. Right valve of young individual. Beaks not so anterior as in
N. (E.) incile, ribs more distinctly grooved posteriorly, and ribs delicately and
abundantly lirate; « 2.1. U. N. C., No. 3534.
or
or
50
Figure
NF
nN
PALAEONTOGRAPHICA AMERICANA (V, 34)
EXPLANATION OF PLATE 3
Page
Noetia: ((Bortia) eilimnatlasa (Conrad)! geecccsccertcc ete eee ee
James City, N. C., Croatan sand. a. Exterior of right valve of typical adult. Beaks
anterior in relation to valve length. Valve is elongate with a median ventral
sag. Nearly all costae divided; x 1.0. U. N. C., No. 3537. b. Interior of right
valve of same specimen. Anterior teeth tend to be L-shaped; x 1.0. c. Cardinal
view of same specimen. Beaks opisthogyre and subcentrally located with respect
to shell length. At James City numerous specimens were collected with both
valves intact, indicating a biocenose assemblage. 1.0.
Anadara (Gunearca)ect Any (Cs) nico g rua i(Say))ossecese ester eee eee
Walkers Bluff, N. C., Waccamaw fm. a. Interior of fragmented left valve at
slightly oblique angle. Ligamental area lacks the chevron-shaped grooves of
Anadara, s.s.; X 2.1. U. N. C., No. 3530. b. Exterior of same. Ribs coarsely
nodose and no riblets present in the interspaces; % 2.1.
Nioetiae (Eoztia) mp onderosal \(S ay) menccsorsrccocercces terrae cette cence rece ee ee
Atlantic Beach near Morehead City, N. C., Recent. a. Interior of adult right
valve. Beaks opisthogyre and situated slightly posterior to the middle of the
hinge line. In adult specimens of this species the posterior muscle scar tends
to be conspicuously elevated; %& 1.1. U. N. C., No. 3541. b. Exterior of same.
Posterior margin sharply truncated so that the valves have a subtriangular
shape; umbos high, costae tend to be flattened; primary ribs poorly developed;
bean lanes
Noetia ((Eontia) = platyrirae \(iWyalll)\ Were cccrercesecee-coreeceseeseetteocteseseetaet eee ae ore ae srenateenetaerereceeerereere
Town Creek, N. C., Waccamaw fm. Left valve of an unusually elongate form
of the species; 1.1. U. N. C., No. 3540. 5. Walkers Bluff, N. C., Waccamaw
fm. Right valve of a mature, quadrate form. Specimens similar to this were also
collected from Town Creek indicating that quadrate forms are not so restricted
in their distribution as supposed by MacNeil, who reported it only at Walkers
Blufé (1938. p. 21/5) SS 1051. Ne (Cs Nox3539!
Noetia ((Bontia). (carolinensis) i Gonmadieessmcserrnctscteerstotecete tenes eaee eee tree eee eee
Black Rock, N. C., Yorktown fm. a. Exterior of mature left valve. Beaks sub-
central, costate divided across nearly the entire shell; delicate lirae ornament
ribs and interspaces. Typically, as in the figured specimen, there is no ventral
sag; & 1.0. U. N. C,, No. 3536. b. Interior of same. Subcentral beaks slightly
opisthogyre, anterior teeth do not tend to be L-shaped. Small bryozoan colony
situated under the anterior muscle scar; 1.0.
Noctia (Eontia) platyura (Dall) sachs sdetectcecovaniteeseset
Town Creek, N. C., Waccamaw fm. a typical adult of
this variable species. The anterior teeth tend to be L-shaped; no ventral sag;
1.0. U. N. C., No. 3538. b. Exterior of same. Valve relatively high in relation to
length and does not flare posteriorly as it does in N. (E.) limula. Costae
divided over most of the shell; in adults the posterior costae are commonly
grooved more than once. N. (E.) /imula shows a tendency for multiplicity of pos-
terior ribs but to a lesser degree; 1.0.
31
37
36
35
36
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 3
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 4
Figure
Ue
4.
Glycymeris americana (Defrance)
Glycymeris subovata (Say) .......
Mip-ATLANTIC TERTIARY ARCACEA: BiRD
EXPLANATION OF PLATE 4
Old Dock, N. C., Waccamaw fm. a. Exterior of large left valve. Ornament of
rounded costae with distinct striations separated by narrow, rounded inter-
spaces which are also striated; &% 1.0. U. N. C. No. 3547. b. Interior of same.
Teeth strongly chevron-shaped; ligamental area has vague suggestions of chevron
ornament and vertical ridges; % 1.0.
Giicymierismap ant lism (Commas percent trccntersercecereere eter erence recente eceecescentenrcnate
Plum Point, Md., Calvert fm. a. Interior of weathered adult right valve. Small
beaks orthogyre, teeth tend to be large, but are small in relation to size of
the valve when compared to G. /entiformis. Ligamental area marked with vague
chevron ornament; in this large form suggestions of vertical striations can be seen
.to be related to the distribution of nubbins of resorbed central dentition; x 0.9.
b. Exterior of same. All observed specimens of this species were badly
weathered. Ornament consists of costae of low relief with faint suggestions of
striations and narrow interspaces. Posterior-dorsal margin shows the character-
istic oblique truncation; x 0.9. U. N. C., No. 3544.
Kings Mill Wharf, Va. Yorktown fm. a. Right valve of large individual.
Ligamental area marked with distinct chevron-shaped ornament; 1.0. U. N. C.,
No. 3550. b. Exterior of same. Costae in this specimen sharply crested, a
feature which many specimens possess irrespective of stratigraphic age. No
striae on the costae; X 1.0.
Gila cya rt sip Cel Uspml (Coma Ci) terraces: cacnaheseecievecesctrnrys se ccaseces Costes ese cona sree es reat oon nee A eee
Plum Point, Md., Calvert fm. a. Interior of right valve of young individual.
Dental series not complete even in young forms. * 1.2. b. Exterior of same.
Costae equal in weight; shell is suborbicular with the dorsal, anterior, and
posterior margin all tending to be straight in young forms and the convexity
(7.e., width) is low; X 1.2. U. N. C., No. 3545.
39
41
39
Kr
PALAKONTOGRAPHICA AMERICANA (V, 34)
EXPLANATION OF PLATE 5
Figure Page
1, 2. Glycymeris anteparilis, Kellum) ...........:.2:.ssssscecsssssesescecssssenecerntesnerscenvenenonarseosvessssnsesassnanscese 38
Silverdale, N. C., “Trent fm.” a. Exterior of left valve of an adult. Dark lines
only slightly elevated and are separated by wide areas which have many faint
striations; & 0.8. U. N. C., No. 3542. b. Interior of same. Ligamental area
ornamented with strong chevron-shaped grooves, central teeth perpendicular
to the hinge while the lateral members are parallel to the hinge. x 0.8. 2. Ex-
terior of weathered left valve. Weathered, impressed lines, which serve as the
interareas between the ribs, are in the position of the dark lines of the specimen
Ine figeeday xe LOU ING C2 No 35437
3. Glycymeris americana (Defrance) .....-.....s:.cccssssssscsesssessssensersnsncesteseesausesssseeneretsensranarecsaserenes 40
Old Dock, N. C., Waccamaw fm. a. Exterior of posteriorly produced left valve;
“x 1.2. U. N. C., Cat. No. 3548. b. Interior of same. Posterior dental series
produced in conjunction with the rest of the shell; >< 1.2.
4. Glycymeris lentiformis (Conrad) ........ Besos sche atens sab eso ea is ROA TAL SU eae ER EES SOTERt Ts tae ERE 40
Boykins, Va., Yorktown fm. a. Exterior of left valve. Ornament consists of
rounded costae with distinct striations separated by fine impressed interareas;
x 0.9. U. N. C., No. 3546. b. Interior of same. Teeth large in relation to the size
of this adult valve. Lateral teeth tend to parallel the hinge line and are
widely spaced; X 0.9.
5. Glycymeris subovata (Say) csesesecccesccssssccssscessseccsereererecesecesnerenerersssenssenessscensncansucecassccesscecnsesees 41
Morgarts Beach, Va., Yorktown fm. a. Exterior of young left valve. Costae of
this specimen flattened as are the wide interspaces between the costae. Some
of the ribs show a tendency to be grooved; some specimens of the species
develop secondary ribs of irregular weight and distribution on the primary
ribs. The widely spaced, flattened ribs are characteristic of Dall’s (1898, p. 611).
G. subovata tuomeyi. Gradation with more typical specimens of G. subovata
does not seem to be complete and specimens of this type may be valid subspecies;
% 2.0. U. N. C., No. 3552. b. Interior of the same. Dental series complete in
young forms; in adults the series often broken by an edentulous gap under the
beaks; xX 2.0.
6. Glycymeris americana (Deframce) .ccccccccccscesees cesses tes eeessssssseeesensseneenieesensecctecteeniectennss 40
Old Dock, N. C., Waccamaw fm. a. Exterior of young left valve. Costae unequal
in weight across the valve; costae rounded and striated as in the adult;
x 1.9. U. N. C., No. 3549. b. Interior of same. Ligamental area narrow and
dental series is continuous under the beaks; 1.9.
7, 8. Glycymeris pectinata (Gmelin) ;
Acme, N. C., Waccamaw fm. Exterior of large adult left valve. Costae coarser
and less numerous than in G. subovata of the same size; valves have a
consistent trigonal shape; 1.9. U. N. C., No. 3554. 8. Interior of adult left
valve shows strongly arched dental series, distinct chevron-shaped grooves on the
ligamental area, and trigonal shape; 1.9. WeeNan Ca eNo 35555
9, 10. Glycymeris subovata (Say)
Williamston, N. C., Yorktown fm. A portion of the ligament is still preserved
on this posteriorly produced left valve. Dall (1898, p. 611) referred to forms with
this shape as G. subovata plagia. These produced forms show all degree of
gradation with more symmetrical individuals at Williamston, where the
produced form is most common; X 1.3. U. N. C., No. 3553. 10. Kings Mill Wharf,
Va., Yorktown fm. a. Right valve of young form. Costae rounded and closely
spaced; & 1.5. U. N. C., No. 3551. b. Interior of same. Dental series complete ;
ligamental area displays well-formed chevron-shaped grooves; X 1.5.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 5
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 6
Bs
BB ay
Figure
1.
2-6.
2.
Mip-ATLANTIC TERTIARY ARGAGEA: BIRD
EXPLANATION OF PLATE 6
Anadara (Anadara) propatula (Conrad) :
Rices Pit, Hampton, Va., Yorktown fm. U. S. N a. Exterior
of left valve of adult. Shell expanded posteriorly, ribs grooved down the middle
and slightly nodose; 1.0. b. Interior of same. This specimen has a low liga-
mental area marked by the terraced chevrons typical of the genus. Crenulations
coarse, typical of Anadara; 1.0.
Each figured species is a Recent representative. The structure in each case is
crossed-lamellar consisting of elongate, alternate light and dark bands (see
basal portion of fig. 4 and fig. 5) and chevron-shaped or cross-hatched inter-
sections of rhombohedra or prisms of CaCO;. The sections of Arca (fig. 3)
Anadara (fig. 5) and Noetia (fig. 6) display tiny needles generally oriented
vertically. The composition of the needles is undetermined; they are not soluble
in dilute solutions of HCl and are isotropic. They are not the needle-like calcite
structures at the intersection of calcite rhombs reported by Dechasequx (in
Piveteau, 1952, pp. 252, 253).
With the exception of drca (fig. 3), the figured specimens show a convex
upward inflection of layers of CaCO. and an organic substance (probably con-
chiolin, represented by dark lines) in the position of costae.
Lunarca cf. L. ovalis (Bruguiére)
Transverse section, left valve. The section shows intense, flat-topped folding of
laminae under costa and down buckled zones of intercoastal areas. Basal portion
of shell does not show folding and interior of shell is not ridged in the position of
intercoastal areas; 25.
Arca cf. A. umbonata Lamarck.
Transverse section of right valve. No flexing of laminar exists in shell. Central
portion of section shows strong lamellae (inclined to right) crossed by weaker
lamellae to produce a cross-hatched effect. 25.
‘elipgrlanan (COL@ROCO)) TRG RTE (SEND). cereceesciceccevesteesecre beeen enero eeecct encod ee eeeae ence
Transverse section, right valve. Folding of laminae extends to inner surface of
valve and produces ridges in intercoastal areas in interior of shell. Laminae are
bowed gently upward under costae, which increase in width upward; 25.
DGGE, (clade), GREAT HOROL, (ONESP)) ceces-ceeccensscco/eec dooce ottnosceto-o: pevcocnereceseeeicesemorteeereren
Transverse section, left valve. Laminae gently flexed downward under intercoastal
areas and upward under costa; X25.
INQ AURORE). PODEORDOE (SESA). cheondecccscec chee bsp teres poco ee eect ees pono
a. Transverse section near center of left valve. Ribs here are cut nearly per-
pendicular to their elongation. Needles appear as discontinuous, short rods. Fold-
ing of laminae is well formed and extends about two-thirds of the way from
top to base of shell under intercoastal areas. Laminae folded abruptly upward at
margins of costa and gently convex upward under the costa. Laminae in upper
portion of figure 6b correspond to laminae under the costa but cut obliquely; x25.
b. The section is near posterior margin of shell and obliquely cuts a rib. Alternat-
ing light and dark bands are crossed by inclined laminae of an obliquely cut rib
in the upper portion of section. At this position the needles are seen as nearly
continuous, elongate lines. The ostracum at base of section is mildly rumpled,
as it may be in other species examined; 25.
31
30
INDEX
Note: The left hand bold faced figures refer to the plates. ‘The right hand
light figures refer to the pages.
A cae - 2223 drymanos,
Fu he Calvert Cliffs Glycymeris 42
Abarbaule: T 20 ae Calvert County, Dubar, J. R., and
ee 31. 41. 42 Maryland : ls. 3 Solliday, J. R. 9
aherrans ae Calvert formation Tey 48h; Duplin County,
Glycymeris 41 ; 10, 16, 26 North Carolina O25"
Acar 29 95 campechensis, 27, 29
Noe ; é manatees 32 Duplin marl aan me a
, : ‘ape Cod, , 28, 40, 41
North Carolina 49 a et Massachusetts 21, 31 duplinensis,
mcrtamiNaculana see? Cape Fear arch 11 Glycymeris 42
(Saccella) Tots, cece Heats rver g
adamsi, Arcopsis Cape Hatteras, E
eer North Carolina 25, 42
(Arcopsis) e25 ’ .
aequicostata, Arca 31 Cara 23, 26, Echinochama 17
Africa 33 ; : 27 Ecphora 16
altilis, carolinensis, Anadara Edgecomb County,
Ptychosalpinx 16 (Anadara) 1 27, North Carolina 8
Alum Bluff group 21 : , 28, 29. Eocene % ©,
americana, Noetia (Eontia) 34. 35 33
Glycymeris 4,5 16, P 36, 37, 48 F
17, 39, 40, 41, 49, 50 centenaria, Arca 26
Anadara is als), Scarce 1 16, 26 filosa limula, Noetia
2ie§22 23), 26.027, 28, 29g nae beds 9 (Eontia) 35
30,31,/42,93,47 Chesapeake Bay ty 8 trigintinaria, Noetia
anteparilis, : Chesapeake group is 5, poor) 35
lycymeris th : ’ Florida
as 38, 39, 49 Choptank formation 7. 8, Phi ry, Bi, Sil, Sah 36° 38
antiquata, Arca 27 10, 11, 26, 40 41, 42
Arca, 5.s. Onl oi Chowan River 8, 9, floridana, Anadara
23, 26 16, 17, 36 (Anadara) 28
Arca 5, 21, Claremont, lienosa, Anadara
26, 31, 32, 38 Virginia es (Anadara) 28
Arcaina 5 i , 50 Foraminifera 136
Arcopsis Clark, W. B., and Fossularea , 25
(Arcopsis) 22, 25, Miller, B. L. 7, 8 France 33
26, 32, 33 ; 9
Argina 23h aime aclcWASLOnensis
39 yariabae an a G
Arginella 31, 33 Devan monte :
Arginopsis sijjasy Colerain, ‘North C116, 21 26. 28, 29, 41, 43
Arkell, W. J. 6 Carolina 17, 40. Georein Nae at ecg
Atlantic Beach, 50 Glycymeris D5 at
North Carolina 31, 32, | Conrad, T. A. 6, 27, Yate a) ob OR oy ae
’ ’ 5 i i 5 5 H 9,
37. 47. 48 x0 GHle Zl
» 47, CookeiG@. W. 8 40, 41, 42, 48, 49, 50, 51
Atlantic Coastal , glycymeris. Arca 38
Plain 6. 26 Copeland, C. W. 9, 11 glycymeris,
: Cossmann, M. 25; 32 Granoarca 22, 26,
B costata, Lunarca 32 27
Courtland, grapta, drymanos,
Barbarca 23 Virginia 9. 17, Glycymeris 42
Barbatia Op ORS 26,42 Gray, J. E. 5, 6,
26, 27, 29, 32 Craven County, ? 23, 27, 32
Black Rock, North Carolina 8, 9, Greenville County,
North Carolina 48 10, 11 Virginia
Blackwater River 8 Cretaceous 9525; Gulf of Mexico 11, 20,
Bladen County, 26 21, 28, 38
North Carolina 9 Croatan, North H
Béggild, O. B. 6 Carolina 9, 36 f
Boykins, Virginia 9, 40, Croatan sand oa ble Halifax County,
42, 49, 50 17, 36, 40 North Carolina 8
Brazil 25 Cucullaea Hawaiarca 23
Breviarca 26 Cucullaearca 22 Hawaii 23
brevidesma, Arca 30 Cucullaria 22 Hampton, Virginia 30
Bronn, H. G. 29 Cunearca 22. 28. Haywood Landing,
Brown, P. M. Ue tk 31 North Carolina ee
10, 11 Heath, H. 6, 22;
buccula, Arca 2 30 D 23, 27, 32
Hertford County,
Cc Dall, W. H. Gia 9 Maryland By 29
: 21, 22, 23, 25, 27, 28, 29, Hopkinson, J. 32
callicestosa, Anadara 31, 32, 35, 40, 41 Horry County, South
(Anadara) We2ve 28 Diluvarea 26, 27 Carolina
60
idonea, Anadara
(Anadara) 29
improcera, Arca 25730
incile, Noetia
(Eontia) 7) AG
34, 35, 36, 47
incongrua, Anadara
(Cunearca) 3,631
Arca 31
interposita,
Scapularca 33
Isle of Wight County,
Virginia 8
J
James City County,
Virginia _° 8
James City
formation 9
James City, North
Carolina eh alee
36, 40, 47, 48
James River 8, 29,
40, 42
Jurassic 6, 25
K
Keen, M. A. 6
Kellum, L. B. Up OU
Kings Mill Wharf,
Virginia Sig"
42, 47, 50
L
laevis, Yoldia yo Bul
Larkina PAS PAL
Leda 21
lentiformis,
Glycymeris SmeliGs
39, 40, 49
leptalea, Leda 21
lienosa, Anadara
(Anadara) 1 28
limatula, Yoldia 21
Limopsis 5
limopsis, Acar 25
limula, Noetia
(Eontia) 5 =} if.
34, 36, 37, 48
lineolata, Arca 31
Linne, C. 5
Lirosoma 16
Lister, M. 32
Longs, South
Carolina 32
Lowman, S. W. 11
lumberensis, Noetia
(Eontia) . 37
Lumberton,
North Carolina 9, 11,
17, 37, 40, 41, 50
21, 23,
31, 32, 33
Lunarca
M
MacNeil, F. S. a,
By BP BBL ohh Shy 36, 37
Magnolia,
North Carolina 9
INDEX
magnoliana, Anadara
Corrine 28
Mansfield, CG. @ th
Wi OL Te aly, AY
mansfieldi, Noetia
(Eontia) 35
Marylang Ul, tek
10, 35, 38, 40, 4i, re
Maury, C. ap ; Sil
McLean, J. D. 6, 16
Meherrin River g 7
Miocene
LOE GH 25.034: a5 38.
40, 41
Morehead City,
North Carolina 31
Morgarts Beach,
Virginia 9, 42
Mount Gould, North
Carolina 17, 40
Murfreesboro, North
Carolina 8, 9,
16, 42
“Murfreesboro
stage” 8
N
Nansemond County,
Virginia 8
Nansemond River 8, 28
Natural Well 295 lel
17, 27, 28, 30. 35, 40, 41,
42, 47, 49, 50
Neuse River San
New Bern,
North Carolina eh
11
Newell, N. D. 6
Nicaraugua 42
Nicol, D. 6, 38,
41
nigeriensis,
Protonoetia 33
Noetia 9, 16,
pay Pal, PRE SRL Be eby
36, 37, 38, 47, 48
North Carolina iy, fh,
OO 25 22829)
Bil Bb 36, 37, 40, 41, 42,
47, 48, 49, 50, 51
Nottoway River 8
Nova Scotia 20
Nucula 5, 19,
20
Nuculana 21
nucleus, Nucula 20
ie)
Obliquarca 22
Old Dock, North
Carolina Oh ailré
31, 49
Old Sparta, North
Carolina 8, 9
Oligocene
Olson, C. E., and
Miller, R. L. 7
Olsson, A. A. 8
ovalis, Arca 32
Lunarca 2,632
6]
Pp
Pacific Coast 6, 33
palmerae, Noetia
(Eontia) 37
parilis,
Glycymeris 4 7,
16, 39, 40, 48
Parker, R. H. 20 aie
28
pectinata,
Glycymeris Sale
42,51
Pectunculina 5
Pectunculus 5, 41
Perry, L. M. 31
pexata, Arca 32
Pitt County, North
Carolina 8
plagia subovata,
Glyecymeris 41
Plagiarea 22
platyura, Noetia
(Eontia) 3} if,
34, 36, 37, 48
Pliocene Oh alae
17, 34, 37, 41
Pleistocene 9, 21,
BPA, Bi, Ske
plicatura, Arca 31
Plum Point,
Maryland 7, 40,
48
ponderosa, Arca 34
Noetia
(Eontia) nse Oe
34, 37, 38, 48
Polynema 22
polychoa,
Leda 21
proteracuta, Leda 21
ratty re 6
Prince George County,
Virginia 7
Prionodonta 21
propatula, Anadara
(Anadara) 6 29,
30
Protonoetia 3 33
protracta, Arca 28
proxima, Nucula 1 19.
20
Ptychosalpinx 16
Pungo River
formation 7
Q
quadrata variabilis,
Noetia (Eontia) 30
quadricostata,
Ecphora : 16
quinquerugatus,
Pectunculus 41
R
Rappahannock
River al
Rasia 23, 26,
27
Recent i} Ath
G21 23 B28 328 aS,
34, 37, 41
reeveana,
Cucullaearca 22
Reinhart, P. W. 63.22:
935125. 27. 32505
reticulata, Acar 25
reversa, Arca 33
Richards, H. G. by
Roanoke River 8
Robeson County,
North Carolina 9
Robulus it
Rogers, D. J., and
Tanimoto, T. T. Ry Af
11, 18, 22
Rost, H. 63.26;
27
Ss
Sabol, J. W. 16
St. Marys County,
Maryland 8
St. Marys
formation Milo, 335
11, 26, 29, 40
St. Marys River 8
sealaris, Anadara
(Cunearca) Sil
scalarina, Anadara
(Cunearca) 31
Scapharca 22, 26,
27
Scapularca Banoo,
34
scapulina,
Seapularca 35
secticostata, Anadara
(Anadara) 28
Shattuck, G. B. Ul 33
Sheldon, P. G. 6, 28.
Sheldonella 34
Shepard, F. P., and
Moore, D. G. 11
Sherborn, C. D., and
Woodward, B. B. 32
Silverdale, North
Carolina ; Zi aNf0}s
27, 39, 49
silverdalensis, Anadara
(Anadara) Uo
27
Simpson, G. G. 18
Sokal, R. D., and
Michener, C. D. Yip ats}
Somerset County,
Maryland iy 8}
South Carolina ONS2i
41
Southampton County,
North Carolina
Southampton County,
Virginia 9,
17
species arcoid 23
Anadara
(Anadara) 46, 47
Foraminifera 20
gastropod and
pelecypod 12; 13,
14, 15, 16
INDEX
Glycymeris 43, 48,
49, 50, 51
Noetia (Eontia) 34, 38,
47, 48
Statistical analysis
bivariate
analysis 5G;
18
correlation
coefficient (jz
cluster (hy able
1G iene en22
information
theory 6
match
coefficient Teall
22
multivariate
analysis SiO;
18
prime node aly alte}
22
Q-technique Ghats
18
R-technique 6, 18
regression 6, 31,
35, 39, 40, 41, 43, 44
t-test 68;
19
Ux value 11, 18,
19, 22
Stevenson, L. W. 26
Stevenson, W. 6
Striarca 16, 26,
32) 33
subovata,
Glycymeris C Pelle
41, 42, 50
subsinuata,
Arca Gill
sulcosum, Lirosoma 16
Suffolk,
Virginia alk, Ash
40
sullanensis,
Arginopsis 33
Sumpter County,
South Carolina 9
Sussex County,
Virginia 8
LL
Talbot County,
Maryland li
Tampa formation ra
Tar River 8
tarponensis, Anadara
(Anadara) 27
Tertiary Gaal
10, 32
Texas 20) 31
41
tillensis, Noetia
(Eontia) 36
Town Creek, North
Carolina 9, 36,
47, 48
transversa, Anadara
(Anadara) ASHE
30, 31, 47
62
Trent formation Piles
; atl
triangularis,
Noetia 33
Triassic 25
trigintinaria, Noetia
(Eontia) 2 34,
; 35, 36, 47
tuomeyi subovata,
Glycymeris 5 42
U
umbonata, Arca 6
Vv
variabilis, Noetia
(Eontia) Bly OH
Virginia by
8, 9, 11, 27, 28, 29, 30, 38.
40, 41, 42, 47, 49, 50
Ww
Waccamaw
formation yr ilal,
17, 28, 36, 40, 41
Waccamaw River 9
Walkers Bluff, North
Carolina Orsi
36, 40, 47, 48
waltonensis,
Glycymeris 41
Wayne County,
North Carolina 8
West Indies PAR CP,
White River 27
Williamston, North
Carolina 11, 40,
41
Wilmington, North
Carolina 11
Wilson, D. by eZ
Wilson, D., and
Brown, P. M. 7
wilsoni callicestosa,
Anadara
(Anadara) 28
Woodring, W. P. 27
Worrels Mill, North
Carolina 9, 50
ny.
Yoldia 21
York County,
Virginia 8
York River 8
Yorktown
formation Sieg?
11, 16, 17, 26, 27, 34, 41
Yorktown,
Virginia ~* Ge)
o- Conia
a Peas
7 a
7 .-
Toe
iC
"hes
PROXCN Amn INOS: 1402145) pe 400 Rp pin 19) 185 centecscceceeceocesseseectvesesrerersnsettsoreasessm OO
Trinidad Globigerinidae, Ordovician Enopleura, Tasma-
nian Ordovican cephalopods and Tennessee Ordovician
ostracods, and conularid bibliography.
XXXV. (Nos. 146-154). 386 pp., 31 pls. ........
G. D. Harris memorial, camerinid and Georgia Paleocene
Foraminifera, South America Paleozoics, Australian Or-
dovician cephalopods, California Pleistocene Eulimidae,
Volutidae, Cardiidae, and Devonian ostracods from
Iowa.
SXONOKGW Ne (INO Gsg 155-11 60) SmetU ZOD yet S IND SeMlersanrencteresrnececesecercatconeneencsnreneraees . 16.00
Globotruncana in Colombia, Eocene fish, Canadian-Chaz-
yan fossils, foraminiferal studies,
BNOXONC WIN on INOS sO a G4) m4 8 Open SMD Shierececrarcstencncencconeextheccsaennecasoseencarens 16.00
Antillean Cretaceous Rudists, Canal Zone Foraminifera,
Stromatoporoidea
SEXNMVENEE (Noss 165-176) ) 44-7) pps 53) DS. ocean ase a cen cnec cep ceenceccacscccancecaces 16.00
Venezuela geology, Oligocene Lepidocyclina, Miocene ostra-
cods, and Mississippian of Kentucky, turritellid from
Venezuela, larger forams, new mollusks, geology of Car-
riacou, Pennsylvanian plants.
SNONONCIENC (INO Bs 2/7/11 83)) 48D 55905 01D Sag tear een cecseeeterenateenareneenrereescoeetenestces 16.00
Panama Caribbean mollusks, Venezuelan Tertiary forma-
tions and forams, Trinidad Cretaceous forams, Ameri-
can-European species, Puerto Rico forams.
NU (INOse 1 S4) e996 PDs) Ly Dletecscsssssesvenscnseacecersxonscasonensscstoseassassasensspssonen 16.00
Type and Figured Specimens P.R.I.
HG (OG, DERE a Sei fos ol kh See 16.00
Australian Carpoid Echinoderms, Yap forams, Shell Bluff,
Ga. forams. Newcomb mollusks, Wisconsin mollusk
faunas, Camerina, Va. forams, Corry Sandstone.
RATAN Ten IN 93) Sm S a DP iS DBs i encecauccsessconttenahnnccossuscncnssasvesccssctrasonssceps 16.00
Venezuela Cenozoic gastropods.
XLIII. (Nos. 194-198). 427 pp., 39 pls. -.....----ssesseseeeres
Ordovician stromatoporoids, Indo-Pacific cam
sissippian forams, Cuban rudists.
UAVS, (Osta TEER) GXCET johny CEI) Ss eee se ree cers 16.00
Puerto Rican, Antarctic, New Zealand forams, Lepidocy-
clina, Eumalacostraca.
inids, Mis-
XLV. (No. 204). 564 pp., 63 pls. ...csersersccscrscsssnscncenessssnccnssnssnecnssnsessesees 16.00
Venezuela Cenozoic pelecypods
DONA (ONG Asean DS BI) eyes 7AN) 90) is ere 16.00
Large Foraminifera, Texas Cretaceous crustacean, Ant-
arctic Devonian terebratuloid, Osgood and Paleocene
Foraminifera, Recent molluscan types.
XLVII. (Nos. 212-217). 574 pp., 83 pls. ...sccscsecsscsersersessersssessessssssersssssasseesnes 16.00
Eocene and Devonian Foraminifera, Venezuelan fossil
scaphopods and polychaetes, Alaskan Jurassic ammonites,
Neogene mollusks.
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13, -P
AMERICANA
Volume V
No. 35
1965
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PALAEONTOGRAPHICA AMERICANA
(Founded 1917)
VOL. V
NO. 35
DIMYARIAN PELECYPODS OF THE MISSISSIPPIAN
MARSHALL SANDSTONE OF MICHIGAN
EGBerT G. DRiscoLt
Wayne State University
August 10, 1965
PALEONTOLOGICAL RESEARCH INSTITUTION
ItHaca, New York, U.S. A.
Library of Congress Catalog Card Number: GS 65-135
MUS, GOMP. ZOOL
LIBRARY
AUG 81 1965
FARVARD
UNIVERSITY
Printed in United States of America
Norton Printing Company
CONTENTS
Page
Abstract : Ratovenecceterdaness 67
Introduction 67
Acknowledgments 67
Systematic paleontology ............ 6 Oy
Family Ctenodontidae ........... oxo (57
Genus Ctenodonta Salter 67
C. stella (Winchell) 268
Genus Palaeoneilo Hall. ......... 4. 7h)
P. sulcatina (Conrad). ......... 0)
P. concentrica (Winchell) Al
iP truncata: Elalllll cites... 9/3
Family Nuculidae. ......... ert
Genus Nuculopsis Girty . weueraeves 74
PNRM 1h) REO TDI (SHEW;ENNS)) ) teesecesecescesseeseccrarsceres tress ceeecnsocesecretestecetzsusntvaccessaxcetsens 75
N. sectoralis (Winchell) S76
Family Nuculanidae ................. . 78
Genus Polidevcia Chernyshev 78
P. pandoraeformis (Stevens) 79
Family Solenomorphidae ......... 81
Genus Prothyris Meek ......... _ Sil
P. rectidorsalis (Winchell)
Genus Sanguinolites McCoy
S. ? herricki, sp. nov. ....... 6
S. unioniformis Winchell . 84
Genus Sphenotus Hall 85
S. obliquus (Meek) 85
Genus Solenomorpha Cockerell 87
S. scalpriformis (Winchell) 87
SWAG 9-5 O GILT CCSD OM TLOMIausactrss cnerewnrersceneecesencn cee omepn oneness suscaresstaes vonnenreceercentwnscareces 88
Genus Palaeosolen Hall 89
P. quadrangularis (Winchell) 89
P. frontisocurvus, sp. nov. ... 90
Family Grammysiidae .......... 91
Genus Grammysia de Verneuil ... 91
G. omaliana omaliana (de Koninck) 91
G. omaliana hydet, subsp. MOV. ...cc.ecceceecereeren 98
Family Parallelodontidae 98
Genus Parallelodon Meek and Worthen 98
Subgenus Cosmetodon Branson _........ 98
P. (C.) sp. aff. P. ovatus (Hall) 98
P. (C.) marshallensis (Winchell) 99
Family Myophoriidae 100
Genus Schizodus King in Murchison, de Verneuil 100
Seanrostratasanl OVVANC Dell) tesrer-ceresessceccsstessecseessese-ceecenesssceazeneceresnassnarnees ee LOW
S. 2 similis (Winchell) ....
S. sectoralis (Winchell)
S. triangularis (Herrick)
S. chlersi, sp. nov. ..
Family Astartidae
Genus Cypricardella Hall
C. 2 securis (Winchell)
Correlation
Age of the Marshal
References cited
Plates
sandstone
TABLES
1. Illustration of overlap of height/length ratios in species of Solen and
Palaeosolen 89
2. Comparison of mean height, mean length, and number of ribs per 0.5 cm.
(Se) OL Grammy stan Omaliamay =.) + c.-sccssecsesssseseeeresncnsterceses:
3. Geographic and stratigraphic distribution of pelecypods .....
4. Distribution of certain pelecypods in the Marshall formation of Michigan 107
DIMYARIAN PELECYPODS OF THE MISSISSIPPIAN
MARSHALL SANDSTONE OF MICHIGAN
EGBERT G. DrIscoLy
ABSTRACT
Twenty-five species belonging to the genera Ctenodonta, Cypri-
cardella, Grammysia, Nuculopsis, Palaeoncilo, Palacosolen, Paral-
lelodon, Polidevcia, Prothyris, Sanguinolites, Schizodus, Solenomor-
pha, and Sphenotus are described. Most species examined are from
the Mississippian Marshall sandstone of Michigan, but related
species from the Waverly group of Ohio and the Coldwater forma-
tion of Michigan are also discussed. The majority of species ex-
amined have been previously described, but not illustrated, by Alex-
ander Winchell. One new subspecies, Grammysia omaliana hydei,
and four new species, Palaeosolen frontisocurvus, Solenomorpha
dorsocurva, Schizodus ehlersi, and Sanguinolites ? herricki are pro-
posed.
Accessory muscle scars on species of Ctenodonta and Nuculopsis
are utilized to aid in the orientation of these protobranch mollusks.
The Marshall sandstone is correlated with formations of the
Waverly group between the base of the Black Hand member,
Cuyahoga formation, and the top of the Allensville member, Logan
formation, and is tentatively considered to be of Osagean age.
During Marshall time the Findlay arch is believed to have been,
at least in part, below sea level. Similar faunas in southcentral
Ohio and in the Michigan basin indicate that migration between these
two areas was possible during Marshall time.
INTRODUCTION
Between 1861 and 1871, Alexander Winchell published
a series of stratigraphic and paleontologic studies in which
the large majority of the species herein discussed were
named and described, but not illustrated. The absence of
illustrations and, in certain cases, the incompleteness of the
original descriptions have resulted in a poor understanding
or misunderstanding of many of Winchell’s species. It has
been found necessary to revise the systematic position of
many of the species here described. Winchell’s type material,
much of which is preserved in the Museum of Paleontology,
University of Michigan, has been available to the writer.
Abbreviations are used as follows: UMMP., University
of Michigan, Museum of Paleontology; OSU., Ohio State
University; USNM., United States National Museum;
BMNH., British Museum (Natural History); AMNH.,
American Museum of Natural History.
The measurements quoted from articles by Alexander
Winchell are in inches. The numbers in parentheses are
relative measurements, the greatest dimension being ex-
pressed as 100 and other measurements as percentage fig-
ures.
With the exception of the genera Prothyris, Polidevcia,
Schizodus, Ctenodonta, and Palaconcilo the supergeneric
classification employed by the writer is that used by Paul
(1941, pp. 317-319). Prothyris is here included in the
Solenomorphidae, and Polidevcia in the Nuculanidae,
Schizodus is placed in the family Myophoriidae, and
Ctlenodonta and Palaconcilo are assigned to the Ctenodon-
tidae (see Schenck, 1954).
ACKNOWLEDGMENTS
The writer is indebted to members of the staff of the
Museum of Paleontology, University of Michigan. G. M.
Ehlers, R. V. Kesling, and E. C. Stumm provided advice and
encouragement throughout the project. Dr. Ehlers’ broad
knowledge of the geology of Michigan and Dr. Stumm’s
preliminary work in the identification of Alexander Win-
chell’s type specimens were of particular value. Critical
reading of the manuscript by Dr. Kesling is gratefully
acknowledged.
For the loan of comparative material and assistance in
the location of various type specimens the writer acknowl-
edges the assistance of H. W. Ball, British Museum of
Natural History; Edward M. Brigham, Jr., Kingman
Museum of Natural History, Battle Creek, Michigan; G.
Arthur Cooper, United States National Museum: Henry
F. Donner, Dept. of Geology, Western Reserve University;
C. L. Forbes, Sedgewick Museum, Cambridge, England;
J. S. Jackson, National Museum of Ireland, Dublin: Erle
G. Kauffman, United States National Museum; Norman D.
Newell, American Museum of Natural History; John J.
Stevens, Dept. of Geology, Ohio State University; Donald
P. Squires, American Museum of Natural History; A. G.
Unklesbay, Dept. of Geology, University of Missouri.
Acknowledgement is made to Wayne State University
and to the Geology Department of Wayne State University
for payment of the cost of the engraving of the plates.
SYSTEMATIC PALEONTOLOGY
PHYLUM MOLLUSCA
CLASS PELECYPODA
ORDER PROTOBRANCHIA
FAMILY CTENODONTIDAE
Genus CTENODONTA Salter, 1851
Tellinomya Hall, 1847, p. 151, mon Agassiz, 1846, p. 363.
Ctenodonta Salter, 1851, pp. 63-64; 1859 pp. 34-35; Whidborne, 1896,
pp. 98-99; Ulrich, 1897, pp. 578-580; Hind, 1898, pp. 209-210.
Type specices—By subsequent designation (Salter, 1859,
pp. 34-35) Tellinomya nasuta Hall (=Ctenodonta logani
Salter) .
Remarks.—As pointed out by Schenck (1934, p. 18),
“There is no reason to place in the family [Nuculidae]
those forms that lack taxodont dentition and a chondro-
phore. Nor should the family include those forms that
possess a pallial sinus (20), or those genera whose repre-
sentatives have definite siphons... .”) “Vhis definitive
statement 1s important because it clarifies the limits of a
68 PALAEKONTOGRAPHICA AMERICANA (V, 35)
eroup with which members of the present genus are still
occasionally confused.
The validity of the names Ctenodonta Salter (1851, pp.
63-64) and Tellinomya Hall (1847, p. 151) has been dis-
cussed by Oehlert (1888, pp. 652-654), Whidborne (1896,
pp. 98-99) , Ulrich (1897, pp. 578-579) , Hind (1897, p. 177;
1898, p. 209), and Williams and Breger (1916, pp. 156-
159) among others.
In summary, the problem is as follows: in 1827 Brown
proposed the name Tellimya for a group of lamellibranch
shells other than those here being considered. Agassiz
(1846, p. 363) incorrectly considered it acceptable to
change the spelling of this name to Tellinomya thus cre-
ating a nomen vanum. Brown (1849, p. 225) continued to
use Tellimya. In 1847 Hall (p. 151), not realizing that
Tellinomya was preoccupied by an invalid name, proposed
that it be applied to the group of lamellibranchs here dis-
cussed. Salter (1851, p. 63) proposed the name Clenodonta
for this group of shells. Ctenodonta, being the first valid
name used for this genus, must be retained.
Ctenodonta logani Salter, the type species of Cteno-
donta, and Tellinomya nasuta Hall, the type species of
Tellinomya, were shown to be identical by Hall (1856, p.
391) and Salter (1859, p. 34). Salter recognized that
Tellinomya nasuta must be retained as the type species of
Ctenodonta because Ctenodonta logani, though previously
named by Salter (1851, p. 269), had not been described
and was, therefore, a nomen nudwm.
Williams and Breger (1916, p. 159) contended that “The
name Ctenodonta in the strict sense would be a synonym
of ‘Tellinomya, but in the expanded usage of Ctenodonta
adopted by Salter and other authors various heterogeneric
species were included. The first of these species described
and figured, Ctenodonta astartacformis Salter, is readily
separable from Tellinomya nasuta and its allies and is
capable of standing as a nucleus of a separate genus.” It is
beyond the scope of this paper to discuss the generic value
of these two groups characterized by Tellinomya nasuta
(=Ctenodonta logani) and Ctenodonta astartaeformis.
Should these two species belong to different genera, then C.
astartaeformis and related species must receive a new name,
because Tellinomya is preoccupied by an invalid name.
Concerning the relation of Ctenodonta to Palaeoneilo,
Hall (1885, p. xxvii) said “in general form and internal
characters this genus [Palaconeilo] very closely resembles
Tellinomya [=Ctenodonta] and it is probable that fur-
ther study will prove that the two are congeneric.”’
Conversely, Oehlert (1888, pp. 653-654) believed that
“Ctenodonta est principalement caractérisé, ainsi que nous
l'avons dit, par sa forme subrostrée, ses crochets saillants
et presque centraux, tandis que dans le genre Palaeoneilo,
les crochets sont reportés ver l’avant, le c6té anterieur est
moins largement arrondi et enfin il existe une depression
umbonomarginale sur le c6té posterieur.”
Beushausen (1895, p. 70) contended that Palaeoneilo is
a subgenus of Ctenodonta, stating: “Die Menge von For-
men, welche zu Ctenodonta gestellt werden muss, zerfallt
wiederum in einige deutlich unterscheidbare Hauptgrup-
pen oder Untergattungen, welch untereinander durch
Uebergange verknipft werden.
subgenus Ctenodonta s. str. from subgenus Palaconcilo
.” He distinguished his
emend. by the latter’s stronger and more posteriorly di-
rected sinus, truncated or sinuous posterior margin, and
concentric ribbing.
Ctenodonta and Palaconecilo are treated here as distinct
genera.
Anterior pedal
Dorso-median
retractors
Ventro—median
Anterior pedal
Posterior
Pprotractors
adductor
Anterior
adductor
Text-figure 1—Composite drawing of Ctenodonta stella (Win-
chell) from natural internal molds. Small nodes in umbonal region in-
dicate positions of accessory muscle scars. Scars indicating position of
attachment of dorsomedian, ventromedian, anterior pedal protractor,
and anterior pedal retractor muscles are present.
Ctenodonta stella (Winchell)
Plate 7, figures 1-18; text-figure 1
Nucula stella Winchell, 1862, p. 419.
Ctenodonta stella Winchell, 1865, p. 129.
Ctenodonta (Nucula) stella Herrick, 1888, vol. 3, p. 78.
Nuculopsis stella Paul, 1941, p. 34.
Original description.— (Winchell, 1862, p. 419).
Shell very small, elliptic-ovate, with subcentral beaks. Anterior
cardinal slope arched, posterior nearly straight; extremities rather
sharply rounded; ventral side semi-elliptic., Anterior hinge plate with
17 minute, acute teeth; posterior with 5, angulated in both cases to-
ward the beak. Beaks a little attenuated near the extremity, curved
inwards and backwards. Pallial line entire, connecting the muscular
scars, which are oval, and situated considerably above the middle
line of the shell. Shell thin, with delicate concentric striae.
Length °33 (100); height :24+ (73); thickness ‘14 (42); length of
MUISSISSIPPIAN DIMYARIAN PELEGYPODS: DRISCOLL 69
anterior end +20 (61); of posterior end ‘13 (39); distance from
beaks to line adjoining extremities -14 (42).
Localities —At every outcrop of the formation in the southern part
of the State. Also at the Grindstone Quarries, Pt. aux Barques.
This beautiful little shell has affinities with N. ventricosa, Hall
(lowa Rept. 716, pl. 29, fig. +) 1858, from the coal measures of
Iowa. It is easily mistaken for the young N. hubbardi, but is proved
distinct by its more rounded sides and fewer teeth, as well as by its
occurrence in a region of the State where the larger species is as yet
unknown.
Revised description.—The following description is based
on 44 specimens from the Marshall sandstone of Michigan.
Thirty-seven of these specimens have previously been de-
scribed by Alexander Winchell (1862, p. 419; 1865, p. 129).
Equivalved, small, subelliptical; dorsal, ventral, and
posterior margins gently and evenly rounded; anterior mar-
gin evenly rounded to subangular below mid-height of
valves; prosogyrous, beaks situated above hinge line ap-
proximately 1/3 of the length from anterior extremity,
curved inward and anteriorly; umbonal ridge inconspicu-
ous.
Shell thin, commonly smooth in umbonal region; weak
concentric striae present; near anterior and ventral borders
regular concentric ridges developed on some specimens.
When present these ridges disappear posteriorly and dorsal.
ly.
Pallial line entire, connecting anterior and posterior ad-
ductor muscle scars, the former being more prominent than
the latter (PI. 7, fig. 4). Numerous small muscle scars
present in the umbonal region (PI. 7, figs. 2, 17; text-
fig. 1). Most commonly preserved are the dorsomedian
and ventromedian muscle scars found slightly posterior to
beaks. Anterior to beaks a series of pedal retractor and _pro-
tractor scars, commonly four or five, extend from the um-
bonal region toward the anterior adductor scar.
Taxodont dentition, 5 to 8 teeth observed anterior to
beaks and 12 to 17 posterior to beaks (PI. 7, fig. 18).
Chevron shape of teeth commonly not preserved. Size of
teeth progressively larger toward extremities of valves, small
beneath beaks; chondrophore absent.
Remarks.—The short end of Ctenodonta stella is here
designated as anterior on the basis of the orientation of
small accessory muscle scars in the umbonal region and the
correspondence of these scars to muscles in certain living
protobranch mollusks (Driscoll, 1964, pp. 61-66) .
Heath (1937, pp. 10-14, pls. 1-10) described and figured
the musculature of certain living protobranch pelecypods.
He contended (p. 14) that the dorsomedian muscle and
the ventromedian muscle are a constant feature of proto-
branch mollusks. These muscles, the former of which ex-
tends, for the most part, into the pedal tissue, and the latter
into the ventral wall of the visceral mass, are consistently
attached to the shell near the central part of the animal in
the umbonal region. The scars found in the umbonal
region of Ctenodonta stella correspond well with the dor-
somedian and ventromedian muscles figured by Heath for
Acila divaricata (pl. 5, fig. 39) and Yoldia limatula (2)
(pl. 7, fig. 58; pl. 8, fig. 63; pl. 10, figs. 85, 86). In Nucula
nucleus (Linné) and Ennucula obliqua (Lamark) , as fig-
ured by Schenck (1934, pl. 5, figs. 1, la; pl. 3 fig. 4), it is
noteworthy that the dorsomedian muscle scar is elongate, a
character not present in Ctenodonta stella nor, as indicated
by Heath’s figures, in Yoldia limatula or Acila divaricata.
Nuculopsis houghtoni (Stevens) , which is discussed else-
where, does exhibit such an elongate scar in this position;
a scar here considered to be due to both the dorsomedian
and ventromedian muscles.
Odhner (oral communication to Schenck) suggested
(Schenck, 1934, p. 21) that the scar of the dorsomedian
muscle be called the median muscle scar and that of the
ventromedian muscle the central muscle scar. In the above
discussion the writer has preferred to follow Heath’s term-
inology.
Ctenodonta stella possesses a series of four or five small
muscle scars extending in a short arc from the umbonal
region toward the anterior adductor scar. This series of
scars corresponds well with the location of the anterior
pedal protractor and retractor muscles of Yoldia mon-
tereyensis (Heath, 1937, pl. 6, fig. 51), Yoldia inflata
(Heath's pl. 6, fig. 53), Yoldia limatula (?) (Heath’s pl.
8, fig. 58), and others. No similar series of muscle scars is
found on the posterior side of the beak in such forms. The
series of punctiform scars in Nucula nucleus and Ennucula
obliqua, which are illustrated by Schenck, are only gen-
erally comparable, being located more distant from, and
with a different angular relation to, the hinge line. It is
noteworthy, however, that they are found anterior to the
beaks.
The mechanics of foot protrusion in the living proto-
branch lamellibranchs illustrated by Heath requires that
the anterior pedal protractor muscles be attached to each
valve anterior to the anterior pedal retractors. In my
opinion, a similar arrangement of muscles existed in
Ctenodonta stella. This conclusion is further supported by
the fact that those muscles nearest the umbo in the pro-
tractor-retractor series of Ctenodonta stella are somewhat
larger and more pronounced. Heath (his pl. 9, fig. 75) fig-
ured Yoldia sapotilla, illustrating the anterior pedal re-
tractor muscles as notably larger in diameter than the
anterior pedal protractors, a situation considered to be
analogous with that which existed in Ctenodonta stella.
70 P ALAEONTOGRAPHICA
Ctenodonta stella possesses a single muscle scar immedi-
ately posterior to the anterior pedal protractor-retractor
series the function of which is unknown. Possibly this scar
is a member of the pedal protractor-retractor series but
located slightly posteroventral to the principal muscle are.
Acila divaricata, as figured by Heath (1937, pl. 5, fig. 39),
illustrates anterior pedal protractor and retractor muscles
which do not form a simple arc.
Paul (1941, p. 34) included the present species in the
genus Nuculopsis Girty (1911, pp. 133-134) . The writer has
examined 35 specimens of Nuculopsis girtyt Schenck (1934,
p. 30) (=Nuculopsis ventricosa Hall), type species of
Nuculopsis, from the Pennsylvanian of ‘Texas (UMMP.
Nos. 16964, 22456, and 28766) among which (No. 28766)
are certain well-preserved interiors. As was concluded by
Schenck (1934, p. 29), “That a chrondrophore is present
cannot be doubted.’ The present species, possessing no
chondrophore, cannot be included in the genus Nuculop-
Sis.
Types and occurrence.—At the time of his original de-
scription (1862, p. 419), Winchell had in his possession 33
specimens of Ctenodonta stella from the Marshall sand-
stone. A left valve from Battle Creek, Calhoun County,
Michigan, (UMMP. No. 37673) is here designated as the
lectotype. The other 32 specimens which Winchell de-
scribed in 1862 are paralectotypes. Of these, 20 (UMMP.
Nos. 37674-37693) are from Battle Creek, Michigan; the
other 12 (UMMP. Nos. 26900, 37694-37704) are from Mar-
shall, Calhoun County, Michigan. Four additional speci-
mens from the Marshall sandstone at the Napoleon rail-
road cut, Jackson County, Michigan, (UMMP. Nos. 27772,
37711-37713) were added to Winchell’s collection prior
to his 1865 publication. Seven hitherto undescribed speci-
mens (UMMP. Nos. 37705-37710) are hypotypes. UMMP.
No. 37705 is from the Marshall sandstone in the SE. 4%, Sec.
7, T.6N., R. 12 W., Kent County, Michigan. UMMP. No.
37706, a block bearing two specimens, and UMMP. Nos.
37707-37710 are from the Marshall sandstone at Marshall,
Calhoun County, Michigan.
In summary, Ctenodonta stella is known to occur only
in the Marshall sandstone but is common and widespread
within that formation. According to Winchell it is found
at every locality in the southern part of Michigan.
Genus PALAEONEILO Hall, 1870
Palacancilo Hall and Whitfield, 1869, p. 6; 1870, p. 6.
Palaconeilo Hall, 1885, pp. xxvii-xxvili; Oehlert, 1888, pp. 653-654;
Beushausen, 1895, pp. 65-70; Whidborne, 1896, pp. 98-99; Mce-
Alester, 1962, pp. 16, 17.
AMERICANA (V, 35)
Type species.—By subsequent designation (Hall, 1885,
p. xxvil) Nuculites constricta Conrad.
Remarks.—Comments concerning the relationship of
Palaconeilo and Ctenodonta are included under the dis-
cussion of the latter genus.
Some confusion has resulted because Hall (1870, p. 6)
used the spelling Palacaneilo rather than Palaconeilo in his
original definition of the genus. This conflict was ulti-
mately resolved in favor of Palaconeilo by the Interna-
tional Commission on Zoological Nomenclature (Bull.,
vol. 4, 1950, pp. 399-400; Opinion 215, 1954). Not all
workers (e.g., Sinclair, 1951, pp. 411-412 and McAlester,
1962, p. 16) are in agreement with the commission.
Palaeoneilo sulcatina (Conrad)
Plate 9, figures 1-12
Nuculites sulcatina Conrad, 1842, p. 250, pl. 15, fig. 10.
Nucula hubbardi Winchell, 1862, pp. 417-418.
Nucula hubbardi var. prolata Winchell, 1862, p. 418.
Ctenodonta hubbardi Winchell, 1865, pp. 128-129.
Original description.— (Conrad, 1842, p. 250).
Triangular; posterior side cuneiform; valves with concentric striae
and a few remote furrows; posterior dorsal margin subrectilinear,
very oblique, extremity acutely rounded; basal margin slightly emar-
ginate near the anterior extremity, which is acutely rounded; beaks
distant from the anterior extremity, prominent.
Revised description —Conrad’s type material is lost. The
following description is based on topotype material and
specimens known to have been utilized by Winchell in his
1862 and 1865 publications.
Equivalved, inequilateral, ovate-triangular, moderately
tumid valves. Anterior and posterior portions of dorsal
margin subrectilinear, forming an angle of from 120° to
140° below the beaks. Valves high in umbonal region,
steeply sloping to posterior margin, which is sharply round-
ed. Ventral margin evenly and gently curved and broadly
rounded into anterior margin.
Prosogyrous, beaks situated about one-third of total shell
length from anterior end, curved inward above hinge line.
Pallial line entire, strongly marked on most specimens,
somewhat sinuous posteriorly. Anterior adductor-muscle
scar oval, immediately below hinge line in anterior ex-
tremity of valve. Posterior scar somewhat smaller and weak-
er, immediately below posterior extremity of hinge line.
No accessory scars observed.
Taxodont dentition extending anteriorly and posteriorly
along hinge line; change of direction but no break in teeth
below beaks (PI. 9, figs. 4, 6). Dentition not reaching pos-
terior extremity of dorsal margin. Thus, dorsal margin of
valve continues subrectilinearly for a short distance beyond
posterior limit of dentition betore curving into abruptly
rounded posterior margin. Teeth chevron-shaped, convex
MIsSISSIPPIAN DIMYARIAN
toward beak, increasing in size toward hinge extremities.
Number of teeth variable, maximum of 38 found on pos-
terior part of hinge, maximum of I1 counted anteriorly.
Convex surface of teeth marked by parallel striations ex-
tending from base of each tooth to tooth extremity (PI. 9,
fig. 5). Number of striations varying with size of tooth,
commonly more plentiful, 10-14, on larger anterior teeth.
Concave side of teeth smooth.
External ornamentation of irregular concentric striations
and grooves, in many specimens varying on a single valve
from coarse grooves to faint striae (PI. 9, fig. 9). External
ornamentation generally reflected faintly, or not at all, in-
ternally.
Remarks.—Leda_ barrisi White and Whitfield (1862, p.
298) was indicated as synonymous with Palaconeilo sul-
catina by Weller (1898, p. 408). The writer has examined
White and Whitfield’s type specimens from Burlington,
Iowa, (UMMP. No. 2106) and believes that P. sulcatina
may be distinguished by its greater height relative to
length, by its more rostrate posterior margin, by the more
pronounced angle between the anterior and posterior parts
of the hinge line, and by its commonly larger size.
Hyde (1953, p. 293) pointed out that “Both Hall and
Weller have made P. hubbardi a synonym of P. sulcatina.
But apparently the P. sulcatina of Hall and the P. hub-
bardi of Winchell are not synonymous.”” He suggested that
Palaconeilo hubbardi of Winchell was synonymous with
P. sulcatina as defined by Conrad, and that P. sulcatina as
discussed by Hall (1885, pp. 347-348) was, therefore, dis-
tinct. The writer is in complete agreement with Hyde's
conclusions. Hyde also stated (p. 293): “It should be added
that I have seen specimens from Marshall, Mich., of the
form figured and described by Hall as P. sulcatina.” It is
true that forms identical with those described by Hall as
P. sulcatina occur in the Marshall sandstone. They are
described here as Palaconeilo concentrica (Winchell) .
Palaeoneilo sulcatina (Conrad) is clearly distinct from
P. concentrica (Winchell). P. sulcatina is higher at the
beaks, the beaks are more pronounced, the valves are less
tumid, the posterior margin is more pointed, the concentric
grooving is irregular, no ribbing is present, the angle be-
tween the anterior and posterior parts of the dorsal margin
is commonly sharper, and the taxodont dentition does
not extend so far posteriorly.
Nucula hubbardi var. prolata is here designated as
synonymous with P. sulcatina (Conrad). Winchell (1862,
p. 418) regarded it as a variety because it “. is very
ventricose, and more elongate anteriorly, with a ereater
number of teeth.” The writer has examined the single re-
PELECY PODS: DRISCOLI 71
maining poorly preserved specimen which is known to have
been considered a syntype of Nucula hubbardi var. prolata.
This specimen does not show the characters attributed to
it by Winchell. Furthermore, the number of teeth is a poor
character for specific differentiation in taxodont shells.
Palaeoneilo sulcatina is the most common invertebrate
fossil in the Marshall sandstone, with the possible exception
of Ctenodonta stella. Specimens are found at nearly every
fossiliferous locality of the formation, often in such pro-
fusion that the extraction of one specimen involves the
destruction of several others.
Types and occurrence.—Conrad’s type material of Nucu-
lites sulcatina is lost. The writer here designates as neo-
type a natural internal mold of a right valve, UMMP, No.
43870, from the Marshall sandstone at Battle Creek, Michi-
gan. Though it would be desirable to choose a neotype
from topotype material, none of the specimens available
to the writer from Moscow, Michigan, are as well pre-
served as the Battle Creek specimen. Hypotypes here fig-
ured are UMMP, No. 43871 from Battle Creek, No. 43872
from Moscow, No. 43873 from Waverly Quarry (one mile
northeast of Holland), and No. 43877 from Jackson
County, Michigan.
Some of the material in Winchell’s possession prior to
his 1862 description of Nucula hubbardi is still preserved.
UMMP, No. 26890, four specimens from Battle Creek, and
UMMP, No. 26901, six specimens from Marshall, must be
considered hypotypes of Palaconeilo sulcatina. UMMP, No.
26897, the only specimen still extant that was referred to
Nucula hubbardi var. prolata by Winchell, must also be
regarded as a hypotype.
Further, 16 blocks, UMMP, No. 27767, bearing speci-
mens of P. sulcatina from the railroad cut at Napoleon,
Jackson County, Michigan, must be considered hypotypes,
inasmuch as they were in the possession of Alexander Win-
chell prior to his discusesion of the species in 1865 (pp. 128-
129) .
Palaeoneilo concentrica (Winchell)
Plate 9, figures 13-29
Cardinia concentrica Winchell, 1862, pp. 413-414.
Sanguinolites concentrica Winchell, 1865, p. 128.
Palaconcilo sulcatina Hall, 1885, pp. 347-348, pl. 50, figs. 42-46;
Herrick, 1888, vol. 4, p. 44, pl. 4, fig. 17; 1889, pl. 2, fig. 17; 1895,
pl. 16, fig. 17; Hyde, 1953, pp. 293-295, non pl. 40, fig. 26. Non P.
sulcatina (Conrad).
Palaconeilo concentrica var. Herrick, 1888, vol. 3, pl. 7, fig. 37.
Palaconeilo ellipticus Herrick, 1888, vol. 3, pp. 80-81, pl. 9, figs. 13, 15.
Palaconeilo ellipticus var. plicatella Herrick, 1888, vol. 3, p. 81, pl. 4,
fig. 12, upper figure.
Palaconeilo ellipticus var. elegantula Herrick, 1888, vol. 3, p. 81.
Palaconcilo ellipticus var. allorismaformis Herrick, 1888, vol. 3, p.
81, pl. 4, fig. 12, lower figure.
Sanguinolites concentricus Miller, 1889, p. 510; Weller, 1898, p. 538.
? Palaconeilo concentrica Girty, 1928, pp. 120-121, pl. 23, figs. 12-18.
oie) PALAKONTOGRAPHICA
Original description.— (Winchell, 1862, pp. 415-414).
Shell of medium size ventricose, transversely elliptic, with sub-
equal extremities and marked ventral’ enrolment. Beaks appressed,
incurved, rising little above the hinge, distant one-fourth the shell-
length from the anterior end; umbo and middle of the shell flattened
antero-posteriorly; antumbonal ridge inflected towards the hinge,
forming above a lunuliform area; dorsal and ventral borders sub-
parallel in the adult shell; posterior end obtusely, or at length
truncately rounded; anterior end paraboloid. Hinge line straight and
rather extended posteriorly. A broad shallow inconspicuous sinus
extends from the posterior ventral margin towards the beak. Ex-
ternal surface marked, towards the beak, with remote, equidistant,
raised, concentric ribs and intervening flat belts; towards margin
the ribs gradually become sharp ridges, and the intervening belts
deep furrows—these characters being especially strong at the anterior
end; whole surface marked by faint incremental lines. Greatest con-
vexity of shell considerably below the middle.
1Winchell (1865, p. 128) says “In the original description of this
species, ‘ventral’ in the second line, should be changed to ‘vertical’.”
Length 1°30 (100); height +55 (42); convexity of left valve °24
(18); whole number of furrows on exterior 14.
Localities Hillsdale county at Jonesville, and S. E.
Sec. 33, Adams. ;
Differs from C. complanata in its greater relative transverse di-
mension and in its vertical enrollment. It may yet prove to be a
Grammysia.
Revised description.—The following description is based
on the lectotype and 15 hypotypes discussed below.
Shell equivalved, inequilateral, subtumid, closed all
around, length slightly less than twice the height. Ventral
and dorsal borders subparallel, closing somewhat pos-
teriorly. Dorsal margin subrectilinear, abruptly rounded
posteriorly into subtruncate posterior margin. Ventral
border curved, rounded upward posteriorly at angle of
about 120° to about 130°. Anterior margin evenly rounded.
Prosogyrous, umbos moderately gibbous, beaks situated
above hinge line, approximately one-fourth to one-fifth of
shell length from anterior extremity of valves. Lunule and
escutcheon absent, but incurved beaks may produce a
yy S. W. MA,
lunulelike area anteriorly.
Broad shallow sinus commonly present on postumbonal
slope, extending posteriorly to subtruncate margin.
Pallial line entire, strongly impressed, muscle scars not
observed. External ornamentation not reflected internally.
Taxodont dentition of numerous slightly chevron-shaped
teeth anterior and posterior to umbonal region (PI. 9, fig.
23). Teeth convex toward umbos. Posteriorly, dentition
extends along almost the entire dorsal margin, teeth being
perpendicular to the margin and larger posteriorly. An-
teriorly, teeth slanted so as to be nearly parallel to dorsal
margin posterior to beaks. Maximum number of teeth
counted anteriorly 8, posteriorly 27.
External ornamentation of distinct, well separated, sharp,
nonbifurcating, concentric ridges and fine concentric striae,
the latter weak and commonly not well preserved (PI. 9,
figs. 25, 27). Between ridges valve surface is typically either
flat or gently concave outward, Ridges evenly developed
over entire surface of valve.
AMERICANA (V, 35)
Remarks.—Although the number of teeth in observed
specimens has been mentioned above, this character, being
dependent on size and preservation, is not considered to
be of specific significance.
It is noteworthy that in a number of the specimens ex-
amined (UMMP. Nos. 43874 and 43875) the early growth
stages of the incurved beak lie immediately above the
hinge line. When the outer shell is removed to expose a
natural mold of the hinge line, this incurved portion of the
beak can be mistaken for a cartilage pit (PI. 9, figs. 21, 23).
Some confusion has arisen between those forms here con-
sidered as Palaconeilo concentrica (Winchell) and those
included under Palaconeilo sulcatina (Conrad) . Discussion
of the distinguishing characteristics of the two species is
included under remarks concerning the latter.
Herrick (1888, vol. 3, pp. 81-82) first recognized the
probable synonymy of Cardinia concentrica Winchell and
the group of shells which he called Palaconeilo ellipticus.
He rightly contended that the sole distinction between his
specimens and those assigned to Cardinia concentrica by
Winchell was that the taxodont hinge of Wincheli’s speci-
mens was not exposed. An examination of Winchell’s col-
lections confirms this observation. Therefore, despite the
fact that Winchell did not recognize the character of the
hinge line, his specific designation must be retained. Hyde
(1953, p. 293) suggested that the name for this group of
shells should be Palaeoneilo elliptica Herrick. Although
Hyde (p. 293) stated: “It should be added that I have seen
specimens from Marshall, Mich., of the form figured and
described by Hall as P. sulcatina,” he apparently did not
realize that this species had previously been described by
Winchell as Cardinia concentrica.
Unfortunately, Winchell’s original description not only
lacks a discussion of the hinge character but also contains
certain inaccuracies. The only specimen known to have
been in Winchell’s possession at the time of his definition
of Cardinia concentrica, UMMP, No. 37334, is here figured
on Plate 9, figures 13-15. This specimen is much distorted
by compression, a fact apparently not recognized by Win-
chell. Perhaps this accounts for his statement (1862, p. 414)
“Greatest convexity of shell considerably below the mid-
dle.” The greatest convexity of the valves is in the umbonal
region, except in the distorted specimen examined by Win-
chell. :
Girty (1928, p. 121) suggested that “If one may form an
opinion from Hall's figures alone [of Palaconeilo sulcatina,
1885, pl. 50, figs. 42-46], without examining a series of
specimens, he has included more than one species under
P. sulcatina. .’ This may be true, but certain of Hall's
MUSSISSIPPIAN DIMYARIAN
figures, as was recognized by Girty, appear conspecific with
Palaconeilo concentrica, and until more detailed study is
possible the writer chooses to retain them as a group.
The specimens of Palaeoneilo concentrica which Girty
described (1928, pp. 120-121, pl. 23, figs. 12-18) from the
Pocono sandstone of Pennsylvania have not been examined
by the writer. Girty emphasized that his shells have been
considerably deformed by pressure, a fact which may ac-
count for what appears from his figures to be a more pro-
nounced sulcus ventral to the umbonal ridge than that
found in typical specimens of Palaeconeilo concentrica.
Other characters, ¢.g., the depressed beaks, general shape,
and surface ornamentation, agree well with specimens of
P. concentrica examined by the writer.
Types and occurrence.—A single specimen, which was in
Winchell’s possession at the time of his 1862 (pp. 413-414)
publication, is still preserved. This specimen, UMMP, No.
37334 from Jonesville, Hillsdale County, Michigan, is
here designated the lectotype. Nine specimens from Alan's
and Germain’s quarries, Hillsdale County, Michigan,
(UMMP, Nos. 26886, 27756, 37330, 45061-43066) must be
considered hypotypes because they were described by Win-
chell (1865, p. 128) as Sanguinolites concentrica.
The writer further figured as hypotypes UMMP, Nos.
35427 and 35427A from Hillsdale, Hillsdale County, Michi-
gan. The locality of hypotype, UMMP, No. 43876, is prob-
ably near Battle Creek, Michigan, but is not known with
certainty.
In Michigan Palaconeilo concentrica (Winchell) _ is
known to occur in the Marshall sandstone of Hillsdale
County, at Jonesville, Alan’s and Germain’s quarries,
Mosherville, and Hillsdale. In Ohio it has been reported
from the Waverly group at Newark, and the Cuyahoga
formation of Licking County. In Pennsylvania a_prob-
able occurrence of P. concentrica is found 500 to 700 feet
below the top of the Pocono sandstone, near Saxon, Rid-
dlesburg, Marklesburg, and in Huntington County.
Palaeoneilo truncata Hall
Plate 10, figures 1-15
Palaeoneilo truncata Hall, 1885, p. 347, pl. 50, figs. 40, 41; Weller,
1899; pp. 32, 33; Pl. 4, fig. 21; Branson ef al., 1938, Pt. 2, p. 36, pl.
25, fig. 28; Hyde, 1953, pp. 296-298, pl. 40, figs. 28-32.
2? Sanguinolites marshallensis ? Herrick, 1888, vol. 3, p. 67, pl. 5, fig.
11; pl. 7, fig. 10. Non Sanguinolites marshallensis Winchell, 1862,
p. 415; 1871, p. 256 [=Parallelodon (Cosmetodon) marshallensis |.
Palaeoneilo ? marshallensis Herrick, 1888, vol. 4, pl. 4, fig. 18; 1889,
pl. 2, fig. 18.
Palaconeilo (2) marshallensis Herrick, 1893, pl. 16, fig. 18, possibly
also pl. 21, fig. 11. ;
Description.—The following description is based on six
specimens collected from glacial drift at Kalamazoo, Michi-
gan. ‘These specimens, because of lithologic similarity, are
~I
PELEGYPODS: DRISCOLI
believed to have originated in the Coldwater formation.
Equivalved, inequilateral, length approximately twice
the height. Dorsal margin slightly arcuate, broadly rounded
into evenly curved anterior margin. Ventral margin vari-
able, nearly straight, slightly convex or, especially in older
shells, slightly concave. Posterior margin truncate, straight
or slightly sinuous, abruptly rounded into dorsal margin
at angle of approximately 65° to approximately 70°,
sharply curved into ventral margin at angle of about 135°.
Valves moderately gibbous, greatest convexity in um-
bonal region. Broad sinus extending from truncate posterior
margin, most pronounced posteriorly, becoming shallower
toward umbo, and absent at the umbo; apparently a
mature or old age character.
Pallial line entire, truncate posteriorly. Anterior ad-
ductor-muscle scar strongly marked immediately below
anterior extremity of dentition (PI. 10, fig. 5). Posterior
adductor more weakly impressed below posterior ex-
tremity of dentition (PI. 10, figs. 5, 4). Small elongate
accessory scar present immediately dorsal and posterior to
anterior adductor scar (PI. 10, fig. 5).
Dentition taxodont, extending along nearly all of dorsal
margin (Pl. 10, figs. 2, 15). Teeth chevron-shaped, con-
vex toward umbo, larger anteriorly. In umbonal region
and immediately anterior to umbo teeth straight rather
than chevron-shaped. Maximum number of teeth counted
anteriorly 9, maximum number counted posteriorly 36.
Exterior ornamentation unknown from Coldwater shells.
Saidmitom bel (Elydes 395355 \:29])) ame
striae and regularly spaced, slightly imbricating corruga-
fine concentric
tions... . ’ on specimens from the Waverly group.
Remarks.—Vhe writer has examined the specimen of
Palaconeilo truncata figured by Hall (1885, pl. 50, fig. 41).
As recognized by Hyde (1953, p. 296)
AMNH, No. 6546/1, is not so well preserved as Hall in-
dicated (see Pl. 10, fig. 1 of present paper). Hall (1885,
pl. 50, fig. 40) figured one other specimen of P. truncata,
this specimen,
but this specimen has not been located.
Due to the poor preservation of Hall's specimen, and
the fact that specimens which the writer has examined from
the Coldwater formation (?) are all natural internal molds,
it is not possible to determine with certainty whether the
two are specifically identical. On the other hand, no
characters are present which allow them to be clearly dif-
ferentiated. Herrick (1888, vol. 4, pl. 4, fig. 18) and Hyde
(1953, pl. 40, figs. 28-32) have illustrated specimens from
the Waverly group which are clearly conspecific with speci-
mens of Palaconcilo truncata from the Coldwater forma-
tion. Vhe fact that Hall’s specimens are also from the
71 PALAEKONTOGRAPHICA AMERICANA (V, 35)
Waverly has persuaded the writer that they are conspecific
with Coldwater forms.
Winchell (1862, p. 415) described, but did not figure,
Sanguinolites marshallensis from the Marshall sandstone
of Michigan. Winchell’s type specimen of this species
(UMMP, No. 26877) is figured here for the first time on
Plate 16, figures 1-3. It is clear from examination of these
Winchell [=
Parallelodon (Cosmetodon) marshallensis] is not conspe-
figures that Sanguinolites marshallensis
cific with Palaconeilo truncata Hall. This fact was sus-
pected! by Elyde’ (11953; pp. 2977)),
lem in some detail.
who discussed the prob-
Herrick (1888, vol. 3, p. 67), at the suggestion of Win-
chell, identified certain Waverly specimens, here considered
conspecific with P. truncata, as identical with Sanguino-
lites marshallensis Winchell. Later, Herrick (1893, ex-
planation of plate 16) recognized that his specimens from
the Waverly were identical with P. truncata Hall, which
he believed to be conspecific with S$. marshallensis Win-
chell [= Parallelodon (Cosmetodon) marshallensis (Win-
chell) }. The writer has not seen representatives of Paral-
lelodon (Cosmetodon) marshallensis trom the Waverly
group. Such forms may exist, but they are not those which
have previously been assigned to Sanguinolites marshal-
lensis, these forms belonging in reality to Palaconcilo
truncata Hall.
Types and occurrence.—TVhe six hypotypes here consid-
ered (UMMP, Nos. 43878, 43879, 43955-43958) are from
glacial drift at Kalamazoo, Michigan. It is assumed that
these were originally from the Coldwater formation. In
Ohio Palaeoneilo truncata is reported by Hyde (1953, p.
296) from the Byer member of the Logan formation at
Sciotoville, from the Vinton member at Rushville, and as
probably occurring in the Allensville member at Newark.
Weller (1899, p. 33) and Branson (1938, p. 37) reported P.
truncata from the Northview siltstone of Missouri.
FAMILY NUCULIDAE
Genus NUCULOPSIS Girty, 1911
Nuculopsis Girty, 1911, p. 133; 1915, pp. 115-117; Schenck, 1934, pp.
29-30; Elias, 1957, pp. 746-748; (see Schenck, 1934, for other refer-
ences).
Type species.—By original designation Nucula ventri-
cosa Hall (Girty, 1911, p. 133) [=Nuculopsis girtyi
Schenck (1934, p. 30), non Nucula ventricosa Hinds (1843,
p. 100) J.
Remarks.—Schenck (1934, pp- 29-30) pointed out that
Girty did not fully characters of
Nuculopsis. OF particular importance is the presence of a
understand certain
chondrophore. Schenck (1934, p. 30) said that “Phe name
[Nuciulopsis| however, has value... since it is the earliest
one to be applied to Paleozoic nuculids with a smooth
ventral margin, and, as far as I can tell, without definite
concentric ribs, as in Nuculoma.” Elias (1957, pp. 747-748)
pointed out that Schenck later (1939) placed in Nuculopsis
certain ribbed species.
Palaeonucula Quenstedt (1930, p. 112) and Nuculopsis
sensu stricto have been designated as subgenera of Nuculop-
sis by Schenck (1934, p. 36). The principal difference be-
tween the two type species appears to be that the beaks of
Nuculopsis girtyt Schenck (=Nucula ventricosa Hall, non
Nucula ventricosa Hinds) are more strongly opisthogyrate
(Defrance) . This
morphologic difference does not seeem to the writer to
warrant subgeneric differentiation.
than those of Palaeonucula hammeri
Girty (1915, pp. 115-117) discussed the orientation of
shells of the Nuculidae and Ledidae. He concluded that
the beaks of Nuculopsis point toward the short end of the
valves and that this end is anterior. Girty based his con-
clusion on the existence of a supposed ligamental groove
along the hinge margin on the long end of the valves.
Schenck (1934, p. 29) said that “An examination of a
number of Recent specimens of Nucula that have lunular
areas like that of the type of Nuculopsis proves to my satis-
faction that the ligament of the Paleozoic species was in-
ternal.” He stated (pp. 29-30) that “. there is no
reason for believing that the short side of the shell is an-
terior in the case of Nuculopsis.”
The writer believes that accessory muscle scars in the
protobranch mollusks may prove useful for establishing
orientation in fossil species (see also the discussion of
Ctenodonta) .
Heath (1937, pp. 10-14, pls. 1-10) illustrated an anterior
protractor-retractor series of muscles in numerous species
of Nucula, Acila, Yoldia, and other Recent genera. Speci-
mens of Ennucula and Nucula figured by Shcenck (1934,
pl. 3, fig. 4; pl. 5, figs. 1, la) demonstrate the presence of
a corresponding anterior series of scars.
In many fossil forms a series of accessory muscle scars is
preserved on either the short or long end of the valve.
Hall figured Nucula lirata (1885, pl. 45, figs. 24, 25),
Nucula randalli (1885, pl. 45, figs. 26, 27), and Nucula
corbuliformis? (1885, pl. 46, figs. 10, 11, 35, 36). All of
these should be referred to another genus, possibly Nucu-
lopsis, because they do mot have a crenulated ventral
margin. In any case, each of these species shows a series
of accessory muscle scars on the long end of the valve.
This end, contrary to Hall’s belief, is anterior. The writer
believes these scars represent the points of attachment of
the anterior pedal protractor-retractor muscles.
A similar series of scars is found in Ctenodonta stella
(Pl. 7, figs. 1, 2, 4, 17; text-fig. 1) but, in this case, the
scars are on the short end of the valve, leading the writer
to believe that this end is anterior.
Nuculopsis houghtoni (Stevens)
Pl. 8, figs. 1-16; text-figure 2
| Nucula houghtoni Stevens, 1858, pp. 262-263. Non Nucula houghtoni
Hall, 1885, pp. 323-324, pl. 45, figs. 29-31 (—Nuculopsis sectoralis),
non Nucula houghtoni Grabau and Shimer, 1909, p. 396, text-fig.
305.
Original description.— (Stevens, 1858, pp. 262-263)
Shell equivalve, longer than wide. Beaks obtuse, not incurved. An-
terior extremity truncate. Posterior acute. Surface smooth. The cast
shows pedal muscular impressions at ‘the base of the beak. Posterior
adductor muscular impression strong, elevated, semicircular, situated
at the posterior extremity of the hinge line. Anterior adductor scar
fainter and smaller. Hinge-line armed with 9 robust triangular teeth,
hollowed at the base and strengthened by strong lateral ridges. Teeth
pointing towards the beak, and rising in an arched form from the
hinge-line: the inner 3 being 0.1 of an inch, while the outer are
only 0.5 of an inch.
Length 0°7 of an inch; height 0°4 of an inch.
Battle Creek, Michigan.
Revised description.—Equivalved, inequilateral, —elon-
gate-oval nuculids. Ventral border evenly curved, abruptly
rounded below the mid-height of the valves into nearly
straight posterodorsal margin. Dorsal margin straight cury-
ing evenly into anterior margin which is extended into
rounded point at anterior extremity. Posterodorsal margin
and dorsal margin join below beaks at an angle of from
about 113° to approximately 121°.
Valves closed all around, gibbous, greatest thickness
occurring near mid-length of valves, greatest convexity in
umbonal region. Prominent, broad swelling extends from
umbo towards anterior margin along anterior umbonal
slope. A faint sulcus is occasionally developed extending
from umbonal region, near prominent accessory muscle
scar, ventrally and slightly anteriorly; disappears before
reaching ventral margin. Beaks curved inward above hinge
line.
Shell thick, external ornamentation fine, closely and
irregularly placed, concentric striae which become weaker
above swelling of anterior umbonal slope (PI. 8, figs. 4, 5,
12).
Pallial line entire, occasionally reflects the weak sulcus
extending ventrally from umbo (PI. 8, fig. 1). Adductor
muscle scars prominent and nearly terminal. On both an-
terior and posterior adductor scars the edge farthest from
the margin of the valve is most deeply impressed, standing
out clearly on internal molds (PI. 8, figs. 1, 3, 6, 9, 10).
Anterior adductor scar large elongate-oval, situated an-
terior to farthest anterior extension of dentition and
covering most of the anterior extremity of valve. Posterior
adductor scar terminal but slightly more ventral than an-
MIUSsSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLL
~I
Dorso-—
median Anterior pedal
retractors
Ventro—
median Anterior pedal
protractor ?
Text-figure 2—Composite drawing of Nuculopsis houghtoni
(Stevens) from natural internal molds. Small nodes in umbonal re-
gion indicate positions of accessory muscle scars. Note strong elongate
scar of dorsomedian and ventromedian muscles.
terior adductor, somewhat smaller and not so elongate,
broader toward base, roundly pointed toward beak.
Accessory muscle scars commonly preserved in umbonal
region, characterized by a single strong elongate scar ex-
tending ventrally from near the beaks (PI. 8, figs. 2, 16;
text-fig. 2). This principal accessory scar, thought to
represent the point of attachment of the dorsomedian and
ventromedian muscles, is bounded laterally by two small,
elongate ridges, which appear as grooves in internal molds.
Anterior to dorsomedian and ventromedian scars three
small scars are found on the anterior umbonal slope. These
are thought to reflect the attachment of the anterior pedal
retractor muscles. Directly above anterior adductor and
immediately adjacent to anterior extremity of dentition,
is small, sharply defined, subcircular scar, which is thought
to be caused by an anterior pedal protractor muscle (PI.
8, fig. 7; text-fig. 2). There are also indications of scars
posterior to the dorsomedian and ventromedian muscle
scars but these do not allow proper definition (PI. 8, fig. 2;
text-fig. 2).
Dentition taxodont. Chevron-shaped teeth anterior and
posterior to beaks are smaller near the beaks and near
the extremities, largest in the central part of the anterior
and posterior series of teeth (PI. 8, figs. 13, 15). Teeth
inclined slightly toward beaks. Dentition not interrupted
below beaks but teeth become minute, change direction,
and are limited to dorsal part of hinge line above chon-
drophore. Chondrophore symmetrical, triangular above,
rounded below, extends ventrally into shell cavity, not
inclined (PI. 8, fig. 13).
76 PALAEONTOGRAPHICA AMERICANA (V, 35)
Ten teeth counted anterior to chondrophore, six teeth
posterior to chondrophore. Six minute teeth present above
chondrophore, four anterior and two posterior. Number of
teeth probably varies with size of specimen.
Remarks.—The original description given by Stevens
of Nucula houghtoni fits sufficiently well the specimens here
considered. The writer believes them to belong to a single
species. Stevens said (1858, p. 263), “Teeth pointing
towards the beak and rising in an arch from the hinge-
line ”’ The arched form is thought to refer to the
variation in tooth size discussed above. The beaks are
blunt as was noted by Stevens but, contrary to his belief,
they do curve slightly inward above the hinge line. This
character is not obvious from observation of exterior, but
becomes apparent on examination of internal molds.
Muscle scar pattern, general form, dentition, and es-
pecially the height/length ratio described by Stevens, are
closely similar to that of the present specimen. Apparently
Stevens considered the short end of the valves as anterior
and this must be taken into account in evaluating his de-
scription. From Stevens’ description, the height/length
ratio of Nucula houghtoni is 1/1.5, Four specimens from
glacial drift at Kalamazoo, Michigan, which were measured
by the writer give a range of height/length ratios from
1/1.50 to 1/1.56.
In contrast to this rather constant ratio, measurements
of four of Weller’s (1901, pp. 172-173) six hypotypes
(UMMP, Nos. 2145, 44005-44009) of Nucula iowensis give
ratios ranging from 1/1.17 to 1/1.29. The other two hypo-
types are not suitable for height/length measurements.
From Winchell’s description (1862, p. 418) of Nucula
Nuculopsis sectoralis) the height/length ratio
is calculated to be 1/1.17. Winchell’s description of Nucula
iowensis (
sectoralis (= Nuculopsis sectoralis of present paper)
(1862, pp. 418-419) yields a height/length ratio of 1/1.16,
and Hall’s (1885, pp. 323-324) figures for Nucula hough-
toni (=Nuculopsis sectoralis of present paper) from the
Marshall sandstone near Hillsdale and Battle Creek, Michi-
gan, give a height/length ratio of 1/1.30 (although meas-
urement of the specimen, AMNH. No. 6539/1, yields a
slightly larger ratio). Clearly, Nuculopsis houghtoni
(Stevens) is more elongate than any of the other species
here considered.
Herrick (1888, vol. 3, p. 78, pl. 5, fig. 17; 1888, vol. 4,
peta plied fies 3) pl. 10. fis. 4511889) pl. 25 fie:3; 11893; pl:
16, fig. 3; pl. 21, fig. 17; pl. 23, fig. 6) described and figured
certain specimens which are closely related to Nuculopsis
houghtoni (Stevens). The figures, however, are poor and
the descriptions are not detailed enough to allow the writer
to reach satisfactory conclusions concerning Herrick’s speci-
mens. It is possible that some of the specimens which
Herrick described are synonymous with Nuciulopsis hough-
toni, but further work will be necessary before this can
be properly established.
Nuculopsis houghtoni, though smaller, resembles in
general form Hall’s (1885, pp. 515-316, pl. 45, figs. 6-10, 16,
23; pl. 93, figs. 1-3) description and illustrations of Nucula
randalli from the Hamilton group of New York. Other
than the smaller size, Nuculopsis houghtoni may be dis-
tinguished by its prominent elongate accessory muscle scar
in the umbonal region, the less strongly incurved beaks,
the more irregular surface sculpture, and the larger size
and distinctive shape of the adductor muscle scars.
Types and occurrence—The syntypes of Nuculopsis
houghtoni (Stevens) from Battle Creek, Michigan, are
probably lost. The six hypotypes considered, UMMP,
Nos. 43983-43988, are all from glacial drift at Kalamazoo,
Michigan. Because of their lithology, they are considered to
have originated in the Marshall sandstone. As mentioned
above, the species may have been reported from Ohio by
Herrick, but this is not yet certain.
Di |
Anterior pedal
retractors
Ventro—
median
Anterior pedal
aa
Text-figure. 3—Composite drawing of Nuculopsis sectoralis (Win-
chell) from natural internal molds. Small, weak, nodes in umbonal re-
gion indicate positions of accessory muscle scars.
Nuculopsis sectoralis (Winchell)
Pl. 7, figures 34-36; Pl. 8, figures 17-38; text-figure 3
Nucula sectoralis Winchell, 1862, pp. 418-419.
Nucula iowensis Winchell, 1862, p. 418. Non Nucula iowensis White
and Whitfield, 1862, p. 298; mec Nucula towensis Weller, 1901,
pp. 172-173, pl. 15, figs. 8, 9; mec Nucula towensis Van Tuyl, 1924,
plasietigss 222s.
Nucula houghtoni Hall,
Nucula houghtoni Stevens,
houghtont (Stevens) |.
323-324, pl. 45, fig. 29. Non
262-263 [= Nuculopsis
1885, pp.
1858, pp.
MIsSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLL
Original description—(Winchell, 1862, pp. 418-419).
Shell rather small, ventricose, sectiform, with nearly central beaks.
Anterior cardinal slope straight; posterior, nearly so, making with the
former an angle of 88° to 91°; ventral border sub-circular. Beaks
prominent, acute, direct incurved. Anterior hinge plate with about 17
teeth; posterior with 13, much smaller. Adductor scars subterminal,
profound, roundly oval. Surface of casts perfectly smooth.
Length ‘86 (100); height -74 (86); thickness -44 (51); distance
from beak to line joining extremities “40 (46); length of anterior
end 51 (59); of posterior end 35 (41).
Locality—Battle Creek and Grindstone Quarries, Pt. aux Barques.
Revised description.—Equivalved, inequilateral, sub-tri-
angular nuculids. Ventral border evenly curved, rounded
evenly upward into nearly straight posterodorsal margin.
Rounded anterior border curves evenly into nearly straight
dorsal margin. Posterodorsal margin and dorsal margin join
below beaks at variable angle of about 100° to about 115°.
Valves closed all around, only moderately swollen, great-
est thickness occurring posterior to mid-length of valves.
Beaks curved slightly inward above hinge line.
Shell thick; external ornamentation of fine, closely and
irregularly placed concentric striae (PI. 8, figs. 37, 38) ;
pallial line entire; adductor muscle scars prominent, nearly
terminal (PI. 8, figs 24, 35). On both anterior and pos-
terior adductor scars the edge nearest the center of the
valve is most deeply impressed. Anterior adductor scar
large, elongate oval, situated approximately at mid-height
of valve, anterior to farthest anterior extension of dentition.
Posterior adductor scar terminal, slightly more dorsal than
anterior adductor, smaller, broad toward base at posterior
extremity, roundly pointed toward beak.
Acccessory muscle scars occasionally preserved but not
strongly impressed, consisting of a series of two or three
scars on anterior umbonal slope. The most posterior of
these scars, located near umbo, is thought to represent dor-
somedian muscle, Others probably are points of attachment
for anterior pedal retractor muscles. A small distinct,
elongate oval scar present subparallel to hinge line im-
mediately above and posterior to anterior adductor is
thought to be the anterior pedal protractor scar (PI. 8, figs.
18, 36). Muscle track of this scar occasionally preserved
along anterior umbonal slope (PI. 8, fig. 18). Below the
series of three or four scars on anterior umbonal slope is
weakly developed indication of ventromedian muscle scar.
Less well-developed accessory scars, not clearly differenti-
ated, are present in umbonal region (PI. 8, figs. 34, 35;
text-figure 3) .
Dentition taxodont; teeth with slight chevron shape
anterior and posterior to beaks, point toward beaks; teeth
smaller near beaks and near extremities, largest in central
part of anterior and posterior series of teeth (Pl. 8, figs.
28, 30); teeth inclined slightly toward beaks.
~xI
x
Asymmetrical chondrophore situated beneath beaks, sub-
triangular, inclined, extending ventrally and anteriorly into
shell cavity (Pl. 8, fig. 27). Dentition probably extends
above chondrophore; no complete dentition series ob-
served, ten teeth counted anteriorly, four posteriorly.
Remarks.—Four specimens labeled “Nucula Iowensis
White and Whitfield” by Winchell are preserved at the
University of Michigan (UMMP, Nos, 27761, 44016-44018) .
A fifth specimen, UMMP, No. 44015, was figured by Win-
chell (previously unpublished, see Pl. 7, fig. 34 of present
paper), and the figure was labeled “Nucula Iowensis W &
Whitf.” These specimens are from Battle Creek, Calhoun
County, Michigan, and were in Winchell’s possession at
the time he described Nucula iowensis.
Comparison of Winchell’s specimens with six hypo-
types of Nucula iowensis which were described by Weller
(1901, pp. 172-173, pl. 15, figs. 8, 9) from bed No. 5 of
the Kinderhook at Burlington, Iowa, (UMMP, Nos. 2145,
44005-44009) has convinced the writer that Winchell’s
Michigan specimens are distinct. They are, however, similar
to Weller’s Iowa specimens which, in fact, belong in the
genus Nuculopsis. Five of Weller’s six hypotypes (UMMP,
Nos. 44005-44009) are here illustrated (PI. 7, figs. 19-29)
for comparison with Nuculopsis sectoralis (Winchell) .
‘Two of these specimens, UMMP, Nos. 44008, 44009, were
previously figured by Weller (1901, pl. 15, figs. 8, 9 respec-
tively) .
Nuculopsis sectoralis and Nuculopsis towensis (White
and Whitfield) are similar in size, general shape, place-
ment and shape of adductor and anterior pedal protractor
muscle scars, curvature of beaks, dentition, and possession
of an asymmetrical chondrophore inclined anteroventrally.
Nuculopsis sectoralis may be distinguished by its more
nearly central beaks, more nearly triangular shape, more
strongly impressed adductor scars, and the presence of
accessory muscle scars in the umbonal region. Possibly
better preserved specimens of Nuculopsis iowensis (White
and Whitfield) will also show accessory scars but these
are not preserved on specimens which the writer has ex-
amined.
One of the specimens described as Nucula houghtoni
by Hall (1885, pp. 323-324, pl. 45, fig. 29) (AMNH, No.
6539/1) has been examined. This specimen, collected from
the Marshall sandstone at Battle Creek, Michigan, is
figured here on Plate 7, figure 56. The other two specimens
figured by Hall (1885, pl. 45, figs. 50, 31) , both of which are
from Ohio, are probably lost. Though poorly preserved and
somewhat larger than most members of the species, the
specimen which Hall described as Nucula houghtoni from
78 PALAEONTOGRAPHICA AMERICANA (V, 35)
3attle Creek, agrees in all observable characters with Nu-
culopsis sectoralis and is here considered synonymous.
At the same time that Winchell described Nucula towen-
sis White and Whitfield from Michigan (1862), he also
(pp. 418-419) described Nucula sectoralis Winchell. Seven
specimens (UMMP, Nos. 26875, 44022-44027) which were
in Winchell’s possession at the time of his description, have
been examined. They were all labeled Nucula sectoralis
by Winchell. Three of these (UMMP, Nos. 44025-44027)
belong, in reality, to the genus Schizodus. The other four
specimens (UMMP, Nos. 26875, 44022-44024) which fit
more nearly Winchell’s original description, are here con-
sidered as syntypes.
Girty (1928, pp. 119-120)
mens of Nucula sectoralis and concluded that “N.
discussed Winchell’s speci-
sector-
alis may be dismissed as soon as mentioned. Under that
species Winchell included shells belonging to both Nucula
and Schizodus, and unfortunately the type specimen of N.
sectoralis is of the latter genus.” The writer finds no rea-
son to dismiss Nucula sectoralis. There is no reason to
assume that the type specimen of N. sectoralis belongs to
Schizodus. Winchell, in fact, did not designate a single
type, working rather with what he believed to be a syn-
typic series. Winchell’s description of N. sectoralis clearly
indicates that the form he discussed possesses taxodont den-
tition, a character not present in Schizodus.
It seems probable from this confusion of specimens that
Winchell himself did not fully understand the differences
he wished to describe. The principal distinction between
Nucula iowensis as described by Winchell (1862, p. 418)
and Nucula sectoralis Winchell (1862, pp. 418-419) is that
the latter was said to have nearly central beaks, whereas
those of N. cowensis were referred to as subterminal. This
difference was not observed in the specimens examined by
the writer. The reproduction of Winchell’s unpublished
illustrations of these two species (PI. 7, figs. 34, 35, of
present paper) also indicates that Winchell did not clearly
differentiate N.
sectoralis from N. iowensis.
Nuculopsis sectoralis (Winchell) is distinguished from
N. houghtoni (Stevens) by the former’s more nearly tri-
angular shape, less elongate form, and less prominent mus-
cle scars. The anterior pedal protractor scar of N. sectoralis
is an elongate oval whereas that of N. houghtoni is charac-
teristically circular. The chondrophore of N. sectoralis is
asymmetrical and projects into the valve cavity inclined
in an anteroventral direction whereas the symmetrical
chondorphore of N. houghtoni projects in a ventral direc-
tion. N. sectoralis is less gibbous and has its greatest thick-
ness more posteriorly than N. houghtoni. The distinctive
elongate accessory muscle scar, the dorsomedian scar, in
the umbonal region of N. houghtoni is absent in N. sector-
alis; nor does N. sectoralis possess any indication of a sulcus
extending ventrally from the umbo.
Plate 7, figures 30-33, illustrates certain specimens
(UMMP, Nos. 44029-44030) of Nuculopsis from the Way-
erly group at Medina, Ohio. ‘The strongly impressed muscle
scars and general form of these specimens is similar to that
illustrated for Nucula lirata (Conrad) by Hall (1885, pl.
15, fig. 25). Because this species does not occur in the
Marshall sandstone it will not be discussed in detail. Tt may
be distinguished from Nuculopsis iowensis by its more
prominent muscle scars, more posterior beaks, and more
numerous accessory muscle scars.
Types and occurrence.—Winchell’s four syntypes of Nu-
cula sectoralis from Battle Creek, Michigan, have been ex-
amined. UMMP, No. 44022 is here designated lectotype
of Nuculopsis sectoralis. The remaining three specimens,
UMMP, Nos. 26875 (not figured), 44023, and 44024 (not
figured) are paralectotypes. Winchell (1862, p. 419) also
reported Nucula sectoralis from “Grindstone Quarries,
Pte. aux Barques Michigan.” I have studied a single speci-
men from this locality (UMMP, No. 27758) which was
considered by Winchell as a syntype of Nucula sectoralis.
‘This specimen is so poorly preserved that the writer is not
able to identify it properly and does not regard it as a
paralectotype of Nuculopsis sectoralis (Winchell) .
Winchell’s five hypotypes of Nucula towensis from
Battle Creek, Michigan, (UMMP, Nos. 44015-44018, 27761)
are all considered hypotypes of Nuculopsis sectoralis. Of
these, only Nos. 44015 and 44016 have been figured. Win-
chell’s hypotype of Nucula iowensis from Kent County,
Michigan, UMMP, No. 26892, is too poorly preserved for
identification.
The writer here figures five additional hypotypes of
Nuculopsis sectoralis (Winchell). UMMP, No. 44014 is
from Battle Creek, Michigan; UMMP, No, 44013 is from
Marshall, Michigan; and UMMP, Nos. 44010-44012 are
from glacial drift at Kalamazoo, Michigan. Because of thei
lithology, these drift specimens are thought to have origi-
nated in the Marshall sandstone.
In summary, Nuculopsis sectoralis is known to occur
only in the Marshall sandstone at Battle Creek and Mar-
shall, Michigan.
FAMILY NUCULANIDAE
Genus POLIDEVCIA Chernyshev, 1951
Polidevcia Chernyshev, 1951, p. 25; Elias, 1957, p. 750; Kumpera,
Prantl and Razicka, 1960, pp. 34-38 (see Kumpera, Prantl and
Riizicka, 1960, for other references).
MASSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLI 79
Type species.—By original designation, Leda karaganden-
sis Cherynshey, 1941.
Polidevcia pandoraeformis (Stevens)
Pl. 10, figures 16-34
Leda pandoraecformis Stevens, 1858, p. 262. Non Leda pandoriformis
Hall 1885, p. 332, pl. 47, figs. 49, 50 (= Leda ohioensis Hall, 1884a,
pl. 7, fig. 3); mec Leda pandoriformis Grabau and Shimer, 1909,
p. 401, text-fig. 511, a, b; mec Leda pandoriformis? Girty, 1915a,
pp. 84-85, pl. 8, figs. 15, 16.
Leda bellistriata Winchell, 1862, p. 419; 1865, p. 128. Non Leda
bellistriata Stevens, 1858, pp. 261-262; nec Leda bellistriata? Win-
chell (in Safford, 1869, pp. 441, 444); mec Leda_ bellistriata?
Winchell, 1871, p. 256.
Original description.— (Stevens, 1858, p. 262) .
Shell (cast) flat but moderately inflated at the umbones. Beaks
near middle of the shell, wide at the umbones. Anterior extremity
broadly rounded. Posterior much produced, attenuated and rostrated.
In the cast a strong ridge is seen, descending from the beak and
curving with the hinge-line, reaches the posterior extremity. Another
strong ridge descends from the beak more abruptly to near the ven-
tral margin and then proceeds parallel to the former ridge, until lost
in the rostrated extremity, leaving a wide deep fossa between them.
Shell exhibits on the surface strong longitudinal lines of growth,
arranged in triple series. Cast resembles the Pandora, and_ hence
the specific name. Teeth scarcely visible, probably 10 anterior, 20
posterior, long and slender.
Battle Creek, Michigan.
Revised description.—Thin, opisthogyrate; ventral margin
gently curved; anterior border curved evenly from beaks,
more abruptly but evenly around anterior extremity, and
evenly into ventral margin, giving a semiovate anterior
outline; dorsal margin between beaks and posterior ex-
tremity strongly concave upward; posterior end of shell
extended, attenuated, and subrostrate, its extremity sharp-
ly rounded or subtruncate.
Valves thin, greatest convexity in umbonal region.
Strongly opisthogyrate beaks located near the midlength
of valves, greatest thickness below beaks. Strong umbonal
ridge, concave upward, extends posteriorly from beaks,
subparallel to dorsal margin, to posterior extremity. Be-
tween umbonal ridge and hinge line, in area not occupied
by escutcheon, is distinct, elongate, flat area marked by
prominent, sharp, but somewhat irregular ridges sub-
parallel to hinge line (PI. 10, fig. 24).
Escutcheon small, lanceolate, weakly set off from flat,
ridged area by indistinct curved ridge, and marked by weak
undulations perpendicular to hinge line (PI. 10, fig. 24).
These undulations apparently reflect positions of teeth
and sockets below escutcheon.
Narrow, distinct ridge extends from umbo anteriorly
along dorsal margin (PI. 10, fig. 23). Thin elongate in-
distinct lunule-like area present between this ridge and
valve border.
Thickening in shell produces internal ridge extending
anteriorly from near ventral part of posterior extremity
(PI. 10, figs. 21, 31) . Ridge is lost about 1/3 of valve length
from. posterior extremity. i
Taxodont dentition, long, thin, chevron-shaped_ teeth,
convex toward umbo, present anterior and posterior to
beaks, limited to central part of dorsal margin (PI. 10, fig.
27). Anteriorly, teeth extend about 1% of distance from
beaks to anterior extremity. Posteriorly, teeth terminate
about 1% of distance from beaks to posterior extremity.
Maximum number of teeth counted anteriorly, 12. Maxi-
mum number counted posteriorly, 16. Small resilifer in-
terrupts dentition below beaks, but small, reduced teeth
may pass above this structure (PI. 10, fig. 27) .
Surface sculpture of fine nonbifurcating, sharp, concen-
tric ribbing, which disappears posteriorly, not passing over
posterior umbonal ridge (PI. 10, figs. 24, 25) and which
becomes weaker on anterior part of valve. On umbonal
ridge only weak, indistinct growth lamellae are present.
Above umbonal ridge are distinct but somewhat irregular
ridges subparallel to hinge line on flattened area (Pl. 10,
fig. 24) .
Remarks.—Yhe writer has finished (1965) a study of
certain Mississippian, Pennsylvanian, and Permian forms
belonging to the genus Polidevcia. This study will appear
elsewhere. A detailed comparison of P. pandoraeformis
with closely related forms is deferred for the present. How-
ever some comments, particularly upon synonymy, seem
appropriate.
Species of Leda and Nuculana described from the Mar-
shall sandstone present a difficult problem in nomencla-
ture. In 1858 Stevens (p. 262) described three new species
of Leda from the Marshall sandstone at Battle Creek,
Michigan; L. densmamillata, L. nuculacformis, and L. pan-
doraecformis. The descriptions lack precision, no figures were
published, and the types are apparently lost.
Leda densmamillata is said by Stevens to possess certain
rather distinct structures, ¢.g., nearly terminal beaks, seven
distinct pedal muscle scars, and 25 teeth, all of which are
posterior. Subsequent to Stevens’ description this form
has not been reported from the Marshall sandstone or
elsewhere by any worker. The writer, in examination of
the Marshall collections at the University of Michigan, is
not able to assign any forms to L. densmamillata nor to
determine the synonymy of that name. It appears that the
name should be abandoned.
Leda nuculaeformis is almost as poorly understood as the
preceding species. Herrick (1888, vol. 4, p. 45, pl. 4, fig. 23;
1889, pl. 2, fig. 23; 1893, pl. 16, fig. 23) tentatively identi-
fied it from the Waverly group at Newark, Ohio, and Girty
(1915a, p. 86, pl. 8, fig. 14) reported another tentative
SO PALAEONTOGRAPHICA AMERICANA (V, 35)
identification from shells in the Batesville sandstone of
northern Arkansas. This form has not been subsequently
described or figured from the Marshall sandstone.
The writer, in examination of the Marshall sandstone
fauna, has found only a single species of the family Nu-
culanidae, Polidevcia pandoraeformis. Alexander Winchell,
in his extensive work on the Marshall fauna, also en-
countered only this one species of the family although he
called it Leda bellistriata.
The writer strongly suspects that Polidevcia pandorae-
formis is, in fact, the sole Marshall representative of the
family. If this is true, the lost specimens described by
Stevens as Leda nuculaeformis probably were misidentified.
Stevens’ description might easily fit certain of the Palaeo-
neilos common in the Marshall sandstone. On the other
hand, the specimens described by Herrick and by Girty
may be correctly assigned to Nuculana.
Polidevcia pandoraeformis (Stevens) is clearly distinct
from Nuculana bellistriata (Stevens) [= Polideucia bel-
listriata (Stevens) ]. The former is distinguished by being
thinner, commonly larger, and more opisthogyrate. The
beaks of P. pandoraeformis are near the center of the
valves, and it is at this point that the greatest thickness
occurs. In P. bellistriata the beaks are anterior to the middle
of the valves, as is the greatest thickness. ‘The anterior mar-
gin of P. bellistriata, as opposed to that of P. pandoraefor-
mis, does not curve evenly into the beaks, which are slightly
elevated above the anterodorsal margin. Concentric sur-
face sculpture of P. pandoraeformis is fine and becomes
weaker anteriorly, whereas that of P. bellistriata is some-
what coarser and continues anteriorly without change.
It appears that Polidevcia bellistriata is limited to the
Pennsylvanian and Permian systems, and its extension into
the Mississippian is unsubstaniated.
Winchell (in Safford, 1869, p. 444) described certain
specimens, UMMP. No. 26731, from Hickman or Maury
County, Tennessee, as Leda bellistriata? These specimens
have not been figured previously. ‘Two of them are illus-
trated in the present paper (PI. t0, figs. 35, 36). They differ
from Polidevcia pandoraeformis in being less opistho-
gyrate, having more anteriorly placed beaks, and_possess-
ing strong concentric surface ornamentation on the an-
terior part of the valves.
Girty (1928, p. 121) suggested that Nuculana (Leda)
spatulata Herrick, Nuculana (Leda) similis Herrick, and
Leda pandoriformis as figured by Hall (1885, pl. 47, figs,
19, 50) may well be synonymous. This may, in fact, be true.
However, none of these forms are here considered to repre-
sent Polidevcia pandoracformis (Stevens). Adult members
of N. spatulata, N. similis, and the specimens figured as L.
pandoriformis by Hall all appear to possess beaks which
are anterior to the midlength of the valves. This is not true
in Polidevcia pandoracformis (Stevens). It is noteworthy
that immature forms of the present species sometimes lack
centrally situated beaks (PI. 10, fig. 17). Apparently the
valves of this species become more opisthogyrate with age.
Thus, the differentiation of immature specimens presents
considerable difficulty.
Girty (1928, p. 121) suggested that “We do not at present
know and perhaps never shall know what species Stevens
wished to designate by L. pandoriformis [sic], as his de-
’ He proposed
that use of the name should be discontinued. Leda pan-
doracformis was first reported from the Marshall sandstone
at Battle Creek, Michigan. Because the specimens here
scription lacks precision on many points.’
described fit Stevens’ original description fairly well, and
because no closely related species are thought to be pres-
ent in the Marshall sandstone, the writer chooses to retain
Stevens’ name.
Types and occurrence—The Stevens types of Polidevcia
pandoraeformis are presumed to be lost. The specimens
from Moscow, Hillsdale County, Michigan, and Battle
Creek, were described by Winchell
(1862, p. 419), are preserved at the University of Michi-
gan. They are, respectively, hypetypes (UMMP, Nos. 29465
and 27762). The specimens which Winchell described in
1865 (p. 128) are hypotypes (UMMP, Nos. 35716, 35718,
27053). Of these only No. 27053 is here figured (PL. 10,
figs. 29-31) .
The writer figures as hypotypes UMMP, Nos. 44060
and 44061 from Mosherville, Hillsdale County, Michigan;
No. 44063 from Moscow, Hillsdale County, Michigan; and
No. 44062 from Marshall, Calhoun County, Michigan.
UMMP, No. 44059, from Mosherville, Hillsdale County,
Michigan, is here designated the neotype. It would, per-
haps, be preferable to choose a neotype from topotype speci-
mens. Unfortunately, the only specimen from Battle Creek
which is preserved in the University of Michigan collections
is only a posterior extremity. This specimen, UMMP, No.
27762, which was described by Winchell (1862, p. 419)
is figured on Plate 10, figure 32.
Michigan, which
Three specimens of Polidevcia pandoracformis (OUMMP,
Nos. 44064-44066) from glacial drift at Kalamazoo, Michi-
gan, are figured for comparison with Marshall forms (PI.
10, figs. 16, 18, 33). The lithologic association of these speci-
mens indicates that they probably originated in the Cold-
water shale.
Polideveia pandoracformis (Stevens) occurs in the Mar-
MISSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOTLI SI
shall sandstone of Michigan at numerous localities in the
southern part of the state and probably in the Coldwater
shale. No other occurrences of the species are known to the
writer. There are, however, closely related species in the
Waverly group of Ohio; e.g., the specimens described as
Leda pandoraeformis by Hall (1885, p. 332, pl. 47, figs. 49,
50) .
FAMILY SOLENOMORPHIDAE
Genus PROTHYRIS Meek, 1869
Prothyris Meek, 1869, p. 172; 1871, p. 8; 1872, p. 223; Hall, 1885,
p. xl; Whidborne, 1896, p. 86; Clark, 1913, pp. 187-189; Elias,
1957, pp. 741-742.
Type species —By monotypy and subsequent designation,
Prothyris elegans Meek, 1871, pp. 8-9, pl. 1, fig. 3.
Remarks.—Hall (1885, p. xli), Miller (1889, p. 458) , and
Whidborne (1896, p. 86) included Prothyris in the family
Prothyridae. Because only Prothyris has been included in
the Prothyridae, and because the distinctions between Pro-
thyris and Solenomorpha do not appear to be of familial
rank, the writer follows Branson (1938, p. 77), including
Prothyris in the Solenomorphidae. It should be noted that
Branson (1938, p. 77) was apparently not aware that
Cockerell (1915, p. 84) changed the name Solenopsidae to
Solenomorphidae because the generic name Solenopsis was
preoccupied.
Whidborne (1896, p. 86) said:
There seems one discrepancy between the genus [Prothyris] as
generally defined and the characters shown by English species; viz.
that the notch in the latter is the termination of an elevated ridge
running from the umbo, and not of a groove, as appears indicated
by Meek, Hall, Zittel, Fischer, &c. Whether this points to a real
difference I cannot say, but the character of the ridge in English
species is clear.
Meek (1871, p. 8), in his first clear definition of the
genus, stated “ beaks depressed and very near the
anterior end, with a small ridge usually extending from
the anterior side of each to the corner of the anterior mar-
ginal notch... ,” thus emphasizing the importance of the
anterior ridge as a generic character.
Zittel (1885, p. 128) did not describe the genus, and
Hall (1885, p. XI), in his generic description, did not
comment on the presence or absence of an anterior ridge
or groove. However, in the same publication, Hall (pp.
460-462) included four species in the genus Prothyris. Two
of these, Prothyris planulata Hall and Prothyris alata Hall
have a distinct anterior groove terminating in an anterior
notch. In the other two, Prothyris lanceolata Hall and Pro-
thyris exuta Hall neither an anterior ridge nor an anterior
groove appear, from Hall’s plates, to be present.
Fischer (1887, p. 1111) apparently believed that an an-
terior groove rather than an anterior ridge is characteristic
of Prothyris. He said (p. 1111) in his generic description,
Sommets déprimés, subterminaux, avec un_ petit
sillon décurrent, s’etendant jusqu’a l’échancrure
The writer believes that the inclusion of forms with an
anterior groove in Prothyris is unjustified and has led to
confusion, particularly among European workers, as to the
nature of this American genus. Meek’s original definition
of the genus clearly indicates that he considered an an-
terior ridge as an important characteristic. It is probable
that the forms with anterior grooves, notably the Devon-
ian forms discussed by Hall (1885, pp. 460-462), will ulti-
mately be designated as a new genus, but further consid-
eration of these species is beyond the scope of this paper.
Furthermore, the limitation of Prothyris to those forms
possessing an anterior ridge eliminates possible confusion
with the genus Orthonota (Conrad, 1841, pp. 50-51), which
has no such ridge. Prothyris also differs from Orthonota in
the nature of its postumbonal slope, which is without
strong folds shown to be present in Orthonota by Hall
(1885, pp. 478-479, pl. 78, figs. 34-42) .
Elias (1957, pp. 741-742) may well be correct in his be-
lief that Prothyris is a subgenus of Solen but for the pres-
ent, the writer chooses to retain Prothyris as a generic term.
Prothyris rectidorsalis (Winchell)
Plate 11, figures 1-9
Orthonota rectidorsalis Winchell, 1862, p. 414, in part; ?Herrick, 1888,
3, p. 65, pl. 9, fig. 6.
Prothyris parallela Hyde, 1953, pl. 43, figs. 4-6, mom. nud.
Original description.— (Winchell, 1862, p. 414) .
Shell of moderate size, tumid, elongate transversely with subterminal
beaks and gaping extremities. Hinge margin straight, reaching nearly
to the posterior extremity of the shell, somewhat elevated; ventral
margin straight, and parallel with the dorsal; posterior extremity
truncately rounded, making with the dorsal margin an anterior angle
of 105°; anterior end slightly gaping two thirds the width of the
shell, rounded abruptly above, gradually below; beak scarcely ele-
vated above the dorsal line, flattened, incurved, with a conspicuous
lunule in front; umbonal swelling running to the lower posterior angle.
Hinge apparently edentulous and simple; pallial and muscular jm-
pressions undiscernable; a deep groove runs from beneath the beak to
the anterior extremity, which interrupts the concentric lines shown on
the interior of the shell. The cast shows five or six very faint lines
diverging from the beak along the superumbonal slope.
Length 1°48 (100); height “44 (30); convexity of right valve “10
(7); length of anterior end ‘25 (17).
Locality—Moscow, Hillsdale county.
This shell agrees tolerably well with Orthonota, as modified by
McCoy. The gaping extremities and general outline perhaps indicate
affinities with Solen.?
2McCoy (1855, p. 274) redefined Orthonota as having a“...
very deep, large lunette.” He included three species possessing such
lunules but, through his redefinition of Conrad’s genus as lunulate, he
excluded the subsequently designated non-lunulate type species, Ortho-
nota undulata. In 1885 Hall designated Orthonota undulata as the
type of the genus stating (p. xlv) that “ Mr. Conrad always
regarded [Orthonota undulata] as the typical species of the genus.”
Hall pointed out that “The anterior end is without a lunule, and
the valves continue in a straight line beyond the beaks.”
Revised description.—The following description is based
on three specimens from the Marshall sandstone, one right
valve and two left valves.
Shell solenoid, slightly tumid, equivalved, inequilateral,
length slightly more than three times height; ventral and
dorsal margins subparallel, height being slightly greater
posteriorly; dorsal margin straight posterior to beaks,
slightly depressed anterior to beaks; ventral margin straight
or very slightly sigmoidal; posterior margin diagonally
truncate, forming an angle of approximately 110° with the
dorsal margin, abruptly rounded ventrally; anterior margin
rounded upward from ventral margin, notched (Gea Ua,
fig. 5).
Valves gaping anteriorly and_ posteriorly, convexity of
valves becoming less in posterior part. Beaks 1/5 to 1/6 of
shell length from anterior end, small, depressed, well de-
fined. Moderately well-defined umbonal ridge. Postumbon-
al slope marked by two shallow grooves radiating from
the umbonal region. These may be ill-defined or suffi-
ciently distinct to give rise to a weak ridge between them.
General convexity of valves reversed immediately below
the dorsal margin posterior to the beaks, making a mu-
cronate keel of the hinge line throughout its major extent.
Internally the reversal of convexity is sharper than extern-
ally, being marked by a distinct flexure of the valve. Slight
sigmoidal character of ventral margin is a reflection of
gentle, broad sinus ventral and anterior to the umbonal
ridge.
Prominent notch in anterior margin is the termination
of distinct ridge extending from the anterior limit of the
beaks to the anterior shell margin (PI. 11, figs. 5, 8). Ridge
nearly straight, more pronounced anteriorly, reflected both
externally and internally, and forming an angle of approxi-
mately 150° with the postumbonal dorsal margin. Neither
Junule nor escutcheon present.
External and internal surface marked by numerous irreg-
ular concentric growth lines. Superimposed on growth lines
externally are numerous fine concentric striae and more
widely spaced radial sculpture, giving the shell a semiretic-
ulate appearance (PI. 11, fig. 5).
Remarks.—In 1862 (p. 414) Winchell described a new
species from the Marshall sandstone as Orthonota rectidor-
salis. Winchell’s types of this species are lost. However, a
number of specimens bearing labels written by R. A. Smith,
and presumably copied from lost Winchell labels (G. M.
Ehlers, personal communication), have been examined.
For example, two specimens, UMMP, Nos. 43058 and
43059, from glacial drift at Grass Lake, Jackson County,
Michigan, were labeled Orthonota rectidorsalis by Smith.
One of these, UMMP, No. 43059, is an unfigured hypotype
of Sphenotus obliquus.
It should be pointed out that Winchell’s description
89 PALAEONTOGRAPHICA AMERICANA (V, 35)
(1862, p. 414) of O. rectidorsalis appears to discuss char-
acters of both Prothyris and Sphenotus obliquus. The ele-
vated hinge, posterior margin, and anterior gape mentioned
by him are all characteristic of the present species, Pro-
thyris rectidorsalis. He also described a lunule and radial
sculpture on the postumbonal slope, which are characters
referable to Sphenotus obliquus. No specimen found by
the writer in the Marshall sandstone collection of the Uni-
versity of Michigan exhibits all of these characters. Due
to the confusion of specimens, absence of types, and lack
of original illustrations it might be desirable to abandon
the name Orthonota rectidorsalis. However, Herrick (1888,
vol. 3, p. 65, pl. 9, fig. 6) applied the name to specimens
which, from his description and figure, are apparently
assignable to Prothyris.
The writer chooses to retain the trivial name rectidorsalis
in reference to the specimens here described as Prothyris
rectidorsalis. Herrick (1888, vol. 3, p. 65, pl. 9, fig. 6) was
probably discussing conspecific shells. Winchell (1862,
p. 414) was discussing this species as well as certain mem-
bers of Sphenotus obliquus.
M. F. Marple edited and published (1953) the work of
Jesse E. Hyde on the Mississippian formations of Central
Ohio after Dr. Hyde’s death in 1936. In this publication
(pl. 43, figs. 4-6) certain fossils named Prothyris parallela
are figured but not described. No description of these
specimens was ever published. The name is, therefore,
invalid, being a nomen nudum. Unfortunately, the speci-
mens from which the figures were taken have been sub-
sequently lost.
The three figures of Prothyris parallela Hyde nom. nud.
appear to show internal molds. ‘There are numerous simi-
larities with Prothyris rectidorsalis. ‘The general outline,
curvature of the anteroyentral margins, depressed beaks,
umbonal slopes, subparallel dorsal and ventral margins,
and anterior ridges are all similar. The angle between the
posterior margin and the dorsal margin appears to be
somewhat greater in Dr. Hyde’s specimens than in the
writer's. This difference is not considered sufficient for
specific differentiation. Dr. Hyde's specimens are here
placed in Prothyris rectidorsalis.
Prothyris rectidorsalis is characterized by its distinct an-
terior ridge and associated byssal notch, nearly parallel
dorsal and ventral margins, the shallow diagonal grooving
on its postumbonal slope, the reversal of valve convexity
immediately below the dorsal margin, and by its surface
ornamentation.
The species differs from Prothyris elegans Meek in pos-
sessing a more distinct umbonal ridge, less depressed beaks,
MISSISSIPPIAN DIMYARIAN
and an anterior ridge which is directed more forward and
not so much in a ventral direction. The species are similar
in that they both possess subparallel ventral and dorsal mar-
gins.
Prothyris rectidorsalis is longer, relative to its height,
than any other species of Prothyris. The specimens under
examination have lengths approximately 3.2 times as great
as their heights. Prothyris elegans Meek and P. lanceolata
Hall approach P. rectidorsalis most closely in this respect,
both having lengths approximately 3.0 times their heights.
Most other species, ¢.g., P. alata Hall, P. scalprata Whid-
borne, P. planulata Hall, P. exuta Hall, P. jessieae (Miller
and Gurley), P. meeki Meek, P. contorta Whidborne, and
P. bergica Drevermann, have lengths from 2.1 to 2.7 times
their heights.
Types and occurrence.—All type specimens described by
Winchell, Herrick, and Hyde are believed to be lost. The
writer designates as neotype, UMMP, No. 36825, a left valve
from the Marshall sandstone at Marshall, Calhoun County,
Michigan. Hypotype, UMMP, No. 37297, is an internal
mold of a right valve from Moscow, Hillsdale County,
Michigan, and hypotype, UMMP, No. 43058, is a right
valve from glacial drift at Grass Lake, Jackson County,
Michigan.
Prothyris rectidorsalis (Winchell) is found in the Mar-
shall sandstone of Calhoun and Hillsdale counties, Michi-
gan, and in the Waverly group of Licking County, Ohio,
and the upper part of the Black Hand member in Vin-
ton County, Ohio.
Genus SANGUINOLITES McCoy, 1862
Sanguinolites McCoy, 1862, pp. 47-48; Hind, 1900, pp. 361-366; Wil-
liams & Berger, 1916, p. 130.
Type species—By original designation of McCoy (1862,
p. 48), Sanguinolites angustatus (Phillips) .
Sanguinolites ? herricki, sp. nov.
Plate 15, figures 1-18
?Sanguinolites unioniformis Herrick 1888, vol. 3, pp. 67-68, pl. 9,
figs. 5, 7-9 (in part). Non Sanguinolites unioniformis Winchell,
1862, pp. 414-415.
Description—TVhe following description is based on
two specimens from the Marshall sandstone at Battle Creek,
Calhoun County, Michigan, and eight specimens from
Holland, Ottawa County, Michigan.
Shell equivalved, elongate, subquadrilangular in outline,
length equal to approximately twice the height, ventral and
dorsal margins subparallel slightly higher posteriorly.
Dorsal margin rectilinear or nearly rectilinear posterior
to beak. Anterior margin descends sharply from beak,
makes angle of approximately 140° with dorsal margin.
PELECY PODS: Driscon 83
Ventral margin subrectilinear or slightly sigmoidal, rounded
abruptly upward into anterior margin. Posterior border
evenly rounded.
Prosogyrate, beaks depressed, placed above hinge line,
near the anterior extremity of valves. Umbonal ridge dis-
tinct On most specimens. Lanceolate escutcheon extends
from below beaks to posterior angle, bounded by an in-
conspicuous ridge (Pl. 15, figs. 8, 16). Postumbonal slope
slightly convex, becomes subalate posteriorly.
In dorsal view, greatest gibbosity is posterior to beaks
but anterior to mid-length of valves. Valves taper evenly to
posterior margin.
Edentulous; anteriorly, valves become thickened to form
base for muscle attachment; thickened area sharply defined,
limited to area anterior to beaks (PI. 15, fig. 17). Within
thickened portion of valve two well-defined muscle scars
present; heart-shaped, deeply incised, anterior adductor
situated near valve extremity, elongate-oval accessory
muscle scar present immediately adjacent to anterodorsal
margin between beaks and anterior adductor scar (PI. 15,
wea, 7, IHD) «
Surface ornamentation of irregular concentric undula-
tions of valve. On postumbonal slope approximately four
weakly developed radiating ribs present on most specimens.
These ribs are not uncommonly reflected internally.
Remarks.—In_ general form and appearance Sanguino-
lites? herricki closely approaches the species here assigned
to Parallelodon (Cosmetodon). It may be distinguished
from these by absence of the distinct dentition character-
istic of that genus, by the presence of a strong umbonal
ridge, and by the occurrence of a distinct accessory muscle
scar immediately above the anterior adductor. The acces-
sory muscle scar of Sanguinolites was emphasized as a
generic character by Williams and Breger who stated (1916,
p. 130) , “Sanguinolites McCoy, 1844 (not De Koninck, 1885
=Sphenotus Hall, Mostly), is like Sedgwickia but very
long drawn out transversely; gaping behind, not in front,
and with a distinct retractor muscle impression above the
strongly marked anterior cicatrix.”
The present species might also, on general form, be
assigned to Modiomorpha. ‘Vhis genus, however, pos-
sesses two cardinal teeth on the left valve and one on the
right valve. No dentition has been found in Sanguinolites?
herricki.
The specimens of Sanguinolites unioniformis figured by
Herrick (1888, vol. 3, pp. 67-68, pl. 9, figs. 5, 7-9) appear
to have been lost. Although Herrick’s figure 7 seems to be
distinct from the present species, his figures 5, 8, and 9
show a good deal of similarity to it. Herrick’s specimens
Sd PALABONTOGRAPHICA
are larger than those found in the Marshall sandstone,
and the two groups of shells can only tentatively be con-
sidered synonymous.
Sanguinolites? herricki is distinguished from Sanguino-
lites? burlingtonensis Worthen (1890, pp. 129-130, pl. 20,
figs. 8, 8a) by the smaller size, less alate posterodorsal mar-
gin, and straight or nearly straight cardinal margin of the
former as opposed to the posteriorly elevated cardinal
margin of Sanguinolites? burlingtonensis.
Edmondia? angusta de Koninck (1885, pp. 50-51, pl. 13,
figs. 6, 7) appears, from De Koninck’s figures, to possess a
lanceolate escutcheon. ‘Phis character, if present, would
indicate that the species does not, in reality, belong to
Edmondia. In certain respects this species is similar to San-
euinolites? herricki. The present species may be distin-
guished by its more anteriorly situated beaks, its relatively
greater height posteriorly, and by the fact that, in dorsal
view, the greatest gibbosity is in a more anterior portion
of the valves.
Types and occurrence.-UMMP, No. 43048, an internal
mold of a right valve from the Marshall sandstone at Hol-
land, Ottawa County, Michigan, is here designated holo-
type of Sanguinolites? herricki. Figured paratypes, UMMP,
Nos. 43050, 43052, 43053 are also from Holland. Figured
paratypes, UMMP, Nos. 31717 and 37351, respectively a
right and left valve, are from Battle Creek, Calhoun County,
Michigan. Unfigured paratypes, UMMP, Nos. 43049, 43051,
13054 and 45055 are all from Holland, Michigan.
Sanguinolites? herricki occurs in the Marshall sandstone
of Ottawa and Calhoun Counties, Michigan, and has prob-
ably been recorded by Herrick (1888, vol. 3, p. 68) from
“Shale 4 feet below Conel. I, at ‘Dugway,’ Granville, Ohio.”
Sanguinolites unioniformis Winchell
Plate 11, figures 10-33
Sanguinolites unioniformis Winchell, 1862, pp. 414-415. Non Sanguino-
lites unioniformis Herrick, 1888, vol. 3, pp. 67-68, pl. 9, figs. 5, 7-9
(=Sanguinolites herricki in part).
Original description.— (Winchell, 1862, pp. 414-415).
Shell small, compressed, tranversely ellipsoidal, with subterminal
beaks. Hinge line straight, a little shorter than the shell at both ex-
tremities; hinge consisting only of a long, sharp, laminar tooth be-
hind the beak. Anal margin obliquely subtruncate, as also the supero-
buceal region; ventral border very slightly curved. Beaks subter-
minal, flat, not projecting beyond the dorsal line. Anterior muscular
impression circular, deep, behind which is a clavicular process ex-
tending from beneath the beaks, at right angles with the dorsal line,
half way across the valve. Cast nearly smooth, but marked by a few
concentric undulations. Shell very thin, marked simply with fine in-
cremental lines.
Length © 84 (100); height -39 (46); convexity of one valve ° 11
(13); projection of anterior extremity beyond beaks © 12 (14).
Locality —Sec. 29 Moscow, Hillsdale county.
Revised description —Equivalved, height approximately
1/4 of length, dorsal and ventral margins subparallel; dor-
AMERICANA
(V, 35)
sal border straight or slightly curved, declining posteriorly.
Ventral margin straight or slightly sinuous; posterior end
nearly evenly rounded but more gently curved above than
below; posterior valve extremity situated below mid-height
of valve; anteriorly, ventral margin curved regularly up-
ward to valve extremity; anterodorsal margin concave.
Prosogyrate, beaks situated approximately 1/5 to 1/6 of
shell length from anterior extremity, not rising above dorsal
margin. Umbonal ridge broad and indistinct. Weak, broad
sulcus extends from beaks posteroventrally, accounting for
slight sinuosity of ventral margin. Deep, sharply defined,
narrow, lanceolate escutcheon extends posteriorly from
beaks (PI. 11, fig. 33). Margin of escutcheon distinctly
marked by overhang of normal shell material above the
escutcheon area (PI. 11, figs. 10, 23, 33).
Anterior adductor muscle scar prominent, subtriangular,
deep, situated subterminally, adjacent to the concave an-
terodorsal margin (PI. 11, figs. 15, 15, 17, 19, 21). Behind
anterior adductor is a strong, narrow ridge extending ven-
trally from dorsal margin to the pallial line, which is entire
(PI. 11, fig. 21). Small elongate retractor muscle scar pres-
ent immediately adjacent to anterodorsal margin between
anterior adductor scar and beaks. Posterior adductor not
observed.
Probably edentulous. Hinge margin thickened below
beaks and escutcheon but neither teeth nor sockets are ap-
parent (PIS lil; ties: 10.23).
Surface sculpture of somewhat irregular concentric undu-
Ss
lations and fine, closely and regularly spaced, concentric
striae (Pl. 11, figs. 28, 31). Surface sculpture not commonly
reflected internally.
Remarks.—Sanguinolites unioniformis is characterized by
its prominent anterior adductor scar and associated ridge,
elongate retractor scar, the absence of a strong umbonal
ridge, and by its sharply defined, lanceolate escutcheon.
The present species may be distinguished from Sphenotus
obliquus (Meek), which it approaches in size and general
shape, by the above mentioned characters as well as by the
absence of the linear surface nodes which are present in
S. obliquus.
There is close resemblance between Sanguinolites unioni-
formis and Sphenotus acolus (Hall). This is particularly
marked if comparisons are made between Meek’s illustra-
tions (1875, pl. 16, figs. la, b, c) and those of the present
paper, notably Plate 11, figures 29, 30, 31. Of his illustra-
tions Meek said (1875, p. 308), “Our figures and descrip-
tions are from some of the original typical specimens of
the species, or at least that were labeled and returned to Dr.
Newberry, with the name attached, by the author of the
MIUSSISSIPPIAN DIMYARIAN PELEGYPODS: DRISCOLI 85
species.” The writer has examined one of the specimens of
Sphenotus acolus figured by Hall (1885, pl. 66, figs. 55, 35) .
It differs from the present species in possessing a much
stronger umbonal ridge, a more truncate posterior margin,
more gibbose form, and in lacking the sharply defined
escutcheonal borders of Sanguinolites unioniformis. If
Meek’s specimens and the one figured by Hall are conspe-
cific, it follows that Meek’s specimens are not conspecific
with the present species. Further work will be necessary to
resolve the relationships of S. unioniformis and Sphenotus
aeolus.
The hinge of both valves of Sanguinolites unioniformis
is illustrated in Plate 11, figures 10, 23. These lateral views
clearly illustrate normal shell material overhanging the
escutcheonal area. In lateral view the floor of the escutch-
eon, which is somewhat thickened, can be mistaken for a
long lateral tooth. The writer believes this species to be
edentulous.
Types and occurrence.—Ywo of Winchell’s primary types
of Sanguinolites unioniformis have been examined by the
writer. These were considered syntypes by Winchell.
UMMP. No. 26899 is here designated lectotype and No.
44166 paralectotype. Both of these specimens are from the
Marshall sandstone at Moscow, Hillsdale County, Michigan.
Three other specimens from Marshall, Michigan, UMMP.
Nos. 44167-44169, are considered as hypotypes. UMMP.
Nos. 44170-44172, three specimens from Battle Creek,
Michigan, are also regarded as hypotypes.
Sanguinolites unioniformis occurs in the Marshall sand-
stone of Hillsdale and Calhoun Counties, Michigan. A
closely related, or possibly identical, form has been de-
scribed by Meek (1875, pp. 307-308, pl. 16, figs. la, b, c)
from the Waverly group in Medina County, and at Newark,
Ohio.
Genus SPHENOTUS Hall, 1885
Sphenotus Hall, 1885, p. 33; Beushausen, 1895, pp. 213-214; McAlester,
1962, pp. 61, 62.
Type species—By subsequent designation, Sanguinolites
arcaeformis Hall and Whitfield (Miller, 1889, p. 513).
Remarks.—Hind (1900, p. 363) said that “The genus
Sphenotus, Hall, appears to me to be unnecessary, as the
general characters of the genus are identical with Sanguino-
lites.” However, as defined by Hind, the genus Sanguino-
lites includes a group of shells with widely differing char-
acteristics. Hall (1885, p. 53) stated that the ligament of
Sphenotus is “.
cardinal line.” This character, clearly present in the well-
preserved specimens of Sphenotus obliqiias which ave dis-
contained in a slender groove along the
cussed below, in association with a well-defined umbonal
ridge and the absence of a retractor muscle scar between the
beak and anterior adductor scar, is considered to be suffi-
ciently definitive for generic differentiation. It is note-
worthy that the species discussed below does not possess a
median ridge on the postumbonal slope, a character com-
monly present in typical species of the genus.
Sphenotus obliquus (Meek)
Plate 12, figures 1-19
Sanguinolites? obliquus Meek, 1871, pp. 69-70; 1875, pp. 306-307, pl.
16, figs. 2a, b.
Sanguinolites obliquus Herrick, 1888, vol. 3, p. 70.
?Sanguinolites naiadiformis Winchell, 1871, p. 255: Herrick, 1888
vole3; pri pl. 95 tips sic pla 4ation 2) (Co)icmple 2setio mls:
Sphenotus obliquus Hyde, 1953, pp. 309-310, pl. 39, figs. 4, 5.
Revised description —Equivalved, inequilateral, elongate,
subtrapezoidal bivalve; length approximately 2.5 times
height; beaks approximately 1/8 of total length from an-
terior extremity; dorsal margin straight or slightly arched,
abruptly curved into posterior margin, which is subtruncate
above and evenly rounded below; ventral margin straight
or slightly sinuous, curving evenly into anterior margin;
border markedly concave between beaks and anterior ex-
tremity of valves.
Beaks depressed, incurved, not rising aboye dorsal mar-
gin. Valves moderately convex, marked by prominent,
abruptly rounded, umbonal ridge extending from beak to
posteroventral extremity. Broad shallow sulcus extends
from umbonal region to ventral margin across central part
of valve below umbonal ridge, giving rise to somewhat sinu-
ous ventral border.
Heart-shaped lunule-like area anterior to beaks. Pos-
teriorly, elongate escutcheon, delineated by distinct border-
ing ridge, extends along dorsal margin (PI. 12, figs. 1, 2,
15). Preserved within the escutcheon on some specimens
is a distinct, narrow, elongate groove extending posteriorly
from the beaks, subparallel to hinge line, reaching ap-
proximately to mid-length of valves (PI. 12, figs. I, 2, 6).
This groove apparently served for ligamental attachment.
Below the escutcheon, valve margin is thickened, giving rise
to an escutcheon-like depression in natural internal molds
(RUS 2 ational)
Anterior adductor muscle scar preserved on some speci-
mens, situated subterminally, below lunule-like area (PI.
12, figs. 7, 9), delineated by narrow ridges, which appear
as grooves on internal molds, anterior and posterior to scar.
Posterior adductor not observed. Dentition not observed.
Surface ornamentation complex, observed on a single
specimen, consists of fine, irregular, concentric growth
striae and more prominent, inregular, concentric undula-
tions. The latter are usually preserved on internal molds.
86 PALAEONTOGRAPHIC
Four distinct crenulated ridges extend radially across post-
umbonal slope (Pl. 12, fig. 5). The most ventral of these
lies on the umbonal ridge, the other three being evenly
spaced between the umbonal ridge and dorsal margin. Be-
tween these crenulated ridges the fine, concentric growth
striae are nearly straight and regularly arranged.
Small distinct nodes present on posterior part of shell
(Pl. 12, figs. 4, 5). These are arranged in distinct radiating
lines below umbonal ridge and appear to become less
strongly developed anteriorly. Between crenulated ridge on
umbonal ridge and the next higher crenulated ridge, the
nodes are irregularly arranged. On more dorsal parts of
valve, nodes are absent. Along ventral margin on posterior
part of valve, extremely fine ridges are present connecting
nodes of one radiating line with one or more nodes in
(Pl. 12, fig. 4). These are tenta-
tively considered to be of organic origin.
adjacent radiating lines
Remarks.—Sphenotus obliquus is similar in certain re-
spects to the form described as Sanguinolites tricostatus
(Portlock) by De Koninck (1885, pp. 84-85, pl. 15, figs.
14, 15). The size, general shape, ridges on the postumbonal
slope, and surface ornamentation of nodes and concentric
sculpture are points of correspondence. Sphenotus obliquus
may be distinguished by possessing four, rather than three.
ridges on the postumbonal slope, and the fact that the
ridges appear to be more weakly developed. The nodes on
Sphenotus obliquus are not due to a reticulated pattern as
they are in Sphenotus tricostatus and the anterior extremity
of S. tricostatus appears from De Koninck’s figures to be
more evenly rounded than it is in the present species.
In 1871 Winchell (p. 255) described the species San-
guinolites naiadiformis. The only specimen extant (UMMP,
No. 26747) from Hillsdale, Michigan, has not previously
been figured (PI. 12, figs. 18, 19 of the present paper) . This
specimen, though poorly preserved, is less convex and
possesses a less prominent umbonal ridge than in typical
members of Sphenotus obliquus. These differences are
thought to be due to compaction. No clearly definitive char-
acters are present by which S. naiadiformis Winchell may
be differentiated from Sphenotus obliquus (Meek). They
are here tentatively considered to be conspecific.
It seems likely that Herrick (1888, vol. 3, p. 71, pl. 4, fig.
2; pl. 9, fig. 3; 1893, pl. 23, fig. 18) was dealing with the
present species. The specimen figured by him (1888, vol. 3,
pl. 9, fig. 3) shows a similar general shape. Furthermore,
his 1893 illustration (pl. 25, fig. 18) shows faint radiating
lines on the postumbonal slope. These might well corres-
pond to the radiating, crenulated ridges found on the pres-
ent species. Below the umbonal ridge in this figure, the
‘A AMERICANA
(V, 35)
radiating lines shown by Herrick might be interpreted as
representing the radiating series of nodes of the present
species, particularly since they seem to disappear anteriorly.
There is some similarity between Sphenotus obliquus
and Sanguinolites websterensis Weller (1899, pp. 36-37, pl.
3, fig. 7). Hyde (1953, pp. 311-312) pointed out that S.
websterensis possesses three inconspicuous ridges above the
umbonal ridge on the postumbonal slope as well as radi-
ating lines of tubercles which are most prominent on the
posterior two-thirds of the shell. Sphenotus obliquus may be
distinguished by its nearly parallel dorsal and ventral bor-
ders as well as by the more abruptly truncated posterior
margin. In Sanguinolites websterensis the shell is markedly
higher and the posteroventral border more evenly rounded.
Furthermore, the anterior border of S. websterensis does not
appear to exhibit the marked concavity between beaks and
extremity which marks Sphenotus obliquus. The radiating
nodes of Sanguinolites websterensis are demonstrated by
Hyde (1953, pl. 43, fig. 12) to cover most of the postum-
bonal slope. This is not true in Sphenotus obliquus, in
which radiating nodes are largely limited to the region be-
low the umbonal ridge. Despite these differences there can
be little doubt that these two species are rather closely
related to one another.
Hyde (1953, p. 312) distinguished S. websterensis from
Sanguinolites oblongus Hind (1900, pp. 396-398, pl. 43,
figs. 6, 7) only by the latter’s parallel dorsal and ventral
borders. S. oblongus may be distinguished from the pres-
ent species by its more rounded and less truncate posterior
border and by the absence of any sharply concave area be-
tween beaks and anterior margin.
Sphenotus obliquus is perhaps most closely related to
Sphenotus acolus described by Hall from the W averly group
of Licking County, Ohio. The writer has examined one of
the specimens illustrated by Hall (1885, pl. 66, figs. 33,
35) from this locality, as well as Hyde’s (1953, pl. 39, fig.
4) specimen of S. obliquus, refigured on Plate 12, figure 17,
of the present paper. Hyde (1953, pp. 307-310) emphasized
that, in Ohio, specimens of S. aeolus and S. obliquus are
commonly crushed, leading to difficulty in differentiation
of the two species.
The Marshall sandstone specimens are commonly not
crushed. They are identical with the uncrushed specimen
of S. obliquus figured by Hyde (PI. 12, fig. 17 of present
paper) but differ significantly from Hall's specimen of S.
aeolus.
Hyde (1953, p. 309) stated that Sphenotus obliquus is
“Like S. acolus Hall, except that the shell is slightly longer,
and the dorsal margin is more nearly parallel to the ventral
NMIISSISSIPPIAN DIMYARTAN
margin and not declining. Beaks a little nearer the anterio1
end. Umbonal ridge a little more prominent and postum-
bonal slope broader.”
Comparison of Hall’s type specimen of S. aeolus with
Marshall sandstone specimens of S. obliquus indicates that
S. obliquus may, as suggested by Hyde, be distinguished by
its greater relative length, its nearly parallel dorsal and
ventral margins, and particularly by its broader postum-
bonal slope. The writer’s observations, however, indicate
that umbonal ridges in the two species are of approximately
equal strength, and that the beaks of S. obliquus, contrary
to the statements of Hyde (1953, p. 309) and Meek (1875,
p. 307), are located more posteriorly than in S. acolus.
Types and occurrence.—The primary type material of
Sphenotus obliquus (Meek) is reported from the upper
part of the Waverly group at Rushville and Newark, Ohio.
The writer considers hypotypes the following specimens
from the Marshall sandstone: UMMP, Nos. 44071-44077,
43059. Nos. 44071 and 44072 are from Battle Creek, Michi-
gan. Nos. 44073, 44074, 44077 are Marshall,
Calhoun County, Michigan; Nos. 44075 and 44076 (unfig-
ured) are from Hillsdale County, Michigan; and No. 43059
(unfigured) is a drift specimen from Grass Lake, Jackson
County, Michigan.
The specimen described by Winchell (1871, p. 2
Hillsdale,
(UMMP, No. 26747) is here considered as probably syn-
onymous with the above mentioned specimens but, because
it is poorly preserved and probably crushed, it is not used
as a basis for the revised description of Sphenotus obliquus
(Meek) .
In summary, Sphenotus obliquus (Meek) occurs in the
Allensville member of the Logan formation near Newark
and at Rushville, Ohio, as well as at various localities in
the Marshall sandstone of Calhoun and Hillsdale Counties,
Michigan.
and from
e
95) as
Sanguinolites naiadiformis from Michigan,
Genus SOLENOMORPHA Cockerell, 1903
Solenopsis McCoy, 1862, p. 47 (non Solenopsis Westwood, 1841, p.
86, which is a common genus of ant); Meek, 1872, pp. 223-224;
Girty, 1910, p. 223.
Solenomorpha Cockerell, 1903, p. 559; 1915, p. 84; Hind, 1904, pp.
157-158; Williams and Breger, 1916, p. 250. (See Hind, 1904, for
other references) ; Elias, 1957, pp. 738-740.
Type species—By monotypy, Solenomorpha minor (Mc-
Coy) , 1862, pp. 47, 239, 245, pl. 8, fig. 2.
(1910, p. 223) included Solenopsis
nitida Girty in McCoy’s genus apparently not aware that
the name Solenopsis McCoy was preoccupied. Concerning
the morphology of S. nitida, Girty said (p. 223), “Anterior
Remarks.—Girty
end apparently gaping, especially above.” This is significant
PELECYPODS: DRISCOLI 87
because it broadens McCoy’s original definition of the genus
Solenopsis in which he said (p. 47) that Solenopsis differs
from Solen in the “rounded and closed anterior end.”
Elias (1957, pp. 738-740) may well be correct in lowering
Solenomorpha to subgeneric rank under the genus Solen.
Certainly he demonstrated (and the present paper substan-
tiates) a similarity of dentition in the two “genera.” I
tentatively maintain Solenomorpha at the generic level for
the present because an equal height throughout the length
of the shell seems characteristic of Recent forms assigned
to Solen whereas a decrease in height posteriorly appears
to be characteristic of Solenomorpha.
Solenomorpha scalpriformis (Winchell)
Plate 13, figures 15-23
Solen scalpriformis Winchell, 1862, p. 422.
Winchell (iz Safford, 1869, p. 445) ;
chell, 1871, p. 256.
Non Solen scalpriformis
nec Solen scalpriformis Win-
Original description.— (Winchell, 1862, p. 422).
Shell of moderate size, having the hinge line straight, and the
ventral regularly curved, and so situated that its chord forms pos-
teriorly, an angle of about 5° with the dorsal margin; extremities
abruptly rounded—the anterior one regularly, the posterior trun-
cately. Valves with a slight constriction beneath the subterminal
beaks, which correspond to a strong ridge within, fading away at
about half the distance from the dorsal to the ventral margin. Valves
but moderately inflated, flatter behind, and a little drawn together
anteriorly. Exterior surface marked by incremental lines nearly con-
centric with the pallial border.
Length of shell 2°05 (100); projection of anterior extremity beyond
the breaks ‘11 (5); greatest width of shell (one-third its length from
forward end) ‘56 (27); width at two-thirds the shell-length from
forward end 48 (23), whence it narrows rapidly.
Localities —Marshall and Moscow, abundantly. Also, near Napoleon.
A well marked variation in form has been observed in many speci-
mens, having a straight ventral border and more uniform width.
Revised description.—The following description is based
on the lectotype, six paralectotypes, and four hypotypes.
Shell solenoid, equivalved, inequilateral, length approxi-
mately four times height. Dorsal margin straight and slight-
ly shorter than the ventral margin. Ventral margin regu-
larly curved, greatest height being anterior to the mid-
length of shell.
leneth of truncation being less than 1/2 valve height. Beaks
low, subterminal, and ill-defined. Umbonal ridge poorly
Posterior margin diagonally truncate,
defined.
Anterior adductor muscle scar oval, striate, and located
in umbonal part of valves (PI. 13, figs. 18, 20). Striae of
adductor scar anastomosing, radiating outward from beak.
Posterior adductor scar not preserved.
Dentition consists of a single platelike cardinal near the
anterodorsal angle of each valve (PI. 13, figs. 19, 20).
Cardinal tooth supported ventrally by a prominent ridge
originating approximately 1/1 of the shell height from the
dorsal margin, and fusing with the anterior extremity of
88 PALAKONTOGRAPHICA AMERICANA (V, 35)
the cardinal tooth. Angle between dorsal margin and this
ridge is approximately 115°.
Thin shell marked by weak, irregular concentric ridges
parallel to ventral and posterior margins. Ridges more
pronounced near these margins and particularly so parallel
to the ventral margin, weaker on the younger parts of the
shell and parallel to the posterior margin, reflected inter-
nally (Pl. 13, figs. 18, 22, 23). Fine, regular, concentric
striae present on exterior of valves.
Remarks.—The cardinal teeth described above apparently
do not interlock. The tooth of one valve appears to act as
an articulating surface against which the tooth of the other
valve moves.
Geinitz (1866, p. 25, pl. 2, fig. 7) described a new
species of lamellibranch, Clidophorus solenoides Geinitz
from Nebraska City, Nebraska. Subsequently Meek (1872,
pp. 223-224, pl. 10, fig. 3) and Keyes (1894, p. 130) re-
described the species as Solenopsis solenoides (Geinitz) .
The enlarged figures published by both Geinitz and Meek
show, in many respects, marked similarity to Winchell’s
specimens of Solenomorpha scalpriformis. Comparison. of
Meek’s’ hypotypes of Solenomorpha solenoides (Geinitz)
(USNM, No. 6488) with the specimens of Solenomorpha
scalpriformis indicates that their anterior margins differ
somewhat in outline, that of S. scalpriformis being truncate
or subtruncate and that of S. solenoides more rounded.
The most striking difference between the two species is
size. The mean length of ten of Meek’s hypotypes of S. sole-
noides (Geinitz) is 14.3 mm, whereas the mean length of
Winchell’s specimens of S. scalpriformis is 48.1 mm.
Types and occurrence.—The material upon which Alex-
ander Winchell based Solen scalpriformis consists of seven
syntypes. UMMP, No. 268914, a right valve, is here desig-
nated lectotype. Paralectotypes, UMMP, No. 43056, a right
valve, No. 43057, a left valve, and No. 36811, a right valve,
are well preserved and are figured in this paper. Unfigured
paralectotypes, UMMP, Nos. 21895A, B, and C, are frag-
mentary and poorly preserved right valves. Winchell re-
ported that his specimens were collected at Marshall, Mos-
cow, and near Napoleon, Michigan, but only the lectotype
and six paralectotypes from Marshall, Michigan, (Winchell
Loc. No. 326) are still present in the collections; the others
are apparently lost. Four hypotypes from Marshall, Michi-
gan, have been used by the writer in the revised descrip-
tion. Winchell collected these specimens, but the date of
collection is unknown. They are UMMP, Nos. 37311, 37313-
37315.
Solenomorpha dorsocurva, sp. nov.
Plate 13, figures 24-26
Solen scalpriformis var. Winchell, 1862, p. 422.
Original description —[See Solenomorpha scalpriformis
(Winchell) above].
A well marked variation in form has been observed in many speci-
mens, having a straight ventral border and more uniform width.
Revised description.—The following description is based
on the single remaining specimen in the Winchell collec-
tion which he considered to be a variation in form of Solen
scalpriformis.
Shell solenoid; length approximately four times height.
Dorsal margin slightly curved, concave upward, and shorter
than ventral margin. Ventral margin regularly curved (de-
viation from regular curvature seen in Plate 13, figure 25,
probably due to distortion of specimen). Greatest height
anterior to mid-length of shell. Posterior margin truncate,
truncate edge being only slightly shorter than maximum
shell height and forming a posterodorsal angle of approxi-
mately 120°. Abruptly rounded posteroventrally, Anterior
margin rounded.
Shell narrow. Valves thickened anterior to beaks, slightly
gaping anteriorly and posteriorly. Beaks low, subterminal,
and ill-defined. Umbonal ridge absent.
Muscle scars not preserved.
Dentition poorly preserved. A single platelike cardinal
near anterodorsal angle of each valve, supported ventrally
by a small short ridge originating in the dorsal part of the
thickened anterior portion of the valve and fusing dorsally
with the anterior extremity of the platelike cardinal.
Interior of valve marked by growth lines parallel to the
ventral margin, these being weak in younger portion of
valve but prominent near valve margin.
Remarks.—Solenomorpha dorsocurva shows certain char-
acters of both Solenomorpha scalpriformis (Winchell) and
Palacosolen quadrangularis (Winchell). The dentition,
curved ventral margin, and subterminal beaks indicate
affinity with Solenomorpha scalpriformis. The long trun-
cated posterior margin. is similar to that of Palaeosolen
quadrangularis. S. dorsocurva is differentiated from both
of these by its curved dorsal margin which is slightly con-
cave upward. Winchell (1862, p. 422) pointed out that in
S. scalpriformis the chord of the ventral margin is so
situated as to form posteriorly an angle of about 5° with
the dorsal margin. In S. dorsocurva a similar chord is
approximately parallel to the dorsal margin. The cardinal
teeth of Solenomorpha dorsocurva are thought to articu-
late in a manner similar to that of S. scalpriformis (see
above) .
Solenomorpha dorsocurva conforms in many respects to
the original description of Sanguimolites (McCoy, 1862,
pp. 47-48), but redescription of Sanguinolites by Hind
MUSSISSIPPIAN DIMYARIAN
TABLE 1.—ILLUSTRATION OF OVERLAP OF
(1900, pp. 261-366) clarifies the differences. Sanguinolites
commonly has its greatest height in the posterior portion of
the valves and possesses an edentulous hinge in most or
all species, but Solenomorpha dorsocurva has neither of
these characters.
Types and occurrence.—A single specimen (UMMP, No.
36812) a left valve from the Marshall sandstone at Mar-
shall, Michigan, is here designated holotype of Solenomor-
pha dorsocurva. This is the only representative of the spe-
cies still preserved in the Winchell collection, but Win-
chell apparently possessed a number of other specimens
prior to his 1862 publication. These have been subsequently
lost.
Genus PALAEOSOLEN Hall, 1885
Palaeosolem Hall, 1885, p. 46; Beushausen, 1895, pp. 222-223; Wil-
liams and Breger, 1916, pp. 249-250; McLearn, 1924, p. 139.
Type species.—By original designation Palacosolen sili-
quoideus Hall, 1885, p. 483, pl. 78, fig. 53.
Remarks.—Palacosolen was proposed as a subgenus of
Solen by Hall (1885, p. 46), who designated the type spe-
cies. Beushausen (1895, pp. 222-223) and later workers
have considered Palacosolen to be of generic rank.
The height/length ratios in Solen and Palacosolen are
commonly designated in morphologic descriptions. A study
of 13 species of Recent Solen and six species of Paleozoic
Palacosolen indicates that this ratio is of litthe value in
distinguishing the two genera and that height,/ length ratios
PELECYPODS: DRISCOLI 89
HEIGHT/LENGTH RATIOS IN SPECIES OF SOLEN AND PALAEOSOLEN.
haIGH]T/LENGTH
Palaeosolen minutus
Palaeosolen quadrangularis
Palaeosolen belgicus
Palaeosolen siliquoideus
solen brevis
solen ambiguus
Palaeosolen occidentalis
solen lefumens
sollen abbreviatus
solen grandis
pollen Krausenstenii
Omen ramimnaacdealkent
Palaeosolen chapmani
solen alfredensis
solen gouldi
solen vaginus
Solen corneus
solen siliquus
of individual species commonly overlap one another. Table
| summarizes the results of the measurements which were
made. Baker (1943) and Weymouth, McMillin and Rich
(1951) discussed growth in the razor clam, Siliqua patula.
The latter authors concluded that length of shell was
largely related to latitude, with shells reaching greater
leneths in northern than in southern latitudes.
Palaeosolen quadrangularis (Winchell)
Plate 13, figures 1-11
Solen quadrangularis Winchell, 1862, p. 422; 1871, p. 256.
Palacosolen quadrangularis Hyde, 1953, pl. 44, fig. 7 (no description,
specimen lost).
Original description.— (Winchell, 1862, p. 422).
Shell of medium size, quadrangular; hinge margin straight, some-
what shorter than the ventral margin, which is also straight through
the greater part of its length, but is abruptly rounded upwards an-
teriorly, and a little more gradually rounded posteriorly. Beaks
terminal; anterior extremity of shell transversely truncated, posterior
obliquely so. Valves rather tumid anteriorly, becoming less so pos-
teriorly; not at all contracted toward the gaping extremities. A
constriction appears close to the anterior extremity, which corresponds
to a ridge within, narrow and sharp near the beak, but becoming
broad and depressed towards the opposite margin. Surface marked
by distinct lines of growth running parallel with the ventral and
posterior margins.
Greatest length 2:0 (100); width ©66 (33); posterior truncation
forming with hinge-line an angle of about 64°.
Locality —Marshall.
Revised description —The following description is based
on the lectotype, one paralectotype, and ten hypotypes.
Shell solenoid, equivalved, inequilateral, length approxi-
90) PALAEKONTOGRAPHICA
mately three times height. Ventral and dorsal margins
parallel. Dorsal margin straight and slightly shorter than
ventral margin. Ventral margin straight or slightly sig-
moidal. Posterior margin diagonally truncate, forming a
posterodorsal angle of approximately 105°. Ventral margin
abruptly rounded posteriorly. Anterior margin subtruncate,
the anteroventral portion curving into the ventral margin.
Thin-shelled, subcylindrical, valves regularly convex.
Beaks terminal, low, ill-defined. Weakly developed um-
bonal ridge with or without extremely shallow, ill-defined,
diagonal groove, which does not reach the posterior margin
of valves. Valves not contracted posteriorly, slightly con-
tracted anteriorly. Near anterior margin shell thickens and
partially constricts anterior gape of valves (PI. 13, figs. 1, 3,
4)
Anterior adductor muscle scar oval, striate, and located
in umbonal part of valves (PI. 13, fig. 2). Fine striae of
adductor scar radiate outward from beak. Posterior ad-
ductor scar not preserved.
Dentition consists of a single platelike cardinal tooth
near the anterodorsal angle of each valve. The cardinal
tooth of each valve is supported ventrally by a ridge orig-
inating in the anteriorly thickened portion of the valve
(Pl. 13, figs. 1, 2, 8). This ridge first appears about 1/4 of
shell height from the dorsal margin and becomes more
pronounced dorsally until it fuses with the anterior ex-
tremity of the cardinal tooth. Angle between dorsal margin
and supporting ridge 95° to 100°.
Internal and external surface marked by weak concentric
sculpture parallel to the ventral and posterior margins, the
former being more pronounced. Fine striae parallel to mar-
gins developed externally (Pl. 13, fig. 10).
Remarks.—Palacosolen quadrangularis is characterized
by its single platelike cardinal tooth near the anterodorsal
angle of each valve and by the supporting ridge of this
tooth, by the abrupt diagonal truncation of the posterior
margin of the valves, the parallel ventral and dorsal mar-
gins, the general outline, and finally, by the distinct thick-
ening in the anterior part of each valve.
Hall (1885, p. xlvi) in defining the genus Palacosolen
said, “Umbonal slope prominent and extending toward the
postbasal extremity.’ Palaeosolen quadrangularis does not
possess a prominent ridge; nor do the following species
included by other workers in the genus: Palaecosolen occi-
dentalis Miller and Gurley, P. antigonishensis McLearn,
P. amu McLearn, P. costatus Sandberger and Sandberger.
Types and occurrence.—The material upon which Win-
chell based Palacosolen quadrangiularis Consists of two syn-
types. One, a left valve, UMMP, No. 26893A, is here des-
AMERICANA (V, 35)
ignated lectotype and the other, a right valve, UMMP, No.
26893B, is regarded as a paralectotype. Winchell’s syntypes
were collected from the Marshall sandstone at Marshall,
Michigan.
In 1863 Winchell collected a number of specimens of P.
quadrangularis at Battle Creek, Michigan. Hypotype,
UMMP, No. 34838, is from this collection. Nine other
specimens, for which the date of collection is unknown, are
considered as hypotypes. UMMP, Nos. 57298, 37306, 37307,
and 36809 are from Battle Creek, Michigan. UMMP, Nos,
37300, 36826, 36827, and 37321 are from Marshall, Michi-
gan.
In summary, Palacosolen quadrangularis occurs in the
Marshall sandstone of southern Michigan and is present, as
indicated by Hyde (1953, pl. 44, fig. 7) in the Waverly
group of Ohio.
Palaeosolen frontisocurvus, sp. nov.
Plate 13, figures 12-14
Description.—The following description is based on a
single left valve.
Shell solenoid, probably equivalved, inequilateral, length
approximately three times the height. Ventral and dorsal
margins rectilinear and subparallel, diverging slightly pos-
teriorly. Posterior margin diagonally subtruncate, form-
ing a posterodorsal angle of approximately 105°. Anterior
margin rounded, the anteroyentral portion curving evenly
into ventral margin (PI. 13, fig. 13).
Thin-shelled, subcylindrical, valves regularly convex.
Beaks subterminal anteriorly, low and ill-defined. Umbonal
ridge not apparent. Valves slightly contracted anteriorly.
Anterior adductor scar striate, located in umbonal part of
valve. Fine striae of muscle scar radiate posteroventrally
from umbonal region. Posterior adductor scar not pre-
served.
Weak radial sculpture on interior of valves originating
in umbonal region diverges over posterior portion of
valve (Pl. 13, fig. 13). External surface smooth except for
fine, regular striae parallel to margins (PI. 13, fig. 12).
Remarks.—Dentition and anterior shell thickening of
Palacosolen frontisocurvus is probably similar to that of
P. quadrangularis. The single valve examined does not
allow certainty on these points.
Palacosolen frontisocurvis is distinguished from P. quad-
rangularis by the gently curved anteroventval margin of
the former as opposed to the truncate anterior margin of
the latter. The weak internal radial sculpture of P. fron-
lisocurvus is not found in P. quadrangularis, the latter
species possessing, at most, a single weak groove along the
|
|
MIssISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLT 9]
-umbonal ridge. External striae on P. frontisocurvus appear
to be more regular than those of P. quadrangularis.
The name frontisocurvus designates the curved nature
of the anterior margin.
Types and occurrence.—The single left valve, holotype,
~UMMP, No. 37302, upon which this species is based was
collected by Alexander Winchell from the Marshall sand-
stone at Battle Creek, Calhoun County, Michigan. The
date of collection is unknown.
FAMILY GRAMMYSIIDAE
Genus GRAMMYSIA de Verneuil, 1847
Grammysia de Verneuil, 1847, p. 696; Williams and Breger, 1916, pp.
128-132; Williams, 1943, pp. 92-94 (See Williams and Breger, 1916,
for other references).
Type species.—By original designation Grammysia bisul-
cata (Conrad) —Grammysia hamiltonensis de Verneuil
(see Williams and Breger, 1916, pp. 128-129) .
Remarks.—Hoernes_ (1884, p. 242) first defined the
family Grammysiidae. Most writers, Whidborne (1896, p.
74) being a notable exception, have erroneously indicated
that Fischer (1887, p. 1173) was the familial author.
Hoernes’ original definition (p. 242) may be translated as
follows: “We wish to unite under this name [Grammysi-
idae] those Paleozoic forms with a toothless hinge which,
owing to the appearance of their outlines, resemble phola-
domyas and other sinupalliates. However an indentation
of the pallial line could not actually be proved.” Fischer
(1887, p. 1173) emphasized the importance of the entire
pallial line in distinguishing the family Grammysiidae from
related groups, thus clarifying the principal character of the
family. A number of genera lacking pallial sinuses were
thus removed from the family Anatinidae Lamarck (1809) ,
where they previously had been classified by Meek and
Hayden (1865, p. 36) and others.
Williams and Breger (1916) emphasized the importance
of the radial fold and sulcus as definitive characters of the
genus Grammysia and suggested (p. 130) that the genus
should be limited to those grammysioid shells having these
features. They contended (p. 133) that “The genus [Gram-
mysia] is unknown in the Carboniferous. All the American
Carboniferous ‘Grammysias’ listed by Weller are not only
without the radial fold and sulcus or any strictly corres-
ponding structure, but most of the species are gaping pos-
teriorly. (See, for instance, ‘Grammysia’ hannibalensis as
figured by Miller, also ‘Grammysia’ famelica Herrick) .
These will have to be included in the Leptodomus-Sedg-
wickia-Sanguinolites group.” The writer would point out
that although Grammysia famelica Herrick (1888, pp. 35-
36, pl. 6, fig. 5), Grammysia hannibalensis as figured by
Miller (1889, p. 483), and Grammysia ventricosta Meek
(1875, p. 303, pl. 13, figs. 5a, b; pl. 16, figs. 6a, b) appear
to gape posteriorly, Grammysia herricki (Miller) and
Grammysia rhomboides Meek (1875, pp. 302-303, pl. 16,
figs. 7a, b) do not gape. Figures of the other species listed
by Weller (1898, pp. 279-298) do not allow for conclu-
sions concerning the gape of the valves.
In his original definition of the genus Grammysia, De
Verneuil (1847, p. 696) emphasized the importance of the
fold as a generic character. He said (p. 696), “Ce genera,
si bien charactérisé par la c6te médiane qui transverse les
valve, renferme plusieurs espéces, dont l'une a été nommée
Nucula cingulata par M. Hisinger.”
J. S. Williams (1943, p. 93) pointed out that this em-
phasis on the fold as a definitive character has been some-
what modified by later usage, stating (p. 93), “. .. the
fold on a number of species of Grammysia is inconspicuous
and indistinguishable from the slope of the valve. The
general practice has been to include all species otherwise
agreeing with Grammysia in that genus if they have a dis-
tinct sulcus. The fold is such a variable character that it
seems reasonable to allow a certain degree of variation
within the genus, as has been the custom.”
The writer here accepts the conclusion of Williams that
the genus Grammysia extends into the Carboniferous. Wil-
liams (1943, p. 93) pointed out that Grammysia hanni-
balensis (~=Grammysia omaliana discussed below) possesses
a distinct sulcus and that this character, rather than the fold
is of prime importance. It is noteworthy that McAlester
(1962, pp. 59, 60) would include the forms discussed below
in the genus Grammysoidea.
Grammysia omaliana omaliana (de Koninck)
Plate 14, figures 1-9, 13-15, 19-24, 27-39, 42-45
Pholadomya omaliana de Koninck, 1844, pp. 65-66, pl. 5, fig. 4.
Sanguinolites vartabilis McCoy, 1851, pp. 174-175 in part; 1855, p.
508, pl. 3F, figs. 7, 8 in part; Hind, 1900, pp. 379-382, pl. 44, figs. 1,
3-8 (See Hind, 1900, for other references).
Sanguinolites hannibalensis Winchell, 1865, p. 128.
2Allorisma (Sedgwickia) hannibalensis Winchell, 1871, p. 256. Non
Allorisma hannibalensis Shumard, 1855, p. 206, pl. C, fig. 19.
2Grammysia2 hannibalensis Herrick, 1888, vol. 4, pl. 6, fig. 11;
71893, pl. 17, fig. 11.
Grammysia hannibalensis Walcott, 1884, p. 244, in part; ?Herrick,
1888, vol. 3, p. 75, pl. 4, fig. 13; Rowley, 1908, p. 94, pl. 19, figs. 21,
22: Williams, 1931, pp. 134-135, pl. 1, figs. 1-4; 1943, pp. 92-94,
pl. 9, figs. 41-44; Branson, ef al., 1938, p. 34, pl. 23, figs. 4-6. Non
Grammysia hannibalensis Hall, 1885, p. 381, pl. 61, figs. 29, 30, 33;
nec Grammysia hannibalensis Hyde, 1953, p. 305, pl. 38, figs. 1, 2.
Grammysia plena Hall, 1885, pp. 382-383, pl. 61, figs. 31, 32. Non
Grammysia cf. plena Hyde, 1953, p. 306, pl. 38, figs. 12, 13; pl. 39,
fig. 10 (—Grammysia omaliana hydei, sub. sp. nov.).
Allorisma cuyahoga Herrick, 1888, vol. 4, pp. 28-29, pl. 10, fig. 34; ?
1893, pl. 22, fig. 17.
Sanguinolites omalianus Hind, 1900, pp. 372-374, pl. 40, figs. 17-24
(See Hind, 1900, for other references).
Grammysia cuyahoga Hyde, 1953, p. 305, pl. 38, figs. 3-7.
992 PALAEONTOGRAPHICA AMERICANA (V, 35)
Revised description.—The wi iter has examined the speci-
mens of Sanguinolites variabilis McCoy figured by McCoy
in 1855 (pl. 3F, figs. 6, 7, 8), as well as unfigured supple-
mentary material. Specimens of Sanguinolites omalianus
from Thorpe Cloud, Derbyshire, one of Wheelton Hind’s
localities have been examined. Walcott’s specimens from
Nevada and Winchell’s specimens from the Marshall sand-
stone of Michigan have been available to the writer as have
Hall’s specimens of Grammysia plena. Specimens from the
Kinderhook at Burlington, Iowa, which Winchell labeled
Grammysia hannibalensis have been studied. These speci-
mens and the figures referred to in the above synonymy,
have been examined in preparation of the following de-
scription.
Shell tumid, subovate to subquadrangular, umbonal re-
gion gibbous, length | 1/2 to 2 times height, ventral and
dorsal margins subparallel, dorsal margin rectilinear to sub-
rectilinear both anterior and posterior to beaks, the two
straight parts joining below the beaks to form an angle of
from 124° to 145°. Ventral margin straight, gently curved,
or slightly sigmoidal in the central part of the valve, but
broadly and evenly rounded anteriorly and_ posteriorly.
Posterior margin variable, not uncommonly forming an
angle of approximately 135° with that part of the dorsal
margin which is posterior to the beaks. ‘The posterior mar-
ein meets the upward curving ventral margin at the pos-
terior extremity of the umbonal ridge. Valves not gaping.
Anteriorly the ventral margin curves evenly upward to meet
the downward slanting anterior portion of the dorsal mar-
gin, at which point the anterior end is abruptly or gently
rounded.
Umbonal ridge usually prominent, commonly slightly
concave upward in lateral view. Deep elongate escutcheon
bordered by distinct ridge subparellel to hinge line. Be-
tween umbonal ridge and ridge bordering escutcheon
postumbonal slope is variable, typically possessing a con-
cave surface which becomes broader posteriorly as dis-
tance between the two ridges increases to the posterior
margin. In some specimens postumbonal slope is convex
and not uncommonly it possesses weak grooves and ridges
radiating from the umbonal region.
Prosogyrate, prominent beaks placed anteriorly, strongly
incurved over hinge line so that the beaks are situated
below the gibbous umbos and the umbos are in close prox-
imity, Or are in contact with one another.
Lunule deep, prominent, and semiovate, extends from
beaks to junction of dorsal margin with upward curved
anteroventral margin.
A shallow sinus commonly extends from the anterior
part of the umbo posteroventrally to the ventral margin.
It becomes wider ventrally. Typically this sinus is distinct
but, in certain valves, it is less pronounced or nearly ab-
sent. The sinus is a variable characteristic, all gradations
between a very weak sinus and a rather pronounced one
having been observed.
Surface ornamentation universally consists of fine con-
centric striae superimposed on heavy, well-defined, con-
centric ridges. Striae are better developed on the posterior
part of the valve. Ridges are commonly, but not universally,
somewhat more sharply defined on anterior part of valve
where they vary in number as shown in ‘Table 2. The
concentric ridges ventral to the umbonal region and above
the ventral one-third of the valve exhibit a distinctive
character on most specimens. Anterior to the sinus extend-
ing from beak to ventral valve margin the ridges are
generally evenly spaced. Commonly every other one of
these anterior ridges bifurcates on posterior side of sinus,
giving rise to two ridges. Alternate anterior ridges, between
those which bifurcate, extend across the sinus unaffected.
Concentric ridges on the umbonal region and on the ven-
tral one-third of the valve extend across the sinus unaffect-
ed on most specimens. On the ventral portion of the valve
they are much less sharply defined than on the umbonal
region. Although often present this ridge development is
variable. All gradations between many bifurcating ribs
and no bifurcating ribs are present, and it is not unusual
to find some adjacent rather than alternate ribs bifurcating.
Remarks.—Yhere is considerable superficial similarity
between certain species of Grammysia and some members
of the genus Wilkingia. Wilson (1959, pp. 401-404) dis-
cussed the characteristics of the latter sinupalliate form.
The present species is referred to Grammysia largely on
the basis of the entire pallial line reported by Hind (1900)
for Sanguinolites variabilis (p. 380) and Sanguinolites
omalianus (p. 373). The pallial line was not visible in any
of the specimens examined.
The writer grouped, within a single species, a consider-
able number of pelecypods from widely separated locali-
ties which were previously considered specifically distinct.
A reexamination of the characters previously utilized to
distinguish these ‘species’ seems advisable.
Hind (1900, p. 373) noted the similarity between San-
euinolites omalianus (de Koninck) and Sanguinolites vari-
abilis McCoy. He stated (p. 374) that “S. Omalianus be-
longs to that group of the genus which contains S. costel-
latus and S. variabilis, from both of which it differs in im-
portant details. In gibbosity S. Omalianus is less strongly
convex than the former, but more convex than the latter;
MISsSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLI 93
the rugae and sulci are much stronger and fewer than in
both.” The writer examined specimens of S. omalianus
from the Visean Zone D, Thorpe Cloud, Derbyshire, one
of the localities from which Hind’s specimens were col-
lected. McCoy’s figured and unfigured specimens of S. vari-
abilis have also been examined. S. omalianus does, in gen-
eral, appear to be slightly more gibbous than S. variabilis,
but this character is unreliable. A number of specimens of
S. omalianus are less gibbous than specimens of S. variablis.
Examination of the concentric grooves and ridges show that
there is considerable variation in the strength of these fea-
tures within such “species,” but that it is not possible to
separate the two groups on this basis. The number of con-
centric ridges is also variable in each group of shells. Eight
specimens of S. omalianus showed a variation of from 16 to
34 concentric ridges. Eight specimens of 8. variabilis showed
a variation of from 16 to 29 ridges. Table 2 indicates the
variation in number of ridges per centimeter. Whereas both
De Koninck (1885, p. 6) and Hind (1900, p. 374) consid-
ered S. omalianus to possess fewer ridges, the reverse is, in
general, true. This character, however, cannot be utilized
to separate the two groups.
Hind (1900, p. 374) said, “I cannot, however, agree
with De Koninck that Allorisma Hamiltonensis of Shumard
and the Grammysia Hannibalis of Meek are the same
species as the Belgian shell [Sanguinolites omalianus]. 1
have been able to compare specimens and can see no
reason for mistaking the two forms which in my opinion
are distinct. The American shell is much less gibbous, regu-
larly ovate, compressed, and much smaller. The concen-
tric ribs do not bifurcate, and are fewer and larger; the
dorsal slope is much smaller and more compressed; but
there is no doubt that both species belong to the same
genus.” The two specific names above were misspelled by
Hind and should be read as Allorisma hannibalensis and
Grammysia hannibalensis.
It is not certain which specimens of the American species
were examined by Hind. Unfortunately, Shumard’s type
specimens were lost by fire in 1893, and the writer has
not located the specimens described by Meek (1875, pp.
300-301, pl. 16, figs. 5a, b, c) which are presumed to be lost.
The species described by Shumard and Meek are here con-
sidered distinct, the latter being referred to Grammysia
omaliana hydei, but Hind’s comments on the American
shells appear to refer to characters of both species.
‘The writer finds no pronounced difference in gibbosity
between “S. omalianus” and the American specimens he has
examined. It is true that the larger specimens of “S. oma-
lianus” from the Visean D zone, Thorpe Cloud, Derby-
shire, appear to be more gibbous than American specimens,
but this character is not consistent in all specimens of the
“species” and cannot be utilized for differentiation.
Text-figure 4, D, illustrates the height/0.5 width ratio, a
measure of gibbosity. It is evident that although “S. omali-
anus’ contains the most gibbous shells the range of gibbo-
sity overlaps that of a number of American “species.” It
should be noted that gibbosity is a poor criterion for species
differentiation, being subject to change due to compaction
of the sediments.
Text-figure 5, as well as Plate 14, illustrates that outline
is variable in “S. omalianus’” as also in the American
“species.”
Table 2 illustrates that, contrary to Hind’s opinion, the
average size of “S omalianus” is not larger than that of the
American “species.” Although an insufficient number of
specimens have been examined for any meaningful state-
ment on average size, it appears that the Thorpe Cloud
specimens of “S. omalianus” are slightly smaller than most
American “species” here considered. The difference in size
Is not significant.
In the writer's opinion there is no significant difference
in pattern, form, or strength of concentric ridges in the
various “species” here included under Grammysia omaliana
omaliana, Contrary to Hind’s statement, the ribs of all
American “species” included in the above synonymy do
bifurcate. The bifurcation pattern appears to be variable
within all “species,” being striking in certain specimens but
weak or nearly absent in others. The same variation is pres-
ent in the strength of ribbing and, as shown in Table 2, the
number of ribs is variable and overlapping. It is true that
certain specimens of Sanguinolites omalianus have more
ribs per unit of height than any American specimens ex-
amined but, because this character is not consistent, it
cannot be used for specific differentiation.
Variation in the character of the postumbonal slope is
present in all “species,” both American and British, and
neither its size, form, nor compression is considered to be
significant for specific differentiation. Text-figure 5 illus-
trates the variability of the umbonal outline and the out-
line of the posterior margin in a number of the specimens
which were examined. Meek (1875, p. 301) well appreci-
ated the variation in specimens he examined from Ohio,
stating “ this shell varies much in form, as well as in
the size and regularity of its concentric ridges and furrows.
The furrow extending down each valve from the beaks is
generally obsolete or so faintly defined as scarcely to at-
tract attention, though it is quite distinct on some speci-
mens.” Meek’s specimens are here assigned to Grammysia
94 PALAEONTOGRAPHICA AMERICANA (V, 55)
G plena —lowa |] Ames 205 5% 2553) Coldwater fm —Mich
6 hannibalensis — |owa oh Ten G. rostrata — Ohio
S. omalianus — England (Wiech ai Morshall ss.— Mich.
G. honnibalensis — Mo,, (Williams) 6 G. hannibalensis —lowa
Coldwater fm.— Mich r] = G. hannibalensis — Mo., (Williams)
Morsholl ss.— Mich io] G. honnibalensis —Mo., (Branson)
G. hannibalensis — Nevada a G. Cuyahoga — Ohio
G. cuyahogo — Ohio ee) G. hannibalensis — Ohio
Ss. variabilis — England = ae G. plena— jowa
G. rostrata — Ohio et as. ToC Ss. variabilis — England
G. hannibalensis —Mo., (Branson) a S. omalianus— England
G. hannibalensis — Ohio i G. hannibalensis — Nevada
rr 10 20 30 40 ie) 15 2.0 25
A % Length Anterior to Umbo | B Lengtn/ueignt
TT
G. cuyahoga— Ohio S. omalianus— England eke eS el
S. variabilis — England ae 6 pleno— lowa =
6. plena—lowa qe SS G. hannibalensis —lowa ==
G. rostrata — Ohio aE G. hannibalensis — Ohio | |
Marshall ss.— Mich =o Marshall ss.— Mich See)
G hannibalensis — Mo., (Branson) t S. variabilis— England face ok a ee ee
G. hannibalensis—lowa wane Coldwater fm.—Mich Se)
S. omalianus — England eee | G. hannibalensis — Nevada |
Coldwater fm.— Mich len RS Ans Ore <) G. hannibalensis — Mo.,(Branson) | |
G honnibalensis — Nevada tf
65° 70° ache 80° 15 2.0 2.5 3.0
és Hinge—Sulcus Angle D Height/\ 79 Thickness
Text-figure 4+—Range of variation in characters of Grammysia
omaliana omaliana and Grammysia omaliana hydei. All “species’”
listed on the figure are included by the writer in one or another of
these subspecies. The figure illustrates overlapping nature of these
characters in some previously described “species” and in specimens
from different geographic localities. Measurements were compiled
from 7 specimens of Grammysia plena from the Yellow sandstone,
Kinderhook group, at Burlington, Iowa (2 syntypes, AMNH, No.
6570/1 and 5 topotypes, UMMP, No. 1486, identified by Alexander
Winchell) ; 4 specimens of Grammysia hannibalensis from the Kin-
derhook group at Burlington, Iowa, (USNM, Nos. 47334 and 67784) ;
8 specimens of Sanguinolites omalianus from the Lower Carboniferous,
Visean zone D, Thorpe Cloud, Derbyshire, England, (Wheelton Hind
collection, BMNH, Nos. L.46454, 1.46460, L.46461, L.46463, P.L. 3583-
P.L. 3586); the figures of Grammysia hannibalensis from the
Louisiana limestone at Louisiana, Mo., shown by Williams (1941,
pl. 9, figs. 41-44) ; 8 specimens from Michigan glacial drift but, as in-
dicated by lithology, originating in the Coldwater formation (UMMP,
Nos. 37322-37329); 2 specimens from the Marshall sandstone at
Alan’s quarry and Fayette quarry, Hillsdale Co.. Michigan
(UMMP, Nos. 35715 and 37611 respectively) ; 1 specimen of Gram-
mysta hannibalensis from the Lower Carboniferous on the east slope
of a small hill on the east side of Secret-cafon road, Eureka District,
omaliana hydei but many characters of this subspecies form
a continuous series with those of G. omaliana omaliana.
Allorisma hannibalensis was first described by Shumard
(1855, p. 206, pl. C, fig. 19). Neither a lunule nor an es-
cutcheon is noted in Shumard’s desc ription and his figure
is not sufficiently good to prove the presence or absence of
Nevada (hypotype, USNM, No. 14384); the figures of Grammysia
cuyahoga from the Sharpsville sandstone, at Brandywine Creek, Little
York, Summit Co., Ohio, shown by Hyde (1953, pl. 38, figs. 3-7)
{Hyde’s specimens are lost, as are those of Herrick, the author of the
species]; 8 specimens of Sanguinolites variabilis from the Carboni-
ferous limestone, Lowick, Northumberland, England, (Sedgwick
Mus. Nat. History, syntypes, Nos. E 1068, E 1069, hypotypes and
topotypes, Nos. E 1070-E 1075); the figures of Grammysia rostrata
from the upper part of the Black Hand member, Cuyahoga forma-
tion, Thomas Doyle farm, near Byer, Vinton Co., Ohio, shown by
Hyde (1953, pl. 38, figs. 14-19) [Hyde's specimens are lost]; the
figures of Grammysia hannibalensis from the Northview siltstone,
Northview, Mo., shown by Branson (1938, p. 34, pl. 23, figs. 4-6); and
the figures of Grammysia ? hannibalensis from the Waverly sandstone
at Medina, Ohio, shown by Meek (1875, pp. 300-301, pl. 16, figs. 5a, b,
ic) is
A.—Variation in per cent
umbo; B.—Variation in the
of total shell length which is anterior to
length/height ratio; C.—Variation in the
posterior angle between the hinge line and the sulcus; D.—Variation
in the height/1/2 thickness ratio. Distortion of valves due to com-
pression may have influenced the measurements upon which this fig-
ure is based.
these structures. Examination of Shumard’s description and
figure has convinced the writer that Allorisma hannibalen-
sis Shumard is conspecific with the specimens figured as
Grammysia hannibalensis by Hyde (1953, p. 305, pl. 38,
figs. 1, 2). These latter specimens, collected from the Byer
member of the Logan formation at Sciotoville, Ohio, are
MIssIssIPPIAN DIMYARIAN
L~~ /3>—~ Ss AS
Text-figure 5—Posterior and umbonal outlines of Grammysia
omaliana omaliana and Grammysia omaliana hydei arranged so as
to show variation and gradational character. All figures of specimens
have been reduced to uniform size for ease of comparison. In some
cases growth lines rather than outlines were used because the edges
of the valves were broken.
Identification of specimens:
1) “Sanguinolites omalianus,” Visean D zone, Derbyshire, Eng-
land, (BMNH, No. L. 46463); 2) “Sanguinolites variabilis,’ Carboni-
ferous limestone, Northumberland, England, (hypotype and topotype
Sedgwick Mus. Nat. History, No. E. 1073); 3) “Grammysia rostrata,”
Cuyahoga fm., Ohio, (lost syntype, Hyde, 1953, pl. 38, fig. 14);
+) “Grammysia hannibalensis,’ Waverly ss., Ohio. (hypotype, Meek,
1875, pl. 16, fig. 5a); 5) “Grammysia cuyahoga,”’ Sharpsville ss., Ohio,
(lost hypotype, Hyde, 1953, pl. 38, fig. 6) “Sanguinolites omalianus,”
Visean D zone, Derbyshire, England, (BMNH, No. L. 46454) ; 7) Gram-
mysia omaliana hydei, Coldwater fm., Michigan, (UMMP, No.
37325); 8) “Sanguinolites omalianus,” Visean D zone, Derbyshire,
England, (BMNH, No. L. 46460); 9) Grammysia omaliana hydei,
Coldwater fm., Michigan, (UMMP, No. 37326); 10) “Grammysia
cuyahoga,’ Sharpsville ss., Ohio (lost hypotype, Hyde, 1953, pl. 38,
fig. 3); 11) “Grammysia plena,” Kinderhook, Iowa, (UMMP, No.
1486) ; 12) “Sanguinolites variabilis,’ Carboniferous limestone, North-
umberland, England (Sedgwick Mus. Nat. Hist., hypotype and topo-
PELEGYPODS: DRISCOLI 95
housed in the Ohio State University collections [Cat. No.
13787 (12642) ] and have been examined by the writer. The
specimen illustrated by Hyde (1953, pl. 38, fig. 1) shows a
distinct lunule.
Hyde (1953) pointed out in reference to his “species”
that (p. 305) it agrees very well with Shumard’s
original figure and especially so with Hall’s specimen fig-
ured from Hannibal, Missouri (Natural History of N.Y.;
Pal., Vol. V, pt. 1, pl. LXI, fig. 33).” The two specimens
figured by Hall (1885, pl. 61, figs. 29, 30) (AMNH, No.
6568/2) have been examined by the writer and are prob-
ably conspecific with Allorisma hannibalensis Shumard
(1855) and Grammysia hannibalensis Hyde (1953
It is beyond the scope of this paper to examine closely
the taxonomic position of the specimens figured by Shu-
mard (1855, pl. C, fig. 19), Hall (1885, pl. 61, figs. 29, 30,
33), and Hyde (1953 pl. 38, figs. 1, 2). Preliminary ex-
amination indicates that these valves are more regularly
ovate than Grammysia omaliana omaliana and Grammysia
omaliana hydei and that their concentric ribs are stronger,
broader, and bifurcate only rarely.
Grammysia hannibalensis was reported by Walcott (1884,
p- 244) from the “Carboniferous Group, lower portion, on
east slope of a small conical hill on east side of Secret-cafion-
road Canon, Eureka District, Nevada.” Certainly the fig-
ured specimen (pl. 20, fig. 4) does not belong to the present
type, E. 1074); 13) “Sanguinolites variabilis,’ Carboniferous lime-
stone, Northumberland England, (Sedgwick Mus. Nat. Hist., hypo-
type and topotype, E. 1071) ; 14) “Grammysia hannibalensis,” Louisiana
Is.. Missouri (hypotype, Williams, 1941, pl. 9, fig. 41); 15) “Gram-
mysia rostrata,’ Cuyahoga fm., Ohio (lost syntype, Hyde, 1953, pl.
38, fig. 15); 16) ‘“Sanguinolites omalianus,’ Visean D zone, Derby-
shire, England, (BMNH, No. L. 46461); 17) “Grammysia cuyahoga,”
Sharpsville ss., Ohio, (lost hypotype, Hyde, 1953, pl. 38, fig. 7);
18) “Grammysia cuyahoga,” Sharpsville ss., Ohio, (lost hypotype,
Hyde, 1953, pl. 38, fig. 5); 19) Grammysia omaliana hydei Cold-
water fm., Michigan, (UMMP, No. 37329); 20) “Grammysia hanni-
balensis,” Kinderhook, Iowa, (USNM, No. 47334); 21) “Grammysia
plena,” Kinderhook, Iowa, (UMMP, No. 1486); 22) “Grammysia
hannibalensis,’ lower Carboniferous, Nevada, (USNM, hypotype, No.
14384); 23) “Grammysia plena,’ Kinderhook, Iowa, (UMMP, No.
1486); 24) “Grammysia hannibalensis,’ Kinderhook, Iowa, (USNM,
No. Cu. 19608, 67784); 25) ‘“Sanguinolites omalianus,’ Visean D
zone, Derbyshire, England, (BMNH, P.L. 3586); 26) “Sanguinolites
omalianus,’ Visean D zone, Derbyshire, England, (BMNH, P.L. 3585) ;
27) Grammysia omaliana hydei, Coldwater fm., Michigan, (UMMP,
No. 37322); 28) “Grammysia rostrata,’ Cuyahoga fm., Ohio, (lost
syntype, Hyde, 1953, pl. 38, fig. 16) ; 29) “Grammysia rostrata,” Cuya-
hoga fm., Ohio, (lost syntype, Hyde, 1953, pl. 38, fig. 19) ; 30) “Gram-
mysia hannibalensis,’ Waverly ss., Ohio, (hypotype, Meek, 1875, pl. 16,
fig. 5b); 31) “Sanguinolites variabilis,’ Carboniferous limestone,
Northumberland, England, (Sedgwick Mus. Nat. Hist., syntype, 1069) ;
32) “Grammysia hannibalensis,”’ Northview siltstone, Missouri, (lost
hypotype, Branson, 1938, pl. 23, fig. 5); 33) Grammysia omaliana
omaliana, Marshall ss., Michigan, (UMMP, No. 37611); 34) “San-
guinolites omalianus,’ Visean D zone, Derbyshire, England, (BMNH,
P.L. 3584): 35) Grammysia omaliana omaliana, Marshall ss.,
Michigan, (UMMP, No. 35715); 36) Grammysia omaliana hydet,
Coldwater fm., Michigan, (UMMP, No. 37327); 37) “Grammysia
rostrata,’ Cuyahoga fm., Ohio, (lost syntype, Hyde, 1953, pl. 38, fig.
18).
96 PALAEONTOGRAPHICA AMERICANA (V, 35)
rABLE 2.—COMPARISON OF MEAN HEIGHT, MEAN LENGTH, AND NUMBER OF RIBS PER 0.5 CM (COUNTED NEAR MID-
HEIGHT ON ANTERIOR PART OF VALVE) OF GRAMMYSIA OMALIANA SHOWING VARIATION IN PREVIOUSLY DIF-
FERENTIATED SPECIES AND IN SPECIMENS FROM DIFFERENT LOCALITIES. The number of measurements, from either
specimens or figures, which were used in each calculation is shown in parentheses. Allorisma hannibalensis Shumard is not included in
G. omaliana.
Species Horizon
Grammysia omaliana omaliana Marshall ss.
"Sanguinolites omalianus" Visean D zone
"Grammysia hannibalensis" Kinderhook
CGrammysia omaliana hydei Coldwater fm.
"Sanguinolites variabilis
"Grammysia hannibalensis"
'"Grammysia plena" Kinderhook
"Grammysia hannibalensis" Waverly ss.
"Grammysia rostrata" Cuyahoga fm.
"Grammysia cuyahoga"
Allorisma hannibalensis
"Grammysia hannibealensis"
species. The writer has examined Walcott’s type material,
which consists of ten specimens, USNM. No. 14384. One of
these specimens is clearly not a member of the present
genus. Eight of the specimens are represented by Walcott’s
figure 4 on plate 20 and are not conspecific with the pres-
ent species. ‘The tenth specimen, although not well pre-
served, is thought to be Grammysia omaliana omaliana
and is illustrated on Plate 14, figures 42-44, of the present
paper.
Claypole (1886, pp. 242-243, 248) reported Grammysia
hannibalensis Measures” near
from the “Lower Coal
Wilkes-Barre, Pennsylvania. Claypole’s specimens are un-
figured and have not been located by the writer. The de-
scription given by Claypole is insufficient to allow any con-
clusion concerning the taxonomic position of the specimens.
Many of the type specimens of “species” included in the
above synonymy have been lost (e.g., those of Grammysia
hannibalensis Herrick, 1888, vol. 3, p. 75; Allorisma cuya-
hoga Herrick, 1888, vol. 4, p. 28-29, pl. 10, fig. 34; 1893, pl.
22, fig. 17; Grammysia cuyahoga Hyde, 1953, pl. 38, figs.
3-7; Grammysia rostrata Hyde, 1953, pl. 38, figs. 14-19). In
these cases it has been necessary to rely solely upon ayail-
able figures and descriptions. In all cases it appears to the
Carb. limestone
Louisiana limestone
Sharpsville ss.
Louisiana limestone
Northview siltstone
Locality Number of
ribs per
OSD em
Michigan
Derbyshire
lowa
Michigan
Northumberland
Missouri
Iowa
Ohio
Ohio
Ohio
Missouri
Missouri
writer that the “species” included in the synonymy possess
characters sufficiently diagnostic to allow their inclusion in
Grammysia omaliana omaliana. Characteristics of most
value are general shape, arrangement, and strength of con-
centric ridges, concentric striae, the commonly compressed
and undulating postumbonal slope, the moderately pro-
nounced umbonal ridge, and the sulcus from beak to
ventral margin.
Grammysia omaliana omaliana is distinguished from
Wilkingia winchelli (Meek) (1871, pp. 167-168, and 1875,
pp. 311-312, pl. 16, figs. 3a, b, c) by the generally more
elongate form of the latter, the length of which ranges from
about 2 to 314 times its height. The characteristic bifur-
cating pattern of the concentric ridges on Grammysia omali-
ana omaliana is lacking on Wilkingia winchelli, in which
the concentric ridges extend unaffected across the sulcus,
and the extreme prosogyrate character of Wilkingia win-
chelli is distinctive.
Leptodomus constrictus McCoy (1855, p. 396, pl. 2A, fig.
10*) shows considerable similarity with the present species
and, almost certainly, they are congeneric. Whidborne
(1896, pp. 75-76, pl. 8, figs. 8, 9) discussed this species as
Leptodomus constricta stating (p. 76), “Grammysia Hanni-
MIssISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLI 97
balensis, Shumard agrees more nearly with our shell in di-
mensions, but its umbo is more anterior and oblique, and
its constriction seems to range more backward.”
The writer has examined a cast of the specimen shown by
Whidborne in his plate 14, fig. 9 (Univ. of Cambridge, No.
H. 353), and photographs of McCoy’s holotype (Univ. of
Cambridge No. H. 714), and of the specimen mentioned by
Whidborne (p. 75) from ‘Top Orchard Quarry (Univ. of
Cambridge, No. H. 547) . It is not clear whether Whidborne
was differentiating Leptodomus constrictus from Shumard’s
type of Grammysia hannibalensis or from other specimens
which have been referred to that species but which are here
called Grammysia omaliana omaliana. If the latter is the
case, the writer cannot agree that the outline, the position
of the umbo, or the direction of the sulcus can be used for
differentiation of the two species. Text-figure 5 indicates
variation in the outline of the umbonal region of Gram-
mysia omaliana omaliana and Grammysia omaliana hydei.
The outline of the umbo of Leptodomus constrictus is not
so distinctive that it can be separated from those of a num-
ber of the forms illustrated. Measurements made on two
photographs of Leptodomus constrictus, one of which is of
the holotype, indicate that 309%, to 34°% of the total length
is found anterior to the umbo. This is a high percentage
when compared to that of the present species, but it does
not fall outside the range of Grammysia omaliana omaliana.
It should also be noted that the specimen figured by Whid-
borne (1896, pl. 14, fig. 8) has only about 28° % of its total
length anterior to the umbo.
The posterior angle between the hinge line and the sul-
cus of McCoy’s holotype of Leptodomus constrictus is ap-
proximately 73° which, as shown in ‘Text-figure 4, C, is not
distinctive from the same angle in the present species.
The general form, sulcus, concentric ridges, and_post-
umbonal slope all indicate that McCoy’s species is closely
related to Grammysia omaliana omaliana. The former may
be distinguished by its relatively shorter length. Two photo-
graphs of Leptodomus constrictus on which measurements
could be made, one of which is a photograph of the holo-
type, indicate a length/height ratio of 1.3. It is true that
the specimen figured by Whidborne (1896, pl. 8, fig. 8) has
a length/height ratio which overlaps into that of the pres-
ent species but, in general, it appears that Leptodomus
constrictus is relatively shorter. Also, it appears that little
if any bifurcation of the concentric ridges takes place on
L. constrictus. In the cast and photographs which were ex-
amined, the concentric ridges on L. constrictus are not pres-
ent on the posterior part of the valve. In Grammysia
omaliana omaliana they weaken or are reduced to striae on
this part of the valve but they are not completely absent.
A few species other than the present one possess a similar
pattern of bifurcating concentric ridges. Grammysia sub-
arcuata Hall (1885, p. 375, pl. 61, figs. 10-22; pl. 93, fig.
26) is one of these. From Hall’s figures it seems probable
that he has figured more than one species under the name
Grammysia subarcuata. Whether this is true or not, most of
Hall's figures illustrate specimens which can be distin-
guished from the present species on the basis of the former’s
strongly sigmoidal ventral borders and their more pro-
nounced prosogyrate character.
In conclusion, the writer would emphasize that within
the group of shells here included in Grammysia omaliana
omaliana there is a great deal of variation. It is possible to
find valves within the series which appear to be specifically
distinct, but it is the writer’s opinion that the species con-
sists of a species of gradational forms. Possibly a number of
zoologic species are here grouped under Grammysia omal-
tana omaliana. If this is true, it is regrettable that variation
within the hard parts preserved for paleontologic study does
not permit differentiation into paleontologic species. Fur-
ther examination of this group of pelecypods may reveal
that differentiation is possible but, at the present time, it
seems inadvisable.
Types and occurrence.—The following 30 specimens have
been examined and must be considered hypotypes of Gram-
mysia omaliana omaliana: four specimens labeled “Gram-
mysia hannibalensis” from the Kinderhook group at Bur-
lington, lowa, USNM. Nos. 47334 and 67784 (not discussed
in earlier literature) ; “Sanguinolites variabilis,” eight speci-
mens, Carboniferous Limestone at Lowick, Northumber-
land, England, Sedgwick Mus. Nat. Hist., Nos. E. 1068, E.
1069, E. 1070-E. 1075 (Nos. E. 1068 and E. 1069 are syn-
types, McCoy, 1855, p. 508); “Sanguinolites omalianus,”
eight specimens. Lower Carboniferous, Visean D zone, at
Thorpe Cloud, Derbyshire, England, BMNH, Wheelton
Hind Collection, Nos. L. 46454, L. 46460, L. 46461, L.
46465, P.L. 3583-P.L. 3586 (not discussed in earlier litera-
ture); “Grammysia hannibalensis,’ one specimen, Lower
Carboniferous on east slope of small hill on east side of
Secret-canon-road, Eureka District, Nevada, USNM, No.
14584, Loc. No. 655 (discussed but not figured by Walcott,
1884, p. 244); “Grammysia plena,” two specimens, Yellow
sandstone, Kinderhook
AMNH, No. 6570/1 (syntypes
by Hall, 1885, pp. 382-383, pl. 61, figs. 51, 32); five speci-
mens labeled “Grammysia plena”’ from the Yellow sand-
group, at Burlington, Iowa,
described and _ figured
stone, Kinderhook group, at Burlington, lowa, UMMP, No.
1486 (not discussed in earlier literature) ; “Sanguinolites
98 PALAEONTOGRAPHICA AMERICANA (V, 35)
Marshall
Alan’s and Fayette quarry, Hillsdale County, Michigan,
UMMP, Nos. 35715 and 37611 respectively. No. 35715
was one of Winchell’s syntypes, 1865, p. 128; No. 37611 is
hannibalensis,” two specimens, sandstone, at
not discussed in earlier literature.
Grammysia omaliana hydei, subsp. nov.
Plate 14, figures 10-12, 16-18, 25-26, 40-41
Grammysia2 hannibalensis Meek, 1875, pp. 300-301, pl. 16, figs. 5a,
Sa ae rostrata Hyde, 1953, pl. 38, figs. 14-19, mom. nud.
Grammysia cf. plena Hyde, 1953, p. 306, pl. 38, figs. 12, 13; pl. 39,
fig. 10.
Description.—The description given above for Grammysia
omaliana omaliana also applies to Grammysia omaliana
hydei with the following exceptions. The umbonal region
of G. omaliana hydei rises higher above the hinge line and
commonly is more pointed in outline, as contrasted to the
more rounded and lower umbonal outline of G. omaliana
omaliana. The posterior end of G. omaliana hydei also dif-
fers in commonly being more pointed at the extremity and
with this point placed below the mid-height of the valve.
Remarks.—Mayyr, et al., (1953, p. 30) said, “Not more
than one subspecies of any one polytypic species can exist
in breeding conditions in any one area.” Satisfaction of this
rule is often difficult in paleontologic speciation. Despite
this difficulty the writer designates the present subspecies
because of the distinct morphologic characters which are
present in a large majority of the specimens collected from
glacial drift in Michigan but thought to have originated in
the Coldwater formation and those which have been re-
ported and figured by Meek (1875, pp. 300-301, pl. 16,
figs. 5a, b, c) and Hyde (1953, p. 306, pl. 38, figs. 12-19;
pl. 39, fig. 10) from Ohio.
Mayr, et al., (1953, p. 31) continued the discussion of
subspecies to say “To qualify as a subspecies, such an as-
from other
. The difference must be sufficiently great so
semblage must be taxonomically different
species.
that it is possible to identify the great majority of specimens
without knowledge of their provenience. For that purpose,
.” Al-
though not enough specimens of the present subspecies are
many taxonomists adhere to the 75 per cent rule.
available for statistical analysis, certain observations indi-
cate that distinct morphologic differences separate most
specimens of G. omaliana hydei from those of G. omaliana
omaliana.
The posterior extremities shown in Text-figure 5 were
arranged as nearly as possible in a gradational series. It is
noteworthy that four of the ten specimens here called G.
omaliana hydei are found at the end of this series, where
the most sharply pointed extremities are grouped.
A considerably more striking arrangement is found in the
series of umbonal outlines present on the same figure.
These outlines, arranged so as to put more prominent and
sharper umbos at the end of the series, show a gradation
in which no distinct breaks are apparent. However, of the
last ten umbonal outlines in the series (Fig. 5, Nos. 36, 37,
6, 30, 4, 7, 28, 15, 19, 3) only one (No. 6) does not belong
to a member of the present subspecies. No member of G.
omaliana hydei is found in the low umbo part of the series.
For these reasons it is felt that a great majority of the
specimens belonging to G. omaliana hydei can be recog-
nized by their higher and more sharply pointed umbos and,
less commonly, by their more pointed posterior extremities.
Types and occurrence.—The holotype of Grammysia
omaliana hydei, UMMP, No. 37328, and seven paratypes,
UMMP, Nos. 37322-37327, 37329, were all collected from
glacial drift in Michigan. Their lithology indicates that they
all probably originated in the Coldwater formation. Gram-
mysia omaliana hydei also has been reported from the
upper part of the Black Hand member, Cuyahoga forma-
tion, near Byer, Vinton County, Ohio, by Hyde (1953, pl.
38, figs. 14-19) and from the Waverly sandstone at Medina,
Ohio, by Meek (1875, pp. 300-301, pl. 16, figs. 5a, b, c).
ORDER FILIBRANCHIA
FAMILY PARALLELODONTIDAE
Genus PARALLELODON Meek and Worthen, 1866
Parallelodon Meek and Worthen, 1866, p. 17 (=Macrodon Lycett, in
Strickland and Buckman, 1845, p. 98, non Macrodon Miiller, 1842,
p. 308, nec Macrodon Schinz, 1822, p. 482); Arkell, 1930, pp. 297-
306, in part; Kobayashi and Ichikawa, 1950, p. 238.
Type species.—Macrodon rugosus Buckman.
Remarks.—TVhe rather complicated nomenclatorial prob-
lems associated with this genus have been reviewed by the
writer elsewhere (1961, pp. 1090-1093) .
Subgenus Cosmetodon Branson, 1942
Cosmetodon Branson, 1942, pp. 247-249 (=Beushausenia Arkell, 1930,
pp. 297-306, non Beushausenia Maillieux, 1913, p. 33, mec Beushau-
senia Cossmann, 1897, p. 93).
Type species.—By original designation of Branson, 1912,
p. 247, Beushausenia keyserlingi (d’Orbigny) .
Remarks.—Branson (1942, p. 248) has pointed out that:
Shells of Cosmetodon differ from those of the subgenus
Parallelodon in that the anterior and posterior corners of
the hinge are never alate and the greatest length is below
the midheight rather than along the hinge.
Parallelodon (Cosmetodon) sp. aff. P. ovatus (Hall)
Plate 15, figures 30-39
Description.—Shell elongate, suboval, moderately gibbous,
higher posteriorly, length more than twice anterior height
MISSISSIPPIAN DIMYARIAN PELEGYPODS! DRISCOLT 99
and slightly less than twice the posterior height. Dorsal
margin very gently curved. Ventral margin subrectilinear,
slightly sigmoidal due to broad shallow sinus extending
from umbonal region to ventral margin near mid-length of
valve. Posterior margin evenly and gently rounded into
dorsal and ventral borders, posterior extremity being
slightly below mid-height of valves. Anterior margin
rounded.
Prosogyrate, beaks depressed, rising only slightly above
hinge line near anterior extremity of valves. Umbonal ridge
absent, or weakly developed near beaks. Greatest gibbosity
is posterior to beaks, near center of valves.
Deep, suboval, anterior adductor muscle scar found in
anterior extremity of valve immediately anterior to broad,
shallow sinus. Posterior side of anterior adductor scar is
more deeply impressed than anterior side. Posterior ad-
ductor scar not preserved.
Dentition only partially preserved on specimens ex-
amined. Posteriorly, two long lateral teeth and two sockets
lie subparallel to dorsal margin in each valve (PI. 15, fig.
37). The more ventral of the two teeth extends further
toward the posterior extremity than does the more dorsal
tooth. Immediately anterior to beaks two small nodelike
teeth are present in left valve (PI. 15, fig. 39). Anterior
dentition of right valve unknown.
Surface ornamentation poorly preserved on writer's speci-
mens; consists of fine, subequally spaced, concentric striae.
Remarks.—The present species is closely related to four
other species which have been previously described; Paral-
lelodon hamiltoniae (Hall), P. ovatus (Hall), P. sulcatus
Weller, and P. irvinensis (Foreste). Evaluation of the
validity of these species must await a more detailed exam-
ination. Size and general shape are characters which appear
to be of little value for recognition of different forms. Hyde
(1953, p. 301) tabulated height/length ratios for P. irvinen-
sis (0.73-0.56) , P. sulcatus (0.58-0.50), and P. hamiltoniac
(0.64-0.45) . Hall’s figures of P. ovatus (1885, pl. 51, fig. 8;
pl. 93, fig. 16) both show height/length ratios of 0.55. The
ratios of the writer’s three specimens from the Marshall
sandstone range from 0.40 to 0.62. Overlap between these
ratios does not allow differentiation.
Hall (1885, p. 351) says of P. ovatus, “Anterior hinge
teeth minute, oblique; posterior teeth elongate, very slight-
ly curved, one long and one short in each valve.” This de-
scription could well be applied to Marshall sandstone speci-
mens, except for the fact that anterior dentition in Marshall
specimens consists of two minute nodelike teeth in the
left valve rather than oblique teeth.
It is also noteworthy that there is some discrepancy be-
tween the two figures of P. ovatus illustrated by Hall
(1885). On his plate 51, figure 8, a left valve is shown pos-
sessing two posterior lateral teeth. On his plate 93, figure
16, a left valve is shown with three posterior lateral teeth.
Both specimens are from the Waverly group of Ohio.
Specimens of Parallelodon (Cosmetodon) sp. aff. P. ova-
tus from the Marshall sandstone have, as noted above, only
two posterior lateral teeth. Several left valves of Parallelo-
don sp. (Pl. 15, figs. 40-48) from glacial drift, but believed
to have originated in the Coldwater formation, have been
examined. These are similar to Parallelodon (Cosmetodon)
sp. aff. P. ovatus except that they do, in fact, have three
oblique anterior teeth as well as three posterior lateral
teeth. Further study will, in all probability, prove that
these Coldwater forms are assignable to one of the species
discussed above.
Specimens and occurrence.—The writer has figured three
specimens of Parallelodon (Cosmetodon) sp. aff. P. ovatus,
UMMP, Nos. 37401-37403. All three are from the Marshall
sandstone, the first two being collected at Battle Creek,
Calhoun County, Michigan, and No. 37403 at Marshall,
Calhoun County, Michigan.
In summary, Parallelodon (Cosmetodon) Jo, chat, I?
ovatus 1s known to occur only in the Marshall sandstone
of Calhoun County, Michigan. Closely related forms, P.
ovatus and P. irvinensis, which may prove to be synony-
mous, occur in the Waverly group of Ohio.
Parallelodon (Cosmetodon) marshallensis (Winchell)
Plate 16, figures 1-5
Sanguinolites marshallensis Winchell, 1862, p. 415; ?1871, py 256:
Non Sanguinolites marshallensis 2 Herrick, 1888, vol. 3. p. 67, pl. 5,
fig. 11; pl. 7, fig. 10 (= Palaconeilo truncata Hall).
Parallelodon depressus Hyde, 1953, pp. 299-300, in part.
Original description.— (Winchell, 1862, p. 415) .
Shell of medium size, transverse, equivalve, ellipsoidal in outline,
with subterminal beaks. Hinge line apparently edentulous, straight,
flattened and elevated posteriorly, terminating one fourth the length
of the shell from the posterior extremity, at which point is the
greatest height of the shell. Posterior extremity a semi-ellipse; anterior
subtruncate above, regularly rounded below; a sinus in the ventral
border one-third the shell-length from the anterior end, from which a
diminishing furrow extends to the flattish, straight, incurved beak.
Greatest thickness of shell on the middle line a little nearest to the
anterior end. Surface marked by about three remote, deep, concentric
grooves, and numerous fine lines of growth.
Length 1:2 (100); greatest height ‘63 (52); thickness 36 (30);
projection of anterior end beyond beak -09 (7).
Locality —Marshall.
This species seems to be destitute of the elongated posterior
escutcheon characteristic of McCoy’s Sanguinolites, but agrees perfectly
with Professor King’s modified ideas of Al/lorisma, (Perm. Foss. pp.
162 and 196). Some hesitation is shown, however, among paleon-
tologists about adoption of the latter name, which McCoy regards
as a synonym of Sanguinolites.
Revised description.—Shell subelliptical, higher _ pos-
teriorly, length more than twice the anterior height and
100 PALAEONTOGRAPHICA
slightly less than twice the posterior height. Beaks sub-
terminal, rising only slightly above dorsal margin. Dorsal
margin straight, length equal to somewhat more than %
of total length of valve. Anterior margin truncate above,
abruptly rounded below, forming angle of approximately
115° with dorsal margin. Ventral margin sinuous, reflecting
broad sulcus extending from umbo to ventral margin. Pos-
terior border evenly and broadly rounded dorsally and
ventrally, more abruptly curved terminally. Posterior ter-
mination of valve approximately at mid-height.
Moderately convex, greatest thickness near mid-length
of valves, tapering evenly to posterior extremity but main-
taining considerable gibbosity to near anterior extremity.
Strong, broad sulcus extends posteroventrally from umbo to
ventral margin, reflected in constriction of growth lines and
of ventral margin.
Umbonal ridge not pronounced. Postumbonal slope flat-
tened, becoming concave toward dorsal margin, which is
subalate posteriorly.
Surface ornamentation of a few, commonly three or
more, distinct, evenly and widely spaced, concentric lamel-
lae and of finer striae of growth.
Interior unknown. Dentition unknown.
Remarks.—Because Winchell published no illustrations
of the specimens which he originally assigned to Sanguino-
lites marshallensis, considerable confusion concerning the
characteristics of this species has arisen. Hyde (1953, p.
297) discussed this problem (see also the partial discussion
included under Palaconcilo truncata of the present paper) .
The writer has examined and illustrated (PI. 16, figs.
1-3) the holotype of Parallelodon (Cosmetodon) marshal-
lensis (Winchell). This specimen, from the Marshall sand-
stone at Marshall, Calhoun County, Michigan, was figured
by Winchell in unpublished illustrations held by the Uni-
versity of Michigan.
Winchell’s holotype of the present species is clearly dis-
tinct from the forms here assigned to Palaconeilo truncata
Hall, with many of which it has previously been considered
synonymous. It is equally apparent that the holotype is not,
in fact, a species of Palaconezlo.
The general form of the present species agrees very well
with members of the genus Parallelodon. However, certain-
ty regarding this generic assignment must await study of
specimens in which dentition is preserved.
Hyde (1953, pp. 299-300) described, but did not illus-
trate, a new species, Parallelodon depressus. The writer has
examined Hyde’s four primary types of this species (OSU,
No. 19671). Two of these specimens, one of which is the
holotype of P. depressus, are figured here for the first
tuume (Pl. 16, figs. 4-5). These are considered synonymous
AMERICANA (V, 35)
with P. (Cosmetodon) marshallensis (Winchell) . ‘The two
remaining specimens of Hyde’s primary types are not con-
sidered synonymous with the present species and are prob-
ably not members of the genus Parallelodon.
The present species differs from Parallelodon sulcatus
(Weller) in its larger size, more abrupt truncation of the
dorsal part of the anterior margin, and its less conspicuous
umbonal ridge. The dorsal portion of the posterior margin
of P. sulcatus is subtruncate whereas that of the present
species is not, being nearly symmetrical with the ventral
portion. The strong, evenly spaced lamellae of the pres-
ent species are not characteristic of P. sulcatus.
Types and occurrence.—Winchell’s holotype of Parallelo-
don (Cosmetodon) marshallensis, UMMP, No. 26877, is a
right valve from the Marshall sandstone at Marshall, Michi-
gan. From the same locality Winchell collected a poorly
preserved paratype, UMMP, No. 44272 (unfigured) . Hyde’s
Ohio specimens (OSU, No. 19671) must be regarded as
hypotypes.
P. (Cosmetodon) marshallensis (Winchell) occurs in the
Marshall sandstone of Calhoun County, Michigan, and in
the Allensville member, Logan formation, at the Vogel-
meier quarry, Newark, Ohio, and at Rushville, Ohio.
ORDER PRAEHETERODONTA
FAMILY MYOPHORIIDAE
Genus SCHIZODUS King in Murchison, de Verneuil, and
Keyserling, 1845
Schizodus King, 1844, p. 313 (nom. nud.) ; King in Murchison, ef al.,
1845, pp. 308-309; 1850, pp. 185-188; Hind, 1898, pp. 212-217; Cox,
1951, pp. 362-371 (see Hind, 1898, for other references).
Type species —By original designation of King, im Mur-
chison, et al., (1845, p. 308) Schizodus obscurus (J. Sow-
erby) .
Remarks.—In_ 1845 King (in Murchison, De Verneuil,
and Keyserling, p. 509) defined Schizodus as having two
teeth in each valve. In 1850 (p. 185) King stated that the
right valve has two cardinal teeth and that the left valve
has three, and noted that the previous error was due to
overlooking the small posterior tooth in the left valve. Hall
(1885, p. 39), Grabau and Shimer (1909, p. 482), Shimer
and Shrock (1949, p. 101) and others have contended that
Schizodus has only two teeth in the right valve, but Hind
(1898, p. 214) described a third tooth, weakly developed
and situated anterior to the other two, in the right valve.
Hind’s figure of Schizodus pentlandicus (pl. 16, fig. 4) does
appear to show such a tooth. None of the species here
assigned to Schizodus have been observed to have more
than two teeth in the right valve.
King (7m Murchison, De Verneuil and Keyserling, 1845,
MIUSSISSIPPIAN DIMYARIAN PELECYPODS: Driscoll LO]
p- 308) stated that “Les dents de la valve gauche sont
placées en avant de celles de la valve droit. - He reat-
firmed this relationship between the valves in 1850 (p.
185). Hind (1898, p. 214) said that “. in direct opposi-
tion to King’s statement, the teeth of the right valve are
always in front of those in the left.” Valves of the species
described below possess somewhat stronger dentition than
the type species (see Cox, 1951, pp. 363-364) and articulate
so that a tooth of the left valve is always most anterior.
Nevertheless, the largest cardinal of the right valve is al-
ways anterior to the largest cardinal of the left valve.
Schizodus rostratus (Winchell)
Plate 16, figures 6-21
Sanguinolaria rostrata Winchell, 1865, pp. 129-130.
Original description.— (Winchell, 1865, pp. 129-130) .
Shell rather large, transverse, cuneate-oval in outline, of medium
convexity. Beaks two-fifths the shell length, from the anterior end,
quite prominent, and rather strongly incurved. Greatest convexity
above the middle, continuing along the postero-dorsal slope. Hinge line
somewhat more than one-third the length of the shell, slightly angu-
lated between the beaks; buccal slope slightly curved, the anal nearly
straight; extremities obtusely rounded; ventral margin nearly straight
in the middle region, curved rapidly beyond. Longest dimension equi-
distant between the beaks and venter. Pallial impression deep, without
sinus (?); anterior muscular pit deep on the rostral side, roundish-
oval, striate radially and concentrically; equidistant between the
beaks and the extremity; posterior muscular pit much elongated; a
feeble ridge extends from the beak along the inner border of each
muscular pit—more perceptible posterior. In the right valve a strong
triangular cardinal tooth stands just anterior to the point of the
beak, and is bounded posteriorly by a deep triangular pit, and an-
teriorly by a shallower and narrower one. Nothing further is clearly
known in reference to the hinge. The shell seems to be thick and
externally smooth.
Length, 1°72 (100); height, 1°13 (66); convexity of one valve, “34
(20); distance from beak to anterior extremity, °55 (32); to posterior
extremity 1°21 (70).
Collected at Battle Creek, Michigan, by A. W.
Resembles S. similis Win., but differs in more prominent beaks,
greater convexity and straight ventral margin.
Revised description.—Cuneate-suboval, moderately gib-
bous, beaks approximately two-fifths total length from
anterior extremity. Ventral margin straight in central part.
Anterior margin broadly and evenly rounded. Posterior
margin subtruncate. Dorsal border straight posterior, and
for a short distance anterior, to the beaks, forming an angle
of approximately 140° beneath the incurved beaks.
Beaks prominent, rising well above hinge line, ortho-
gyrate or opisthogyrate, the latter condition being best
shown in maturity or old age.
Pallial line strongly impressed, entire, subtruncate pos-
teriorly (?). Adductor scars strongly marked, particularly
along the posterior side of the anterior adductor and the
anterior side of the posterior adductor. Both adductor scars
prominently marked by radial and concentric sculpture
(PI. 16, figs. 10, 15, 20). A shallow groove extends radially
across the subcircular anterior adductor and joins pallial
line ventrally (Pl. 16, figs. 10, 15). Posterior adductor sub-
oval. Anteriorly and posteriorly, immediately adjacent to
hinge line and above the adductor scars, a small oval ac-
cessory scar is present (PI. 16, figs. 10, 15, 16, 20).
Surface of casts marked by ridges. Anteriorly a single
inconspicuous ridge extends from umbo to anterior ad-
ductor scar. Posteriorly two, and in some cases three, such
cast ridges are found curving away from umbo. The weak-
est and most dorsal ridge absent in certain specimens, ex-
tends from umbo to posterior adductor scar. The most
prominent ridge curves from the umbo, passes close to the
anterior border of the posterior adductor scar, and merges
with the general convexity of the valve post-ventrally. The
third ridge, best developed in mature and old age speci-
mens, is the most anterior of the three posterior cast ridges.
It curves strongly from the umbo, being directed dorsally
in the umbonal region but swinging in a post-dorsal direc-
tion before merging with the general convexity in the
central part of the valve.
Dentition strongly developed. Dentition formula (see
Bernard and Munier-Chalmas in Bernard, 1895, pp. 116-
117), of right valve: -3a-3b-: of left valve: 4a-2-4b.
The cardinal tooth of the left valve (2) is strongly
developed, slightly bifid, subtriangular, and extends ven-
trally from below the beak (PI. 16, figs. 14, 19). Anterior
to this tooth hes a large triangular socket for reception of
cardinal (3a) of the right valve. Posterior to the central
cardinal a narrower triangular socket is present for recep-
tion of cardinal (3b) of the right valve. Two narrow, in-
clined, elongate cardinal teeth extend from the central part
of the hinge anteroventrally (4a) and _ posteroventrally
(4b). Of these two inclined teeth the most anterior (4a)
is more prominent (PI. 16, fig. 19) .
Dentition of the right valve dominated by a strongly de-
veloped, curving, subtriangular, cardinal (3a) (Pl. 16, figs.
8, 18). Anterior to this cardinal a prominent, inclined,
elongate-triangular socket for reception of cardinal 4a is
present. A large socket lies posterior to cardinal 3a for re-
ception of cardinal 2. This socket is bounded posteriorly
by another inclined, weakly developed cardinal (4b). The
most prominent tooth of the right valve is articulated in
front of that of the left. Plate 16, figure 21, illustrates that
cardinal 3a les in front of cardinal 2.
Ligament external, contained in a narrow lanceolate
escutcheon (PI. 16, fig. 19). Shell probably thick, exterior
unknown.
Remarks.—Herrick (1888, vol. 4, pl. 6, figs. 1-4, 6, 10,
12, 13) illustrated a number of species of Schizodus from
the Waverly group of Ohio, There appears to be no close
Lov PALAKONVOGRAPHICA AMERICANA (V, 35)
resemblance between any of these forms and Schizodus
rostratus (Winchell) .
S. rostratus resembles, in general outline and appearance,
the Pennsylvanian and Permian species, Schizodus wheeleri
(Swallow) .
rounded anterior borders and ridged casts. Schizodus ros-
Both forms are elongate and possess evenly
tratus may be distinguished by its straighter ventral mar-
gin, by its more posteriorly placed beaks and by its dis-
tinctive musculature.
Types and occurrence.—Two syntypes collected by Win-
chell in 1863 from the Marshall sandstone at Battle Creek,
Calhoun County, Michigan, and described in 1865 (pp.
129-130) have been examined. UMMP, No. 26884 is here
designated lectotype and No. 44281 paralectotype. Three
other specimens (UMMP, Nos. 35554, 44282, 44283) from
the Marshall sandstone at Holland, Ottawa County, Michi-
gan, are here regarded as hypotypes.
Schizodus rostratus (Winchell) is known to occur in the
Marshall sandstone of southern Michigan.
Schizodus? similis (Winchell)
Plate 17, figures 1-13
Sanguinolaria similis Winchell, 1862, p. 421; 1865, p. 130.
Original description.— (Winchell, 1862, p. 421).
Shell rather large, transversely elliptic, rather appressed. Beaks
a little anterior to the middle of the shell, flat, obtuse, and a little
elevated. Hinge-line about one-third the length of the shell, slightly
angulated under beaks; buccal and anal slopes somewhat straight;
anterior and posterior margins abruptly rounded; ventral margin
regularly curved, except a slight bend in the middle. Longest dimen-
sion equidistant between beaks and venter. Pallial imprssion entire? ;
anterior muscular scar roundish-oval; posterior obliquely pyriform.
A pair of strong internal ridges diverge from beneath the beaks (as
in Tellina), the anterior passing along the posterior side of the
buccal scar, and the posterior along the front margin of the posterior
scar, terminating opposite the lower borders of the respective scars. A
sharp but shallow groove runs along the anterior of the posterior
ridge. Hinge not fully known; a strong triangular cardinal tooth
passes a little obliquely forward across the hinge plate, behind which
is a deep pit, while a shallow one bounds the tooth anteriorly; an
elongate triangular lateral tooth extends in front of the beak, and
apparently another behind the beak. Shell thick; external surface
marked by irregular, fine incremental striae, and a few broad shallow
furrows.
Length 2:0 (100); height 1°11 (55); convexity of one valve ‘23
(11); length of posterior lateral tooth +42 (21); from beak to anterior
extremity 95 (47); to posterior extremity 1°25 (62).
Locality—Marshall, where it is rather abundant.
Revised description.—Shell subelliptical, narrow. Dorsal
margin straight anterior and posterior to beaks, forming
an angle of approximately 140° below beaks. Anterior
margin rather abruptly rounded near mid-height of valve.
Posterior border subtruncate dorsally, abruptly rounded
ventrally. Ventral margin broadly and evenly curved an-
teriorly and posteriorly, somewhat more abruptly rounded
near mid-length of valves.
3eaks distinct, rising only a little above the hinge line,
situated slightly anterior to mid-length of valves. Valves
harrow, tapering evenly anteriorly and_ posteriorly. Ad-
ductor scars prominent. Anterior scar deeper, placed mid-
way between beaks and anterior extremity, adjacent to dor-
sal margin, oval, marked by weak concentric sculpture and
a single thin radial groove which joins pallial line ven-
trally (Pl. 17, fig. 6). In molds a small projection extends
toward beak from the anterior adductor, probably reflect-
ing an accessory muscle scar immediately adjacent to the
anterior adductor (PI. 17, figs. 2, 3, 5, 6). Posterior ad-
ductor subpyriform, situated midway between beak and
posterior extremity adjacent to dorsal margin, marked
by weak concentric sculpture (Pl. 17, figs. 5, 8). Pallial line
entire, truncate below posterior adductor scar.
Three internal ridges present (grooves on molds) . Two
of these are prominent, diverging from the umbonal region
anteriorly and posteriorly. Stronger posterior ridge extends
along anterior border of posterior adductor scar, terminat-
ing at posteroventral extremity of this scar (PI. 17, figs. 5.
8, 12). Anterior ridge extends along posterior border of
anterior adductor scar, terminates at ventral border of
scar (PI. 17, figs. 5, 6). The third internal ridge, weakly
developed, originates on the central portion of umbo and
extends posteroventrally for a short distance before merging
with general convexity of valve (PI. 17, figs. 5, 6). A sharp
narrow groove is present immediately adjacent and anterior
to strong posterior ridge (PI. 17, figs. 5, 7, 8).
Dentition strongly developed, dentition formula (see
Bernard and Munier-Chalmas im Bernard, 1895, pp. 116-
117), of right valve: -3a-3b; of left valve: 4a-2-.
Cardinal tooth of left valve (2) strongly developed, tri-
angular, directed posteroventrally, subbifid, being partially
divided on the ventral surface. Large triangular socket im-
mediately anterior to this cardinal for reception of strongest
cardinal of right valve. Prominent, narrowly triangular
cardinal (4a) lies anterior to this socket and is directed
anteroyentrally. Posterior to cardinal 2 a socket for recep-
tion of cardinal 3b merges into wide flattened area of hinge
(Ray tie il)
In the right valve the subtriangular cardinal (3a) is the
strongest tooth, extends anteroventrally. Below the an-
terior portion of cardinal 3a and the socket which lies
anterior to this tooth, the internal anterior ridge broadens
and merges with the hinge. structure, acting as a support
for cardinal 3a and closing the bottom of the socket which
receives cardinal 4a (PI. 17, figs. 4, 9). This is the only
socket of either valve which is closed ventrally. It is possible
that the corresponding anterior internal ridge of the left
valve supports cardinal da but it does not close the socket
MIUSSISSIPPIAN DIMYARIAN PELEGYPODS: DRiIscoLl 103
for reception of cardinal 3a. Posterior to 3a is a broadly tri-
angular socket for reception of cardinal 2 and a prominent
elongate cardinal (3b) directed posteroventrally.
Shell thin (PI. 17, fig. 12) except in umbonal region and
ridged areas, marked by broad irregular concentric undula-
tions, reflected internally, and regular, closely spaced con-
centric striae (PI. 17, fig. 13
Remarks.—The writer cannot, with certainly, assign the
present species to Schizodus. Typical forms of Schizodus
characteristically possess a more sharply defined umbonal
ridge, a less elongate form, and a greater relative thickness,
than does the present species. The general form of typical
species of Schizodus is distinct.
The present species is tentatively assigned to this genus
largely on the basis of its dentition, which agrees well with
that of other species of the genus. Internal ridges, most
pronounced posteriorly, have been emphasized as a generic
characteristic by Waagen (I88I, p. 232) and are well de-
veloped in the present species. The posteriorly truncated
pallial line also agrees well with that found in more typical
members of the genus.
Types and occurrence.—Winchell’s four syntypes of San-
guinolaria similis (=Schizodus? similis) are held by the
University of Michigan. Of these UMMP, No. 44285 is here
designated lectotype. UMMP, Nos. 44286, 44287, and 26833
(unfigured) are paralectotypes. These specimens are from
the Marshall sandstone at Marshall, Calhoun County,
Michigan. Hypotype, UMMP, No. 44288, is from the Mar-
shall sandstone at Battle Creek, Calhoun County, Michi-
gan. The specimens described by Winchell (1865, p. 130)
from Napoleon Cut, Jackson County, Michigan, have ap-
parently been lost.
Schizodus? similis (Winchell) is known to occur only in
the Marshall sandstone of southern Michigan.
Schizodus sectoralis (Winchell)
Plate 17, figures 14-26
Sanguinolaria sectoralis Winchell, 1862, p. 422.
Original description.— (Winchell, 1862, p. 422).
Shell rather large, subtumid, triangular, with beaks but little in
advance of the middle. Anterior and posterior cardinal slopes but
slightly curved, the latter the longest; anterior end a broad curve;
posterior more produced and more abruptly curved between the
extremities. Beak prominent, somewhat depressed, incurved. Greatest
thickness of shell in the middle. Muscular pits situated above the
middle, oval, profound, connected by the entire pallial impression.
Length 1°18 (100); height -92 (78); thickness °54 (45); length of
anterior end ‘43 (36); of posterior end °75 (63). Length, height and
thickness of largest specimen seen are 1°75 (100); 1°30 (74) and -70
(40); length of anterior end -80 (45); of posterior end -94 (53).
Locality—Marshall.
Revised description.—Slightly opisthogyrate but clearly
prosoclinal, subtriangular, subtumid dimyarians. Anterior
margin broadly and evenly curved, ventral margin gently
curved and posterior border abruptly rounded. Dorsal mar-
gin subrectilinear posterior to the beaks and for a short
distance anterior to the beaks, the two parts of dorsal mar-
gin joining at an angle of approximately 140° below the
beaks.
Beaks placed slightly anterior to mid-length of valves,
prominent, rising well above hinge line. The series of hypo-
types shown in Plate 17, figures 22, 20, 18, 24, appear to
indicate that the opisthogyrate character is more marked in
larger specimens.
Anterior adductor scar prominent, suboval, placed mid-
way between beaks and anterior extremity, adjacent to
anterodorsal margin. A weakly developed radial groove ex-
tends across anterior adductor, joining pallial line ventrally
(PI. 17, fig. 25). Posterior adductor scar sharply defined,
suboval, longer than anterior scar, situated midway between
beak and posterior extremity. Pallial line truncate poste-
monlye(PIE 7) tes).
A number of weakly defined internal ridges present (PI.
17, figs. 17, 18, 24). Extending from the umbonal region
anteroventrally, one ridge lies immediately adjacent to
posterior margin of anterior adductor scar. Posteriorly, a
ridge arising in the umbonal region lies immediately ad-
jacent to the anterior margin of the posterior adductor
scar. Other weaker and less well-defined, gently curving,
internal ridges present on some specimens both above and
below the umbonal ridge.
Dentition strongly developed. Dentition formula (see
Bernard and Munier-Chalmas in Bernard, 1895, pp. 116-
117), of left valve: 4a-2-; of right valve, probably: -3a-3b.
Left valve has strongly developed, triangular, bifid car-
dinal (2) placed directly below beak (PI. 17, fig. 19). This
tooth cleft on ventral, rather than articulating, surface.
Posterior to cardinal 2 a weakly developed elongate socket
is present, merging posteriorly with a flat hinge plate. It is
considered to indicate the presence of cardinal 3b in the
right valve. Directly anterior to cardinal 2 a large triangular
socket for reception of cardinal 3a diverges from beneath
beak. Anterior to this socket a narrow elongate tooth
(4a), diverges from beneath the beak, lies nearly parallel
to the dorsal margin of the valve.
Surface sculpture unknown.
Remarks.—Schizodus sectoralis may be distinguished
from Schizodus rostratus by its less elongate form, its more
nearly central beaks, its less well-developed internal ridges
and musculature, and by its distinctive dentition. S. ros-
tratus is commonly somewhat larger. S. secloralis differs
from S. trigonalis (Herrick) in its less prominent umbonal
104 PALAKONTOGRAPHICA AMERICANA (V, 35)
ridge and abruptly rounded, rather than truncate, posterior
margin.
Types and occurrence.—The right valve collected from
the Marshall sandstone at Marshall, Michigan, and de-
scribed by Alexander Winchell in 1862 (p. 422), holotype,
UMMP, No. 26876, has been illustrated (PI. 17, figs. 14-16) .
The writer here figures as hypotypes three specimens
from the Marshall sandstone at Battle Creek, Michigan,
UMMP, Nos. 44290-44292, and one specimen from Hol-
land, Ottawa County, Michigan, UMMP, No, 35553.
Schizodus sectoralis (Winchell) is known to occur only
in the Marshall sandstone of southern Michigan.
Schizodus triangularis (Herrick)
Plate 18, figures 1-5
?Macrodon ?? triangularis Herrick, 1888, vol. 3, pp. 74-75, pl. 8,
fig. 8.
Schizodus triangularis Herrick, 1888, vol. 4, p. 116, pl. 6, figs. 10, 13;
1895, pl. 17, figs. 10, 13; Lane and Cooper, 1900, p. 264, pl. 11,
figs. 7, 8.
Remarks.—Schizodus triangularis is similar in’ many
respects to Schizodus ehlersi, a species desc ribed for the first
time in the present paper. It may be distinguished by its
shorter relative length, its more anteriorly placed beaks, its
more prominent umbonal ridge, and the presence of a weak
sulcus below the umbonal ridge. Furthermore, the posterior
margin of S. triangularis is subtruncate, forming an obtuse
angle with the dorsal margin. The dorsal and posterior
margins of S$. ehlersi form a gentle curve from the beaks,
little or no angulation being present.
Herrick described and figured specimens considered by
him to be S. triangularis in three publications (1888, vol.
3, pp. 74-75, pl. 8, fig. 8; 1888, vol. 4, p. 116, pl. 6, figs. 10,
13; 1895, pl. 17, figs. 10, 13). A specimen is figured with his
original description which bears a much closer resemblance
to S. ehlersi than to the specimens later figured as S. tri-
angularis. Herrick’s holotype is apparently lost. It is here
questionably included in
because he stated
(1888 vol. 4, p. 116) that ‘The poor specimens encountered
synonymy
last year [and used as a basis for the original description ]
gave an entirely false impression of the species. We have
figured two typical (but, in size, extreme) examples of the
species which show that the specimen figured last year, like
many others seen, had lost the narrow posterior margin.”
Because the holotype cannot be examined, it seems advis-
able to assume the synonymy of this specimen with those
later described by Herrick.
The writer has examined the two hypotypes of S. triangu-
laris described and figured by Lane and Cooper (1900, p.
264, pl. 11, figs. 7, 8), UMMP, Nos. 2227, 2298. Michigan
Geol. Survey, Nos. 19256, 19257. These specimens from the
/
Coldwater formation at Pte. aux Barques lighthouse, Hu-
ron County, Michigan, are refigured in the present paper
(PI. 18, figs. 2-5).
Types and occurrence.—A single specimen, hypotype,
UMMP, No. 44298, is here recorded from the Marshall
sandstone at Battle Creek, Calhoun County, Michigan.
S. triangularis occurs in the Coldwater and Marshall for-
mations of Michigan. In Ohio this species is reported by
Herrick (1888, vol. 4, p. 116) from the Middle Waverly.
Schizodus ehlersi, sp. nov.
Plate 18, figures 6-20
Description.—Subtriangular, prosogyrate, beaks just an-
terior to mid-length. Anterior margin broadly and evenly
curved throughout major extent, somewhat straighter
posteriorly, abruptly rounded at posterior extremity. Pos-
terodorsal margin curves evenly from beaks to meet ventral
margin at posterior extremity. Little or no angulation pres-
ent on this margin. Dorsal border straight anterior to
beaks, joins anterior margin without angulation, forms
angle of approximately 120° with posterodorsal border be-
low beaks. Valves may gape slightly posteriorly.
Umbonal ridge prominent to subrounded, terminates
at posterior extremity, Postumbonal slope variable, com-
monly possesses two radiating grooves and one ridge (PI.
18, figs. 12, 16).
Pallial line prominent, entire, truncate and_ slightly
sinuous posteriorly. Adductor muscle scars prominent. An-
terior scar suboval, marked by radial groove which joins
pallial line ventrally (PI. 18, figs. 6, 7). Posterior adductor
scar slightly larger, suboval, marked with prominent con-
centric sculpture, divisible (on single interior studied) into
two parts; a prominent, deeply recessed anterior portion
and a larger, clearly defined but less deeply impressed,
posterior portion (PI. 18, fig. 8).
Interior of valve marked by weakly defined internal
radial ridges originating in umbonal region (PI. 18, figs. 7,
8). Two slightly more prominent ridges present immedi-
ately adjacent to posterior side of anterior adductor and to
anterior side of posterior adductor (PI. 18, figs. 6-8, 10).
Small pits, irregularly to radially arranged, are reflected
over most of the surface of the single available internal
mold, most common on anterior portion (PI. 18, figs. 6-10) .
These are questionably considered to be of organic origin.
Dentition poorly understood. A single large, subtriangu-
lar, anteriorly inclined cardinal tooth is present inthe
right valve. Posteriorly this cardinal is bounded by a large
triangular socket, and anteriorly by a narrow lanceolate
socket. Other teeth may, or may not, be present in the right
valve. Dentition of left valve unknown.
MISSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLI 105
Remarks.—Schizodus chlersi, known to occur only in the
Marshall sandstone of Michigan, is most closely related to
S. triangularis which occurs in the Marshall sandstone and
the Coldwater shale of Michigan and in the middle Waverly
group of Ohio. Comparison of these two species is made
under remarks on S$. triangularis. Of particular importance
in distinguishing S. ehlersi are its more centrally located
beaks, the evenly and gently curved posterodorsal margin,
and the absence of a sulcus anterior to the umbonal ridge.
Plate 18, figure 9, illustrates a structure present on the
umbonal region of an internal mold of S. chlersi. ‘Vhis
structure, unquestionably of organic origin, is thought to
be the filling of a hole drilled through the valve by a carni-
vorous marine organism.
S. ehlersi is named in honor of G. M. Ehlers, whose
work has contributed greatly to an understanding of the
geology and paleontology of Michigan.
Types and occurrence.—A natural internal mold of a
right valve from the Marshall sandstone at Battle Creek,
Calhoun County, Michigan, UMMP, No. 44299, is here
designated holotype. Paratype, UMMP, No. 44300, is a right
valve from the same locality. Paratypes, UMMP, Nos. 44301
and 44302 are from the Marshall sandstone at Mosherville,
Hillsdale County, Michigan.
Schizodus chlersi is known to occur only in the Marshall
sandstone of southern Michigan.
ORDER HETERODONTA
FAMILY ASTARTIDAE
Genus CYPRICARDELLA Hall, 1858
Cypricardella Hall, 1858a, p. 17 (=Microdon Conrad, 1842, p. 247.
Non Microdon Meigen, 1803; nec Microdon Agassiz, 1833, vol. 2,
pp. 16, 204-205); Hind, 1899, pp. 345-348; Williams and Breger,
1916, pp 239-249; Haffer, 1959, pp. 170-171.
Type species.—By subsequent designation of Miller (1889,
p. 474), Cypricardella subelliptica Hall.
Cypricardella? securis (Winchell)
Plate 15, figures 19-29
Sanguinolites (Cypricardia?) securis Winchell, 1871, pp. 255-256.
Sphenotus aeolus var. curtus Hyde, 1953, pp. 308-309, pl. 39, figs. 2, 3.
Remarks.—This species is questionably referred to Cypyri-
cardella on external characteristics only. No specimens ex-
amined by the writer show the hinge structure. Assignment
to Cypricardella is based on the large escutcheon with
everted edge, the truncate posterior margin, the oblique
umbonal ridge, surface ornamentation and general form.
‘These external characters were emphasized by Hind (1899,
p. 346) in his revised generic description. Hind’s figures of
Cypricardella rectangularis (McCoy) (his pl. 39, figs. 20-26)
show many characters in common with the present species.
Hyde (1953, pp. 308-309) has described Cypricardella?
securis as Sphenotus aeolus var. curtus. The species does
not occur in the Marshall sandstone. The writer has ex-
amined the two specimens which were collected by Rey-
erend H. Herzer from the Waverly group at Newark, Ohio,
and which were described by Winchell in 1871 (pp. 255-
256) (PI. 15, figs. 19-24 of present paper). The two speci-
mens described by Hyde (1953, pp. 308-309) from the
Allorisma winchelli zone at Rushville, Ohio, have also
been examined (PI. 15, figs. 25-29 of present paper). Win-
chell’s specimens from Newark and Hyde's specimens from
Rushville are undoubtedly conspecific and Winchell’s
trivial name, securis, has priority.
Types and occurrence.—Two of Winchell’s primary types
of Cypricardella? securis, from the Waverly group at New-
ark, Ohio, are held at the University of Michigan. Winchell
regarded these as syntypes. Unfortunately neither of them
is as well preserved as those specimens described and fig-
ured by Hyde from Rushville, Ohio. Of Winchell’s two
specimens, the writer here designates UMMP, No. 26742 as
lectotype and UMMP, No. 44175 as paralectotype. Hyde’s
two specimens, OSU, No. 13872 (H-763) , are hypotypes.
Cy pricardella? securis (Winchell) is known to occur only
in the Allensville member of the Logan formation, Waverly
group, at Newark and Rushville, Ohio.
CORRELATION
The segment of the Marshall sandstone pelecypod fauna
which is examined in the present study includes 22 species
belonging to 12 genera. Of these, two species (Schizodus
triangularis and Polidevcia pandoraeformis) are also pres-
ent in the underlying Coldwater shale.
Six of the Marshall species are found in the Cuyahoga
and Logan formations of the Waverly group in southcentral
Ohio. Sanguinolites herricki probably occurs in the Black
Hand member of the Cuyahoga formation. This member
also contains Palaeoneilo concentrica and Prothyris recti-
dorsalis. Forms closely related to Sanguinolites unionifor-
mis and Nuculopsis houghtoni are present in the Black
Hand member. ‘The Byer member of the Logan formation
yields specimens of Schizodus triangularis. In the overlying
Allensville member of the Logan formation Parallelodon
(Cosmetodon) marshallensis and Sphenotus obliquus, as
well as a near relative of Parallelodon (Cosmetodon) sp.
aff. P. ovatus, are present. Palacosolen quadrangularis and
a form closely related to Polidevcia pandoraeformis occur
in the Waverly group but their exact stratigraphic level is
not known.
106
PALAKONVOGRAPHICA AMERICANA (V, 35)
FABLE 3—GEOGRAPHIC AND STRATIGRAPHIC DISTRIBU-
TION OF PELECYPODS. X INDICATES OCCURRENCE; R IN-
DICATES CLOSELY RELATED FORM; ? INDICATES UN-
CERTAIN STRATIGRAPHIC LEVEL OF OCCURRENCE.
North America
Ohio
Or.
Mo.
>
5)
Zz
! ao] n
OG tele Ses
Ce] 0s Oil Olle
4} ns Pp] oa] a
ma fe) non] ol 4
=) a) 1a
« G0 dildi{ uo] o
| € Sat So) Ss
tl 6S Co) nl o}] of o
Sars) =|" olen
. q
Species H|o| a 2 ao] o| Hla
q)y?P) a > Al Od] -d
ow] o n| s > Sis
thy 3 Be Sho HI 51) ll @
Yiol ol] ul o] » FS) Gy || oy 1G)
lA} wo] oO] a] a Sb Sil @
GO] O} Al >] Al A O| Oj} a -A
Py |) | |oe}| | fee) | cee] AMS) | | >
Ctenodonte stella Pla a ee eI
pisariella’ secure Sa le
Xx
ne omaliana omaliana | PXGn | XG XG exe
Grammysia omaliana hydei ee
Nuculopsis houghtoni =
Nuculopsis sectoralis
Palaeoneilo concentrica
Palaeoneilo sulcatina
Palaeoneilo truncata
Palaeosolen frontisocurvus
Palaeosolen quadrangularis QIX?1X?
Earallelodon #9. aff E. 9 CPPCC
X
Parallelodon Spr aid. b. Ovanus
ee Ce
firotuwis ractidoralie Pee
Sanguinolites herricki
Sanguinolites unioniformis
Schizodus ehlersi
Schizodus rostratus
Schizodus sectoralis
SChazZoduisi2e Tsamala s
schizodus triangularis
Se eno EE
Sphenotus obliauus Peet EE EEE
MIsSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLI 107
TABLE 4—DISTRIBUTION OF CERTAIN PELECYPODS IN THE MARSHALL FORMATION OF MICHIGAN.
Locality
Species
Kent Co.
HainiicdallemiCor
RMNGAALoeS Fes ee eae
Holland
Richtee Ime a SSS
Marshall
Moscow
Mosherville
Napoleon
Najxolkeoia tas Jit, eke
Ctenodonta stella
Grammysia omaliana omaliana
Nuculopsis houghtoni
tas
Nuculopsis sectoralis
Palaeoneilo concentrica
Palaeoneilo sulcatina
Palaeosolen frontisocurvus
Palaeosolen quadrangularis
Parallelodon marshallensis
Parallelodon sp. aff. P. ovatus
Polidevcia pandoraeformis
Prothyris rectidorsalis
Sanguinolites herricki
Sanguinolites unioniformis
Schizodus ehlersi
Schizodus rostratus
Schizodus sectoralis
Schizodus? similis
Schizodus triangularis
Solenomorpha dorsocurva
Solenomorpha scalpriformis
ophenotus obliquus
108 PALAEONTOGRAPHICA AMERICANA (V, 35)
None of the Marshall species studied, or closely related
forms, occur in the Waverly group above the Allensville
member of the Logan formation or below the Black Hand
member of the Cuyahoga formation. In the rocks including
and between these two members, 50 per cent of the Mar-
shall species, or closely related forms, are present. One may
conclude that the Marshall sandstone of southern Michi-
gan may tentatively be considered a time equivalent of
rocks between the base of the Black Hand member and the
top of the Allensville member in the Waverly group of
southern and central Ohio,
A detailed correlation between the Marshall sandstone
of Michigan and the Waverly group of Ohio is not possible
at the present time. Although the localities of the specimens
studied are known, the stratigraphic relationship between
the strata exposed at these localities is yet to be determined.
Two of the species from the Marshall formation have a
geographic range extending beyond Michigan and Ohio.
Palaconeilo concentrica occurs in the Pocono sandstone of
Pennsylvania as well as in the Black Hand member of the
Cuyahoga formation in Ohio and the Marshall sandstone
in Michigan.
Under the name Grammysia omaliana omaliana are
erouped a number of previously distinct species from the
Marshall sandstone of Michigan, the Kinderhook of Iowa,
the Northview siltstone of Missouri, the lower Carbonifer-
ous of Nevada, the Carboniferous limestone of Northum-
berland, England, and the lower Carboniferous of Derby-
shire, England. The shells here considered as G. omaliana
omaliana are of such a generalized form and of such
variable character that, despite the suspicion that more
than one zoologic species is present, morphologic criteria
for speciation could not be established. Correlation on the
basis of such a generalized pelecypod is tenuous at best.
‘Table 3 shows the geographic and stratigraphic distribu-
tion of the pelecypods studied. Table 4 shows the geo-
graphic occurrence of species within the Marshall sand-
stone of Michigan.
AGE OF THE MARSHALL SANDSTONE
The age of the Marshall sandstone remains in question.
Various opinions as to whether the Marshall is Kinder-
hookian, Osagean, or intermediate between these two have
appeared in the literature. The Mississippian Subcommittee
of the Committee on Stratigraphy of the National Research
Council (Weller, et al., 1948, chart opposite p. 188) placed
the Napoleon sandstone (upper Marshall) in the Osagean
and the lower Marshall in the Kinderhookian. Monnett
(1948, p. 630) considered the entire Marshall sandstone to
be Kinderhookian and the overlying Michigan formation
to be lowermost Osagean. Cohee, Macha, and Holk (1951)
believed the entire Marshall and part of the Coldwater
formation are Osagean, a view which is in part substan-
tiated by the work of Miller and Garner (1955, pp. 114-
120). The latter writers, however, have shown that Kinder-
hookian as well as Osagean faunal elements are present in
the Marshall formation.
Pelecypods of the Marshall sandstone show a close af-
finity with those of the upper part of the Cuyahoga forma-
tion and with the Logan formation of the Waverly group
in southcentral Ohio (see section on correlation). Weller,
et al., (1948) date the upper part of the Cuyahoga forma-
tion and the entire Logan formation as Osagean. The Kin-
derhookian-Osagean boundary within the Cuyahoga for-
mation is not, however, well established.
The present study lends supporting evidence to the opin-
ion of Miller and Garner (1955, pp. 114-120) that, al-
though Kinderhookian faunal elements are present in the
Marshall sandstone, the majority of available evidence in-
dicates that the Marshall is largely of Osagean age.
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Monnett, V. B.
1948. Mississippian Marshall formation of Michigan. Bull.
Amer. Assoc. Petroleum Geol., vol. 32, No. 4, pp. 629-
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Miller, Johannes
1842. Beobachtung tiber die Schwimmblase der Fische, mit
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Murchison, Robert I., Verneuil, Philippe Edouard P. de, and
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Oehlert, D. P.
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Paul, H.
1941. Fossilium Catalogus, Pars 91, Lamellibranchiata In-
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Potter, P. E., and Pryor, W. A.
1961. Dispersal centers of Paleozoic and later clastics of the
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Quenstedt, Werner
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Safford, J. M.
1869. Geology of Tennessee. Nashville, Tennessee, S. C. Mer-
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Salter, J. W.
1852. Notes on the fossils above mentioned, from the Ottawa
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1934. Classification of nuculid pelecypods. Bull. du Musée
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1822. Das Thierreich eingetheilt nach dem Bau der Thiere
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1916. The fauna of the Chapman sandstone of Maine, includ-
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1865. Descriptions of new species of fossils, from the Marshall
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1890. Palaeontology of Illinois, description of fossil inverte-
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1885. Handbuch der Palaeontologie. Abtheilung. Bd. II, Mol-
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Verlag von R. Oldenbourg, 893 pp.
18
|
PLATES
Note: On plate headings read Plate for Page
114
Figure
1-18.
30-33.
34-36.
PALAEONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE 7
Gtenodonta: stella \(Winchrelli) i cccrecstcecscenssevcavescvccrcecexsssvesstcectasortarexresceteteeressnexanes-teeatarcunansnananans
1, 2, 3 (right). Internal mold of left valve, lectotype, UMMP, No. 37673, from
Marshall sandstone at Battle Creek, Mich. 1. Lateral view, X4.8. 2. Lateral
view of umbonal region, X12. 3. (Right), lateral view, X1.2.
3 (Left). Lateral view of mold of right valve, paralectotype, UMMP, No. 37674,
from Marshall sandstone at Battle Creek, Mich.; X1.2.
4, 5 (Lower). Internal mold of left valve, paralectotype, UMMP, No. 37679, from
Marshall sandstone at Battle Creek, Mich. 4. Lateral view, X4.8. 5. (Lower), lateral
view, X1.2.
5 (upper). Lateral view of internal mold of right valve, paralectotype, UMMP,
No. 37680, from Marshall sandstone at Battle Creek, Mich., X1.2.
6, 7. Internal mold of left valve, paralectotype, UMMP, No. 37682, from Marshall
sandstone at Battle Creek, Mich. 6. Lateral view, X1.2. 7. Lateral view, X4.8.
8-11. Right valve, hypotype, UMMP, No. 37709, from Marshall sandstone at
Marshall, Calhoun Co., Mich. 8. Anterior view, X4.8. 9. Lateral view, X4. 10.
Lateral view, X1.2. 11. Dorsal view, X4.8.
12-14. Right valve, hypotype, UMMP, No. 37707, from Marshall sandstone at
Marshall, Calhoun Co., Mich. 12-13. Dorsal and lateral views, X4.8. 14. Lateral
view, X1.2.
15, 16. Left valve, paralectotype, UMMP, No. 37693, from Marshall sandstone at
Battle Creek, Mich. Anterior and lateral views, X4.8.
17. Lateral view of internal mold of umbonal region of left valve, paralectotype,
UMMP, No. 37704, from Marshall sandstone at Marshall, Calhoun Co., Mich. X12.
18. Latex cast of hinge line of specimen illustrated in figs. 1-3. Lectotype, UMMP,
No. 37673, from Battle Creek, Michigan. X12.
Nuculopsis iowensis (White amd Whitfield) ...c.cccccccssccssesssseecsssessescesseseseeesnensaneecensecanee
19, Latex cast of hinge line of specimen illustrated in figs. 20-22, X12. Note the
poorly preserved chondrophore.
20-22, Natural internal mold of right valve, hypotype, UMMP, No. 44007, from bed
No. 5, Kinderhook, at Burlington, Ia. Anterior, dorsal, and lateral views, X2.4.
23-25. Natural internal mold of left valve, hypotype, UMMP, No. 44006, from bed
No. 5, Kinderhook, at Burlington, Ia. Dorsal, lateral, and posterior views, X2.4.
26. Lateral view of natural internal mold of left valve, hypotype, UMMP, No. 44009,
from bed No. 5, Kinderhook, at Burlington, Ia. X2.4.
27, 28. Natural internal mold of right valve, hypotype, UMMP, No. 44005, from bed
No. 5, Kinderhook, at Burlington, Ia. Lateral and dorsal views, X2.4.
29, Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
44008, from bed No. 5, Kinderhook, at Burlington, Ia. X2.4.
Niculopsis Sp. ssssccccscsccsscrecsecsersesvocossssssescesnssysoncsasscssasouecdetuesuecuensettersensosustectettecsrsnanserscceeszersenuerscns
30. Latex cast of hinge line of right valve, UMMP. No. 44030, from the Waverly
at Medina, O. X12. Note prominent chondrophore.
31-33. Natural internal mold, UMMP, No. 44029, from the Waverly group at
Medina, O. Posterior, dorsal, and right lateral views, X2.4. Note prominent
muscle scars.
Nuculopsis sectoralis (Winchell)
34. An illustration drawn by Alexander Winchell of a specimen from Battle Creek,
Mich., hypotype, UMMP, No. 44015. X1.2.
35. An illustration drawn by Alexander Winchell. X1.2. Note that the identification,
which is in Winchell’s handwriting, is not certain and that the illustration is nearly
identical in outline with that shown in fig. 34. 7
36. Lateral view of large left valve from the Marshall sandstone at Battle Creek,
Mich. X1.2. This specimen, AMNH, No. 6539/1, was described by Hall (1885, Pl. 45,
fig. 29) as Nucula houghtont.
77
78
76
PALAEONTOGRAPHICA AMERICANA, VOL. V
116
Figure
1-12.
PALAEONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE 9
All figures X1.2 except as noted.
Page
aI. Generis (KGS AGL)” Sosceecenn-noccccoso-ponceccocccennccene cer seberpacecoocae cea. cuanscceceoareoceeceecoaconcecece
1-3. Natural internal mold of right valve, neotype, UMMP, N. 43870, from
Marshall sandstone at Battle Creek, Calhoun Co., Mich. Dorsal, anterior, and
lateral views.
4, 5. Latex cast of internal mold of right valve shown in figs. 1-3. 4. Lateral view.
5. Anterior portion of hinge line showing striations on taxodont teeth, X12.
6. Latex cast on internal mold of hinge line, hypotype, UMMP, No. 43871, from
Marshall sandstone at Battle Creek, Calhoun Co., Mich. X2.4.
7-9. Right valve, hypotype, UMMP, No. 43877, from Marshall sandstone, SE. 1%,
S. 14, Sec. 19, Liberty Twp., Jackson Co., Mich. 7, 8. Lateral and dorsal views.
9. Surface of valve, X4.8.
10. Lateral view of left valve, hypotype, UMMP, No. 43872, from Marshall sand-
stone at Moscow, Hillsdale Co., Mich.
11. Latex cast of natural internal mold shown in fig. 12.
12. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
43873, from Marshall sandstone at Waverly Quarry, 1 mile N. E. of Holland, Mich.
Palaconeilo: concentrica ((Wanchtell))) ceccsccsscceccess-cescnacsessoteceszesccucvsreccvecccrocessossaceoronteneontyeeuscceese
13-15. Left valve, lectotype, UMMP, No. 37334, from Marshall sandstone at Jones-
ville, Hillsdale Co., Mich. Dorsal, lateral and anterior views.
16. Lateral view of left valve, hypotype, UMMP, No. 35427, from Marshall sand-
stone at Hillsdale, Hillsdale Co., Mich.
17. Lateral view of left valve with dorsal part removed to show dentition, hypotype,
UMMP, No. 43875, from Marshall sandstone at Mosherville, Mich.
18. Lateral view of left valve, hypotype, UMMP, No. 27756, from Marshall sand-
stone at Germain’s Quarry, Hillsdale Co., Mich.
19. Lateral view of right valve, hypotype, UMMP, No. 35427A, from Marshall
sandstone at Hillsdale, Hillsdale Co., Mich.
20. Lateral view of right valve, hypotype, UMMP, No. 26886, from Marshall sand-
stone at Alan’s Quarry, Hillsdale Co., Mich.
21, 22. Left valve, shell partially removed, hypotype, UMMP, No. 43874, from
Marshall sandstone at Mosherville, Mich. Dorsal and lateral views.
23. Latex cast of natural internal mold of hinge line of specimen shown in figs. 21,
22. X2.4.
24, 25. Right valve, hypotype, UMMP, No. 43061, from Marshall sandstone at
Germain’s Quarry, Hillsdale Co., Mich. 24. Lateral view. 25. Valve surface, X4.8.
26-29. Left valve with shell partially removed, hypotype, UMMP, No. 43876, from
Marshall sandstone, probably at Battle Creek, Mich. 26. Lateral view. 27. Valve
surface, X4.8. 28, 29. Anterior and dorsal views.
70
71
PALAEONTOGRAPHICA AMERICANA, VOL. V
Page 10
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-15.
16-34.
35, 36.
MISSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLL
EXPLANATION OF PLATE 10
All figures X1.2, except as noted.
Ralaeonetlowsiruncata: Elalll cts sccccccsceerectr eaters tt svar oases
1. Lateral view of right valve, syntype, AMNH, No. 6546/1, from the Waverly
group at Newark, O. Hall (1885, pl. 50, fig. 41) illustrated this specimen.
2, 3. Latex cast of natural internal mold of left valve shown in fig. 4. 2. Hinge,
X4.8; note that taxodont teeth are straight rather than chevron-shaped immedi-
ately anterior to umbo. 3. Lateral view.
4. Lateral view of left valve, hypotype, UMMP, No. 43878, from glacial drift
(probably Coldwater formation) at Kalamazoo, Mich. Note truncation of pallial
line posteriorly.
5. Oblique view of anterior portion of latex cast shown in figs. 2 and 3, X4.8. Note
strongly marked adductor muscle scar and lanceolate accessory muscle scar
immediately behind and above the adductor.
6-8. Natural internal mold of right valve, hypotype, UMMP, No. 43879, from
glacial drift (probably Coldwater formation) at Kalamazoo, Mich. Dorsal,
anterior, and lateral views.
9-11. Natural internal mold of left valve, hypotype, UMMP, No. 43957, from
glacial drift (probably Coldwater formation) at Kalamazoo, Mich. Lateral,
dorsal, and anterior views.
12-14. Natural internal mold of left valve, hypotype, UMMP, No. 43958, from
glacial drift (probably Coldwater formation) at Kalamazoo, Mich. Lateral view
showing large adductor scar; anterior and dorsal views.
15. Latex cast of hinge line of right valve, hypotype, UMMP, No. 43956, from
glacial drift (probably Coldwater formation) at Kalamazoo, Mich., X4.8. Taxo-
dont teeth near both the anterior and posterior extremities are chevron-shaped.
Rolideuctarspand o7,acfonmss a (Stevens) trrcrcetcte-eeece- cose neettneeeereeter eee eteecenteeeseaeeeee eres
16. Lateral view of natural internal mold of right valve, UMMP, No. 44064,
from glacial drift (probably Coldwater formation) at Kalamazoo, Mich.
17. Lateral view of left valve, hypotype, UMMP, No. 29465, from Marshall
sandstone at Moscow, Hillsdale Co., Mich. This specimen was described but not
figured by Winchell (1862, p. 419) as Leda bellistriata.
18. Lateral view of natural internal mold of right valve, UMMP, No. 44066,
from glacial drift (probably Coldwater formation) at Kalamazoo, Mich.
19-21. Right valve, lectotype, UMMP, No. 44059, from Marshall sandstone at
Mosherville, Mich. Dorsal, anterior, and lateral views.
22-25. Right valve, hypotype, UMMP, No. 44060, from Marshall sandstone at
Mosherville, Mich. 22, 23. Lateral and dorsal views. 24. Oblique dorsal view
of escutcheon and dorsal margin of valve posterior to beak, X4.8; note undulations
in escutcheon which reflect teeth and sockets, the weak ridge bounding the
escutcheon, and the irregular striations subparallel to hinge line between umbonal
ridge and valve margin. 25. Lateral view of surface sculpture, X12.
26. Lateral view of left valve, hypotype, UMMP, No. 44063, from Marshall
sandstone at Moscow, Mich.
27. Latex cast of hinge line of natural internal mold of right valve shown in
fig. 28, hypotype, UMMP, No. 44062, from Marshall sandstone at Marshall,
Calhoun Co., Mich., X4.8. Note poorly preserved resilifer below beak and indi-
cations of teeth passing above this structure.
28. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
44062, from Marshall sandstone at Marshall, Calhoun Co., Mich.
29-31. Natural internal mold, hypotype, UMMP, No. 27053, from Marshall sand-
stone at Germain’s quarry, Hillsdale Co., Mich. Anterior view showing that
valves are not entirely closed; dorsal and lateral views of right side.
32. Lateral view of posterior part of left valve, hypotype, UMMP, No. 27762,
from Marshall sandstone at Battle Creek, Calhoun Co., Mich. This specimen
was described but not figured by Winchell (1862, p. 419) as Leda sp.
33. Oblique view of umbonal region of natural internal mold of left valve,
UMMP. No. 44065, from glacial drift (probably Coldwater formation) at
Kalamazoo, Mich., X12. Note weak accessory muscle scars extending posteroven-
trally.
34. Lateral view of left valve, hypotype, UMMP, No. 44061, from Marshall
sandstone at Mosherville, Mich.
Polidevcia sp. S
35. Lateral view of right valve, UMMP, No. 26731, from Hickman or Maury
County, Tenn. This specimen was described but not figured by Winchell (i
Safford, 1869, p. 444) as Leda bellistriata?
36. Lateral view of right valve, UMMP, No. 26731, from Hickman or Maury
County, Tenn. This specimen was described but not figured by Winchell (77
Safford, 1869, p. 444) as Leda bellistriata?
79
80
118
Figure
1-9.
10-33.
PALAEKONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE I1
All figures X1.2, except as noted.
Prothyris rectidorsalis (Winchell) .........-...:sessse---cscesseerssenssesenenecnevenencscesscnsssscsususivensnsusnerse
1-5. Left valve, neotype, UMMP, No. 36825, from Marshall sandstone at Marshall,
Calhoun Co., Mich. 1, 2. Lateral and anterior views. 3. Oblique lateral view of
anterior portion of valve, X4.8, showing anterior ridge, associated notch in anterior
border, and faint radial sculpture on valve surface. 4+. Dorsal view, 5. Surface
ornamentation on posterior part of valve, X12; note semireticulate pattern due to
radial and concentric sculpture.
6, 7. Natural internal mold of right valve, hypotype, UMMP, No. 37297, from
Marshall sandstone at Moscow, Hillsdale Co., Mich. Dorsal and lateral views.
8, 9. Right valve, hypotype, UMMP, No. 43058, from glacial drift (probably
Marshall sandstone) at Grass Lake, Jackson Co., Mich. Lateral and anterior
views.
Sanguinolites untontporeets) VVinchelllll ers .cenrsecer-c-csz-sesnescreoueenaceeesnstencecstseeaceneaeantarceerseccaseons
10-12. Left valve, lectotype, UMMP, No. 26899, from the Marshall sandstone at
Moscow, Hillsdale Co., Mich. This specimen was chosen as lectotype from Win-
chell’s 2 syntypes of the species. 10. Lateral view of hinge line, X4.8; the dark
shadowed area parallel to dorsal margin is caused by overhanging valve above
escutcheon. 11-12. Dorsal and lateral views.
13-15. Left valve, hypotype, UMMP, No. 44168, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. Posterior portion of valve shows exterior, anterior
portion is natural internal mold. Lateral view, showing prominent depression,
representing strong ridge, immediately behind anterior adductor; anterior and
dorsal views.
16-18. Natural internal mold of left valve, paralectotype, UMMP, No. 44166, from
the Marshall sandstone at Moscow, Hillsdale Co., Mich. Dorsal, lateral, and
anterior views.
19-21. Natural internal mold of left valve, hypotype, UMMP, No. 44171, from the
Marshall sandstone at Battle Creek, Calhoun Co., Mich. 19, 20. Lateral and dorsal
views. 21. Lateral view of anterior portion of mold, X4.8.
22-24. Right valve, hypotype, UMMP, No. 44169, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. 22. Dorsal view. 23. Lateral view of hinge line, X4.8;
the darkly shadowed horizontal line represents overhang of shell above escutcheon.
24. Lateral view.
25-27. Hypotype, UMMP, No. 44172, from the Marshall sandstone at Battle Creek,
Calhoun Co., Mich. Anterior, dorsal, and left lateral views.
28-31. Left valve, hypotype, UMMP, No. 44168, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. 28. Surface of valve, X12. 29-31. Dorsal, anterior, and
lateral views.
32, 33. Natural internal mold with part of shell material preserved along hinge
line, hypotype, UMMP, No. 44170, from the Marshall sandstone at Battle Creek,
Calhoun Co., Mich. 32. Lateral view. 33. Dorsal view of shell along hinge line,
X4.8; note the sharply defined, narrow, lanceolate escutcheon,
84+
PALAEONTOGRAPHICA AMERICANA, VOL. V Page 11
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-19.
MISSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLL
EXPLANATION OF PLATE {2
All figures X1.2, except as noted.
MMB ROHAG CHIRGTEIG, (OMICS), pxcrcscocesosnsocence eee encceerpccncen senectonnbosbacococpocbeosesccneuceeackace ScAceEROACERBD ICRA
1-5. Right valve, hypotype, UMMP, No. 44073, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. 1. Dorsal view of escutcheon illustrating deeply incised
groove subparallel to valve margin, X4.8. 2, 3. Dorsal and lateral views. +. Surface
adjacent to ventral margin on posterior part of valve, X12; note the linear series
of nodes and the very fine ridges between them which connect nodes of adjacent
series. 5. Lateral view of posterior portion valve, X4.8; note the four crenulated
ridges and the absence of nodes on the dorsal part of the postumbonal slope.
6-9. Right valve, natural internal mold with part of shell material preserved along
hinge line, hypotype, UMMP, No. 44072, from the Marshall sandstone at Battle
Creek, Calhoun Co., Mich. 6. Dorsal view; note clearly defined groove in escutcheon.
7. Lateral view of natural internal mold of anterior adductor muscle scar, X4.8. 8, 9.
Anterior and lateral views.
10-12. Left valve, hypotype, UMMP, No. 44077, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. Dorsal, anterior, and lateral views.
13. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
44074, from the Marshall sandstone at Marshall, Calhoun Co., Mich.
14. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
44071, from the Marshall sandstone at Battle Creek, Calhoun Co., Mich.
15, 16. Natural internal mold of right valve, hypotype, UMMP, No. 44075, from the
Marshall sandstone of Hillsdale Co., Mich. 15. Dorsal view; note the deep groove
present in position of escutcheon on internal mold. 16. Lateral view.
17. Lateral view of natural internal mold of right valve, hypotype, OSU, No. 13783
(12617), from the Allensville member, Logan formation, at Newark, O. This speci-
men was illustrated by J. E. Hyde (1953, pl. 39, fig. +).
18, 19. Natural internal mold of left valve, UMMP, No. 26747, from the Marshall
sandstone at Hillsdale, Hillsdale Co., Mich. Dorsal and lateral views. This is the
only known speciment of Sanguinolites naiadiformis Winchell. It is here considered
as probably synonymous with Sphenotus obliquus (Meek).
Page
85
119
120
Figure
1-11.
15-23.
PALAEONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE 13
All figures 1.2, except as noted.
Palacosolen quadrangularis (Wiimchel])) ........:..:.sccsssssesccsssersnsseeecseeecscsneneeeerecceecececeececeseccse
1, 2. Latex cast of natural internal mold of right valve shown in figs. 3 and 4,
hypotype, UMMP, No. 37298, from the Marshall sandstone at Battle Creek, Mich.
1. Lateral view. 2. Umbonal region showing striated adductor muscle scar and
dentition, X4.8.
3, 4. Natural internal mold of right valve, hypotype, UMMP, No. 37298, from the
Marshall sandstone at Battle Creek, Mich. Lateral and dorsal views.
5, 6. Natural internal mold of left valve, lectotype, UMMP, No. 26893A, from the
Marshall sandstone at Marshall, Mich. Lateral and dorsal views.
7. Lateral view of natural internal mold of right valve, paralectotype, UMMP, No.
26893B, from the Marshall sandstone at Marshall, Mich.
g. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
36809, from the Marshall sandstone at Battle Creek, Mich.
9. Lateral view of natural internal mold of left valve, hypotype, UMMP, No. 36826,
from the Marshall sandstone at Marshall, Mich., showing an immature individual.
10, 11. Right valve, hypotype, UMMP, No. 37300, from the Marshall sandstone at
Marshall, Mich. 10. Portion of external surface of valve showing fine surface
striae, X12. 11. Lateral view illustrating thin shell which partially covers natural
internal mold.
Palacosolen frontisOCUrvus, SP. MOV. cecccccccccrsreerecrserereeseerees
12-14. Left valve, holotype, UMMP, No. 37302, from the Marshall sandstone at
Battle Creek, Mich. 12. External surface of valve, X4.8. 13. Lateral view illustrating
thin shell which partially covers natural internal mold, and weak lines radiating
posteroventrally from umbo. 14. Dorsal view.
Solenomorpha scalpriforanas, ((NWinchelll))) Vee-.-ctcccqccsssscs-arnesrercesessstonccrneaemeeceedevenpersers caecnencsrs=ersr=
15. Portion of external surface of right valve, hypotype, UMMP, No. 37315, from the
Marshall sandstone at Marshall, Mich., X4.8.
16. Lateral view of natural internal mold of right valve, hypotype, UMMP, No.
37313, an immature individual from the Marshall sandstone at Marshall, Calhoun
Co., Mich.
17, 18. Natural internal mold of a right valve, lectotype, UMMP, No. 26894, from
the Marshall sandstone at Marshall, Mich. Dorsal and lateral views.
19, 20. Latex cast of lectotype, UMMP, No. 26894, an internal mold of a right valve
from the Marshall sandstone at Marshall, Mich. 19. Lateral view. 20. Umbonal
region showing striated adductor scar and dentition, X4.8.
21, 22. Natural internal mold of right valve, paralectotype, UMMP, No. 36811, from
the Marshall sandstone at Marshall, Mich. Dorsal and lateral views.
23. Lateral view of right valve, hypotype, UMMP, No. 37314, from the Marshall
sandstone at Marshall, Mich., illustrating thin shell partially covering the natural
internal mold.
Solenomorpha dorsocurva, Sp. NOV. cece
24-26. Natural internal mold of left valve, holotype, P, No. , from the
Marshall sandstone at Marshall, Calhoun Co., Mich. 24, 25. Dorsal and lateral
views. 26. Lateral view of latex cast of holotype, illustrating interior of umbonal
region and partially preserved dentition, X4.8.
90
87
88
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA
AMERICANA, VOL. V
EEE avr
MIssIssIPPIAN DIMYARIAN PELECYPODS; DRISCOLL 121
EXPLANATION OF PLATE [4
All figures X1.2.
Grammysanonaltananomaliana, ((dewikXominck in peenccee csc cetee cet eee teeters eer 91
Fig. 1. Lateral view of left valve, hypotype, Sedgwick Mus. Nat. History, No. E. 1068,
from the Carboniferous limestone at Lowick, Northumberland, England. This is a
syntype of Sanguinolites variabilis McCoy.
2-4. Left valve, hypotype, UMMP, No. 37611, from the Marshall sandstone at
Fayette quarry, Hillsdale Co., Mich. Dorsal, anterior, and lateral views.
5-7. Right valve, hypotype, BMNH, No. L. 46454, from the Lower Carboniferous,
Visean D zone, at Thorpe Cloud, Derbyshire, England. Anterior, lateral, and dorsal
views.
8. Lateral view of left valve, hypotype, Sedgwick Mus. Nat. History, No. E. 1073,
from the Carboniferous limestone at Lowick, Northumberland, England. Described
by McCoy (1855, p. 508) as Sanguinolites variabilts.
9. Lateral view of right valve, hypotype, UMMP, No. 1486, from the Yellow sand-
stone, Kinderhook group, at Burlington, Ia.
13, 14. Right valve, hypotype, BMNH, No. L. 46461, from the Lower Carboniferous,
Visean D zone, at Thorpe Cloud, Derbyshire, England. Lateral and dorsal views.
15. Lateral view of left valve, hypotype, AMNH, No. 6570/1, from the Yellow
sandstone, Kinderhook group, at Burlington, Ia. This specimen is a syntype of
Grammysia plena Hall (1885, pp. 382-383, pl. 61, fig. 31).
19-21. Right valve, hypotype, UMMP, No. 1486, from the Yellow sandstone, Kinder-
hook group, at Burlington, Ia. Lateral, dorsal, and anterior views.
22. Lateral view of left valve, hypotype, Sedgwick Mus. Nat. History, No. E. 1071,
from the Carboniferous Limestone, at Lowick, Northumberland, England. This speci-
men was described and figured by McCoy (1855, p. 508) as Sanguinolites variabilis.
23. Lateral view of latex cast of left valve, hypotype, UMMP, No. 35715, from the
Marshall sandstone at Alan’s quarry, Hillsdale Co., Mich. This specimen is a syntype
of Sanguinolites hannibalensis Winchell (1865, p. 128).
24. Lateral view of left valve, hypotype, USNM, No. 47334, from the Kinderhook
group at Burlington, Ia.
27-29. Left valve, hypotype, BMNH, No. P.L. 3583, from the Lower Carboniferous,
Visean D zone, at Thorpe Cloud, Derbyshire, England. Lateral, dorsal, and anterior
views.
30-32. Left valve, hypotype, Sedgwick Mus. Nat. History, No. E. 1074, from the
Carboniferous Limestone at Lowick, Northumberland, England. This specimen was
described by McCoy (1855, p. 508) as Sanguinolites variabilis. Lateral, anterior, and
dorsal views.
33. Lateral view of right valve, hypotype, UMMP, No. 1486, from Yellow sandstone,
Kinderhook group, at Burlington, Ia.
34, 35. Right valve, hypotype, BMNH, No. L. 46463, from the Lower Carboniferous,
at Thorpe Cloud, Derbyshire, England. Lateral and dorsal views.
36. Lateral view of right valve, hypotype, UMMP, No. 1486, from Yellow sandstone,
Kinderhook group, at Burlington, Ia.
37-39. Left valve, hypotype, AMNH, No. 6570/1, from Yellow sandstone, Kinderhook
group, at Burlington, Ia. This specimen is a syntype of Grammysia plena Hall (1885,
pp. 382-383, pl. 61, fig. 32). Dorsal, lateral, and anterior views.
42-44. Left valve, hypotype, USNM, No. 14384, from the lower Carboniferous on east
slope of small hill on east side of Secret-canon-road, Eureka District, Nevada, Loc.
No. 655. This specimen described by Walcott (1884, p. 244) as Grammysia hannibal-
ensis. Lateral, anterior, and dorsal views.
45. Lateral view of right valve, hypotype, BMNH, No. P.L. 3586, from the Lower
Carboniferous, Visean D zone, at Thorpe Cloud, Derbyshire, England.
(GATTO SUCHIO LCL CIUCOM RI CCT WS 1L US) Pop ILO Ueapecssenceesesssrccessoneseccnsnartnerseecieeesnceccstanseseisneneeenanscetrsececaertasn cca 98
Figs. 10-12. Right valve, paratype, UMMP, No. 37322, probably from the Coldwater
formation. Collected from glacial drift in Michigan. Lateral, anterior, and dorsal
views.
16-18. Left valve, paratype, UMMP, No. 37329, probably from the Coldwater forma-
tion. Collected from glacial drift in Michigan. Dorsal, anterior, and lateral views.
25, 26. Left valve, holotype, UMMP, No. 37328, probably from the Coldwater forma-
tion. Collected from glacial drift in Michigan. Lateral and dorsal views.
40, 41. Left valve, paratype, UMMP, No. 37326, probably from the Coldwater for-
mation. Collected from glacial drift in Michigan. Dorsal and lateral views.
122
Figure
1-18.
19-29.
30-39.
40-48.
PALAEONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE 15
All figures X1.2, except as noted.
Page
Sanguinolites? Wersickty Spee 0 Useunirwreriie nai cuenuewe nce Stee e ere nao
1-4. Natural internal mold of right valve, holotype, UMMP, No. 43048, from the
Marshall sandstone at Holland, Ottawa Co., Mich. 1. Dorsal view, X2.4. 2. Oblique
view of anterior portion of mold, X2.4; note anterior adductor and accessory muscle
scars. 3. Lateral view, X2.4. 4. Lateral view.
5-8. Natural internal mold of right valve, paratype, UMMP, No. 43052, from the
Marshall sandstone at Holland, Ottawa Co., Mich. 5. Lateral view, X2.4. 6. Lateral
view; note the prominent umbonal ridge and broad postumbonal slope. 7, 8. Anterior
and dorsal views.
9-11. Natural internal mold of right valve, paratype, UMMP, No. 31717, from the
Marshall sandstone at Battle Creek, Calhoun Co., Mich. This valve, less typical
than others here illustrated, is thought to show variation within the species.
Dorsal, lateral, and anterior views.
12, 13. Natural internal mold of right valve, paratype, UMMP, No. 43050, from
the Marshall sandstone at Holland, Ottawa Co., Mich. 12. Lateral view. 13.
Anterior view, X2.4.
14-17. Natural internal mold of right valve, paratype, UMMP, No. 43053, from the
Marshall sandstone at Holland, Ottawa Co., Mich. 14. Oblique view of anterior por-
tion of mold, X4.8; note anterior adductor and accessory muscle scars. 15, 16.
Anterior and dorsal views. 17. Lateral view, X2.4; note that anterior thickened area
of valve, is particularly well reflected in this specimen.
18. Lateral view of natural internal mold of left valve, paratype, UMMP, No.
37351, from the Marshall sandstone at Battle Creek, Calhoun Co., Mich.
Gypricardella2 ssc curtsm (OWinchelli)y cecesrecctteeeretererc ceca ececcoat terete neceeractence cere aetas errno aes
19-21. Lectotype, UMMP, No. 26742, from the Waverly group at Newark, O. Right
lateral, dorsal, and anterior views.
22-24. Paralectotype, UMMP, No. 44175, from the Waverly group at Newark, O.
Dorsal, right lateral, and anterior views.
25, 26. Hypotype, OSU, No. 13782, from the Allorisma winchelli zone, Allensville
member, Logan formation, Waverly group, at Rushville, O. This specimen was fig-
ured by Hyde (1953, pl. 39, fig. 2) as a paratype of Sphenotus acolus var. curtus
Hyde [—Cypricardella? securis (Winchell) ] Right lateral and dorsal views.
27-29. Hypotype, OSU, No. 13782, from the Allorisma winchelli zone, Allensville
member, Logan formation, Waverly group, at Rushville, O. This specimen was
figured by Hyde (1953, pl. 39, fig. 3) as the holotype of Sphenotus acolus var.
curtus Hyde [=Cypricardella? securis (Winchell) ]. Right lateral, anterior, and
dorsal views.
Parallelodon (Gosmetodon)) sps att. (P. ovatias) (alll) sro ececcsescetecceezescneneeresesestemeneseectee
30-32. Natural internal mold of right valve, UMMP, No. 37402, from the Marshall
sandstone at Battle Creek, Calhoun Co., Mich. Lateral, anterior, and dorsal views.
33-35. Natural internal mold of right valve, UMMP, No. 37403, from the Marshall
sandstone at Marshall, Mich. Lateral, dorsal, and anterior views.
36-39. Natural internal mold of left valve, UMMP, No. 37401, from the Marshall
sandstone at Battle Creek, Calhoun Co., Mich. 36. Lateral view, 37. Lateral
view of latex cast of hinge line, X4.8; note that only two posterior lateral teeth
are present in this valve. 38. Dorsal view. 39. Lateral view of anterior portion of
latex cast shown in fig. 37, X12; note the two small nodelike teeth.
Parallelodor spencers eres Peas Meseuedeassuecs Cenereeacasce hecteae re era EE eRe eae EeaES
40-43. Left valve showing external ornamentation and natural internal mold of hinge
line, UMMP, No. 44271, probably from the Coldwater formation, locality unknown.
40-42. Dorsal, lateral, and anterior views. 43. Lateral view of posterodorsal portion
of valve, X4.8; note the natural mold of three posterior Jateral teeth and the evenly
spaced concentric ornamentation.
44-47. Natural internal mold of left valve, UMMP, No. 44269, from glacial drift
(probably originally from the Coldwater formation), Hillsdale or Kalamazoo
County, Mich. 44. Lateral view of latex cast of hinge line, X4.8; note the three
posterior lateral teeth subparallel to dorsal margin and the three oblique anterior
teeth and two prominent sockets. 45, 46. Lateral and dorsal views. 47. Oblique view
of anterior portion of specimen, X4.8; note muscle scar and mold of anterior denti-
tion.
48. Lateral view of latex cast of natural interior mold of left valve, UMMP, No.
44270, from glacial drift (probably originally from Coldwater formation), Hills-
dale or Kalamazoo County, Mich., X4.8. Note three posterior lateral teeth and
three oblique anterior teeth with two prominent associated sockets,
83
105
98
99
PALAEONTOGRAPHICA AMERICANA, VOL. V Page 15
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-5.
MISsSISSIPPIAN DIMYARIAN PELECYPODS: DRISCOLL
EXPLANATION OF PLATE 16
All figures X1.2, except as noted.
Parallelodon (Cosmetodon) marshallensis (Winchell) .......:cscccccsscsccssscesescscesescessecececeeseee
1-3. Right valve, holotype, UMMP, No. 26877, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. Dorsal, lateral, and anterior views.
4. Lateral view of right valve, OSU, No. 19671, from the Allorisma zone, Allensville
member, Logan formation, at Rushville, O. This specimen was intended by Hyde
to be holotype of Parallelodon depressus.
5. Lateral view of right valve distorted by compression, OSU, No. 19671, from the
Allorisma zone, Allensville member, Logan formation, at Rushville, O. This specimen
was intended by Hyde to be a paratype of Parallelodon depressus.
Schizodus rostratus (Winchell) os a
6-10. Natural internal mold of right valve, lectotype, MP, No. 26884, from
the Marshall sandstone at Battle Creek, Calhoun Co., Michigan. 6, 7. Anterior and
lateral views. 8. Latex cast of dentition, X2.4; note strongly developed cardinal
tooth (3a) and large socket for reception of cardinal (2). 9. Dorsal view. 10. Oblique
view of anterior adductor scar and accessory scar; note radial and concentric
sculpture of adductor and that shallow groove extends across adductor scar to join
pallial line. Note that accessory scar is above adductor near margin.
11-14. Natural internal mold of left valve, paralectotype, UMMP, No. 44281, from
the Marshall sandstone at Battle Creek, Calhoun Co., Mich. 11-13. Lateral, anterior,
and dorsal views. 14. Latex cast of dentition, X2.4; note subbifid cardinal tooth (2).
15-18. Natural internal mold of right valve, hypotype, UMMP, No. 44282, from the
Marshall sandstone at Holland, Ottawa Co., Mich. 15. Oblique view of anterior
adductor scar and accessory scar, X2.4; note radial and concentric ornamentation of
adductor, the groove extending across adductor scar to pallial line, and accessory
scar above and to the right of adductor scar. 16, 17. Anterior and lateral views.
18. Latex cast of dentition, X2.4.
19. Cast of dentition of left valve, hypotype, UMMP, No. 44283, from the Marshall
sandstone at Holland, Ottawa Co., Mich., X2.4. The natural mold of this artificial
cast is partially preserved, that portion showing the dentition apparently having
been lost. Note that all three cardinal teeth and two sockets (4a-2-4b) are well pre-
served and escutcheon is visible.
20. Oblique view of posterior adductor scar and accessory scar on natural internal
mold of left valve, hypotype, UMMP, No. 44283, from the Marshall sandstone at
Holland, Ottawa Co., Mich., X2.4. Note the concentric and radial striations of ad-
ductor scar and the accessory scar just above and to the left of the adductor. A cast
of this specimen is shown in fig. 19.
21. Ventral view of hinge area of latex cast, hypotype, UMMP, No. 35554, from
Holland, Ottawa Co., Mich., X2.4. Note the articulation of the valves. Anterior is up
in the figure and the right valve is shown on the left. The strongest cardinal teeth of
each valve (3a and 2) are clearly shown.
124
Figure
1-13.
PALAEONTOGRAPHICA AMERICANA (V, 35)
EXPLANATION OF PLATE 17
All figures X1.2, except as noted.
Schizodus® vstrmtitise NWaAnCHelll))i 0 recsssseeececoncsonccaescsercterneoaeeee reece ecco eeaee serene reine ocerneccesaceeeste cress
1-4. Natural internal mold of right valve, lectotype, UMMP, No. 44285, from the
Marshall sandstone at Marshall, Calhoun Co., Mich. 1, 2. Dorsal and lateral views.
Oblique view of anterior adductor muscle scar and of natural mold of hinge
structure, X2.4. 4. Latex cast of hinge structure, X2.4.
5-8. Natural internal mold of right valve, paralectotype, UMMP, No. 44286, from
the Marshall sandstone at Marshall, Calhoun Co., Mich. 5. Lateral view. 6. Oblique
view of anterior adductor scar, X2.4; note ridge extending across scar and short
groove in umbonal region of mold. 7. Dorsal view. 8. Oblique view of posterior ad-
ductor scar, X2.4; note concentric sculpture of muscle scar and ridges and grooves
adjacent and anterior to scar.
9, 10. Natural internal mold of right valve, paralectotype, UMMP, No. 44287, from
the Marshall sandstone at Marshall, Calhoun Co., Mich. 9. Latex cast of hinge
line of natural internal mold, X2.4. 10. Lateral view.
11-13. Left valve, partially an internal mold, hypotype, UMMP, No. 44288, from the
Marshall sandstone at Battle Creek, Calhoun Co., Mich. 11. Latex cast of hinge
structure, X2.4. 12. Lateral view. 13. Surface sculpture near ventral margin of
valve, X4.8.
Schigodus sectoralis: (Winchielll))) Resse ssccecsescecesctsocecectentece esvecesreseesreenneeaaveantesteeesessesererseesenscinte
14-16. Right valve, holotype, UMMP, No. 26876, from the Marshall sandstone at
Marshall, Calhoun Co., Mich. Note that specimen is slightly distorted. Anterior,
lateral, and dorsal views.
17, 18. Natural internal mold of right valve, hypotype, UMMP, No. 44291, from
the Marshall sandstone at Battle Creek, Calhoun Co., Mich. Dorsal and lateral
views.
19, 20. Left valve, hypotype, UMMP, No. 44290, from the Marshall sandstone at
Battle Creek, Calhoun Co., Mich. 19. Latex cast of hinge line of natural internal
mold, X4.8. 20. Lateral view of natural internal mold.
21-23. Natural internal mold of left valve, hypotype, UMMP, No. 44292, from the
Marshall sandstone at Battle Creek, Calhoun Co., Mich. 21. Oblique view of poster-
odorsal portion of specimen showing posterior adductor scar and truncate pallial
line, X2.4. 22. Lateral view. 23. Oblique view of anterior portion of specimen show-
ing anterior adductor scar, X2.4.
24-26. Natural internal mold, hypotype, UMMP, No. 35553, from the Marshall sand-
stone at Holland, Ottawa Co., Mich. 24, 25. Lateral and anterior views. 26. Ventral
view of latex cast of hinge line illustrating articulation of valves; the main cardinal
of the right valve (3a) lies anterior to the principal cardinal of the left valve (2) ;
anterior is toward the top of the plate.
103
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Page 18
Figure
LoS.
6-20.
MISsSISSIPPIAN DIMYARIAN PELECYPODS: DrIscoL.
EXPLANATION OF PLATE 18
All figures X1.2, except as noted.
WaniZocdusm trian gaLlanism (Eergick) meee tener eee ee
1. Lateral view of left valve, hypotype, UMMP, No. 44298, from the Marshall
sandstone at Battle Creek, Calhoun Co., Mich.
2-4. Right valve, hypotype, UMMP, No. 2228 (Mich. Geol. Survey, No. 19257),
from the upper Coldwater formation at Pte. aux Barques lighthouse, Huron Co.,
Mich. This specimen was illustrated by Lane and Cooper (1900, p. 264, pl. 11, fig. 7).
Dorsal, lateral, and anterior views.
5. Lateral view of right valve, hypotype, UMMP, No. 2227 (Mich. Geol. Survey, No.
19256), from the upper Coldwater formation at Pte. aux Barques lighthouse, Huron
Co., Mich. This specimen was illustrated by Lane and Cooper (1900, p. 264, pl.
11, fig. 8).
WSichiz OCU ime NUCH SIN BoB TL OU peers ce ete Rena RT Tiree die SR OR,
6-10. Natural internal mold, holotype, UMMP, No. 44299, from the Marshall sand-
stone at Battle Creek, Calhoun Co., Mich. 6. Oblique view of anterior portion of
mold, X2.4; note pronounced anterior adductor scar on which a small radial ridge
is present; also note distinct groove adjacent to posterior side of adductor. 7. Lateral
view. 8. Oblique view of posterodorsal portion of mold, X2.4; note distinct posterior
adductor scar which is divisible into two parts, the anterior being more pronounced
than the posterior. 9. Oblique view of umbonal region, X4.8; note structure extending
from umbonal part of internal mold through shell which is thought to be due to boring
marine organism. 10. Oblique view of anterior portion of mold, X4.8; note pallial line
connecting with ridge on anterior adductor scar and nodes on surface of mold.
11-13. Right valve, paratype, UMMP, No. 44300, from the Marshall sandstone at
Battle Creek, Calhoun Co., Mich. Lateral, dorsal, and anterior views.
14-17. Right valve, paratype, UMMP, No. 44301, from the Marshall sandstone at
Mosherville, Hillsdale Co., Mich. 14. Lateral view of hinge line, X2.4. Note the
prominent inclined cardinal tooth bounded by two sockets. 15. Anterior view. 16.
Dorsal view; note the two grooves on the postumbonal slope. 17. Lateral view.
18-20. Right valve, paratype, UMMP, No. 44302, from the Marshall sandstone at
Mosherville, Hillsdale Co., Mich. 18. Shell ornamentation on anterior portion of
valve, X4.8. 19, 20. Lateral and dorsal views.
104
INDEX
NUMBER 35
Note: Light face figures refer to the page numbers. Bold face figures refer
to the plate numbers.
A
abbreviatus, Solen 89
Acila 69, 70, 74
Adams Twp.,
Michigan 107
aeolus, Sphenotus 84-87,
105
Alan’s quarry,
Hillsdale County,
Michigan 73, 94,
98, 107
alata, Prothyris 81-83
alfredensis, Solen 89
Allensville
member 74, 87,
100, 105, 106, 108
Allorisma 91, 93-
96, 99, 105
allorismaformis,
Palaeoneilo 71
ambiguus, Solen 89
amii, Palaeosolen 90
angusta, Edmondia? 84
angustatus,
Sanguinolites 83
annandalei, Solen 89
antigonishensis,
Palaeosolen 90
arcaeformis,
Sanguinolites 85
astartaeformis,
Ctenodonta 68
B
barrisi, Leda 71
Battle Creek,
Michigan MO nls
76, 78, 80, 83-85,
87, 90, 91, 99,
101-105, 107
belgicus,
Palaeosolen 89
bellistriata, Leda 79, 80
Nuculana 80
Polideveia 80
bellistriata?, Leda 79, 80
bergica, Prothyris 83
Beuschausenia : 98
bisulcata,
Grammysia 90
Black Hand
member 83, 94, 98,
105, 106, 108
Brandywine Creek,
Summit County,
Ohio 94
brevis, Solen .... 89
Burlington, Iowa | 92, 94, 97
burlingtonensis,
Sanguinolites? 84
Byer member 74, 94,
105, 106
Byer, Ohio 94, 98
Cc
Calhoun County,
Michigan 70, 80, 83-
85, 87, 91, 99,
100, 102-105
Carboniferous
limestone 94-97,
106, 108
Cardinia 72
chapmani,
Palaeosolen 89
cingulata, Nucula 91
Clidophorus 88
Coldwater
formation 80, 94-
96, 98, 99,
104-106, 108
complanata,
Cardinia 72
concentrica,
Cardinia Yee
Palaeoneilo PD ler}
105-108
?Palaeoneilo 71, 105
Sanguinolites WES
concentrica var.,
Palaeoneilo 71
concentricus,
Sanguinolites 71
constricta,
Leptodomus 96
Nuculites 70
constrictus,
Leptodomus 96, 97
contorta, Prothyris 83
corbuliformis?,
Nucula 74
corneus, Solen 89
Cosmetodon 73, 74,
83, 98-100,
105-107
costatus,
Palaeosolen 90
costellatus,
Sanguinolites 92
Ctenodonta 67, 68
curtus, Sphenotus 105
cuyahoga,
Allorisma 91, 96
Grammysia 91, 94-96
Cuyahoga
formation 94-96,
98, 105, 106, 108
Cypricardella 67, 105,
106
D
densmamillata,
Leda 79
depressus,
Parallelodon 99, 100
Derbyshire 92-97,
108
divaricata, Acila 69, 70
dorsocurva,
Solenomorpha LES “Ore
88, 89, 106, 107
E
Edmondia .... : 83
ehlersi, Schizodus .. 18 67,
104-107
elegans, Prothyris 81-83
126
elegantula,
Palaeoneilo 71
elliptica,
Palaeoneilo 72
ellipticus,
Palaeoneilo (AGP
ellipticus var.
allorismaformis,
Palaeoneilo ; 71
var. elegantula,
Palaeoneilo 71
var. plicatella,
Palaeoneilo 71
England . 94, 95,
97, 106, 108
Ennucula .. 69,74
Eureka District,
Nevada 94, 95,
97
exuta, Prothyris 81-83
F
famelica,
Grammysia 91
Fayette quarry,
Hillsdale County,
Michigan 94, 98,
107
frontisocurvus,
Palaeosolen 13 67,
90, 91, 106, 107
G
Germain’s quarry,
Hillsdale County,
Michigan 73, 107
girtyi, Nuculopsis 70, 74
gouldi, Solen ; 89
Grammysia 67, 72,
90-92, 94-98, 106-108
Grammysoidea 91
grandis, Solen 89
Granville, Ohio 84
Grass Lake,
Jackson County,
Michigan 2, 83,
87
Grindstone quarries,
Pte. aux Barques,
Michigan 87, 107
H
Hamiltonensis,
Allorisma 93
hamiltonensis,
Grammysia : 91
hamiltoniae,
Parallelodon 99
hammer,
Palaeonucula 74
hannibalensis,
Allorisma 93-96
?Allorisma 91
Grammysia 91-97
Grammysia? 94, 98
?Grammysia? 91
Sanguinolites 91, 97,
98
Sedgwickia 91
Hannibalis,
Grammysia 93
herricki, Grammysia 91
Sanguinolites 84, 105-
107
Sanguinolites? Ue 8}
84, 107
Hillsdale, Michigan 73, 86,
87, 107
Hillsdale County,
Michigan 80, 81,
83-85, 87, 94,
98, 105, 107
Holland, Michigan 83, 84,
102, 104, 107
houghtoni, Nucula 75-77
Nuculopsis 8 69, 75,
76, 78, 105-107
hubbardi, 5
Ctenodonta 70
Nucula 69-71
Palaeoneilo {fal
Huntington County,
Pennsylvania 73
Huron County,
Michigan 104
hydei, Grammysia 14 67,
91-98, 106
|
inflata, Yoldia 69
Iowa 92, 94-
97, 106, 108
iowensis, Nucula 76-78
Nuculopsis 7! tte ths
irvinensis,
Parallelodon 99
J
Jackson County,
Michigan 70, 71,
82, 83, 87, 103
jessieae, Prothyris 83
Jonesville,
Michigan 72, 107
K
Kalamazoo,
Michigan 76, 78,
80
karagandensis,
Leda 79
Kent County,
Michigan Ona:
107
keyserlingi,
Beushausenia 98
Kinderhook group 92, 94-
97, 106, 108
krausenstenii,
Solen 89
L
lanceolata,
Prothyris 81-83
Leda 79-81
legumens, Solen 89
Leptodomus 91
Licking County,
Ohio 73, 83,
86
INDEX
limatula (?),
Yoldia 69
lirata, Nucula 74, 78
Little York, Ohio 94
Logan formation 74, 87,
94, 100, 105, 108
logani, Ctenodonta 67, 68
Louisiana limestone 94-96
Louisiana, Missouri 94
Lower
Carboniferous 94, 95,
97, 106, 108
Lower Coal
Measures 96
Lower Marshall
sandstone 100
Lowick, England 94, 97
M
Macrodon 98
Marklesburg,
Pennsylvania 73
Marshall, Michigan 78, 80,
83, 85, 87-90,
99, 100-104, 107
marshallensis,
Cosmetodon 16 73, 74,
99, 100, 105-107
Palaeoneilo? 73
Palaeoneilo (?) 73
Parallelodon 16 73, 74
99, 100, 105-107
Sanguinolites 73, 74,
99, 100
?Sanguinolites 73
Medina, Ohio 94, 98
Medina County,
Ohio 85
meeki, Prothyris 83
Microdon 105
minor,
Solenomorpha 87
minutus,
Palaeosolen 89
Missouri 74, 94-
96, 106, 108
Modiomorpha 83
montereyensis,
Yoldia 69
Moscow, Michigan 71, 80,
81, 83-85, 87, 88, 107
Mosherville,
Michigan 73, 80,
105, 107
N
naiadiformis,
?Sanguinolites 85-87
Napoleon,
Michigan 70, 71,
87, 88, 107
Napoleon Railroad
Cut, Jackson
County,
Michigan 103, 107
Napoleon sandstone 108
nasuta, Tellinomya 67, 68
Nebraska 88
Nebraska City,
Nebraska 88
Nevada 92, 94,
95, 97, 106, 108
127
Newark, Ohio 73, 74,
79, 85, 87,
a 100, 105
nitida, Solenopsis 87
Northumberland,
England 94-97, 108
Northview, Missouri 94
Northview
siltstone 74, 94-96,
106, 108
nucleus, Nucula 69
Nucula 68-71,
74-78, 91
nuculaeformis,
Leda 79, 80
Nuculana 79, 80
Nuculites 70, 71
Nuculoma 74
Nuculopsis 67, 70,
: 74, 77, 78
Nuculopsis sp. Uf "As
te)
obliqua, Ennucula 69, 74
obliquus,
Sanguinolites 85
Sanguinolites? 85
Sphenotus 1282)
84-87, 105-107
oblongus,
Sanguinolites 86
obscurus, Schizodus 100
occidentalis,
Palaeosolen 89, 90
Ohio 79, 81
83-87, 90, 94-96,
98-101, 104-106, 108
ohioensis, Leda 79
omaliana,
Grammysia 14 91-98,
106-108
Pholadomya 91
omalianus,
Sanguinolites 91-97
Orthonota 81
Osagean 108
Osseo, Michigan 107
Ottawa County,
Michigan 83, 84,
102, 104
ovatus,
Cosmetodon 15 98, 99,
105-107
Parallelodon 15 98, 99,
105-107
P
Palaeaneilo 70, 100
Palaeoneilo 67, 68,
70-73, 105-108
Palaeonucula 74
Palaeosolen 67, 88-
91, 105-107
pandoraeformis,
Leda 79, 81
Polideveia 10 79, 80,
105-107
pandoriformis,
Leda 79, 80
parallela, Prothyris 81, 82
Parallelodon ROwos
74, 83, 98-100, 105-107
Parallelodon sp. 15 99
patula, Siliqua 89
Pennsylvania 96, 106,
108
pentlandicus,
Schizodus 100
Pholadomya 91
planulata,
Prothyris 81-83
plena, Grammysia 91, 92,
94-97
Grammysia cf. 91, 98
plicatella,
Palaeoneilo 71
Pocono group 106
Pocono sandstone 108
Polidevcia 10) 67;
78-80, 105-107
prolata, Nucula Ow real
Prothyris 67, 81-
83, 105-107
Pte. aux Barques,
Michigan 78, 104
Q
quadrangularis,
Palaeosolen 13. 88-
91, 105-107
Solen 89
R
randalli, Nucula 74, 76
rectangularis,
Cypricardella 105
rectidorsalis,
Orthonota 81, 82
Prothyris 11 ~81-
83, 105-107
rhomboides,
Grammysia 91
Riddlesburg,
Pennsylvania 73
rostrata,
Grammysia 94-96,
98
Sanguinolaria 101
rostratus,
Schizodus 16 101-
103, 106, 107
rugosus, Macrodon 98
Rushville, Ohio 74, 87,
100, 105
S
Sanguinolaria 101-103
Sanguinolites 67, 71,
73, 74, 83-88,
91, 100, 105-107
sapotilla, Yoldia 69
Saxon,
Pennsylvania 73
scalprata,
Prothyris 83
scalpriformis,
Solen 87, 88
INDEX
Solenomorpra Seis
88, 106, 107
scalpriformis var.,
Solen 88
Schizodus 67, 78,
100-107
Sciotoville, Ohio 74, 94
Secret-canon road,
Eureka District,
Nevada 94, 95,
97
sectoralis,
Nucula 76-78
Nuculopsis 7,0 d=
77, 106, 107
Sanguinolaria 103
Schizodus 17 103,
104, 106, 107
securis,
Cypricardella? 15 105,
106
Cyprocardia? 105
Sanguinolites 105
Sedgwickia 83, 91
Sharpsville
sandstone 94-96
Siliqua 89
siliquoideus,
Palaeosolen 88, 89
siliquus, Solen 89
similis, Leda 80
Nuculana 80
Sanguinolaria 101-103
Schizodus? 17 102;
103, 106, 107
Solen 81, 87-89
solenoides,
Clidophorus 87
Solenopsis 88
Solenomorpha 88
Solenomorpha 67, 81.
87-89, 106, 107
Solenopsis 81, 87,
88
spatulata, Leda 80
Nuculana 80
Sphenotus 67, 83-
87, 105-107
stella,
Ctenodonta 7 68, 71,
75, 106, 107
Nucula 68
Nuculopsis 68
subarcuata,
Grammysia 97
subelliptica,
Cypricardella 105
sulcatina,
Nuculites Ose
Palaeoneilo 9 70-72,
106, 107
sulcatus,
Parallelodon 99, 100
Summit County,
Ohio 94
Vu.
Tellimya 68
Tellinomya 67, 68
Thomas Doyle Farm,
Vinton County,
Ohio 94
128
Thorpe Cloud,
England 92-94, 97
Top Orchard quarry,
England 97
triangularis,
?Macrodon ?? 104
Schizodus 18 104-
: 107
tricostatus,
Sanguinolites 86
Sphenotus 86
trigonalis,
Schizodus 103
truncata,
Palaeoneilo OP a73;
74, 99, 100, 106
U
undulata,
Orthonota 81
unioniformis,
Sanguinolites 11 83-85,
105-107
?Sanguinolites 83
Vv
vaginus, Solen 89
variabilis,
Sanguinolites 91-97
ventricosa,
Nucula 69, 74
Nuculopsis 70, 74
ventricosta,
Grammysia 91
Vinton County,
Ohio 83, 94,
; 98
Vinton member 74, 106
Visean, Zone D 93, 94-
97, 106
Vogelmeier quarry,
Newark, Ohio 100
Ww
Waverly group 78, 81,
83, 85-87, 90,
99, 101, 105, 108
Waverly quarry,
Ottawa County,
Michigan ffl
Waverly sandstone 94-96, 98
websterensis,
Sanguinolites 86
wheeleri, Schizodus 102
Wilkes-Barre,
Pennsylvania 96
Wilkingia 92, 96
Winchell, Alexander 67
winchelli,
Allorisma 105
Wilkingia 96
ay,
Yellow sandstone 94, 97
Yoldia 69, 74
ENERCNOWV Neu INOS39155=160) 04:12 spp syn SOM DIS.) ecestccssencsessecsdosecosbasesevdn
Globotruncana in Colombia, Eocene fish, Canadian-Chaz-
yan fossils, foraminiferal studies.
SNORT (NOs: 1 61-164) 5) e486 upp iyp SZiDiSs)lensrasecsreseresesencessveserececcoeeversnesccserce
Antillean Cretaceous Rudists, Canal Zone Foraminifera,
Stromatoporoidea
MEXSKGVITTS (Noss 165-1176) io 44-7. pps 53) Pl Be: cersencoce cass easter cs eee eeeneece cence sce
Venezuela geology, Oligocene Lepidocyclina, Miocene ostra-
cods, and Mississippian of Kentucky, turritellid from
Venezuela, larger forams, new mollusks, geology of Car-
riacou, Pennsylvanian plants.
XOKCKIEK, (Nos. 177-183))5, 448) pps, 36 ples ees cece weeeracceeene
Panama Caribbean mollusks, Venezuelan Tertiary forma-
tions and forams, Trinidad Cretaceous forams, Ameri-
can-European species, Puerto Rico forams.
ibe (ON, TDs CEYS TD» Tb comersecete atime
Type and Figured Specimens P.R.1.
EXT 1(INOs:) 1 85-11.92))ene 3 Sls pps es Simp Iso eeecatecesses meno cpcecceeerceenea ees
Australian Carpoid Echinoderms, Yap forams, Shell Bluff,
Ga. forams. Newcomb mollusks, Wisconsin mollusk
faunas, Camerina, Va. forams, Corry Sandstone.
SIG (Oni TOR 5 0B Totes GE) BIBS erecmaeocptacenastenset rospsp rear oneoeoeeceormeoos
Venezuela Cenozoic gastropods.
SNOPIITS (Noss (194-198))) 427 pps SOM PSE ccscsceccessecsccessccsreccevarcyscseepseenevecseten
Ordovician stromatoporoids, Indo-Pacific camerinids, Mis-
sissippian forams, Cuban rudists.
DTN. (INog- 91992203) 3.65: Diy OS: PIS i ceeeaeensaenccestcecevcveeecneasoceesxceoe
Puerto Rican, Antarctic, New Zealand forams, Lepidocy-
clina, Eumalacostraca.
ERAAW mn (UNOS 204) stn OAD Jos PDS stnccccesenvossconececeansesterorasrvsayrersstevss essstusests
Venezuela Cenozoic pelecypods
DAVIE (Noss 205-201) 5 > 4190 pp., 70) pls), cana vcce eas ccenseeoscsseserccceesevecacens
Large Foraminifera, Texas Cretaceous crustacean, Ant-
arctic Devonian terebratuloid, Osgood and Paleocene
Foraminifera, Recent molluscan types.
RAWAM CIN OHS 2LE-21 9) e574 DPS Si DIS dercssnctncecuecatssencorpsstccarsysstancaccxenesueseoses
Eocene and Devonian Foraminifera, Venezuelan fossil
scaphopods and polychaetes, Alaskan Jurassic ammonites,
Neogene mollusks.
RO VAM INO n 218) ie) 4640 peg Si DIS. cecsvescensesnsovsscececesssncencararssnoseveersnssacnosoveseres
Catalogue of the Paleocene and Eocene Mollusca of the
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Jackson Eocene mollusks.
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sylvanian crinoids, Cypraeidae, Cretaceous, Miocene and
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(Continued inside back cover)
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1966
Paleontological Research Institution
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ACKNOWLEDGMENTS
The present work was carried out in partial fulfill-
ment of the requirements for the degree of Doctor of
Philosophy at the University of Cincinnati. ‘The author
extends his sincere thanks to the members of the Depart-
ments of Biological Sciences and Geology at the University
for generously giving of their time and knowledge during
the preparation of the manuscript. Especial thanks is ex-
tended to Dr. K. E.
manuscript was prepared. He was a source of help and en-
Caster, under whose direction the
couragement, and his invaluable library made many rare
works readily available to me. I am indebted to Dr. Norman
D. Newell for reviewing the manuscript and offering many
helpful suggestions. To my wife continuing thanks for
proofreading and typing the greater bulk of the manu-
script.
I would like to thank the following individuals for
placing museum specimens and type materials at my dis-
posal: Dr. R. L. Batten and Dr. N. D. Newell, American
Museum of Natural History; Dr. R. E. Sloan, University of
K. Pope and Dr. R. Reinhart,
Minnesota; J. Miami
University, Oxford, Ohio; Dr. D. W. Fisher, C. F. Kil-
foyle, and Dr. L. V. Rickard, New York State Museum;
Dr. E. C. Stumm, University of Michigan; Dr. R. S. Board-
man, Dr. G. A. Cooper, and Dr. E. G. Kauffman, United
States H. Nitecki, Walker Mu-
seum, University of Chicago; Dr. A. L. McAlester, Peabody
National Museum; M.
Museum, Yale University; and Dr. E. S. Richardson, Jr.,
Chicago Natural History Museum.
In appreciation for helpful correspondence I would
like to thank: Dr. M. J. Copeland, Geological Survey of
Canada; Dr. G. M. Kay, Columbia University; Dr. L. S.
Kent, Ilinois State Geological Survey; Dr. T. Kobayashi,
Imperial University of ‘Tokyo; Dr. G. Regnell, Lund Uni-
versity, Lund, Sweden; Dr. B. Ruzicka, Mining University,
Ostrava, Czechoslovakia; and Dr. H. Scott, University of
Illinois.
The cost of the engraving of the illustrations has been
met by a grant from the Graduate School of the University
of Cincinnati.
CONTENTS
Acknowledgments
VAIDStraGey secs sss-=
Introduction
Shell morphology
I. External
II. Internal features
Systematic paleozoology
Phylum Mollusca (Pelecypoda)
Generic descriptions
Generic differentia
Allonychia
Species descriptions ..........:.sseeees
Ambonychiopsis
North American species listing and remarks ..........
Amphicoela
Species listing
Anomalodonta
Species description
Anoptera
Species descriptions
Ambonychia
New materials and species descriptions .....
Byssopteria .....
Species listing
Cleionychia
Species listing
Congeriomorpha
Ectenoptera
Eridonychia
Goss eletiaupeccc.c tect esce
North American species
Lophonychia
Maryonychia
Species description ..
Megaptera
M ytilarca
North American species .
Silurian species
Devonian species
Opistholoba
Opisthoptera
Species descriptions
Palaeocardia
Plethomytilus
Psilonychia
Streptomytilus
Ambonychiid phylogeny. ....
Bibliography
Appendix
Plates
NORTH AMERICAN AMBONYCHIIDAE
(PELECYPODA )
JOHN PojeTa, JR.
University of Cincinnati!
ABSTRACT
The purpose of the present work is to give a detailed account of
the morphology and taxonomy of the poorly known Early Paleozoic
pelecypod family Ambonychiidae. An extensive generic restudy of the
North American forms has been carried out, and the phylogenetic re-
lationships of the family are considered.
Ambonychiids are equivalved, inequilateral, byssate pelecypods
which show morphological similarities to the Paleozoic families My-
alinidae, Pterineidae, and Cyrtodontidae. Sixteen North American gen-
era, ranging in age from the Middle Ordovician to the Late Devonian,
are herein regarded as belonging to the Ambonychiidae. The generic
names Byssonychia Ulrich, Ectenoptera Ulrich, Eridonychia Ulrich,
Plethomytilus Hall, Opistholoba Ulrich in Hussey, and Streptomytilus
Kindle and Breger are not recognized as valid. One new genus
Maryonychia is proposed.
INTRODUCTION
The present investigation is concerned with the com-
parative morphology, taxonomy, and phylogeny of the Early
Paleozoic pelecypod family Ambonychiidae.
A great deal of the present knowledge of North Ameri-
can Early Paleozoic pelecypod faunas rests upon a series of
pioneer monographs prepared during the middle and late
nineteenth century. These monumental monographs _ pro-
vided the first insight into the older pelecypod faunas, but
with the passage of time they have become less and less
satisfactory. Authors of the last century were largely con-
cerned with descriptions of species; generic and higher taxa
concepts were often only vaguely defined, and details of
morphology often omitted. In addition, workers of this
period necessarily published only drawn figures of their ma-
terials. It was a custom of the time to include interpretive
conclusions on these drawings, and often this was done
without adequate notation that the specimens showed
various features in an equivocal manner. As a result, highly
erroneous ideas as to taxonomic placement and morpho-
logical structure are often obtained from only a literature
study, and restudying and refiguring of original materials
are necessary. Included herein are photographs of almost
all of the type materials of the type species of the various
genera considered. In addition, type materials of numerous
other species are refigured.
Because the uncertainty of generic concepts is a
pressing problem in the study of Early Paleozoic pelecypods
the taxonomic portion of the present work is largely con-
cerned with an extensive generic revision of North Ameri-
can ambonychiids. The problem of inadequate generic
1. Present address: United States Geological Survey, Paleontology
and Stratigraphy Branch, Room E-315, United States National
Museum, Washington, D.C. 20242.
concepts hinders the study of other aspects of the paleo-
zoology of Early Paleozoic pelecypods. Specific revision is
limited to those species occurring in the Upper Ordovician
rocks of the Tristate Area of Ohio, Indiana, and Kentucky.
However, for all of the included genera, species listings
are given following the discussion of each genus.
For various reasons the following generic names are
not recognized herein: Byssonychia Ulrich, Ectenoptera Ul-
rich, Eridonychia Ulrich, Plethomytilus Hall, Opistholoba
Ulrich in Hussey, and Streptomytilus Kindle and Breger.
One new genus Maryonychia is erected. With these emenda-
tions the family is considered to contain 16 North American
genera.
As a taxonomic unit the family Ambonychiidae was
proposed by Miller in 1877. However, the various genera
assigned to it since that date have never been studied in
toto, and as is true with many of the intermediate taxa
the family has grown up in a rather haphazard way. The
addition of genera to the family was such that the concept
implied by the family name has become more and more
hazy with the passage of time. The familial concept is
herein redefined so as to include the nominate genus and
such additional genera as form a compact morphological
and probable phylogenetic unit.
The morphological portion of this study is concerned
with structural details and the known limits of variability
of these features in the Ambonychiidae. In the concluding
portion of this paper the possible phylogenetic relation-
ships of the family are discussed.
Ulrvich’s important Ordovician pelecypod paper which
appeared in volume 7, part 2, of the Reports of the Ohio
Geological Survey is apparently misdated. On the title
page and in many North American bibliographies the date
given for volume 7, part 2, is 1893. However, the most
probable date of publication was 1895, and references to
paleontological works appearing in volume 7 are herein
designated 1893 (1895).
Miller (1897, p. 719) wrote: “The Report of the Geo-
logical Survey of Ohio, Vol. VII, was published in Febru-
ary, 1895. The title page is dated 1893. The map which faces
the title-page bears the date of 1894, . . . The article on
‘Recent Changes in Nomenclature,’ by W. A. Kellerman, on
page 80a, is dated ‘Ohio State University, January, 1895.’ ”
Orton (1906, p. 17) gave the date of part 2 of volume 7
as 1894. Hyde (1953) gave the date as 1893 on pages 300
and 315, and 1895 on pages 228, 254, and 249; Derby and
156 PALAEONTOGRAPHICA AMERICANA (V, 36)
Prosser (1906, pp. 31-32) gave the date of volume 7 as
“1893-4” and noted that 1893 belongs to vol. 7, part 1
only; and Weller (1898, p. 37) gave the date as 1895.
The date 1895 is accepted herein because of Miller's
statement that this is the correct date, and because page 80a
in volume 7 is dated 1895.
The need for large numbers of type specimens has
required the accumulation of materials from numerous
museums, the names of which are subsequently abbreviated
as follows: 1) American Museum of Natural History —
A.M.; 2) Minnesota Geological Survey, University of Min-
nesota— M.G.S.; 3) Miami University, Oxford, Ohio —
M.U.; 4) New York State Museum—N.Y.S.M.; 5) Paleon-
tological Research Institution, Ithaca, N.Y.—P.R.1.; 6)
University of Cincinnati Museum — U.C.M.; 7) University
of Michigan, Museum of Paleontology —U.M.; 8) United
States National Museum — U.S.N.M.; 9) Walker Museum,
University of Chicago — W.M. (Walker Museum specimens
are now at the Chicago Natural History Museum. They con-
tinue under their old catalog numbers.) ; 10) Peabody
Museum of Natural History, Yale University — Y.P.M.
SHELL MORPHOLOGY
1. EXTERNAL FEATURES (Text-figures I and II)
A. TOTAL EXTERIOR ASPECT
Ambonychiids have three, usually readily recognizable
external features in common; all members of the family
are equivalyed, markedly inequilateral, and have a_byssal
sinus.
The inequilateral shell is characterized by the trunca-
tion of the anterior end, with a severe reduction or total
loss of the portion anterior to the beaks. Accompanying
the loss of the anterior end there is a reduction or total loss
of the attendant musculature. Two broad types of anterior
faces can be distinguished within the family. The first type
is characterized by the presence of a projecting antero-
dorsal portion of the shell (Text-figure I-8), while the
second type lacks the anterodorsal salient (Text-figure I-6) .
The anterodorsal salient, herein arbitrarily referred to
as the anterior lobe, varies in its prominence in different
genera and differs somewhat in size and shape in shelled
and nonshelled specimens of the same form. Among North
American ambonychiids the anterior lobe is known in four
genera: Ambonychiopsis Isberg (Pl. 22, fig. 14), Allonychia
Ulrich (Pl. 19, fig. 1), Congertomorpha Stoyanow, and
Gosseletia Barrios (Pl. 35, fig. 8).
In the numerous genera which lack an anterior lobe
there is usually no projection of the anterior face of the
shell forward of the beaks (e.g., Lophonychia Pohl, Pl. 36,
fig. 5). However, in a minority of forms an anteroventral
salient of the shell projects forward of the beaks. This trait
is best developed in the Silurian genus Amphicoelia Hall
(Pl. 25, fig. 4) where it is a constant generic feature. The
anteroventral salient also occurs sporadically in species be-
longing to other genera such as Mytilarca oviformis (Con-
rad) (PI. 41, fig. 4) and
(Pojeta, 1962, pl. 31, fig. 5).
According to Newell (1942, p. 20): “Primitive Mytil-
acea .. . are characterized by an anterodorsal salient, called
Ambonychia casteri (Pojeta)
the anterior lobe, in front of and below the beaks. Reduc-
tion of this lobe, with a tendency thereby for the beaks to
become progressively more terminal, is distinctly a mark of
specialization .. . "’ Among ambonychiids, those forms with
an anterior lobe are herein regarded as the morphologically
more primitive and less specialized members of the family.
The loss of the anterior lobe is a specialization which re-
occurs throughout the stratigraphic range of the family.
Forms with an anterior lobe may represent a phylogenetic
entity, because, following Dollo’s Law, they could only have
arisen from forms already possessing such a lobe. Nonlobate
forms, on the other hand, could have arisen either from
nonlobate forms or from lobate species, and thus probably
represent a morphological grade of organization which was
developed repeatedly in the evolution of the family rather
than a phylogenetic unit.
In any event, whether the anterior lobe is present or
not, the anterior end of the shell is always highly reduced.
In those forms where the anterior lobe is present, the reduc-
tion has not progressed so far as in those lacking the lobe.
This extreme reduction of the anterior end is also charac-
teristic of the Myalinidae, a family of Late Paleozoic pelecy-
pods which appears to be closely related to the Ambony-
chiidae.
With the obsolescence of the anterior end, the an-
terior musculature was also reduced and as a consequence
all ambonychiids are either heteromyarian or monomyarian.
Complete reduction of the anterior lobe does not neces-
sarily imply the total loss of the anterior adductor muscle.
In the Recent genus Mytilus Linné the anterior end of the
shell is completely reduced, however, a small anterior
adductor muscle is still present. This condition is not
presently known in ambonychiids, however, many species
and even genera are so poorly known that it may be found.
The complete absence of an anterior adductor muscle can
only be established when the anterior end of the pallial
line is known.
The shell of ambonychiids is always equivalved (Text-
NorTH AMERICAN AMBONYCHIIDAE: POJETA 137
6
Text-figure I:
This figure shows various external morphological features of the
Ambonychiidae. 1. Nonterminal beak: the beak is located posterior
to the anteriormost end of the dorsal margin. 2. Terminal beak: the
beak is located at the anteriormost end of the dorsal margin. 3. Various
linear dimensions of the shell: L-length, H-height, D-diagonal dimen-
sion. 4. T-thickness, measured on a shell lacking a discernible byssal
gape. 5. A-angle alpha, B-angle beta. 6. G-angle gamma, measured on
a shell lacking an anterior lobe. 7. T-thickness, measured on a shell
having a prominent byssal gape. 8. G-angle gamma, measured on a
shell having an anterior lobe.
138 PALAEONTOGRAPHICA AMERICANA (V, 36)
figure I-4) , that is, the two valves are mirror images of each
other, and thus exhibit bilateral symmetry (PI. 27, fig. 3).
This equivalved nature strongly suggests that there was no
genetic predisposition to lie habitually on one valve or the
other, but that the anterior face of the shell was in apposi-
tion with the substrate after the fashion of Mytilus Linné
and Modiolus Lamarck. On well-preserved specimens the
biconvex equivalved nature of the shell is readily seen. In
weathered or distorted materials the valves may differ in
convexity, but the similarity of the prosopon of the two
valves bears out the lack of habitual lying on one side.
Among the Paleozoic families which show morphologi-
cal similarities to the Ambonychiidae, only the Cyrtodonti-
dae is equivalved; both the Myalinidae and the Pterineidae
are inequivalved.
Ambonychiids possess a more or less well-developed
byssal sinus — that is, the indentation seen in lateral view
at the point where the byssal fibers leave the shell (PI. 28,
fig. 10). This feature is seen in the anterodorsal part of the
shell and varies in prominence in different species. It is
prominent in such forms as Anoptera misenert Ulrich (PI.
(PIP Al, figs),
and others; whereas, in Mytilarca foerstei Clarke and Ruede-
29, fig. 2), Mytilarca oviformis (Conrad)
mann (PI. 37, fig. 20) and other species it is hardly dis-
cernible.
In those forms which possess an anterior lobe it is
difficult to determine the position of the byssal sinus; pre-
sumably it is in the area immediately below the lobe. In
the species Allonychia jamesi (Meek) (PI. 19, fig. 7) there
is evidence to suggest that the apparent anterior lobe is
actually a protuberant byssal gape and that there is no
byssal sinus. However, the materials upon which this inter-
pretation is based are not well preserved, and final jude-
ment must be reserved until better specimens are found.
This problem will be discussed further under the genus
Allonychia Ulrich.
Size variability among ambonychiids is great, and in
almost all epochs large and small forms have coexisted,
there being no correlation between time and size for the
family as a whole. Herein, small species are regarded as
those which are under 35 mm. in diagonal dimension,
medium size refers to those forms ranging from 35 mm. to
55 mm. in diagonal dimension, and large size refers to those
species over 55 mm. in diagonal dimension. The known
minimum and maximum sizes are represented by the Mid-
dle Ordovician species Ambonychia intermedia Meek and
Worthen (PI. 31, fig. 13) which has a diagonal dimension
of 20 mm. or less, and the Early Devonian species Mytilarca
ponderosa Hall and Whitfield (Pl. 41, fig. 1) with a dia-
gonal length of up to 130 mm.
In the Middle Ordovician, Ambonychiopsis orbicularis
(Emmons) (Pl. 22, fig. 14) is among the largest species,
having a diagonal dimension of up to 70 mm.; while the
Cynthiana species Allonychia flanaganensis Foerste (PI. 20,
fig. 2) ranges up to 100 mm. Among small forms of the Late
Ordovician, Anoptera miseneri Ulrich (PI. 28, fig. 10) has
a diagonal dimension of 30 mm. or less. The upper size
range is represented by such forms as Anomalodonta gigan-
tea Miller (Pl. 27, fig. 2) and Maryonychia concordensis
(Foerste)
diagonal length.
(Pl. 36, fig. 15) which range up to 90 mm. in
The small end of the size scale among Silurian species
is represented by Mytilarca sigilla Hall (Pl. 37, fig. 19)
which is under 20 mm. in diagonal dimension; whereas, the
largest form known to me is a specimen of Amphicoelia
Hall from the Cedarville dolomite of Ohio (U.S.N.M. No.
87509) which measures 100 mm. in diagonal length.
(BIE 365 fice 10) eas
the smallest known Devonian species, being 25 mm. or less
Lophonychia trigonale (Cleland)
in diagonal dimension.
By and large the diagonal dimension is the greatest
dimension of the shell in ambonychiids. However, in a few
GHG Gell, saver,
8) the height and diagonal dimension are approximately of
species such as Mytilarca oviformis (Conrad)
the same magnitude. In addition, in winged types such as
various species of Opisthoptera Meek (PI. 43, fig. 1) the
greatest shell dimension is the length, as measured along
the dorsal margin, rather than the diagonal dimension.
B. ALATION
Almost all genera in the family have been tradition-
ally defined as possessing a posterior alation or at least be-
ing subalate posteriorly. A posterior wing is consistently
present only in the genus Opisthoptera Meek (PI. 43, fig.
7), and two species of Ambonychia Hall, A. elroy: (Hussey)
(Pl. 30, fig. 15) and A. alata Meek (PI. 29, fig. 13).
There is a great deal of confusion in pelecypod mor-
phology as to the correct definitions and applications of
the terms wing, alation, auricle, and the like. In Pectens the
dorsal margin extensions are usually termed auricles, al-
though they are also called ears and wings. In such forms
as Pteria Scopoli the posterior extension of the dorsal mar-
gin is termed a wing or alation, whereas, the anterior ex-
tension is usually called an auricle. Among unionids such
as Proptera alata (Say), the dorsal margin of the shell is
extended upward in a large flange; the term wing is also
applied to this structure.
NortTH AMERICAN AMBONYCHIIDAE: POJETA 139
In order to avoid this confusion of terms the designa-
tion wing, or alation, is restricted in ambonychiids to a
posterodorsal shell extension beyond the shell body proper,
such that the angle formed between the cardinal margin and
the posterior margin is acute (angle beta Text-figure I-5B) .
Such a structure occurs only in the species mentioned above.
In other ambonychiids there is a pronounced lessening of
the convexity of the valves in the posterodorsal part of the
shell (Pl. 51, fig. 15); however, this portion of the shell
never extends farther posteriorly than the posteroventral
part of the shell, such that the angle between the posterior
and dorsal margins becomes acute. It is this reduced postero-
dorsal convexity which traditionally has been called an
alation.
Thus, wing development, rather than being a charac-
teristic feature of the family, is exceptional and is found
only in a handful of species.
C, LINEAR AND ANGULAR SHELL MEASUREMENTS (TEXT-FIGURE I-3-8)
Linear dimensions in ambonychiids are measured as in
other pelecypods. Length is the greatest anterior-posterior
dimension, height is the greatest dorsal-ventral dimension,
and convexity or thickness is the greatest right-left dimen-
sion. In addition to the above measurements, it is usually
convenient to measure the dimension between the dorsal
peak of the umbo and the furthest posteroventral point
on a valve. This dimension has heretofore been called the
greatest dimension of the shell, and in most ambonychiids
it does form the greatest shell dimension. However, in
winged forms the greatest dimension of the shell is usually
along the dorsal margin and equal to the length. Thus, the
term greatest dimension is herein abandoned in ambony-
chiids in favor of diagonal dimension which can be used
both in winged and nonwinged forms with no semantic
contradictions.
Three angular measurements are especially helpful in
the description of ambonychiids; these angles are particu-
larly useful in the separation of species.
The angle between the anterior margin and the dor-
sal margin of the shell (angle gamma) can be measured
with a high degree of accuracy on photographs. In all
cases the dorsal margin is regarded as a straight line
parallel to the hinge axis; the angle the dorsal margin
makes with a line drawn through the furthest anterior
projection of the umbones and the furthest anterior pro-
jection of the shell beneath the umbones is considered to
be angle gamma. In ambonychiids angle gamma varies from
approximately 50 degrees (PI. 42, fig. 7) to about 110 de-
grees (Pl. 24, fig. 3). In the older literature such descrip-
tive terms as erect, oblique, and the like usually refer to
the value of angle gamma, and not to the obliquity of the
shell as indicated by the value of angle alpha. Erect forms
have an angle gamma close to 90 degrees, whereas, oblique
forms have an angle gamma of less than 90 degrees. In
those ambonychiids which possess an anterior lobe, angle
gamma is measured as though the anterior lobe were not
present.
The angle between the dorsal margin and the posterior
margin of the shell (angle beta) is 90 degrees or more in
all nonalate types. In these forms angle beta is usually
poorly defined and can only be measured approximately.
However, in winged species this angle can be measured with
a high degree of accuracy, it is always acute, and the
longer the wing the more acute the anele.
A third angular measurement often used in describing
pelecypod shells is angle alpha. This angle was used with
great success as a morphological criterion in myalinids by
Newell (1942). Newell (1942, p. 24) defined the angle as
follows: “The angle between the midumbonal line and
the cardinal margin is called angle alpha.” He noted
(1942, p. 22) the difficulties in obtaining a precise measure-
ment of the angle because of the flattening out of the um-
bonal ridge in the younger portions of the shell, but felt
that the measurement was sufficiently accurate for the
angle to be a useful morphological criterion.
E. G. Kauffman of the United States National Mu-
seum (personal communication) suggested a method for
obtaining a more precise measurement of angle alpha. In
this method the angle formed by the intersection of the
diagonal or greatest dimension line with the hinge axis is
regarded as angle alpha. In ambonychiids the diagonal di-
mension line bisects the apex of the shell and extends
diagonally to the furthest posteroyentral shell extension.
Usually the furthest posteroventral extension of the shell
is an arc rather than a point; in this case the midpoint of
the arc is used as the point through which to extend the
diagonal dimension line.
Angle alpha is a measure of the obliquity of the shell.
Those forms in which it is less than 90 degrees are re-
garded as having a forward or prosocline obliquity; all
ambonychiids fall into this category. In upright or acline
species the angle is 90 degrees as in Pectens; where the
angle is obtuse as in some Limas (¢.g., Lima (Plicacesta)
Vokes) the obliquity is backward or opisthocline.
Pojeta (1962, p. 172) discussed the concept of shell
obliquity in the ambonychiid genus Ambonychia Hall. He
noted that below the middle of the height of the shell the
umbonal ridge flattens out and cannot be traced beyond
140 PALAEONTOGRAPHICA AMERICANA (V, 30)
this point. To circumvent this difficulty he suggested
that the turning of the shell costae be used as an indicator
of the change in position of the umbonal ridge below the
middle of the height of the shell. This procedure gives
only a general idea of shell obliquity and does not yield
a precise numerical value for angle alpha. In addition, it
has the obvious fault of being limited to forms with radial
prosopon and gives results which differ from those obtained
using the procedure suggested by Kauffman. For these
reasons the method suggested by Pojeta for measuring
ambonychiid shell obliquity is not followed herein, in-
stead the procedure recommended by Kauffman is used.
D, BEAKS AND UMBONES
All ambonychiids have prosogyral beaks (PI. 50, fig.
21), that is, the beaks are turned toward the anterior end
of the shell. In forms lacking an anterior lobe the beaks
are terminal (PI. 30, fig. 21), being located at the anterior
end of the cardinal margin (Text-figure I-2). Most am-
bonychiids having an anterior lobe possess nonterminal
beaks located some distance posterior to the anterior end
of the cardinal margin (PI. 20, fig. 5). In the genus
Congeriomorpha Stoyanow the beaks are described as_be-
ing terminal, and there seems to be a small anterior lobe
remnant located below them. This condition is similar to
that seen in some of the Myalinas.
The umbones of ambonychiids are well developed in
the anterodorsal portion of the shell (Pl. 24, fig. 1). Here
they are raised above the general shell surface and form
a prominent umbonal ridge; however, as this ridge passes
posteroventrally it becomes more and more obscure, until
below the middle of the height it is no longer discern-
ible in most forms (P]. 24, fig. 10). That is, the umbonal
ridge is poorly developed below the point where the nar-
row convexity of the posterodorsal part of the shell broad-
ens out ventrally.
In a number of species there is a flattening of the
anterodorsal part of the shell with a keeling of the ad-
jacent umbones. This carination is especially well devel-
oped in the larger species of the Ordovician genus Ambony-
chia Hall (Pojeta, 1962), however, it is also found in
species of Gosseletia Barrois (Pl. 35, fig. 9), Lophonychia
Pohl (PI. 36, fig. 5), and others. In most species the um-
bones remain rounded anteriorly.
Shell obliquity as indicated by the intersection of the
midumbonal line and the dorsal margin is discussed in
the preceding section on Linear and Angular Measure-
ments, In some species of Opisthoptera Meek a midum-
bonal keel rather than an anterior carination is developed
(Pl. 43, fig. 8); this keel extends to the ventral margin of
the shell and indicates the ontogenetic variation of the
position of the umbo. In these species a precise value of
angle alpha can be obtained from the intersection of the
midumbonal line and the dorsal margin. However, for the
sake of consistency, and because all species of O pisthoptera
do not possess a midumbonal keel, the procedure recom-
mended above for the measurement of angle alpha is also
followed in all species of Opisthoptera.
E. PROSOPON
All ambonychiids possess concentric growth varices
and these are usually of two types; there are the fine close-
ly spaced growth lines (Pl. 47, fig. 1), and the less fre-
quent more coarse growth laminae which indicate more
prolonged stoppages of growth for various reasons (PI. 29,
fig. 10). These coarser growth lines often are poorly de-
veloped either in the sense of being few in number, or in
being only barely distinguishable from the finer laminae.
In some species, such as Cleionychia undata (Emmons)
(Pl. 34, fig. 2), broad, often poorly defined concentric un-
dulations cross the shell independently of the growth lines
and radial prosopon. ‘These concentric undulations are best
developed in various Middle Ordovician species, although
they occur in a few younger forms, such as species of the
Silurian genus Amphicoclia Hall.
Radial prosopon is a characteristic feature of many
ambonychiid genera. This ribbing is superimposed upon
the growth varices and concentric undulations. As far as
known, in all well-preserved material both fine and coarse
growth varices cross the ribs as well as the interspaces be-
tween them. In particular, the fine varices are often weath-
ered off the raised ribs (PI. 47, fig. 1).
Ribbing in ambonychiids consists of two types which
merge imperceptibly into each other. There are either nu-
(Pl. 24, fig. 2) or less numerous
coarser costae (PI. 29, fig. 18). As an arbitrary standard
costae are regarded as being one mm. or more in width,
whereas, costellae are less than one mm. wide. However, the
two types of radial prosopon are not always readily sep-
arable, and the early dissoconch stages of all costate genera
merous fine costellae
possess ribs which are less than one mm. wide,
Costellae are found in such North American forms as
the Middle Ordovician genus Ambonychiopsis Isberg (PI.
23, fig. 5) and some species of the Silurian genus Amphi-
coclia Hall (Pl. 25, fig. 2). Costate genera are character-
istic of the Upper Ordovician rocks of North America and
include such forms as Anomalodonta Miller (PI. 28, fig. 4) ,
Ambonychia Hall (PI. 31, fig. 19), and Maryonychia, n. g.
NortTH AMERICAN AMBONYCHIIDAE: POJETA 141
(Pl. 36, fig. 11). Costae are also present in the Devonian
genus Byssopteria Hall (PI. 32, fig. 6) and some species of
the Silurian genus Amphicoelia.
Only four genera are known to be multicostate. Foll-
mannia Drevermann is an Eurasian genus which previously
has been reported only from the Devonian of Germany
and the Ardennes area of France, Belgium, and Luxem-
bourg. At the United States National Museum there are
several specimens from the Devonian rocks of Liu Koping
and Yunnan, China, which appear to be assignable to Foll-
mannia (PI. 35, fig. 5). These specimens are not so elongate
as those figured by Drevermann (1907) and Frech (1891)
but compare favorably to a juvenile specimen of Follmannia
pseudalectryonia (Frech) figured by Maillieux (1937).
The other genera of multicostate ambonychiids are
found in North America: Maryonychia, n. g. and O pisthop-
tera Meek are Ordovician forms, while Byssopteria Hall
is a Devonian genus. Opisthoptera is essentially a costellate
genus, whereas, Maryonychia and Byssopteria are costate
genera. All three genera have both bifurcating and inter-
calating ribs, the exact patterns of which are described in
the discussion of each genus.
Except for the above mentioned forms, rib bifurca-
tions and intercalations are individual features which char-
acterize no particular genera or species and have no con--
stancy of occurrence.
As far as known costae occur only in the outer shell
layer but are not surface features of this layer, rather they
involve corrugation of the entire outer ostracum. The inner
ostracum is deposited as a more or less callous-like layer
covering over the costae on their inner side. As the ani-
mal aged the inner shell layer became progressively thicker
and eventually obscured the costae completely except at
the muscle markings (where only a thin hypostracum sep-
arated the muscle from the inner surface of the outer ostra-
cum), and around the edge of the shell (7.e., the youngest
part) where the inner ostracum was not yet thick enough
to totally obscure the costae. The above description is based
primarily upon Late Ordovician forms; it is presumed that
the costae of species before and after this time were similar,
but this has not yet been demonstrated.
Only in some species of the genera Ambonychiopsis
Isberg does the combination of radial and concentric proso-
pon result in cancellate prosopon; otherwise cancellate
sculpture is not known in ambonychiids.
The above mentioned umbonal keels form a variety
of prosopon found in a minority of species.
Lastly, the tuberculate prosopon described in an un-
named ambonychiid by Pojeta (1962, p. 174) is probably
an encrustation of the labechiid Dermatostroma Parks.
F. BYSSAL APPARATUS
The external expression of a byssus takes two forms:
a) the possession of a pronounced byssal gape (Text-figure
1-7), a feature especially prominent in North American
Late Ordovician forms, and b) the presence of a byssal
sinus, an indentation seen in lateral view, in the antero-
dorsal part of the shell at the point where the byssal fibers
leave the shell.
The byssal gape is the most obvious expression of the
possession of a byssus but occurs in a minority of the genera
in the family. The gape is a space between the right and
left valves in the dorsal portion of the anterior face around
which the shell curves (Pl. 30, fig. 3). Thus, this space
had no shell covering, but rather was plugged by the byssal
fibers which existed at this point. The gape is bilaterally
symmetrical, half of its width being located in each valve.
In Anomalodonta Miller (PI. 27, fig. 6) and Maryonychia,
n. g. (Pl. 36, fig. 14) the gape is rather long and wide;
whereas, in Opisthoptera Meek (PI. 44, fig. 16) the byssal
gape is small in both length and width. This suggests that
the byssus was better developed in Anomalodonta and
Maryonychia than in Opisthoptera. Correlated with this
difference in the development of the byssal gape is the
presence of large, well-developed anterior and_ posterior
byssal retractor muscles in Anomalodonta (PI. 27, figs. 2-7) ,
while in Opisthoptera these muscles are much smaller (PI.
43, figs. 11 and 22).
indicate that Anomalodonta had more ability to adjust
itself on the byssal anchorage than did Opisthoptera.
Generally a prominent byssal gape is found only in
Alternatively these differences may
forms with radial prosopon, however, not all ribbed genera
possess a pronounced byssal gape. Only two North American
genera with concentric prosopon show a readily discern-
ible byssal gape: the poorly known Late Ordovician genus
Psilonychia Ulrich (PI. 46, fig. 6) and the Late Devonian
genus Congeriomorpha Stoyanow.
The usual shape of the byssal gape is fusiform (PI. 30,
fig. 3), although in some specimens of Ambonychia obesa
(Ulrich) it is almost round. Likewise, the gape may be
flush with the anterior face (PI. 36, fig. 12), or it may be
depressed below the general anterior surface (PI. 31, fig. 8) .
In a number of genera the anterior face is poorly
known, and the presence or absence of a discernible byssal
gape cannot be ascertained.
The byssal sinus is prominent in many species of
Ambonychia Hall (Pojeta, 1962), Anoptera Ulrich (PI. 29,
fig. 2), Cletonychia Ulrich (PI. 33, fig. 22), Mytilarca Hall
and Whitfield (PI. 41, fig. 4), and others. The degree of
prominence of the byssal sinus is variable, and different
species of the same genus may vary widely in the expres-
142 PALAEONTOGRAPHICA AMERICANA (V, 36)
sion of this feature. Thus, Ambonychia byrnesi (Ulrich)
has almost no byssal sinus (PI. 31, fig. 19), although it has
a prominent byssal gape; other species of Ambonychia show
both structures prominently.
In those forms which appear to lack a byssal gape, it
is only that the gape is small, as in the modern forms
Mytilus Linné and Modiolus Lamarck, rather than being
absent. In neither of these living genera is the shell strongly
distorted laterally at the place where the byssus exists, how-
ever, both are well-known byssate forms and may possess
a prominent byssal sinus. In at least some of the species of
ambonychiids which appear to lack a byssal gape (¢.g.,
Cleionychia lamellosa (Hall) ; PI.
of muscle scars formed by byssal retractors indicates that a
33, fig. 3), the presence
small nondiscernible byssal gape was present. ‘The presence
of a byssal sinus and the severe reduction of the anterior
end also indicate that ambonychiids were attached by a
byssus.
G. SHELL STRUCTURE
In no ambonychiid is the shell microstructure known.
Generally shelled specimens show various details of mor-
phology which cannot be observed on molds and_ casts,
and one is reluctant to section such materials. However,
thin sectioning of some of the shelled Ordovician materials
at the author’s disposal revealed no shelled microstructure,
only coarse recrystallized calcite.
As far as known the ambonychiid shell is composed of
two calcareous layers, the inner and outer ostraca. This is
definitely shown in several specimens of Anomalodonta
gigantea Miller (PI. 26, fig. 14) and surmised from strong
indirect evidence in Ambonychia Hall and Opisthoptera
Meek.
‘The mineralogical composition of the inner and outer
ostraca is problematic. Specimens of Ambonychia are
known in which only the outer shell layer is preserved,
suggesting that this layer was more stable than the inner
ostracum. On this basis, the outer ostracum could be re-
garded as calcitic and the inner ostracum as aragonitic.
Additionally, composite molds of Ambonychia (Pojeta,
1962, pl. 23, fig. 6), Anomalodonta (Pl. 27, fig. 5), and
Opisthoptera (PI. 44, fig. 15) are known. These suggest
that after the shell was filled with sediment the inner
shell layer was dissolved away and the filling remained plas-
tic enough for the inner face of the outer ostracum to be
impressed upon the internal mold. Alternatively, the entire
shell may have been dissolved away forming a steinkern,
with the mold of the exterior then being impressed upon
the internal mold during compaction. The former alterna-
tive suggests a difference in the stability of the shell layers,
the latter does not.
In most ambonychiids the shell is seldom preserved.
Even in the genus Ambonychia, where specimens preserving
only the outer layer are known, there are horizons in which
none of the specimens of this genus preserve any shell
material; while the brachiopods, ectoprocts, and other cal-
citic fossils in these horizons always have the shell material
preserved. ‘These factors suggest that the shell of ambony-
chiids was unstable and probably aragonitic.
The overall picture appears to favor the hypothesis
that both the inner and outer ostraca of ambonychiids
were mineralogically unstable, and that they are only pre-
served when they have been replaced by more stable min-
erals.
The thickest part of the ambonychiid shell is in the
upper portion of the umbones, that is, in the oldest part
of the shell (PI. 26, fig. 14). In adult specimens of Anomalo-
donta gigantea Miller the shell is 5-6 mm. thick in this
region. Because 4. gigantea is one of the larger species, this
thickness probably represents more or less of a maximum
value for the family. From the upper umbo of a valve
the shell thins rapidly in all directions; halfway down the
diagonal dimension of A. gigantea it is only about one mm.
thick (PI. 26, fig. 14). Thus, over the greater part of the
body of the animal the shell is relatively thin, and it may
become so thin that the inner ostracum no longer obscures
the shell costae completely. However, the extreme anterior
and posterior edges of the shell are thickened, and are
thicker than the portion of the shell between them (PI. 28,
fig. 3). The extreme anterior and posterior edges also pos-
sess a series of grooves and ridges (Pl. 28, fig. 8) similar
to those seen in Pinctada margaritifera (Linné) . These mar-
ginal grooves and ridges are further discussed below in the
section dealing with the ligamental area.
A feature known only from Late Ordovician molds and
casts of ambonychiids is a brown to jet black organic film
which often covers the specimens. The film does not occur
in the matrix around the specimen, but only covering the
individual organism, and undoubtedly was originally part
of the animal. This organic film may indicate the presence
of a heavy periostracum which originally covered the cal-
careous shell, or it may represent remnants of large amounts
of organic matter which was originally in the shell substance
itself.
3oth of these conditions are known to occur in living
byssate pelecypods, however, which of the two conditions
obtained in ambonychiids is uncertain. Unweathered
shelled specimens are often as dark as molds and casts, al-
though the shelled materials are never jet black as is true
of many molds and casts. Broken surfaces of shelled ma-
terials are not only dark at the surface but are dark
NorTH AMERICAN AMBONYCHIIDAE: POJETA 143
throughout, and perhaps the organic film represents rem-
nants of both the periostracum and the conchiolin which
was in the shell substance itself.
While no hypostracal layer has been seen in the shell
substance itself, it is known from internal molds that at
best there was only a thin layer of shell separating the
muscles from the outer ostracum. In internal molds the
markings of the shell prosopon can be seen on the posterior
muscle markings but not on the shell surrounding the
musculature (Pojeta, 1962, pl. 23, fig. 1). Thus, either there
was nothing separating the muscles from the inner surface
of the outer ostracum, or the muscles secreted a thin hyp-
ostracum between themselves and the outer ostracum. Be-
cause the latter is the normal condition among pelecypods,
it is also presumed to be so here.
The above description is based almost entirely upon
Late Ordovician forms; I had few post-Ordovician shelled
specimens at my disposal. Undoubtedly much of the de-
scription is applicable to all ambonychiids, but only new
materials will determine which particulars are not ap-
plicable
Two of the type specimens of Anomalodonta gigantea
Miller show the two ostracal layers, and in each specimen
both layers have a rather coarse prismatic structure (PI. 25,
figs. 7, 10). This coarse prismatic structure differs from the
more typical massive replacement structure seen in other
shelled specimens (Pl. 26, fig. 14). At the present time it
cannot be determined if the prismatic structure of the type
specimens represents any of the original shell microstruc-
ture. A prismatic outer ostracal layer occurs in many pelecy-
pods, and in at least one family, the Anatinidae, there is
a prismatic layer under the nacreous one (Schenck, 1934,
joe. WA).
In summary, the ostracum of ambonychiids consists of
two layers, an inner ostracum and an outer ostracum. The
microstructure of neither layer is known, the inner ostra-
cum was apparently aragonitic, and the outer ostracum
may also have been aragonitic. Covering the ostracum there
was probably a fairly thick periostracum; there may also
have been significant amounts of organic matter in the
calcareous shell substance. Underlying the muscle scars
there was a fourth shell layer, the hypostracum.
Il. INTERNAL FEATURES (Text-figure IT)
A, LIGAMENTAL AREA
The ambonychiid ligament contained both tensional
and compressional elements. It is herein arbitrarily dis-
cussed under internal features.
The ligamental area is known in a number of am-
bonychiid genera of various ages from both North America
and Europe. In North America it is known in the Ordo-
vician genera Ambonychia Hall (Pl. 30, fig. 21), Anomalo-
donta Miller (Pl. 28, fig. 8), and Opisthoptera Meek (PI.
45, fig. 1); in the Silurian from representatives of the gen-
era Mytilarca Hall and Whitfield (Pl. 37, fig. 22) and
Amphicoelia Hall; and in the Devonian from species of
Mytilarca (Pl. 38, fig. 10) and Gosseletia Barrois (Pl. 36,
fig. 4).
In all of the species where the ligamental area is known,
a typical duplivincular ligament is indicated. That is, the
ligamental area is crossed longitudinally by a series of al-
ternating grooves and ridges. As developed in living forms
(e.g., Arca Linné) the ligamental grooves represent the in-
sertions of separate parallel sheets of laminar ligamental
material which has great elasticity to the tensile stresses
exerted by the adductor muscles. Upon relaxation of the
adductors the laminar sheets contract and help pull the
valves apart. The areas between the ligamental grooves (7.e.,
the ligamental ridges of ambonychiids) , as well as the junc-
tion of the two valves along the hinge line, are covered by
fibrous ligamental material similar to the resilium of such
forms as Nucula Lamarck. This fibrous ligamental material
is weak to tensional stresses but responds readily to com-
pressional stresses. The entire portion of the fibrous ma-
terial above the hinge axis does not function in opening
the valves, because only noncompressional stresses are ap-
plied above the hinge axis. However, below the hinge axis
the fibrous ligamental material is compressed when the
adductors contract, and upon relaxation of the muscles it
springs Outward and helps to open the valves. (See New-
ell, 1938 and 1942, for a more extensive discussion of the
duplivincular ligament.) Undoubtedly the ligament of
ambonychiids functioned in a manner similar to that of
Arca Linné, as indicated by the close structural similarity
of the ligamental areas in the two groups.
Generally among Ordovician forms the ligamental
grooves and ridges are relatively coarse and fewer in num-
ber (PI. 30, fig. 21) than in Devonian species where the
ligamental imprints are finer and more numerous (PI. 41,
fig. 7).
Most ambonychiids have an entirely opisthodetic liga-
ment, the grooves and ridges being located below and _be-
hind the beaks (PI. 28, fig. 8). Isberg (1954, pl. 7, fig. 2d)
showed a specimen of Ambonychinia? pediculata Isberg
which has an amphidetic ligament; the ligamental grooves
and ridges being continued onto the anterior lobe. In none
of the anteriorly lobed North American forms are the liga-
mental grooves and ridges known to extend onto the lobe.
However, in none of them is the ligamental area known in
S)
Text-figure Il: Semidiagrammatic reconstructions of the morpho-
logically better known ambonychiid genera: A-cardinal teeth,
B-anterior byssal retractor muscle scar, C—posterior byssal-pedal re-
tractor muscle scar, D—posterior adductor muscle scar, E-pallial line,
F-duplivincular ligament, G—posterior lateral teeth, H—wing, I-byssal
gape, and J—anterior commissure. The anterior byssal retractor muscle
scars are displaced ventrally for reasons of illustration. 1-2. dmbony-
chia; The reconstruction of this genus is changed from that of
6
Pojeta, 1962, based upon new better preserved material. The posterior
lateral teeth are based upon A. radiata where they are subparallel
to the cardinal margin; 1—medial view of left valve, 2—-anterior view.
3-4. Opisthoptera: The stippled area along the cardinal margin indi-
cates the portion of the ligamental area which has not been observed;
3-anterior view, 4-medial view of left valve. 5-6. dnomalodonta: This
genus is similar to dmbonychia, differing only in dental structure ;5-
medial view of right valve, 6-anterior view.
NortH AMERICAN AMBONYCHIIDAE: POJETA 145
its entirety, and an amphidetic ligament may eventually be
described in these species.
The ligamental area is best known in the Late Ordo-
vician species Ambonychia alata Meek (PI. 30, fig. 21) and
Anomalodonta gigantea Miller (PI. 28, fig. 8). A. gigantea
will serve as a more or less typical example. In this species
the ligamental area is wide dorsoventrally and crossed by
coarse longitudinal grooves and ridges (Pl. 27, fig. 1). Pos-
teriorly the grooves and ridges extend to the extremity of
the dorsal margin and near their termination turn gently
ventrad (Pl. 28, fig. 8). Anteriorly, just before their ter-
mination, the grooves and ridges make a sudden ventrally
directed turn (PI. 28, fig. 8; Pl. 30, fig. 21). In weathered
or poorly prepared materials the anterior ventral turning
of the grooves and ridges is planed off, and the remnants
may have the general appearance of a tooth, as in Miller's
original types of Anomalodonta gigantea (PI. 26, fig. 6).
This is not a part of the dentition; in well-preserved ma-
terial the cardinal dentition is located below the duplivin-
cular ligament and does not cross the ligamental area (PI.
30, fig. 1). The arrangement of ligamental grooves and
ridges in Ambonychia alata Meek (PI. 30, fig. 21) is simi-
lar to that of Anomalodonta gigantea. The ligamental areas
of the two valves diverge upward at varying angles and in
different species produce ligamental spaces of varying
widths.
In all ambonychiids with cardinal teeth, the teeth are
located on a vertical lamella beneath the ligamental area
(PI. 30, fig. 21); this lamella may extend posteriorly be-
neath the duplivincular ligament for an undetermined
length (PI. 30, fig. 21). Posterior lateral teeth are also lo-
cated below the ligamental area; they may be attached di-
rectly to the inner face of the inner ostracum as in Ambony-
chia alata Meek (PI. 30, fig. 16) and Ambonychia radiata
Hall (Pojeta, 1962, pl. 23, fig. 14), or they may be attached
to what is either a separate vertical lamella or a pronounced
thickening of the inner ostracum as in Mytilarca dalhousei
Clarke (PI. 38, fig. 14).
Ambonychia cultrata (Ulrich) has been described as
“channel-
like” ligament. It was thought that its ligament might be
lacking ligamental grooves, and having instead a
more or less similar to that of Anadara pexata (Say), which
has a large fibrous portion to the ligament and only one
laminar sheet. New materials of this species now show that
a typical duplivincular ligament is present (PI. 32, fig. 1).
The ligamental “channel” figured by Ulrich (1893 (1895) ,
pl. 45, figs. 6-7) and Pojeta (1962, pl. 25, figs. 9-10) repre-
sents a collapsed duplivincular ligamental area. Often in
shelled ambonychiids from the Upper Ordovician rocks of
the Cincinnati, Ohio area, the ligamental area is com-
pressed dorsoventrally with the beak coming to rest on top
of the cardinal teeth. This process obliterates the duphi-
vincular grooves and ridges or confines them to a smaller
space than they normally occupy (PI. 30, figs. 8, 18) ; when
better materials are obtained the duplivincular ligament is
found (PI. 30, fig. 21). The collapsed ligamental area often
has the appearance of being “channel-like.”
The genus Streptomytilus Kindle and Breger is based
upon poor material, and the major taxobasis separating this
genus from other ambonychiids is the presumed lack of a
duplivincular ligament. I have seen the type material
of the three species originally assigned to the genus, and
in none of these species is the portion of the shell which
normally preserves the ligamental structures present. ‘The
taxobasis used by Kindle and Breger is probably invalid,
and the genus is not herein recognized. The generic name
Streptomytilus is discussed further in the taxonomic por-
tion of the present work.
The duplivincular ligament is also known in the Early
Paleozoic families Cyrtodontidae and Pterineidae, and in
the Late Paleozoic Myalinidae and pectinoids. ‘This struc-
ture may indicate a relationship between these families.
Around the growing edge of the shell in Ambonychia
Hall and Anomalodonta Miller there is a series of prom-
inent marginal grooves and ridges (PI. 28, fig. 8; Pl. 31, fig.
11). These grooves and ridges are especially prominent
along the anteromedial (Pl. 51, fig. 11) and extreme pos-
terior (PI. 28, fig. 7) edges of the shell. They are similar
to marginal grooves and ridges figured by Newell (1942) in
myalinids and to grooves and ridges which occur around
the growing edge of the Recent species Pinctada margariti-
fera (Linné). In this species the grooves and ridges result
from the subdivision of the prismatic outer ostracum, they
are especially numerous in the area of the byssal gape and
sinus. Because of these grooves and ridges the edge of the
shell appears to be exfoliating, and in at least some speci-
mens of ambonychiids there is a gradual transformation of
the marginal grooves and ridges into the typical shell proso-
pon (PI. 31, fig. 11).
Isberg (1934) figured several specimens of ambony-
chiids in which the ligamental grooves and ridges are con-
tinuous with the marginal grooves and ridges, both an-
teriorly and posteriorly (e.g., pl. 28, figs. Id, 2c, 3c). In
none of the North American material seen by me, have I
been able to establish a continuation of the ligamental
grooves and ridges with those of the marginal grooves and
ridges. It is difficult to imagine the continuation of the liga-
mental structures away from the dorsal margin as this is
not known to occur in other pelecypods.
The marginal grooves and ridges in ambonychiids are
146 PALAEONTOGRAPHICA AMERICANA (V, 36)
a phenomenon of the growing edge of the shell. They may
represent a subdivision of the outer shell layer as occurs
in Pinctada margaritifera or perhaps a series of closely
spaced growth lines; it is doubtful that they represent liga-
mental continuations.
B. MUSCLE MARKINGS
Except in Ordovician species, muscle markings of all
types are poorly known in the Ambonychiidae. There are
occasional reports of various muscle scars in Silurian and
Devonian species, but generally the musculature of these
forms is poorly known. Thus, the following discussion is
based primarily upon Ordovician species; post-Ordovician
representatives are included whenever possible.
1. Pallial
forms are known in which there is a pallial sinus. There is
line—Ambonychiids are integropalliate; no
sometimes a slight anteriorly directed indentation in the
posterior most portion of the pallial line (PI. 26, fig. 12) ;
this may indicate an incipient pallial sinus, if so, it is small.
The pallial line is discontinuous throughout most of
its length. That is, the muscle fibers of the mantle were
gathered into a number of separate insertion centers, sep-
arated by areas where the mantle was not attached (PI. 27,
fig. 6). Usually just ventral to the posterior adductor muscle
scar the pallial line attachment is continuous (PI. 31, fig.
1), or near continuous (PI. 26, fig. 12). In the latter case
the individual points of attachment are close together.
The pallial line begins near the posterior end of the
posterior adductor muscle scar (PI. 31, fig. 2), passes ven-
trally for a short distance, then turns anteriorly (PI. 26,
fig. 12), and finally passes up the anterior face of the um-
bon (RIE 27, fig.16)\-
in the umbonal cavity just below the beak (PI. 27, fig. 6) ;
in heteromyarian forms it should terminate at the anterior
adductor, however, this has not yet been observed.
The pallial line is well known only in the Late Ordo-
viclan genera Opisthoptera Meek (Pl. 44, fig. 12), Am-
bonychia Hall (PI. 31, fig. 1), and Anomalodonta Miller
(Pl. 26, fig. 12). All three of these genera possess a dis-
In monomyarian forms it terminates
cernible byssal gape, and usually the pallial line is dis-
placed laterally in the region of the gape (PI. 26, fig. 12).
The lateral displacement is more prominent in Anomalo-
donta (P1. 27, fig. 3), than in either of the other two genera
(EN, 4Be nutes, 2)
In Opisthoptera the portion of the pallial line ventral
and anterior to the posterior adductor muscle scar is not
so well known as the segment which passes up the anterior
face. The points of pallial attachment in Opisthoptera are
usually smaller than in the other genera, and often are so
close that the pallial line appears to be almost continuous
(Bs etioe 2) ie
In the Middle Ordovician genus Cleionychia Ulrich,
on the lateral and posterior umbonal regions of internal
and composite molds, there is often a series of arcuate
ridges radiating Outward from the apex of the shell (PI. 33,
fig. 25). In at least some cases these arcuate ridges are dis-
continuous (Pl. 33, fig. 25), and they may represent at-
tachment of the mantle inside the limits of the pallial line.
Newell (1942, p. 31) described such attachments as follows:
Some of the Myalinidae show irregularly disposed fine pits or
punctations of the inner surface of the shell inside the limits of the
pallial line. Similar pits are common in some of the Early Paleozoic
Ambonychiidae. Living Mytilidae are relatively thin-shelled, so that
distinct muscle marks are commonly lacking in the shells. However,
an occasional Mytilus or Volsella [Modiolus] exhibits similar puncta-
tions. In some instances they are more or less regularly disposed in
radial rows. Microscopic examination of the mantle of such animals
indicates that these punctations represent the insertions of tiny bits
of outer surface of the mantle where it is attached to the shell...
The arcuate ridges of Cleionychia molds may represent
such attachments of the general surface of the mantle.
In one specimen of Cleionychia on the anterolateral
umbonal face there is a discontinuous arcuate ridge (PI.
33, fig. 5), and just before this ridge fades out it turns in
the general direction of the posterior adductor muscle
scar. This ridge may be a portion of the pallial line; if so,
then the pallial line of Cleionychia differs from Late Ordo-
vician ambonychiids in passing up the lateral face of the
umbonal ridge, rather than the anterior face of the shell.
Various authors describe the pallial line of different
species of ambonychiids as being regular, unbroken, mar-
ginal, simple, and the like. However, almost to a man they
do not describe what they mean by such adjectives, nor do
they figure the pallial line. As far as known to me the
pallial line of ambonychiids is always broken (7.c., dis-
continuous) , and it is not marginal in the sense that it is
moved inward some distance from the shell edge; the
pallial line is both regular and simple in that there is no
pallial sinus,
2. Adductor system. — The posterior adductor muscle scar is
known in numerous ambonychiid species, and all forms
presumably possessed this muscle. ‘The anterior adductor
muscle of ambonychiids is either markedly reduced or
entirely absent. Thus, all members of the family are either
heteromyarian or monomyarian.
The best known heteromyarian form is the Devonian
genus Gosseletia Barrois (PI. 36, fig. 1), in which a prom-
inent anterior adductor muscle scar has been observed by
several authors. An anterior adductor muscle scar may be
found in any of the anteriorly lobed species, however, this
scar has not yet been observed in most such forms. No
NortH AMERICAN AMBONYCHIIDAE: POJETA 147
ambonychiids lacking an anterior lobe are known to have
an anterior adductor, although this situation obtains in
species of the Recent genus Mytilus Linné; until we obtain
more knowledge of the pallial line of most of these forms
it will not be possible to state unequivocally that they lack
an anterior adductor.
The posterior adductor muscle scar is large and usu-
ally located in one of two places, either on the posterodor-
99
sal part of the shell (Pl. 33,
the middle of the height and slightly posterior to the middle
fig. 10) or subcentrally near
of the length of the shell (PI. 27, fig. 2). The more central
the position of the posterior adductor, the more reduced is
the anterior adductor and the anterior end of the shell.
This is a common occurrence in many groups of pelecypods
such as the ostreids, pectinids, and pteriids, where, as the
anterior end became reduced, selection against the mechani-
cal disadvantage of having a single adductor muscle in
the posterodorsal portion of the shell results in the move-
ment of the posterior adductor into a subcentral position.
The adductor seldom ends up in the exact center of the
shell, and in some groups such as the Limas it remains
some distance from the shell center.
Among ambonychiids the posterior adductor is sub-
central in Anomalodonta Miller (Pl. 27, fig. 5), Ambony-
chia Hall (PI. 30, fig. 16), and Opisthoptera Meek (PI. 43
fig. 22); in all of these genera there is no sign of an an-
terior lobe or an anterior adductor. In those species of
Opisthoptera with large wings (PI. 45, fig. 4), the posterior
adductor muscle scar lies anterior to the middle of the
length, just above the middle of the height of the shell. In
such forms the posterior adductor muscle scar lies just
behind the center of the body of the shell, and it is only
the development of the exceptionally large posterior wing
which causes it to appear to be misplaced.
In the anteriorly lobed Middle Ordovician genus Am-
bonychiopsis Isberg, the posterior adductor has begun moy-
ing toward the center of the shell, however, it is still in
the posterodorsal portion of the shell (PI. 22, fig. 18).
The posterior adductor scar has also been observed in
several other ambonychiid genera, however, it is well pre-
served only in the Middle Ordovician genus Cleionychia
Ulrich (PI. 33, fig. 1) and the Middle Devonian genus
Lophonychia Pohl (Pl. 36, fig. 5). This muscle scar is
known from fragmentary remains in Allonychia Ulrich (PI.
19, fig. 5) and Amphicoelia Hall (Pl. 24, fig. 10).
In Cleionychia the posterior adductor scar is located
in the posterodorsal part of the shell above the middle of
the height (PI. 33, fig. 22). Several specimens of the genus
preserving the anterior face (PI. 33, fig. 9), anterior byssal
retractor scars (PI. 33, fig. 3), and posterior adductor scar
(Pl. 33, fig. 1) are known. However, none of these speci-
mens show an anterior adductor muscle scar or an anterior
lobe, and it is difficult to account for the apparent mis-
placement of the posterior adductor scar. Perhaps a small
anterior adductor muscle scar will eventually be found, or
perhaps in Cleionychia as in Lima Bruguiére the posterior
adductor muscle never assumed a typical subcentral posi-
tion.
Lophonychia Pohl (Pl. 36, fig. 5) shows a posterior
adductor scar located at about the middle of the height but
near the posterior end of the shell. In this genus the move-
ment of the posterior adductor has been primarily in a
ventral direction, rather than to a subcentral position.
Ulrich (1894, pp. 489, 498) wrote of the presence of
what he termed an anterior subrostral clavicle in the genus
Ambonychiopsis. His description of this structure was as
follows:
. A thin plate passes vertically down from the anterior end
of the hinge plate separating a small lobe, immediately beneath and
sometimes a little in front of the beaks, from the umbonal cavity.
tsbere (1934, p. 29)
Ambonychinia Isberg also wrote of a clavicular shell pro-
in the description of the genus
jection extending downward from the ligamental plate and
separating the anterior adductor muscle scar from the um-
bonal cavity. He discussed the presence of a similar struc-
ture in the European species of Ambonychiopsis (1934,
p. 82).
In the nuculoid genera Cleidophorus Hall and Nucu-
lites Conrad, the older authors often wrote of a structure
which they called a clavicle. In these genera the clavicle
is an internal rib extending almost directly downward from
the anterior portion of the dorsal margin; it is often located
immediately behind the anterior adductor. This so-called
clavicle is probably the same type of structure as the thick-
ened internal rib found in the Recent solenid genus Siliqua
Megerle von Mihlfeld.
The structure which Ulrich regarded as a clavicle in
Ambonychiopsis is known only from internal molds, and
is the space between the anterior lobe and the umbo of a
valve (Pl. 22, fig. 12; Pl. 23, fig. 2). The width of this
space varies in different species of Ambonychiopsis (PI.
22, fig. 12; Pl. 22, fig. 13). In addition, the width of the
space varies in different specimens of the same species (PI.
22, fig. 13; Pl. 23, fig. 2), depending upon how far medially
the umbones have been displaced during preservation. In
such other anteriorly lobed genera as Allonychia Ulvich
(PI. 20, figs. 3, 9) there is no prominent incised area be-
tween the anterior lobe and the umbo.
Whether this incised area was made by a simple shell
148 PALAEONTOGRAPHICA AMERICANA (V, 36)
thickening, or by an umbonal septum such as occurs in the
Permian myalinid Atomodesma Beyrich and the Recent
genera Septifer Récluz and Congeria Partsch cannot be de-
termined from the materials at hand. Rubber casts of Am-
bonychiopsis molds show only a slight’ shell thickening,
however, it is difficult to force viscous molding compounds
into the narrow space between the umbo and the anterior
lobe. In several specimens of the Trentonian species Am-
bonychiopsis orbicularis (Emmons) there are remains of re-
crystallized shell material extending along the length of the
medial face of the upper umbo, suggesting that some-
thing of the nature of an umbonal septum was present.
This recrystallized shell material has not been seen from
a medial aspect, but only on either side of the umbonal
ridge in molds where the medial face of the specimen was
in apposition with the sediment. Additionally, in internal
rubber molds of Septifer and Congeria the umbonal sep-
tum produces a space between the filling of the umbo
and the margin of the shell which is reminiscent of the
space seen in Ambonychiopsis. ‘The problem of the origin
of this space in Ambonychiopsis cannot be solved until
specimens preserving the shell in the upper umbonal area
are found.
Isberg (1934, pl. 1,
Ambonychinia radiata Isberg depicts a thickened internal
fie. 8) in a figure of the species
rib immediately behind what appears to be a shelf floor-
ing the anterior lobe.
Stoyanow (1948, pp. 784-786) in his Devonian genus
Congeriomorpha described what he termed a subumbonal
myophoric depression. As figured this structure appears
to be an umbonal septum such as occurs in the Permian
and Recent genera mentioned above. Stoyanow felt that
the subumbonal myophoric depression in Congeriomorpha
is the same type of structure as the umbonal septum of
other forms, however, he held that (p. 785) :
None of these terms [various names which have been applied to
the umbonal septum] is applicable to the homologous structure in
Congeriomorpha for the simple reason that in this genus the space
corresponding to the umbonal cavity is completely filled with shelly
matter and, therefore, there is no umbonal cavity, and consequently,
no septum or plate.
I have not seen Stoyanow’s original specimens, however,
it would seem that the subumbonal myophoric depres-
sion and the umbonal septum are the same type of mor-
phological structure and Stoyanow’s distinction between
them is not recognized herein.
In at least the left valve of Congeriomorpha, the um-
bonal septum is divided into two parts by an oblique ridge.
Stoyanow (p. 786) postulated that the portion of the sep-
tum anterior to the ridge served as the insertion of the an-
terior adductor muscle, while the portion posterior to the
ridge served for the attachment of what he calls the anterior
retractor. Stoyanow’s suggestion that the umbonal septum
of Congeriomorpha may have been the site of insertion of
some of the shell musculature is a distinct possibility. The
septum is known to function in this capacity in some
pelecypods such as the dreissensiids; however, his analysis
must be considered as tentative, pending the determina-
tion of the course of the pallial line.
3. Retractor muscles. —In a number of Ordovician genera,
and perhaps in the Silurian genus Amphicoclia Hall, an ad-
ditional muscle scar (or scars) is present behind the beak
of each valve. In living mytilaceans such scars are made
by the anterior byssal retractor muscles. Newell (1942)
considered similarly placed scars in myalinids to represent
the origins of anterior byssal retractors. Doubtless the scars
in ambonychiids were formed by muscles having the same
function, namely the retraction of the byssus.
As far as known in ambonychiids there are either one
or two such scars in each valve. In the latter case the scars
probably represent the origin of a bifid anterior byssal re-
tractor muscle. In Anomalodonta gigantea Miller (Pl. 27,
fig. 7), Anoptera miseneri Ulrich (Pl. 29, fig. 5), and
others the anterior byssal retractor has a bifid origin in
the shell. In Allonychia flanaganensis Foerste (PI. 21, fig.
1) and perhaps Amphicoelia leidyi Hall (PI. 24, fig. 9) the
muscle has only one origin. In Cleconychia lamellosa (Hall)
usually only one anterior byssal retractor origin is discern-
ible (PI. 33, fig. 20), however, in a few specimens (PI. 33,
fig. 17) a second much smaller anterior byssal retractor
scar is present anterior to the larger scar. To date no an-
terior byssal retractor muscle scars have been observed in
any of the known Devonian ambonychiids.
The strength of development of the anterior byssal
retractor scars may give some indication as to the size of
the byssus. This is subject to such other considerations as
the size of the shell, the extent of the development of the
posterior byssal retractor muscle scars, and the like. In
Opisthoptera Meek the combination of characters of a small
byssal gape (Pl. 44, fig. 16), small bifid anterior byssal re-
tractor scars (PI. 43, fig. 11), and almost nonexistent pos-
terior byssal-pedal retractor scars (PI. 43, fig. 22) suggests
that the byssus was not a prominent structure. In Anomalo-
donta Miller the combination of large bifid anterior byssal
retractors (PI. 27, fig. 7), a large byssal gape (Pl. 27, fig.
6), and well-developed posterior byssal-pedal retractor scars
(Pl. 27, fig. 2) suggests that the byssus was composed of a
large tuft of fibers. On the other hand, the combination of
characters seen in Opisthoptera may indicate that once the
byssus was cemented in place the animal had little power
NortH AMERICAN AMBONYCHIIDAE: POJETA 149
of adjusting itself on its anchorage; whereas, the reverse
situation may have been true in Anomalodonta.
Above the posterior adductor muscle scar in such
genera as Anomalodonta Miller (Pl. 27, fig. 2) and Am-
bonychia Hall (Pl. 31, fig. 1) there is a muscle scar which
in the older literature was doubtfully referred to as a pedal
muscle scar. In typical dimyarian pelecypods a pedal re-
tractor is located in this position; however, in the byssate
Mytilacea the scar located above the posterior adductor
scar contains fibers of both the posterior pedal and_pos-
terior byssal retractor muscles. In ambonychiids this scar
was either made only by posterior byssal retractor muscle
fibers, or by both posterior byssal and posterior pedal re-
tractor muscles. In fossil forms there is no way to tell
whether this scar was made by both byssal and pedal re-
tractors or by byssal retractors alone. It seems best to con-
sider this scar as a combined byssal-pedal retractor scar, al-
though the foot was probably small in ambonychiids, if it
were present at all.
Ulrich (1892 and 1894) in his figures of Cleionychia
Ulrich shows a large posterior byssal-pedal retractor scar.
His specimens are not preserved well enough to warrant
this interpretation (PI. 35, fig. 16; Pl. 34, fig. 10).
4. Other muscle scars.— As mentioned above arcuate at-
tachment scars of the general surface of the mantle may be
present in some specimens of Cletonychia Ulrich (Pl. 33,
figs. 14-15). Gill suspensory muscle scars are not known in
ambonychiids, unless one of the arcuate rows of scars seen
in Cleionychia represents such muscles.
Several specimens are known which show various types
of irregular umbonal ridges in molds (PI. 22, figs. 15-17) .
Whether these ridges represent mantle attachments, irregu-
larities of the inner shell layer, or preservational peculiari-
ties is uncertain; probably examples of all three cases will
eventually be discerned. Only the finding of additional
specimens which give some idea as to the constancy of oc-
currence of these ridges can resolve the alternative ex-
planations.
Lastly, muscle traces of the ventral migration of the
posterior musculature have been found in a few well-pre-
served specimens (PI. 27, fig. 2; Pojeta, 1962, pl. 23, fig. 1) ;
however, these are not commonly preserved.
C. DENTITION
Above the specific level the dentition of ambony-
chiids is highly variable. There are edentulous forms such
as Ambonychinia Isberg, Anomalocoelia Isberg, and prob-
ably other genera. Some genera have only cardinal den-
tuition, for example Anomalodonta Miller (Pl. 28, fig. 1) ;
while cardinal and posterior lateral teeth occur in sey-
eral genera including Ambonychia Hall (Pojeta, 1962) ,
Gosseietia Barrois (Pl. 35, figs. 13, 15), and Stappersella
Maillieux. A few genera (e.g., Paramytilarca Isberg) are de-
scribed as having only posterior lateral teeth. In a majority
of forms, including 13 North American genera, the den-
tition is either unknown or only partially known.
In all known forms with cardinal teeth, the teeth are
located on a separate vertical lamella below the anterior
end of the duplivincular ligament (PI. 30, fig. 21); they
do not cross the ligamental area but are entirely below it
(Pl. 30, fig. 1). The cardinal teeth vary in number from one
Teeth
MORPHOLOGICAL
FEATURES
Anterior Lobe
Prosopon
Anterior Byssal
Retractor
Posterior Byssal-
Pedal Retractor
Posterior Lateral
Posterior Adductor
Anterior Adductor
Cardinal
Allonychia Wi) ee | ae | es
x
Anomalodonta - ne |e || = jf ey]
Anoptera
Ambonychia
Opisthoptera
Psilonychia
Palaeocardia
TABLE I: Distribution of major morphological features in North
American ambonychiid genera. A known feature is one that has been
observed in at least one species of the genus.
++. Indicates the structure or feature is known to occur in the
genus.
—. Indicates the structure or feature does not occur in the genus.
V. Indicates the structure or feature is poorly or doubtfully known
in the genus.
X. Indicates that it is not known whether the structure or feature
occurs in the genus; the known specimens of the genus not being well
preserved enough to determine the presence or absence of the struc-
ture.
150 PALAEONTOGRAPHICA AMERICANA (V, 36)
in Anomalodonta gigantea Miller (Pl. 27, fig. 1) to a
known maximum of five or six in Follmannia pseudalec-
tryonia (Frech).
Posterior lateral teeth are also always located beneath
the ligamental area. They may be attached directly to the
inner surface of the inner ostracum as in Ambonychia
radiata Hall (Pojeta, 1962, pl. 23, fig. 14) and 4d. alata
Meek (PI. 31, fig. 4); or they may be attached to what
is either a separate vertical lamella or a pronounced thick-
ening of the inner ostracum as in Mytilarca dalhousei
Clarke (PI. 38, fig. 14). These teeth are usually two or
three in number as in Ambonychia alata (Pl. 29, fig. 13),
Mytilarca chemungensis (Conrad) (PI. 38, fig. 4), and oth-
ers. However, Isberg (1954, pl. 13, fig. 5c) figured four pos-
terior lateral teeth in Mytilarca orsae Isberg, and this figure
represents the known maximum number for the family.
Where known, the vertical lamella which supports the
cardinal teeth is continued posteriorly below the ligamen-
tal area, although it is reduced in height (PI. 30, fig. 21).
In molds this vertical lamella often makes a pronounced
impression in the sediment and may be mistaken for a para-
vincular ligament (PI. 29, fig. 12). This phenomenon was
probably what led Kindle and Breger (1904) to erect the
genus Streptomytilus. Their description of the ligament in
that genus is as follows (p. 452):
. .. Hinge furnished with a posterior ligamental groove. There
is an internal linear platform or septum as in Mytilus edulis to which
the ligament is attached. This platform is present as a groove in the
cast. There are no teeth nor are there any ligamental striations .. .
The forms which they assigned to Streptomytilus are am-
bonychiid in other respects, and the description of the
ligament suggests that the vertical lamella below the liga-
mental grooves was being described rather than the liga-
mental area itself. The genus Streptomytilus is not recog-
nized herein and is further discussed below.
In most ambonychiids the dentition is weakly devel-
oped in the sense that the teeth are small structures, usually
being only slight “wrinkles” in the inner ostracum. Only
in Gosseletia Barrois (Pl. 35, fig. 18) and Stappersella
Maillieux are the teeth large well-developed prominences.
Numerous descriptive adjectives have been applied to
pelecypod dentition. In spite of this, none of the available
terms seems to be applicable to the highly variable denti-
tion of ambonychiids, with the exception of edentulous for
those which lack teeth. Pojeta (1962, p. 178) regarded the
dentition of the ambonychiid genus Ambonychia Hall as
of the dysodont type. Dysodont dentition has never been
adequately defined, and he regarded the dentition of Am-
bonychia as dysodont more from the fact that the genus
possesses such other dysodont features as fixation and aniso-
myarian musculature, than from any special characteristic
of the dentition itself. All ambonychiids can be placed in
the dysodont grouping; they all possess anisomyarian muscu-
lature, and all are fixed to the sea bottom.
SYSTEMATIC PALEOZOOLOGY
HIGHER TAXA
Phylum MOLLUSCA Cuvier, 1797
Class PELECYPODA Goldfuss, 1820
The molluscan class herein called Pelecypoda has long
been recognized as a separate zoological higher taxon. How-
ever, the nomenclature of this taxon has had a long and
varied history, and it is not yet agreed upon which of sey-
eral alternative names should be used. Because there are
no formal priority rules governing the naming of taxa as
high as those of class level, it becomes a matter of personal
prejudice as to which name an author prefers. My own pre-
judice in this matter favors the name Pelecypoda which was
first used by Goldfuss in 1820.
Beginning with 1758, numerous names have been pro-
posed to sum up the concept of this class. The most popu-
lar of these names (in alphabetical order) are: Acephala
Bivalvia Linné, Conchifera Lamarck, Lamelli-
branchiata (or its variant Lamellibranchia) de Blainville,
and Pelecypoda Goldtfuss. Several other names such as
Conchophora Gray and Dithyra Aristotle (reintroduced at
a later date) never came into wide use. By and large Ace-
Cuvier,
phala and Bivalvia passed out of general usage in the first
half of the nineteenth century, with most workers adopt-
ing either Lamellibranchiata or Conchifera. The latter
name was the most popular until about 1860-70. About this
time Conchifera was discarded, and in 1870 Stoliczka re-
introduced Pelecypoda; he was the first author in 50 years
to use Goldfuss’ name for the class.
With the reintroduction of Pelecypoda the names used
for the class gradually narrowed to Pelecypoda and Lamelli-
branchiata; some authors continued to use various of the
other names, however, they were in a minority. By about
the turn of the twentieth century the issue had resolved
itself in a curious way; North American authors espoused
Pelecypoda, while Europeans used Lamellibranchiata.
Haas (1929 and later) and Thiele (1934-35) disin-
tered the by-then-little-used name Bivalvia. In more recent
years several other authors have followed Haas and Thiele,
apparently with the hope of reconciling the geographic
usage of Pelecypoda and Lamellibranchiata. Cox (1960, p.
Nort AMERICAN AMBONYCHHDAE: POJETA 151
60) , in discussing the usage of these three class names, noted
the following:
I turn, now, to the molluscan class which I have been accus-
tomed to call the Lamellibranchia, but for which I readily adopt the
name Bivalvia, following Haas (1929-56) and Thiele (1934-5) in
their treatises on the group ...; at the same time I venture to ex-
press the hope that the third widely used alternative name, Pelecypoda,
will eventually be consigned to oblivion. . .
Various authors have noted the etymological inappro-
priateness of a name which means hatchet-footed for the
class as a whole. The general feeling being that in only a
relatively few species does the foot have anything like the
shape of a hatchet. This criticism can be leveled against
all of the names which have been applied to the group:
Bivalvia is inappropriate for rudistids in which one valve
is essentially reduced to an operculum covering the other;
plate or leaflike gills, stressed in the name Lamellibranchi-
ata, are not found in all pelecypods; while, Conchifera,
meaning shell bearer, is too inclusive.
It has been argued that if all of the names are etymo-
logically incorrect, at least Lamellibranchiata and Bivalvia
are “more correct” than Pelecypoda, and fit the great bulk
of forms assigned to the class, whereas, Pelecypoda does not.
In this connection, Stoliczka long ago noted (1870, p. 8):
I would recommend to those who object to the term Pelecypoda,
on the plea that the foot of these animals is not always hatchet-shaped,
the study of the various forms of hatchets and battle-axes of the
middle age.
Undoubtedly, one of the attractions of the name
Pelecypoda is that it fits in well with the other class names
which include the suffix --- poda (Scaphopoda, Gastropoda,
and Cephalopoda). This is a helpful memory aid, but it
must be acknowledged that the common root ending trend
for molluscan classes was long ago broken with the intro-
duction and general acceptance of such names as Amphi-
neura and Monoplacophora.
One of the criticisms of the reintroduction of the
name Bivalvia is that Linné’s original conceptual frame-
work, which was summed up by that name, included the
bivalved Brachiopoda. However, this objection could be
applied to most of the superfamilial taxa; the majority
of these were proposed a number of years ago and have
changed conceptually since they were first introduced.
A more serious objection to the use of the name Bi-
valyia is that other groups of animals besides pelecypods
possess two valves or something like two valves. I prefer
to use the designation bivalve as a general term for all
bivalved animals; as a term having no taxonomic implica-
tions, rather than as a part of the formal taxonomic hier-
archy.
Subclass PTERIOMORPHIA Buerlen, 1944
While at the class level almost all agree on the limits
of the taxon, and there are many names for one concept;
between this level and that of superfamily there are not
only many names but many concepts. The class has been
subdivided on the basis of almost every organ system,
on paleontological data, on neontological data, and so on;
however, the taxonomic schemes resulting from these dif-
ferent bases do not agree well with one another.
Newell’s 1965 classification of the Pelecypoda (Bi-
valvia) is used herein. His scheme is one of the most up-
to-date and forward looking systems available at the present
time.
Order PTERIOIDA Newell, 1965
Suborder PTERIINA Newell, 1965
Superfamily AMBONYCHIACEA Miller, 1877
(nom. transl. Newell, 1965)
The proper ordinal and superfamilial assignment of
the Ambonychiidae has long been problematic. Since its
proposal in 1877, the family has been placed in several
different superfamilies. Pelseneer (1906) included ambony-
chiids in the Pectinacea, while Dall (1900, 1913) placed
the group in the Pteriacea. Both the Pectinacea and the
Pteriacea are put in the order Pteroconchida by Cox, along
with the Pinnacea, Limacea, and Anomiacea. The Paleo-
zoic pteriaceans and pectinaceans are characterized by the
presence of a duplivincular ligament, and all of the ptero-
conchidians have an inequilateral shell, anisomyarian
musculature, and a byssus.
Moore, Lalicker, and Fischer (1952), following the
tentative suggestion of Newell (1942, p. 12), placed the
ambonychiids in the Mytilacea. Mytilaceans also are char-
acterized by a highly inequilateral shell, byssal attachment,
and anisomyarian musculature; however, throughout their
phylogenetic history, from the Recent mytilids to the Early
Paleozoic modiolopsids, they lack a duplivincular liga-
ment.
Dechaseaux (1952) included the Ambonychiidae in the
Actinodonta, which she treated as a suborder of the order
Taxodonta. She allied the Ambonychiidae to the Lyrodes-
matidae on a presumed relationship of the highly variable
dentition of ambonychiids to the peculiar dentition of
Lyrodesma Conrad and its allies. Actinodonts have a dis-
tinctive dentition, are dimyarian, and do not have the
highly reduced anterior end of ambonychiids. Thus, the
relationship between ambonychiids and actinodonts is
152 PALAKONTOGRAPHICA AMERICANA (V, 36)
not recognized herein. One of the reasons Dechaseaux may
have allied the actinodonts to the ambonychiids is that her
concept of the Ambonychiidae included the cytodontids;
these latter are herein regarded as forming a family separate
from the Ambonychiidae.
Pojeta (1962) assigned the ambonychiid genus Am-
bonychia Hall, and by inference the whole family, to the
Mytilacea. This assignment was based upon the general
body form and musculature of the Ambonychiidae; both of
these features are similar to various mytilaceans, especially
the Myalinidae. Moreover, the myalinids, which were
placed in the Mytilacea by Newell (1942), possess a well-
developed duplivincular ligament.
In addition to the Ambonychiidae Newell (1965) in-
cluded the Myalinidae and the Lunulacardiidae in the Am-
bonychiacea. His placement of the Ambonychiidae and
Myalinidae in a separate superfamily appears sound to the
author. These two families have rested rather uncomfort-
ably in the Mytilacea, primarily because of the presence of
the duplivincular ligament.
Family AMBONYCHIIDAE Miller, 1877
Diagnosis. — Equivalved, inequilateral pelecypods
which possess a byssus, duplivincular ligament, discon-
tinuous and integropalliate pallial line, anisomyarian mus-
culature, and variable dentition.
Definition. — Shell
prosogyral, terminal or nearly so; with or without an an-
equivalved, inequilateral; beaks
terior lobe and a posterior wing; byssal sinus prominent 01
not, byssal gape prominent or not; ostracum two-layered;
size small to large; umbonal ridge prominent only 1 the
dorsal half of the shell; prosopon variable, composed of
concentric growth lines only, or with costellae or costae
which may be simple or multiple.
Ligament of the duplivincular type, usually opistho-
detic, but it may be amphidetic; pallial line integropalliate
and discontinuous in attachment throughout most of its
length; adductor musculature heteromyarian or mono-
myarian; anterior and posterior byssal retractor muscles
present, the scar of the latter may represent the origin of
both posterior byssal and pedal retractor muscles; dentition
variable, it may include both cardinal and posterior lateral
elements, only one or the other of these, or it may be lack-
ing entirely.
Geologic
range. — Middle |= Ordovician
(Chazyan)
through Upper Devonian.
Discussion. —S, A. Miller was the first to suggest the
placement of Ambonychia s. l. and Anomalodonta Miller in
a separate family. In 1874b (p. 211) he noted the follow-
ing:
... McCoy and Woodward have placed the genus Ambonychia in
the family 4viculidae [Pteriidae], and I presume for the same rea-
sons they would put Megambonia [probably meaning <Allonychia
jamesi (Meek)] and Anomalodonta in that family. But these genera
seem to me to have a closer affinity with Myalina and other genera
belonging to the Mytilidac, than they have with the Aviculidae. One
cannot help being struck with the resemblance between the hinge line
of the Myalina subquadrata and that of the Anomalodonta gigantea.
It is quite probable, however, that these equivalve shells, with a large
byssus, belong to neither of these families, but to some other family .. .
However, Miller's actual erection of the family Am-
bonychiidae was somewhat inadvertent. In 1874 James Hall
sent Miller advance copies of volume five of the Paleon-
tology of New York. Hall (1883, p. 1) noted the follow-
ing:
... In 1874, several copies of the lithographed plates were bound
with interleaves, on which were written the names of species and ex-
planations of figures, as far as then determined. One of these copies
was sent to Mr. S. A. Miller, of Cincinnati, with the permission to
make such use of the material as he might think proper in the prepara-
tion of his catalogue of American Palaeozoic Fossils . . .
Hall’s advance copy of volume five apparently con-
tained several new familial names of pelecypods, for in
the preface to American Palaeozoic Fossils Miller wrote
(1877, p. 11):
.. The new family names in the Class Lamellibranchiata are
used by Prof. James Hall in the fifth volume of the Palaeontology of
New York...
However, the first pelecypod number of volume five of
the Paleontology of New York did not appear until 1883;
the rest of the pelecypod numbers of this volume appeared
in 1884 and 1885. Hall made no mention of the Ambony-
chiidae until 1884 (a and b), at which time he made no
claim to authorship of the family name. In 1883 Hall
placed the name Ambonychiidae at the top of each of the
plates containing figures of: Limoptera, Mytilarca, Gossele-
tia, and Byssopteria (pls. 26-33). Apparently he considered
these genera to belong to the family; however, he nowhere
mentioned the family name in the scanty text accompany-
ing the 1883 publication.
Because Miller was the first author to use the name in
print (1877, p. 180) and give a list of the genera which he
regarded as belonging to the family, he must receive credit
for the authorship of the family name and concept.
In 1869 and 1870 Hall and Whitfield published a pre-
liminary report of the genera and species to be included in
the pelecypod numbers of volume five of the Paleontoiogy
of New York, however, at this time they made no mention
of the higher taxa to be used in that volume.
NortH AMERICAN AMBONYCHIDAE: PoOJEerA I
Prior to Miller (1877) most authors had placed am-
bonychiids (principally the genus Ambonychia Hall) in the
Aviculidae (Pteriidae). In 1877 Miller assigned the follow-
ing six genera to the Ambonychiidae: Ambonychia Hall,
Anomalodonta Miller, Eopteria Billings, Euchasma Bill-
ings, Limoptera Hall and Whittield, and Mytilarca Hall
and Whitfield. Of these six genera only three are still re-
garded as ambonychiids: Ambonychia, Anomalodonta, and
Mytilarca, At the present time it is uncertain whethe1
Eopteria and Euchasma are pelecypods or bivalved crus-
taceans, and Limoptera is now placed in the Pterineidae.
In 1889 Miller recognized only four genera of ambony-
chiids: Ambonychia, Anomalodonta, Byssopteria Hall, and
Angellum Miller. Byssopteria is still regarded as an am-
bonychiid, however, Angellum is known only from one
poorly preserved and prepared specimen and is now ex-
cluded from the family. Bassler (1915) and Foerste (1916)
considered Angellium to be a cyrtodontid, and they are prob-
ably correct in their assignment.
Ulrich (1892-97) in his classical monographs on Minne-
sota and Ohio Ordovician pelecypods was one of the first
to give a formal definition of the family Ambonychiidae.
He recognized the following genera as belonging to the
family: Ambonychia Hall, Opisthoptera Meek, Anomalo-
donta Miller, Byssopteria Hall, Amphicoelia Hall, Mytil-
arca Hall and Whitfield, Palacocardia Hall, Plethomytilus
Hall, and the genera Cleionychia, Byssonychia, Anoptera,
Psilonychia, Eridonychia, Allonychia, and Ectenoptera all
proposed by Ulrich.
Since 1897 there has been no general work on North
American ambonychiids and only four new genera have
been erected: Streptomytilus Kindle and Breger, O pistho-
loba Ulvich in Hussey, Lophonychia Pohl, and Congerio-
morpha Stoyanow. A fifth new genus, Maryonychia, is erect-
ed herein.
In Europe Maillieux (1920 and 1937) placed Gosseletia
Barrois, Stappersella Maillieux, and Follmannia Drever-
mann in the family; while Isberg (1934) described six new
genera of Ambonychiidae from the Dalarna region of
Sweden: Ambonychinia, Ambonychiopsis, Elasmodophora,
Praeanomalodonta, Anomalocoelia, and Paramytilarca.
Vokes (1951-54) in his mimeographed Preliminary Clas-
sification of the Genera of the Pelecypoda gave the most re-
cent literature compilation of the genera placed in the
AAmbonychiidae. Eliminating corrections as to familial
placement made by Vokes, as well as synonyms, his com-
pilation placed the following additional genera in the Am-
bonychiidae: Enkebergia (Wedekind MS) in Schindewollf,
1924; Modiella Hall, 1883; Mytilops Hall, 1883; Pyanomya
Miller, 1881; Pterochaenia Clarke, 1904; Duvorecia Ruzicka,
1949; and Joachymia Ruzicka, 1949. The latter two genera
were originally described as subgenera of Pterochaenia.
Of these seven genera Modiella, Mytilops, and Pyano-
mya are mytiloid in their general body form, are not known
to have a duplivincular ligament, and are not herein re-
garded as belonging to the Ambonychiidae; they probably
belong in the Modiolopsidae. Enkebergia was not figured in
the original description, however, because of its opistho-
gyral beaks I do not consider the genus to belong to the
Ambonychiidae.
Joachymia is pteriiform in its general outline, and
appears to be a pterioid. It is not known whether the
genus is inequivalved or not; Ruzicka placed it in the
Pteriidae. Most Early Paleozoic pterioids are placed in the
Pterineidae, and Joachymia may belong to that family.
Dvorecia has a shell outline reminiscent of Allonychia
flanaganensis Foerste. Ruzicka (1949, p. 117) noted that
right valves of the type species, Dvorecia contempta (Bar-
rande), are a little less convex than left valves; he con-
sidered these right valves to be “pelomorphically de-
formed.” His treatment of Duorecia as a pterioid may be
correct; however, ambonychiid affinities cannot yet be ruled
out entirely.
Pterochaenia has usually been associated with Lunula-
cardium Minster in the Lunulicardiidae, although Ruzicka
(1949) placed Pterochaenia in the Pteriidae. The genus is
apparently equivalved and has a large byssal gape. How-
ever, the general shell shape is not ambonychiid and noth-
ing is known of the ligamental structures. At least for the
present there seems to be no reason to place this genus in
the Ambonychiidae.
Khalfin (1940) and Eberzin (1960) placed the Siberian
Devonian genus Myalinopterella Khalfin, 1940, in the
Ambonychiidae. Khalfin’s figures leave doubt as to the
proper familial placement of this genus; it may or may
not be an ambonychiid.
Kayser (1901) described the ribbed genus Nathorstella
from Spitzbergen as being almost equivalved; the genus is
ambonychiid in its shell shape and may belong to the Am-
bonychiidae. Lastly, Maillieux (1937) described Demanetia
from the Early Devonian of the Ardennes area. Frech’s
(Enech)) Vase pls 5;
figs. I-la) are of a ribbed almost equivalved form, and
figures of Demanetia lodanensis
Demanetia may be an ambonychiid.
Of the numerous genera which have been placed in the
Ambonychiidae since 1877, the following 16 are herein
considered to be the known North American representa-
tives of the family:
154 PALAEONTOGRAPHICA AMERICANA (V, 36)
Genus Author Year Age
Allonychia Ulrich 1894 Ordovician
Ambonychia Hall 1847 Ordovician
Ambonychiopsis Isberg 1934 Ordovician
1mphicoelia Hall 1865 Silurian
Anomalodonta Miller 1874 Ordovician
Anoptera Ulrich 1893 (1895) Ordovician
Byssopteria Hall 1883 Devonian
Cleionychia Ulrich 1892 Ordovician
Congeriomorpha Stoyanow 1948 Devonian
Gosseletia Barrois 1882 Devonian
Lophonychia Pohl 1929 Devonian
Maryonychia Pojeta new genus Ordovician ;
M ytilarca Hall & Whitfield 1869 Silurian-Devonian
O pisthoptera Meek 1872 Ordovician
Palaeocardia Hall 1865 Silurian
Psilonychia Ulrich 1893 (1895) Ordovician
Several of the above genera are poorly known morpho-
logically, and future work may change the number pres-
ently recognized.
The generic names Byssonychia Ulrich, Eridonychia
Ulrich, Ectenoptera Ulrich, Plethomytilus Hall, O pistho-
loba Ulrich in Hussey, and Streptomytilus Kindle and
Breger apply to North American ambonychiids but are
not recognized for various reasons described under the
genera concerned.
Seven genera, which are herein considered to be am-
bonychiids are not known from North America:
Genus Author Year Age
Ambonychinia Isberg 1934 Ordovician
Anomatlococlia Isberg 1934 Ordovician
Elasmodophora Isberg 1934 Ordovician
Follmannia Drevermann 1907 Devonian
Paramytilarca Isberg 1934 Ordovician
Pracanomalodonta Isberg 1934 Ordovician
Stappersella Maillieux 1920 Devonian
In addition to these 23 genera, the non-North American
genera Myalinopterella Khalfin, Dvorecia Ruzicka, Nathor-
stella Kayser, and Demanetia Maillieux may belong to the
family.
The above listing of the seven non-North American
ambonychiid genera is taken from Isberg (1934) and Mail-
lieux (1920 and 1937). I have had no European material
at my disposal and have had to depend entirely upon the
literature for knowledge of these forms. The genera listed
by Maillieux appear to be distinct; however, Isbere’s genera
seem to overlap among themselves and with North Ameri-
can forms, and restudy of his materials will probably show
that his proposed taxonomy will have to be revised.
Isberg’s (1934) materials were from the Leptaena lime-
stone of the Dalarna area of Sweden. There has been some
uncertainty as to the correct age assignment of this forma-
tion; whether it is entirely Ordovician or both Ordovician
and Silurian. According to the Lexique Stratigraphique
International (Magnusson, 1958) and Thorslund (1960) ,
the Leptacna limestone is now divided into two formations:
the lower Kullsberg limestone of Middle Ordovician age
and the upper Boda limestone of Upper Ordovician age.
European ambonychiids have been reported from Bel-
gium, Czechoslovakia, Estonia, Germany, Ireland, Norway,
Russia, Spain, Scotland, and Sweden. Curiously, Barrande
(1881) reported no ambonychiids from Central Europe,
although several genera had been described by 1881. Some
of Barrande’s figures resemble ambonychiids; however, his
original materials must be restudied before many of the
forms named by him can be placed in the proper families.
The oldest known North American members of the
family occur in rocks of Chazyan age (Early Middle Ordo-
vician) in New York State and adjacent parts of Canada.
These forms were placed in the genera Cleionychia Ulrich
and Ambonychia Hall [Ambonychiopsis Isberg] by Ray-
mond (1916). His two species of Cleionychia seem to be
properly assigned, however, the single species of Ambony-
chia [Ambonychiopsis] can only be doubtfully placed in
that genus.
Mohawkian forms (Middle and Late Middle Ordo-
vician) from New York State, Wisconsin, Minnesota, On-
tario, and elsewhere are placed in Cleionychia, Ambony-
chiopsis, and Ambonychia. As far as can be determined
from type material and the literature all three genera are
found in Mohawkian rocks.
In the problematic Cynthiana rocks of northern Ken-
tucky and southwestern Ohio, only Allonychia Ulrich and
Ambonychia Hall have been definitely identified. The
single species of Cleionychia (Pl. 32, figs. 8-9) reported
from these rocks is too poorly preserved to determine its
generic assignment. Cynthiana rocks are either Late Middle
Ordovician or Early Late Ordovician in age.
From rocks of Cincinnatian age (Late Ordovician) in
North America the following genera have been identified:
Allonychia, Anomalodonta Miller, Anoptera Ulrich, Am-
bonychia, Maryonychia, n. g., Opisthoptera Meek, and
Psilonychia Ulrich.
In the Cincinnatian section at Cincinnati, Ohio, rocks
of Eden age are only known to contain representatives of
the genus Ambonychia; in the Maysville Stage rocks the fol-
lowing three genera have been identified — Allonychia, Am-
bonychia, and Psilonychia; while in Richmond Stage rocks
Anoptera, Anomalodonta, Ambonychia, Maryonychia, and
Opisthoptera are known.
North American Silurian forms have been placed in
three genera: Amphicoclia Hall, Mytilarca Hall and Whit-
field, and Palaeocardia Hall. The latter genus is known
only from Niagaran rocks (Middle Silurian) ; Amphicoelia
|
NortH AMERICAN AMBONYCHHDAE: POJETA
_has been reported from Niagaran and Cayugan rocks (Mid-
dle and Late Silurian) ; while Mytilarca has been reported
from all three Silurian series— Medinan (Early Silurian) ,
| Niagaran, and Cayugan.
Among Devonian genera Byssopteria Hall is known to
occur only in the Upper Devonian (Chemung) rocks of
Pennsylvania; Congeriomorpha Stoyanow has been report-
ed only from Chemung rocks in Arizona; Gosseletia Barrois
is geographically more widely distributed, occurring in the
Middle Devonian of New York, Michigan, and Ohio; while
Lophonychia Pohl is reported only from the Middle Devy-
onian (Cazenovian) Lake Church formation of Wisconsin.
Devonian forms which have been assigned to the genus
Mytilarca Hall and Whitfield have been reported from all
Devonian series and most Devonian stages. (See ‘Table II
for a synoptic listing of the stratigraphic occurrence of
North American genera.)
On the other continents, reports of ambonychiids are
not common, and the generic and even familial assign-
ments often must be considered as tentative. Ambonychia ?
kiitsingensis Grabau, 1926 from the Silurian of Yunnan
Province, China, may be an ambonychiid; it does not be-
long to the genus Ambonychia. Cleionychia oviformis Ko-
bayashi, 1934 from the Middle Ordovician of Korea is al-
most certainly an ambonychiid, but only one valve is
known. Allonychia? brevirostris Leith, 1938 from the Mid-
dle Ordovician of Venezuela is probably not an ambony-
chiid. Byssopteria? sp. Reed, 1904 from the Devonian of
South Africa is too poorly preserved to tell whether or not
it belongs to the Ambonychiidae. According to Daily (1956,
p. 130) the Australian Early Cambrian species Ambonychia
macroptera ‘Vate, 1892, is a brachiopod. The form fig-
ured under the name cf. Mytilarca sp. by Sherrard (1960)
from the Silurian rocks of New South Wales does not ap-
pear to be an ambonychiid; the specimen figured is not
well preserved. Termier and Termier (1950) listed and
figured Follmannia sp. as occurring in the Middle Devonian
rocks (Eifélien) of Moracco. Their description is brief,
and their figure is only a line drawing, thus, the proper
placement of this form is uncertain. At the United States
yational Museum (PI. 35, figs. 5-7) there are several speci-
mens of ambonychiids from Devonian rocks at Kuahsin-
shan, Kiitsing, Yunnan, and Liu Koping, China; these speci-
mens are herein regarded as belonging to the genus
Follmannia Drevermann.
A number of ambonychiid genera have been reported
from both sides of the Atlantic including: Ambonychia
Hall, Amphicoelia Hall, Ambonychiopsis Isberg, Byssop-
teria Hall, Cleionychia Ulrich, Gosseletia Barrois, Mytil-
arca Hall and Whitfield, and Psilonychia Ulrich. Several
ID
of these identifications must be considered as tentative;
the problems raised by each of them are discussed under
the genus concerned.
Ambonychiids which have been reported from Missis-
sippian rocks are not herein considered to be members of
the family. As far as known all of the Mississippian forms
have been placed in the genus Mytilarca, and they are fur-
ther discussed under that genus.
There is a small group of post-Osagian (Early Middle
Mississippian) forms which have been described as being
equivalved or almost equivalved, and are included in the
family Myalinidae. These forms are excellent morphological
connecting links between the ambonychiids and myalinids,
although they do not necessarily occur in the proper tem-
poral sequence. Ranging from Middle Mississippian to
Early Permian time is the genus Septimyalina Newell; in
describing this genus Newell noted the following (1942, p.
64) :
... both valves smooth, or rugose, in the latter instance the sur-
face of the left valve being markedly more rugose than that of the
right; inequivalve, the right valve being slightly flatter and smaller
around the ventral periphery than the left...
Selenimyalina Newell (Middle and Late
vanian) was described by Newell as (1942, p. 63) :
Pennsyl-
. nearly equivalve, the right valve being almost imperceptibly
less convex than the left, apparently not discordant .
Newell then went on to compare Selenimyalina to My-
tilarca Hall and Whitfield and suggested that the former
may be derived from the latter:
... Selenimyalina is closely comparable with the Devonian M ytil-
arca Hall [and Whitfield]. Although similar forms are not known
from the Mississippian rocks, it seems probable that the Late Paleo-
zoic genus was derived from the Devonian form. The shell microstruc-
ture and musculature is not known in Mytilarca, but there seems to be
very close agreement between the two genera in form and characters
of the ligament area.
The Permian myalinid Licbea Waagen is described
as subequivalved, with the right valve almost imper-
ceptibly less convex than the left; however, the prosopon
of the two valves differs. The Permian myalinid genera
Atomodesma Beyrich and Maitaia Marwick, were both orig-
inally described as being equivalved. Waterhouse (1958)
considered these generic names to be synonyms, with A tomo-
desma having priority. Waterhouse (1958 and 1963) de-
scribed Atomodesma as biconvex, but did not note whether
the genus was equivalved or inequivalved in his generic
descriptions. In 1958 (p. 171) he described A. trechmanni
(Marwick) as being equivalved; while in 1963 (p. 708) he
noted that A. woodi Waterhouse is “probably equivalve,”
156 PALAEONTOGRAPHICA AMERICANA (V, 36)
and that A. trabeculum Waterhouse (p. 713) and Atomo-
desma sp. B (p. 715) “are apparently equivalve.” Also in
1963 (p. 171) Waterhouse noted that some specimens of 4.
trechmanni might be inequivalved, although he suggest-
ed that this might be due to distortion. Thus, there is
some question as to whether or not Atomodesma is equi-
valved. As far as can be determined from figured speci-
mens there is no indication of any difference in the proso-
pon of the two valves of Atomodesma.
Because the only readily descernible distinction be-
tween ambonychiids and myalinids is the equality or in-
equality of the valves, this characteristic is taxonomically
important. On a morphological basis Atomodesma should
be placed in the Ambonychiidae if it can definitely be
shown to be equivalved; this would extend the range of the
family from the Late Devonian to the Permian, with no
known Carboniferous intermediates. At the present time
there is nothing to suggest that Atomodesma may have sec-
ondarily returned to an equivalved condition from pleuro-
thetic ancestors.
Whether Atomodesma is equivalved or not, the Late
Paleozoic subequivalved myalinids form excellent morpho-
logical intermediaries between the Early Paleozoic equi-
valved ambonychuds and the Late Paleozoic distinctly 1n-
equivalved myalinids. The existence of almost equivalved
myalinids and the great morphological similarities in shell
shape, ligamental type, and musculature suggest an evolu-
tionary relationship between the Ambonychiidae and the
Myalinidae. This aspect will be discussed further in the
section dealing with phylogeny.
GENERIC DESCRIPTIONS
No attempt is made herein to revise all of the species
of North American ambonychiids. Well over 100. specific
names have been proposed for the North American forms
alone, and few of these species have been re-examined in the
light of modern taxonomic procedures. However, each gen-
eric discussion includes a listing of the species which have
been assigned to that genus, and in many cases comments
are made as to the author's thoughts on the validity of
various of the specific names. Herein, only the species oc-
curring in the Upper Ordovician rocks of the Tristate Area
of Ohio, Indiana, and Kentucky are redescribed.
A serious attempt has been made to frame mutually
exclusive and useful generic descriptions and diagnoses.
However, as will be apparent from the generic descriptions,
some of the genera are still broadly defined, and the finding
of better preserved materials may result in further sub-
division at the generic level. For example, the primary
taxobases used to distinguish the Siluro-Devonian genus
Mytilarca Hall and Whitfield are the presence of concentric
prosopon and the lack of an anterior lobe. The internal
features of virtually all of the species assigned to the genus
are poorly known, and future study may show that the genus
as now recognized is composed of several generic level taxa.
On the other hand, several generic names have been
proposed which are so close conceptually to previously
named genera that they are not herein recognized. In this
connection, Opistholoba Ulrich in Hussey does not differ
significantly from Opisthoptera Meek; Eridonychia Ulrich
is regarded as a synonym of Ambonychia Hall; and the
taxobases upon which Streptomytilus Kindle and Breger
and Plethomytilus Hall were founded do not differ appre-
ciably from those used to recognize Mytilarca Hall and
Whitfield.
Late Ordovician North American ambonychiids have
been split the most at the generic level, and by and large
these forms are known from the best preserved materials.
In Upper Ordovician rocks probably only the finding of
entirely new morphological forms, rather than increased
knowledge of already named genera, will alter the number
of forms presently recognized.
The name Palaecocardia Hall presents a unique prob-
lem, in that its conceptual base cannot be ascertained.
The only specimen of the type species of the genus is poorly
preserved and prepared (PI. 45, figs. 7-10), and the name
will probably have to be limited to this single specimen,
‘There is even some question as to whether or not Palaco-
cardia is an ambonychiid.
GENERIC DIFFERENTIA
By and large generic differentiation in the Ambony-
chiidae is not based upon single characteristics but usually
upon a combination of several criteria. ‘Taxobases which
have been used to distinguish genera within the family in-
clude:
1. Type of prosopon.
2. Presence or absence of a well-developed byssal gape.
3. Dentition.
4. Various linear dimension ratios (such as, the ratio of the
length to the height).
5. Development of an anteroventral salient.
6. Presence or absence of an anterior lobe.
7. Presence or absence of a posterior wing.
8. Terminal or nonterminal beaks.
9. Position of the posterior musculature (i.¢., subcentral or in the
posterodorsal portion of the shell).
10. Size.
11. Others.
Genus ALLONYCHIA Ulrich, 1894
Plates 19-21
1859. [Non] Megambonia Hall, Nat. Hist. New York, Geol. Sur. New
York, Palaeont., vol. 3, part 1, p. 273.
NortH AMERICAN AMBONYCHIIDAE: POJETA 157
1872. Megambonia Meek, Acad. Nat. Sci. Philadelphia, Proc. for
L871, part 35 Pp. S21.
1873. Megambonia Meek, Geol. Sur. Ohio, Rep., vol. 1, part 2, Palae-
ont., p. 136. [This is a reprinting of Meek, 1872, above. |
1894. Allonychia Ulrich, Lower Sil. Lamellibranchiata of Minnesota,
from Final Rep., Geol. and Nat. Hist. Sur. Minnesota, vol. 3,
p. 498. [Pubished under separate cover prior to the entire vol.
3s
1893 Gass Allonychia Ulrich, [partim], Geol. Sur. Ohio, Rep., vol.
7, p. 640.
1897. Alleny hia Ulrich, Geol. and Nat. Hist. Sur. Minnesota, Final
Rep., vol. 3, part 2, Paleont., p. 498. [This is a reprinting of the
1894 paper above.]
1908. Allonychia Ulrich, Cumings, Dept. Geol. and Nat. Resources
Indiana, 32d Ann. Rep., p. 978.
1909. Allonychia Ulrich, Grabau and Shimer, North American Index
Fossils, vol. 1, p. 432.
1931. Allonychia Ulrich, MeFarlan, jm Jillson, Kentucky Geol. Sur.,
Paleont. of Kentucky, p. 112.
Type species.—Megambonia jamesi Meek, 1872, (p.
$21), by original designation of Ulrich, 1894 (p. 498), as
Allonychia jamesi (Meek) .
Diagnosis. — Costate Ambonychiidae with an anterior
lobe.
Description. — Shell equivalved, inequilateral, with a
prominent anterior lobe; beaks prosogyral, not terminal;
obliquity prosocline; prosopon where known of concentric
growth varices and simple radial costae; shell substance
completely unknown; byssal sinus presumed to be below
the anterior lobe, no discernible byssal gape; no posterior
wing; known size range medium to large.
Ligamental areas with duplivincular grooves and
ridges but poorly known; ligamental space wide; anterior
adductor scar unknown, posterior adductor scar known only
from remnants which are located posterior to the center
of the valve; where known only a single anterior byssal re-
tractor scar is present; dentition unknown.
Distribution. — Only two species are herein recog-
nized as belonging to this genus: Allonychia jamesi (Meek)
occurs in rocks of Maysville age (Middle Late Ordovician)
in the Tristate Area of Ohio, Indiana, and Kentucky; while
Allonychia flanaganensis Foerste is from the Cynthiana for-
mation of central Kentucky, in the general vicinity of Win-
chester, Paris, and Lexington, Kentucky.
The species reported by Leith (1938) from the Middle
Ordovician of Venezuela as Allonychia? brevirostris does
not seem to belong to this genus; it has subcentral beaks,
lacks an anterior lobe, and only one valve of the species is
known.
Remarks and comparisons. — Among North American
forms Allonychia is the only genus which combines radial
costae and an anterior lobe; Gosseletia Bariois and Con-
geriomorpha Stoyanow possess concentric prosopon. only,
while Ambonychiopsis Isberg has costellae.
SPECIES DESCRIPTIONS
All species assigned to Allonychia are known only from
the Ordovician rocks of the Tristate Area of Ohio, Indiana,
and Kentucky.
Allonychia jamesi (Meek), 1872
Plate 19, figures 1-10
1872. Megambonia jamesi Meek, Acad. Nat. Sci. Philadelphia, Proc.
for 1871, part 3, p. 321, no fig.
1873. Megambonia jamest Meek, Geol. Sur. Ohio, Rep., vol. 1, part 2,
Palaeont., p. 136, pl. 12, figs. 9a-b. [Except for the figures this
is a reprinting of the 1872 description above. |
1874. Megambonia jamesi Meek, Miller, Cincinnati Quart. Jour. Sci.,
vol. 1, pp. 13, 225, no fig. [Paraphrasing of Meek’s 1872 de-
scription. |
1889. Ambonychia jamesi Meek, Miller, North American Geol. and
Palaeont., p. 460, no fig.
1893 (1895). Allonychia jamesi Meek, Ulrich, Geol. Sur. Ohio, Rep.,
vol. 7, p. 641, pl. 48, fig. 7.
1908. Allonychia jamesi (Meek), Cumings, Dept. Geol. and Nat. Re-
sources Indiana, 32d Ann. Rep., p. 986, pl. 43, fig. 2. [Same fig-
ure as Ulrich, 1893 (1895).]
1909. Allonychia jamest (Meek), Grabau and Shimer, North Ameri-
can Index Fossils, vol. 1, p. 432, no fig.
Diagnosis. —Allonychia having 50-60 costae and angle
gamma of 100 degrees or more.
Description. — Shell ovate and obliquely elongate; pos-
sessing 50-60 costae; angle gamma, 100-110 degrees; liga-
mental space wide; greatest convexity of a single valve, up
to 25 mm.; size medium to large, up to 90 mm. in diagonal
dimension; length and height subequal.
Duplivincular grooves and ridges present; musculature
unknown, except for remnants of the posterior adductor,
which are located slightly behind the center of a valve,
but not in the posterodorsal part of the shell; dentition
completely unknown.
Synonymic discussion.—This_ species was originally
placed in Megambonia Hall; Ulrich in 1894 chose the
species as the type of his genus Allonychia considering it
to be a distinct form because of the presence of an an-
terior lobe.
Types and materials. — Meek’s original type suite of
the species consists of only the holotype (W.M. No. 556).
This specimen is distorted and weathered, but it does
show the anterior lobe well (PI. 19, figs. 1-4) and also pos-
sesses remnants of the costation.
The dimensions of the holotype are as follows: length,
57 mm.; height, 57 mim.; convexity of a single valve, 19
mm.; diagonal dimension, 60 mm.; and number of cos-
tae uncertain. The costae are best preserved on the left
valve where about 55 can be counted, however, this does
not cover the entire shell surface and probably 50 or more
were originally present. The anteriormost portion of the
anterior lobe does not show a byssal gape as indicated by
158 PALAEONTOGRAPHICA AMERICANA (V, 36)
Meek (1873) ;
edge of the anterior lobe but no sign of a byssal gape.
Ulrich’s 1893 (1895) hypotype (U.S.N.M. No. 46079)
while not distorted is not well preserved; it shows remnants
there is a slight ridge weathered into one
of the posterior muscle scars (Pl. 19, fig. 5). Ulrich’s fig-
ure of this specimen (pl. 48, fig. 7) is highly interpretive;
he showed the entire pallial line and all of the posterior
muscle scars. The dimensions of this specimen are: length,
75 mm.; height, 76 mm.; convexity, 25 mm.; diagonal
dimension, 86 mm.; number of costae uncertain, only about
30 preserved, but probably 50 or more were originally
present.
In addition to type materials, the author had at his
disposal three other specimens of this species. None of
these show any internal features except remnants of the
duplivincular ligament; all have 40 plus costae and one
has 46 plus costae, it is on this basis that the species is re-
garded as having between 50 and 60 costae.
Distribution. — As far as known this species is limited
to the Corryville member of the McMillan formation (Up-
Ohio,
and Kentucky. All of my specimens are from the Corryville
per Maysville) in the Tristate Area of Indiana,
member, as is Ulrich’s 1893 (1895) hypotype. The exact
stratigraphic position of Meek’s holotype is unknown,
Meek (1872,
“Cincinnati group... .
p. 322) gave the stratigraphic position as:
at Cincinnati, Ohio, about 350 feet
above low-water mark of the Ohio
Remarks and comparisons. — Both Meek and Ulrich
treated this species as though a byssal gape were present on
the anterior face of the anterior lobe. As mentioned above
Meek’s specimen does not show this feature. However, in
Ulrich’s hypotype (Pl. 19, fig. 6) and in two of the new
specimens at my disposal (PI. 19, figs. 7-8) there is some
suggestion of a byssal gape in the anterior face of the an-
terior lobe. Unfortunately, none of the materials upon
which these observations are based are well preserved, and
two of the specimens are definitely distorted. It is diffi-
cult to imagine a byssal gape in this position, as the ani-
mal would then be “teeter-tottering” on the anterior lobe.
If what appears to be an anterior lobe in this species can
be shown to be a protuberant byssal gape, then the species
possesses a structure which is unique in ambonychiids, and
A. jamesi might have to be generically separated from 4d.
flanaganensis. The issue can only be decided when new
and better preserved materials are found. It is possible that
an apparent byssal gape would be developed in an an-
terior lobe in which the anterior face had been weathered
down.
In none of the materials of A. james: presently avail-
able can all of the costae be counted; the number 50-60
is my estimate as to how many were originally present.
Ulrich (1893 (1895), p. 641) noted: “In a series of eight
specimens of A. james: the number of ribs varies between
55 and 68, and in only one of these is it less than 60.”
However, Ulrich figured none of these specimens; in the
single hypotype which he did figure about 30 costae can
be counted, the costae being only partially preserved.
Allonychia jamesi differs from A. flanaganensis in
having a larger angle gamma. Additionally, the length and
height of A. jamesi are usually subequal, while in A. flan-
aganensis the length is appreciably greater than the height. —
Allonychia flanaganensis Foerste, 1914
Plate 19, figure 11; Plate 20, figures 1-10; Plate 21, figures 1-4
1912. Allonychia flanaganenesis Foerste, [nomen nudum], Sci. Labs.
Denison Univ., Bull., vol. 17, p. 30.
1914. Allonychia flanaganensis Foerste, Cincinnati Soc. Nat.
Jour., vol. 21, No. 4, p. 134, pl. 2, figs. 1A-B.
1931. Allonychia flanaganensis Foerste, McFarlan, im Jillson, Ken-
tucky Geol. Sur., Paleont. of Kentucky, p. 113, pl. 7, fig. 1.
Hist.,
Diagnosis. — Allonychia with a long cardinal margin
and an angle gamma of 85-95 degrees.
Description. — Shell elongate in an anterior-posterior
direction, such that the length is greater than the height,
the shape gives a strongly prosocline aspect to the species;
angle gamma, 85-95 degrees; prosopon of concentric growth
varices, and perhaps flat costae; umbones projecting well
above the cardinal margin (5 mm. or more in undistorted
materials) ; size large, up to 100 mm. or more in diagonal
dimension; greatest convexity of a single valve, up to 30
mm.; presumed position of byssal sinus is below the anterior
lobe; no discernible byssal gape; ligamental areas diverge
widely leaving a ligamental space of up to 10 mm. in non-
shelled specimens.
Dentition and the nature of the ligamental insertions
unknown; pallial line and musculature unknown except for
the scar of a single anterior byssal retractor muscle.
Synonymic discussion. — Foerste’s original reference to
this species (1912) occurs in the description of a strati-
graphic section of Cynthiana rocks. Here he merely listed
the species name and gave a series of linear measurements
for the species. ‘The author feels that this is not a sufficient
enough description to enable a subsequent worker to iden-
tify the species and, thus, considers the original use of the
name to be a nomen nudum, Subsequently, in 1914, Foerste
adequately described and ‘figured the species.
Types and materials. — The types of the species consist
of two syntypes (U.S.N.M. Nos. 78722, 142806); of these,
the specimen figured by Foerste (1914) on plate 2, figure
1A, and illustrated herein on Plate 20, figures 1, 2, is chosen
as the lectotype of the species; the other specimen (PI. 19,
NortH AMERICAN AMBONYCHIIDAE: POJETA 159
fig. 11) is regarded as a paralectotype. The measurements of
the lectotype are as follows: length, 91 mm.; height, 80 mm.;
maximum convexity, 25 mm.; and diagonal dimension, 106
mm. Measurements of the paralectotype are: length, 78
mm.; height, 64 mm.; maximum conyexity, 23 mm.; and
diagonal dimension, 89 mm.
In addition to the type materials, the author had lit-
erally hundreds of specimens at his disposal; these were
collected in and around Winchester, Kentucky. Unfortu-
nately, specimens of this species are usually poorly pre-
served single valves. Although the species occurs in super-
abundance at some localities, little insight can be gained
from most of the specimens. Even for statistical studies the
great majority of specimens are useless, because they are
incomplete single valves on which no accurate measurements
can be made. Of the hundreds of specimens collected six
of the best preserved are figured herein, and these illustrate
little beyond the general shape of the shell.
Distribution. — The only known occurrence of this
species is in the lower Cynthiana formation — the so-called
Millersburg phase —in the general vicinity of Paris, Win-
chester, and Lexington, Kentucky.
Remarks and comparisons. — The incredible abundance
of this species at some localities suggests that it may have
lived in the same gregarious fashion as some modern my-
tilaceans. For example, on the open beaches of the south
shore of Long Island Mytilus edulis Linné can be found
completely covering rock jetties, and the animals are often
piled up four or five deep. Despite the jetties, the wave
action along these shores is vigorous, and the shells which
are washed up on shore are almost always disarticulated.
The occurrence of large numbers of single valved specimens
of pelecypods in the fossil record is usually taken to mean
that the region was one of vigorous wave action; such was
almost certainly the case for Allonychia flanaganensis. Cor-
roborating this is the fact that 4. flanaganensis is often
covered with small circular encrusting ectoproct colonies;
ramose ectoprocts are almost never found in the enclosing
sediment. Occasional bivalved specimens of other pelecy-
pods are found associated with A. flanaganensis, but these
are few in number; I know of only one specimen of A. flana-
ganensis (Pl. 20, fig. 10) in which the valves are articulated.
The prosopon of this species is poorly known. Both
Foerste (1914) and McFarlan (1931) described flat low
costae separated by shallow and narrow interspaces which
are easily overlooked. Such a condition is seen on Plate
20, figure 7 herein. This specimen is completely over-
grown by an encrusting ectoproct, which grows in small
circular colonies that coalesce over the entire surface of the
pelecypod; a common feature often seen on specimens of
this species. The flat costae seen in this specimen, as well
as the apparent growth varices, are actually features in
the surface of the ectoproct. The encrustation may reflect
the original prosopon which was below it, but this needs
confirmation from unencrusted materials; to date none of
the unencrusted materials show any prosoponal features.
It is not uncommon to find two ridges on the posterior
umbonal slope of Allonychia flanaganensis molds (PI. 20,
fig. 8); these are present only where the original shell of
the animal was thickest and presumably represent muscle
traces of the posterior musculature. If so, then the species
possessed both a posterior adductor and a posterior byssal-
pedal retractor.
Specimens of A. flanaganensis definitely show that
there was no discernible byssal gape in the anterior face
of the anterior lobe (PI. 20, fig. 3). There is a single an-
terior byssal retractor scar in each valve and, thus, a byssus
was present; presumably it existed between the valves below
the anterior lobe, as is the case in the Devonian lobed
genus Congeriomorpha Stoyanow; the latter shows a prom-
inent byssal gape immediately below the anterior lobe.
Allonychia ovata Ulrich, 1893 (1895)
A. subrotunda Ulrich, 1893 (1895)
Plate 21, figures 5-15
In addition to the species discussed above, Ulrich
(1893 (1895), pp. 641-642) named two other species of
Allonychia: A. ovata and A. subrotunda.
The material upon which A. ovata is based (Pl. 21,
figs. 5-9) is not well preserved and does not show the promi-
nent anterior lobe seen an A. jamesi and A. flanaganensis.
The holotype of A. ovata (Pl. 21, figs. 5-7; U.S.N.M. No.
46080) has a general shell shape similar to that of Ambony-
chia acutirostris (Ulrich), 1893 (1895) (Pojeta, 1962, pl.
24, fig. 9) ; according to the museum labels the holotypes of
both species are from the Fairmount member of the Fair-
view formation (Lower Maysville) at Covington, Kentucky.
There is a slight anterior projection of the shell beneath
the beaks in the holotype of Allonychia ovata; however, this
does not protrude forward of the rest of the shell as is typi-
cal in Allonychia, rather it is similar to the shell projection
seen in Ambonychia acutirostris which defines the lower
limit of the byssal sinus. Ulrich’s illustration (1893 (1895) ,
pl. 48, fig. 5) of the ligamental and dental structures of the
holotype of Allonychia ovata is highly interpretive; the
specimen shows nothing of the ligamental grooves and
ridges or of the dentition (PI. 21, fig. 7) .
A paratype of d. ovata (U.S.N.M. No. 142808) shows
160 PALAEONTOGRAPHICA AMERICANA (V, 36)
an anterodorsal prominence (PI. 21, fig. 9). However, this
specimen is more poorly preserved than the holotype, and
it is uncertain whether this prominence represents a struc-
ture which was originally a part of the shell.
Herein, Allonychia ovata Ulrich is regarded as a prob-
able synonym of Ambonychia acutirostris (Ulrich) . The
holotypes of the two species compare favorably, and the
holotype of Allonychia ovata does not have the character-
istic anterior lobe of Allonychia.
Bassler (1919, p. 284) reported A. ovata from the
“Martinsburg Shale (Fairview division)” of southeastern
Pennsylvania. Unfortunately he refigured Ulrich’s 1893
(1895) illustrations of the “species,” and it is uncertain
with what species he was concerned.
The holotype of Allonychia swbrotunda (U.S.N.M. No.
46081) is a distorted external cast (PI. 21, figs. 12-15). On
the right valve 42 plus costae can be counted, and the speci-
men probably had about 50 costae on each valve. Because
of the preservation it is difficult to tell whether or not an
anterior lobe was present. The anterodorsal face of the shell
has been broken, and the broken edges produce a_byssal
gapelike structure (Pl. 21, fig. 15); this broken area may
have originally been an anterior lobe. Below the broken
area there is an anterocentral projection (PI. 21, fig. 12) ;
whether or not this anterocentral salient is due to the skew-
ing of the valves over one another is uncertain.
A paratype of A. subrotunda (U.S.N.M. No. 142809)
has 55 plus costae (Pl. 21, figs. 10-11), it too may or may
not have had an anterior lobe. Until new materials of this
form are found it cannot be determined whether it belongs
to Allonychia or to some other genus.
Genus AMBONYCHIOPSIS Isberg, 1934
Plates 21-24
1847. Ambonychia Hall, [partim], Nat. Hist. New York, Palaeont.,
vol. 1, pp. 163, 292, and 315.
1850. Posidonomya Bronn [partim], d’Orbigny, Prodrome de Paléon-
tologie, vol. 1, p. 13.
1854. [?] Ambonychia Hall, McCoy, Description of the British
Palaeozoic Fossils, p. 264.
1855. Posidonomya Bronn [partim], Emmons, American Geology, vol.
I pantyZ ap. L7G:
1859. [Non] Ambonychia Hall, New York State Cab. Nat. Hist., 12th
Ann. Rep., pp. 8 and 110.
1859. [Non] Ambonychia Hall, Nat. Hist. New York, Geol. Sur. New
York, Palaeont., vol. 3, part 1, pp. 269 and 523. [This is a re-
printing of the material published in the 12th Ann. Rep. above. |
1871. [Non] Ambonichia |Ambonychia| Hall, Stoliczka, Geol. Sur.
India, Palaeontologia Indica, Mem., vol. 3, ser. 6, p. 387.
1871. Ambonychia Hall [partim], Woodward, A Manual of the Mol-
lusca, 2d ed., p. 417.
1875. [Non] Ambonichia [Ambonychia| [Hall], Worthen and Meek,
Geol. Sur. Illinois, vol. 6, p. 495.
1877. Ambonychia Hall [partim], Miller, The American Palaeozoic
Fossils, p. 181.
1881. [Non] Ambonychia Hall, Zittel, Handbuch der Palaeontologie,
Abt.ol:,, Band!2, p: 35.
1883. [Non] Ambonychia [Hall], Miller, Supplement to the American
Palaeozoic Fossils, p. 309.
1886. Ambonychia Hall [partim], Fischer, Manuel de Conchyliologie,
p. 962.
1889. Ambonychia Hall [partim], Miller, North American Geol. and
Palaeont., p. 460.
1894. Ambonychia Hall, Ulrich, Lower Sil. Lamellibranchiata of Min-
nesota, from Final Rep., Geol. and Nat. Hist. Sur. Minnesota,
vol. 3, p. 489. [Published under separate cover prior to the
entire vol. 3.]
1897. Ambonychia Hall, Ulrich, Geol. and Nat. Hist. Sur. Minnesota,
Final Rep., vol. 3, part 2, Paleont., p. +89. [This is a reprinting
of the 1894 paper above. |
1909. Ambonychia Hall, Grabau and Shimer, North American Index
Fossils, vol. 1, p. 429.
1910. [2]. dmbonychia Hall, Hind, Roy. Soc. Edinburgh, Trans., vol.
47, part 3, p. 488.
1926. [Non] Ambonychia Hall, Grabau, Geol. Sur. China, Palaeon-
tologia Sinica, ser. B, vol. 3, fase. 2, p. 46.
1934. Ambonychinia Isberg, [partim], Studien Uber Lamellibranchia-
ten des Leptaenakalkes in Dalarna, p. 29.
1934. Ambonychiopsis Isberg, Studien Uber Lamellibranchiaten des
Leptaenakalkes in Dalarna, p. 82.
1944. Ambonychia Hall, Shimer and Shrock, Index Fossils of North
America, p. 385.
1952. Ambonychia Hall, Moore, Lalicker, and Fischer, Invertebrate
Fossils, p. 414.
1952. [?] Ambonychia Hall, Dechaseaux, im Piveteau, Traité de
Paléontologie, tome 2, p. 266.
1952. [?] Ambonychinia [Isberg] [partim], Reed, Roy. Irish Acad.,
Proc., vol. 55, sec. B, No. 3, p. 73.
1956. Ambonychia Hall, Wilson, Canada Dept. Mines and Tech. Surs.,
Geol. Sur. Canada, Bull. 28, p. 57.
1960. [?] Ambonychinia Isberg, Soot-Ryen, H. anl Soot-Ryen, T.,
Norsk Geologisk Tidsskrift, vol. 40, part 2, p. 102.
1960. [?]. dmbonychia Hall, Soot-Ryen, H. and Soot-Ryen, T. Norsk
Geologisk Tidsskrift, vol. 40, part 2, p. 103.
Type species—Ambonychiopsis osmundsbergensis — Is-
berg, 1934 (p. 82), by original designation.
Diagnosis. — Costellate Ambonychiidae with an anterior
lobe.
Description. — Shell equivalved, inequilateral, with an
anterior lobe; beaks nonterminal, prosogyral; obliquity
prosocline; prosopon of fine simple costellae crossed by
concentric growth varices and often also by concentric
undulations; byssal sinus presumed to be below the anterior
lobe; discernible byssal gape absent; shell material un-
known; size small to large.
Ligamental and dental structures unknown; muscula-
ture incompletely known, there is a single anterior byssal
retractor, and the posterior adductor muscle scar has been
observed.
Synonymic discussion. —'The generic name Ambony-
chiopsis Isberg is herein hesitantly applied to costellate,
Middle Ordovician, North American species which were
formerly placed in Ambonychia Hall. Because of a recently
discovered nomenclatural difficulty, the generic name Am-
bonychia Hall must now be applied to those species which
were formerly included under the name Byssonychia UI-
rich, Ulrich (1894-97) considered Ambonychia bellistriata
Hall, 1847 to be the type species of Ambonychia; Miller
NortH AMERICAN AMBONYCHIIDAE: POJETA 161
(1889) also considered A. bellistriata to be the type species
of Ambonychia, and all authors subsequent to Ulrich and
Miller have followed this practice. However, Stoliczka
(1870, p. XXI; 1871, p. 387) had previously chosen Aim-
bonychia radiata Hall, 1847 as the type species of Ambony-
chia. Stoliczka’s type species designation being the earlier,
the conceptual base for Ambonychia must be dA. radiata
and not A. bellistriata.
Ulrich (1894, p. 498) chose A. radiata as the type
species of the genus Byssonychia; because Byssonychia has
the same type species as Ambonychia it becomes a junior
objective synonym of Ambonychia and must be discarded
(International Code of Zoological Nomenclature, Art. 61b,
p. 61). The various species formerly placed in Byssonychia
must now be included under the name Ambonychia; this
leaves those species which were placed in Ambonychia on
the conceptual base of 4. bellistriata without a generic
name. It is herein proposed that these species be tentatively
placed in Isberg’s Late Ordovician Scandinavian genus
Ambonychiopsis.
Ambonychiopsis includes anteriorly lobed costellate
species, however, more knowledge of both the North Ameri-
can and Scandinavian forms placed in Ambonychiopsis is
needed before it can be conclusively shown that they are
congeneric. For the time being placement of the North
American, Middle Ordovician, costellate species in Am-
bonychiopsis will create fewer difficulties than would the
proposal of a new name for the American forms.
Isberg’s genus Ambonychinia is not available as a re-
placement name for Ambonychia based upon A. bellistriata.
The type species of Ambonychinia, A. undulata Isberg,
lacks costellae; A. undulata is an anteriorly lobed concen-
trically marked form and differs significantly morphologi-
cally from Ambonychiopsis and A. bellistriata. However, Is-
berg included several costellate species in Ambonychinia; it
is herein recommended that these costellate forms be trans-
ferred to Ambonychiopsis.
The relationships of the concentrically marked species
of Ambonychinia to each other and to other concentrically
marked ambonyhiid genera are uncertain. Probably those
forms, such as 4. undulata, which are edentulous and have
an anterior lobe can remain in a separate genus bearing
Isberg’s name Ambonychinia. ‘Those forms lacking an an-
terior lobe would be better placed in the genus Cleronychia
Ulrich. There are several species of Ambonychinia which
are too poorly known to be segregated as suggested above
2. I would like to thank Dr. N. D. Newell for bringing Stoliczka’s
type designation for Ambonychia to my attention.
and for the time being these will have to remain in Am-
bonychinia.
Isbere defined Ambonychiopsis as having cardinal
teeth, while Ambonychinia was supposed to lack these.
However, his figures of Ambonychiopsis show no cardinal
teeth. Ulrich (1894) defined Ambonychia based on A.
bellistriata as having two small cardinal teeth and no lat-
eral teeth. In the Zittel-Eastman Textbook of Paleontology
Ulrich supphed Dall with the information on Early Paleo-
zoic pelecypods, and here the genus is defined as edentu-
lous. Because Isberg did not illustrate the dentition of Am-
bonychiopsis and because Ulrich described it both as hay-
ing and as lacking cardinal teeth, the dentition of Ambony-
chiopsis is herein regarded as unknown.
To summarize, the generic name Ambonychia must
rest upon A. radiata as a conceptual base rather than upon
A. bellistriata; Stoliczka (1871) chose the former species as
the type species of the genus prior to Miller’s (1889) and
Ulrich’s (1894) use of A. bellistriata for the type species of
Ambonychia. The two species differ significantly morpho-
logically and provide different conceptual bases for the
name Ambonychia. Because Ulrich chose A. radiata as the
type species of Byssonychia Ulrich, this generic name be-
comes a junior objective synonym of Ambonychia Hall
(both genera having the same type species) and is invalid.
It is tentatively suggested that Ambonychiopsis Isberg be
used for those American species formerly placed in Am-
bonychia based upon A. bellistriata, as both the American
and Scandinavian forms are anteriorly lobed costellate am-
bonychiids of the A. bellistriata type. Additionally, it is
suggested that the costellate species of Ambonychinia Isberg
be transferred to Ambonychiopsis and that the name Am-
bonychinia be limited to anteriorly lobed, concentrically
marked, edentulous ambonychiids.
It is difficult and hazardous to revise genera from
afar when only retouched figures are available, however,
some attempt must be made to reconcile the taxonomy of
North American and Scandinavian forms. With this latter
thought in mind it is hoped that the above suggestions
will make the names Ambonychia, Ambonychinia, and
Ambonychiopsis useful taxonomic designations, each hav-
ing a different conceptual base.
The problem of the conceptual bases of the above
generic names has from time to time led to confusion in
the literature. Thus, Reed (1952, p. 74), while describing
Irish Ordovician species, recommended that all forms with
concentric prosopon be placed in Ambonychinia and those
with costellate prosopon in Ambonychia; apparently he
based this upon the observation that the type species of
162 PALAEONTOGRAPHICA AMERICANA (V, 36)
Ambonychinia possesses only concentric prosopon. Reed
was followed in this arrangement by Soot-Ryen and. Soot-
Ryen (1960) in their descriptions of Norwegian species.
The use of Ambonychia for Ordovician costellate species
is no longer possible because of the redefinition of the
concept behind that name caused by the discovery of
Stoliczka’s designation of A. radiata as the type species of
Ambonychia.
By the same token Ambonychinia cannot be used for
all concentrically marked Ordovician species for Ulrich
(1892) had previously used Cleionychia for American
Middle Ordovician forms having only concentric prosopon.
In addition, Ulrich (1893 (1895)) proposed the names
Anoptera and Psilonychia for American Late Ordovician
species which are concentrically marked. Isberg (1954) used
six generic names besides Ambonychinia and Psilonychia
for concentrically marked ambonychiids from the Leptaena
limestone (Anomalococlia Isberg, Amphicoelia Hall, Elas-
modophora Isberg, Mytilarca Hall and Whitfield, Paramy-
tilarca Isberg, and Pracanomalodonta Isberg) .
Thus, at least 10 generic names have been used for
Ordovician concentrically marked ambonychiids. “These
genera are not readily separable and their conceptual bases
are uncertain for all of them are morphologically incom-
pletely known. Psilonychia is separable as the only genus
with a readily discernible byssal gape; Elasmodophora,
Mytilarca, and Paramytilarca are dentate; Ambonychinia,
Amphicoclia, Anomalocoelia, and Praeanomalodonta are
supposed to be edentulous; while the dentition of Cleiony-
chia and Anoptera is unknown.
Amphicoelia as known from Silurian rocks is always
ribbed and it is doubtful that this name can be used for
concentrically marked Ordovician forms. Whether the name
Mytilarca can be used for Ordovician forms will depend
upon the elucidation of the morphology of the Devonian
species for which the name was proposed. Paramytilarca and
Ambonychinia are anteriorly lobed genera; Paramytilarca is
dentate and Ambonychinia is edentulous. ‘The relationships
of the names Elasmodophora, Anomalocoelia, and Praeano-
malodonta to Cleionychia and Anoptera are vague. ‘The
North American genera bear the older names, but are
incompletely known morphologically; only when the entire
hard part morphology of the American genera is known can
a solution to the dilemma be offered. In the meantime it
is probably best to use the names Cleionychia and Anoptera
whenever possible in preference to Isberg’s names.
Pojeta (1962) monographed the Late Ordovician repre-
sentatives of what he called the genus Byssonychia. These
forms are now placed in Ambonychia because of the re-
definition of that name on the basis of A. radiata.
Types and materials.— The foregoing description of
Ambonychiopsis is based upon Isberg’s (1934) description,
Hall’s and Ulvich’s type materials of Ambonychia based on
A. bellistriata, and several new specimens from the collec-
tions of the United States National Museum. The type ma-
terials are herein photographed for the first time, and many
of the specimens differ significantly from the interpretive
figures of the original authors.
Distribution. — In North America Ambonychiopsis, as
herein construed, is limited to rocks of Middle Ordovician
age in the states of Illinois, Minnesota, and New York, and
the provinces of southeastern Canada. One species, A.?
curvata (Raymond), has been reported from rocks of
Chazyan age, but as noted by that author (1916, p. 335)
this species may be improperly assigned for it is not known
to possess costellate. There is one Blackriveran species, A.
planistriata (Hall), and the rest of the species are ‘Tren-
tonian in age. Outside of North America the genus is known
to occur in the Middle and Upper Ordovician rocks of
Scandinavia.
NORTH AMERICAN SPECIES LISTING AND REMARKS
Bassler (1915, pp. 29-31) listed 41 North American
Ordovician and Silurian species which at one time or an-
other had been assigned to Ambonychia. Based on A. belli-
striata [Ambonychiopsis] he recognized nine of these
species as still belonging to the genus; this number is herein
reduced to a maximum of six, and perhaps should be re-
duced further as noted below.
Ambonychiopsis affinis (Ulrich), 1894
Plate 22, figures 8-12
This species is based upon two syntypes, one of which
is an incomplete specimen (U.S.N.M. No. 46083) and the
other of which is poorly preserved (M.G.S. No, 8342). Of
these specimens the one figured herein on Plate 22, figures
10-12. (U.S.N.M. No. 46083) is chosen as the lectotype of
the species. This is the better preserved of the original
syntypes and was more extensively figured by Ulrich.
The exact age assignment of Ulrich’s materials of A.
affinis is uncertain; Bassler (1915, p. 29) gave the age as
Trentonian. However, the museum label accompanying
the lectotype has the age as Blackriveran, while the museum
label accompanying the paralectotype has the age as “Gal-
ena’ which is Trentonian.
The lectotype of the species shows a small but prom-
inent anterior lobe and the space which Ulrich regarded
NortH AMERICAN AMBONYCHIDAE: POJETA 163
as a “clavicular impression” (PI. 22, fig. 12). In addition,
it has traces of costellae and concentric undulations (PI.
Dex ree IU).
Ulrich’s distinctions between this species and 4. plani-
striata (Hall) are as follows (1894, p. 492) :
... the beaks and umbones [of 4. affinis] are a little less tumid
and the convexity of the shell correspondingly less. The shell is also
a trifle more erect and rounder, the hinge line slightly shorter and
the posterocardinal margin more rounded. Finally, the concentric
undulations are much more obscure, while the radiating striae are
coarser, there being only eight in 5 mm. to twelve in the same space
for that species [4. planistriata].
Neither the primary types:of A. planistriata (PI. 23,
figs. 7-8) nor of A. affinis (Pl. 22, figs. 8-12) are well pre-
served, and with the exception of the coarseness of the
costellae, it is doubtful if the species criteria suggested by
Ulrich could be objectively applied by all authors. The
costellae are barely discernible on the lectotype of A. affinis
and not distinguishable at all on the paralectotype. In the
lectotype of A. planistriata there are 1! to 2 costellae per
mm. around the edge of the shell. Probably A. affinis
(Ulrich) should be regarded as a junior synonym of 4.
planistriata (Hall) .
Wilson (1956) applied the name 4. affinis to a speci-
men from the Middle Ordovician Ottawa formation of
eastern Canada. This specimen is not well preserved and
as figured shows no costellae; however, in her description
Wilson (1956, p. 57) noted that costellae are present.
Ambonychiopsis amygdalina (Hall), 1847
Plate 22, figures 2-7
Hall’s holotype (A.M. No. 745/1) and Ulrich’s 1894
hypotype (U.S.N.M. No. 46085) of this species are fig-
ured herein; neither of these specimens shows costellae or
an anterior lobe, although the holotype shows the so-called
clavicular space (Pl. 22, fig. 5).
The dimensions of the holotype (PI. 22, figs. 2-5) are:
length, 59 mm.; height, 46 mm.; thickness of a single
valve, 14 mm.; and diagonal dimension, 67 mm. This speci-
men is similar in outline to specimens of A. orbicularis
(Emmons) (PI. 22, figs. 13-18) and is probably a poorly
preserved specimen of this species. The holotype of 4.
amygdalina and the known specimens of 4. orbicularis are
from rocks of ‘Trentonian age in New York State. Ulrich’s
1894 hypotype (PI. 22, figs. 6-7) is from rocks of Tren-
tonian age in Minnesota, however, it is poorly preserved,
and could belong to any one of several Middle Ordovician
ambonychiid species.
Foerste (1920) listed this species as occurring in the
Kimmswick limestone of Illinois (Trentonian) but gave
no details of the occurrence. Wilson’s 1956 specimens. as-
signed to A. amygdalina are too poorly preserved to iden-
tify.
Ambonychiopsis bellistriata (Hall), 1847
Plate 21, figures 16-22; Plate 22, figure 1; Plate 24, figures 1,2
Hall’s original type suite of A. bellistriata was com-
posed of two syntypes (1847, pl. 36, figs. da-d) ; of these
at least the specimen used by Hall for his figure 4a was
examined by Ulrich (1894, p. 492) at the American Mu-
seum of Natural History (A.M. No. 717/2). Unfortunately
this specimen can no longer be located. ‘The second of
Hall’s syntypes (1847, pl. 36, figs. 4b-d) is herein figured
on Plate 21, figures 16-19. This specimen is now housed at
the New York State Museum in Albany (N.Y.S.M. No.
2232) ; it was obtained by the Museum from Ward’s Natural
Science Establishment which purchased the Moore Collec-
tion around the year 1900. In the original description of
A. bellistriata, Hall (1847, p. 164) noted that the speci-
mens were from the “Cabinet of Mr. Moore of Trenton
Falls [New York];” in addition, the specimen compares
favorably with Hall’s original figures and there is no doubt
that it was the specimen used by Hall for his figures 4b-d.
This specimen is herein chosen as the lectotype of the
species; the missing syntype is regarded as a paralectotype.
Although the valves of the lectotype have slid over
each other, the following measurements were taken: length,
30 mm.; height, 32 mm.; thickness of a single valve, 10 mm.;
and diagonal dimension, 39.5 mm. Around the edge of the
shell there are about 30 costellae in 10 mm., giving an aver-
age of about three costellae per mm., and the shell is crossed
by a series of rather obscure concentric undulations. In the
anterodorsal portion of the left valve, where it is partially
covered over by the right valve, there appears to be a
remnant of an anterior lobe (PI. 21, fig. 18). The speci-
men is from the Trentonian rocks of New York.
At the United States National Museum there are two
plaster casts of the lectotype of A. bellistriata (U.S.N.M. No.
4827). On the label identifying these molds there is a
handwritten comment by E. O. Ulrich that the specimen
herein regarded as the lectotype of A. bellistriata (Hall,
1847, pl. 36, figs. 4b-d) is a different species from the para-
lectotype (Hall, 1847, pl. 36, fig. 4a). Ulrich goes on to
write that he had accepted the specimen illustrated by Hall
in figure da as the “type” of A. bellistriata. However, in
none of Ulrich’s ambonychiid works seen by me does he
make mention of choosing a lectotype for A. bellistriata.
In 1894 (p. 492) Ulrich made mention of having examined
the types of 4. beilistriata, but he included both of Hall’s
164 PALAEONTOGRAPHICA AMERICANA (V, 36)
original specimens and did not choose one or the other as
a lectotype.
Ulrich’s 1894 hypotype of A. bellistriata (U.S.N.M.
No. 46084) is a smaller specimen than the lectotype with
the following measurements: length, 27.5 mm.; height,
27 plus mm.; thickness, 9 mm.; and diagonal dimension,
35 plus mm. In this specimen (PI. 21, figs. 20-22) there
are about 244 to 3 costellae per mm. around the edge of
the shell. No anterior lobe or “clavicular impression” is
present; what Ulrich figured as such structures (Pl. 21, figs.
21-22) seems to be the result of preparation. Ulrich’s speci-
men is from the Trentonian rocks of Minnesota.
In addition to the above materials, several new speci-
mens of this species are figured herein; these latter materials
show that the species possesses a small anterior lobe.
Ambonychiopsis? curvata (Raymond), 1905
This species is from Chazyan roc ks of New York State.
It was questionably assigned to Ambonychia by Raymond
pending the finding of costellae. In 1916 Raymond again
discussed this form, however, his figures show neither cos-
tellae nor an anterior lobe.
Ambonychiopsis orbicularis (Emmons), 1842
Plate 22, figures 13-18; Plate 23, figures 1, 2 and 12-15
This species was placed in Ambonychia by Hall in
1847, at which time he figured two hypotypes. The speci-
men figured by Hall on plate 56, figure 5a (N.Y.S.M. No.
2233) is herein figured on Plate 22, figures 16-18. This speci-
men preserves the posterior adductor muscle scar (PI. 22,
fig. 18) and perhaps a single anterior byssal retractor scar
(Pl. 22, fig. 16). Its measurements are: length, 49 mm.;
height, 47 mm.; thickness, 14 mm.; and diagonal dimen-
sion, 55 mm.
The specimen figured by Hall on plate 36, figures 5b-d
is herein figured on Plate 22, figures 13-15 (A.M. No.
716/1); this hypotype shows a prominent anterior lobe
and the so-called clavicular space. Its measurements are:
length, 52 mm.; height, 56 mm.; thickness, 15 mm.; and
diagonal dimension, 62 mm. Hall figured the costellate
prosopon of this specimen, however, the small costellate
area of shell material which Hall indicated as being present
in his figure is no longer on the specimen.
Also at the American Museum there is an unfigured
Hall hypotype of this species (A.M. No. 716/1) ; the speci-
men is somewhat distorted in that the umbo has been
pushed medially. However, the anterior lobe still shows,
as does the “‘clavicular impression.”
In addition to the above hypotypes a series of new
specimens of A. orbicularis is figured herein. These clearly
show the costellate prosopon (PI. 23, fig. 13), anterior lobe
(Pl. 23, fig. 13), posterior adductor muscle scar (PI. 23,
fig. 12), and anterior byssal retractor scar (Pl. 23, fig. 14).
The new materials make 4. orbicularis the morphologically
best known species presently assigned to Ambonychiopsis.
Emmons named this species Pterinea orbicularis in the
report on the Second District in the Geology of New York
(1842, p. 395). His description and figure are exceedingly
generalized, and his original material could not be located.
Because the type materials of Early Paleozoic pelecypods
are stored in many museums, and because the revision of
the original descriptions has only begun in recent years,
no neotype is chosen for Ambonychiopsis orbicularis (Em-
mons) .
As far as known this species is limited to rocks of
Trentonian age in New York State. Wilson’s 1956. speci-
men from the Ottawa formation of Canada is not well pre-
served, and whether or not it belongs to this species cannot
be determined. As mentioned above A. amygdalina (Hall)
may be a junior synonym of A. orbicularis (Emmons) .
Ambonychiopsis planistriata (Hall), 1861
Plate 23, figures 3-9
Hall’s original proposal of this species included no
figures and it was not until 1895 that Whitfield figured two
of Hall’s three syntypes. Of the three syntypes only one
shows costellae; this specimen is herein figured on Plate
23, figure 8 (A.M. No. 922/1) and is chosen as the lecto-
type of the species (Whitfield, pl. 7, fig. 5). It has the
following dimensions: length, 45 mm.; height, 40 mm.;
thickness, 12 mm.; and diagonal dimension, 55 mm. There
are about 114-2 costellae per mm. around the edge of the
shell and the specimen shows vague concentric undulations.
The other two specimens are regarded as paralectotypes.
Ulrich’s 1894 hypotypic suite consists of two specimens,
only one of which was figured by him. The specimen shown
here on Plate 25, figures 3-6 was figured by Ulrich on his
plate 35, figures 3-4 (U.S.N.M. No. 46086). Its measure-
ments are: length, 37 mm.; height, 31 mm.; thickness of a
single valve, 15 mm.; and diagonal dimension, 45 mm. The
specimen appears to be compressed dorsoventrally, and the
right upper umbo and beak have been reconstructed with
dental wax by the original describer; it has 2 to 2% cos-
tellae per mm., and a series of prominent concentric un-
dulations.
Ulrich’s unfigured hypotype (M.G.S. No. 8327) is
shown herein on Plate 23, figure 9; it is not well preserved
NortH AMERICAN AMBONYCHIIDAE: POJETA 165
but does show concentric undulations and about 2% to 3
costellae per mm.
For Ulrich the major distinguishing feature of this
species was prominent concentric undulations. However,
this feature occurs in other forms and cannot by itself con-
stitute the main specific taxobasis.
Hall reported A. planistriata as occurring in the ‘Tren-
tonian rocks of Wisconsin, the museum label accompanying
Ulrich’s figured hypotype places it in the Blackriveran of
Wisconsin, and Bassler (1915, p. 31) listed the species as
occurring in the Blackriveran of Illinois, Minnesota, and
Wisconsin.
In addition to the above species, Bassler (1915) listed
the species Ambonychia illinoisensis Worthen, A. septen-
trionalis Whiteaves, and A. undulatus (Whitfield) as be-
longing to Ambonychia based on A. bellistriata. None of
these species has an anterior lobe, and they are not herein
regarded as belonging to Ambonychiopsis; however, their
proper generic assignments are uncertain.
Ambonychia illinoisensis is Late Ordovician in age,
ambonychiid in shape, and has costae. It may belong to one
of the Late Ordovician costate genera, however, I have not
seen the original material of the species and cannot assign
it to a particular genus.
Both A. septentrionalis and A. undulatus (Pl. 23, figs.
10-11) are from rocks of Middle Silurian age, and both have
concentric undulations. The former species is described as
having minute radiating lines (costellae?), whereas, the
latter species lacks radial prosopon. A. septentrionalis may
belong to the Silurian genus Amphicoelia Hall which is a
costellate form. However, as figured by Whiteaves Ambony-
chia septentrionalis lacks the prominent anteroventral sal-
ient of Amphicoelia.
Whitfield’s 1882 specimen of Ambonychia undulatus
is figured herein (Pl. 23, figs. 10-11); it is not so well
preserved as indicated by him and shows an almost subcen-
tral upper umbo. If it is an ambonychiid, it may also be-
long to Amphicoclia, however, new materials of the species
are necessary before its proper assignment can be deter-
mined.
In summary, the genus Ambonychiopsis contains a
maximum of six (perhaps fewer) North American species
which occur in the Middle Ordovician rocks of a rela-
tively restricted geographic area. Most of the species placed
in the genus are based upon external characteristics only,
and new materials are badly needed to establish the correct
taxonomic position of both the American and Scandinavian
forms.
Genus AMPHICOELIA Hall, 1865
Plates 24, 25
1865. Amphicoelia Hall, Advance Printing for the 18th Report on the
New York State Cabinet, p. 35.
1866. Amphicoelia [Hall], Winchell and Marcy, Boston Soc. Nat.
Hist., Mem., vol. 1, p. 108.
1866. Amphicoelia Hall, Meek and Worthen, Geol. Sur. Illinois, vol.
2, p. 339.
1867. Amphicoelia Hall, Meek, American Jour. Sci. and Arts, vol. 94,
p- 173.
1868. Amphicoelia Hall, New York State Cab. Nat. Hist., 20th Ann.
Rep., Ist ed., pp. 339 and 387. [Reprinting of Hall, 1865 above;
title page dated 1867.]
1868. Amphicoelia Hall, Meek and Worthen, Geol. Sur. Illinois, vol,
2 im AS%,
1870. Amphicoelia Hall, New York State Cab. Nat. Hist., 20th Ann.
Rep., revised ed., pp. 386 and 431. [Essentially a reprinting of
Hall, 1865 above; title page dated 1868.]
1871. Amphicoelia Hall, Geol. Sur. State of Wisconsin, 1859-1863,
Palaeont., part third, p. 42. [Essentially a reprinting of Hall,
1865 above. |
1889. Amphicoelia Hall, Miller, North American Geol. and Palaeont.,
p. 461.
1934. [?] Amphicoelia Hall, Isberg, Studien Uber Lamellibranchiaten
des Leptaenakalkes in Dalarna, p. 101.
Type species.—Amphicoclia leidyi Hall, 1865 (p. 35),
by monotypy.
Diagnosis. — Ribbed Ambonychiidae with a prominent
anteroventral salient and an obtuse angle gamma.
Description. — Shell equivalved, inequilateral, lacking
an anterior lobe, with a prominent anteroventral salient
forming an obtuse angle gamma; beaks prosogyral, terminal;
obliquity prosocline; cardinal margin long; prosopon where
known of costellae or costae, growth varices, and some-
times concentric undulations; shell poorly known; no dis-
cernible byssal gape; byssal sinus prominent; size medium
to large.
Ligamental area with duplivincular grooves and
ridges; pallial line unknown: posterior adductor muscle
scar located in posterodorsal region of the shell, anterior
adductor muscle scar unknown; small single anterior byssal
retractor scar behind each beak; dentition unknown.
Synonymic discussion.—The generic name Amphicoelia
poses an intricate nomenclatural problem concerning the
date when it was introduced into the paleozoological litera-
ture. In at least four different publications, spanning the
years 1865-1871, Hall introduced Amphicoelia as a new
generic name.
Bassler (1915, p. 32) listed the origin of the name
Amphicoela as: “Hall, 20th Rep. New York State Cab.
Nat. Hist., 1868 (extras, 1865) p. 339.” Bassler’s “extras”
are a special 48 page publication issued by Hall in 1864-65
dealing with Silurian echinoderms, arthropods, and mol-
lusks, In which Hall named several new specific and gen-
eric taxa. This publication is entitled: Account of Some
166 PALAEONTOGRAPHICA AMERICANA (V, 36)
New or Little Known Species of Fossils from Rocks of the
Age of the Niagara Group.
The number of copies of the “extras” issued by Hall is
uncertain. At the Geology Library of the United States
National Museum, among Meek’s reprints, there is a copy
of an “extra” which Hall sent to Theodore Gill. The first
page of this separate is headed: “Printed in Advance, for the
18th Report on the New-York State Cabinet.” At the top
of this page is the date December 26, 1864; inscribed on
the page in both ink and pencil is the handwritten nota-
tion: “Recd. March 7, 1865.” At the bottom of pages 1
and 9 the date December, 1864 appears; while at the bot-
tom of pages 17, 25, 33, 41, and 48 the date January, 1865
appears.
Hall (1868, pp. 382-383) in an expanded version of
the Account of Some New or Little Known . . . wrote:
The first forty-eight pages of this paper were published in De-
cember 1864 and January 1865 ... On the 27th Dec. 1864, I wrote
to Prof. Winchell, sending him at the same time the first sixteen
pages of my paper on Niagara fossils ... Under date of Dec. 31st,
1864, Prof. Winchell replied to my letter of the 27th . . . early in
January 1865... all the matter published by me was in the hands of
the printer...
The above quotations are taken from a series of com-
ments Hall wrote concerning a disagreement he was having
with Winchell and Marcy, who in 1866 had published a
paper on the same Niagaran fauna which Hall had de-
scribed in the Advance Printing for the 18th Report. ‘The
comments show that the Advance Printing appeared in two
parts: the first 16 pages in December, 1864, and the next
32 pages in January, 1865. Hall (1868, p. 552) noted that
he had originally intended to publish a more extensive
version of the 1865 paper, but that the printing of the paper
was suspended after 48 pages in January, 1865. ‘These com-
ments by Hall and the dates which appear at the bottoms
of the pages of the Advance Printing establish the months
and years of release of the Advance Printing.
Hall (1870, p. 347) wrote: “This paper was originally
printed in advance, in December, 1864, for the Eighteenth
Report on the New York State Cabinet.’ However, as in-
dicated above the Advance Printing appeared in two parts
in December, 1864 and January, 1865.
The Advance Printing of the paper on Niagaran fos-
sils was not republished in the 18th Report on the New
York State Cabinet. The copies of the 18th Report exam-
ined by me were dated 1865; the table of contents of these
copies listed a series of 10 papers under the heading: ““Con-
tributions to Palaeontology: By James Hall.’ The first of
these papers bears almost the same title as Hall’s Advance
Printing, however, none of the 10 papers was published in
the 18th Report.
In the First Edition of the 20th Report on the New
York State Cabinet (pp. 305-352) Hall republished the 48
page Advance Printing work and added to it new descrip-
tions (pp. 353-381) and supplementary notes (pp. 382-
394). The description of Amphicoclia in the First Edition
of the 20th Report (p. 339) is exactly the same as the de-
scription published in the Advance Printing (p. 35).
The 20th Report on the New York State Cabinet was
published in two editions. The title page of the First Edi-
tion bears the date 1867 and the title page of the Revised
Edition bears the date 1868. However, preceding the title
page of the Revised Edition a small slip of paper was pasted
in by the printer reading: “Note.— This Revised Edition
was completed in 1870, and the imprint should have been
so dated, instead of 1868, the date of the First Edition;”
Bassler (1915, p. 32) gave the date of the First Edition of
the 20th Report as 1868, thus, apparently the title page
of the First Edition is also misdated. On these bases, the
date of the First Edition of the 20th Report should be 1868
and that of the Revised Edition, 1870.
In the Revised Edition of 1870 Hall again reprinted
the descriptions of 1865 and 1868, although some changes
were made; however, the description of Amphicoelia (1870,
p. 386) differs only slightly from that of 1865 and 1868.
In 1871 (p. 42) Hall reprinted the 1870 description of
Amphicoelia. In all four publications (1865, 1868, 1870, and
1871) Hall listed Amphicoelia as a new genus. In 1865 and
1868 he listed it as: “Genus Leptodomus{?] (McCoy) .
while in 1870 and 1871 it
was listed as: “Genus Amphicoelia, N. G.”
Subgenus Amphicoclia (n. g.),”
It is uncertain as to how many copies of the Advance
Printing were distributed. Hall (1868, p. 383) made men-
tion of having sent out only a single copy of the 1864 por-
tion, which was sent to Winchell; whether additional copies
were sent out could not be ascertained. Presumably in
1865 Hall distributed separates containing all 48 pages of
the work. The mollusks are described only in the portion
of the work which appeared in 1865, and these descriptions
apparently had fairly wide distribution for the name Amphi-
coclia was used by Winchell and Marcy (1866), Meek and
Worthen (1866a), and Meek (1867). ‘These works predate
the publication of Amphicoelia in the First Edition of the
20th Report (1868), and the various authors refer to Hall
as the proposer of the genus.
Whether or not this constitutes publication in the sense
NortH AMERICAN AMBONYCHIIDAE: POJETA 167
of the International Code of Zoologicai Nomenclature
(2d Ed., 1964) is uncertain. The Code (p. 7, Art. 8) lists the
criteria of publication as follows:
To be regarded as published within the meaning of this Code, a
work when first issued must
(1) be reproduced in ink on paper by some method that as-
sures numerous identical copies;
(2) be issued for the purpose of scientific, public, permanent
record;
(3) be obtainable by purchase or free distribution; and
)
not be reproduced or distributed by a forbidden method
[Arts 93]:
Article 9 (p. 9) of the Code reads:
None of the following acts constitutes publication within the
meaning of the Code:
(1) distribution of microfilms, or microcards, or matter repro-
duced by similar methods;
(2) distribution to colleagues or students of a note, even if
printed, in explanation of an accompanying illustration;
(3) distribution of proof sheets;
(4) mention at a scientific or other meeting;
(5) labelling of a specimen in a collection;
(6) mere deposit of a document in a library; or
(7) after 1950, anonymous publication.
Hall’s 1865 Advance Printing was reproduced by a
method which assured identical copies; how numerous
these copies were is uncertain. Several authors prior to
1868 were familiar with the publication, and it is known
that Hall sent an inscribed separate to Theodore Gill which
was received by Gill on March 7, 1865. Presumably Hall
sent out other separates also, however, he continued to
refer to Amphicoelia as a new genus through 1871. Ap-
parently copies of the 1865 work were not available by
purchase but were sent by Hall to various colleagues. ‘The
Advance Printing does not seem to violate Article 9 of
the Code.
Bassler (1915, p. 32) did not seem to consider the Ad-
vance Printing as a valid publication. Meek and Worthen
(1868, pp. 357-358) accepted the Advance Printing as a
valid publication, although they gave the date of the generic
name as 1864, while giving 1865 as the date of origin of the
name of the type species. Neave (1939, p. 154) gave 1867
as the date when Amphicoclia was proposed. This is prob-
ably based upon the date given on the title page of the
First Edition of the 20th Report.
Hall’s 1865 work is regarded herein as a valid publica-
tion on the bases that identical copies were printed and that
a number of these copies were sent out to various interested
parties. The Code does not stipulate how many copies of a
work must be printed before they are considered to be
numerous, and small editions of other works are considered
to constitute legitimate publication.
Because Hall’s 1865 work is difficult to obtain, his
original description of Amphicoclia is quoted herein (Hall,
1865, p. 35):
Genus Leptodomus[?] (McCoy)
Subgenus Amphicoclia (n. g.)
The Acephala present great difficulties in the way of satisfactory
generic reference; and it is often scarcely possible to arrive at cer-
tainty with regard to their true relations.
A single species from Wisconsin, which is somewhat numerous
in individuals, has the general aspect of the more elevated forms of
Leptodomus of McCoy; but it cannot nevertheless be referred properly
to that genus.
The general form of the shell is subrhomboidal, with elevated
beaks. The casts present the appearance of a large triangular cartilage
pit beneath the beaks; and just anterior to this, and separated by a
thin process on each valve is an apparent second pit: or the whole
may be a large cartilage pit divided by a thin septum. No teeth have
been discovered on the extension of the hinge line. The muscular im-
pressions are faint and the shell thin.
The description is exceedingly generalized, however,
Hall did describe the type species, and in 1868 he illustrat-
ed this species. In addition, I have seen the type materials of
the type species, and an adequate concept for the name
Amphicoelia can be established.
The Swedish species Amphicoclia transplicata Isberg
was placed in this genus by Isberg (1934); it has the gen-
eral shape of Amphicoelia, including the prominent antero-
ventral salient, however, it lacks radial prosopon.
Types and materials. — The above description is based
upon Hall’s type materials of Amphicoelia leidyi (A.M.
Nos. 1949/1, 2072/1, 207272), the hypotypic materials of
Amphicociia neglecta of Whitfield (1882, U.S.N.M. No.
135946) and Kindle and Breger (1904), U.S.N.M. No.
62322), and several new specimens.
Distribution.—In North America this genus is limit-
ed to rocks of Niagaran and Cayugan age (Middle and Late
Silurian) . Niagaran species occur in Illinois, Indiana, New
York, Ohio, Ontario, Tennessee, and Wisconsin; while the
single Cayugan species occurs only in West Virginia.
SPECIES LISTING
Amphicoelia costata Hall and Whitfield, 1875
This is a medium-sized costate species found in the
Niagaran of Ohio.
Amphicoelia leidyi Hall, 1865
Plate 24, figures 3-10; Plate 25, figure 5
This is the type species of the genus; it was question-
ably placed in synonymy with A. neglecta (McChesney)
by Hall in 1870 and 1871, however, Hall (1865 and 1868)
made no mention of the possible synonymy.
Of the three specimens figured by Hall (1868, 1870,
and 1871), the specimen (A.M. No. 2072/2) shown by him
168 PALAEONTOGRAPHICA AMERICANA (V, 36)
on plate 14, figure 14 (Pl. 24, figs. 8-10) is chosen as the
lectotype of the species Amphicoelia leidyi Hall, 1865.
The measurements of this specimen are: length, 57 mm.;
height, 53 mm.; thickness of a single valve, 16 mm.; and
diagonal dimension, 59 mm.
A. Ieidyi has been reported from the Niagaran of Hlin-
ois, Indiana, Tennessee, and Wisconsin. Hall’s 1879 speci-
mens of 4. Ieidyi from the Niagaran of Indiana (PI. 25,
fig. 3) are too poorly preserved to be properly identified.
Amphicoelia neglecta (McChesney), 1861
Plate 24, figures 11, 12; Plate 25, figures 1, 2
This specific name was questionably placed in syn-
onymy with A. leidyi by Hall (1870 and 1871); Winchell
and Marcy (1866), Meek and Worthen (1868), and Whit-
field (1882) regarded the two names as synonyms.
McChesney described this species in 1861, but did not
figure it until 1865. I have not seen McChesney’s original
material, however, his 1865 figure 2a, plate 9, compares
favorably with Hall’s type specimens of 4. letdy:, and the
two names are probably synonyms for the same species.
A. neglecta has been reported from the Niagaran of Illinois,
Indiana, Ontario, and Wisconsin.
Amphicoelia orbiculata (Hall), 1852
This Niagaran form was questionably placed in Awvi-
cula by Hall (1852, p. 284) as Avicula? orbiculata (n.sp.) .
Previously (1843, p. 202) Hall had described a Devonian
species as Avicula orbiculata, n. sp., which he subsequently
(1883 and 1884a, b) placed in the genus Lyriopecten Hall
as L. orbiculatus. See Newell (1938, p. 38) for a discussion
of Lyriopecten orbiculatus (Hall) , 1845.
Whitfield and Hovey (1899, p. 156) placed Avicula?
orbiculata Hall, 1852, in the genus Amphicoelia as A.
orbiculata; Bassler (1915, p. 33) accepted the assignment
to Amphicoelia. Grabau (1901, p. 208) named the new
species Lyriopecten orbiculoides; he listed this species as:
“Lyriopecten orbiculoides (nom. nov.) cf. Avicula (?)
orbiculata Hall (1852, Pal. N.Y. 2:284, pl. 59) ~ he
identification with Hall’s species and the generic reference
are provisional.”
Hall’s original figure of this species is of a poorly
preserved right valve which shows no radial prosopon, and
the placement of the species in Amphicoclia must be
considered as tentative.
Amphicoelia ulrichi Maynard, 1913
This is a costate species reported only from the Late
Silurian of West Virginia.
In Europe Isberg (1934) assigned the concentrically
marked species Amphicoclia transplicata Isberg to this
genus. Winchell and Marcy (1866) suggested that Amphi-
coelia leidyi be compared to Avicuia triton Salter, and Is-
berg (1934) placed this latter species in Amphicoelia. As
figured by Hind (1910) Amphicoelia triton is a costellate
species with a prominent anteroventral salient; he reported
the species as in the Llandeilian (Middle Ordovician) and
Llandoverian (Early Silurian) of Scotland. The specimens
of A. triton figured by Hind probably belong to Amphi-
cociia. Hind’s figures are of much smaller specimens than
Salter’s original figure (1848), and whether the Llandeilian
and Llandoverian materials belong to the same species is
uncertain. No North American species of Amphicoelia is
known from rocks as old as those of Chazyan age.
Remarks. —1 could not confirm some of the details of
the morphology of the genus on the materials available to
me, and the following morphological details are known
only from the descriptions of previous authors.
Meek and Worthen (1868) and Winchell and Marcy
(1866) reported the presence of a longitudinally striated
ligamental area; undoubtedly they were writing of a dupli-
vincular type of ligament. Winchell and Marcy (1866) de-
scribed a “duplex, crescentic posterior muscular scar,” in-
dicating the presence of both a posterior adductor and a
posterior byssal-pedal retractor muscle; specimens at my
disposal show only remnants of the posterior adductor scar.
Meek and Worthen (1868) considered the genus to be
edentulous, however, Winchell and Marcy (1866) described
cardinal teeth; because of this discrepancy the dentition
of the genus is herein regarded as unknown.
Meek and Worthen (1868, p. 385) described the genus
as being slightly inequivalved:
The almost, if not quite, equivalve character of this shell might
be supposed to throw doubts upon the suggestion that it belongs to the
Aviculidae. The fact, however, that its broad, striated cardinal area
inclines more or less over to the right, in both valves, indicates a
want of exact symmetry of the two valves not at all apparent in the
internal cast, and much as we often see in Myalina, and other types of
that family.
I have seen no shelled specimens of this genus and, as in-
dicated by Meek and Worthen, molds and casts show an
equality of the valves. Hall considered the type species of
the genus to be equivalved, and no other authors mention
a possible inequality of the, valves. Perhaps Meek and Wor-
then had distorted materials; they do not figure any
shelled specimens. Until shelled materials are figured which
show valve inequality it seems best to consider the genus
to be equivalved on the basis of the known molds and casts.
Hall, in the original description of the genus, wrote of
NortH AMERICAN AMBONYCHIIDAE: POJETA 169
a large triangular ‘‘cartilage’ pit beneath the beaks, just
anterior to which is a second such pit. Alternatively he
thought that the two pits might be a single such structure
divided by a thin septum. What Hall had in mind when
he described these pits is uncertain. Molds often show a
prominent space between the incurved beaks and the plane
of commissure (PI. 24, fig. 8) which presumably was oc-
cupied by the ligamental area; however. there are no
structures resembling resilifers.
Meek (1867, p. 173) described what he called “little
ears” between the beaks of Amphicoelia: “A cavity
exists between the beaks of Amphicoclia, Hall, from the
Upper Silurian; and internal casts of these look very much
like little ears . . . ; but good specimens of the shell pre-
serving perfectly the anterior margins of the valves, show
clearly that there is no external anterior ear whatever.”
What cavity Meek had in mind is uncertain; however, in
one of Hall's paralectotypes of Amphicoclia leidyi there
is a small projecting structure forward of the beaks (PI.
24, fig. 7). This projection may be the “little ear” of Meek
and the anterior ‘“‘cartilage’” pit of Hall. I have seen the
structure only on the paralectotype mentioned above; it
may represent the filling of some shell cavity such as a
muscle scar, or it may not be organic in its origin.
Hall originally described Amphicoclia as a subgenus
of Leptodomus McCoy, 1844. This assignment was disputed
by Meek and Worthen (1866a and 1868) and by Winchell
and Marcy (1866); by 1870 Hall regarded Amphicoclia as
a distinct genus.
On Whitfield’s (1882) hypotype of 4. neglecta the cos-
tellae vary somewhat in size around the ventral edge (PI.
25, fig. 2). This feature suggests that there may have been
some costellate multiplication in at least some individuals
belonging to Amphicoelia.
Genus ANOMALODONTA Miller, 1874
Plates 25-29
1874. Anomalodonta Miller [partim], Cincinnati Quart. Jour. Sci.,
vol. 1, pp. 16 and 326.
1874. Megaptera Meek and Worthen [partim], White, American Jour.
Sci. and Arts, vol. 108, p. 218.
1875. Anomalodonta Miller [partim], Cincinnati Quart. Jour. Sci.,
vol. 2, p. 280.
1875. Opisthoptera Meek [partim], White, American Jour. Sci. and
Arts, vol. 109, p. 318.
1881. Anomalodonta Miller, Zittel, Handbuch der Palaeontologie,
Abt. 1, Band 2, p. 36.
1889. Anomalodonta Miller [partim], North American Geol. and
Palaeont., p. 462.
1893 (1895). Anomalodonta Miller [partim], Ulrich, Geol. Sur. Ohio,
Rep., vol. 7, p. 636.
1908. Anomalodonta Miller [partim], Cumings, Dept. Geol. and
Nat. Resources Indiana, 32d Ann. Rep., pp. 978 and 987.
1909. [Non] Anomalodonta Miller, Grabau and Shimer, North Amer-
ican Index Fossils, vol. 1, p. 430.
1926. [?] Anomalodonta Miller [partim], Hussey, Mus. of Geol.
Univ. of Michigan, Contrib., vol. 2, No. 8, p. 166.
1931. Anomalodonta Miller, McFarlan, in Jillson, Kentucky Geol.
Sur., Paleont. of Kentucky, p. 113.
Type species.—Anomalodonta gigantea Miller, 1874a
(p. 17), by subsequent designation of Miller, 1874c¢ (p.
a}3)) es
Diagnosis. — Large simplicicostate monomyarian Am-
bonychiidae lacking lateral teeth and with only a single
poorly developed cardinal tooth in the right valve.
Description. — Equivalved, inequilateral shells lacking
an anterior lobe; beaks terminal and prosogyral; obliquity
prosocline; prosopon composed of concentric growth lines
and simple radial costae; ostracum two layered; byssal sinus
more or less prominent; byssal gape long, wide, fusiform;
size large.
Ligamental area possessing duplivincular grooves and
ridges which run the length of the cardinal margin, liga-
mental areas do not diverge greatly, diverge more posteriorly
than anteriorly; pallial line integropalliate, attachment dis-
continuous throughout almost its entire length, terminates
in the umbonal cavity just below beaks; only one adductor
muscle (the posterior) is present, it is located subcentrally;
dorsal to the posterior adductor scar is a smaller posterior
byssal-pedal retractor scar, there is a large bifid anterior
byssal retractor scar behind the beak on the posterior um-
bonal slope; dentition composed of a small poorly developed
cardinal tooth in the right valve, and a socket in the left
valve, no lateral teeth, essentially edentulous.
Synonymic discussion. — This genus contains only one
species Anomalodonta gigantea Miller. Most references to
the genus include several other species besides A. gigantea
and, thus, refer only in part to Anomalodonta; these other
species are no longer assignable to this genus.
Hussey’s 1926 species A. griffini belongs to Opisthop-
tera. Concerning the other material he assigned to Anomalo-
donta, the hinge line is known in none of these and, thus,
they can be assigned only questionably to the genus.
Distribution. —So far as known this genus is limited
to the Late Cincinnatian (Richmond) Arnheim and
Waynesville formations in the Tristate Area of Ohio, In-
diana, and Kentucky. It may also occur in the Richmond of
Michigan and Ontario (Whiteaves, 1909) .
Species listing —Only one species is at present as-
signed to this genus, Anomalodonta gigantea Miller. Megap-
tera [Opisthoptera] casei Meek and Worthen which was
placed in the genus by Miller is the type species of
Opisthoptera and differs from Anomalodonta gigantea in
the possession of a posterior wing and multiple ribs.
Ambonychia costata Meek which was placed in Ano-
170 PALAEONTOGRAPHICA AMERICANA (V, 36)
malodonta by Ulrich (1893 (1895), p. 637) and Ambony-
chia alata Meek which was transferred to Anomalodonta
by Miller (1874a, p. 16) are herein considered to be syn-
onyms. The species Anomalodonta alata (Meek) possesses
both cardinal and lateral teeth and is herein returned to
the genus Ambonychia Hall, as Ambonychia alata Meek.
Anomalodonta plicata Ulrich (Pl. 26, figs. 7-8) is
founded upon poor material, and it is doubtful if its
proper generic assignment can be ascertained. Anomalo-
donta griffini Hussey belongs to the genus Opisthoptera
and will be discussed under that genus.
Remarks and comparisons. — Anomalodonta seems to
be closely related to the genus Ambonychia Hall, from
which it differs only in its dental structures. Both genera
are simplicicostate, monomyarian, and have a prominent
byssal gape. These genera form part of a Late Ordovician
expansion of ribbed, monomyarian ambonychiids.
SPECIES DESCRIPTION
Anomalodonta gigantea Miller, 1874
Plate 25, figures 6-10; Plate 26, figures 1-6, 9-14; Plate 27, figures
1-9; Plate 28, figures 1-9; Plate 29, figure 1
1874. Anomalodonta gigantea Miller, Cincinnati Quart. Jour. Sci., vol.
1, pp. 17 and 327, figs. 7-9.
1889. Anomalodonta gigantea Miller, North American Geol. and
Palaeont., pp. 462-463, figs. 776-778. [Same figures as Miller,
1874. ]
1893 (1895). Anomalodonta gigantea Miller, Ulrich, Geol. Sur.
Ohio, Rep., vol. 7, p. 637, pl. 50, figs. 1-4.
1908. Anomalodonta gigantea Miller, Cumings, Dept. Geol. and Nat.
Resources Indiana, 32d Ann. Rep., p. 968, pl. 43, figs. 1-1b.
[Same figures as Ulrich, 1893 (1895).]
1915. Anomalodonta gigantea Miller, Butts, Kentucky Geol. Sur.,
ser. 4, vol. 3, part 2, p, 48, pl. 8, fig. 20.
1926. [?] Anomalodonta sp. cf. gigantea [Miller], Hussey, Mus. of
Geol., Univ. of Michigan, Contrib., vol. 2, No. 8, p. 166, pl. 3,
fig. 7.
1931. Anomalodonta gigantea Miller, McFarlan, in Jillson, Kentucky
Geol. Sur., Paleont. of Kentucky, p. 113, no fig.
1955. [?] Anomalodonta gigantea [Miller], Caster, Dalvé, and Pope,
Elem. Guide to the Fossils and Strata of the Ordovician in the
Vicinity of Cincinnati, Ohio, p. 41, pl. 5, fig. 31.
Diagnosis. — Anomalodonta with 30-40 costae.
Description. — Shell quadrate; possessing 30-40 costae;
angle gamma, 90-100 degrees; umbones rounded, not keeled,
projecting 2-5 mm. above the cardinal margin; greatest
convexity of a single valve, up to 20 mm.; diagonal dimen-
sion, up to 100 mm.; byssal gape wide, up to 12 mm. long,
in shelled materials located about its length below the peaks
of the umbones, in molds located about half its length be-
low the umbonal peaks; byssal sinus more or less prominent;
size large.
Musculature, ligamental area, and dentition com-
pletely known, and as in the generic des¢ ription.
Types and materials—The above description is based
upon Miller's original syntypic suite (W.M. No. 8851) , one
of Ulrich’s 1893 (1895) hypotypes (U.S.N.M. No. 46088) ,
Hussey’s figured specimen (U.M. No. 9825), and eight new
specimens. Of the latter, the three loaned to the author by
Dr. A. L. McAlester of the Peabody Museum (Y.P.M. Nos.
23323, 23324, and 23325) are especially well preserved and
illustrate the complete hinge line of the species.
None of Miller's original syntypes are complete, and
the original author prepared the materials poorly (PI. 26,
figs. 1-6); the duplivincular ligamental structures were
carved in, rather than exposing the original grooves and
ridges, as were the large tooth and socket which appear to
traverse the entire ligamental area. The new materials
show that the dental structures are entirely below the
ligamental area as is typical of ambonychiids. Miller’s ma-
terials are unique in that two of his four specimens show
what appears to be prismatic structure in both ostracal lay-
ers. Of Miller’s syntypes the one figured by him on page 17,
figure 7, and herein figured on Plate 25, figures 6-8 is
chosen as the lectotype of the species. None of Miller’s
specimens are complete and, thus, no measurements are
given; in addition, none of his specimens show the complete
costal number of the species. The lectotype has several lay-
ers of paper glued to its exterior surface, thus, its outer sur-
face is unknown. The paper was glued on by Miller be-
cause of the fragmentary nature of the specimen.
The new materials described herein are the first speci-
mens of this species to be described in the literature since
Ulrich, 1893 (1895).
Distribution.—The distribution of this species is the
same as that of the genus.
Remarks and comparisons.—Miller in his original
description of this species figured and mentioned what he
considered to be an anterior adductor muscle scar. He in-
terpreted a low anteroventral shell fold (PI. 25, fig. 8) as
a muscle scar. This is just an irregularity in the inner ostra-
cum of the shell; such irregularities are not uncommon
among some groups of pelecypods such as the unionids. This
particular fold does not have the characteristics of a muscle
scar; in addition, the pallial line continues past this fold
into the umbonal cavity; nowhere along the course of the
pallial line is there an expansion which might indicate
the presence of an anterior adductor scar. Thus, the genus
is herein regarded as monomyarian.
Miller (1874a, p. 16) interpreted the grooves and
ridges seen in the growing margin of the shell (PI. 28,
figs. 7-8) as “‘cartilage’’ grooves. As discussed in the mor-
phology section of this work, the marginal grooves and
NortH AMERICAN AMBONYCHIIDAE: POJETA {71
ridges probably had nothing to do with ligamental inser-
tions.
Ulrich’s (1893 (1895) ) criterion for recognizing in-
ternal molds of this genus was the presence of “a variable
number of large, irregular folds’’ below the posterior liga-
mental area. On this basis he created the species Anomalo-
donta plicata (Pl. 26, figs. 7-8) for a single specimen in
which the hinge structure is unknown. While the lectotype
of A. gigantea (PI. 25, fig. 8) shows a shell thickening in this
region, such a thickening is not present in other shelled spec-
imens (PI. 28, fig. 1). Such a generic criterion would be
difficult to apply because irregularities in the inner shell
surface of living forms are not consistent from individual
to individual.
Anomalodonta gigantea can be distinguished from
other large simplicicostate Richmond forms (which at pres-
ent are assigned to the genus Ambonychia Hall) by the lack
of umbonal carination in Anomalodonta. Because the denti-
tion of the large Richmond Ambonychias is almost un-
known, some of them may eventually have to be reassigned
to Anomalodonta.
Genus ANOPTERA Ulrich, 1893 (1895)
Plates 28, 29
1893 (1895). Anoptera Ulrich, Geol. Sur. Ohio, Rep., vol. 7, p. 649.
1918. Clionychia Foerste, Ottawa Naturalist, vol. 31, p. 121.
Type species. — Anoptera miseneri Ulrich, 1893 (1895)
(p. 650), by monotypy.
Diagnosis. —Small_ Ambonychiidae with concentric
prosopon, prominent byssal sinus, and with the height
greater than the length.
Description.—Shell equivalved, inequilateral, rectangu-
lar and erect, and lacking an anterior lobe; beaks terminal
and prosogyral, project far forward; prosopon composed of
concentric growth lines only, these are numerous, promi-
nent, and almost imbricating; only outer shell layer known,
indicating a two layered shell; no discernible byssal gape;
byssal sinus prominent; size small; height greater than
length, and approaching the diagonal dimension.
Internal and ligamental features unknown except for
the presence of a bifid anterior byssal retractor scar in one
species.
Synonymic discussion.—This genus was founded for a
species of Richmond shells which occurs in the Tristate
Area of Ohio, Indiana, and Kentucky. It is not well known,
but on the basis of the evidence available at present it seems
to be distinct.
Foerste’s 1918 species Clionychia angusta from north-
ern Michigan is similar to Anoptera miseneri Ulrich and is
herein reassigned to Anoptera. Anoptera angusta pOssesses
the concentric prosopon of the Middle Ordovician genus
Cleionychia Ulrich; however, it is similar to Anoptera in
the presence of the closely crowded growth lines, the prom-
inent byssal sinus, the projecting beaks, and in the height
being greater than the length.
Distribution.—This genus is limited to rocks of Rich-
mond age in the Tristate Area of Ohio, Indiana, and Ken-
tucky, in Michigan, and perhaps in Ontario, Canada.
Species listing.—Only two species are presently assigned
to the genus: Anoptera miseneri Ulrich, 1893 (1895) and
Anoptera angusta (Foerste) , 1918.
Remarks and comparisons. — Ulrich (1893 (1895) ) de-
scribed the genus as having an edentulous hinge line, an in-
ternal ligament, and a posteroventrally placed posterior ad-
ductor muscle scar, and he described the pallial line. None
of the known material of the genus shows any of these struc-
tures unequivocally.
This genus is similar to Cleionychia Ulrich of the
Middle Ordovician. It differs in the much more numerous
growth lines, the more prominent byssal sinus, and the
relationship of the length to the height of the shell; in
Cleionychia the length and height are subequal with the
length usually being the greater. In addition, the promi-
nent byssal sinus and relatively small length of the shell give
Anoptera an appearance different from that of any species
assigned to Cleionychia.
SPECIES DESCRIPTIONS
Anoptera miseneri Ulrich, 1893 (1895)
Plate 28, figures 10-17; Plate 29, figures 2-6
1893 (1895). Anoptera miseneri Ulrich, Geol. Sur. Ohio, Rep., vol.
7, p. 650, pl. 50, figs. 5-9.
1925. [2] Anoptera cf. miseneri Ulrich, Dyer, Ontario Dept. Mines,
Ann. Rep., vol. 32, pt. 7, 1923, p. 57.
Diagnosis. — Anoptera with closely spaced growth lines,
and angle gamma close to 90 degrees.
Description. — Shell ovately rectangular, erect; angle
gamma, about 90 degrees; umbones rounded, and with a
prominent space between their anterior faces and the mid-
sagittal plane of the shell (in molds) ; thickness of a single
valve, 3-5 mm.
Interior unknown, except for a bifid anterior byssal
retractor scar.
Types and materials. — ‘The above description is based
upon Ulrich’s original syntypic series (U.S.N.M. Nos.
46090, 46091, 142814) , and two additional specimens. This
is an uncommon species, which in part accounts for the few
known specimens and the lack of knowledge of most mor-
172 PALAEONTOGRAPHICA AMERICANA (V, 36)
phological details. None of the materials of this species is
well preserved; specimens being various types of molds and
casts, or preserving only the external ostracal layer.
Of Ulvich’s original syntypes the specimen figured here
on Plate 28, figures 10-12 is chosen as the lectotype; this
specimen was figured by Ulrich on his plate 50, figures 5-6,
(1893 (1895) ). The dimensions of the lectotype are: length,
16 mm.; height, 20 mm.; thickness of a single valve, 3 mm.;
and diagonal dimension, 21 mm. The paralectotype figured
herein on Plate 28, figures 14-17 has the following measure-
ments: length, 20 mm.; height, 24 mm.; thickness of a single
valve, 4 mm.; and diagonal dimension, 26 mm.
Distribution. — This species occurs in the Tristate Area
of Ohio, Indiana, and Kentucky, in the Waynesville and
Whitewater formations (Richmond), and perhaps in the
Richmondian rocks of Ontario, Canada. The only speci-
men collected by the author is from the Whitewater forma-
tion of Indiana.
Anoptera angusta (Foerste), 1918
Plate 29, figures 7-9
This species was originally referred to Cleionychia by
Foerste as explained above. Foerste’s holotype (U.S.N.M.
No. 78463) has the following dimensions: length, 17 mm.;
height, 23 mm.; thickness, 3 mm.; and diagonal dimension,
27 mm.
There seems to be no significant difference between
this species and Anoptera miseneri; both names may refer to
the same species, but more material of A. angusta is needed
before this can be determined.
Hussey’s (1926) specimens of A. angusta (U.M. Nos.
9818, 9819) are herein figured on Plate 29, figures 8, 9.
They are probably poorly preserved specimens of 4. an-
gusta.
Genus AMBONYCHIA Hall, 1847
Plates 29-32
For the synonymic, taxonomic, and morphologic details
of this genus see Pojeta (1962). Only such new facts and
materials as have been discovered since that monograph are
considered herein. As discussed above under the genus
Ambonychiopsis (p. 160) the name Ambonychia must be
based upon the species A. radiata Hall, 1847, rather than on
A, bellistriata Hall, 1847 as was heretofore thought to be the
case. This invalidates the generic name Byssonychia Ulrich,
1894 which was used for this genus by Pojeta (1962).
Diagnosis.—Simplicicostate
monomyarian Ambony-
chiidae, with cardinal and posterior lateral teeth.
New materials and species descriptions—Only one
species is discussed here in detail; this is the form which has
been known by the name Anomalodonta alata (Meek). New
materials show that this species possesses both cardinal and
posterior lateral teeth, and it is, therefore, reassigned to
Ambonychia. In addition to this detailed description, sev-
eral other species are briefly mentioned, because of the
finding of new specimens which show hitherto poorly
known morphological details.
Ambonychia alata Meek, 1872
Plate 29, figures 10-19; Plate 30, figures 1-14, 16-21; Plate 31,
figures 1-6; Plate 47, figure 1
1871. Ambonychia costata James [nomen nudum], Catalogue of the
Lower Sil. Fossils, Cincinnati Group, p. 13.
1872. Ambonychia (Megaptera) alata Meek, Acad. Nat. Sci. Phila-
delphia, Proc. for 1871, part 3, p. 319, no fig.
1873. Ambonychia costata James, Meek, Geol. Sur. Ohio, Rep., vol.
1, part 2, Palaeont., p. 130, pl. 12, figs. Sa-c.
1873. Ambonychia (Megaptera) alata Meek, Geol. Sur. Ohio, Rep.,
vol. 1, part 2, Palaeont., p. 131, pl. 11, fig. 9 and pl. 12, fig. 10.
[Reprinting of Meek, 1872 above.]
1874. Ambonychia costata [Meek], Miller, Cincinnati Quart. Jour,
Sci., vol. 1, p. 15, no fig.
1874. Anomalodonta alata (Meek), Miller, Cincinnati Quart. Jour.
Sci., vol. 1, pp. 223 and 328, no fig. [P. 223 is a reprinting of
Meek, 1872 above. ]
1889. Anomalodonta alata Meek, Miller, North American Geol. and
Palaeont., p. +62, no fig.
1893 (1895). Anomalodonta costata Meek, Ulrich, Geol. Sur. Ohio,
Rep., vol. 7, p. 637, no fig.
1893 (1895). Anomalodonta alata Meek, Ulrich, Geol. Sur. Ohio,
Rep., vol. 7, p. 638, pl. 46, fig. 1.
1908. Anomalodonta costata Meek, Cumings, Dept. Geol. and Nat.
Resources Indiana, 32d Ann. Rep., p. 987, pl. 42, figs. 6-6a.
[Description and figures after Meek, 1873 above.]
1909. Anomalolonta alata (Meek), Grabau and _ Shimer,
American Index Fossils, vol. 1, p. 431, no fig.
1916. Anomalodonta alata Meek, Foerste, Sci. Labs. Denison Univ.,
Bull., vol. 18, p. 326, pl. 4, fig. 2.
1916. Anomaladonta costata Meek, Foerste, Sci. Labs. Denison Univ.,
Bull., vol. 18, p. 328, pl. 4, fig. 3.
North
Diagnosis. — Ambonychia possessing 25-35 costae and
small posterior wing; posterior lateral teeth removed some
distance anteriorly from the posterodorsal margin.
Description. — Shell alate posteriorly; possessing 25-35
costae; obliquity prosocline; angle gamma, 85-95 degrees;
angle beta, 70-80 degrees; umbones noncarinate, projecting
2-3 mm. above the cardinal margin; size medium to large;
thickness of a single valve, up to 13 mm.; byssal sinus more
or less prominent; byssal gape fusiform, up to 10 mm. long,
located about its length below the umbonal peaks; liga-
mental areas erect, diverging more posteriorly than anter-
iorly; shelled specimens usually have prominent growth
varices.
Posterior musculature typical for the genus, consisting
of a large subcentral posterior adductor and a smaller byssal-
pedal retractor above it; behind each beak there is a small
NortH AMERICAN AMBONYCHIDAE: POJETA Wi
bifid anterior byssal retractor scar; pallial line typical for
the genus; ligamental areas covered by duplivincular
grooves and ridges; cardinal dentition consisting of three
teeth in the left valve and two in the right valve, attached
to a vertical septum; two posterior lateral teeth in each
valve, anterior one much longer than the posterior one,
both attached directly to the interior of the valve below
the ligamental areas, not attached to a separate vertical
septum; posterior dentition not parallel to cardinal margin
but at an angle to it.
Synonymic discussion. — This species was originally as-
signed to Megaptera [Opisthoptera] by Meek, on the basis
of the presence of a posterior alation. It differs from O pis-
thoptera in that the wing is much smaller and, more im-
portantly, in that the costae are simple and not multiple.
Miller (1874a) reassigned the species to the simplicicostate
genus Anomalodonta. However, the dentition of that genus
consists only of a single poorly developed tooth in one
valve, whereas, Ambonychia has both well-developed car-
dinal teeth and posterior lateral teeth. This difference in
dentition is the only taxobasis separating the two genera
and, thus, the species is herein reassigned to Ambonychia
as A. alata Meek.
The two species names Ambonychia costata and A.
alata are herein considered to be synonyms. A. costata was
a nomen nudum by James in 1871, and the only known
specimen ever called by this name was given to Meek by
James and it was not described by Meek until 18753.
Meek credited the species name to James, but this is not ac-
ceptable by the modern rules of nomenclature; the first
author to use a species name with a description receives
credit for the name. Thus, A. costata dates from 1873. In
the meantime, the species name A. alata was proposed by
Meek in 1872. Because the two are herein considered as
synonyms the species has to be known as 4. alata, the name
under which it was first described (Meek, 1872).
Types and materials. —'Vhe above description is based
upon the holotype of Ambonychia costata (W.M. No. 790) ,
plastotypes of Ambonychia alata (U.S.N.M. No. 67520 and
142815), Ulrich’s hypotype of Anomaiodonta alata
(U.S.N.M. No. 46087), Foerste’s hypotype of A. alata
(U.S.N.M. No. 84928), and fifteen new specimens of the
species. Meek’s original syntypic series of Ambonychia
(Megaptera) alata was examined by Foerste at the Walker
Museum in 1916 (W.M. No. 2341), however, these speci-
mens can no longer be located. Because they were at the
Walker Museum in the not too distant past they may be
relocated; in the meantime the plastotypes at the U.S.N.M.
give an adequate idea of the concept implied by the name
Ambonychia alata. Unfortunately Foerste did not figure
Meek’s types, however, he did discuss each specimen.
The plastosyntypic suite of Meek’s original materials
of A. alata at the U.S.N.M. (Nos. 67520 and 142815) con-
sists of two specimens, only one of which was figured by
Meek (1873). The plastosyntype shown on Plate 29, fig-
ure 10 was made from the specimen figured by Meek on
plate 12, figure 10; the specimen used by Meek for this
figure is herein chosen as the lectotype of Ambonychia
(Megaptera) alata Meek, 1872. Foerste (1916) examined
Meek’s original materials and according to him the lecto-
type had 28 costae; on the plastolectotype 27 plus costae can
be counted. The specimen used by Meek for his figure 9,
plate 11, is herein regarded as a paralectotype of the species;
no plastotype of this specimen could be located, however,
Foerste (1916, p. 327) noted that the original had 24 plus
costae.
In addition to the two primary types figured by Meek,
Foerste (1916) noted the presence of a third specimen in
the type suite of 4. alata; he felt that this specimen had
been added to the type suite after Meek had figured the
above two primary types. While Foerste’s assertion may be
correct, there is nothing in the literature to support his
claim, and this third type of A. alata is herein regarded as
an unfigured paralectotype. There is a plaster mold of the
third type specimen at the United States National Museum
(PI. 29, fig. 11) which shows 29 plus costae.
The holotype of Ambonychia costata (Pl. 29, figs. 14-
17) is a poorly preserved specimen with the following di-
mensions: length, 26.5 plus mm.; height, 37 mm.; thickness
of a single valve, 7 mm.; diagonal dimension, 40 mm.; and
20 plus costae. Ulrich’s (1895 (1895) ) hypotype of Anomalo-
donta alata (Pl. 29, figs. 12-13) is incomplete and not so
well preserved as he indicated in his figure, however, it does
show the posterior lateral teeth well. Ulrich interpreted
these teeth to be the irregular posterior cardinal folds which
he regarded as characteristic of the genus Anomalodonta.
Foerste’s (1916) hypotype of Anomalodonta alata (Pl. 29,
figs. 18-19) is an adult specimen with the following dimen-
sions: length, 65 mm.; height, 66 mm.; thickness of a single
valve, 13 mm.; diagonal dimension, 70 mm.; and 25 plus
costae.
Most of the new materials of this species consist of
shelled specimens which show various portions of the
hinge line. One specimen (PI. 31, fig. 4) preserves almost
the entire hinge line.
Distribution. — As far as known Ambonychia alata is
restricted to the Richmond Arnheim and Waynesville for-
174 PALAEONTOGRAPHICA AMERICANA (V, 36)
mations of the Tristate Area of Ohio, Indiana, and Ken-
tucky.
Remarks and comparisons. — The placing of A. costata
in synonymy with A. alata is based upon the lack of any
discernible objective distinctions between the holotype of
the former species and numerous specimens of the latter.
The only distinctions which Foerste (1916) could find be-
tween the two were that in A. costata the costae were nar-
rower and that it is a smaller species. However, it is possible
to find intermediates in size between the two forms; as for
the narrower costae, the width of these is dependent upon
the age, weathering of the specimen, and whether or not
shell material is present. In addition, Foerste (1916, p. 328)
noted: “. these features [of A. costata] are possessed also
by Anomalodonta [Ambonychia] alata during its younger
stages . . .” Because there is no objective way to tell 4.
costata from A. alata the two species names are herein
placed in synonymy.
Angle gamma of the species seldom exceeds 95 degrees,
although in one specimen with the typical dentition of the
left valve of the species the angle reaches 100 degrees (PI.
30, fig. 1).
In most species of Ambonychia where the posterior
dentition is known it occurs almost at the posterior end
of the cardinal margin, while in 4. alata it is removed some
distance forward from the posterior end of the hinge line.
This may be due to the development of the small subtle
wing of A. alata. In all other respects the species has the
typical characteristics of the genus Ambonychia. Among
the Upper Ordovician (Richmond) forms, 4. alata is the
only species which possesses a costal number as low as 35.
Ambonychia ulrichi (Pojeta), 1962
Plate 31, figures 7-11
A re-examination of Hall’s 1859 hypotypes of Ambony-
chia radiata (pp. 110 and 523) shows that the specimen has
two cardinal teeth. The posterior dentition is not preserved
or else is covered over with an artifactural matrix; Hall’s
original figure shows two posterior lateral teeth. This speci-
men has only 36 costae and an angle gamma of 80 degrees.
Both of these characteristics are found in the Cincinnatian
species A. wlrichi, and Hall’s 1859 specimen is herein placed
in that species. This extends the range of 4. ulrichi into the
Ordovician of ‘Tennessee.
Ambonychia cultrata (Ulrich), 1893 (1895)
Plate 32, figures 1, 2
New material of this species shows that it has a typical
duplivincular ligament, not a “channel-like’”” one as was
heretofore supposed.
Ambonychia obesa (Ulrich), 1893 (1895)
Plate 31, figures 15-17
The pallial line, posterior musculature, and_ bifid
anterior byssal retractor scars are figured.
Genus BYSSOPTERIA Hall, 1883
Plates 32, 47
1883. Byssopteria Hall, Nat. Hist. New York, Geol. Sur. New York,
Palaeont., vol. 5, part 1, Lamellibranchiata Plates and Ex-
planations, p. 4, pls. 32 and 80. [Published prior to the entire
vol. 5, part 1.]
1884. Byssopteria Hall, New York State Cab. Nat. Hist., 35th Ann.
Rep., pp. 400 and 406d.
1884. Byssopteria Hall, Geol. Sur. New York, Palaeont., vol. 5, part 1,
Lamellibranchiata 1, pp. xiv and 252.
1885. Byssopteria Hall, Geol. Sur. New York, Palaeont., vol. 5, part
1, Lamellibranchiata 2, pl. 80. [No text for this genus.]
1886. S. g. Byssopteria Hall, Fischer, Manuel de Conchyliologie, p.
963.
1889. Byssopteria Hall, Miller, North American Geol. and Palaeont.,
p. 468.
1891. [?] Byssopteria Hall, Frech, Abhandlungen zur geologischen
Specialkarte von Preussen und den Thuringischen Staaten,
band 9, Heft 3, p. 133.
1904. [?] Byssopteria? [Hall], Reed, South African Museum, Annals,
vol. 4, part 6, p. 265.
1924. [?] Byssopteria Hall, Fenton and Fenton, Univ. Michigan, Mus.
of Geol., Contrib., vol. 1, p. 171.
1963. [?] Byssopteria ? Hall, Talent, Geol, Sur. Victoria, Mem. 24,
p. 99.
Type species. — Byssopteria radiata Hall, 1883 (pl. 32,
figs. 21-22 and pl. 80, fig. 11), by monotypy (synonymous
with Mytilarca radiata Hall in Miller, 1877, p. 197 a nomen
nudum ).
Diagnosis. — Large, nonwinged, multicostate Ambony-
chiidae.
Description. — Shell inequilateral, truncated anteriorly;
beaks prosogyral, apparently terminal; no anterior lobe;
obliquity prosocline; prosopon of concentric growth lines,
and both subdividing and intercalating costae, as well as
seemingly simple costae; byssal sinus prominent; byssal gape
unknown; nonalate; size large.
All internal features completely unknown.
Synonymic discussion.— The name Byssopteria was
proposed for multicostate Devonian forms. The species
placed in the genus by Fenton and Fenton and by Reed do
not show multiple costae. Frech’s 1891 specimen shows mul-
tiple costae but does not appear to be an ambonychiid.
Distribution. — All of Hall’s material of this genus is
listed as coming from the “Upper Chemung group at Mans-
field, Tioga County, Pa.” Williams and Kindle (1905, pp.
118 and 125) noted the occurrence of Byssopteria at both
Mansfield and Canoe Camp, ‘Tioga County, Pennsylvania,
in beds of Chemung age. As far as known the genus is
limited to the Late Devonian of Pennsylvania. The species
assigned to this genus by Fenton and Fenton from the
NorTH AMERICAN AMBONYCHIIDAE: POJETA ]
Hackberry Stage (Late Devonian) of Iowa does not show
multiple costae. However, the costae are not preserved in
the upper umbonal region of their specimen. The species
may belong to the genus, but this is uncertain at the present
time. The South African form questionably placed here by
Reed is poorly preserved and is simplicicostate; it probably
does not belong to the genus. Frech’s 1891 species does not
have the shell shape of an ambonychiid, but does show mul-
tiple costae; it is doubtful if it belongs to Byssopteria.
SPECIES LISTING
Byssopteria radiata Hall, 1883
Plate 32, figures 3-7; Plate 47, figures 2-4
Hall had three specimens in his original syntypic series
of this species; of these the two figured by him on plate
32 (1883 and 1884b) were located too late to be figured
herein (W.M. No. 10900). The specimen figured by Hall
on Plate 80, figure 11 (1883 and 1885) is preserved at the
New York State Museum (N.Y.S.M. No. 2294) and is here-
in chosen as the lectotype of the species (PI. 32, fig. 7; PI.
47, figs. 2-3). Its measurements are: length, 50 mim.; height,
62 mm.; thickness, 6 plus mm.; and diagonal dimension, 64
mm. The Walker Museum specimens are regarded as para-
lectotypes.
At the American Museum of Natural History (A.M.
No. 6115/1) there is another specimen of this species (PI.
32, fig. 3). It is an external mold of a left valve, and the
museum label accompanying the specimen describes it as
“Matrix of Type.” Hall figured only one left valve (1883
and 1884b, pl. 32, fig. 22) and this specimen may have
originally covered that left valve. It is listed as being from
the same locality as Hall’s other materials and shows mul-
tiple costae.
At the United States National Museum (No. 68055)
there is a plastotype of the specimen used by Hall for his
figure 21, plate 32 (1883 and 1884b); this plastotype is
herein figured on Plate 32, figure 5. The museum label ac-
companying the plastotype noted that the original was at
the Walker Museum (No. 10900), however, the original
could not be located in time to be figured herein, as the
Walker Museum Collections were being transferred to the
Chicago Natural History Museum; the plastotype indicates
that the original was a poorly preserved right valve.
Williams and Kindle (1905, pp. 118 and 125) listed
Byssopteria radiata as occurring at two different localities
in Tioga County, Pennsylvania (northcentral Pennsyl-
vania) in rocks of Chemung age. Their notations of oc-
currence appear in faunal lists, however, the specimens
which they identified as B. radiata are at the United States
~I
National Museum and are figured herein (PI. 32, figs. 4
and 6). These specimens are similar to the lectotype of B.
radiata and are herein regarded as belonging to the same
species.
Byssopteria occidentalis Fenton and Fenton, 1924
This species is not known to exhibit costal multiplica-
tion and it may or may not belong to Byssopteria. It is from
the Hackberry Stage (Late Devonian) of Iowa.
Byssopteria semiplana Frech, 1891
This form is from the German Devonian. On the basis
of Frech’s figures it does not appear to belong to Byssop-
teria.
Byssopteria? sp. Reed, 1904
This form is from the Bokkeveld (Devonian) Beds of
South Africa and probably does not belong to the genus.
Byssopteria? sp. Talent, 1963
Remarks and comparisons.—On_ the lectotype of
Byssopteria radiata the umbo is carinate and the costae
decrease markedly in width in the posterodorsal part of
the shell (PI. 32, fig. 7) . The plastoparalectotype also shows
umbonal carination, however, the costae in the posterodor-
sal part of the shell are not well preserved (PI. 32, fig. 5).
Williams and Kindle’s specimens (PI. 32, figs. 4, 6) do not
show prominent umbonal carination, but they do show the
decrease in width of the posterodorsal costae.
There seems to be no set pattern of costal multiplica-
tion in Byssopteria radiata, intercalated costae are few in
number (PI. 47, fig. 2) ; not all of the primary costae bifur-
cate (PI. 47, fig. 4); some of the costae trifurcate (Pl. 47,
fig. 2) ; and in some specimens the costae in the posterodor-
sal part of the shell are more or less fascicled (PI. 32, fig. 7).
In general the costal multiplication seems to be rather hap-
hazard; in part this may be because none of the known
specimens of B. radiata are well preserved and not all of
the costae can be traced from the upper umbo to the young-
est edge of the shell.
Hall (1884b, p. xiv) described the genus as having a
nasute projection in front, and his figure of the lectotype
(1883 and 1885, pl. 80, fig. 11) shows a prominent antero-
dorsal projection. However, this feature is not present on
the lectotype (Pl. 32, fig. 7); there is an area of matrix
here which gives the appearance of a projection, but it is
not part of the specimen. Also in 1884b, Hall described the
type species as being subequivalved; because no bivalved
specimens of the genus are known this cannot be corrobora-
ted. For the same reason Miller’s (1889) description of the
176 PALAEONTOGRAPHICA AMERICANA (V, 36)
valves as equal cannot be verified. ‘Thus, the genus can be
assigned only questionably to the family.
Compared to other multiple ribbed North American
forms Byssopteria differs from Opisthoptera Meek in lack-
ing a posterior wing and in having costae rather than
costellae. In Maryonychia, n. g. the primary costae regularly
bifurcate, there is no umbonal carination, and the genus is
known to have a well-developed byssal gape.
Genus CLEIONYCHIA Ulrich, 1892
Plates 32-34
1847. [2] Ambonychia Hall, Nat. Hist. New York, Palaeont. of New
York, vol. 1, p. 315; [non] Ambonychia, pp. 163 and 292.
1861. Ambonychia Hall [partim], Geol. Sur. Wisconsin, Rep. of
Progress, p. 31.
1892. Cleionychia Ulrich, The American Geologist, vol. 10, p. 97.
1892. Clionychia Ulrich, Miller, ist Appendix to North American
Geol. and Palaeont., p. 699.
1893 (1895). [2] Clionychia Ulrich, Geol. Sur. Ohio, Rep., vol. 7,
Oa0s
1894. Giieiehta Ulrich, Lower Sil. Lamellibranchiata of Minnesota,
from Final Rep., Geol. and Nat. Hist. Sur. Minnesota, vol. 3, p.
493. [Published under separate cover prior to the entire vol. 35]|
1895. Ambonychia Hall [partim], Whitfield, American Mus. Nat.
Hist., Mem., vol. 1, part 2, p. 57.
1897. Clionychia Ulrich, Geol. and Nat. Hist. Sur. Minnesota, Final
Rep., vol. 3, part 2, Paleont., p. 493. [This is a reprinting of
the 1894 paper. ]
1900. Clionychia Ulrich, Dall, in Zittel-Eastman, Textbook of Paleont.,
vol. 1, p. 368. [1st ed.]
1908. Clionychia Ulrich, Cumings, Dept. Geol. and Nat. Resources
Indiana, 32d Ann. Rep., p. 979.
1909. Clionychia Ulrich, Grabau and Shimer, North American Index
Fossils, vol. 1, p. 435.
1910. [2] Ambonychia Hall [partim], Hind, Roy. Soc. Edinburgh,
Trans., vol. 47, part 3, p. 488.
1913. Clionychia Ulrich, Dall, in Zittel-Eastman, Textbook of Paleont.,
2d ed., vol. 1, p. 445.
1916. Clionychia Ulrich, Raymond, Carnegie Mus., Annals, vol. 10,
p. 334.
1934. [?] Clionychia Ulrich, Kobayashi, Faculty of Sci., Imperial
Univ. of Tokyo, Jour., vol. 3, sec. 2, part 8, p. 352.
1941. [?] Clionychia [Ulrich], Butts, Virginia Geol. Sur., Bull. 52,
part 2, pp. 73 and 128.
1944. Clionychia Ulrich, Shimer and Shrock, Index Fossils of North
America, p. 387.
1952. [?] Clionychia [Ulrich], Reed, Roy. Irish Acad., Proc., vol.
55, sec. B, No. 3, p. 76.
1956. Clionychia Ulrich, Wilson, Canada Dept. Mines and Tech.
Surs., Geol. Sur. Canada, Bull. 28, p. 59.
1958. Clionychia Ulrich, Khalfin, Akademiya Nauk SSSR, Trudy
Geologicheskogo Instituta, Vypusk 9, p. 170.
1960. Clionychia Ulrich, Soot-Ryen, H. and Soot-Ryen, T., Norsk
Geologisk Tidsskrift, vol. 40, part 2, p. 105.
Type species.—Ambonychia lamellosa Hall, 1862 (p.
437), by original designation of Ulrich, 1892 (p. 97).
Originally proposed as Ambonyc hia cancellosa Hall, 1861
(p. 31).
Diagnosis. — Ambonychiidae with concentric prosopon
only, length usually slightly more than height, angle gamma
90 degrees or less, and with posterior musculature in pos-
terodorsal part of the shell.
Description. — Shell equivalved, inequilateral, lacking
an anterior lobe; beaks prosogyral and terminal; prosopon
of concentric growth varices and in some species concentric
undulations, no radial prosopon; shell completely un-
known; size small to medium; byssal sinus more or less
prominent; no discernible byssal gape; angle gamma, 90
degrees or less (not known to be more than 90 degrees) ;
length and height subequal, no forms known in which
height is greater than the length.
Ligamental area and dental structures completely un-
known; posterior adductor muscle scar in posterodorsal
part of shell, anterior adductor scar unknown, such a muscle
was presumably present because of the position of the pos-
terior adductor scar; remnants of posterior byssal-pedal re-
tractor scar present above the posterior adductor scar, an-
terior byssal retractor usually with one large origin in the
shell, occasionally bifid, with a smaller anterior origin and
a larger posterior one; pallial line doubtfully known in one
specimen.
Synonymic discussion. — Ulrich (1892) proposed this
genus for Middle Ordovician forms with concentric proso-
pon; as originally proposed the generic name was spelled
Cleionychia. Ulrich used the name four times in 1892 and
each time it was spelled Cleconychia; thus, this was the
original intended spelling of the name. S. A. Miller (1892,
p. 699) was the first author subsequent to Ulrich to use the
generic name and he spelled it Clionychia; Miller gave no
reason for the change in the spelling of the name.
According to the International Code of Zoological
Nomenclature (1964, p. 35, Art. 32, sec. a) :
The original spelling of a name is to be retained as the “correct
original spelling’, unless
(i) it contravenes a mandatory provision of Articles 26 to 31; or
(ii) there is in the original publication clear evidence of an
inadvertent error, such as a lapsus calami, or a copyist’s or
printer’s error (incorrect transliteration, improper latinization,
and use of an inappropriate connecting vowel are not to be
considered inadvertent errors) ; or
(iii) in the case of a family-group name, .. .
Cleionychia does not contradict any mandatory pro-
visions of Articles 26 to 31 of the Code, and as Ulrich used
the same spelling four times in the original publication
there is no indication of any sort of an inadvertent spelling
error.
Ulrich (1892, p. 97) gave the etymology of the name
Cleionychia as: “Cleio, I close, onyx, a claw;” while Miller
(1892, p. 699) gave the etymology of Clionychia as: “kleio,
I close; onyx, a claw.” Apparently the correct latinization of
the Greek verb kleio (to close) is cli-, not cleio-. Jaeger
(1955, p. 60) listed the Latin prefix cli- as being derived
from the Greek verb kleio (to shut) or the past participle
NorTH AMERICAN AMBONYCHIIDAE: POJETA
kleistos (shut or closed) as in Di-cli-ptera. On p. 59 Jaeger
listed the Latin prefix clei- as coming from the Greek
kleis (a key) as in Cleio-crinus.
Thus, Ulrich proposed the name Cleionychia on an in-
correct latinization of the Greek; however, as indicated in
the Code, Article 32, section a, part ii this is not to be con-
sidered an inadvertent error and, thus, must stand as pro-
posed.
Article 33 of the Code (p. 37) reads as follows:
Subsequent spelling.—
(a) Emendations.—Any demonstrably intentional change in the
original spelling of a name is an “emendation”.
(i) A “justified emendation” is the correction of an incorrect
original spelling and the name thus emended takes the
date and authorship of the original spelling.
(ii) Any other emendation is an “unjustified emendation’’; the
name thus emended has status in nomenclature with its own
date and author, and is a junior objective synnonym [sic]
of the name in its original form.
(b) Incorrect subsequent spellings——Any change in the spelling of
a name, other than an emendation, is an “incorrect subsequent
spelling”; it has no status in nomenclature and therefore does
not enter into homonymy and cannot be used as a replacement
name.
The spelling change from Cleionychia to Clionychia
is either an “unjustified emendation” or an “incorrect sub-
sequent spelling.” Although Miller (1892) and subsequent
authors who referred to the genus used the spelling Cliony-
chia (including Ulrich, 1893 (1895) and 1894), no author
explains why he resorted to the spelling change. Apparently
the various authors (in particular Miller, who first used the
changed spelling) felt that the incorrect Latinization would
be noted, and that no further explanation was necessary.
If Clionychia is regarded as an “unjustified emenda-
tion” it assumes status in nomenclature as Clionychia Mil-
ler, 1892 and becomes a junior objective synonym of
Cleionychia Ulrich, 1892. If this is accepted, then the two
names fall under section b of Article 25 (Law of Priority)
of the Code (p. 23) which reads: “A name that has re-
mained unused as a senior synonym in the primary zoo-
logical literature for more than fifty years is to be consid-
ered a forgotten name (nomen oblitum).” If the name is
considered to be an “incorrect subsequent spelling” it has
no nomenclatural status and Cleionychia Ulrich, 1892 is the
correct spelling, author, and date of the name.
Because no author explains the spelling change from
Cleionychia to Clionychia it need not be regarded as an
intentional change, but may be considered to be the per-
petuation of an “incorrect subsequent spelling.” In addi-
tion, because Ulrich is the obvious author of the generic
name and concept (not Miller), and because the nomen
oblitum proposal is highly controversial (and it is doubtful
177
that section b of Article 23 was intended to be applied in
cases such as this) the spelling change to Clionychia is here-
in regarded as an “incorrect subsequent spelling,” and UL
rich’s original spelling of the generic name is used.
Hind (1910) referred a specimen found in the Ordovi-
cian (Llandeilian) of Girvan, Scotland to Ambonychia
undata (Emmons). The specimen he figured is similar to
the American species which is now placed in Cleionychia.
However, Hind’s identifications of various species of am-
bonychiids need confirmation.
Kobayashi’s (1954) assignment of a Middle Ordovician
Korean species to this genus is based on one specimen in
which the prosopon seems to be only poorly known for he
described the surface as being smooth. As mentioned pre-
viously his specimen seems to be an ambonychiid.
Of the materials referred to this genus by Butts (1941)
from the Middle Ordovician of Virginia, several specimens
exhibit both concentric undulations and growth lines,
and several of them also have remnant anterior lobes. No
other Middle Ordovician North American forms are known
which combine concentric prosopon and an anterior lobe;
Butts’ materials may belong to one of Isberg’s Scandinavian
genera.
The materials assigned to this genus by Reed (1952)
from the Irish Ordovician are poorly illustrated, and how
he distinguished between Ambonychinia Isberg, 1934 and
Cleionychia Ulrich, 1892 is uncertain. Reed (1952, p. 74)
suggested that the name Ambonychinia Isbere be used for
forms with concentric prosopon, however, Ulrich (1892)
had already segregated North American forms with only
concentric prosopon in Cleionychia. In addition, Isberg’s
primary taxobasis for Ambonychinia was an edentulous
hinge line, and the species he included in the genus had a
variety of prosoponal types. This problem has already been
discussed under the genus Ambonychiopsis (p. 160) where
it was concluded that before the synonymies of the concen-
trically marked genera could be properly established the
morphology of the North American forms would have to be
better known, as they bear the older generic names.
Soot-Ryen and Soot-Ryen assigned their Norwegian
material to two species of Cleionychia, C. undata (Em-
mons) and Cleionychia species A. Only the former need be
considered here, and their specimen of this species is similar
to North American materials.
Lastly, the type species of this genus, Ambonychia
lamellosa Hall, 1862, was originally proposed as A. cancel-
losa Hall (1861, p. 31). However, Hall (1862, p. 437) ina
catalog of the fossils of Wisconsin gave the name of this
species as: “A. lamellosa, Hall, Geol. Report Wisconsin,
178 PALAEONTOGRAPHICA AMERICANA (V, 36)
1861, p. 3
to Ambonychia on page 31, and Hall apparently intended
’ 4. cancellosa is the only species assigned
to change the name from A. cancellosa to A. lamellosa.
Whitfield (1882, p. 205 and 1895, p. 57) and Bassler
(1915, p. 241) noted that the name 4. cancellosa was an
error and that Hall meant to call the species A. lamellosa.
Whitfield (1895, p. 57) in a footnote wrote: “The name of
this species [Ambonychia lamellosa] was originally printed
A. cancellosa, by typographical error, but is corrected in the
margin of my copy of the Report of Progress [ Hall, 1861]
to A. lamellosa.” Although Hall did not publish a state-
ment to the effect that cancellosa was a typographical error
for lamellosa, the fact that he changed the name to lamellosa
is his 1862 Catalog while at the same time giving a refer-
ence to his 1861 Wisconsin Report, is sufficient evidence
that lamellosa was intended as a valid emendation of can-
cellosa. No author since Hall (1861) has used A. cancellosa
and the biomen 4. lamellosa is herein regarded as the cor-
rect name of the species.
Materials. —'The above description is based solely upon
type materials; the author had Hall’s, Ulrich’s, and Butts’
original specimens at his disposal.
Distribution. — In North America this genus has been
reported from the Middle and Late Ordovician, and one
Silurian species was temporarily assigned here before being
subsequently placed in Mytilarca.
Outside of North America the genus may occur in the
Ordovician of Korea, Ireland, Sweden, and Kazakastan,
U.S.S.R.; it is probably found in the Middle Ordovician
rocks of Norway and Scotland.
SPECIES LISTING
From the Upper Ordovician and the Silurian of North
America the following species have been placed in Cleiony-
chia.
“Cleionychia angusta” Foerste, 1918
Plate 29, figures 7-9
This species is herein reassigned to the genus Anoptera
Ulrich and has already been discussed herein. It is from
the Richmondian (Late Ordovician) of Michigan.
Cleionychia subundata Ulrich, 1893 (1895)
Plate 32, figures 8, 9
This species was described from the uppermost Cyn-
thiana rocks of northern Kentucky. It is based upon poor
material and it is doubtful that the generic assignment of
the types can be accurately determined. It seems best to
limit the name to the type material.
Cleionychia excavata Ulrich, 1893 (1895)
Plate 32, figures 10-12
This species was described from the Richmondian of
Indiana. Ulrich’s figures notwithstanding, it is based on
one poorly preserved and highly weathered specimen; its
generic assignment cannot be determined, and it is doubtful
if any other specimen could be considered conspecific with
the holotype. ‘This name too will probably have to be
limited to the type specimen.
Cleionychia (?) superba (Billings), 1866
Ulrich (1892) suggested that this Gamachian (Late
Ordovician) species might belong to Cleionychia, and
Twenhofel (1928) questionably assigned the species to this
genus. ‘Twenhofel mentioned that the generic assignment
of the species is uncertain and that it looks much like an
Allonychia; unfortunately, he does not figure the species.
Billings’ original figures show a large form with concentric
prosopon, and he mentioned the presence of a rudimentary
anterior wing. The species is larger than any other assigned
to Cleionychia, and it probably does not belong to that
genus.
Ambonychia nitida Billings, 1866
Ulrich (1892) suggested that this Niagaran (Middle
Silurian) species might belong to Cleionychia, but in 1894
he was uncertain as to the proper generic assignment.
Twenhofel (1928) reassigned the species to Mytilarca Hall
and Whitfield.
The following North American Middle Ordovician
forms have been assigned to Cleionychia.
Cleionychia curta Foerste, 1924
C. curta is a small poorly known species from the Late
Ordovician (Lorraine) of Quebec. It is described as having
concentric undulations and growth lines, and it may belong
to this genus.
As indicated above, all six post-Middle Ordovician
North American species which have been placed in
Cleionychia are poorly known; at best they can be only
questionably placed in the genus.
Cleionychia erecta (Hall), 1861
Plate 33, figures 18-22, 25
This species was regarded as Trentonian (Late Middle
Ordovician) in age by Hall (1861) and Ulrich (1894), but
Bassler (1915) and the museum label accompanying UI-
rich’s hypotype listed it as occurring in the Blackriveran
NorTH AMERICAN AMBONYCHIIDAE: POJETA 179
(Middle Middle Ordovician). Hall’s syntypes are from
Wisconsin and Ulrich’s hypotype is from Minnesota.
Of Hall's original syntypic series (A.M. No. 931/1)
the specimen herein figured on Plate 33, figures 18-20 is
chosen as the lectotype of the species. Of the other two
| specimens one bears the number A.M. 731/1 and is not an
ambonychiid; the second (PI. 35, fig. 25) is regarded as a
paralectotype of the species (A.M. No. 9351/1).
Whitfield (1895) regarded this species as a subjective
synonym of C. lamellosa. Ulrich (1894) mentioned a few
slight differences in form between the two species; however,
these could not be objectively applied by all describers.
The two names are probably synonyms.
Cleionychia (?) gibbosa Whiteaves, 1908
This species was questionably assigned to the genus by
Whiteaves; it is from rocks of Blackriveran age (Middle
Middle Ordovician) in Ontario.
Cleionychia lameilosa (Hall), 1862
Plate 33, figures 1-17
C. lamellosa was described by Hall (1861, as Ambony-
chia cancellosa) and Ulrich (1892) as Trentonian (Late
Middle Ordovician) in age, however, Bassler (1915) and
the museum labels of Ulrich’s hypotypes list it as occurring
in rocks of Blackriveran age (Middle Middle Ordovician)
in Wisconsin and Minnesota. Foerste (1920) reported the
species as occurring in the Auburn Chert (Trentonian) of
Missouri.
Hall’s original syntypic suite consists of five specimens;
the specimen figured herein on Plate 33, figures 1-3 is
chosen as the lectotype (A.M. No. 929 /2) . Its measurements
are: length, 36 mm.; height, 31 mm.; thickness, 8 mm.; and
diagonal dimension, 39 mm. The other four specimens are
regarded as paralectotypes (A.M. No. 92972).
Probably the species designations C. erecta (Hall) and
C. nitida Ulrich are synonymous with C. lamellosa (Hall) .
Bekker (1921) assigned an Estonian specimen to this
species, however, Opik (1930) placed this specimen in
Ahtioconuha.
Cleionychia marginalis Raymond, 1905
This species occurs in the Lower Chazyan rocks (Early
Middle Ordovician) of northern New York State.
Cleionychia montrealensis (Billings), 1859
C. montrealensis was originally placed in Vanuxemia
Billings (a cyrtodontid) and was subsequently placed in
Cleionychia by Whiteaves (1908); this latter assignment
was confirmed by Raymond (1916). The species has been
reported from Middle and Upper Chazyan rocks (Early
Middle Ordovician) of upstate New York and adjacent
parts of Quebec, Canada.
Cleionychia mytiloides (Hall), 1847
Plate 34, figure 12
This species was placed in this genus by Ulrich
(1892) . Hall’s holotype is a small poorly preserved specimen
(A.M. No. 536/1), and it may in reality belong to one of
the other better known Chazyan species. It is from the
Chazy Limestone (Early Middle Ordovician) , Chazy, New
York. ‘This species name may have to be limited to the type
material.
Cleionychia nitida Ulrich, 1894
Plate 33, figures 23, 24
According to Bassler (1915) this species is from the
Blackriveran rocks (Middle Middle Ordovician) of Min-
nesota; Ulrich (1894) listed it as being Trentonian (Late
Middle Ordovician) in age.
Of Ulrich’s original two syntypes (M.G.S. No. 5099)
the specimen herein figured on Plate 33, figures 23, 24 is
chosen as the lectotype. Its measurements are: length, 19
mim.; height, 19 mm.; thickness, 6.5 mm.; and diagonal di-
mension, 24 mm. Probably Whitfield (1895) was correct
in synonymizing this name with Cleionychia lamellosa.
This species should not be confused with Mytilarca
nitida (Billings) from the Niagaran. Ulrich (1892) first
suggested that Billings’ species might belong to Cilevony-
chia. In 1894 he wrote that the exact systematic position of
Billings’ species was uncertain and erected a new species
based on specimens from the Blackriveran rocks (Middle
Middle Ordovician) of Minnesota for which he proposed
the new name Cleionychia nitida.
Ulrich expressed some doubt about separating this
species from C. lamellosa but suggested that it differed
somewhat in slight variations of the external shape and in
having more numerous growth lines.
Cleionychia ottawaensis Whiteaves, 1908
Whiteaves proposed this species name for shells from
the Blackriveran rocks (Middle Middle Ordovician) of
Ontario, Canada.
Cleionychia rhomboidea Ulrich, 1892
Plate 34, figures 9-11
This is a Blackriveran (Middle Middle Ordovician)
species from Minnesota with an angle gamma of about 70
180 PALAEONTOGRAPHICA AMERICANA (V, 36)
degrees; however, the prosopon is poorly known and the
proper generic assignment is uncertain. The holotype 1s
housed at the Minnesota Geological Survey (M.G.S. No.
5526) .
Cleionychia triangularis Raasch in Shrock and Rasch, 1937
In the original description only a single valve of this
species was illustrated. In general shell shape C. triangularis
is close to C. lamellosa.
Cleionychia undata (Emmons), 1842
Plate 34, figures 1-5
C. undata is a form with prominent concentric undula-
tions and an almost quadrangular shape. However, concen-
tric growth lines are not known in the species.
Emmons holotype could not be located, and Ulrich’s
hypotype (U.S.N.M. No. 46119) is not well preserved
(Pl. 34, figs. 4, 5). Hall’s 1847 hypotype (N.Y.S.M. No.
2307) preserves the concentric undulations very well (PI.
34, figs. 1-3) and has the following dimensions: length, 31
mm.; height, 26 mm.; thickness, 9 mm.; and diagonal di-
mension, 37 mm. The species is from the Trentonian (Late
Middle Ordovician) of Minnesota, New York, and On-
tario.
This species (or forms close to it) also occurs in the
Middle Ordovician of Scotland (Hind, 1910) and Norway
(Soot-Ryen and Soot-Ryen, 1960), and in the Ordovician
of Kazakastan, U.S.S.R. (Khalfin, 1958).
Wilson’s 1956 specimens of C. undata are well pre-
served and are the only North American specimens of the
species figured since Ulrich (1897) .
Cleionychia attenuata (Hall), 1861
Plate 34, figures 6-8
This species was assigned to Cleionychia by Ulrich
(1892) ; Ulrich (1894) changed the assignment and placed
it in synonymy with C. lamellosa (Hall). In his original
syntypic series Hall had two specimens (A.M. No. 930/1),
one of which is largely rebuilt with plaster of Paris and is
not figured herein; the other specimen is figured on Plate
34, figures 6-8 and was chosen as the lectotype of the species
by Shrock and Raasch (1937, p. 557) .
The lectotype has concentric undulations and a much
smaller angle gamma than Cleionychia lamellosa. In addi-
tion, this specimen preserves at least remnants of an antero-
dorsal projection (PI. 34, fig. 7). It is doubtful that the
species name is synonymous with C. lamellosa.
Hall’s original specimen is listed as coming from the
Trenton limestone (Upper Middle Ordovician) of Wis-
consin, but Bassler (1915) listed the species as coming
from rocks of Blackriveran age (Middle Middle Ordovi-
cian) in Wisconsin.
Cleionychia attenuata may belong to Ambonychiopsis,
but until specimens are found with costellae this cannot be
determined with certainty.
Ulrich (1892) assigned Ambonychiopsis amygdalina
(Hall) to Cleionychia, but in 1894 decided this assignment
was in error, and that the species belonged to Ambonychi-
opsis. As mentioned above this species name may be synony-
mous with 4. orbicularis (Emmons) .
NON-NORTH AMERICAN SPECIES
Cleionychia crebra Khalfin, 1958
This species has the general appearance of other forms assigned
to Cleionychia; C. crebra occurs in the Ordovician of Kazakastan,
U.S:S.R.
Cleionychia crispa Khalfin, 1958
This species has the general aspect of C. undata Emmons. C.
crispa is from the Ordovician of Kazakastan, U.S.S.R.
Cleionychia oviformis Kobayashi, 1934
This species is from the Middle Ordovician of South
Korea; as mentioned above its generic assignment needs
confirmation.
Cleionychia subovalis Reed, 1952; C. swbquadrata
Reed, 1952; and C. transversa (Portlock), 1843 are de-
scribed by Reed (1952) from the Ordovician of Tyrone
County, Ireland. As mentioned above better materials and
photographs of these species are needed before their gen-
eric assignment can be corroborated.
Remarks and comparisons. — Ulrich (1894, p. 493) de-
scribed details of the morphology of this genus which could
not be noted on any of the type materials by the present
author. Ulrich described the genus as being edentulous and
as having a ligamental area which was excavated longi-
tudinally for a linear ligament, but his materials do not
show these features. Likewise, his description of the pallial
line as: “simple, extending from the posterior adductor to
the rostral cavity” is not supported by the materials. He
figured the posterior byssal-pedal retractor scar of this genus
as being large, larger than in any other genus of the family
(1894, pl. 55, figs. 10 and 19); the materials that were
available to Ulrich show only remnants of this muscle scar
(Pl. 33, fig. 22; Pl. 54, fig. 10) and do not warrant his inter-
pretation.
Because the posterior adductor muscle of this genus
is situated in the posterodorsal part of the shell, there
probably was a small anterior adductor muscle, even though
there is no anterior lobe and no anterior muscle scar is
NortTH AMERICAN AMBONYCHIIDAE: POJETA 181
known. Pelecypods which possess only a posterior adductor
muscle usually have it located subcentrally in the valves.
Among modern Mytilaceans, which are heteromyarian, the
posterior adductor is still located in the posterodorsal part
of the shell and a small anterior adductor is present.
It is difficult to tell members of this genus from those
of Mytilarca Hall and Whitfield and Anoptera Ulrich.
None of these genera is morphologically well known, all
lack an anterior lobe, and all have only concentric proso-
pon. Unfortunately, the details of morphology which are
known in one genus are unknown in the others and com-
parisons are difficult to make. Generally speaking, My-
tilarca is obliquely elongate with the height greater than
the length; while in Cleconychia these dimensions are sub-
equal with the length being a little greater than the height,
and Cleionychia tends to be more quadrangular. Anoptera
also has the height greater than the length, and is composed
of erect forms with a prominent byssal sinus.
Genus CONGERIOMORPHA Stoyanow, 1948
1948. Congeriomorpha Stoyanow, Jour. Paleont., vol. 22, No. 6, p.
784.
Type species.—Congeriomorpha andrusovi Stoyanow,
1948 (p. 786), by original designation.
Diagnosis. — Ambonychiidae with concentric prosopon,
anterior lobe, umbonal septum, and prominent byssal gape.
Description. — Shell inequilateral, with a small anterior
lobe, nonalate posteriorly; beaks prosogyral, terminal;
prosopon of concentric growth varices; shell known only
from silicified materials and structure uncertain; byssal
gape below the anterior lobe, wide, up to 10 mm. long;
byssal sinus more or less prominent; size medium to large.
Ligamental area and posterior musculature unknown;
cardinal dentition unknown, posterior lateral dentition
composed of one tooth in the left valve, and probably two
teeth in the right valve; umbonal septum present, crossed
by an oblique ridge.
Species listing and distribution. — So far as known only
one species is assigned to the genus, Congeriomorpha
andrusovi Stoyanow; it has been identified only from the
Late Devonian (Chemung) Island Mesa beds of north-
central Arizona.
Remarks and comparisons. — The above description is
based upon Stoyanow’s 1948 paper; only one poorly pre-
served specimen of the genus was seen by the author.
Stoyanow noted (p. 787) that the left valve is probably
less inflated than the right, which would make the genus
inequivalved; however, on page 786 in speaking of his single
bivalved specimen he wrote: “Of the eight illustrated speci-
mens the syntype No. IMB. | . consists of both valves
which were collected together in the matrix but not in
juxtaposition . . .” Apparently this means that Stoyanow
regarded the two valves as belonging to a single individual,
although they were not found articulated. Additionally, the
right valve which he figured appears to be deformed, and
there seems to be no reason to assume that the genus was
inequivalved. By the same token, until a nondeformed
specimen showing the two valves in juxtaposition is found
it cannot be demonstrated that the genus is equivalved.
This latter condition appears to be the more likely one, for
the genus is ambonychiid in other respects.
Stoyanow chose no holotype for the type species. How-
ever, because I have not seen the original materials of
Congeriomorpha andrusovi 1 have deferred choosing a
lectotype.
Genus ECTENOPTERA Ulrich, 1894
1894. Ectenoptera Ulrich [nomen nudum], Lower Sil. Lamellibran-
chiata of Minnesota, from Final Rep., Geol. and Nat. Hist. Sur.
Minnesota, vol. 3, p. +85. [Published under separate cover prior
to the entire vol. 3.]
1897. Ectenoptera Ulrich [nomen nudum], Geol. and Nat. Hist. Sur.
Minnesota, Final Rep., vol. 3, part 2, Paleont., p. 485. [This is
a reprinting of the 1894 paper above.]
This generic name was never formally proposed by
Ulrich, although it appears in the listing of the genera
which he assigned to the family in 1894 and 1897, and he
credited the name to himself. In the Errata for the 1894 and
1897 papers (p. 628) Ulrich noted the following: “Page
485. . . for Ectenoptera, Ulrich read Opisthoptera, Meek.”
Ulrich was rather displeased with the somewhat informal
way in which Meek had proposed Opisthoptera (Ulrich
1893 (1895), p. 642), and apparently originally thought of
substituting Ectenoptera for Opisthoptera.
Genus ERIDONYCHIA Ulrich, 1893 (1895)
Plate 34, 35
1894. Eridonychia Ulrich, [nomen nudum], Lower Sil. Lamellibran-
chiata of Minnesota, from Final Rep., Geol. and Nat. Hist. Sur.
Minnesota, vol. 3, p. +98. [Published under separate cover prior
to the entire vol. 3.]
1893 (1895). Eridonychia Ulrich, Geol. Sur. Ohio, Rep., vol. 7, p. 639.
1897. Eridonychia Ulrich, Geol. and Nat. Hist. Sur. Minnesota, Final
Rep., vol. 3, part 2, Paleont., p. 498. [This is a reprinting of the
1894 paper above. ]
1908. Eridonychia Ulrich, Cumings, Dept. Geol. and Nat. Resources
Indiana, 32d Ann. Rep., p. 980.
Type species.—Eridonychia apicalis Ulrich, 1893
(1895) (p. 639), by original designation.
Discussion. — This genus was defined by Ulrich (1893
(1895) , p. 639) as being: “Like Byssonychia [Ambonychia]
and Anomalodonta, excepting that the hinge is edentulous.”
182 PALAKONTOGRAPHICA AMERICANA (V, 36)
His taxobasis for Eridonychia could be debated, for
Anomalodonta has only one poorly developed cardinal
tooth; however, none of the specimens assigned to Evidony-
chia by Ulrich show the hinge line.
Ulrich (1893 (1895) ) assigned three species to this
genus based upon a total of four specimens. Two of his
specimens are external casts and the other two are external
molds; none of them are well preserved.
The holotype and only specimen of the type species
Eridonychia apicalis (U.S.N.M. No. 46198) is herein fig-
ured on Plate 34, figures 13-14. It is a poorly preserved ex-
ternal mold on which about 15 costae can be counted, and
it may have had as many as 30 as Ulrich suggested. The
museum label lists the specimen as coming from the
Fairmount member of the Fairview formation (Maysville) .
The obliquely elongate character of the shell, its estimated
number of costae, and its angle gamma of about 90 degrees
suggest that it is a poorly preserved specimen of Ambony-
chia acutirostris (Ulrich). This is consistent with its strati-
graphic position; A. acutirostris is known from the Fair-
mount member in the Tristate Area of Ohio, Indiana, and
Kentucky.
Ulrich (1893 (1895), p. 639) commented on the simi-
larity of Eridonychia apicalis to Ambonychia acutirostris:
This species resembles Byssonychia [Ambonychia] acutirostris very
closely, and collectors will no doubt find it difficult to separate them
when the specimens are not very good. A careful comparison shows
that the margin of the byssal opening is more sharply inflected and
the beaks, especially in casts, more erect in the Eridonychia. The
principal differences however lie in the hinge, that species [dm-
bonychia acutirostris| having true cardinal teeth and a narrower
ligamental area...
The hinge line of Eridonychia apicalis is unknown and
that of Ambonychia acutirostris is poorly known; the other
distinctions suggested by Ulrich could be attributed to the
poorly preserved condition of the holotype and only known
specimen of Eridonychia apicalis. Therefore, Eridonychia
apicalis Ulrich is herein regarded as a junior synonym of
Ambonychia acutirostris (Ulrich).
The second species assigned to this genus by Ulrich
was Eridonychia paucicostata Ulrich, 1893 (1895) (Pl. 34,
figs. 15, 16) . This species is supposed to differ from the type
species in having only 17-18 costae, otherwise, Ulrich said
they were similar. E. paucicostata is based upon two speci-
mens, the holotype and a paratype (U.S.N.M. No. 46200) .
Nothing of the hinge line is preserved in this species and,
if anything, the specimens upon which it is based are more
poorly preserved than is the holotype of E. apicalis. E.
paucicostata is also from the Fairmount member of the
Fairview formation, and has the general obliquely elongate
nature and angle gamma of Ambonychia acutirostris. How
many costae may have been present originally is conjectural,
and this species too is regarded as a junior synonym of 4.
acutirostris.
The third species assigned to the genus by Ulrich was
Eridonychia crenata (PI. 35, fig. 1). This is based upon
one external mold where no hinge line structures are ob-
servable (U.S.N.M. No. 46199). The museum label notes
that it is from the Richmond Waynesville formation. The
holotype preserves about 20 costae and this takes in most of
the shell, probably it did not have more than 30 costae at
a maximum and perhaps fewer; Ulrich estimated about 23.
His specific taxobasis was that the edge of the shell is not
smooth but crenulated. ‘The proper placement of this species
is for the time being uncertain; there is no reason to include
it in a special genus (Eridonychia), particularly when the
primary taxobasis used to separate Eridonychia from other
genera cannot be demonstrated in the species.
Thus, the genus Eridonychia Ulrich is not recognized
herein. Two of its species, &. paucicostata and the type
species E. apicalis, are placed in synonymy with Ambony-
chia acutirostris. At the moment the proper placement of
the third species, Eridonychia crenata, cannot be deter-
mined. It may represent a distinct morphological form,
however, it probably belongs to Ambonychia or Anomalo-
donta.
Genus GOSSELETIA Barrois, 1882
Plate 35, 36
1882. Gosseletia Barrois, Societé Géologique du Nord, Mém., tome 2,
Nos Ly ps 273.
1883. [non] Gosseletia de Koninck, Musée Royal d’Histoire Naturelle
de Belgique, Annales, tome 8, p. 28.
1883. Gosselettia [Gosseletia| Barrois, Hall, Nat. Hist. New York,
Geol. Sur. New York, Palaeont., vol. 5, part 1, Lamellibranchiata
Plates and Explanations, p. 4.
1884. Gosselettia | Gosseletia] Barrois, Hall, New York State Cab.
Nat. Hist., 35th Ann. Rep., pp. 405 and 406d.
1884. Gosselettia [Gosseletia] Barrois, Hall, Geol. Sur. New York,
Palaeont., vol. 5, part 1, Lamellibranchia 1, pp. xiv and 265.
1885. Gosseletia Barrois [partim], Follmann, Verhandlungen des
naturhistorischen Vereines der preussischen Rheinlande, West-
falens und des Reg.-Bezirks Osnabrick, vol. 42, Verhandlungen,
p. 207; Sitzungsberichte, p. 77.
1886. Gosseletia Barrois, Fischer, Manuel de Conchyliologie, p. 963.
1889. Gosselettia [Gosseletia] Barrois, Miller, North American Geol.
and Palaeont., p. 482.
1891. Cyrtodontopsis Frech [partim], Abhandlungen zur geologischen
Specialkarte von Preussen und den Thiiringischen Staaten, band
9, Heft 3, p. 125.
1899. Gosselettia [Gosseletia] Barrois, Grabau, Buffalo Soc. Nat.
Scis., Bull., vol. 6, p. 249.
1900. Gosseletia Barrois, Dall, im Zittel-Eastman, Textbook of Paleont.,
vol. 1, p. 368. [1st ed.]
1910. [Non] Gosseletia Barrois, Hind, Roy. Soc. Edinburgh, Trans.,
vol. 47, part 3, p. 500.
1913. Gosseletia Barrois, Dall, in Zittel-Eastman, Textbook of
Paleont., vol. 1, p. 445. [2d ed.]
1913. [Non] Gosselletia | Gosseletia| Barrois, Clarke and Swartz,
Maryland Geol. Sur., Middle and Upper Devonian, p. 641.
1920. Gosseletia Barrois [partim], Maillieux, Société Belge de
|
.
NortH AMERICAN AMBONYCHIIDAE: POJETA 183
Géologie, de Paléontologie et d’Hydrologie, Bull., tome 29
(1919), p. 144.
1937. Gosseletia Barrois [partim], Maillieux, Musée Royal d'Histoire
Naturelle de Belgique, Mém. No. 81, p. 86.
1944. Gosselettia [Gosseletia| Barrois, Shimer and Shrock, Index
Fossils of North America, p. 387.
1950. [Non] Gosseletia Barrois, LaRocque, Univ. Michigan, Mus. of
Paleont., Contrib., vol. 7, No. 10, p. 293.
1952. Gosseletia Barrois, Dechaseaux, in
Paléont., tome 2, p. 266.
Piveteau, Traité de
Type species. — Gosseletia devonica Barrois, 1882 (p.
274) , by subsequent designation of Mallieux, 1957 (p. 86) ;
? Follmann, 1885b, p. 208.
Diagnosis. — Ambonychiidae with anterior lobe, con-
centric prosopon, well-developed cardinal and lateral denti-
tion, and lacking a discernible byssal gape.
Description. — Shell equivalved, inequilateral, with an
anterior lobe, nonalate; beaks nonterminal, prosogyral;
prosopon of concentric growth lines only; no discernible
byssal gape; wide ligamental space; size medium to large.
Ligamental area possessing duplivincular grooves and
ridges; pallial line poorly known, described as simple (in-
tegropalliate?) ; adductor scar
poorly known, described as large and faint, anterior ad-
heteromyarian, posterior
ductor scar in anterior lobe; other musculature unknown;
dentition consisting of well-developed cardinal and lateral
teeth, the former usually three in number with the anterior-
most often bifid.
Synonymic discussion. — Barrois proposed the name
Gosseletia for a Devonian ambonychiid from Spain in 1882.
In the following year De Koninck used the same name for
a genus of gastropods; Fischer (1885) subsequently replaced
Gosseletia de Koninck by Gosseletina.
Hind’s 1910 materials show no anterior lobe, their
dentition is unknown, and one of the specimens he assigned
to the genus appears to be a modiolopsid.
or
LaRocque (1950) quoted Maillieux’s (1957
tion of the genus and assigned one specimen to Gosseletia.
However, this specimen shows no anterior lobe and prob-
ably does not belong to Gosseletia.
descrip-
Frech (1891) proposed the name Cyrtodontopsis as a
subgenus of Gosseletia. Maillieux (1937, p. 96) discussed
the four species Frech had placed in Cyrtodontopsis and
came to the following conclusions: C. kayseri Frech and C.
quartzitica Frech belong to Cyrtodonta Billings; Cyrtodon-
topsis praecursor Frech belongs to Modiomorpha Hall and
Whitfield; Cyrtodontopsis halfari is probably a species of
Gosseletia. Thus, Maillieux disbanded Cyrtodontopsis.
Maillieux (1920) subdivided Gosseletia into two sub-
genera; he proposed that all forms with concentric prosopon
only be placed in Gosseletia (Gosseletia) , and placed those
species with radial prosopon in the new subgenus Gosseletia
(Stappersella) . Herein Stappersella is regarded as a distinct
genus. Drevermann (1907)
pseudalectryonia Frech as the type species of the new genus
Follmannia.
used the species Gosseletia
Beginning with Hall (1883), most American authors
have misspelled the name Gosseletia as Gosselettia. How-
ever, LaRocque (1950) returned to the spelling proposed
by Barrois.
Materials. —'The only specimens of this genus available
to the author were Hall’s 1883 and 1884a and b type ma-
terials, and several weathered new specimens; otherwise, the
above description is based upon the literature. The North
American forms placed in Gosselctia are similar to the
European species placed in the genus, and Gosseletia is one
of the few ambonychiid genera definitely known to occur in
both Europe and North America.
Distribution. — As far as known Gosseletia is limited to
the Devonian rocks of western Europe and eastern North
America. In Europe where numerous species have been
named, the genus is known from Spain, the Ardennes region,
and Germany where it occurs primarily in the Early Deyon-
ian. In North America the genus has been reported from
the Middle Devonian of Manitoba, Canada (Whiteaves,
1892, p. 293) and Michigan, New York, and Ohio.
NORTH AMERICAN SPECIES
As far as known to the author, in North America only
the two species described by Hall (1885 and 1884a and b)
have been placed in Gosseletia.
Gosseletia triquetra (Conrad), 1838
Plate 35, figures 2-4, 8-18; Plate 36, figures 1-4
Gosseletia retusa Hall, 1883
Remarks and comparisons. — Gosseletia triquetra was
originally assigned to Ptcrinca by Conrad, 1838. His defini-
tion is minimal, however, Hall (1883 and 1884b) located
what he thought to be Conrad’s holotype (A.M. No.
5274/1). This specimen was figured by Hall on plate 31,
figure 10 and is herein figured on Plate 35, figures 8-10.
The holotype is well preserved and only slightly distorted;
its measurements are: length, 43 mm.; height, 51 mm.;
thickness of a single valve, 20 mm.; diagonal dimension, 52
mm.; and angle gamma, 73 degrees. There are two speci-
mens at the American Museum with the above number
(5274/1); Hall (1885 and 1884b) figured both of these but
mentioned only the specimen herein figured on Plate 35,
figures 8-10 as Conrad’s presumed original. The second
184 PALAEONTOGRAPHICA AMERICANA (V, 36)
specimen (Hall, pl. 31, fig. 9; not figured herein) is ap-
parently one collected by Hall. The beak and very upper
part of the right umbo of the holotype are reconstructed
in wax, but this does not effect the value of the specimen.
All of Hall’s materials are from the Hamilton rocks of
New York. At the United States National Museum there are
specimens of Gosseletia from Hamilton Drift in Michigan,
and Shimer and Shrock (1944) listed Gosseletia triquetra as
occurring in rocks of Middle Devonian age in Michigan,
New York, and Ohio.
I have not been able to locate Hall’s types of G. retusa.
The specimen illustrated by Hall has a shell shape which
differs from that of G. triquetra, however, nothing is known
of the dental structures of G. retusa.
Genus LOPHONYCHIA Pohl, 1929
Plate 36
1911. Mytilarca Hall [and Whitfield] [partim], Cleland, Wisconsin
Geol. and Nat. Hist. Sur., Bull. 21, Scientific Series No. 6, p. 108.
1929. Lophonychia Pohl, [partim], Public Mus. City of Milwaukee,
Bull., vol. 11, No. 1, p. 48.
Type species.—Mytilarca trigonaic Cleland, 1911 (p.
108), by original designation of Pohl, 1929 (pe 49)E as
Lophonychia trigonale (Cleland) .
Diagnosis. — Costellate (?) _Ambonychiidae with pos-
terior adductor muscle scar located in the posterocentral
part of the valve.
Description. — Shell inequilateral, lacking an anterior
lobe, nonalate; beaks terminal and prosogyral; prosopon
probably of simple costellae; shell completely unknown;
byssal sinus shallow; there may be a small discernible byssal
gape; length and height about equal; only known species is
small in size.
All internal features except the posterior adductor
muscle unknown; the latter is unusually located for the
family, being at about the middle of the height, but near
the posterior margin.
Species listing and distribution. —As far as known to
the author there is only one species presently assignable to
the genus, L. trigonaie (Cleland), 1911. It has been identi-
fied only from the Lower Middle Devonian Lake Church
formation of Wisconsin.
Remarks and comparisons. — LaRocque (1950, p. 294)
suggested that Lophonychia Pohl might be synonymous with
Gosseletia Barrois; this proposal is not herein followed be-
cause Lophonychia lacks an anterior lobe, and at least in
the holotype appears to possess costellate prosopon.
Pohl in erecting the genus described the hinge line as
having small cardinal and lateral teeth and as being longi-
tudinally excavated for a linear ligament (1929, p. 48) ; on
page 49 he mentioned that there is an “apparent lack of
teeth” in the genus. The type material of L. trigonale shows
nothing of the ligamental or dental structures; herein, the
dentition and ligament type are regarded as unknown.
The specimen figured on Plate 36, figures 5-8 is chosen
as the lectotype of L. trigonale (Cleland). Cleland (1911)
based this species upon two syntypes (U.S.N.M. Nos, 80288
and 142821), and Pohl (1929) refigured the syntypes but
chose no lectotype. The measurements of the lectotype are:
length, 17 mm.; height, 15 mm.; width, 5 mm.; and diagonal
dimension, 18 mm. Cleland’s other specimen is figured on
Plate 36, figures 9-10 and is regarded as a paralectotype of
the species.
The lectotype of the type species preserves what appear
to be remnants of costellae in the region posterior and
ventral to the posterior adductor scar (PI. 36, figs. 5, 8).
Radial prosopon among Devonian ambonychiids occurs in
only three other genera: Follmannia Drevermann and Stap-
persella Maillieux are known only from Eurasia, while the
multicostate genus Byssopteria Hall is from the Late Devon-
ian of North America. Lophonychia is distinct in having
what appears to be a simplicicostellate condition and an
unusually placed posterior adductor muscle scar. ‘The an-
terior face of the lectotype (Pl. 36, fig. 7) shows what
seems to be a small discernible byssal gape. Because no bi-
valved specimens of the genus are known, it cannot be de-
termined whether or not Lophonychia is equivalved.
Pohl (1929), in addition to placing L. trigonale in this
genus, erected the new species Lophonychia cultellata. The
type materials of this species show no sign of costellate pro-
sopon, nor of the posterior adductor scar; in addition, they
appear to have been strongly distorted. The only feature
which the two species have in common is carination of the
umbones; this is a recurrent feature among ambonychiids
occurring in Ambonychia, Opisthoptera, Byssopteria, and
other genera, and of itself does not constitute a valid gen-
eric taxobasis. Lophonychia cultellata is herein regarded as
being based upon distorted material probably of some
species of Mytilarca. Species of this latter genus possess
only concentric prosopon and occur throughout the Devon-
ian. :
Stewart (1933, p. 178) proposed the new species Lopho-
nychia cordata. This is a large, concentrically marked, cari-
nate form similar to L. cultellata Pohl. For the same reasons
discussed under the latter species the generic assignment
of L. cordata must be considered tentative.
NortH AMERICAN AMBONYCHIIDAE: POJETA 185
Genus MARYONYCHIA Pojeta, new genus
Plate 36
1872. [Non] Opisthoptera Meek, Acad. Nat. Sci. Philadelphia, Proc.
for 1871, part 3, p. 319.
1910. Opisthoptera Foerste, Sci. Labs. Denison Univ., Bull., vol. 16,
p. 70.
Type species.—Opisthoptera concordensis — Foerste,
1910 (p. 70), is herein designated the type species of the
new genus Maryonychia.
Diagnosis. — Multicostate Ambonychiidae with a prom-
inent byssal gape and lacking a posterior alation.
Description. — Shell inequilateral, lacking an anterior
lobe and a posterior wing; beaks terminal, prosogyral;
obliquity prosocline; prosopon of growth varices and multi-
ple costae, the latter consisting of primary costae which
bifurcate (Pl. 36, fig. 11); between each pair of secondary
costae there is usually a single intercalated costa (PI. 56,
fig. 15), although there are sometimes two intercalated
costae; only the outer costate shell layer is known; byssal
sinus shallow; byssal gape prominent; size medium to
large.
Internal features unknown, except for ligamental
remnants in one specimen.
Species listing and distribution. —Only one species is
presently assigned to the genus, Maryonychia concordensis
(Foerste) , 1910. This species is limited to the Arnheim and
Waynesville formations (Late Ordovician) of the Tristate
Area of Ohio, Indiana, and Kentucky.
Remarks and comparisons.— The genus is named for
my wife, Mary Louise.
While the internal features of the genus are largely
unknown, it is a distinct type differing from Opisthoptera
in lacking a posterior wing and in having costae not
costellae. Maryonychia differs from Byssopteria in the
regularity of its costal subdivision, in lacking umbonal
carination, and in the known presence of a byssal gape.
Undoubtedly the reason why Foerste placed Maryony-
chia concordensis in Opisthoptera was because of the multi-
ribbed condition; however, the two genera differ signifi-
cantly in their rib patterns and in wing development.
SPECIES DESCRIPTION
Maryonychia concordensis (Foerste), 1910
Plate 36, figures 11-15
1910. Opisthoptera concordensis Foerste, Sci. Labs. Denison Univ.,
Bull voll 16.sps 70) pla Ll, figs 9:
Diagnosis. — At present this is the only species assigned
to Maryonychia; it has 20-25 primary costae and an angle
gamma of 80-90 degrees.
Description.—Shell quadrate; with 20-25 primary
costae which bifurcate, although not necessarily at the same
distance from the peaks of the umbones; as far as known
each costa bifurcates only once forming two secondary
costae; between bifurcated costae there is usually one inter-
calated costa, however, occasionally there are two intercal-
ated costae between secondary costae; angle gamma, 80-90
degrees; umbones rounded, not keeled; thickness of a single
valve, up to 20 mm.; byssal gape fusiform, up to 10 mm.
long, and located about its length below the umbonal
peaks; byssal sinus shallow; size medium to large.
Internal features unknown, except for ligamental
remnants in one specimen.
Types and materials — The above desc ription is based
upon Foerste’s holotype (U.S.N.M. No. 84803) of the
species and five additional specimens, two of which are
figured herein.
The dimensions of the holotype are as follows: length,
60 mm.; height, 65 plus mm.; thickness, 15 mm.; diagonal
dimension, 72 plus mm.; angle gamma, 90 degrees; and
primary costae, 19 plus.
Distribution.—The species distribution is the same as
that of the genus.
Genus MEGAPTERA Meek and Worthen, 1866
This is an invalid objective senior synonym of Opis-
thoptera Meek, 1872; see that genus for a discussion of the
generic name Megaptera.
Genus MYTILARCA Hall and Whitfield, 1869
Plates 37-42
1869. Mytilarca [Hall and Whitfield] [partim], Preliminary Notice
of the Lamellibranchiate Shells of the Upper Helderberg,
Hamilton and Chemung Groups, with Others from the
Waverly Sandstones, part 2, p. 19.
Mytilarca (Hall and Whitfield] [partim], Preliminary Notice
. Sandstones, part 2, p. 19. [This is an expanded version of
the 1869 paper above, however, the Mytilarca portion remained
the same in both works.]
Mytilarca [Hall and Whitfield], Hall, New York State Cab.
Nat. Hist., 23d Ann. Rep., pl. 14, figs. 11-13. [No text.]
Plethomytilus Hall, Nat. Hist. New York, Geol. Sur. New York,
Palaeont., vol. 5, part 1, Lamellibranchiata Plates and Explana-
tions, p. 4.
Mytilarca [Hall and Whitfield] [partim], Hall, Nat. Hist. New
York, Geol. Sur. New York, Palaeont., vol. 5, part 1, Lamelli-
branchiata Plates and Explanations, pls. 32, 33, and 80. [No
text. |
Mytilarca Hall [and Whitfield], Hall, New York State Cab.
Nat. Hist., 35th Ann. Rep., pp. 401 and 406d.
Mytilarca s. g. Plethomytilus Hall, New York State Cab. Nat.
Hist.. 35th Ann. Rep., pp. 401 and 406d.
Mytilarca Hall [and Whitfield] [partim], Hall, Geol. Sur. New
York, Palaeont., vol. 5, part 1, Lamellibranchiata 1, pp. xiv and
253.
1870.
186 PALAEONTOGRAPHICA AMERICANA (V, 36)
1884. Mytilarca sub-genus Plethomytilus Hall, Geol. Sur. New York,
Palaeont., vol. 5, part 1, Lamellibranchiata 1, pp. xiv and 253.
1886. Mytilarca Hall [and Whitfield], Fischer, Manuel de Conchylio-
logie, p. 963.
1889. Mytilarca Hall [and Whitfield] [fartim], Miller, North Ameri-
can Geol. and Palaeont., p. 493.
1889. Plethomytilus Hall, Miller, North American Geol. and Palaeont.,
De) 503:
1891. Moalize de Koninck [partim], Frech, Abhandlungen zur geolo-
gischen Specialkarte von Preussen und den Thiiringischen
Staaten, band 9, Heft 3, p. 139.
1896. [Non] Mytilarca [Hall anl Whitfield], Miller and Gurley,
Illinois State Mus. Nat. Hist., Bull. 11, p. 14.
1899. Plethomytilus Hall, Grabau, Buffalo Soc. Nat. Scis., Bull., vol.
6, p. 248.
1904. Streptomytilus Kindle and Breger, Dept. Geol. and Nat. Re-
sources Indiana, 28th Ann. Rep., p. +52.
1908. [2] Mytilarca Hall [and Whitfield], Chapman, Nat. Mus. Mel-
bourne, Mem. 2, p. 44
1909. Mytilarca Hall [and Whitfield] [partim], Grabau and Shimer,
North American Index Fossils, vol. 1, p. 432.
1909. Plethomytilus Hall, Grabau and Shimer, North American
Index Fossils, vol. 1, p. 433.
1910. [2] Mytilarca Hall [and Whitfield], Hind, Roy. Soc. Edin-
burgh, Trans., vol. 47, part 3, p. 516.
1930, Mytilarca [Hall and Whitfield] [partim], Caster, Bull. Ameri-
can Paleont., vol. 15, No. 58, p. 71. rE
1934. [?] Mytilarca Hall [and Whitfield], Isberg, Studien Uber
Lamellibranchiaten des Leptaenakalkes in Dalarna, p. 107.
1937. Plethomytilus Hall, Maillieux, Musée Royal d'Histoire Naturelle
de Belgique, Mém. No. 81, p. 81.
1937. Mytilarca Hall [and Whitfield], Maillieux, Musée Royal
d'Histoire Naturelle de Belgique, Mém. No. 81, p. 84.
1944. Mytilarca Hall [and Whitfield] [partim], Shimer and Shrock,
Index Fossils of North America, p. 387.
1944. Plethomytilus Hall, Shimer and Shrock, Index Fossils of North
America, p. 387.
1952. [Non] Mytilarca Hall [and Whitfield], Moore, Lalicker, and
Fischer, Invertebrate Fossils, p. 420.
1958. [?] Mytilarca Hall [and Whitfield], Khalfin, Akademiya Nauk
SSSR, Trudy Geologicheskogo Instituta, Vypusk 9, p. 172.
1962. Mytilarca Hall and Whitfield, McAlester, Peabody Mus. Nat.
Hist., Yale Univ., Bull. 16, p. 38.
Type species. —Inoceramus chemungensis Conrad,
1842 (p. 246), by original designation of Hall and Whit-
field, 1869 (p. 20), as Mytilarca chemungensis (Conrad) .
Diagnosis. —Dentate Ambonychiidae with concentric
prosopon and lacking a discernible byssal gape.
Description. — Shell equivalved, inequilateral, lacking
an anterior lobe and a posterior wing; beaks terminal and
prosogyral; prosopon of concentric growth lines only; byssal
sinus weak to well developed; no discernible byssal gape;
shell poorly known; size small to large.
Ligamental area with numerous fine duplivincular
grooves and ridges; pallial line unknown, other muscula-
ture unknown; hinge line with posterior lateral teeth and
with cardinal teeth; as far as known the posterior lateral
teeth mounted on what is either a posterior shell thickening
or a posterior vertical lamella.
Synonymic discussion.—When the name Mytilarca
was originally proposed (December, 1869) it was published
anonymously. In January, 1870 an expanded version of the
1869 paper was published, and inserted in front of the
first page of this work (1870) was a slip of paper which
read “With the Compliments of James Hall.” On the basis
of this most workers accepted Hall as the author of the
generic name Mytilarca. However, Cooper (1931) showed
that in reality Hall and Whitfield were coauthors of the
1869 and 1870 papers. Of the numerous references to the
generic name only McAlester (1962) noted the coauthor-
ship of Mytilarca.
As discussed previously, the primary generic taxobasis
for the separation of the genus Streptomytilus from other
ambonychiids is not herein considered to be valid; because
most of the species assigned to Streptomytilus were formerly
placed in Mytilarca, they are returned to this genus.
Hall (1883) proposed Plethomytilus as a new genus
and placed several species formerly assigned to Mytilarca
and one new species in Plethomytilus. On page 4 Hall dis-
tinguished Plethomytilus from Mytilarca as follows: “
Differs from Mytilarca in its true hinge line, and the
absence of teeth .. .” In 1884a (p. 406d) and 1884b (pp.
xiv and 255) Hall reduced Plethomytilus to a subgenus of
Mytilarca, but suggested no adequate distinction between
the two subgenera. Apparently, because of Hall’s 1884a and
b notations that M. (Mytilarca) had both cardinal and
posterior lateral teeth while M. (Plethomytilus) was only
known to have lateral teeth, subsequent authors have used
this as the taxobasis for separating Hall’s two subgenera
and have treated each subgenus as a genus in its own right.
While both “genera” are known to have posterior
lateral teeth (Pl. 38, figs. 4, 14; Pl. 41, fig. 4) the anterior
end of the hinge line has not been observed in well-preserved
specimens of any species assigned to Plethomytilus. Of Hall's
1883-84 materials only one specimen of Mytilarca chemun-
gensis preserves what may be remnants of the cardinal den-
tition (Pl. 38, fig. 4). This specimen shows one or two
obscure grooves below the anterior end of the ligamental
area which may be molds of cardinal teeth. Whether or not
these are the same grooves which Hall considered to be
cardinal teeth is uncertain; he illustrated three cardinal
teeth which he showed as crossing the ligamental grooves
and ridges (1883-84, pl. 33, fig. 8). The only specimens of
Mytilarca with well-preserved cardinal and posterior lateral
teeth which I have seen belong to an unnamed species of
the genus (U.S.N.M. No. 101593) from the Late Silurian
Edmunds formation of Maine G2E Si, ike, il, 2).
One other distinction between the two ‘
that most species of Plethomytilus are larger than most
species of Mytilarca. However, this is not an absolute cri-
‘genera’ is
terion of separation and, in any case, size would make a
NortTH AMERICAN AMBONYCHIIDAE: POJETA 187
poor generic taxobasis when unsupported by other distinc-
tions.
The two generic names are herein considered to be
synonyms; in the present state of knowledge they cannot
be separated by any tangible objective criterion. As these
forms become better known they may have to be separated,
but at the moment there is no way to distinguish species
assigned to one genus from those assigned to the other.
Testimony to this is that subsequent to Hall species were
assigned arbitrarily to one genus or the other even though
their dental structures were completely unknown.
Isberg (1934) assigned 12 new species from the Ordo-
vician Leptaena limestone to Mytilarca. These forms have
concentric prosopon and several of them are figured show-
ing both cardinal and posterior lateral dentition mounted
on separate vertical lamellae. His Swedish forms may be
congeneric with North American Mytilarcas. However, no
North American species of Mytilarca are known from Or-
dovician rocks, and the dentition of North American con-
centrically marked Ordovician genera is not known.
Distribution.—In North America Mytilarca has been
reported from all Silurian and Devonian series. Many of
these identifications must be considered as tentative, pend-
ing the finding of better materials. Geographically most
species assigned to the genus occur in the northeastern quar-
ter of the United States and adjacent parts of Canada, al-
though Mytilarca is doubtfully identified from Nevada
(Walcott, 1884) and Colorado (Girty, 1900 and Kindle,
1909) .
In Europe the genus has been reported from the
Leptaena limestone (Ordovician) of Dalarna, Sweden (Is-
berg, 1934); from the Silurian of Scotland (Hind, 1910) ;
and Poland (Korejwo and Teller, 1964); and from the
Devonian of the Ardennes area (Maillieux, 1957) , Germany
(Frech, 1891), and Siberia (Khalfin, 1940) .
At least three probable Mississippian species have been
assigned to Mytilarca: M. occidentalis (White and Whit-
field) (Pl. 39, fig. 12), M. fibristriata (White and Whit-
field) (Pl. 39, figs. 13-15), and M. jessieae Miller and
Gurley (PI. 39, figs. 16-19). These are oblique species with
a definite mytiliform aspect and probably belong to the
Mytilidae or to the Modiolopsidae. The ligamental type of
these species is unknown, but the general shape of the shell
is not ambonychiid. All three species are similar to the
Late Paleozoic Mytilidae described by Newell (1942). Be-
cause of the former inclusion of these Mississippian forms
in Mytilarca, many of the references cited in the above
synonymy refer to Mytilarca only in part. Branson (1938)
placed M. jessieae in the genus Prothyris Meek.
NORTH AMERICAN SPECIES
No attempt is made herein to assort the numerous
species assigned to this genus from North America. This
would be a separate study in itself, and much more would
be needed in the way of material to determine which species
are valid. Numerous type specimens of Mytilarca species
are herein photographically illustrated for the first time,
and in a number of instances comments are made about the
various species on the basis of the type materials. McAlester
(1962) has restudied the Mytilarcas of the Chemung Stage
of New York, and I have followed his listing of Chemung
species.
SILURIAN SPECIES
Mytilarca acutirostra (Hall), 1865
Plate 37, figures 1-7
Hall in the 1865 Advance Printing (discussed above
under the genus Amphicoclia) tentatively placed this form
in Ambonychia. Ulrich (1894, p. 494) placed the species in
Mytilarca and was followed in this by Clarke and Ruede-
mann (1903, p. 48). The holotype (PI. 37, figs. 1-3) is from
the Niagaran (Middle Silurian) of Wisconsin (A.M. No.
1951/2) ; it shows no concentric prosopon and preserves no
dental features, thus, it can be assigned only questionably to
Mytilarca. In addition, the specimen shows a discernible
byssal gape; this is an unusual feature in post-Ordovician
ambonychiids. Similar forms at the United States National
Museum (PI. 37, figs. 5-7) from the Niagaran rocks of
Illinois and Indiana do not show a discernible byssal gape.
The specimen figured on Plate 37, figure 4 (N.Y.S.M.
No. 2822) was described by Hall (1882, p. 314) from the
Niagaran of Indiana and was regarded by him as being con-
specific with Ambonychia acutirostra. This hypotype is
poorly preserved and prepared, and it is doubtful that it
can be specifically identified.
Mytilarca amii McLearn, 1924
McLearn figured one specimen which shows concentric
prosopon; it is from the Stonehouse formation (Late Silur-
ian) of Nova Scotia, Canada.
Mytilarca aphaea (Hall), 1865
Plate 40, figures 10-12
This species was also described in Hall’s 1865 Advance
Printing; it is based upon one specimen (A.M. No. 2068/1)
which preserves nothing of the dental structures nor of the
prosopon, and it was placed in the genus Streptomytilus by
Kindle and Breger.
188 PALAEONTOGRAPHICA AMERICANA (V, 36)
Mytilarca cuneatus (Kindle and Breger), 1904
Plate 40, figures 5-6
This species is based upon one specimen from the
Niagaran (Middle Silurian) — of (holotype,
U.S.N.M. No. 62321). The prosopon is unknown, and it
Indiana
may possess remnants of posterior lateral teeth. It was
originally assigned to Piethomytilus, however, the reason
for this assignment was not discussed. In view of the lack
of knowledge of the prosopon the species may not belong to
Mytilarca, but until new materials are found this cannot
be determined.
Mytilarca eduliformis Clarke and Ruedemann, 1903
Plate 38, figures 7-8
The species is based upon one poorly preserved partial
specimen with some remnants of concentric prosopon
(N.Y.S.M. No. 9131). Originally placed in Mytilarca by
Clarke and Ruedemann; it was subsequently placed in
Streptomytilus by Kindle and Breger (1904). Mytilarca
(Middle Silurian) of
New York State, but it is poorly preserved and the name
eduliformis is from the Niagaran
will probably have to be limited to the holotype.
Mytilarca foerstei Clarke and Ruedemann, 1903
Plate 37, figure 20
The species is based upon a single partially shelled
specimen which shows concentric prosopon (U.S.N.M. No.
88537) . The species was described from the Medinan (Early
Silurian) Brassfield limestone of Ohio as Mytilarca mytili-
formis by Foerste (1893 (1895) ). He was uncertain as to
the generic assignment and followed Ulrich’s advice that it
belonged to Mytilarca. However, at the same time Foerste
was describing Mytilarca mytiliformis as a new species of
Mytilarca (1893 (1895), p. 559) he included a quotation
from a personal communication with Ulrich (p. 560) which
placed Myalina mytiliformis Hall, 1852 in Mytiiarca. Thus,
in effect he placed two species with the same trivial name
in Mytilarca. Clarke and Ruedemann (1903) noted this
and renamed M. mytiliformis Foerste, M. foerstei Clarke
and Ruedemann.
Foerste (1893 (1895) ) placed this species in the Clin-
ton (Niagaran) ; however, the museum label notes that it is
from the Brassfield limestone which is regarded as Medinan
(Early Silurian) in age.
Mytilarca nitida (Billings), 1866
This Niagaran (Middle Silurian) species from Que-
bec, Canada, was placed in Mytilarca by ‘Twenhofel (1928) .
Mytilarca mytiliformis (Hall), 1852
M. mytiliformis was originally described as a member
of the genus Myalina but was subsequently placed in My-
tilarca by Ulrich in Foerste (1893 (1895) ), and Clarke and
Ruedemann (1903) accepted this assignment. The species
is from the Niagaran (Middle Silurian) of New York; its
dentition is unknown, but it does have concentric prosopon.
Mytilarca obliqua Weller, 1903
Neither the dentition nor the prosopon of this species
is known; it is from the Late Silurian of New Jersey.
Mytilarca pernoides Whiteaves, 1905
This species is a concentrically marked form from the
Ekwan River region of Ontario, Canada (west side of
James Bay). Whiteaves (1906) described the hinge as hav-
ing both cardinal and lateral teeth but did not figure the
dentition; he also noted that Ulrich thought M. pernoides
was probably a synonym of M. aphaca (Hall). This latter
species was referred to Streptomytilus by Kindle and Breger
(1904) , and Bassler (1915) referred Mytilarca pernoides to
Streptomytilus as a probable synonym of S. aphaea. Myti-
larca pernoides is from the Niagaran (Middle Silurian) of
Ontario, Canada.
Mytilarca sigilla Hall, 1876
Plate 37, figure 19
This species is based upon a small specimen from the
(Middle Silurian)
neither the concentric prosopon nor the dentition (holo-
type, A.M. No. 1948).
Niagaran of Indiana, which shows
Mytilarca wabashensis (Kindle and Breger), 1904
This is the type species of the genus Streptomy tilus
Kindle and Breger. It is a small form from the Niagaran
(Middle Silurian) of Indiana which has concentric proso-
pon, however, the hinge line is unknown.
DEVONIAN SPECIES
Mytilarca chemungensis (Conrad), 1842
Plate 37, figures 8-18; Plate 38, figures 1-5, 10
This species is found in the Chemung and Cassadaga
(Late Devonian) stages of New York and Pennsylvania, and
may also occur in the Late Devonian of Virginia and
Nevada. McAlester (1962) regarded the species names M.
carinata Hall and M. attenuata Hall and Whitfield as sub-
jective synonyms of M. chemungensis (Conrad) .
NortH AMERICAN AMBONYCHIIDAE: POJETA 189
Mytilarca gibbosa Hall, 1884
Plate 39, figure 2
Mytilarca lata Hall, 1883
Plate 39, figure 1
Mytilarca regularis Hall, 1884
Plate 38, figure 21
Mytilarca simplex Hall, 1883
Plate 39, figures 3-4
Mytilarca umbonata Hall, 1883
Plate 38, figures 11-13
The above five species are all from the late Devonian
rocks of New York and Pennsylvania. McAlester (1962) re-
garded them all as being founded upon inadequate ma-
terial and felt that none could be recognized without re-
study.
Mytilarca arenacea Hall and Whitfield, 1869
Plate 40, figures 2-4
This species was described by Hall and Whitfield from
the Schoharie Grit of New York (Early Devonian) and
placed in Plethomytilus by Hall (1883). The species is
based upon two syntypes first figured by Hall in 1883 and
1884b. The specimen herein figured on Plate 40, figures 2, 3
is chosen as the lectotype of the species (N.Y.S.M. No.
2823). The other specimen (A.M. No. 2839) is regarded as
a paralectotype (PI. 40, fig. 4).
Mytilarca canadensis Billings, 1874
M. canadensis is from the Early Devonian of the Gaspé
area of Quebec.
Mytilarca cingulosa Pohl, 1929
Plate 38, figures 19, 20
This species is from the Middle Devonian rocks of
Wisconsin (U.S.N.M. No. 80284) .
Mytilarca cordiformis (Hall), 1859
M. cordiformis was originally placed in Megambonia
by Hall and subsequently assigned to Mytilarca by Hall and
Whitfield (1869). According to Hall (1859b) it is from the
Lower Helderberg group of New York.
Mytilarca cultellata (Pohl), 1929
This species was originally placed in Lophonychia by
Pohl; however, it does not show any radial prosopon, and
the placement of the posterior adductor muscle scar is un-
known.
Mytilarca dalhousei Clarke, 1907
Plate 38, figures 6, 14-17
This species is from the Early Devonian rocks of New
Brunswick, Canada. Clarke’s holotype (N.Y.S.M. No. 8931)
shows the posterior dentition (PI. 38, figs. 14-16) . However,
his (1909) hypotypes (N.Y.S.M. No. 8932; U.S.N.M. No.
56783) are poorly preserved (PI. 38, figs. 6 and 17).
Mytilarca dentata Pohl, 1929
This species is from the Middle Devonian rocks of
Wisconsin.
Mytilarca dubia Walcott, 1884
Plate 40, figure 1
M. dubia was named on the basis of Early Devonian
specimens from Nevada (U.S.N.M. No. 13885) . It is doubt-
ful that this species is a member of the Ambonychiidae.
Mytilarca inflata Whiteaves, 1892
This species is from rocks of Middle Devonian age,
Manitoba, Canada.
Mytilarca knappi Hall, 1884
According to Hall this species is from the Hamilton
(Middle Devonian) of New York; he placed the species in
the subgenus Plethomytilus. The holotype of this species
(P.R-I. No. 6051) was figured by B. Smith (1949) .
Mytilarca marylandica Ohern, 1913
This species is from the Early Devonian of western
Maryland.
Mytilarca mytilimera (Conrad), 1842
M. mytilimera was placed in this genus by Hall and
Whitfield (1869) ; according to these authors it is from the
Lower Helderberg Group of New York.
Mytilarca nitida Billings, 1874
Plate 38, figure 9
The specimen figured herein is Clarke’s 1908 hypotype
of this species (U.S.N.M. No. 56782); it is from the Early
Devonian of the Maritime region of Quebec.
In 1874 Billings described a form by this name from
the Gaspé area of Quebec as a new species. In 1866 Billings
described Ambonychia nitida from the Silurian of Anticosti
Island; the 1866 species was subsequently placed in Myti-
larca by Twenhofel (1928). On the basis of the known
190 PALAEONTOGRAPHICA AMERICANA (V, 36)
figures it is not possible to tell if both of Billings species
belong to Mytilarca.
Mytilarca oviformis (Conrad), 1842
Plate 41, figures 3-4, 7-8; Plate 42, figures 1-6
M. oviformis was placed in Mytilarca by Hall and
Whitfield (1869), and subsequently transferred to Ple-
thomytilus by Hall (1885). Hall gave the Hamilton (Mid-
dle Devonian) of New York as the stratigraphic and geo-
graphic distribution of the species. Several of Hall’s hypo-
types show the posterior dentition and ligamental grooves
and ridges of the species, however, the musculature and
anterior end of the hinge line are still unknown. Five of
Hall’s 1883 and 1884a and b hypotypes are at the American
Museum of Natural History (Nos. 5275/1, 5275/2, 5275/3)
and five other Hall hypotypes are at the New York State
Museum (Nos. 2829-2833) .
Mytilarca percarinata Whitfield, 1882
According to Whitfield (1893 (1895) ), this species is
from rocks of Helderberg age (Lower Devonian) of Ohio.
‘The holotype of this species was figured by Peck and Mc-
Farland (1954).
Mytilarca ponderosa Hall and Whitfield, 1869
Plate 40, figures 7-9, 13-15; Plate 41, figures 1-2, 5-6
This is one of the largest species assigned to the Am-
bonychiidae; it was placed in Plethomytilus by Hall (1883
and 1884b) and is listed as occurring in rocks of Helderberg
age (Lower Devonian) in New York, Ohio, and Ontario.
Of the original syntypic series (A.M. Nos. 3093/3,
3093/4, 3093/5) the specimen herein figured on Plate 41,
figures 1, 2 is chosen as the lectotype of the species (A.M.
No. 3093/3).
Mytilarca pyrimadata Hall, 1883
Plate 38, figures 18, 22-24
The name of this species as spelled above was used by
Hall in 1883; it is probably a typographical error, for in
1884a and b and 1885 Hall spelled the name M. pyramidata.
The species occurs in the Schoharie Grit (Lower Devonian)
of New York.
Mytilarca rowei Ohern, 1913
This species is from the Oriskany formation (Lower
Devonian) of Maryland. Ohern assigned it to the subgenus
Plethomytilus; it may or may not be an ambonychiid.
Mytilarca suberectus (Pohl), 1929
Plate 39, figures 5-11
M. suberectus is from the Middle Devonian rocks of
Wisconsin and was placed in Plethomytilus by Pohl. It
possesses concentric prosopon, but the dentition is un-
known. Pohl illustrated posterior adductor muscle scars on
several syntypes of the species. None of the seven of eight
syntypes (U.S.N.M. Nos. 80227, 142822-142825) seen by me
preserve any of the posterior muscle scars.
Mytilarca trigonale Cleland, 1911
This species was used by Pohl as the type species of
Lophonychia; it appears to be distinct from Mytilarca and
is herein discussed under Lophonychia.
Mytilarca triquetra (Conrad), 1838
This species was placed in Gosseletia by Hall (1883)
and is discussed under that genus.
MISCELLANEOUS SPECIES
Williams and Breger (1916, pp. 213-216) described a
species of Myalina trom the Lower Devonian Chapman
sandstone of Maine. They noted that the species was appar-
ently equivalved but did not feel that it was assignable to
Mytilarca. Some of their figures suggest the species may be
an ambonychiid.
Mytilarca occidentalis, M. fibristriata, and M. jessieae
are three probable Mississippian species which have been
assigned to Mytilarca. As noted above they probably belong
to the Mytilidae or the Modiolopsidae and are not herein
considered to members of Mytilarca. Reed (1931, p. 34)
questionably assigned a Permian pelecypod from Afghan-
istan to Plethomytilus as P. ? plausibilis. Grabau (1936, p.
298) questionably assigned a Chinese Permian pelecypod
to the same genus as P. ? nantanensis. Neither of these
species belongs to Mytilarca.
In addition to the North American species assigned to
this genus and listed above, a number of European species
have been assigned to Mytilarca or to Plethomytilus. Thus,
Isberg (1954) assigned 12 new species to Mytilarca from the
Ordovician rocks of Sweden; Khalfin (1958) described
one new species from the Ordovician rocks of Kazakastan;
Maillieux (1937) described seven species from Lower De-
vonian rocks of the Ardennes area of Belgium, France, and
Luxembourg; Chapman (1908) described a new species
from the Silurian rocks of Victoria, Australia; Hind (1910)
described one species of Plethomytilus from the Upper Or-
dovician and Lower Silurian of Girvan, Scotland; Frech
(1891) described several species of this genus from the
German Devonian; Korejwo and Teller (1964) described
two new species of Mytilarca from the Upper Silurian of
eastern Poland; and Khalfin (1940) described five new
species from the Siberian Devonian. Sherrard (1960) doubt-
fully assigned an unnamed species from New South Wales,
| Australia, to Mytilarca. Her specimen is not well preserved,
and it does not appear to be an ambonychiid. ‘Tolmachoff
(1926) assigned a specimen from the Middle Devonian of
Ellesmere Land to Mytilarca sp. McAlester (1965) placed a
“specimen from the Lower Devonian of Antarctica in My-
tilarca.
Remarks and comparisons.—On the basis of the above
species listing at least 70 specific names have been proposed
for Mytilarcas, and over half of these names have been ap-
plied to North American forms. Undoubtedly there are
additional species names in the literature which have not
been located by me.
It is probable that Mytilarca as used today is both a
“wastebasket” genus and a form genus; it is in approxi-
mately the same taxonomic jumble that Ambonychia was in
prior to Ulrich’s 1892-97 revisions. Unfortunately, there is
no well-preserved material upon which to base a restudy of
Mytilarca as was the case with Ambonychia. The known
specimens of most species of Mytilarca do not preserve mor-
phological details.
Mytilarca is a form genus for all Silurian and Devonian
ambonychiids which have concentric prosopon; and a
“wastebasket’”’ grouping for all those Silurian and Devonian
forms which are founded upon such poor materials that
even the prosopon is unknown.
Attempts at restricting the concept implied by the name
Mytilarca have been only partially successful. Anteriorly
lobed forms have been placed in Gosseletia Barrois; Pohl’s
genus Lophonychia contains costellate forms; McAlester
(1962) has placed two species names is synonymy with M.
chemungensis; and the Mississipian species formerly as-
signed to Mytilarca have been removed herein. However,
these restrictions include only a handful of species (eight
at the most). Attempts to erect the genera Plethomytilus
and Streptomytilus have foundered, because of the lack of
any objective distinctions between these supposed genera
and species which were regarded as still belonging to
Mytilarca. The Silurian species of Mytilarca in particular
are poorly known; most of them are known from a few
specimens which do not even give any knowledge of the
prosopon, much less of the internal features.
Eventually, some way of objectively splitting Mytilarca
into morphologically readily identifiable taxa of equal rank
may be found, and the genus can then be subdivided.
Especially desirable is additional knowledge of the structure
of forms which were given new names for stratigraphic or
geographic reasons, rather than for any discernible morpho-
logical differences from already named species.
NortTH AMERICAN AMBONYCHIIDAE: POJETA 19]
On the other hand, the morphological scheme summed
up by the name Mytilarca may be long ranging in pelecypod
phylogeny. However, until the various species are better
known, it cannot be determined whether or not the mor-
phological scheme was a stable one ranging through a long
period of geological time.
Hall and Whitfield (1869) described the pallial line
and musculature of Mytilarca; none of their materials seen
by the author show any evidence of these structures. In ad-
dition, Hall did not figure any internal features in his
monographs of 1883-85. It may be that Hall and Whitfield
based their description of some of these internal features
upon M. triquetra which was subsequently placed in
Gosseletia.
Genus OPISTHOLOBA Ulrich in Hussey, 1926
1891. [Non] Opistholoba Mik, Wiener Entomologische Zeitung, vol.
10, p. 5.
1926. Opistholoba Ulrich in Hussey, Univ. Michigan, Mus. of Geol.,
Contrib., vol. 2, No. 8, p. 165.
Type species —Opistholoba gouldi Ulrich in Hussey,
1926 (p. 165), by monotypy.
Discussion.—The generic name Opistholoba Ulrich was
proposed in Hussey (1926). No formal description was
given in this work, however, the generic name was credited
to Ulrich and a single species (O. gould’) was described
and. illustrated.
Because the name Opistholoba was first used by Mik
(1891) for a genus of Diptera, it was not available when
Ulrich used it for a genus of pelecypods. Therefore, O pis-
tholoba Ulrich in Hussey, 1926 is a junior homonym of
O pistholoba Mik, 1891 and is invalid. Opistholoba Ulrich is
not herein renamed because the one species assigned to the
genus (QO. gould) is considered to be a member of the
genus Opisthoptera Meek, 1872.
At the United States National Museum there is a
handwritten manuscript of Ulrich’s in which he elaborated
on what he considered to be the pelecypod genus Opistho-
loba; as far as I have been able to determine this manuscript
was never published. In the manuscript Ulrich proposed
five new species of Opistholoba, none of these names were
published, and they have no nomenclatural status. The
specimens upon which Ulrich had planned to base these
five species are housed in the biological collection of
Paleozoic pelecypods at the United States National Mu-
seum. Because Ulrich never published descriptions of these
specimens they have no standing as type materials.
Genus OPISTHOPTERA Meek, 1872
Plates 42-47
1846. [Non] Megaptera Gray, Annals and Magazine Nat. Hist., vol.
17, p. 83.
192 PALAEONTOGRAPHICA AMERICANA (V, 36)
Imbonychia (Megaptera) Meek and Worthen, Chicago Acad.
Sci., Proc., vol. 1, p.22:
1868. Ambonychia subgenus Megaptera Meek and Worthen, Geol.
Sur. Illinois, vol. 3, p. 337. [Reprinting of Meek and Worthen,
1866 above.]
1871. Megaptera Meek and Worthen, Stoliczka, Geol. Sur.
Palaeontologia Indica, Mem., vol. 3, ser. 6, p. 387.
1872. Opisthoptera Meek [partim], Acad. Nat. Sci. Philalelphia, Proc.
for 1871, part 3, p. 319, footnote.
1866.
India,
1873. Opisthoptera Meek [partim], Geol. Sur. Ohio, Rep., vol. 1, part
2, Palaeont., p. 131. [Reprinting of Meek, 1872 above.]
1874. Anomalodonta Miller [partim], Cincinnati Quart. Jour. Sci.
vol. 1, pp. 16 and 224; [won] p. 326.
1874. Megaptera Meek and Worthen [partim], White, American
Jour. Sci. and Arts, vol. 108, p. 218.
1875. Opisthoptera Meek [partim], White, American Jour. Sci. and
Arts, vol. 109, p. 318.
1875. Ambonychia [Hall], Miller, Cincinnati Quart. Jour. Sci., vol.
2, p. 280.
1881. Ambonychia subgenus ? Megaptera Meek and Worthen (O pis-
thoptera Meek), Zittel, Handbach der Palaeontologie, Abt. 1, bd.
2. p. 36.
1893 (1895). Opisthoptera Meek [partim], Ulrich, Geol. Sur. Ohio,
Rep., vol. 7, p. 642.
1894. Ectenoptera Ulrich [nomen nudum], Lower Sil. Lamellibran-
chiata of Minnesota, from Final Rep., Geol. and Nat. Hist. Sur.
Minnesota, vol. 3, p. 485. [Published under separate cover
prior to the entire vol. 3.]
1897. Ectenoptera Ulrich [nomen nudum], Geol. and Nat. Hist. Sur.
Minnesota, Final Rep., vol. 3, part 2, Paleont., p. 485. [This
is a reprinting of the 1894 paper above. |
1908. Opisthoptera Meek [partim], Cumings, Dept. Geol. and Nat.
Resources Indiana, 32d Ann. Rep., p. 982.
1910. [Non] Opisthoptera Foerste, Sci. Labs. Denison Univ., Bull.
vol. 16, p. 70.
1910. [Non] Opisthoptera Meek, Hind, Roy. Soc. Edinburgh, Trans.,
vol. 47, part 3, p. 495.
1926. Opistholoba Ulrich in Hussey, Univ. Michigan, Mus. of Geol.,
Contrib., vol. 2, No. 8, p. 165.
1926. Anomalodonta Miller [partim], Hussey, Univ. Michigan, Mus.
of Geol., Contrib., vol. 2, No. 8, p. 166.
1956. Opisthoptera [Meek], LaRocque and Marple, Ohio Div. Geol.
sur., Bull. 54, p. 51.
Type species—Ambonychia (Megaptera) casei Meek
and Worthen, 1866b (p. 22
Diagnosis.—Multicostellate Ambonychiidae with a well-
, by original designation.
developed posterior wing.
Description.—Shell equivalved, inequilateral, lacking
an anterior lobe, but with a large well-developed posterior
wing; beaks terminal and prosogyral; obliquity prosocline ;
prosopon of concentric growth lines and multiple costellae;
costellate multiplication may be by bifurcation, trifurcation,
or intercalation, and all three types of costellate increase
may occur on the same specimen; shell poorly known;
byssal sinus poorly to moderately well developed; byssal
gape discernible but small; size small to large.
Ligamental areas with duplivincular grooves and
ridges; pallial line integropalliate, attachment discon-
tinuous, areas of attachment closely spaced; posterior
musculature of a large subcentral adductor, dorsal to which
is a small posterior byssal-pedal retractor muscle; in one
species there are small bifid anterior byssal retractor scars;
dentition incompletely known, two named _ species show
posterior lateral teeth and cardinal teeth may be present.
Synonymic discussion.—This genus was originally
named Megaptera by Meek and Worthen (1866b) , and they
considered it to be a subgenus of Ambonychia Hall. Subse-
quently Meek (1872-73) discovered that Megaptera was
preoccupied, having been used by Gray (1846) for a genus
of whales. At that time it had not yet been decided if the
same name could be used more than once in zoology; be-
cause of this uncertainty Meek suggested that if Megaptera
Meek and Worthen proved to be invalid it should be re-
placed by Opisthoptera.
Meek’s proposal of Opisthoptera occurred in a footnote
to the description of the species Ambonychia (Megaptera)
alata. Meek. Ambonychia and Megaptera [Opisthoptera]
are now regarded as separate genera with Ambonychia
alata belonging to Ambonychia; however, Opisthoptera sull
has nomenclatural status for in the proposal to substitute
Opisthoptera for Megaptera, Meek noted that Megaptera
casei Meek and Worthen (the type species of Megaptera)
was to be included under the new name Opisthoptera.
Meek’s footnote reads (1872, p. 320): “. . . If it should be
thought desirable to substitute another name for this group,
as typified by M. [egaptera] Casei and the species here
described [Megaptera alata], 1 would propose to call it
O pisthoptera.”
Meek and Worthen (1866b, p. 22) specifically desig-
nated Megaptera casei as the type species of their taxon
Megaptera: “We consider this curious shell [Megaptera
casei] to be the type of a new subgenus . . .” In addition,
Megaptera casei was the only species assigned to the sub-
genus in 1866b, and if they had not designated it as the
type species, it would have become the type species of
Megaptera by monotypy.
Meek’s replacement of the name Megaptera by Opis-
thoptera was the proposal of a new generic name for an
invalid junior homonym. The fact that the proposal of
Opisthoptera occurred in a footnote to the description of a
species which is no longer placed in Opisthoptera would
seem to have no bearing on the issue, and both Megaptera
Meek and Worthen and Opisthoptera Meek would have the
same type species. The Code is explicit on this point (1964,
p65, At. 16/7, Sec):
If a zoologist proposes a new generic name expressly as a replace-
ment for a prior name, both nominal genera must have the same
type-species, and, ..., type-fixation for either applies also to the
other, despite any statement to the contrary. Example. — B-us
Schmidt, 1890, is proposed expressly as a replacement name for a
junior homonym, 4d-us Medina, 1880, non Dupont, 1860. If x-us is the
designated type-species of d-us, it is ipso facto the type-species of
B-us.
Miller (1874a, p. 16) tentatively assigned Megaptera
|
|
|
‘casei to Anomalodonta Miller. This assignment precipitated
a rather bitter written debate between Miller and White
| (1874-75) as to the proper status and application of the
names Anomalodonta, Megaptera, and Opisthoptera. White
held that because Miller had assigned the type species of
Megaptera (and Opisthoptera) to Anomalodonta the latter
name was invalid, and a synonym of Megaptera. Miller dis-
agreed with this line of reasoning, but he quickly removed
M. casei from Anomalodonta and, at the same time, chose
A. gigantea as the type species of Anomalodonta (1874c,
pp. 331 and 333). Miller's assignment of Megaptera casei
to Anomalodonta was prompted by his opinion that neither
Megaptera nor Opisthoptera were valid names because
neither Meek and Worthen nor Meek had given formal
definitions of the concept behind these names, rather they
had only described species which they regarded as belonging
to Opisthoptera. Because Miller felt that Megaptera and
Opisthoptera were invalid names, this left Magaptera casei
with no generic name and he tentatively assigned it to
Anomalodonta (1874a, p. 16): “. it [Anomalodonta]
will probably include the Megaptera casei (Meek and Wor-
aver) 5g 6”
placement name for Megaptera or Opisthoptera, but merely
Miller did not propose Anomalodonta as a re-
noted that Megaptera casei probably belonged to Anomalo-
donta. He later chose a type species for Anomalodonta
which is distinct from any species assigned to Opisthoptera.
The dispute between Miller and White was in large
part caused by the lack of any generally accepted rules of
nomenclature for American taxonomists during much of
the nineteenth century. If dnomalodonta were the proper
replacement name for Megaptera, then M. casei would have
to be regarded as the type species of Anomalodonta. How-
ever, Opisthoptera is the correct replacement name _ for
Megaptera, and M. casei is the type species of O pisthoptera.
Miller’s assignment of Megaptera casei to Anomalodonta
is not valid as the two genera are distinct; additionally, 4.
gigantea is the type species of Anomalodonta.
Ulrich (1894 and 1897) apparently intended to use
Ectenoptera Ulrich as a replacement name for Opisthop-
tera; however, he never formally proposed Ectenoptera
(see the preceding discussion of the generic name Ectenop-
tera). Ulrich (1893 (1895) ) placed several species which
lack both a wing and multiple costellae in Opisthoptera.
These species are not regarded as belonging to this genus
and are discussed below. Hind (1910) put a lower Silurian
nonalate simplicicostellate form to Opisthoptera; this
species 1s not herein considered to belong to the genus.
Foerste’s 1910 species O. concordensis is herein chosen
as the type species of the new genus Maryonychia. The two
NorTH AMERICAN AMBONYCHIIDAE: POJETA 193
species, Opistholoba gouldi and Anomalodonta griffini,
described in Hussey (1926) possess costellae and posterior
alations, and are transferred to Opisthoptera.
Distribution.—As far as known Opisthoptera is limited
to rocks of Richmond Age (Late Ordovician) in Michigan,
Ontario, and the Tristate Area of Ohio, Indiana, and
Kentucky. It is not known to occur outside of North
America.
Remarks and comparisons—The dentition of O pis-
thoptera is incompletely known. Meek and Worthen
(1866b) described O. casei as having cardinal teeth, how-
ever, they did not figure these and none of my material
shows the anterior end of the hinge line. Three species of
Opisthoptera are known to possess posterior lateral teeth
(Pl. 42, figs. 20, 21; Pl. 44, figs. 7, 13).
Ulrich’s major taxobasis for distinguishing Opis-
thoptera was a long cardinal margin about equal to the
length of the shell (1893 (1895), p. 643) : “The great length
of the hinge line is the character now chiefly relied upon
in distinguishing the genus [Opisthoptera] from Byssony-
chia [Ambonychia], Anomalodonta and Eridonychia.” On
this basis he assigned three simplicicostate nonwinged
species to the genus: “Opisthoptera” laticostata Ulvich
(Pl. 46, fig. 9), “O.” ampla Ulrich (PI. 46, fig. 8), and
“O.” notabilis Ulrich (Pl. 46, figs. 10-11). None of these
species is herein considered to belong to Opisthoptera; they
may belong to Ambonychia Hall, Anomalodonta Miller, or
to a new genus. Only new materials of the three forms can
determine their proper generic assignments.
In addition to the above species, Ulrich (1893 (1895) )
placed five other species from the Tristate Area of Ohio,
Indiana, and Kentucky in Opisthoptera: O. casei (Meek
and Worthen), O. fissicosta (Meek), O. alternata Ulrich,
O. extenuata Ulrich, and O. obliqua Ulvich. Of these five
species only O. casei and O. alternata are herein recognized,
O. fissicosta is tentatively placed in synonymy with O. casei,
whereas O. obliqua and O. extenuata are considered to be
synonyms of O. alternata.
A probable new species of the genus is herein de-
scribed as Opisthoptera species A, and Opistholoba gouldi
Ulrich im Hussey and Anomalodonta griffini Hussey from
the Richmond of Michigan are reassigned to Opisthoptera.
Thus, as herein restricted Opisthoptera has four
named species: O. casei, O. alternata, O. gouldi, and O.
griffint; and a probable new unnamed species: O. sp. A.
SPECIES DESCRIPTIONS
Opisthoptera casei (Meek and Worthen), 1866
Plate 43, figures 1-23; Piate 44, figures 1-4, 10-16; Plate 45, figures
1-6; Plate 46, figure 7; Plate 47, figures 5-8
194 PALAEONTOGRAPHICA AMERICANA (V, 36)
1866. Ambonychia (Megaptera) casei Meek and Worthen, Chicago
Acad. Sci., Proc. vol. 1, p. 22, no fig.
1868. Ambonychia (Megaptera) casei Meek and Worthen, Geol. Sur.
Illinois, vol. 3, p. 337, pl. 4, figs. 9a-b. [Reprinting of Meek and
Worthen, 1866 above.]
1872. Megaptera casei [Meek and Worthen], Meek, Acad. Nat. Sci.
Philadelphia, Proc. for 1871, part 3, p. 320, footnote. [Opistho-
ptera proposed. ]
1873. Megaptera casei [Meek and Worthen], Meek, Geol. Sur. Ohio,
Rep., vol. 1, part 2, Palaeont., p. 131, footnote. [Reprinting of
Meek, 1872 above.]
1873. Ambonychia (Megaptera) casei? Meek and Worthen, Meek,
Geol. Sur. Ohio, Rep., vol. 1, part 2, Palaeont., p. 133, pl. 11,
fig. 8. [Meek suggested that if this form proved to be distinct
it be called 4. fissicosta.]
1874. Anomalodonta casei (Meek and Worthen), Miller, Cincinnati
Quart. Jour. Sci., vol. 1, pp. 16 and 224, no fig. [Paraphrasing
of Meek and Worthen, 1866 above. ]
1880. 4. Megaptera casei Meek and Worthen, White, Indiana Dept.
Statistics and Geol., 2d Ann. Rep., p. 491, pl. 1, figs. 1-2.
[Same description and figures as Meek and Worthen, 1868
above. ]
1893 (1895). Opisthoptera casei Meek and Worthen, Ulrich, Geol.
Sur. Ohio, Rep., vol. 7, p. 643, pl. 49, figs. 1-5.
1893 (1895). Opisthoptera fissicosta Meek, Ulrich, Geol. Sur. Ohio,
Rep., vol. 7, p. 643, pl. 49, fig. 15.
1908. Opisthoptera caset Meek and Worthen, Cumings, Dept. Geol.
and Nat. Resources Indiana, 32d Ann. Rep., p. 1011, pl. 47, figs.
1, la. [Description from Meek and Worthen, 1868; figures
from Ulrich, 1893 (1895).]
1924. [?] Opisthoptera fissicosta (Meek) [partim], Foerste, Canada
Dept. Mines, Geol. Sur., Mem. 138, p. 167, pl. 26, fig. 1; [von]
fig. 2.
1931. [Opisthoptera fissicosta Meek], Moodie, in Jillson, Kentucky
Geol. Sur. Paleont. of Kentucky, p. 12, fig. 5d.
Diagnosis.—O pisthoptera with extensive costellal multi-
plication and an angle gamma of 75-85 degrees.
Description.Shell trigonal with a prominent posterior
wing; prosopon of growth lines and 20-30 primary costellae,
the latter multiply extensively; costellal increase may be by
bifurcation (PI. 47, fig. 8), trifurcation (PI. 47, fig. 6), or
intercalation (P1. 47, fig. 8), and all three types of costellal
multiplication may occur on the same specimen; as far as
known each primary costella subdivides, and the costellae
may be distinctly fascicled or not; angle gamma, 75-85 de-
grees; angle beta, up to 60 degrees, varying with the age
of the individual, it may be as small as 40 degrees in mature
specimens; size small to large; byssal sinus shallow to fairly
well developed; byssal gape small, located about its length
below the umbonal peaks; ligamental areas erect; in molds
there is often a prominent midumbonal keel which is not as
evident in specimens preserving only external features.
Ligamental and posterior musculature as in the generic
description; anterior byssal retractor scars small and bifid;
cardinal dentition may be present, posterior lateral denti-
tion of one or two teeth in each valve.
Synonymic discussion.—The two species names O. casei
and O. fissicosta are herein tentatively placed in synonymy.
Meek (1873, p. 133) gave the following distinctions be-
tween O. casei and O. fissicosta:
In the typical specimens of 4. [Ambonychia] Casei, the costae are
small, and rather closely arranged, or sometimes alternately a little
larger and smaller; while in that here under consideration [Opisthop-
tera fissicosta], they are of nearly the same size as those of the type,
for about one-third to one-half their length, but separated by wider
spaces than their own breadth, after which they bifurcate, or divide
into three, with some other small ones intercalated between, so that
the whole become much smaller near the free margins, though not
exactly equal.
Should this character be found to be constant [enough] .. . to
render it desirable to designate the Cincinnati type by a different
name, it might be called 4. [Ambonychia] fissicosta.
Unfortunately the type material of neither species
could be located. Meek did not note where the type material
of Opisthoptera fissicosta was deposited and White was
the last author who noted the whereabouts of the type
material of O. casei (1880, p. 492): “The figures here given
are copies of those of the type specimens in the private
cabinet of Mr. L. B. Case, of Richmond, Indiana.” I could
not find out what became of the Case Collection.
Specimens more or less corresponding to Meek’s de-
scriptions of the two species are herein figured on Plate 43,
figures 1-4. In forms with the “casei” type prosopon the
costellae are much finer (PI. 44, fig. 3) than in those with
the “fissicosta” type prosopon (PI. 43, fig. 3). However,
both forms have approximately 20-30 primary costellae
which increase in number by subdivision and intercalation,
and both occur throughout the same stratigraphic interval.
Intercalated costellae are more numerous in the “‘fissi-
costa” type than in the “casev’’ type, however, bifurcated
and trifurcated costellae occur in both forms. In addition,
there are specimens whose costellate fineness is intermediate
between that of the “casei” type and that of the “fiss¢costa”
type) (RIA fal x2 Tey 0 seit rs)
On the bases of the intermediate forms and the gen-
eral similarity of the two types, except for costellate fineness,
the two species names are herein tentatively placed in
synonymy pending the finding of Meek’s original materials.
Types and materials.—As mentioned above Meek’s
original type materials could not be located. The author
had at his disposal Ulrich’s 1893 (1895) hypotypic suite
(U.S.N.M. Nos. 46264, 46265, 46267, 142828, 142829) and
a number of new specimens.
Distribution.—The species is limited to the Waynesville
and Whitewater formations of the Tristate Area of Ohio,
Indiana, and Kentucky. Foerste (1924) described a “drift”
specimen from an unknown locality in Ontario which
seems to belong to this species; he assumed a Richmondian
age for this specimen.
Remarks and comparisons.—This species differs from
O. gouldi primarily in lacking the bilobed wing; from O.
eriffint in having a smaller angle gamma; while O. alernata
NorTH AMERICAN AMBONYCHIIDAE: POJETA 195
is much smaller and has an angle gamma of less than 65
degrees.
Opisthoptera alternata Ulrich, 1893 (1895)
Plate 42, figures 7-17
1893 (1895). Opisthoptera alternata Ulrich, Geol. Sur. Ohio, Rep.,
vol. 7, p. 644, pl. 49, figs. 9-11; p. 645, fig. 2e.
1893 (1895). Opisthoptcra extenuata Ulrich, Geol. Sur. Ohio, Rep.,
vol. 7, p. 645, figs. 2a-d.
1893 (1895). Opisthoptera obliqua Ulrich, Geol. Sur. Ohio, Rep., vol.
7, p. 646, pl. 49, figs. 6-8.
1908. Opisthoptera obliqua Ulrich, Cumings, Dept. Geol. and Nat.
Resources Indiana, 32d Ann. Rep., p. 1012, pl. 47, figs. 2-2b.
[Same figures as Ulrich, 1893 (1895) above.]
Diagnosis.—Small Opisthoptera with little costellate
multiplication and an angle gamma of less than 65 degrees.
Description.—Shell obliquely elongate, with a posterior
wing; prosopon poorly known, there are about 20 primary
costellae, which as far as known increase only by bifurca-
tion; angle gamma, 50-60 degrees; angle beta, approximately
50 degrees; byssal sinus shallow; byssal gape poorly known;
no midumbonal keel; size small. Internal features unknown.
Synonymic discussion.—The three “species” which are
herein united under Opisthoptera alternata were described
by Ulrich on the basis of five specimens. All three
‘
“species”
are small, have an angle gamma of less than 65 degrees, and
agree well in general shape; there seems to be no valid ob-
jective basis upon which to separate them.
Ulrich (1893 (1895), p. 644) regarded O. obliqua as
differing from O. alternata in being more convex and in
having a flatter anterior side. O. extenuata was supposed to
differ in having a flatter anterior side and a more promin-
ent posterior wing. The only specimen of this species pre-
serving the posterior wing is the holotype of O. extenwata;
if the wing is disregarded the general shell shape and size
of O. extenuata (Pl. 42, fig. 11) are very similar to O. alter-
nata (Pl. 42, fig. 14). O. obliqua (Pl. 42, fig. 7) is also
similar to O. alternata in shell shape and size.
Types and materials—The only specimens of this
species available to me were Ulrich’s type materials of O.
alternata (U.S.N.M. Nos. 46262, 142827), O. extenuata
(U.S.N.M. No. 46266) ; O. obliqua (U.S.N.M. Nos. 46270,
142826) .
The type suite of O. alternata consists of two syntypes.
The specimen herein figured on Plate 42, figures 14-17 is
chosen as the lectotype of the species and has the following
dimensions: length, 11 mm.; height, 10 mm.; thickness of
a single valve, 4 mm.; and diagonal dimension, 13 mm.
The specimen figured on Plate 42, figures 12-13 is regarded
as the paralectotype of the species; it is a large highly dis-
torted specimen and probably does not belong to O. alter-
nata.
Distribution.—As far as known the species is restricted
to the Waynesville and Whitewater formations of the
‘Tristate Area of Ohio, Indiana, and Kentucky.
Remarks and comparisons.—This species may be based
upon young specimens of O. casei. Stratigraphically O.
alternata is distributed in the same formations as O. casei,
while morphologically the costellae of O. casei do not begin
subdividing until the individual reaches a diagonal dimen-
sion of 10-15 mm. This leaves only the distinction of angle
gamma whch could be smaller in young shells before the
anteroventral part of the shell begins to grow forward.
Lastly, it should be noted that Ulrich’s figures of O.
obliqua and O. extenuata are highly stylized; the specimens
upon which they are based are not so well preserved as his
figures indicate.
Opisthoptera species A, new species
Plate 44, figures 5-9
The specimens assigned to this species were collected
from several outcrops of the Elkhorn formation (uppermost
Richmond) near Batesville, Indiana. The available ma-
terial is not well preserved and may belong to O. casei.
However, it differs from O. casei in having an angle
gamma of about 90 degrees, smaller posterior lateral teeth,
and in lacking any trace of a m'dumbonal keel.
Opisthoptera gouldi (Ulrich in Hussey), 1926
Plate 42, figures 18, 19
1926. Opistholoba gouldi Ulrich in Hussey, Univ. Michigan, Mus. of
Geol., Contrib., vol. 2, No. 8, p. 165, pl. 8, fig. 1.
This is the type species of Opistholoba Ulrich in
Hussey (U.M. Nos. 9854, 9855). It possesses a posterior
wing and poorly known costellae which probably subdivide;
it is herein placed in Opisthoptera. O. gouldi differs from
other species assigned to the genus in that the posterior
wing is bilobed along its posterior edge (PI. 42, figs. 18, 19) .
So far as known the species is found only in the Richmond
of Michigan.
Opisthoptera griffini (Hussey), 1926
Plate 42, figures 20, 21
1924. [2] Opisthoptera fissicosta (Meek) [partim], Foerste, Canada
Dept. Mines, Geol. Sur., Mem. 138, p. 167, pl. 26, fig. 2; [won]
fig. 1.
1926. Anomalodonta griffint Hussey, Univ. Michigan, Mus. of Geol.,
Contrib., vol. 2, No. 8, p. 166, pl. 6, fig. 15.
The holotype of this species (U.M. No. 9876) possesses
a posterior wing, a small posterior byssal-pedal retractor
scar, and the posterior adductor is placed anterior to the
196 PALAEONTOGRAPHICA AMERICANA (V, 30)
center of the valve; the costellae are poorly preserved but
appear to subdivide. In addition, it has three posterior
lateral teeth.
The major distinctions from O. casei consist of the
larger angle gamma and three posterior lateral teeth in
the left valve, and the lack of midumbonal keel.
The specimen figured by Foerste (1924, pl. 26, fig. 2)
is similar to O. griffini in its general shell shape and angle
gamma, and it probably belongs to that species. Foerste also
noted that this specimen differed in its outline from O.
casei. This gives the species a distribution in the Richmond
rocks of Michigan, and probably Ontario.
Genus PALAEOCARDIA Hall, 1865
Plate 45
1865. Palacocardia Hall, Advance Printing for the 18th Report on the
New York State Cabinet, p. 37.
1868. Palaecocardia Hall, New York State Cab. Nat. Hist., 20th Ann.
Rep., 1st ed., p. 341. [Reprinting of Hall, 1865 above; title page
dated 1867.]
1870. Palaeocardia Hall, New York State Cab. Nat. Hist., 20th Ann.
Rep., revised ed., p. 389. [Essentially a reprinting of Hall, 1865
above; title page dated 1868.]
1871. Palaeocardia Hall, Geol. Sur. State of Wisconsin, 1859-1863,
Palaeont., part third, p. 45. [Essentially a reprinting of Hall,
1865 above.]
1889. Palaeocardia Hall, Miller, North American Geol. and Palaeont.,
p- 498.
1902. [Non] Palaecocardia Ameghino, Academia Nacional de Ciencias
en Cordoba (Republica Argentina), Boletin, tomo 17, p. 117.
Type species.—Palacocardia cordiformis Hall, 1865 (p.
37), by monotypy.
Discussion —The correct publication date of the name
Palacocardia is subject to the same uncertainties as the
name Amphicoclia. Both names were first used in the Ad-
vance Printing for the 18th Report on the New York State
Cabinet. Refer to the synonymic discussion of Amphicoelia
for the details concerning the 1865 Advance Printing.
Hall proposed this genus for a single costellate species
from the Niagaran of Wisconsin; while he did not formally
define the genus, he did assign one species to it and defined
and later figured this species.
Because Hall’s 1865 Advance Printing is difficult to
obtain, his description of Palaeocardia is quoted herein
(1865, p. 37):
GENUS PALAEOCARDIA (N. G.).
PALAEOCARDIA CORDIFORMIS (N. S.)
Shell cordiform; valves obliquely subovate, ventricose; umbones
gibbous, with the beaks prominent, attenuate and incurved; hinge-
line very short, extending a little in advance of the beaks, and showing
the margins separated. The anterior end gradually rounding into the
basal margin.
In the partial cast the posterior slope shows a ridge on each side
rising just behind the beak, and in a line slightly divergent from the
cardinal margin, reaching about half way to the posterior extremity,
where it becomes obsolete.
The surface is marked by fine close radiating striae.
This species has the general form of some of the more gibbous
forms of Ambonychia, but the short hinge-line separates it from that
genus, while the extreme prominence of the umbones and incurvation
of the beaks give it the aspect of a true Cardium.
The specimen was given to me by Dr. Day of Wauwatosa, who
informed me that it was found in a quarry a little east of that village.
Formation and locality. In limestone of the Niagara group, near
Wauwatosa, Wisconsin; in beds which are probably a little below
those of Racine and Waukesha.
The one specimen placed in Palacocardia by Hall is
herein figured on Plate 45, figures 7-10 (A.M. No. 2070).
This specimen shows little morphological detail other than
traces of costellae; in addition, the anterodorsal portion has
been poorly prepared. Hall did not figure this specimen
until 1868 and at this time he reversed anterior and pos-
terior, so that his figure of the right valve is actually a
figure of the left valve.
Palacocardia is probably an ambonychiid, but it is
founded upon such poor material that the name will prob-
ably have to be limited to Hall’s original specimen. Apart
from the type species of the genus only one other species
appears to have been assigned to Palacocordia, and this only
doubtfully as Palacocardia ? woodmani McLearn, 1924. Mc-
Learn’s species is also based upon one specimen which pre-
serves costellae, however, the specimen shows little else, and
McLearn was uncertain as to whether it was a right or a left
valve.
The name Palacocardia was also used by Ameghino
(1902, p. 117) for a genus of rodents; this was noted by
902% ps dO):
Ameghino with the new name drchacocardia.
Cossmann and he replaced Palaeocardia
Genus PLETHOMYTILUS Hall, 1883
This generic name is herein regarded as a junior
synonym of Mytilarca Hall and Whitfield, 1869 and is dis-
cussed under that genus.
Genus PSILONYCHIA Ulrich, 1893 (1895)
Plate 46, figures 1-6
1893 (1895). Psilonychia Ulrich, Geol. Sur. Ohio, Rep., vol. 7, p. 648.
1910. [?] Myalina Hind, Roy. Soc. Elinburgh, Trans. vol. 47, part
Bap 6499.
1934. [2] Psilonychia Ulrich, Isberg, Studien Uber Lamellibranchiaten
des Leptaenakalkes in Dalarna, p. 142.
Type species.—Psilonychia perangulata Ulrich, 1893
(1895) (p. 648), by original designation.
Discussion.—This is a poorly known genus which was
erected for forms with concentric prosopon and a prom-
inent byssal gape. These features combined with the lack
of an anterior lobe and a posterior alation seem to make it a
NortH AMERICAN AMBONYCHIIDAE: POJETA 197
distinct morphological form. The genus is recognized here-
in, despite the poor state of preservation of the type ma-
terial of the type species.
Ulrich assigned only one species to the genus, Psilony-
chia perangulata Ulrich. This species is based upon three
specimens (U.S.N.M. Nos. 46284, 142830), a holotype and
two paratypes. The paratype figured on Plate 46, figure 6
preserves the anterior face and shows the prominent byssal
gape and concentric growth lines; the lateral portion of this
specimen is poorly preserved.
Ulvich’s (1893 (1895) ) figures depict the holotype
(PI. 46, figs. 1-5) as an almost perfectly preserved specimen;
in reality it 1s poorly preserved. ‘The specimen shows little
of the ligamental structures and concentric prosopon, and
nothing of the posterior musculature. Apparently the
specimen was incomplete, for Ulrich rebuilt the antero-
dorsal portion with a beeswax-like substance (PI. 46, figs.
1-4). Because of this, little can be determined about that
portion of the specimen. Furthermore, Ulrich inked in the
posterior musculature and growth lines as well as part of
the byssal gape.
The genus seems to be unique in having concentric
prosopon and a prominent byssal gape, nothing else of its
morphology can be determined from the type materials.
Ulrich’s specimens are from the Corryville member of the
McMillan formation at Cincinnati, Ohio (Maysville). The
author has not been able to find any additional specimens
of the genus.
Isberg (1934) assigned one species from the Leptaena
limestone of Dalarna, Sweden, to this genus. His descrip-
tion indicates that he understood the generic taxobases for
Psilonychia, although his figures do not show a prominent
byssal gape. His figures show an edentulous hinge line and
duplivincular grooves and ridges, and because he under-
stood the generic taxobases for Psilonychia, his species
probably belongs to the genus. But until better specimens
of the type species are found this cannot be determined with
certainty, because the dental structures of P. perangulata
are completely unknown.
SPECIES LISTING
Psilonychia perangulata Ulrich, 1893 (1895)
? Psilonychia ulrichi Isberg, 1934
Genus STREPTOMYTILUS Kindle and Breger, 1904
1904. Streptomytilus Kindle and Breger, Dept. Geol. and Nat. Re-
sources Indiana, 28th Ann. Rep., p. 452.
Type species.—Streptomytilus wabashensis Kindle and
Breger, 1904 (p. 452), by original designation.
The species assigned to this genus are herein placed in
Mytilarca Hall and Whitfield, 1869; they may or may not
be retained in that genus when they are better known. The
generic taxobases upon which Streptomytilus was founded
are considered to be invalid (see pp. 145, 150), and the
genus could not stand upon these. Because there are no
unique features among the species assigned to Streptomy-
tilus upon which it could be redefined, it is herein dis-
carded.
AMBONYCHIID PHYLOGENY
The family Ambonychiidae is herein regarded as a
monophyletic taxon primarily on the basis of a common
morphological pattern possessed by the various genera
placed in the family. In attempting to trace the Ambony-
chiidae backward in time to some ancestral form I have
followed the common sense definition of monophyly ad-
vanced by Simpson (1959, p. 413):
. Evolutionary or so-called phylogenetic classification does not
express phylogeny but is based on phylogenetic interpretation of the
observational data. It is always necessary in a formal classification
(so unlike an actual phylogeny) to compromise sooner or later between
horizontal and vertical separation of taxa. That each taxon sometime
included only one species in its ancestry should be true, but it is a
completely impractical requirement that each taxon be so delimited
and defined as to include and begin with that species. In practice it is
a sufficient principle for evolutionary taxonomy that each taxon arose
wholly from one of lower categorical level, as Class Mammalia from
Order Therapsida.
However, even using this rather broad concept of mono-
phyly (to which all phylogenists do not assent) it has not
proven possible to determine the pre-Middle Ordovician
subfamily, tribe, or genus from which ambonychiids are
descended.
Pre-Chazyan (Early Middle Ordovician) pelecypod
faunas around the world are meager and not well known.
Cox (1959, 1960) briefly discussed most of the known pre-
Chazyan pelecypods. Subsequently, Vogel (1962) described
the new genus Lamellodonta from the Middle Cambrian of
Spain which he regarded as a pelecypod, and Robison
(1964) placed the Early and Middle Cambrian genus
Stenothecoides Resser in the Pelecypoda.
The closest probable pre-Chazyan relatives of the
ambonychiids are the cyrtodontids. This later family is
known from the Early Ordovician (Cox, 1960, p. 74) ; its
members are inequilateral (although this feature is not so
highly developed as in ambonychiids) , equivalved, and they
have the duplivincular type of ligament. On the other hand
cyrtodontids are strongly dentate (and at least in some forms
the teeth are crenulated), possess almost equal-sized ad-
ductor muscle scars, and are not known to have a byssus. In
198 PALAEONTOGRAPHICA AMERICANA (V, 36)
spite of the apparent lack of a byssus, many authors con-
sider the Cyrtodontidae as ancestral to the byssate Arcacea.
The feature which most strongly suggests a relationship
between cyrtodontids and ambonychiids is the duplivincular
type of ligament. This ligamental type occurs in several
more or less similar pelecypod stocks including the Cyrto-
dontidae, Arcacea, Ambonychiidae, Myalinidae, Pterineidae,
and the older Pectinacea. The common possession of a
duplivincular ligament suggests that these groups may have
TABEE Il:
: ORDOVICIAN
LOWER UPPER
Known _ stratigraphic
SILURIAN
LOURRRDERIEILECE
HERRBCRE Me diGe
CREEL LES RL LS
HIRT TTT TT
celebana comuucen
LOWER | MIDDLE | UPPER
had a common ancestry apart from other Paleozoic pelecy-
pod stocks. However, whether or not the cyrtodontids are
the immediate ancestors of the ambonychiids is uncertain.
The first ambonychiids to appear in the fossil record
(Early Middle Ordovician)
showing a complete or nearly complete loss of the anterior
are already highly specialized,
end of the shell. Correlated with the reduction of the an-
terior end there are a series of secondary specializations
which typically occur in byssally attached pelecypods. As
distribution of North American ambonychiid genera.
DEVONIAN
LOWER UPPER
GENERA
Allonychia
Ambonychiopsis
Amphicoelia
Anomalodonta
Anoptera
Ambonychia
Byssopteria
Cleionychia
Congeriomorpha
Gosseletia
Lophonychia
Maryonychia
Mytilarca
><
Opisthoptera
Psilonychia
Palaeocardia
|
|
|
|
NortH AMERICAN AMBONYCHIIDAE: POJETA 199
the anterior end was reduced the posterior musculature
moved toward the center of the valves giving increased
efficiency as the anterior adductor was lost. By the Late
Ordovician several monomyarian genera arose (é.g., Ano-
malodonta and Opisthoptera) and in these the posterior
musculature is nearly central in position. The byssus and
foot moved from the primitive ventral or anteroventral
position to an anterodorsal one, a condition similar to that
seen in the pectinaceans. In living pelecypods the byssal
gland is housed in the foot, and in ambonychiids the byssal
gape and sinus are located in the anterodorsal part of the
shell.
Yonge (1953) interpreted this type of change in the
position of the byssal apparatus as being due to a rotation
of the mantle /shell complex around the body of a pelecy-
pod. Stasek (1963)
position to be caused by variations in the relative propor-
considered this apparent change in
tions of different areas of the body and mantle ‘shell taken
as a unit, and not by a rotation of one around the other.
Whichever point of view one chooses to accept, the location
of the byssal apparatus of ambonychiids near the hinge line
indicates that the byssal gland and foot were not located
as these structures are found in dimyarian forms.
As might be expected the pallial line of the Ambony-
chiidae remained simple. The siphons and their muscle in-
sertions on the shell are not well developed in pelecypods
which attach themselves to the substrate. Usually there must
be some degree of imbedding of the animal in the sub-
strate before a prominent pallial sinus is formed.
Such features as radial or concentric prosopon, the
presence or absence of a discernible byssal gape, and various
combinations of dentition seem to be recurrent character-
istics among ambonychiids. They were probably evolved
more than once in different members of the family, al-
though
clusters of seemingly related genera.
particular combinations of them characterize
The presence of a duplivincular ligament is a primitive
feature in the Ambonychiidae and has been observed in
various genera ranging in age from Middle Ordovician to
Late Devonian. This type of ligament is morphologically
and physiologically complex, however, it appears at the
beginning of the phylogenetic history of the family and
must be considered a primitive feature of the group; it was
maintained throughout the history of the Ambonychiidae
and was passed on to their probable descendents, the Mya-
linids.
Throughout their known fossil record ambonychiids
can be divided into two groups based upon the presence or
absence of an anterior lobe. Those forms which possess the
anterior lobe are herein regarded as forming a_phyletic
line separate from the other genera. Following Dollo’s Law,
once the anterior end of the body is completely lost it is
highly improbable that it could be regained. ‘Therefore,
genera possessing the anterior lobe could have arisen only
from forms which possessed such a structure; forms lacking
this lobe could have arisen from either previously nonlobate
genera or from forms which still possessed the lobe. ‘Thus,
the nonlobate genera do not constitute a phyletic line of
their own distinct from that of the lobate genera.
It is assumed that the loss of the entire anterior end of
the body would represent a major phylogenetic trauma for
a pelecypod lineage; once this change occurred it is un-
likely that it could be reversed. The statistical probability
of a pelecypod repeating in reverse order the exact sequence
of mutations which resulted in the loss of the anterior end
is essentially zero. * major evolutionary steps are com-
pounded of many smaller steps, each preserved by natural
selection. That such a sequence, occurring by chance once,
should by chance be exactly reversed would be a most ex-
(Dodson, 1960, p. 154). I regard the
loss of the anterior end of the body of a pelecypod as a
traordinary thing”
major evolutionary step.
This interpretation of the phyletic history of the Am-
bonychiidae places the following genera on one branch of
the phylogenetic tree of the family: Allonychia, Ambony-
chinia (in part), Ambonychiopsis, Congerimorpha, Gos-
seletia, Paramytilarca, and Stappersella. The nonlobate
genera constitute side branches from the main lobate stem,
and in part also gave rise to each other.
The detailed relationships of the various genera of
ambonychiids are difficult to ascertain because a number
of genera are not well known morphologically. In some
cases the relationships are admittedly speculative, while in
other instances the proposed relationships can be stated
with a degree of assurance.
In the Chazyan rocks of North America only the
genus Cleionychia has been identified with certainty. This
genus lacks an anterior lobe but was probably hetero-
myarian for the posterior musculature had not yet migrated
out of the posterodorsal part of the shell. In Blackriveran
rocks both Ambonychiopsis and Cleionychia have been
found; the former genus still has an anterior lobe and, thus,
it is morphologically more primitive than Cleionychia.
The genera Cleionychia, Anoptera, Anomalocoelia,
Elasmodophora, Mytilarca, Praeanomalodonta and Psilony-
chia are tentatively considered as being phylogenetically re-
lated. All of these forms possess concentric prosopon and
lack an anterior lobe; beyond these features the genera are
200 PALAEONTOGRAPHICA AMERICANA (V, 36)
difficult to compare as the details of morphology known in
one genus are unknown in the others. Some species of Am-
bonychinia are shown by Isbere (1934) as having concen-
tric prosopon and lacking an anterior lobe; these species
also may belong to the above grouping.
{mbonychiopsis is the oldest known genus which
possesses an anterior lobe, and either this genus or some
form like it was ancestral to the lobate line of ambony-
chiid evolution.
Allonychia,
arose;
In the later Ordovician the lobate genera
Paramytilarca, and spec ies of Ambonychinia
these can be regarded as having been derived from
costellate Silurian Amphi-
Ambonychiopsis. “The genus
PRE- POST-CANADIAN ORDOVICIAN
CHAZYAN CINCINNATIAN
BLACK- TRENT-
RIVERAN] ONIAN
Maryonychia
ae
————
Opisthoptera
Ambonychia
\
\
aia
Anomalodonta
ee
or
| “Ambenychinia® |
Text-Figure III: Proposed phylogenetic relationships of the
coclia may have been derived from one of the Ordovician
lobate genera through suppression of the anterior lobe, or it
may have arisen from ribbed, nonlobate Ordovician forms
which developed a prominent anteroventral salient such as
Ambonychia caster’. In the Devonian the lobate line is rep-
resented by Congeriomorpha, Gosseletia, and Stappersella,
genera having arisen from unknown Silurian lobate types.
In addition to being the oldest known lobate genus,
Ambonychiopsis may have given rise to the Late Tren-
tonian and Cincinnatian genus Ambonychia by loss of the
anterior lobe, development of the monomyarian condition,
and formation of a prominent byssal gape.
SILURIAN
MED-
INAN
POST-
DEVONIAN
DEVONIAN
NIAG=
GAN
ARAN
Byssopteria
Lophonychia
Amphicoelia
Congeriomorpha
Myalinidae
Mytilarca
| Waieocear | acea
Ambonychiidae and of ambonychiid genera.
NortrH AMERICAN AMBONYCHIDAE: POJETA 201
In the Late Ordovician of North America, Ambonychia
underwent a prominent expansion and appears to have
been ancestral to Anomalodonta, Maryonychia, and Opis-
thoptera. These four genera have in common ribbed proso-
pon, monomyarian musculature, and a prominent byssal
gape. Anomalodonta is so similar to Ambonychia that it is
almost certainly descended from the latter genus. Both
genera are well known and differ only in their dentition.
Several species of Ambonychia are known in which
costae occasionally bifurcate, not as a regular feature, but
with individual variability. Accentuation of this feature
could have resulted in the multiple ribbing of Maryonychia
and Opisthoptera. Additionally, two species of Ambonychia
have small posterior alations; further elaboration of this
tendency could have led to the development of the promin-
ent wing of Opisthoptera.
The Devonian genus Follmannia appears to have some
relationship with Gosseletia and Stappersella based upon
the similarity of the dentition of the three genera. ‘The
origin of multiple costae in Follmannia is uncertain.
Lastly, the Silurian genus Palaeocardia and the Devon-
ian genera Byssopteria and Lophonychia are not well
known morphologically, and no relationships to other
ambonychiid genera are postulated for these forms.
Temporally the Myalinidae appear in the fossil record
at about the time that the Ambonychiidae die out. Both
the Myalinidae and the Ambonychiidae are anisomyarian,
integropalliate, byssate, prosogyrate, inequilateral, have a
discontinuous pallial line, and possess the duplivincular
type of ligament. The primary distinction between the two
families is that ambonychiids are equivalved and myalinids
are inequivalved. Among the Myalinidae the inequality of
the valves appears to have developed gradually and is ex-
hibited to different degrees in different members of the
family. Morphologically the two families are similar, and
both morphologically and temporally there are intermedi-
ates between them. The available evidence strongly suggests
a relationship between the two groups; herein the Myalini-
dae are regarded as having descended from the Ambony-
chiidae.
One of the oldest known myalinid genera is Septimya-
lina Newell, the oldest species of which occur in the Missis-
sippian (Visean) . The genus is almost equivalved, the right
valve being slightly smaller and flatter around the ventral
periphery than the left valve, and the prosopon is more
rugose in the left valve. Septimyalina forms an excellent
morphological and temporal intermediate between the
Ambonychiidae and the Myalinidae; whether or not it
actually served in this role cannot be determined at present.
However, its existence shows that such an intermediate
form could and did exist in nature.
In summary, the ambonychiids are Early Paleozoic bys-
sate pelecypods distinct from the mytiliform Modiolopsidae
and the inequivalved Pterineidae. They may have had a
common origin with the Early Paleozoic Cyrtodontidae and
Pterineidae based on the common possession of the dupli-
vincular type of ligament. Whether or not the Early Or-
dovician ancestor of the Ambonychiidae should be sought
among the Cyrtodontidae is uncertain; this latter family
differs from the ambonychiids in certain basic features.
The relationships of the various genera of ambony-
chiids to each other are largely speculative because of the
lack of detailed knowledge of many of the genera. It is
herein proposed that the anteriorly lobed forms represent
one line of ambonychiid evolution. The Late Ordovician
monomyarian ribbed genera appear to constitute a compact
closely related group forming a second phyletic line. The
taxonomy and the proposed phylogenetic relationships of
the concentrically marked nonlobate genera is unsatisfact-
ory. As a working hypothesis these genera are herein consid-
ered to form a phyletic line of their own, distinct from both
the lobate stock and the nonlobate ribbed forms.
Both temporally and morphologically the Ambony-
chiidae fit in well as the probable ancestors of the Myalin-
idae, the latter family having evolved from the lobate
ambonychiid_ stock.
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1916. The fauna of the Chapman sandstone of Maine. United
States Geol. Sur., Professional Paper 89, 347 pp., 27 pls.
————,, and Kindle, E. M.
1905. Contributions to Devonian Paleontology 1903. United States
Geol. sur., Bull., No. 244, pp. 118-125.
Williams, M. Y.
1919. The Silurian geology and faunas of Ontario Peninsula, and
Manitoulin and adjacent islands. Canada Dept. Mines,
Geol. Sur., Mem. 111, 195 pp., 34 pls.
Wilson, A. E.
1956. Pelecypoda of the Ottawa formation of the Ottarwa-St.
Lawrence lowland. Canada Dept. Mines and Tech. Svrs.,
Geol. Sur. Canada, Bull. 28, 102 pp., 9 pls.
Winchell, A., and Marcy, O.
1866. Enumeration of fossils collected in the Niagara limestone
at Chicago, Illinois; with descriptions of several new
species. Boston Soc. Nat. Hist., Mem., vol. 1, pp. 31-113,
pls. 2-3.
Woodward, S. P.
1851- 1856. dA manual ofthe Mollusca; or, a rudimentary trea-
tise of Recent and fossil shells. Pp. 1-158, 1851; pp. 159-330,
1854; pp. 331-484, 1856; 24 pls., London, John Weale
1871. A manual of the Mollusca. Second ed., 542 pp., 23 pls.
London, Lockwood and Co.
Worthen, A. H., and Meek, F. B.
1875. Descriptions of invertebrates. Geol. Sur. Illinois, vol. 6, pp.
489-532, pls. 23-33.
Yonge, C. M.
1953. The monomyarian condition in the Lamellibranchia. Roy.
Soc. Edinburgh, Trans., vol. 62, part 2, pp. 443-478.
rh
NortTH AMERICAN AMBONYCHIIDAE: POJETA
Zittel, K. A.
APPENDIX
TAXONOMIC KEY TO THE KNOWN GENERA OF
NORTH AMERICAN AMBONYCHIIDAE
a. Anterior lobe present 2
b. Anterior lobe absent 05)
a. Possessing only concentric prosopon an3
besRossessingysradiallimprosopomniercctsrcnses erence cere teers 4
a. Prominent byssal gape present Congeriomorpha
hs Discerniblesbyssall¥gapemabsent messsscescts eceeeresee tee: Gosseletia
a. Radial prosopon of costellae Ambonychiopsis
baRadialiprosoponofte costae) ceetsencrrcccce ester ee Allonychia
a. Possessing only concentric prosopon
b. Possessing radial prosopon. ............
a. Prominent byssal gape present
b. Discernible byssal gape absent
a. Length and height subequal ....
b. Height greater than length .....
a. Radial prosopon of simple ribs ....
b. Radial prosopon of multiple ribs ..........
a. Prosopon of costellae .....
b. Prosopon of costae
a. Prominent anteroventral salient present
b. Anteroventral salient absent «0.0.0.0... Lophonychia
a. Cardinal] and posterior lateral teeth present ............dmbonychia
b. Dentition limited to a single weak cardinal tooth in the right
Wi VCs sowsceacccesesceisiccas focesccssttsanetacs calesten dhe oteteee arene esas dnomalodonta
a. Prominent posterior wing; radial prosopon of multiple
costellae Opisthoptera
b. Posterior wing absent; radial prosopon of multiple costae ........ 13
a. Primary costae bifurcate, between each pair of secondary
costae there occurs an intercalated costa ..Maryonychia
b. Costae increase by both bifurcation and intercalation, in-
crease is highly irregular with no apparent pattern ..Byssopteria
The genus Palaeocardia is not included in the above
key. It is poorly known, and it is recommended that the
name be limited to the type materials.
207
1881-1885. Handbuch der palacontologic, Abtheilung 1, band 2.
Pp. 1-148, 1881; pp. 149-328a, 1882; pp. 329-522, 1884; pp.
523-831, 1885, R. Oldenbourg, Munchen und Leipzig.
PLATES
All figures are natural size unless otherwise indicated.
210
Figure
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 19
124. Alllonychias qamest, \(NCEK)) eescepss.cceccscessessterssesneseestestece onusecsuencotprnestsenesneeecmnetnareranaccemnrauerncectsss
5,6.
10.
UU
. Allonychia jamesi (Meek)
1. Right valve of the holotype. Cincinnatian (Upper Ordovician), Cincinnati, Ohio.
W.M. No. 556. 2. Left valve of the holotype. 3. Anterior view of the holotype. 4.
Dorsal view of the holotype.
Allama chia. 4 arniest A(UNTCCKS) Wieccrccsessve-csse-scstesctessneceesasasttresutestsestierenopaentrn ca neree aac recat cnet trersc secre cace
5. Right lateral view of Ulrich’s 1893 (1895) hypotype showing remnants of the pos-
terior muscle scars. Horizon: Corryville member, McMillan formation (Upper Ordo-
vician). Locality: Cincinnati, Ohio. U.S.N.M. No. 46079. 6. Anterior view of the
specimen shown in figure 5.
Anterior view of a specimen preserving a remnant anterior lobe. Horizon: Corryville
member of the McMillan formation (Upper Ordovician). Locality: Cincinnati, Ohio.
M.U. No. 74T. In addition to the Miami University accession number, the specimen
bears the number 46079. This is the same number which is present on Ulrich’s
U.S.N.M. hypotype figured above. The Miami University specimen may have orig-
inally been at the U.S.N.M.
EeAlllony chiaieg amesti | (NUceks) merece tersecectetstenccccsttcerevtarsececeaencce sensecanretstaeet an Qeceemece cuatarseresccteaesart
8. Anterior view of a distorted specimen showing a remnant anterior lobe. Horizon
and locality uncertain. Collector: Mr. E. Lomar. U.C.M. No, 35901. 9. Right valve
of the specimen shown in figure 8.
Ailloymohiay yamest (NECK) | waresccressscsnerstessscrenervecsewstssecnacscnscceanensatseasdaccecvenstersets see hucaceeees anti atanee
Right lateral view showing a prominent anterior lobe. Horizon: Corryville member,
McMillan formation (Upper Ordovician). Locality: Cincinnati, Ohio. M.U. No. 75T.
Aillomychianflanadg arvensis MEOCLUS tele y ct roses tiacorstissccetrecersrceceereonesnecsaresscecasstacesececes test cere
Right lateral view of the paralectotype. Horizon: Cynthiana formation (Middl
or Upper Ordovician). Locality: two miles north of Flanagan, Kentucky. U.S.N.M.
No. 142806.
oe
157
157
Plate 19
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 20
Figure
1 2e
3-7.
8,9.
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 20
ALO THY CRUGMLAILAGATLETUSISMIOETIStC mere ertercertre ee eee ee eee
1. Anterodorsal view of the upper umbo of the lectotype showing the incurved beak
and anterior lobe. Horizon and locality the same as the paralectotype figured on
Plate 19, figure 11. U.S.N.M. No. 78722. 2. Left lateral view of the lectotype.
FALLOT GHLGIN IL ANLCG ATT E71 SPSMBIO CTS UC Maamenestectsoeereret acer ne sey es tcccaeaete treet enenecdecteneteccectseeneseeeeTe ee
3. Anterior view of a right valve showing the incurved beak, anterior lobe, and lack
of a discernible byssal gape. Horizon: lower Cynthiana formation (Middle or Upper
Ordovician). Locality: Rose’s Farm on McClure Road, 1.9 miles south of the inter-
section of McClure Road and Colby Road, near Winchester, Kentucky. U.C.M. No.
35906. 4. Dorsal view of the specimen shown in figure 3. 5. Medial view of the speci-
men shown in figure 3. 6. Lateral view of the specimen shown in figure 3. 7. En-
largement of the posterior portion of figure 6 showing possible growth varices and
costae, (1.5x).
AU OPINEDIGE UCTEICOCGREIGES. UNSSRENS ppcaoccccosne etek SEC Lae BEERS ECESEE AEE SECC EEE CECE PEELED oC EOSPECOS
8. Dorsal view of a left valve showing two umbonal ridges and the anterior byssal
retractor scar (arrow). Horizon and locality the same as in figure 3. U.C.M. No.
35902. 9. Anterior view of the specimen shown in figure 8.
RPAlongichtamiplamagan erstsmM OCTS tous: cecsyescsettcccresnscstersstncctereuscarectenee erences esas e rae eeenee rete eese
Anterior view of a bivalved specimen. Horizon and locality unknown. U.S.
142807.
158
158
912
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 2]
Figure Page
i,
5-7.
8,9.
10,11.
16-19.
. Allonychia subrotunda Ulrich
Allomyohtia flan ag ammensis MOeTStes jesemencssssor:orerernssrantsswercerestcecerercestet enorme er ae 158
Medial view of the upper umbonal region of the specimen seen in figure 8, Plate 20,
showing the single anterior byssal retractor scar.
| Allonychia) sflanagamensts: Hoerstes eicrceseecc eetera eee eee e 158
Medial view of the upper umbonal region of a specimen showing two umbonal ridges.
Horizon and locality the same as in figure 3, Plate 20. U.C.M. No. 35903.
~~ Allony chia flamag ariersi sn Oeste sccrccrsccsescereceseecstereeessestteesteaetteteeee eee eee ee 158
Medial view of the upper umbonal region of a specimen showing the anterior lobe
and the anterior byssal retractor scar. Horizon and locality the same as in figure 3,
Plate 20. U.C.M. No. 35908.
DEA omy Ghia LAM agarveriSis) IOCTS {© Mes cereestecereseeeseeecryrs sesernesescenence eter omete eee eee eee ee 158
Lateral view of a left valve. Horizon and locality the same as in figure 3, Plate 20.
U.C.M. No. 35907.
UNREAL. HTD NOD WCW Petececr eee ceo cteoaece noc Paso cheep eacober oie sco ocan aso ponbacer La seandeeccbboa occ doncnueracnced 159
5. Anterior view of the holotype. Horizon: Fairmount member, Fairview formation
(Upper Ordovician). Locality: Covington, Kentucky. U.S.N.M. No. 46080. 6. Left
lateral view of the holotype. 7. View of the hinge line of the holotype, (1.5%).
Aillonychiay ovatal MUM mAGH cece scsccscen cs cccessstaesiecssaes sted cad aoe RT RTO 159
8. Anterior view of a paratype. Horizon and locality the same as in figure 5. U.S.N.M.
No. 142808. 9. Lateral view of the specimen shown in figure. 8.
Allonychia subrotunda Ulrich
10. Right valve of a previously unfigured paratype. Horizon and locality the same
as in figure 12 below. U.S.N.M. No. 142809. 11. Anterior view of the specimen shown
in figure 10.
12. Left valve of the holotype. Horizon: Corryville member, McMillan formation
(Upper Ordovician). Locality: Cincinnati, Ohio. U.S.N.M. No. 46081. 13. Right valve
of the holotype. 14. Dorsal view of the holotype. 15. Anterior view of the holotype.
ANU OTAVCHIOpSismUellistztataw (kali) Meese sesccce ree eee eee 163
16. Left valve of the lectotype. Horizon: Trenton limestone (Middle Ordovician).
Locality: Middleville or Trenton Falls, New York. N.Y.S.M. No. 2232. 17. Dorsal
view of the lectotype, (1.5%). 18. Anterior view of the lectotype showing what may
be a remnant of the anterior lobe, (1.5). 19. Right valve of the lectotype showing
costellae and concentric undulations.
wAmibonychzopsisnibellistrrat am (lalll)) ie ccrtescncsceursececesscesecosse-eoteceee erteer rete etree 163
20. Dorsal view of Ulrich’s 1894+ hypotype. Horizon: Prosser limestone (Middle
Ordovician). Locality: near Wykoff, Minnesota. U.S.N.M. No. 46084. 21. Left
lateral view of the specimen shown in figure 20, 22. Anterior view of the specimen
seen in figure 20 above showing what Ulrich regarded as the impression of a
“clavicle i(1-5@)).
l
5
Plate
RAPHICA AMERICANA, VOL. V
J
PALAEONTOC
f
.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 22
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 22
Figure Page
1. Ambonychiopsis bellistriata (Hall) ...2....:cscssssecsecesvescssssvescsscsesserssnecetecenscnsessreeneseenssscensnscssoseae 163
Enlargement of figure 21, Plate 21, showing the costellae, (1.5x).
2-5. Ambonychiopsis amygdalina (Hall) ....c..-..:c:.cssesscsscseseesectesesveeeeceeencenesisnesvecssesrensserseceseeeacans 163
6,7.
8,9.
10-12.
13-15.
16-18.
2. Right valve of holotype. Museum label lists the specimen as from the Trenton
limestone (Middle Ordovician), Adams, New York. A.M. No. 745/1. 3. Left valve
of the holotype. 4. Dorsal view of the holotype. 5. Anterior view of the holotype
showing the presumed “clavicular impressions.”
Ambonychiopsis amygdalina (Hall) ...ccccccceeeecee BE aS See PERRET rere
6. Left lateral view of Ulrich’s 1894 hyptoype. Horizon: Prosser limestone (Middle
Ordovician). Locality: 13 miles south of Cannon Falls, Minnesota. U.S.N.M. No.
46085. 7. Anterior view of the specimen shown in figure 6.
Ambonychiopsis affimis (Ulrich) ..c..sssccsssssescccsescccsescccnessesceseestentestsersssenerserssrectecnecnscsssaveneesecs
g. Anterior view of the paralectotype. The museum label lists the specimen as
from the Galena dolomite (Middle Ordovician), Spring Valley, Minnesota. M.G.S.
No. 8342. 9. Right lateral view of the specimen shown in figure 8.
Ambonychiopsis affimis (Ulrich) ......--.-.cc.-sssecseccssesccscseeseeessenececncersressestersneenssecnsasencenencensnnensens
10. Left lateral view of the lectotype. The museum label lists the specimen as from
the “Black River (probably upper Platteville), Carroll County, Illinois” (Middle
Ordovician). U.S.N.M. No. 46083. 11. Enlargement of figure 10 above showing faint
costellae, (3). 12. Oblique anterior view of the specimen seen in figure 10 showing
the “clavicular impression” and the smal] anterior lobe, (2X).
Ambonychiopsis orbicularis (Emmons) «...---..-:-:::::sssccseseseeteceseeeereescseerenssescseeeenenseseseecnenceneeenes
13. Anterior view of a Hall 1847 hypotype (pl. 36, figs. 5b-d). The museum label
lists the specimen as from the Trenton limestone (Middle Ordovician), Watertown,
New York. A.M. No. 716/1. 14. Left lateral view of the specimen shown in figure
13. 15. Dorsal view of the specimen shown in figure 13.
Ambonychiopsis orbicularis (Emmons) ..-.c.sccsssescessseesesccseescseesesecsseseseenesecnesssseetencensateneenenens
16. Dorsal view of a Hall 1847 hypotype (pl. 36, fig. 5a). Horizon and locality the
same as in figure 13. N.Y.S.M. No. 2233. 17. Anterior view of the specimen shown
in figure 16, (1.5%). 18. Right lateral view of the specimen seen in figure 16 show-
ing remnants of the posterior muscle scars.
162
162
213
214
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 23
Figure Page
1,2.
3-6.
“I
10,11.
12.
13.
16.
Ambonychiopsis orbicularis (Emmons) -...csccccsscsessecssesesssseesssesessseeneseeeeseoeneersrerseneensescesesstees 164
1. This specimen is a previously unfigured Hall hypotype. Horizon and locality the
same as in figure 13, Plate 22. A.M. No. 716/1. 2. Anterior view of the specimen
shown in figure 1.
Ambonychiopsis plamistriata (Hall) ....c.-.cccsccccesssecessecesecseessecessessesseensneueseesecancnssenteneneneacanees 164
3. Anterior view of Ulrich’s 1894 hypotype. The right upper umbo and beak were
reconstructed in dental wax by Ulrich. The museum label lists the specimen as
from the Platteville limestone (Middle Ordovician), Mineral Point, Wisconsin.
U.S.N.M. No. 46086. 4. Dorsal view of the specimen shown in figure 3, (1.5X). 5.
Right valve of the specimen shown in figure 3, (1.5). 6. Left valve of the specimen
shown in figure. 3.
922/1.
. Ambonychiopsis plamistriata (Hall) .......:cc.cccsesscsesseseeseseetesnerecesetecseeeeneensecerecensesnenssnsneensessacss 164
Right lateral view of the lectotype. Horizon and locality the same as in figure 7.
A.M. No. 922/1.
. Ambonychiopsis planistriata (Hall) .....-..s:csescesecseccescseeseecescecesereseeseesenecsessssesseneseensensnenneneensnss 164
This specimen is a previously unfigured Ulrich 1894 hypotype, (1.5>.). The museum
label gives no horizon but lists the locaiity as Mineral Point, Wisconsin. M.G.S.
No. 8327.
“Ambonychia” undulatus (Whitfield)) ...............cssccssssssssssnescsesneseasseeercnetecesnsreneseonssestsasannsesse 165
10. Anterior view of the holotype. The museum label lists the specimen as from
Niagaran (Middle Silurian), Wauwatosa, Wisconsin. U.S.N.M. No. 136763. 11.
Right lateral view of the holotype.
Ambonychiopsis orbuculants) ((EmMONS)) testes: cecssssestescssoseccostsnasesceseecssecererccesneeterapaeseesertescmrente™ 164
Right lateral view of a specimen showing the posterior adductor scar. According to
the museum label this specimen is early Trentonian (Middle Ordovician) from the
valley of West Canada Creek, probably near Gravesville, Herkimer County, New
York. U.S.N.M. No. 92311.
Aim bony ChLOPstsmOnDLCularis) (ESM ONS) \Mertaravencvcescsesseeceacestncecrareensnoteaectsinacerscersseneeceeta tree eens 164
Right lateral view of a specimen showing fine costellae, (2). Horizon and locality
unknown. U.S.N.M. No. 142810.
SpA ony htop siseionbcctlartsel (ESTIOUS) eiers.e-nscuctycxecceseteaeseecsescenaiecses sateen esereantttenes neasereceaaeremetrns 164
Right valve showing the single anterior byssal retractor scar, (3%). Horizon and
locality uncertain, U.S.N.M. No, 92313.
Aimibonychiop sigmorurcul arise (mM O18) ease -aceccessresatastetsacesnssesssnnevto te sratuosees cstamectcrenseraes tenetera tee 164
Right valve showing the posterior adductor scar and the costellae. Horizon and
locality unknown. U.S.N.M. No. 142811.
Ambonychiopsis sp. 160
Left valve showing the costellae. Trentonian (Middle Ordovician) Black Creek,
north of Russia, Herkimer County, New York. U.S.N.M. No, 142812.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 23
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 24
Figure
ie
11.
12.
NortTH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 24
VAN ORY CHLOP SIMU ELLs tr1at ame (Ed alll) Miecsstetttcsetscstesctetececsesecteseescctesrecteeresteceeneerecexesaeeereateesteeeveseene
Left lateral view showing the anterior lobe, (3). Age and locality the same as in
figure 16, Plate 23. U.S.N.M. No. 25789.
MeA nib OT ChiGPStsmp ellistn za lai (SAialll)) wmmectsrecerste trerecasesco-srvocksvsenesccncteterettestecteoreree eaceeeee et aeetoc terete
Right lateral view showing costellae, (3). The specimen is from Trentonian
(Middle Ordovician), near Poland, Herkimer County, New York. U.S.N.M. No.
99610.
3) AlN PHCOGITEL UGEGISO- TRIE coc Gescceercecotconceacccnt Sena seeree Se SpOCCCCASCEDECEECOCEEDAGoCE CHG Ea ceneer onaaroconnebececcCoLAsee
This. left valve is one of Hall’s original syntypic series. It is herein regarded as a
paralectotype. The specimen is from Niagaran (Middle Silurian), Racine, Wiscon-
sin. A.M. No. 2072/1.
MCA TUP AICO Eli cael Cal gftam id all ltperesncecesesceccete ces cosse ees cexscox:erccenccasnu cts ccecnsey spursedecesssoectiassecsseeercetecnestsrenassy
This specimen is a second paralectotype. Age and locality the same as in figure
3. A.M. No. 2072/1.
PRALTEP TCG Elam er chy ti" ENcal ea ccsterernees oases non neces on cer een aa Se acento duces ee soaseeaees Seal aA aoeee sean eae
5. Right valve of a third paralectotype. The specimen is from Niagaran (Middle
Silurian), Bridgeport, Illinois. A.M. No. 2072/2. 6. Dorsal view shown in figure
5. 7. Anterior view of the specimen shown in figure 5.
eA Up HICH Elf adler y teed alll eeecmteeersereee teers cece crac tase cee fates coesce arte sete ree tenete ste saeco Comet ears
8. Anterior view of the lectotype. Age and locality the same as in figure 5. A.M. No.
2072/2. 9. Dorsal view of the lectotype showing an anterior byssal retractor scar
in each valve. 10. Left lateral view of the lectotype showing remnants of the pos-
terior musculature.
Maumpiicoeliammeglectam (Nc Ghesney,)) pecssec-ccctsssccscetnrecectecstecscveseevsersccsasccecneersesesteoneareearetestoe
This specimen is Kindle and Breger’s 1904 hypotype, Niagaran (Middle Silurian),
near Delphi, Indiana. U.S.N.M. No. 62322.
Anmpbhicoeitammeglectar |(NICCHESnEY))) mevcceccecsaceesereen- ook seeee steed etree cattros steer easetece eee eee
This specimen is Whitfield’s 1882 hypotype. Niagaran (Middle Silurian) at Wau-
watosa, Wisconsin. U.S.N.M. No. 135946.
167
167
216
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PEATE 2
CK
Figure Page
Wp
6-8.
9,10.
Amphicoeliasmeglectan(\Mc@hesmey,), <cessssccsescctesscosercses tee eceeter sorte ee RE 168
1. Right valve of the specimen shown in figure 12, Plate 24. 2. Enlargement of the
costellae shown in figure 1, (3.7X).
HIGE Am PRIGO CLT. scccesssnnctucccstwcsavoncsasacovaedeosiesscuce dee orecansuecustacaevet rea sucaee near easen tae eeoee aiaeee ee 167
This is one of Hall’s 1879 hypotypes of 4. /eidyi. It is doubtful that its generic and
specific assignments can be determined. Niagaran (Middle Silurian), Waldron,
Indiana. A.M. No. 1949.
ALMUPRICO GLIA SP pacescccessskas ois desea ocateten rte eke gb Eo ae oes ASE RRR EE 136, 165
This specimen has the prominent anteroventral salient of Amphicoelia and also pos-
sesses concentric undulations. Niagaran (Middle Silurian), Wauwatosa, Wisconsin.
U.S.N.M. No. 142813.
2 Amphicoelian ctwA..letdiyt Fall seecsressecssteecoh coriome tierce tects coerce care eee eee ee Te 167
A large left valve showing the costellae. Age and locality the same as in figure 4.
U.S.N.M. No. 53204.
Anomaloadonta gigantea Nill eraesrcsancsttcctettere eet ese eT 170
6. Posterior view if the lectotype, showing the two shell layers, (1.5). The dashed
India ink line separates the two shell layers; the apparent layer to the left of the
solid line is not a part of the shell, The museum label lists the specimen as from
the Cincinnatian (Upper Ordovician) at Versailles, Indiana. W.M. No. 8851. 7. En-
largement of figure 6, (3). 8. Medial view of the lectotype showing the anteroven-
tral ridge which Miller regarded as an anterior adductor scar (arrow).
Anomalodonta gigantea Miillerpecescostceeree teeta cre meee 170
9. Posterior view of a paralectotype showing the shell layers, (1.5). Age and
locality the same as in figure 6 above. W.M. No. 8851. 10. Enlargement of figure 9,
(4x).
Plate 25
PALAEONTOGRAPHICA AMERICANA, VOL. V
re
a Bone
toe ety
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
4,
3-6.
11-13.
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 26
Amomalodontawglg arrears tecsecnesttcccrte rst ereneeess ener ccere erent re ncneraseercee steerer
1. Lateral view of the specimen shown in figure 9, Plate 25. 2. Medial view of the
specmien shown in figure 1. The apparent socket crossing the ligamental area is the
result of preparation by Miller.
PAPLOMLALOAONEGING LG GTi Le Gam Il erummenrtrectee eneter= teens terestecexcevectcretecdsccteapees /=zetsi-oeattes scsvesenereeeeronares
3. Dorsal view of a second paralectotype. Age and locality the same as in figure
6, plate 25. W.M. No. 8851. 4. Anterior view of the specimen seen in figure 3 showing
the byssal gape. 5. Lateral view of the specimen shown in figure 3. 6. Medial view of
the specimen shown in figure 3.
Himogialod ortamep scat ln chews seca terre reste eee soasea cee ceav eaten ccecctesssectee erecta
7. Lateral view of the holotype. Horizon: Corryville member, McMillan formation
(Upper Ordovician) , Locality: Cincinnati, Ohio. U.S.N.M. No. 46089. 8. Anterior view
of the holotype.
AMOMUAL OA OMG mOLG arite. cm IWidll ete cceetcsrcereceseneesesctet cree ets ne tee nerenseseneetecnnoeenonestancareacessss aescasceaserers
9. Lateral view of an Ulrich 1893 (1895) hypotype showing the bifid anterior byssal
retractor scar. The specimen is from rocks of Richmondian age (Upper Upper
Ordovician) at Versailles, Indiana. U.S.N.M. No. 46088. 10. Dorsal view of the
specimen seen in figure 9 showing the bifid anterior byssal retractor scar.
PA LOMUGLOMOMLAIIG LG QILLC aa NANI exam bnceccsresesseetes ts sece ee sencenesceanecnsennes scene seeeeesiererene a erereecesees 5
11. Dorsal view of a specimen showing a trifid anterior sal retractor scar. Hori-
zon and locality unknown. M.U. No. 71T. 12. Left valve of ie specimen seen in figure
11 above showing the pallial line and posterior muscle scars. 13. Anterior view of the
specimen seen in figure 11 above showing pronounced lateral displacement of the
pallial line in the region of the byssal gape.
VAimovialon dort amarg arte ceil leramencrecsscantccectassenteces sweet toreeseries cote se ocecse neem teeeree rere researc
Oblique posterior view of a specimen showing the two ostracal layers, (3). Hori-
zon: Oregonia member, Arnheim formation (Upper Ordovician). Locality: excava-
tion at the intersection of Westwood-Northern Blvd. and Boudinot Ave., Cincinnati,
Ohio. Collector: Mr. J. K. Pope. U.C.M. No. 35918.
170
a N7A0)
218
Figure
i;
2-4,
5,6.
7-9.
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 27
Page
Anomalodonta gigantea. Nialler cecccccce-cecsccrnsarsresersessevsesceresnetee cen sccesena neraeey tema nteeeene steer cee 170
View of the hinge line shown in figure 14, Plate 26, (1.5x).
Anomalodonta gigantea Miller gecen.ccccccccsrescorsrecseesacscctantecssne: totes casse.cerenassinacertenest tenes tere tec: 170
2. Left valve showing the posterior muscle scars. Horizon and locality unknown. M.U.
No. 831. 3. Anterior view of the specimen shown in figure 2, (1.5). 4. Dorsal
view of the specimen shown in figure 2, (1.5).
Amomalodonta gigantea Nien eyrcccc.cctcscercecerscecescnseceetsnesssesenecessesseere 5 1740)
5. Lateral view of a composite mold showing the posterior muscle scars. Horizon:
lower Fort Ancient member, Waynesvillle formation (Upper Ordovician). Locality
the same as in figure 14, Plate 26. U.C.M. No. 35896. 6. Anterior view of the speci-
men shown in figure 5.
AmomalodontangtganteamNiulllers eeeerccrtosre-cocacseneoscecerescemecereceresesseecetarncree mere attest eter nears 170
7. Dorsal view of a specimen showing the bifid anterior byssal retractor scar,
(1.5%). Horizon: “Hudson River Group” (Upper Ordovician). Locality: Versailles,
Indiana. Y.P.M. No. 23323. 8. Anterior view of the specimen shown in figure 7.
9. Left valve of the specimen shown in figure 7.
Plate 27
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 28
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-3"
4-8.
10-12.
13;5
14-17.
NortH AMERICAN AMBONYCHHDAE: POJETA
EXPLANATION OF PLATE 28
Anomalodonta gigantea Miller
1. Hinge line view of an incomplete specimen. Horizon: “Hudson River Group”
(Upper Ordovician). Locality: Versailles, Indiana. Y.P.M. No. 23324. 2. Lateral view
of the specimen shown in figure 1. 3. Ventral view of the specimen seen in figure
1 showing a natural anterior-posterior section through the shell, (1.5). The anterior
end is toward the top of the plate, and the shell material is to the left of the India
ink line.
Anomalodonta gigantea Miller ...........:.--::c-csceeseseeseseeeesreeseeesseneesssenssscnnnseaeaseensnsenensenensessscssss® 170
4. Left lateral view of an exceptionally well-preserved specimen. Horizon: “Hudson
River Group” (Upper Ordovician). Locality: Versailles, Indiana. Y.P.M. No. 23325.
5. Anterior view of the specimen seen in figure + showing the byssal gape. 6. Dorsal
view of the specimen shown in figure 4. 7. Posterior view of the specimen seen in
figure + showing marginal grooves and ridges, (1.5). 8. Medial view of the speci-
men seen in figure + showing the ligamental area and marginal grooves and
ridges along the anteromedial face, (1.5%).
. cf. Anomalodonta gigantea Miller ........--.-.-ccseccsesseseseescceeresesieneesesesseesesesssssnesneneenenensanensenensey 170
This specimen was placed doubtfully in this species by Hussey, 1926. Until the hinge
line is known the proper placement will be uncertain. Stonington beds (Upper Ordo-
vician), Michigan. U.M. No. 9825.
Amoptera misemert Ulrich .....cssecsesssecsecseessesseesseesnseseeriesneensesasesnecaseseccrseasensscnseanecnecnnecuncanecuuseneesyss 171
10. Left lateral view of the lectotype. Horizon: Whitewater formation (Upper
Ordovician). Locality: Richmond, Indiana. U.S.N.M. No. 46090. 11. Enlargement of
figure 10 above, (1.5%). 12, Dorsal view of the lectotype, (1.5).
Anoptera miseneri Ulrich...
Rubber cast of a paralectotype showing the prominent closely spaced growth lines.
Horizon: Waynesville formation (Upper Ordovician). Locality: Clarksville, Ohio.
U.S.N.M. No. 46091.
Amoptera misemert Ulich .....ccscescessesssessssseesseseesseseesesnessecnscvecnscssssccnessscnscseenecscenssseancansenseneescnneate 171
14. Left valve of a paralectotype. Horizon and locality the same as in figure 10.
U.S.N.M. No. 142814. 15. Dorsal view of the specimen shown in figure 14, (1.5X).
16. Anterior view of the specimen shown in figure 14, (1.5). 17. Right valve of
the specimen shown in figure 14, (1.5X).
219
220
PALAKONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 29
Figure Page
10.
14-17.
18,19.
Anomalodonta gigantea INUieTy secsscscecccesscsesecconssecseece trate rtccsscoasteeueneeeceaseneeteneancee eeetepetmenecees 170
Right valve of a composite mold. Horizon: Fort Ancient member, Waynesville
formation (Upper Ordovician). Locality: crossing of Middleboro Road and a small
tributary of Todd Fork, between Hicks and Middleboro, Ohio. U.C.M. No. 35878.
Aimopter amis eme rd WUOMGIC I ccccorcs cxsst ese cccs Se sorte eee esa care a oce ee eee eee cecen sane ence Tene eee 171
2. Left valve. Horizon: Whitewater formation (Upper Ordovician). Locality: two
miles south of Richmond, Indiana, on new Indiana route 27. U.C.M. No. 35925.
3. Right valve of the specimen shown in figure 2. 4. Anterior view of the specimen
shown in figure 2, (1.5). 5. Dorsal view of the specimen seen in figure 2 showing
a bifid anterior byssal retractor scar in the left valve, (5X).
ALTLOPLEHG) ATES CTLETU UNMTAGH asset recesses: cccseeenteeeew-neeteac sese ce teen nee cans Ware neK a see mre ee oe Son emer dona eNTanc nee er eee 171
Dorsal view showing a bifid anterior byssal retractor scar in the left valve, (6.
Horizon and locality unknown. M.U. No. 70T.
Amopleramangargt ale (EOC EStE)) 2 sccsscecstsssesseteeestoecesecesecacs toveceecer coveueeoromeene ero nee tee erate nL Tees 171
Lateral view of the holotype, (1.5). Museum label lists the specimen from Rich-
mondian (Upper Upper Ordovician), Stonington, Michigan. U.S.N.M. No. 78463.
Aino pteraamgusta IHOELStE)) | ccccaccecssessetesccserevaeeseneosscccvcodstesaes suneseve marenesstnneeon enone eoerece ence cemesseeerees 172
This specimen is one of Hussey’s 1926 hypotypes. Horizon: Stonington beds (Upper
Ordovician). Locality: east side of Little Bay de Noc, Michigan. U.M. No. 9818.
Anopterar angusta | (ROCTStE)) sce secnicessecsscecccucsnonscertnsuccancertictocooecetencereneseceses oerercaeere eeatcaeereeet nett tes 172
This specimen is one of Hussey’s 1926 hypotypes. Horizon and eee the same as
in figure 8. U.M. No. 9819.
Amb omy chia alata, NMeCeke sesccsceccceosstescase cases sdotes oo sn cacnaconssntacte conus eecentanasnenstcee onscadseee corse tercenenear antes 172
Lateral view of the plastolectotype. The original specimen Cincinnatian (Upper
Ordovician), Clinton County, Ohio. U.S.N.M. No. 67520.
Ambonychiavalata iWeekwpewucessssscccsrattices eens
Lateral view of a previously unfigured plastoparalectotype.
same as in figure 10. U.S.N.M. No. 142815.
Aimbonychia alata: Ne elke xc cseesecocecsrtene eee ot eae ener orca eT Estee eves hasten eee 172
12. Right lateral view of Ulrich’s 1893 (1895) hypotype. orizon: Arnheim formation
(Upper Ordovician). Locality: near Morrow, Ohio. U.S.N.M. No. 46087. 13. Rubber
mold of the specimen seen in figure 12 showing the posterior wing and posterior
lateral teeth.
Ambomy chiavialata Neel sci iietescs..sostveynsstassucesvortesne sane. iessiecees is tevsereess teen coon eend en eestor ete 172
14. Left valve of the holotype of Ambonychia costata Meek. Cincinnatian (Upper
Ordovician), Cincinnati, Ohio. W.M. No. 790. 15. Right valve of the specimen shown
in figure 14. 16. Dorsal view of the specimen shown in figure 14. 17. Anterior
view of the specimen shown in figure 14.
Ambonychia alata Meek .
18. Right valve of Foerste’s 1916 hypotype. Horizon: Waynesville formatiin (Upper
Ordovician). Locality: west of Madison, Indiana. U.S.N.M. No. 84928. 19. Dorsal
view of the specimen shown in figure 18.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 29
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 30
Figure
253"
67.
11-13.
14.
16.
19-21.
NortTH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 30
PA TOOERAIG, (AIOVTA NICE S cprrepereecerrn iosec0 09:0 ce ceLCO oO TETEC SPD CELE UB SSCEPID oO TEP CRUD EE ASERER OO ACESO eee 172
Hinge line view of a left valve showing the ligamental area and cardinal teeth,
(1.5). Horizon: Oregonia member, Arnheim formation (Upper Ordovician). Local-
ity: excavation at the intersection of Westwood-Northern Blyd. and Boudinot Ave.,
Cincinnati, Ohio. Collector: J. K. Pope. U.C.M. No. 35913.
ATEN OSNOLLG® NCTC ©. ocr rcpereeterenteee pacer SCC RRCERO Tee SECECCLASCUT PE BE EPCRE EER REE EEE Se eECe= eS ROSE 172
2. Dorsal view of a specimen showing the bifid anterior byssal retractor scar, (1.5X).
Horizon: Arnheim formation (Upper Ordovician). Locality unknown. M.U. No. 72T.
Anterior view of the specimen seen in figure 2 showing the byssal gape.
A mbonychia alata Meek
Dorsal view of a specimen showing the byssal retractor scar, (1.5x).
Horizon and locality the same as in figure 2. M.U. No. 73T.
Almmb ony chivas alata “NLCEK: tacceceacccsccecstessy vosesssosassevcassccsssutdecenste ecto let Sonnsetrev stasetciazeurscsevasddissnastetstsne 172
Left valve showing three cardinal teeth, (1.5). Horizon and locality the same as in
figure 1. U.C.M. No. 35914.
PLATED OTL CNT ALATA INUCEKE ieaencesssececessrssessrsucrensstcesnssnetesseovins setees>nonestecvestverar wsncsantatscvssnetybivtursetssestteve 172
6. Right valve showing the posterior muscle scars. Horizon: upper Arnheim forma-
tion or lower Waynesvillle formation (Upper Ordovician). Locality the same as in
figure 1. U.C.M. No. 35917. 7. Dorsal view of the specimen shown in figure 6,
(ESO)
PATIO O TEV GHC ALAL GIN Ce Kerrang etree acetone cay sansescts cue ssee son tu ec anven ohacerecesrecs seasU rae aeetey ous een ese seer gence eeere 172
Upper portion of a right valve showing the cardinal dentition, (1.5). Horizon
and locality the same as in figure 1. U.C.M. No. 35916.
PATTY OMY GR al ALA INC EKS ccereecncncctevacscstecysecscsaroersuisenesvnstevaronnessusaos aunccensst=e-cur sevchcseeseceenccrensbssctisvere 172
9. Hinge line view showing the cardinal teeth of the right valve, (1.5). Horizon:
Oregonia member, Arnheim formation (Upper Ordovician). Locality: excavation
for bridge at crossing of Ohio route 132 and Lick Run, near Roachester, Ohio. U.C.M.
No. 35917. 10. Lateral view of the spec:men shown in figure 9.
J NTO ICE ALTE ANG (CLS) et acre eg EE pice ace ee RR RCO er eRe ee re ore cr ner eer 172
11. Anterior view of a right valve. Horizon and locality the same as in figure 1
above. U.C.M. No. 35922. 12. Lateral view of the specimen shown in figure 11. 13.
Dorsal view of the specimen shown in figure 11.
Ambonychia alata Meek ... 172
Rubber mold of a specimen preserving the externa
the same as in figure 1. U.C.M. No. 35897.
Amb omy Chita ely oipt a (WELUSSE A) w-caee-tsczcccecsestecccsseceeaea tess ate ce-eeoeetoeteca eect tee cett eer erans reat civestecneerets 138
Lateral view of the holotype showing the posterior wing. Stonington beds (Upper
Ordovician), Michigan. U.M. No. 9834.
Atm bony Ghia alata NMC] KI er csccsaaasccssetasccssssxcveatectenc sceteey aise niente Ne ORONO EERIE Soe eae Eada dodo tno nOsea SharD 172
Rubber mold showing the posterior muscle scars and posterior lateral teeth.
Horizon and locality unknown. U.C.M. No. 35912.
LUTEAL LATTA AA TE® VAC) iene necret perce PPR Roe OEE EATER CCRC ES SECO eRe NODC EOE EEE EOE 172
Left valve of a partially shelled specimen (see Plate +7, figure 1). Horizon: Waynes-
ville formation (Upper Ordovician). Locality unknown. U.C.M. No. 19275.
PADI OVA CHL A ALaT ew NIC € kms te neers ras enone Sees Soe TR ie teat saat caeeBeaseks 172
Hinge line view of a right valve showing the cardinal teeth and collapsed liga-
mental area, (7). Horizon and locality the same as in figure 1. U.C.M. No. 35915.
TAG RTOECUTLD CACAALE. INANE) 6 certs e SSB Oca CoEECE OSAP OSE OEE ERE TECH OSOPEPRC EEC OSEE CED CE OCDCREEE ORCL ROPE 172
19. Anterior view of a left valve showing the byssal gape. Horizon and _ locality
the same as in figure 1. U.C.M. No. 35909. 20. Lateral view of the specimen shown
in figure 19. 21. Hinge line view of the specimen seen in figure 19 showing the liga-
mental area and cardinal teeth, (5x).
99)
999 PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 31
Figure Page
1,2. Ambonychia alata Meek .........:.:scccssesecesseeseeeeierecesssessseneessseesecevenencsesuevensansnanencccercnsrscecsensnatsnszes 172
1. Left lateral view preserving the posterior muscle scars, pallial line, and posterior
lateral teeth. Horizon and locality unknown. U.C.M. No. 35923. 2. Rubber mold of
the specimen shown in figure 1.
3-6. Ambomychia alata Meek .recccesccecssevssssccesseecessesesessseeesececneneneneensnesssssceseseneseneesenessonsusnenaneenenenees 172
3. Left lateral view of a shelled specimen. Horizon and locality the same as in figure
1, Plate 30. U.C.M. No. 35911. 4. Hinge line view of the specimen seen in figure 3
showing the ligamental area, cardinal teeth, and the more posterior of the two
posterior lateral teeth (arrow); the other posterior lateral tooth was destroyed
during preparation, (1.5%). 5. Dorsal view shown in figure 3. 6. Anterior view
shown in figure 3.
7-11. Ambonychia ulrichi (Pojeta) .....cccccscccecsesceeesereseeseseeeseseesessssecsseesassennsnesssceccssnesanenneneanenenness 174
7. Right lateral view of Hall’s 1859 (pp. 110 and 523) hypotype of 4. radiata. The
museum label lists the specimen as from the “Hudson River Group” (Upper Ordo-
vician), Lindleys’ Hill, Tennessee. A.M. No. 1124/4. 8. Anterior view seen in figure 7
showing the byssal gape. 9. Medial view seen in figure 7 showing the cardinal
teeth, (1.5%). 10. Dorsal view shown in figure 7. 11. Enlargement of the anterior
medial portion seen in figure 7 showing the cardinal teeth and marginal grooves
and ridges, (5X).
12-14. Ambonychia intermedia Meek and Worthen ............cssscccsssseseseceeecrecserecccseneneneeeeteeasscseesensnesens 138
12. Right lateral view of Ulrich’s 1894+ hypotype, (1.5%). The museum label lists
the specimens from Trentonian (Middle Ordovician), near Wykoff, Minnesota.
U.S.N.M. No. 46102. 13. Natural size figure of the specimen shown in figure 12.
14. Dorsal view of the specimen shown in figure 12, (1.5x).
AS =M7e Aan omy chia mo besa (WINICH))) ecececsescssectsreccsesessenscercstnee ezseuenerteeee acacteceereenesecunecatercecstsesuneesetrcoutuas 174
15. Dorsal view of a bivalved specimen showing a bifid anterior byssal retractor
scar in each valve, (1.5%). Horizon: Whitewater formation (Upper Ordovician).
Locality: roadcut 2 miles south of Richmond, Indiana, on new Indiana route 27.
U.C.M. No. 35921. 16. Right valve of the specimen seen in figure 15 showing the
posterior muscle scars, (1.5%). 17. Anterior view of the specimen seen in figure
15 showing the pallial line, (1.5%).
18. Ambonychia byrnesi (Ulrich)
Lateral view of a paralectotype. Horizon: Cynthiana formation (Middle or
Ordovician). Locality: Covington, Kentucky. U.S.N.M. No. 142805.
142
19 ern bony Chiam bayltve sda (Ulich) Wecestsres actesscrsctasscctcessscsstacosesneeerestenssareseneatteeteenesreeasneemnesemrereee 142
Lateral view of a paralectoype. Horizon and locality the same as in figure 18.
U.S.N.M. No. 142816.
PAV ZOE AGA: ((UUMWEKEN)) sccondcceenna-ntooparabexALcasd nach tnLatedo scene sede bbacoaovoncodecocoaccesc eegoctcefeoosreneccu 142
This specimen is herein chosen as the lectotype. Horizon and locality the same as in
figure 18. U.S.N.M. No. 46097.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 31
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 32
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 32
Figure Page
1. Ambonychia cultrata (Ulrich) el:
This specimen shows duplivincular grooves and ridges, a feature previously unre-
ported in the species. Horizon and locality unknown. M.U. No. 80T.
Dey CATO DIO ANE. CRA AGIETY (QOD). coccccisconssoccrosbannseeetaocecnsccendacoseosaccoetuetece coe yccbacecanpconsboncooaehoaneemee 174
This is a second specimen showing ligamental grooves and ridges. Horizon and
locality unknown. U.C.M. No. 35928.
Grp Aiyssoprentanradiatamed al lipemia cers cee tae ne ire op ree, eR ee 175
This specimen is the “matrix” covering of one of Hall’s syntypes of the species.
Museum label lists the specimens as from Chemung rocks (Upper Devonian), Mans-
field, Tioga County, Pennsylvania. A.M. No. 6115/1.
Tem S SOPLGGE aint @ ALG yt AME lalllerecccces sects ve teases csascr cca Scoie eet Se ev iss aso tee De BP ea Be 175
A left valve, Chemung (Upper Devonian), Mansfield, Tioga County, Pennsylvania
(see Plate 47, figure +). U.S.N.M. No. 100539.
5. Byssopteria radiata Hall
10-12.
. Cleionychia subundata Ulrich
. Cletonychia subundata Ulrich
Plastoparalectotype. The original specimen, Chemung (Upper Devonian), Mansfie
Tioga County, Pennsylvania. U.S.N.M. No. 68055.
PMB VSSODLERI Cana at atcammldell lig sertecrea cc crtces ecssrecice secs secase0F Cocca oases taste oe Oe he 175
A right valve, Chemung (Upper Devonian), Mansfield, Tioga County, Pennsylvania.
U.S.N.M. No. 100540.
MDS OPLER{ amr ant al cet lalll yemeceme te eke acc eee a Se es ON 175
This specimen is the lectotype (1.5) (see Plate 47, figures 2-3). Age and locality
the same as in figure 3. N.Y.S.M. No. 2294.
This specimen is a paratype (1.5x). : Cynthiana formation (Middle or
Upper Ordovician). Locality: mouth of the Licking River, Covington, Kentucky.
U.S.N.M. No. 142817.
Lateral view of the holotype, (1.5).
U.S.N.M. No. 46118.
Cleionychia excavata Ulrich
10. Dorsal view of the holotype. Horizon: Whitewater formation (Upper Ordo-
vician). Locality: Richmond, Indiana. U.S.N.M. No. 46113. 11. Left valve of the
holotype. 12. Anterior view of the holotype.
224 PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 33
Figure Page
1-35 Cletony chia larellowais (EWallll))) Secevccerssrcesceneestensessestsstasnstneszestests sents tessnutecneeentenerciceustta tartar neteeattss 179
1. Lateral view of the lectotype showing the posterior adductor muscle scar. Accord-
ing to the museum label the specimen is from the Trenton limestone (Middle Ordovi-
cian), Beloit, Wisconsin, A.M. No. 929/2,2. Anterior view of the lectotype. 3. Dorsal
view of the lectotype showing the anterior byssal retractor scar, (1.5).
AS GLeELOn Cia (Lar@eEllosaen (Mall) Wyetsseceeceescescedcarunnscaceaceneenetacsessoteesrennspeeeteeten tacraltnseeComesmeeterac enters 179
4. A paralectotype showing the posterior adductor muscle scar and what may be a
portion of the pallial line. Age and locality the same as in figure 1. A.M. No. 929/2.
5. Enlargement of figure 4 above, (1.5x).
65 Gletony chianlarellosa! (((Ealllll)\) cestcasy--cesccv-sxcortssxscoosesssosessseurnseccaecesteeeneens res sotee senna ceacereseenete centers 179
This specimen is a second paralectotype. Age and locality the same as in figure 1.
A.M. No. 929/2.
TeiGlevory chia aruellosa (klallll))l ces-cccecscsestrntheesce scones seasatsnaresctrecessterersssestecearesrmrecet nese easter 179
This specimen is a paralectotype. The museum label lists it from the Trenton lime-
stone (Middle Ordovician), Mineral Point, Wisconsin. A.M. No. 929/2.
SONG Letom chiaalarellowam (Klialll) i teses-cecsescsesceestursnesscncarastacssreanestessteveanacveresusnseetunsyeersestoeecneren antec 179
8. This is one of Ulrich’s 1894 hypotypes. Blackriveran (Middle Ordovician), Min-
neapolis, Minnesota. U.S.N.M. No. 46115. 9. Anterior view of the specimen seen in
figure 8 showing the lack of any discernible byssal gape, (1.5%). 10. Enlargement
of figure 8, (1.5X).
tin Vetory chia) armel Vols cig, (Elallll) Wtecescectesrertscceceserersrvavstsaceasteaees estes sedeateecennttces tenner cre sscereneserercnectare 179
This specimen is an Ulrich 1894 hypotype. Blackriveran (Middle Ordovician), Min-
eral Point, Wisconsin. U.S.N.M. No. 142818.
U2 GlerorEy Gide aTelLo's came ((kLallll)) lueeeeetentsretencemesreescecescventcsantsctaesanatacrmnaaecareeseswcnemi ts ccrescertonteeeeeteneer 179
12. Left lateral view of a previously unfigured Ulrich 1894 hypotype, (1.5). Age
and locality the same as in figure 11. U.S.N.M. No. 46114. 13. Anterior view of the
specimen shown in figure 12, (1.5%).
LA Sen GLesomychiamlaniella sain (kdalllll) feecesceeceterce cer cetetacsnetseeccesesetcesaretscarieacsac: eactareuienenteataectere seerceenete 179
14. Right valve of a previously unfigured Ulrich 1894 hypoytpe, (1.5). The speci-
men is from Blackriveran, (Middle Ordovician), Beloit, Wisconsin. U.S.N.M. No.
142819. 15. Dorsal view of the specimen shown in figure 14, (1.5).
N6:17. 1Gletony chiaglamellosas (Kall) cescecsrseccacesvsstencesretsnnorvestarssasucctressssnecternseeceatevsnceracetencesvencermaaes 179
16. Lateral view of an Ulrich 1894 hypotype, (1.5). Age and locality the same as
in figure 14. U.S.N.M. No. 46116. 17. Dorsal view of the specimen seen in figure
16 showing the bifid anterior byssal retractor sear, (1.5%).
18-20. Cleitonychia erecta (Hall)
18. Lateral view of the lectotype. According to the museum label the specimen is
from the Trenton limestone (Middle Ordovician), Beloit, Wisconsin. A,M. No. 931/1.
19. Anterior view of the lectotype. 20. Dorsal view of the lectotype.
Bega Gletony chia er ectain lial) esseseeceectorenccscesterrecessenesnreccuensaraqecs=cevseteneeg: eters cectenets -aetaetersnaner erate 178
21. Dorsal view of Ulrich’s 1894 hypotype, (1.5). According to the museum label
ic is from Blackriveran rocks (Middle Ordovician), Minneapolis, Minnesota. U.S.N.M.
No. 46112. 22. Lateral view of the specimen shown in figure 21.
23-24. (Gletonyohta mitida, Wilrich , .c.:.:scsscscesteceecs(eaneecheteee er eeec eee aaere tome eae nee eee Ree 179
23. Anterior view of the lectotype, (1.5). According to Bassler (1915, p. 241) the
specimen is from Blackriveran rocks (Middle Ordovician), Minneapolis, Minnesota;
the permanent museum label gives no indication of the age of the specimen, although
the field label lists the age as “Lower Trenton.”” M.G.S. No. 5099. 24. Lateral view
of the specimen shown in figure 23, (1.5x).
25..\Gleronychia erecta: \(Lall)! «.ccceccscveccssenscceccsvesepesds os ccutonerts Pereave cues openseetaete ot sobe ese nthe eT ETTORE 178
A paralectotype showing the anterior byssal retractor scar and umbonal ridges which
may represent atatchments of the general surface of the mantle, (1.5). Age and
locality the same as in figure 18. A.M. No. 931/1.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 33
Plate 34
PALAEONTOGRAPHICA AMERICANA, VOL. V
NortTH AMERICAN AMBONYCHIDAE: POJETA
EXPLANATION OF PLATE 34
Figure Page
1-3,
4,5.
6-8.
13,14.
15,16.
Gletonychiaaundatam IBMMONs) ete ee a ee 180
1. Right valve of Hall’s 1847 hypotype. Trenton limestone (Middle Ordovician),
Watertown, New York. N.Y.S.M. No. 2307. 2. Enlargement of figure 1, (1.5%).
3. Dorsal view of the specimen shown in figure 1, (1.5%).
Gletomychiamundatas (Emmons) erento ee eee 180
4. Dorsal view of Ulrich’s 1894 hypotype, (1.5). Prosser limestone (Middle
Ordovician), near Wykoff, Minnesota. U.S.N.M. No. 46119. 5. Lateral view of the
specimen shown in figure 4, (1.5).
Gletony chtamatienmatam (kal) irene eee ee Sa Re Ae Tn 180
6. Dorsal view of the lectotype. Ulrich (1892) placed this species in Cleionychia.
Museum label lists the specimen as from the Trenton limestone (Middle Ordo-
vician), Beloit, Wisconsin. A.M. No. 930/1. 7. Anterior view of the lectotype. 8. Left
lateral view of the lectotype.
. Cleionychia rhomboidea Ulrich 179
9. Dorsal view of the holotype. According to Bassler (1915, p. 241) the specimen
is from Blackriveran (Middle Ordovician), Minneapolis, Minnesota; the museum
label gives no data as to age or locality. M.G.S. No. 5526. 10. Lateral view of the
holotype. 11. Anterior view of the holotype.
MClctony Giiamqryitlotdes (ida) meetecemecenc ce eter eee ee Boot AERO SE a ee, 179
Lateral view of the holotype, (4). Chazy limestone (Middle Ordovician), Chazy,
New York. A.M. No. 536/1.
ERO CHAMP LGA ts lniclimeseeas ten sere seeteeres
13. Rubber mold of the holotype. 14. Holotype. Horizon: Fairmount member, Fair-
view formation (Upper Ordovician). Locality: Newport, Kentucky. U.S.N.M.
No. 46198.
Eridonychia paucicostata Ulrich
15. Holotype. Horizon: Fairmount member, ormation (Upper Ordovician).
Locality: Covington, Kentucky. U.S.N.M. No. 46200. 16. Rubber mold of the holotype.
995
996
Figure
8-10.
11-14.
15-18.
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 35
2. Anterior view of a Hall 1883 hypotype, (1.5%). According to Hall the specimen
is from the Hamilton group (Middle Devonian), Onondaga County, New York,
N.Y.S.M. No. 2438. 3. Right valve of the specimen shown in figure 2. 4. Dorsal
view of the specimen shown in figure 2, (1.5X).
BISQUE ENE: “Cis _ceceteccececeececocennaceeecetcocor oe SoeT cco Apne ceceTE oberg Lecechodssacosocto dace pvacebckoseucocacederosactecbes
5. Right valve showing the multiple costae, (2). Devonian, Kuahsinshan, Kitsing,
Yunnan, southwest China. U.S.N.M. No. 142820. 6. Anterior view of the specimen
shown in figure 5. 7. Left valve of the specimen shown in figure 5.
Gosseletia triquetra (Conrad) Ms
8. Left valve of the probable holotype, Horizon unknown. Locality: Oneonta, Otsego
County, New York. A.M. No. 5274/1. 9. Anterior view of the specimen shown in
figure 8. 10. Dorsal view of the specimen shown in figure 8.
Gosseletia niguwetral \((Comrad))|) %.-scss.c.cssscessnerecsneseceseosceseusasstuewsesene sett sovasnsettevercons-aesnstsoserererarirs
11. Right valve of a Hall 1883 hypotype. Age and locality the same as in figure 2.
N.Y.S.M. No. 2437. 12. Dorsal view of the specimen shown in figure 11. 13. Left
valve of the specimen seen in figure 11 showing two posterior lateral teeth. 14. An-
terior view of the specimen shown in figure 11.
Gosseletvantnigave tna (GOntmad|)fcecere-secececereeteteereceeteerecovenscceenoxsatecsmecesesteren sossunarcetearcamteeesenesesnsens
15. Rubber mold of the hinge line of a Hall 1883 hypotype showing the cardinal
teeth, (1.5). 16. Anterior view of the specimen from which the mold for figure
15 was made. According to Hall the specimen is from the Hamilton Group (Middle
Devonian), Fultonham, Schoharie County, New York. N.Y.S.M. No. 2439. 17. Lateral
view of the specimen shown in figure 16. 18. Dorsal half of the specimen seen in
figure 16 (with the upper umbo removed) showing the cardinal dentition and an-
terior adductor scar, (1.5).
Page
WE picdony chia scremata awl liichiseccecesve:t-cscvcronqesesccetceers torn rar tt iccetioan teres ree nescence soe teraz 182
Lateral view of the holotype. Horizon: Waynesville formation (Upper Ordovician).
Locality: Waynesville, Ohio. U.S.N.M. No. 46199.
miGosseletia trigwetray ((\Contad) ier r reecentte-cecteconeseteesesctecoxecconcnsteteenctretesssaetsncaastsaceesocseneP tasers 183
141
183
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 35
Plate 36
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1.
5-8.
9,10.
11,12.
13.
14,15.
NorTH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 36
Cosseletvaminigutern ams (Conrad) lemerceretert acts teticrtsss tte ieee ee
Left lateral view showing the complete anterior margin and the anterior adductor
scar. According to the museum label the specimen is from Hamilton drift (Middle
Devonian) at Ann Arbor, Michigan. U.S.N.M. No. 37523.
NG osseletvamintgicatraam (CG Ontadi Maceeccteet sess cotsecas ea cee tears eee Secon eea osteae
This specimen is an unfigured Hall 1883 hypotype. According to the museum label
the specimen is from the Hamilton group (Middle Devonian), Madison County, New
York. A.M. No. 5274/2.
pu Gowsaletiamenigietra (Contac) permease ctecriceccc esses tesa eee aceasta ne
Right lateral view of a Hall 1883 hypotype. Age and locality the same as in figure
2. A.M. No. 5274/2.
. Gosseletia triquetra (Conrad) 0.0.0.0... POCA EE AE ERP CoE er er en ee Re
Left lateral view of a Hall 1883 hypotype. According to Hall the specimen is from
Hamilton group (Middle Devonian), Fultonham, Schoharie County, New York.
N.Y.S.M. No. 2440.
Bopiomycuiaminig analem (Cleland))mesassssk tern athe reo ccee anette er
5. Lateral view of the lectotype showing the posterior adductor scar (1,5).
Horizon: Lake Church formation (Middle Devonian). Locality: Lake Church,
Ozaukee County, Wisconsin. U.S.N.M. No. 80288. 6. Dorsal view of the lectotype,
(1.5). 7. Anterior view of the lectotype showing what may be a small byssal gape,
(1.5). 8. Enlargement of the posterior adductor region of the lectotype showing
what appear to be costellae, (5x).
LOINEOTEWALYEE TERUG ORANE ((OUGENNGI) cccrecenen apsrebec Bebo cA cee NCD or EESE SRO COSEE REEL EE DLD OE ANCE P REECE ESOC
9. Dorsal view of the paralectotype, (1.5%). Horizon and locality the same as in
figure 5. U.S.N.M. No. 142821. 10. Left lateral view of the specimen shown in fig-
ure 9.
WVifargy On GRAGMGOTCOLC eT SE SIN (HOETSLE)) centre terete trie terecesreees scarce oe reese eee
11. Left lateral view of the holotype. Horizon: Arnheim formation (Upper Ordo-
vician). Locality: east of Concord, Kentucky. U.S.N.M. No. 84803. 12. Anterior view
of the holotype showing the byssal gape.
Vitaray OI Ch TGMGO 1LGOTd e12Si sun (MOCTSLE) misses eseeeceteancecee eco een meine eee
Rubber cast of an external mold of the species. The original specimen is from Clarks-
ville member, Waynesville formation (Upper Ordovician), Stony Run, downstream
from the crossing of Middleboro Road, between Ohio routes 350 and 22. U.C.M.
No. 35924.
Maryonychia concordensis (Foerste)
14. Anterior view of a shelled specimen showing the byssal gape. Horizon: Waynes-
ville formation (Upper Ordovician). Locality unknown. M.U. No. 79T. 15. Right
lateral view of the specimen shown in figure 14.
183
183
183
184
184
185
185
9I8
Figure
1-3.
10.
ital
13
14.
16.
17.
ihe
21,22.
. Mytilarca chemungensis (Conrad)
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 37
Mytilarca acutirostra (Hall) vessecscsscsecssssesseessscenscteceeneesscnsenessecsserecssereseensaneetsensesetaseneeneenennans 187
1. Left valve of the holotype. Niagaran (Middle Silurian), Milwaukee, Wisconsin.
A.M. No. 1951/2. 2. Dorsal view of the holotype. 3. Anterior view of the holotype
showing the byssal gape.
. “Mytilarca acutirostra’” (Hall) ssceccsecccsesccscccseessecceecteseerereesssesscsscassnesssessecrssececsrcneatsnsencenenesnsengs 187
This specimen is Hall’s 1882 hypotype. Niagaran (Middle Silurian), Waldron, In-
diana. It is doubtful that its generic and specific assignments can be determined.
N.Y.S.M. No. 2822.
. Mytilarca cf. M. acutirostra (Hall) ..ccccccccccsccssccesseesec sees renee tereerescesseenssenstsensneesensescsneseesssennes 187
5. Left valve of a specimen that appears to belong to this species. Niagaran (Middle
Silurian), Ridgeville, Randolph County, Indiana. U.S.N.M. No. 101612. 6. Anterior
view of the specimen shown in figure 5. 7. Dorsal view of the specimen shown in
figure 5.
. Mytilarca chemumgensis (Conrad) ...cccccercseseccesesvessesesseserseceeteceenesceseererersessnssennscescssessnsosssannsises 188
This specimen is a Hall 1883 hypotype. Chemung (Upper Devonian), Rockville,
Allegheny County, New York. A.M. No. 6110/1.
. Mytilarca chemungensis (Conrad) .ccccccecsccccsesecseseeseececeeseersnecseseesenecuserensenescesceenennensenerennerees 188
This is a previously unfigured Hall hypotype. Chemung (Upper Devonian), Philips-
burg, New York. A.M. No. 6110/2.
188
Mytilarca chemungensis (Conrad) : wes
This specimen is a Hall 1883 hypotype. According to the museum label it is from
the Chemung (Upper Devonian) at Rockville, Allegheny County, New York. A.M.
No. 6110/1. :
Mytilarca chemungensis (Conrad) ......cscscsscscssesscsecsssssssonssvenssensenenersccececerencenerccncetareessnesssesensrs 188
This is a Hall 1883 hypotype. Chemung (Upper Devonian), Randolph, New York.
N.Y.S.M. No. 2826.
This specimen is a Hall 1883 hypotype from the Chemung group (Upper Devonian),
Philipsburg, New York. A.M. No. 6110/2.
Mytilarca chemungensis (Conrad)
Left lateral view of a Hall 1883 hypotype from the Chemung group (Upper Devon-
ian), Rockville, New York. A.M. No. 6110/1.
Miytilarca, chemung ests) (Conrad) rccacessesccstcsseostscscstienceataenntanerstecvensae eerencenesctewecerwecenaneceenenerae 188
Right lateral view of Walcott’s 1884 hypotype. Upper Devonian, Eureka District,
Nevada. U.S.N.M. No. 13886.
wiv tilarcanchemungertstsim (Comma d))eswecsscecsssccttucusvascecsesesvencctcesccrmnecarneresr-eresternereseceentepteetasretas 188
This specimen is an unfigured Hall hypotype of M. carinata. Chemung group
(Upper Devonian), near Elmira, New York. A.M., bears no number.
Miytilanca chemangensts) \((Comuradi))) cocs-cscereecesecsesseee stesatsnnssessceatonateesceasrsrsrtecaremnmenteevanrennceresees 188
This specimen was placed in M. carinata by Hall. Chemung (Upper Devonian), near
Elmira and Factoryville, New York. A.M. No. 6109/2.
Miytilancarch emu giensisin(C@ormad)))eeccccceeeee te etecsteevesstentenneere cnerseenteardeteamesesecenerertsamenrecrespeeetceree 188
This specimen was placed in M. carinata by Hall, Chemung group (Upper Dev-
onian), near Elmira, New York. A.M. No. 6109/2.
mVigtilarca. chemung e7stsia (| COmnmad)))ees.-ctecsssececess.nereceseeucvanerecavassentsstesctendet-eeastnneteasetsneneecteeeneeaee 188
Left lateral view of Butts’ 1941 hypotype from Upper Devonian, Virginia. U.S.N.M.
No. 98020.
Muy tilancassig tila Wall Wercer csc cetecnece erst sceerecsetereanreomenrensnassetees oreo ateneaeer eee an eee ne neces 188
Lateral view of the holotype. Niagaran (Middle Silurian), Waldron, Indiana. A.M.
No. 1948.
DMigtilanca: foerste: | Clarkerand Ruedemann sz.ssrccstcscsctsates.csesasase sans eatessracsteeerenan cosa rennet 188
Lateral view of the holotype. Horizon: Brassfield limestone (Lower Silurian).
Locality: 2 miles north of Wilmington, Ohio. U.S.N.M. No. 88537.
Mytilarca sp. ee HES
21. Lateral views of three specimens showing ligamental grooves and ridges and
cardinal and posterior lateral teeth, (3). Horizon: Edmunds formation (Upper
Silurian). Locality: Whitings Bay, Washington County, Maine. U.S.N.M. No.
101593. 22. Individual view of the specimen shown in the lower left of figure 21,
(3X).
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 37
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 38
Figure
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 38
ieeVipiilar.camcherarig errsts a (( CONTA) | teceeveecears-ceseesssestessenence ceaetnceesereercsavedetcnenececcnecseernccereecrcsrsrscase
3, 4:
10.
11-13.
14-16.
18.
19,20.
21.
22-24.
This specimen was originally placed in M. carinata by Hall and was chosen as
the lectotype by McAlester (1962). Chemung (Upper Devonian), Chemung Creek,
New York, A.M. No. 6109/2.
. Mytilarca chemungensis (Comrad) .....c.cccccscscsescsseescsnecteneneesnseseensesescensnecseneenscensesesesennsssenesenens
This specimen is the holotype of M. attenuata. The specimen was collected from
glacial materials near Elmira, New York. N.Y.S.M. No. 2824.
Ne chemungensis KEG co rains a Gt) eee sae see ccc cesancesncens commecen ore se ieee nests ave cen ssenteaescasesrecisarsnen tesa
This specimen was originally placed in M. carinata by Hall. It shows posterior
nee teeth and remnants of cardinal teeth. Chemung (Upper Devonian), Chemung
Creek, New York. A.M, No. 6109/2.4. Enlargement of figure 3 (1.5x).
. Mytilarca che mungensis (Cia aye) cepa ees sacecerocenonacaret cto soseecec co 30" 0cEAc0 99s cOEEAS coe EOLECLECCERE RES SDC
Right lateral view of a specimen originally placed in M. carinata by Hall. Chemung
(Upper Devonian), near Elmira, New York. A.M. No. 6109/1
meMigtilarca, dalhowsed (Clarke. (i.-c..:.20c<cacossssqs-sonccsonveree cen ccccseneetenccnncctctrensecsrsrnaraeeernssecasresertestsraszz==
This is a Clarke 1909 hypotype. Horizon: Dalhousei shale (Lower Devonian).
Locality: Stewart’s Cove, Dalhousei, New Brunswick, Canada. U.S.N.M. No. 56783.
: OO ae ediitpormmisn Clarke sande RUCGEMIADM peers ccsusessccossnsnsesetelesepSrsyaccercr gemrecsseesscereeesosers
Right valve of the holotype. Horizon: sue dolomite (Middle Silurian). Lo-
Gallity: Rochester, New York. N.Y.S.M. No. 9131. Anterior view of the holotype.
. Mytilarca mitida Billings .........-.-....sssscssesecsesesssseesecssnceeeseerercenscesscsscecsncensvcnssssosenienanssnssacsarsanensass
Right lateral view of Clarke’s 1908 hypotype; its assignment to this genus and
species must be considered doubtful. Grande Gréve limestone (Lower Devonian),
Quebec, Canada. U.S.N.M. No. 56782.
Mytilarca chemunge SUSMm( GOMIGAGN luneteesceesentee tan eer crenestcceveceecesstecerenscorescecee asacoracereeemeecmmamactns™
This specimen is a Hall 1883 hypotype showing een grooves and ridges,
(6X). Upper Devonian, Rockville, New York. N.Y.S.M. No. 2825.
Viiiiilare metbru ornate lel Wrectearecserecccrcsenccecenateeaereee=teees-teeree:feet-rsraetnecsceecescnereatnrncsesrercseracranvenacns
11. Dorsal view. This specimen is herein chosen as the lectotype. Chemung rocks (Up-
per Devonian), Ithaca, New York. A.M. No. 6112/1. 12. Right valve of the lecto-
type. 13. Anterior view of the lectotype.
Wiytalar-camd al notese tn Clan KOw ceceancesescestacenesereee ntepmcteneo we merrier ennencchene teerecenaennsrnaeencenttessrr acc crernrese
14. Hinge line view of the holotype showing three posterior aoe teeth, (1.5X).
Horizon and locality the same as in figure 6. N.Y.S.M. No. 8931. Anterior view
of the holotype. 16. Left lateral view of the holotype.
BeViigiilancamadal ot se tal Clarke meatertecssteresceasaterarentenacteckatectertenetarteesansrte ences anerttten-e-menaseteerreeeratead
This specimen is a Clarke 1909 hypotype. Horizon and locality the same as in figure
6. N.Y.S.M. No. 8932.
Mipiilarzcaapyniriad atl lal Wemscescscsrsscesaesescetsnctesensencneantenewreracanscer aura aeeeteasrenearacatenecetteraeeenees eres
Left valve of the paralectotype. According to the museum label it is from the Scho-
harie grit (Lower Devonian), Schoharie County, New York. N.Y.S.M. No. 2835.
Wisyiltomec: @abpGpeblgGe VER erpscncceoceroconconepsasconenco oeconneo cae ccee aoncee eto -oarocnocrosed ogee abencaccocooceceococoseeto
19. Right lateral view of a syntype. Horizon: Milwaukee formation (Middle Dev-
onian). Locality: Milwaukee, Wisconsin. U.S.N.M. No. 80284. 20. Anterior view
of the specimen shown in figure 19.
Mytilarca regularis Meal Litre cece croscacseeeevost acess erences carers esate tact ene getesteen musecnsastsestoetenerecscass
Left lateral view of the holotype. Chemung (Upper Devonian), Leon Center, Cattar-
augus County, New York. AM. No. 6111/1.
Mytilarca pyrimadata EVD oer ee tess coset cesta recat ccecsnsceceveesectestasscsesres ons cnstus <Cizetocssvsisstecstultvecrbexvies
22. Dorsal view of the specimen herein chosen as the lectotype. Horizon and locality
the same as in figure 18. N.Y.S.M. No. 2834. 23. Right valve of the lectoytpe. 24. An-
terior view of the lectotype.
188
188
188
189
189
188
189
189
189
190
189
190
229
230
Figure
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 39
1. Miytilarca lata Wall cecsccsecccsecsssosssoseessssessessssesccsssseenesseneteeiscnsneceessevsescngscusstenonsensencnarnesnengantnegaseaes 189
nN
5,6.
10,11.
13.
14,15.
ie
. Mytilarca suberectus (Pohl)
Lateral view of the holotype. Chemung (Upper Devonian), Randolph, New York.
N.Y.S.M. No. 2828.
| May tilarccan gab boa aa eeccereeccecsetescss ens. +00co-nasnscoeor=senevsntonetetasrtcnversecrs ivan cetenret: cnaerrsrageeare seattaeearnerees 189
This specimen is the holotype. Chemung (Upper Devonian), Napoli, New York.
N.Y.S.M. No. 2827.
« Miytilarcca’ sim plez Hal .-c.-ncccveccscssescssoe.csvsssceonsronsrcestacoarecsrtnencscesesenssaerneaducruecaesresstscnasszascnscasscnansee 189
This specimen is herein chosen as the lectotype. Chemung (Upper Devonian), west
of Smethport, Pennsylvania. N.Y.S.M. No. 2837.
. Mytilarca simplex Hall ....2-.:cssccesscessesscscceccesseeseeeeeccsssrenesecscsassssvessntecsscscstscnsssescnssaseneneanenernancens 189
Paralectotype. Age and locality the same as in figure 3. N.Y.S.M. No. 2836.
Mytilarca suberectus (Pohl) ..scesecssssecsesecsesecsestesecseseneceesessessesssensseenssessrescesesseaeeceasenscnceatnses 190
5. Right valve of a syntype. Horizon: Milwaukee formation (Middle Devonian).
Locality; Milwaukee, Wisconsin. U.S.N.M. No. 80227. 6. Anterior view of the
specimen shown in figure 5.
Left valve of a syntype. Horizon and locality
No. 142822.
. Mytilarca suberectus (Pohl) ....ssccsecscsscsecsecseseesseceseenessecnscsecseessessessssuseestesseeseenseseessennensennense 190
This specimen is a syntype. Horizon and locality the same as in feGne 5. U.S.N.M.
No. 142823.
. Mytilarca suberectus (POonl) sees seseeseesscsnessesssensesseescssscessseseseceassnensnecasenneanecsiss 190
Right lateral view of a syntype. Horizon and locality the same as in figure 5.
U.S.N.M. No. 142824.
Mytilarca SALDETECLILS UR OLMI) recta cc sanconcecwncescacosie cereus ares Cannneses int WrantdsstevAadanastsuc(estn #ts-s east nosnacectes 190
10. Anterior view of a syntype. Horizon and locality the same as in figure 5. U.S.N.M.
No. 142825. 11. Left valve of the specimen shown in figure 10.
“Mytilarca” occidentalis (White and Whitfield) .........-secssccssessessesssesssescnsscseeensesseeesetenneeess 187
This mytiliform shell is not regarded as belonging to Mytilarca. Hall (1884b) listed
the specimen as coming from the “Yellow sandstone, at Burlington, Iowa’ (Upper
Devonian or Lower Mississippian). A.M. No. 6533/1.
“Mytilarca” fibristriata (White and iWihiithiel’d)) freccqcectanseeccessasesssctomteeteeeccresecmsteressascecacerees 187
This mytiliform shell is not regarded as belonging to Mytilarca Hall (1884b) listed
the specimen as coming from the “Yellow sandstone at Burlington, Iowa” (Upper
Devonian or Lower Mississippian). A.M. No. 6532/1.
“Miytilarca” fibristriata (White and| Whitfield) .....--.0.....:s.csescsercrsccesccesectreccssecnscersecsnserrterses 187
14. This mytiliform shell with radial prosopon is not regarded as belonging to
Mytilarca, (1.5%). Hall (1884b) listed the specimen as coming from the “Yellow
sandstone at Burlington, lowa” (Upper Devonian or Lower Mississippian), A.M. No
6532/1. 15. Natural size view of the specimen seen in figure 14.
| “Miytilancavagessiee! Millers amd Gurl eyptececcececs-ccecetencncacteesereenscsncet fetes cesaseneaas eeetnercerenea tees 187
This mytiliform shell is not regarded as belonging to Mytilarca. Syntype. Chouteau
limestone (Lower Mississippian), Sedalia, Missouri. U.C.M. No. 3925.
Miytilanca’sajessveaem Mille mean dk Git] eNgieeseccsecccss-cteretestser’cencecnarcsetiece eet eeterroes caeereeereatraretenet 187
Second syntype, (1.5). Horizon and locality the same as in figure 16. U.C.M. No.
3924.
. “Miptilarcaag essveae Niillexmand |: Giutil eyaereeverctereececnect erases ccterererrecvenshcceersasertat sisearuater Rereaeaanngres 187
Third syntype, (1.5). Horizon and locality the same as in eure 16. The seem-
ingly prominent growth lines were inked in by the original authors. U.C.M. No.
3927.
‘Miytilancar jessteae Miller wand G ut) eyawertccrrssnsccest cerecriceteneestaser7.cerststetearernear terete ceerenanes 187
Fourth syntype, (1.5%). Horizon and locality the same as in figure 16. The seem-
ingly prominent growth lines were inked in by the original authors. U.C.M. No.
3926.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 39
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 40
NortTH AMERICAN AMBONYCHIIDAE: POJETA 251
EXPLANATION OF PLATE 40
Figure Page
eV ttl Ar Car nab Tam WWialC Otten sceree cree reste eer ne ee a eee 189
Lateral view of the holotype. Lower Devonian, Lone Mountain, Nevada. U.S.N.M.
No. 13885.
Zea eViyitlancavanenacea Lalande VVibititel ds sccceccsrssss:ccescecsescestereaee seers cereresaceoscanccatesersueeseresceseceoescs 189
2. Anterior view of the lectotype. Schoharie grit (Lower Devonian), Schoharie,
New York. N.Y.S.M. No. 2823. 3. Lateral view of the lectotype.
AmVinilarcananenaceanblallmandmvvinittiel dcssssrcccsesccerereeeecttateton eee ee icceees
Lateral view of the paralectotype. Horizon and locality the same as in figure 2.
A.M.‘No. 2839.
EiGuVinitt ancamaumeniise (kindlemanda Bie gery) imeceeacterntseesen centre sseas i eecescereeeresre cr ceeseetoe erase 188
5. Dorsal view of the holotype. Niagaran (Middle Silurian), Georgetown, Indiana.
U.S.N.M. No. 62321. 6. Left lateral view of the holotype.
-SomVinyitlancampornderos am blallieama) AVWinitLve ly pcsccecce-cer-cceeseecsecceesseecteseeceeseroesteseesesseasevecueeceseesen 190
7. Dorsal view of a paralectotype. According to the museum label the specimen
is from the upper Helderberg limestone (Lower Devonian). Clarence Hollow,
New York. A.M. No. 3093/5. 8. Anterior view of the specimen shown in figure 7.
9. Left valve of the specimen shown in figure 7.
NOS emit ay Garp Rae cm (IEA allll)) recrececccexscesecscecsscectaetesentcctenctcrene Sues ctenese tame awecverenterarseseesatroncece encaneeateves 187
10. Left lateral view of the holotype. Niagaran (Middle Silurian) of Illinois. A.M.
No. 2068/1. 11. Anterior view of the holotype. 12. Dorsal view of the holotype.
13 a4aMipitlancamponrderosantlal leanduavyliittiel dh acesccsccsserstecssosavceceesconseccesceseceeceseserecreneeseseenstennorera 190
13. Left lateral view of a lectoparatype. Horizon and locality the same as in
figure 7. A.M. No. 3093/5. 14. Anterior view of the specimen shown in figure
13:
oem Viyitarcamponderocametallm@annd myvinitriel dime carcscseccevescsacecssotostonestscesteureteccererstressteresesce eee 190
Anterior view of the lectotype. According to the museum label the specimen is from
the upper Helderberg limestone (Lower Devonian), Columbus, Ohio. A.M. No.
3093/3.
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 41
Figure Page
22 Miytilanca, ponderosa Malllland) \Wihithieldl p.csscccscstecersseteceeereree cere eect corer rete ee 190
1. Right valve of the lectotype. See figure 15, Plate 40, for the horizon, locality, and
museum number of this specimen. 2. Dorsal view of the lectotype.
BeViytilarca lowiporanis: | ((Conmad))eseserscececccseceetee ees eeeee e 190
Right lateral view of a Hall hypotype. According to the museum label the specimen
is from the Hamilton group (Middle Devonian), Livingston County, New York.
A.M. No. 5275/3.
AN Mipttlarca towiforgis as ((COnTnad)) iy mececseccess tasers eae eee eee eT 190
Right lateral view of a Hall hypotype showing the posterior lateral teeth, (1.5%).
According to the museum label the specimen is from Hamilton beds (Middle
Devonian), York, New York. N.Y.S.M. No. 2833.
5,6. Mytilarca ponderosa Hall and Whitfield ..............ccccscccccseseeesesesesee ene OoEreacseeec cau tee tel toneeeee 190
5. Right lateral view of a paralectotype. According to the museum label the specimen
is from the upper Helderberg limestone (Lower Devonian), near Dublin, Ohio.
A.M. No. 3093/4. 6. Hinge line view of the specimen seen in figure 5 showing the
ligamental grooves and ridges, (1.5).
“I
i)
weMintilanica lowsiformtsen (Comad))eectrscsee tees ase<eoe eee ee 190
7. View of the upper umbonal region showing the ligamenta] grooves and ridges,
(4x). According to the museum label the specimen is from Hamilton beds (Middle
Devonian), York Center, New York. N.Y.S.M. No. 2830. 8. Right lateral view of
the specimen shown in figure 7.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 41
Plate 42
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
NortH AMERICAN AMBONYCHIIDAE: POJETA
PNBEANAGHION TOR PEA 42
RO VIRVi2) A GAMODUTO TATUM! (GOTT AC! emetic a eater eet tee cere caceetre ee eneene ere ee
nN
aie
|
'
S
12513"
14-17.
19.
20,21.
RRVgitlancamotuy Orisa (COMA) Weems cake citrcesreteresee nce tinvonscctrenenetase aneeesterr errs
Lateral view of a Hall hypotype showing the posterior dentition, (1.5%). According
to the musuem label the specimen is from Hamilton beds (Middle Devonian), Can-
andaigua Lake, New York. N.Y.S.M. No. 2831.
WWE ae Oma OEE (CRON RENG)) —Sececececceecesscocon-Go-pscec Cores ae OLE REPO EERE CEOS aac COREE OSE ePCEO TS
Right lateral view of a Hall hypotype. According to the musuem label it is from
the Hamilton croup (Middle Devonian) on the shores of Seneca Lake, New York.
A.M. No. 5275/2.
Min iilancamowiporannsue (SON Ta di) meee eect setceestcnsccreossscsversctenrtsectrtstetese cess renee eect eee eae
3. Lateral view of a Hall hypotype. According to the museum label the specimen is
from Hamilton beds (Middle Devonian), Bellona, New York. N.Y.S.M. No. 2832.
4. Anterior view of the specimen shown in figure 3.
VM Ar Gamo ull DT IMIS (CONTA )) mreeme errr rceccccst sees ceecteses ac ccescnooovease sonstyrecerestesoe) acess cenncereeneTeeeetees
This specimen is a Hall hypotype. According to the museum label it is from Hamilton
beds (Middle Devonian), Hamilton, New York. N.Y.S.M. No. 2829.
Left lateral view of a Hall hypotype, (1.5). According to the museum label the
spec men is frem the Hamilton group (Middle Devonian), Cayuga Lake, New York.
A.M. No. 5275/1.
MO Pisthoprerama tert ct cally chips: cece sere cee reecenanesav- ce ecese- chen sermentetcneren cateeecsas at eaten cree setae eee
7. Right valve; this specimen is the holotype of O. obliqgua Ulrich. Horizon: White-
water formation (Upper Ordovician). Locality: Richmond, Indiana. U.S.N.M. No.
46270. 8. Dorsal view of the specimen shown in figure 7, (1.5). 9. Anterior view
of the specimen shown in figure 7, (1.5).
MO pisthoplenanraltarmatam iliichy prcsscesccecese-ceesescceeaereccastesacs soon tascerecwsence saan aeornewssecenscesvenes eee eea eae
This specimen is a paratype of O. obliqua Ulrich. Horizon and locality the same as
in figure 7. U.S.N.M. No. 142826.
En OVP USt Lo preramraue enti 2 Cama Chip rernsesecescsstectrsescnieeesnceva-cscestartersensbuasona soaaceetetegesecneerstenetettenetteer
Right lateral view; this specimen is the holotype of O. extenuata Ulrich, (1.5x).
Horizon: Waynesville formation (Upper Ordovician). Locality: Warren County,
Ohio. U.S.N.M. No. 46266.
Opisthoprencw alters claim lili chime ceeeesetercce sree tetteee cents ceeancectnebeeeteneareesn core sereneetenesoencaereneet er
12. Left valve of the paralectotype. Horizon: Waynesville formation (Upper Ordo-
vician). Locality: Waynesvillle. Ohio. U.S.N.M. No. 142827. 13. Anterior view of
the paralectotype.
OpisthopreramallLertat cm Wilrtchipesrertees te sete cnccewereetenrercetavtec cere satetenetnaseasaceetresameateaceneamce tee scerensrc
14. Right valve of the lectotype, (1.5%). Horizon and locality the same as in
figure 12. U.S.N.M. No. 46262. 15. Left valve of the lectotype, (1.5). 16. Dorsal
view of the lectotype, (1.5). 17. Anterior view of the lectotype, (1.5x).
mm Opisthoptenantg Ol dtm UbLUSSCYy) i cseecesceas scesetacsoscencctcatssesccstectns sonceetoeesseeeseots eine eee Pe sea rasare ese
Lateral view of the holotype. Stonington beds (Upper Ordovician), Michigan.
U.M. No. 9854.
Opisthoptera gouldi (GENUS Seva) Secs scesccwesseccececee so trees osu gr sone unsee coneend Saeeaede ou seetesuavecetucesevaapsrose avert
This specimen is a previously unfigured Hussey paratype. Horizon and locality the
same as in figure 18. U.M. No. 9855.
Opisthopbteramonipfinta (ELUSSe ys ear etrese tee eee reese etree esac trent ccrenserserosesmureess
20. Rubber mold of the holotype showing the posterior muscle scars and _ the
posterior lateral teeth. 21. Holotype. Horizon and locality the same as in figure 18.
U.M. No. 9876,
190
190
7190
195
195
195
195
195
195
195
234
Figure
3,4.
5-8.
13%
14,15.
16.
. Opisthoptera casei (Meek and Worthen)
. Opisthoptera casei (Meek and Worthen)
. Opisthoptera casei (Meek and Worthen)
. Opisthoptera casei (Meek and Worthen)
. Opisthoptera casei (Meek and Worthen)
. Opisthoptera casei (Meek and Worthen) ...
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 43
1. Rubber mold of an Ulrich 1893 (1895) hypotype. 2, The original specimen from
which the rubber mold for figure 1 was made. Horizon: Whitewater formation
(Upper Ordovician). Locality: near Lebanon, Kentucky. U.S.N.M. No. 46264.
Opisthoptera casei (Meek and Worthen) .....c.ccccccccsesccseccscseseseeseeesessnerencnenessnseensnecenensceeseansens
3. Rubber mold of an Ulrich 1893 (1895) hypotype of O. fissicosta Meek (see Plate
47, figures 7.8). 4. The original specimen from which the rubber mold for figure
3 was made. Horizon: Waynesville formation (Upper Ordovician). Locality: Clarks-
ville, Ohio. U.S.N.M. No. 46267.
Opisthoptera caset (Meek and Worthen) .........cccccccccccessesecesecesesesenesesesenssnecersesenenssensneneeenenees
5. Anterior view of an Ulrich 1893 (1895) hypotype. Horizon: Whitewater formation
(Upper Ordovician). Locality: Richmond, Indiana. U.S.N.M. No. 46265. 6. Dorsal
view of the specimen shown in figure 5. 7. Left valve of the specimen seen in
figure 5 showing the midumbonal ridge. 8. Right valve of the specimen shown in
figure 5.
9. Anterior view of an Ulrich 1893 (1895) hypotype. Horizon and locality the
same as in figure 5. U.S.N.M. No. 142828. 10. Left valve of the specimen shown in
figure 9. 11. Dorsal view of the specimen seen in figure 9 showing the bifid an-
terior byssal retractor scar in the left valve.
Anterior view of a specimen showing the discontinuous pallial line with its small
closely spaced areas of attachment. From Richmondian rocks (Upper Upper Or-
dovician), Preble County, Ohio. U.S.N.M. No. 101671.
Opisthoptera casei (Meek and Worthen) .........s.:ccsscscssssecessessseecseeceetccceseeeeecseersosencesencansnecess
Left lateral view of an Ulrich 1893 (1895) hypotype showing ligamental remains.
Horizon and locality the same as in figure 5. U.S.N.M. No. 142829.
Opisthoptera casei (Meek and Worthen) .......c.cccccccssssesececscseceercesrerececessececsseecsscerenenascneseasenens
14. Anterior view. Horizon: Clarksville member, Waynesville formation (Upper
Ordovician). Locality: Sewell’s Run, 0.3 miles east of Clarksville, Ohio. U.C.M.
No. 35900. 15. Right valve of the specimen seen in figure 14 showing the midumbonal
ridge.
Opisthoptera casei (Meek and Worthen) ...........scccssesssssssssscsssrececssecncnsestecucnsceceencnsonssecoensness
Rubber mold of a young specimen showing relatively little costellal subdivision.
Horizon and locality of the original specimen the same as in figure 14. U.C.M. No.
35892.
Right valve. Horizon and locality unknown. M.U. No. 76T.
18. Left valve. Horizon: Whitewater formation (Upper Ordovician). Locality: road-
cut 2 miles south of Richmond, Indiana, on new Indiana route 27. U.C.M. No. 35893.
19. Right valve of the specimen shown in figure 18. 20. Anterior view of the specimen
shown in figure 18, (1.5). 21. Dorsal view of the specimen shown in figure 18,
(GIES Hye
22
44.
Rubber mold of the specimen seen in figure 23 showing the posterior muscle
scars and the midumbonal ridge. 23. The original specimen from which the rubber
mold for figure 22 was made. Horizon and locality the same as in figure 18. U.C.M.
No. 35881.
193
193
193
193
193
193
193
193
co
Plate 4
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 44
Figure
3,4.
5,6.
7,8.
10,11.
14-16.
. Opisthoptera casei (Meek and Worthen)
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 44
Opisthoptera caset (Meek and) Worthen) scececsstssccsesiesscscececvessececees-toveveresererncncscecrasenanesesthenes 193
Rubber mold of a specimen from the Clarksville member, Waynesville formation
(Upper Ordovician), Stony Run, downstream from the crossing of Middleboro
Road, between Ohio routes 350 and 22, (1.5). U.C.M. No. 35890.
miOpisthoprera caser (Meek and) Worthen) secrete sccecsessecestecessccteeecnsssecceceveee-cocccenaetetnecnstaeseeneszes 193
Rubber mold of a specimen from the Clarksville member of the Waynesville forma-
tion (Upper Ordovician), Bull Run Creek, south of Oxford, Ohio, (1.5%). U.C.M.
No. 35889.
Opisthoprenaicasem (Meek andi Worthen) ccs -cscsreccceserer-scescesessancneccarex:cocececsnesceacuspreceaettsarteraece 193
3. Rubber mold of the specimen shown in figure + (see Plate +7, figures 5-6). 4. The
original specimen from which the rubber mold for figure 3 was made. Horizon:
Clarksville member of the Waynesville formation (Upper Ordovician). Locality:
Stony Hollow, Clarksville, Ohio. U.S.N.M. No. 70459.
ODisthoprar, aEspeOles PACBNEW/S PECIES iatceecestcccentenessccaparanase nenantensestseactdteasracesscceveltosetrrssesrectr ae 195
5. Anterior view, (1.5%). Horizon: Elkhorn formation (Upper Ordovician). Locality:
New Point Stone Company Quarry, 0.5 miles north of New Point, Indiana, on road
800E. U_C.M. No. 35899, 6. Left valve of the specimen shown in figure 5.
Opicthopienamspecies Aww ewes PECLES itcsscccssererecrecrenes sees enesacecenartere searestncncecrerttentrameneecenerenestanes 195
7. Right valve showing the posterior muscle scars and posterior lateral teeth. Hori-
zon: Elkhorn formation (Upper Ordovician), immediately below the contact with the
Brassfield formation (Lower Silurian). Locality: outcrop on Indiana route 46, just
past the intersection of route 46 and County Line Road, west of Batesville, Indiana.
U.C.M. No. 35883. 8. Anterior view of the specimen shown in figure 7 (1.5x).
> OFGWAO/NOAA OASIS JN, TET QNEES accoccencecocepecencocuccn cence eebonrto neentectureneckensorccopct ocosaoaceorcpnepacce 195
Left valve. Horizon and locality the same as in figure 7. U.C.M. No. 35894.
Opisthoprejaucaseie (Nleeksand mVVOrthen)) feces sscesssrerncanteaterenccticesascnctraepactsiverecereuesreresearearstcnes 193
10. Dorsal view of a specimen showing remnants of the anterior byssal retractor
muscle scars, (1.5). Horizon: Whitewater formation (Upper Ordovician). Locality
unknown. M.U. No. 82T. 11. Right valve of the specimen shown in figure 10.
MO pistnopienamcas ene (Nicekmand SVVOLthen)) |csce-crscscceccecconcosssasturcatersrceestsastscncannneneestaryanrante ameter 193
Enlargement of figure 12, Plate 43, (2).
193
Right valve of a specimen showing posterior lateral teeth. Horizon: Whitewater
formation (Upper Ordovician). Locality: roadcut 2 miles south of Richmond, Indiana,
on new Indiana route 27. U.C.M. No. 35895.
Opisthoptera casei (Meek and Worthen) ee
14. Dorsal view, (1.5). Horizon and locality the same as in figure 13. U.C.
35886. 15. Left valve of the specimen seen in figure 14 showing remnants of the
posterior muscle scars and the pallial line. 16. Anterior view of the specimen seen
in figure 15 showing pallial line remnants, (3).
236
Figure
1.
7-10.
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 45
Opisthopteravcascie(Meckwandavyjorthen)) ierreesccescteser: aecececerraeerenctuces artcerassanasnenesstaemeanesernenetin
This specimen shows remnants of the ligamental structures, (1.5%). Horizon:
Clarksville member, Waynesville formation (Upper Ordovician). Locality: Sewell’s
Run, 0.3 miles east of Clarksville, Ohio. U.C.M. No. 35884.
wOpisthoptera case (Meeks andmvyonthem))jcctreseecconcstenestescerreracstesetcccesaserecacncesmeceererees oseeeeasa
A spec'men showing almost the entire shell outline. Horizon and locality unknown.
M.U. No. 77T.
miOpisthoptena casei (Nieeksran devo rthen!) ecersce-ceerertecstterartesesteeereteesserannn nan arenes tases acess
Left valve of a specimen showing the posterior muscle scars. Horizon: Whitewater
formation (Upper Ordovician). Locality unknown. M.U. No. 81T.
~Opisthopteracases (IMeekmandeswiorthem)) \sececccsstacccesccecctesseesseeecseccrerseeeeceretstteeemeetttaseneonsern
Rubber mold of a specimen showing almost the entire shell outline and the posterior
muscle scars. The original specimen from which the rubber mold was made is from
the Whitewater formation (Upper Ordovician), Richmond, Indiana. U.C.M. No.
35885.
MOpisthopteraucaser (Meek sande wourthen))) sescesectscccteseeceecteteestrercres tenet are teameteerececurwncrertentines
External mold showing the shell prosopon, (1.5%). Horizon and locality the same as
in figure 1. U.C.M. No. 35882.
~Opisthoptena casen (Meek and) Worthen) ccccscseeescccecs-srercescaresecececesesesecesesencererrsartceseteceaerncereaets
External mold showing the shell prosopon, (1.5%). The museum label lists this speci-
men as from the Arnheim formation (Upper Ordovician). No other specimen of
Ophistoptera has been reported from this formation and the presence of the genus
therein needs corroboration. Locality unknown. M.U. No. 67T.
Palaecardia cor diporinis meal seecce cee tee eee ee eT
7. Right valve of the holotype. Niagaran (Middle Silurian), near Milwaukee,
Wisconsin. A.M. No. 2070. 8. Left valve of the holotype. 9. Anterior view of the
holotype. 10. Posterior view of the holotype.
193
193
193
193
193
196
e 45
Plat
ANA, VOL. V
IRIC
PALAEONTOGRAPHICA AMI
e
Es
wpe
ete
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 46
Figure
1-5.
10.
ile
NortH AMERICAN AMBONYCHIIDAE: POJETA
EXPLANATION OF PLATE 46
Psilomychiampanangilatamullinichcmeere ne ccctetec tc ersrcer eccerece eaten ee earersenrecrseeee eee
1. Left lateral view of the holotype. Horizon: Corryville member, McMillan forma-
tion (Upper Ordovician). Locality: Cincinnati, Ohio. U.S.N.M. No. 46287. 2. Left
lateral view of the holotype. This photograph was taken without whitening the
specimen with a sublimate of ammonium chloride. The dark upper umbonal region
is covered with a beeswax-like substance. Also note the inked-in features. 3. Anterior
view of the holotype; the photograph was taken without whitening the specimen. 4.
Anterior view of the whitened holotype. 5. Hinge line view of the holotype, (1.5).
. Psilonychia perangulata Ulrich ........ Hat acu avant nave audeesberencst odes ESETEa Ga aih Sta songs dat ap otagrasesaameeteeee sees
Anterior view of a paratype showing the byssal gape and concentric growth lines.
Horizon and locality the same as in figure 1. U.S.N.M. No. 142830.
eODisiopierarcasen(Nleeks and avVorth en) iererereccssscrcecetenesescestere so rsesesoneaes eeneeenceeee meter ene
Rubber mold of a specimen showing the prosopon, (1.5). The original specimen
from which the mold was made is from the Clarksville member, Waynesville forma-
tion (Upper Ordovician), Sewell’s Run, 0.3 miles east of Clarksville, Ohio. U.C.M.
No. 35888.
MeO PINCH OPLeras ra L pla Wilms Chimtrestecsereseretet coe tec cere ere ate teckan occ aatewon sa coostnest tr eract tree ene erence eetees
Lateral view of the holotype. The species is not regarded as belonging to Ofisthop-
tera. Horizon: Bellevue member, McMillan formation (Upper Ordovician). Locality:
Cincinnati, Ohio. U.S.N.M. No. 46263.
Paes OPUSTHO PICT acai] att COSTAL a Ulli chi mercreeseaceteor act sc sss aaeste core anen eos ieacenssaeceonte ts ctte-eraese?ssagetensoceten
Right lateral view of the holotype. The species is not regarded as belong to Opisthop-
tera. Horizon: Waynesville formation (Upper Ordovician). Locality: near Waynes-
ville, Ohio. U.S.N.M. No. 46268.
SOPUStOPLEN a rcOLAU Lids: MUM TIGL Mert ecrest ciecesecse teeese et tec nceec toe ee xcs te coterie rack sctete sas eT nee
This specimen is the holotype. The species is not regarded as belonging to O/pis-
thoptera. Horizon: Fairmount member, Fairview formation (Upper Ordovician).
Locality: Cincinnati, Ohio. U.S.N.M. No. 46269.
COV AIGI OIRO FDI AATIG? AUNTS ecesreepececen- tren cco eacer eecen: ooecbescennacacee necro sncec Ope onoecbceecoroeceE CLE CEOS
This specimen is a paratype. Horizon and locality the same as in figure 10.
U.S.N.M. No. 142831.
193
193
193
193
Figure
ile
23%
5,6.
PALAEONTOGRAPHICA AMERICANA (V, 36)
EXPLANATION OF PLATE 47
Ambomychia alata Neel cceccrececscssccessernenencnenesererscteenes ae tooas etecer meat eae cance sc eee ten rere ec eeoee eee
Enlargement of the posteroventral area of the specimen seen in figure 17, Plate 30,
showing the weathering off of the fine growth lines from the raised costae, (6X).
Byssopteria radiata FLA) ..cc.cs.cc.csssscsescescsecsecvesessucsesteccsersenectcniecnssnsetcnesnistsrsss sarvervecenesersenssnaees
2. Enlargement of the posterodorsal portion of the specimen seen in figure 7, Plate
32, showing intercalated (right-hand facing arrow) and subdividing (left-hand
facing arrow) costae, (3%). 3. Natural size view of the specimen shown in figure
2. The arrows indicate the same points of costal increase.
. Byssopteria radiata Hall .....ss.sscccccesssessesscssessecnesessenecncsssensssecnsssaneccevesscetessente cacrscaserestecuestecnerecs
Enlargement of the posterocentral area of the specimen seen in figure 4, Plate 32,
showing some costal increase (arrows), (2X).
Opisthoptera casei (Meek and Worthen) -......cc:cccccsecesecsessseessesessessecsssssecsnscnsessessscensenneates
5. Enlargement of the upper posterior umbonal slope of the rubber mold seen in
figure 3, Plate 44, showing costellal bifurcation (short arrow) and trifurcation (long
arrow), (2X). 6. Further enlargement of the specimen shown in figure 5. The
arrows indicate the same points of costellate increase. (4.5X).
. Opisthoptera casei (Meek and Worthen) .......ccccceecsessececsessecsess ees essecsesecnsssececeneetecnsetseitenes
7. Enlargement of the lower umbonal area of the rubber mold seen in figure 3, Plate
43, showing costellal bifurcation (short right-hand facing arrow), trifurcation (long
right-hand facing arrow), and intercalation (left-hand facing arrows), (2X). 8.
Further enlargement of the specimen shown in figure 7. The arrows indicate the
same points of costellate increase, (4+).
175
193
193
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 47
INDEX
NUMBER 36
Note: Light face figures refer to the page numbers. Bold face figures refer
to the plate ere
A carinata, Mytilarea 188
acutirostra, Ambonychia 187 casei, Ambonychia 192, 194
| Mytilarca 37 187 Megaptera 169, 192-193
_ acutirostris, Ambonychia 159-160, 182 Opisthoptera = 43-47 193-196
Byssonychia 182 casteri, Ambonychia 136, 200
affinis, au bonschiepsis 22 162-163 Cedarville dolomite 138
Ahtioconcha 179 Chapman sandstone 190
alata, Ambonychia 29-32, 47 138, 145, 150, 170, 172-174, 192 chemungensis, Inoceramus 186
Anomalodonta 170, 172-173 Mytilarca 37-38 150, 186, 188, 191
Proptera 138 China 141
Alation 138 Cincinnati, Ohio 145, 154, 158, 197
Allonychia 19-21 136, 138, 147, 153-154, 156-160, 178, 199-200 cingulosa, Mytilarca 38 189
alternata, Opisthoptera 42 193-195 Cleidophorus 147
Ambonychia 29-32 138-147, 149-150, 152-156, 160-162, 164, Cleionychia 32-34 141, 146-147, 149, 153-155, 161-162,
171-174, 181-182, 184, 187, 191-193, 196, 200-201 : ; 176-181, 199
151 Clionychia see Cleionychia
135, 152 Colorado __ 4 187
Ambonychinia 147, 149, 161-162, 177, 199-200 concordensis, Maryonychia 36 138, 185
Ambonychiopsis 21-24 136, 140-141, 147-148, 153-155, 157, Opisthoptera 185, 193
160-165, 172, 177, 180, 199-200 Congeria 148
amii, Mytilarea 187 Congeriomorpha 136, 140-141, 148, 153, 155, 157, 159, 181,
Amphicoelia 24-25 136, 138, 140-141, 143, 147-148, 153-155, i 199-200
162, 165-169, 187, 196, 200 contempta, Dvorecia_ 153
ampla, Opisthoptera 46 193 cordata, Lophonychia 184
amygdalina, Ambonychiopsis 22 163-164, 180 cordiformis, Mytilarea 189
andrusovi, Congeriomorpha 181 Palaeocardia 45 196
Angellum 153 Corryville member 158, 197
angusta, Anoptera 29 171-172 costata, Ambonychia 169, 173, 174
Cleionychia ilzaley alg} Amphicoelia 167
Anomalocoelia 149, 153, 162, 199 Covington, Kentucky 159
Anomalodonta 25-29 140-149, 153-154, 169-171, 181-182, creba, Cleionychia 180
193, 199, 201 crenata, Eridonychia 35 182
Anoptera 28-29 141, 153-154, 162, 171-172, 181, 199 crispa, Cleionychia 180
Antarctica 191 cultellata, Lophonychia 184
Anticosti Island 189 Mytilarea 189
aphaea, Mytilarca 40 187-188 cultrata, Ambonychia 32 145, 174
apicalis, Eridonychia 34 181-182 cuneatus, Mytilarca 40 188
Arca 143 curta, Cleionychia 178
Archaeocardia 196 curvata, Ambonychiopsis 162, 164
Ardennes : 141, 183, 187, 190 Cynthiana formation 154, 157, 159, 178
arenacea, Mytilarca 40 189 Cyrtodontopsis 183
Arizona 155, 181 Czechoslovakia 154
Arnheim formation 169, 173
Atomodesma 148, 155-156 D
attenuata, Cleionychia 34 180 Dalarna, Sweden 154, 187, 197
Mytilarca 188 dalhousei, Mytilarca 38 145, 150, 189
Auburn chert 179 Demanetia _ 153-154
Australia 155, 190-191 dentata, Mytilarca 189
Avicula 168 Dermatostroma 141
devonica, Gosseletia 183
B Dollo’s Law 136, 199
Belgium 141, 154, 190 dubia, Mytilarca 40 189
bellistriata, Ambonychia 160-162, 165, 172 Dvorecia 153-154
Ambonychiopsis 21-22, 24 163-164
Boda limestone 154 E
Bokkeveld beds 175 Ectenoptera 135, 153-154, 181, 193
Brassfield limestone 188 eduliformis, Mytilarca 38 188
brevirostris, Allonychia 155, 157 edulis, Mytilus 159
byrnesi, Ambonychia 142 Ekwan River 188
Byssonychia 135, 153-154, 160-162, 172, 181, 193 Elasmodophora 153, 162, 199
Byssopteria 32, 47 141, 152-153, 155, 174-176, 184-185, 201 Elkhorn formation 195
Ellesmere Land 191
Cc elroyi, Ambonychia 138
Canada 162-164, 187 Enkebergia 153
canadensis, Mytilarca 189 Eopteria 153
cancellosa, Ambonychia 176-179 erecta, Cleionychia 33 178-179
Canoe Camp, Tioga County, Pennsylvania 174 Eridonychia 34-35 135, 153-154, 156, 181-182, 193
Cardium : ; 196 Estonia 154, 179
INDEX
Buchasma 153 Lexington, Kentucky 157, 159 |)
excavata, Cleionychia 32 178 Liebea 155
extenuata, Opisthoptera 193, 195 Lima 147 |
Lime (Plicacesta) : 139 |
F Limoptera 152-153
Fairmount member 159, 182 Liu Koping, China ... ‘ 141,155
Fairview formation 159, 182 lodanensis, Demanetia 153
fibristiataeMytilanea 39 187, 190 Lophonychia 36 136, 140, 147, 153, 155, 184, 189-191, 200
fissicosta, Ambonychia 193-194 Lunulacardium : : - 153
flanaganensis, Allonychia 19-21 138, 148, 157-159 Luxembourg 141, 190
foerstei, Mytilarca 37 138, 188 Lyriopecten 168
Follmannia 35 141, 153, 155, 184, 201 Lyrodesma 151
France 141, 190
? M
G macroptera, Ambonychia : 155
Cenneny 141, 154, 183, 187,190 Maine aU
gibbosa, Cleionychia 179 M Hob 1
Mytilarca 39 189 Mansfield Tioga County, Pennsylvania Bas ie
oj ‘s 2 s PE) Se )
gigantea, Anomalodonta 25-29 138, 142 Do acorn 1 margaritifera, Pinctada 142, 145-146
Gosseletia 95-36 136, 149, 143, 146, 149-150, 152-158, 155, ™arginalis, Cleionychia ee
157, 182-184, 190-191, 199-201 aaa [a =) ;
Gosseletia (Gosseletia) 183 eae Mytilarca Beat
letia (St ee aay ;
Gosselc ie (Siappersel) 133 Maryonychia 36-135, 140-141, 153-154, 176, 185, 193, 201
gouldi, Opistholoba iSi,dosios., -Sehiliangtormation seoaeee
Opisthoptera 42. 195 Mesambon ‘ aa 1525 5p els9)
iffini. A | : egaptera 73, 185, 192-193
Seana odonta Le eneige Michigan 155, 169, 171, 178, 183-184, 193, 195-196
illersburg phase ; 159
H See a ; 154, 162-165, 179-180
halfari, Cyrtodontopsis 183 queen sa ae 7829 e es at
Gosseletia 183 Modiella 153
i Modiolus : Be. : 138, 142, 146
ae montrealensis, Cleionychia 179
illinois 162-163, 165, 167-168, 187 Moracco 155
illinoisensis, Ambonychia 165 Myalina ; 152, 168, 188, 190
«diana 135, 156-158, 167-169, 171-172, 174, 178, 182, 185, Myalinopterella ; 153-154
ae 187-188, 193-195 Mytilarea 37-42 141, 143, 152-156, 162, 178, 181, 184-191,
inflata, Mytilarea 189 196-197, 199
intermedia, Ambonychia 138 Mytilarca (Mytilarca) 186
Towa ¢ 175 Mytilarca (Plethomytilus) 186
Ireland 154, 178, 180 mytiliformis, Mytilarea 188
Island Mesa beds 181 mytilimera, Mytilarca 189
5 my iloides, Cleionychia ; 34 179
ytilops 153
James Bay 188 Mytilus : 136, 138, 142, 146-147
jamesi, Allonychia 19 138, 152, 157-158
Megambonia 57, ; f N
jessieae, Mytilarca 39 187, 190 nantanensis, Plethomytilus : 190
Joachymia 153 Nethorstella se 153-154
neglecta, Amphicoelia ; 24-25 167-169
K Nevada 187-189
Kazakastan 178, 180, 190 New Brunswick 189
Kentucky 135, 154, 156-158, 169, 171-172, 174, 178, 182, 185, New eee ie 188
193-195 ew South Wales 1555) 19
Kimmswick limestone 163 New York 154-155, 162-164, 167, 179-180, 183-184, 187-190
knappi, Mytilarca 189 nitida, Ambonychia 178, 189
Korea 155, 178, 180 Cleionychia 33 179
Kullsberg limestone 154 Mytilarea ; 28 179, 188-190
kiitsingensis, Ambonychia 155 Norway : 154, 178, 180
i notes Opin : 46 193
va Scotia ‘ 187
Lake Church formation 155, 184 Nueuts 143
Lamellodonta 197 uculites : 147
lamellosa, Ambonychia 176-178
Cleionychia 33 142, 148, 179-180 2 ©
lata, Mytilarea ; 39 189 obesa, Ambonychia ; 31 141, 174
laticostata, Opisthoptera 46 193 obliqua, Mytilarca , 188
leidyi, Amphicoelia 24-25 148, 167-169 Opisthoptera : 193, 195
Leptaena limestone 154, 187, 197 occidentalis, Byssopteria ; ; 175
Leptodomus 166-167, 169 Mytilarea 39 187, 190
240
Ohio
Ontario
Opistholoba
Opisthoptera
INDEX
135, 138, 154-158, 167, 169, 171-172, 174, 182-185, 188,
190, 193-195
154, 167-169, 171-172, 179-180, 188, 190, 193-194, 196
135, 153-154, 156, 191
42-47 138, 140-144, 146-148, 153-154, 156,
169-170, 173, 176, 181, 184-185, 191-196, 199, 201
orbicularis, Ambonychiopsis
Pterinea
orbiculata, Amphicoelia
Avicula ;
orbiculatus, Lyriopecten
orbiculoides, Lyriopecten
Oriskany formation
orsae, Mytilarca
osmundsbergensis, Ambonychiopsis
Ottawa formation
ottawaensis, Cleionychia
ovata, Allonychia
oviformis, Cleionychia
Mytilarca
Palaeocardia
Paramytilarca
Paris, Kentucky
paucicostata, Eridonychia
pediculata, Ambonychinia
Pennsylvania
perangulata, Psilonychia
percarinata, Mytilarca
pernoides, Mytilarca
pexata, Anadara
planistiata, Ambonychiopsis
plausibilis, Plethomytilus
22-23 138, 163-164
164
168
168
168
168
190
150
160
163-164
179
21 159-160
155, 180
41-42 136, 138, 190
45 153-154, 156, 196, 201
149, 153, 162, 199-200
157, 159
34 182
143
155, 160, 174, 188-189
46 196-197
190
188
145
23 162-165
190
Plethomytilus 135, 153-154, 156, 186, 188-191, 196
Plicacesta 139
plicata, Anomalodonta 170-171
Poland 187, 190
ponderosa, Mytilarca 40-41 138, 190
Praeanomalodonta 153, 162, 199
praecursor, Cyrtodontopsis 183
Modiomorpha 183
Prosopon 140
Prothyris 187
pseudalectryonia, Follmannia 141, 150, 183
pseudalectryonia, Gosseletia seen JB
Psilonychia 46 141, 153-155, 162, 196-197, 199
Pteria 138
Pteriina 151
Pterinea 183
Pterioida 151
Pteriomorphia 151
Pterochaenia 153
Pyanomya 153
pyramidata, Mytilarca 38 190
pyrimadata, Mytilarea 38 190
Q
quartzitica, Cyrtodonta 183
Cyrtodontopsis 183
Quebec 178-179, 188-189
R
radiata, Ambonychia 144-145, 150, 161, 172, 174
Ambonychinia 148
Byssopteria 32, 47 175
Mytilarea 174
regularis, Mytilarca 38 189
retusa, Gosseletia 183-184
rhomboidea, Cleionychia 179
rowei, Mytilarca 190
Russia
154
24]
S
Schoharie grit 189-190
Scotland 154, 168, 178, 180, 187, 190
Selenimyalina 155
septentrionalis, Ambonychia 165
Septifer 148
Septimyalina 155, 201
semiplana, Byssopteria 175
Siberia 187, 190
sigilla, Mytilarca 37 138, 188
Siliqua 147
simplex, Mytilarea 39 189
South Africa 155) ke
Spain 154, 183
Stappersella 149-150, 153, 183-184, 199-201
Stenothecoides 197
Stonehouse formation 187
Streptomytilus 138, 145, 150, 153-154, 156, 186-188, 191, 197
suberectus, Mytilarea 39 190
subovalis, Cleionychia 180
subquadrata, Cleionychia 180
Myalina 152
subrotunda, Allonychia 21 159-160
subundata, Cleionychia 32 178
superba, Cleionychia 178
Sweden 154, 178, 190
T
Tennessee 167, 174
Tioga County, Pennsylvania 175
trabeculum, Atomodesma 156
transplicata, Amphicoelia 167-168
transversa, Cleionychia 180
trechmanni, Atomodesma 155
triangularis, Cleionychia 180
trigonale, Lophonychia 36 138, 184
Mytilarea 184, 190
triquetra, Gosseletia 35-36 183-184
Mytilarea 190-191
triton, Amphicoelia 168
Avicula 168
U
ulrichi, Ambonychia 31 174
Amphicoelia 168
Psilonychia 197
umbonata, Mytilarea 38 189
undata, Ambonychia Wu
Cleionychia 34 177, 180
undulata, Ambonychinia 161
undulatus, Ambonychia 23 165
Vv
Vanuxemia 179
Venezuela 155, 157
Victoria 191
Virginia 188
Volsella 146
WwW
wabashensis, Mytilarca 188
Streptomytilus 197
Waynesville formation 169, 172, 174, 182, 185, 194-195
West Virginia 167-168
Whitewater formation 172, 194-195
Winchester, Kentucky ; 157, 159
Wisconsin 154-155, 165, 167-168, 179-180, 184, 187, 189-190, 196
woodi, Atomodesma 155
woodmani, Palaeocardia 196
ny,
Yunnan, China 155
SXONSNG Vi Gn (INO8s01 55-160) 501412 pps 055i Pl Sek cceccceccecascsserccsesesececassccecesscscscacsese
Globotruncana in Colombia, Eocene fish, Canadian-Chaz-
yan fossils, foraminiferal studies.
EXOKON WA De (INOS OL OL=164) lo) 4 8OiDPigii5iZs DISs lecsscccerescescetsocesteeancecssosouceccecsesesesere
Antillean Cretaceous Rudists, Canal Zone Foraminifera,
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can-European species, Puerto Rico forams.
DX oe (INGOs 1184) 99 Gi Dest Limp lencceceoveseessncscosesesesseostaroccesrosesorczosevtesecceesvae
Type and Figured Specimens P.R.I.
CT (Nos 0185-192) ke S80 ppe soiplss cease anne,
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Ga. forams. Newcomb mollusks, Wisconsin mollusk
faunas, Camerina, Va. forams, Corry Sandstone.
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Venezuela Cenozoic gastropods.
XOGIE TS A (INoenl 942198) SA 2 7p psy) 39. PIS i toc-cccvacecucacnasevaseresccescssssouesessesvoesseee
Ordovician stromatoporoids, Indo-Pacific camerinids, Mis-
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SEW 2 (Noe:2 199-203). 365app:. 68eplss a “5
Puerto Rican, Antarctic, New Zealand forams, Lepidocy-
clina, Eumalacostraca.
EXT Ve (INO32204) 5, 9564) DD5363) PIB) cccscetesconccsssverevceossussesespescsparrncsoxssenaceesees
Venezuela Cenozoic pelecypods
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Wea CNOS3 225-228) AO SMP Psy 27 o/DISs. cocesssnsevcesrvavsivestsctsvesssecesccousesseccteteee
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UPPER CRETACEOUS PLANKTONIC FORAMINIFERA
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1967
Paleontological Research Institution
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AUG 18 1967
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BULLETINS OF AMERICAN PALEONTOLOGY
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UPPER CRETACEOUS PLANKTONIC FORAMINIFERA
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ACKNOWLEDGMENTS
This project was supported primarily by a grant of
funds (NSF G-18643) from the National Science Founda-
tion, Washington, D.C.
Additional funds were obtained from the Department
of Geology, University of California, Davis, for the subsidy
of several plates. The writer is indebted to Dr. Cordell
Durrell, Chairman, for his help in this matter.
The writer is greatly indebted to Michael D. Piburn
for his able assistance during the course of field work in
Mexico and to David D. Nixon for his able assistance during
the course of field work in Texas.
Particular thanks are due to Mrs. Winifred Madison,
Mrs. Lynn Rudy, and Raymond Roberts for the preparation
of excellent drawings of the Foraminifera and to Mrs.
Meryllene Smith for her care in typing the manuscript.
Ing. Guillermo P. Salas, Director of the Geological
Institute, University of Mexico, was greatly instrumental in
orienting the writer for field work in Mexico. Without his
aid, field work in Mexico would not have been nearly as
successful. The writer is also indebted to Ing. E. Lopez-
Ramos and Petroleos Mexicanos, Mexico, D.F., for supply-
ing geologic base maps useful in the present study. Through
the kindness of Dr. F. Bonet and Petroleos Mexicanos, the
writer obtained important Méndez core samples from Petro-
leos Mexicanos well, Bustos no. 1. These samples have
played an important role in the interpretation of the bio-
stratigraphy of the Méndez shale in the area surrounding
‘Tampico.
The writer is greatly indebted to William A. Jenkins,
Jr., director of the Socony Mobil Oil Company, Field Re-
search Laboratory, Dallas, Texas, for allowing him to col-
lect numerous samples from Socony Mobil’s Dallas and
Waco cores of the Eagle Ford group. He is likewise indebted
to Chas. W. Brown, R. L. Pierce, and Stephen Percival
(Socony Mobil Field Research Lab.) for their aid in
sampling the above Eagle Ford cores. Numerous samples
from the Navarro, Kincaid, and Grayson formations were
also supplied to the writer by the Socony Mobil Field Re-
search Laboratory.
Kenneth Seewald and Keith Young of the Department
of Geology, University of Texas, were helpful in guiding
the writer in his sampling of the Austin chalk in its type
area at Austin. Without their help many significant expo-
sures of the Austin chalk at Austin would have undoubt-
edly been overlooked.
Thanks are also due to Richard Cifelli, U.S. National
Museum, Washington, D.C., and Katherine V. W. Palmer,
Paleontological Research Institution, Ithaca, New York,
for allowing the writer to examine important type speci-
mens in the collections under their administration. Dr.
Cifelli, in particular, loaned numerous type specimens for
the writer to examine and illustrate in this monograph.
Ruth Todd (U.S. Geol. Survey) ; Joseph E. Hazel
(U.S. Geol. Survey); Z. R. El-Naggar (Univ. Riyadh,
Saudi Arabia) ; H. Luterbacher (Geol.—Pal. Instit., Univer.
Bernoullianum) ; Jacques Sigal (Institut Frangais du Pé-
trole) ; William W. Hay (University of Illinois) and W.
Storrs Cole (Cornell University) kindly supplied the writer
Upper Cretaceous samples or specimens pertinent to this
study. John Imbrie informed the writer of the status of
type specimens in the White Collection at the Department
of Geology, Columbia University. His patience and efforts
are greatly appreciated.
Discussions with a number of colleagues during or pre-
vious to this study have greatly enhanced the writer’s work.
Foremost among these colleagues are R. K. Olsson (Rutgers
University) ; W. A. Berggren (Woods Hole Oceanographic
Institution) ; Paul Bronnimann (Institut de Géologie de
l'Université Genéve); Noel Brown (Humble Oil and
Refining Company) ; Hans M. Bolli (Geologisches Institut,
Zurich) ; A. R. Loeblich, Jr. (California Research Corpora-
tion) ; and Stephen Percival (Socony Mobil Oil Company) .
Finally, the writer is indeed indebted to D. O. Emerson,
Department of Geology, University of California, Davis, for
programing his form analysis data for statistical computa-
tions on the IBM 7040 computer.
CONTENTS
Abstract
Acknowledgments
Introduction
Thin-sectioning planktonic Foraminifera
Form analysis of Upper Cretaceous planktonic Foraminifera
Nature of biostratigraphic units used herein
Classification
Systematic paleontology
Superfamily Globigerinacea
Family Heterohelicidae
Subfamily Guembelitrinae
Genus Guembelitria
Subfamily Heterohelicinae
Genus Heterohelix
Genus Gublerina
Genus Pseudoguembelina
Genus Pseudotextularia
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St Ot 00 OOOOH
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Genus Racemiguembelina 70
Genus Planoglobulina 71
Family Planomalinidae 73
Genus Hastigerinoides 273
Genus Globigerinelloides 274
Family Schackoinidae 279
Genus Schackoina 279
Family Rotaliporidae 280
Subfamily Hedbergellinae 281
Genus Hedbergella 281
Genus Clavihedbergella 285
Genus Praeglobotruncana 286
Subfamily Loeblichellinae, n. subfamily 288
Genus Loeblichella, n. genus 288
Subfamily Rotaliporinae 289
Genus Rotalipora 289
Family Marginotruncanidae, n. family 298
Genus Whiteinella, n. genus 298
Genus Marginotruncana 299
Family Globotruncanidae 314
Genus Archaeoglobigerina, n. genus 315
Genus Globotruncana 318
Genus Rugoglobigerina 564
Genus Rugotruncana 368
Family Abathomphalidae, n. family 37]
Genus A bathomphalus 371
Genus Globotruncanella 372
Appendix 375
Sample preparation 375
Illustration of specimens 375
Location and description of microfossil samples mentioned in text 375
Mexico 375
Texas 377
Southwestern Arkansas 380
Puerto Rico 380
Miscellaneous 381
Bibliography 381
Plates 387
ILLUSTRATIONS
TABLES
Page
1. Criteria for classification 252
2. Standard deviations and means of
form analysis measurements
Between 336, 337
A.
B.
ot
ba I
[2:
PEXN'T-FIGURES
Schematic diagram showing line formed by the interesection of the plane
of section with the spiral surface of the test
Form analysis measurement of a vertical (axial) section of a planktonic
Foraminifera having a keeled, pseudocarinate, or acutely angled periph-
ery
Index Map
Upper Cretaceous correlation chart Between 252,
Range zones and relative abundance of Upper Cretaceous Heterohelici-
dae. Faunal composition of assemblage zones, subzones and zonules
Range zones and relative abundance of Upper Cretaceous Planoma-
linidae, Schackoinidae, and Abathomphalidae. Faunal composition of
assemblage zones, subzones, and zonules.
Range zones and relative abundance of Upper Cretaceous Marginotrun-
canidae, Globotruncanidae, and Abathomphalidae. Faunal composition
of assemblage zones, subzones, and zonules
Phylogenetic relationship of Upper Cretaceous Globigerinacea at the
family level
Phylogenetic relationships of Upper Cretaceous Heterohelicinae at the
generic level
Phylogenetic relationships of Upper Cretaceous Planomalinidae at the
generic level
Phylogenetic relationship of Upper Cretaceous Rotaliporidae at the
generic level
Schematic plot of Rotaliporid size versus Cretaceous time
Form analysis data for Rotalipora appenninica (O. Renz)
Form analysis data for Rotalipora cushmani (Morrow)
Scatter plot of T’X/TX and D-D’/U-U’ values for R. appenninica (O.
Renz) and R. cushmani (Morrow)
Scatter plot of T’X/TX and D-D’ values for R. appenninica (O. Renz)
and R. greenhornensis (Morrow)
Form analysis data for Rotalipora evoluta Sigal
Form analysis data for Rotalipora greenhornensis (Morrow)
Form analysis data for Rotalipora thomei Hagn and Zeil
Form analysis data for Marginotruncana angusticarenata (Gandolfi)
Form analysis data for Marginotruncana bouldinensis, n. sp.
Form analysis data for Marginotruncana concavata (Brotzen)
Form analysis data for Marginotruncana marginata (Reuss)
Form analysis data for Marginotruncana indica (Jacob and Sastry)
Form analysis data for Marginotruncana renzi (Gandolfi)
Form analysis data for Marginotruncana sigali (Reichel)
Scatter plot of T’X/TX and D-D’ values for M. sigali
(Reichel)
Phylogenetic relationship of Upper Cretaceous Globotruncanidae at the
generic level
Form analysis data for Globotruncana aegyptiaca Nakkady
Scatter plot of T’X/TX and D,-D’,/D,-D’, values for G. aegy pliaca and
G. duwi
Form analysis data for Globoltruncana arca (Cushman)
281
289
291
902
499
294
294
295
296
297
301
302
305
308
308
311
313
313
315
520
$20
399
30. Form analysis data for Globotruncana austinensis Gandolfi 324
31. Scatter plot of D-D’ and T’X/TX values for G. lapparenti Brotzen,
G. bulloides Vogler, and G. austinensis Gandolfi 325
32. Form analysis data for Globotruncana bulloides Vogler 326
33. Form analysis data for G. calcarata Cushman 327
34. Phylogeny of Globotruncana stuarti lineage group 329
35. Suggested phylogenetic relationship of double keeled species of Globo-
truncana S.s. 331
36. Form analysis data for Globotruncana conica White 332
37. Scatter plot of D-D’ and T’X/TX values for G. conica White and G.
stuarti (de Lapparent) 333
38. Form analysis data for Globotruncana contusa (Cushman) 334
39. Scatter plot of D-D’ and T’X/TX values for G. fornicata Plummer and
G. contusa (Cushman) 335
40. Basic types of keel structure among double keeled species of Globo-
truncana s,s. 335
41. Form analysis data for Globotruncana duwi Nakkady 335
42. Form analysis data for Globotruncana elevata (Brotzen) .. Between 338, 339
43. Scatter plot of T’X/TX and D’D values for G. elevata (Brotzen) and
G. stuartiformis Dalbiez 338
44. Variation in chambers shape on spiral side of Globotruncana elevata
(Brotzen) 339
45. Form analysis data for Globotruncana fornicata Plummer 340
46. Form analysis data for Globotruncana gansseri Bolli 342
47. Scatter plot of D-D’ and T’X/TX values for G. gansseri Bolli 342
48. Form analysis data for Globotruncana hilli, n. sp. : 343
49. Form analysis data for Globotruncana lapparenti s.s. Brotzen 345
50. Scatter plot of T’X/TX values and sum of heights of double keels at
D and D’ for G. lapparenti Brotzen and G. linneiana (d’Orbigny) 347
51. Form analysis data for Globotruncana linneiana
(d’Orbigny) Between 348, 349
52. Form analysis data for Globotruncana loeblichi, n. sp. 349
53. Form analysis data for Globotruncana plummerae Gandolf 351
54. Form analysis data for Globotruncana rosetta (Carsey) 352
55. Form analysis data for Globotruncana stephensoni, n. sp. 355
56. Form analysis data for Globotruncana trinidadensis Gandolfi ..... 360
57. Holotype of Globotruncana trinidadensis Gandolfi, X54 360
58. Form analysis data for Globotruncana stuarti (de Lapparent) 361
5°. Form analysis data for
Globotruncana stuartiformis Dalbiez Between 362, 363
60. Form analysis data for Globotruncana ventricosa White a NO
61. Scatter plot of T’X/TX and D,-D’,/D,-D’, values for G. ventricosa *
White and M. concavata (Brotzen) : é e OOS
62. Type locality of Globotruncana ventricosa White. TYPE 4 .... semper. BOS
63. Type locality of peouyes selected for Rosalina canaliculata Reuss. Edel-
bachgraben, Austria. G-19 Sov retts ; estenis renee er
UPPER CRETACEOUS PLANKTONIC
FORAMINIFERA
FROM THE WESTERN GULF COASTAL PLAIN
EMILE A. PESSAGNO, JR.
Southwest Center for Advanced Studies, Dallas, Texas
ABSTRACT
This monograph concerns itself with a study of the Upper Cre-
taceous planktonic Foraminifera of southwestern Arkansas, Texas, and
Mexico. It involves an analysis of the morphology, phylogeny, and
classification of planktonic Foraminifera. A detailed system of zona-
tion utilizing planktonic Foraminifera is presented for the Upper
Cretaceous strata of the western Gulf Coastal Plain area. This system
of zonation is based (1) on the association of important planktonic taxa
at given horizons; (2) the abundance zones and range zones of
planktonic species; and (3) the phylogeny of planktonic Foraminifera
at the specific, generic, and family levels. Biostratigraphic correlation ol
Upper Cretaceous strata cropping out in Arkansas, Texas, and Mexico,
has been presented The majority of the zonal units presented herein
can be recognized throughout the Upper Cretaceous of the Western
Hemisphere and in the Upper Cretaceous of Eurasia and Africa as
well. A detailed paper dealing strictly with the biostratigraphy of the
area of study will be presented elsewhere.
Two new families of Upper Cretaceous planktonic Foraminifera
have been erected: (1) the Marginotruncanidae Pessagno (Turonian
to Santonian) and (2) the Abathomphalidae Pessagno (Campanian to
Maestrichtian). Both of these new families are morphologically distinct
and have great significance in the phylogeny of the planktonic Fora-
minifera.
The Marginotruncanidae Pessagno, n. fam. are characterized (1) by
extraumbilical-umbilical apertures and (2) by large portici (not
tegilla) with infralaminal accessory apertures. This family includes
Whiteinella Pessagno, n. gen. and Marginotruncana Hofker (emended
herein). Whiteinella lacks a keel whereas Marginotruncana Hofker
may be either single- or double-keeled. There seems little doubt
that the Marginotruncanidae represent an intermediate group form-
ing an important phylogenetic link between the Rotaliporidae Sigal
and the Globotruncanidae Brotzen.
The Abathomphalidae are characterized (1) by extraumbilical-
umbilical apertures and (2) by true tegilla ain infralaminal (noi
intralaminal insofar as known) accessory apertures. This family in-
cludes Abathomphalus Bolli, Loeblich, and Tappan and Globotrun-
canella Reiss (emended herein). Abathomphalus possesses a weakly
developed double keel whereas Globotruncanella is keel-less, sometimes
possessing an imperforate peripheral band. The Abathomphalidae
evolved either from the Globotruncanidae or the Rotaliporidae and
may well have given rise to the Globorotalidae Cushman of the early
‘Tertiary.
Two new species have been erected among the Planomalinidae:
Globigerinelloides bollii Pessagno and Globigerinelloides prairiehillensis
Pessagno. One new genus, Loeblichella Pessagno and one new species
Praeglobotruncana bronnimanni Pessagno have been erected under the
Rotaliporidae. One new genus Whiteinella Pessagno has been erected
under the Marginotruncanidae Pessagno, n. fam. ‘Three new species:
Whiteinella archaeocretacea Pessagno, Marginotruncana bouldinensis
Pessagno, and Marginotruncana pseudolinneiana Pessagno have been
erected under the Marginotruncanidae. At the generic level, one new
genus, Archaeoglobigerina Pessagno, has been added under the
Globotruncanidae. The latter family includes the following new
species: Archaeoglobigerina blowit Pessagno, Archaeoglobigerina bos-
quensis Pessagno, Rugoglobigerina tradinghousensis Pessagno, Globo-
truncana hilli Pessagno, Globotruncana loeblichi Pessagno, and Glo-
botruncana stephensoni Pessagno.
A neotype is erected for Rosalina canaliculata Reuss, 1854. Where
necessary, lectotypes have been established for species described by
workers in syntypic series.
Hundreds of planktonic specimens were thin-sectioned both for
form analysis studies and phylogenetic studies. Means and standard
deviations were calculated for many of the form analysis measurements.
Such studies have greatly enhanced the definition of many taxa and
have given the writer a clearer insight into their phylogenetic rela-
tionships.
INTRODUCTION
The planktonic Foraminifera rank with the ammon-
oides, graptolites, and other pelagic groups of invertebrates
as ideal index fossils. Their rapid evolution during Meso-
zoic and Cenozoic times, their cosmopolitan nature, and
their great abundance in many marine sedimentary strata
make them superb biostratigraphic tools for precise world-
wide correlation.
Although the importance of Foraminifera, particularly
in economic paleontology and stratigraphy was recognized
in the 1920’s and 1930’s by Cushman, White, and other
American workers, the planktonic Foraminifera were sadly
neglected in the United States until the advent of the classi-
cal work of Bolli, Loeblich, and Tappan (1957). The Eu-
ropeans, however, were impressed by the biostratigraphic
potential of the planktonic Foraminifera at a much earlier
date. The work of Bolli (1945, 1951), Subbotina (1953),
Bronnimann (1952a, b), Reichel (1950), Mornod (1950) ,
Sigal (1952), Dalbiez (1955), and that of other European
workers did much to foster an interest in planktonic For-
aminifera among American workers.
The last comprehensive survey of Upper Cretaceous
Foraminifera from the Gulf Coastal Plain area was made
by Cushman (1946). Although some planktonic Foramini-
fera were described and figured by Cushman, his mono-
graphic study largely devoted itself to the benthonic
Foraminifera. In addition, changes in the taxonomy of
planktonic Foraminifera have been so great within the last
19 years that most of Cushman’s data are now obsolete and
are rendered useless to those studying the Upper Cretaceous
stratigraphy of the coastal plains.
The present monographic study concerns itself pri-
marily with an analysis of the Upper Cretaceous planktonic
Foraminifera from the western Gulf Coastal Plain area.
Over 600 Upper Cretaceous samples were collected from
the coastal plain of Mexico, Texas, and southwestern
Arkansas (Text-fig. 1). Where possible samples were col-
lected from measured sections or from well cores of Upper
Cretaceous lithic units.
The principal objectives of this monograph are two
fold: (1) to study the external and internal morphology
of Upper Cretaceous planktonic Foraminifera and thereby
bring about a better definition of taxa and (2) to determine
the phylogenetic relationship of the Upper Cretaceous taxa
studied.
Nearly all of the important species encountered in
this study have been illustrated in the 54 plates included
herein. Plates 48-92 contain halftone drawings of unsec-
tioned specimens whereas Plates 93-101 contain photomicro-
graphs of sectioned free specimens,
TEXT - FIGURE 1
PALAEBONTOGRAPHIGA AMERICANA
Index Map. Distribution of UK deposits in Arkansas, Texas, and eastern Mexico.
ane pa Re ae OKLAHOMA = Hug | xo
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=}! &
pa “aN nN
7 Z C. Victoria
f pie
oe yy \ SS .
er Sf ae
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r Son Luis
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KEY:
em = Upper Cretaceous strata.
Modified
Stose,
from the America’,
1946
Vext-figure I.
Geol. Soc. America;
“Geologic
Map of North
PHIN-SEC TIONING PLANKTONIC FORAMINIFERA
In the preparation of this monographic work the in-
vestigator has made numerous thin-sections of oriented free
specimens utilizing the thin-sectioning technique (transpar-
(1958)
by Pessagno (1960b). The application of this technique to
ent slide method) described by Morkhoven and
the study of Upper Cretaceous planktonic Foraminifera
has yielded a wealth of important data concerning their
phylogeny and wall structure. In addition, it has greatly
fascilitated the identification of Upper Cretaceous plank-
tonic Foraminifera in rock thin-sections and the delimita-
tion of taxa at the species level.
(V, 37)
Any study made of Upper Cretaceous planktonic For-
aminifera based on external characteristics alone is hazard-
ous. For example, as will be borne out in this monograph,
homeomorphy or near homeomorphy is common among
many species of Upper Cretaceous planktonic Foraminifera
at least when they are studied on the basis of their external
morphology alone. Two examples can be cited to illustrate
this point. Within the Globotruncanidae, Globotruncana
acgyptiaca Nakkady s.s. can be similar to Globotruncana
rosetta (Carsey) . Sometimes only an experienced worker can
differentiate between these species on the basis of their
external morphology alone. However, when specimens of
these species are thin-sectioned, the differences are marked,
Globotruncana rosetta shows a double-keeled nepionic stage
whereas G. aegyptiaca shows a single-keeled nepionic stage
and develops a double keel only in its late ontogenetic de-
velopment. In another instance, the writer has found that
Globotruncana stephensoni Pessagno, n. sp. can often be a
perfect homeomorph externally for either Globotruncana
conica White or Globotruncana stuarti (de Lapparent) 5.5.
G. stephensoni either has a narrow double keel which
merges to form a single keel early in the last whorl or lacks
a double keel completely in the last whorl. Furthermore, it
may possess trapezoidal or subtrapezoidal chambers on its
spiral side and a spiroconvex test in peripheral view. In
thin-section, however, the differences are again marked. G.
stephensoni, n. sp. shows a double keel early in its onto-
genetic development whereas G. conica and G. stuarti show
a single keel throughout all but the embryonic stage of their
ontogenetic development.
FORM ANALYSIS OF UPPER CRETACEOUS PLANKTONIC
FORAMINIFERA
Planktonic Foraminifera and, indeed, all smaller Fora-
minifera haye been described mostly on a subjective basis.
(1964, pp. 217-230) effective
method of analyzing the form of Recent species of Glo-
Pessagno introduced an
borotalia s.s. from oriented thin-sections. This method is
applicable to the study of a number of smaller Foraminifera
with trochoidal tests providing they display carinate, pseu-
docarinate, or angled peripheries.
Although the method of form analysis cited below and
by Pessagno (1964, bid.) ,is not meant to supplant sound
subjective descriptions of smaller Foraminifera, it does sup-
plement these descriptions with a great deal of data which
are useful in delimiting taxa at the species level.
No attempt has been made to analyze the form of sec-
tioned specimens from horizontal sections although this
might in some instances be useful. It has been found that a
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 25]
much larger number of numerical measurements can be
made from vertical (axial) sections of oriented free speci-
mens. These measurements can be made directly from the
sectioned specimens using a petrographic microscope
equipped with a mechanical stage and an ocular having a
crosshair-type micrometer. The microscope should be prop-
erly centered for the measurement of the anterior and pos-
terior keel angles.
Anterior
lez Plane of
section
Uu
Posterior
TEXT-FIGURE A: Schematic diagram showing line formed
by the intersection of the plane section with the spiral sur-
face of the test.
‘Text-figure A illustrates the line formed by the inter-
section of the plane of section with the spiral surface of the
test. Most of the axial sections made in this study were made
in this plane of section or as close to it as possible.
Text-figure B illustrates diagramatically the type of
measurements that can be made from an axial section of a
carinate, pseudocarinate, or acutely angled trochispiral
planktonic Foraminifera. It should be noted that with
double keeled forms or with forms with an imperforate peri-
pheral band line B-B’ is constructed so that it cuts the
center of the groove between the spiral and umbilical rims
of the double keel structure or so that it bisects the middle
of the imperforate peripheral band. The designations used
in Text-figure B are explained as follows:
Anterior. The end of the test where the final chamber is
located.
Posterior. The portion of the test diametrically opposite the
final chamber.
: D/ B' .
Posterior & <— 8 anterior
TEXT-FIGURE B
B-B’. A straight line drawn through the axis of coiling
(normal to line T-T’) between the anterior and posterior
carinae, pseudocarinae, or peripheral angles.
D-D’. The diameter of the test measured along line B-B’.
C-C’. A line drawn (in the plane defined by B-B’ and the
axis of coiling) across the umbilicus and tangential to the
base or ventral surface of the chambers flanking the umbili-
cus.
U-U’. The distance across the umbilicus measured along
line G-C7.
T-T’. A line drawn along the axis of coiling at right angles
to D-D’ through the approximate center of the earliest
whorl, intersecting the dorsal or spiral surface of the test
at point ‘T and line C-C’ at point T’. This is a measure of
thickness but not necessarily a measure of the maximum
thickness of the test.
X. The point of intersection of line B-B’ with line T-T’.
TX. The distance between point X and point T (the ap-
proximate center of the spiral surface of the test) .
T’X. The distance from point X to point T’.
Angle XDT. The angle formed by lines DT and DX at
the posterior.
Angle XDU. The angle formed by lines DX and DU at the
posterior.
Angle XD’T. The angle formed by lines D’T and D’X at
the anterior.
Angle XD’U’. The angle formed by lines D’X and D’U’ at
the anterior.
This method has proven itself to be useful in delimit-
ing taxa at the species level in the present study. In addi-
tion it has been helpful in solving complex taxonomic
problems centering around planktonic species with sec-
tioned specimens for types.
252 PALAKONTOGRAPHIGA AMERICANA (V, 37)
Some of the more significant data assembled from this
form analysis study have been plotted on scatter diagrams.
Where the data are abundant enough for a given species,
the means and standard deviations of the above measure-
ments have been calculated using an IBM 7040 computer.
(Table 2).
NATURE OF BIOSTRATIGRAPHIC UNITS USED HEREIN
A more detailed report dealing strictly with the Upper
Cretaceous stratigraphy of the western Gulf Coastal Plain
Region will be published elsewhere. A brief summary of the
system of zonation employed and the regional correlation
of strata is shown in Text-figures 2-5. This system of zon-
ation has been modified to a certain degree from that of
Bolli (1957) and Pessagno (1960, 1962) .
In this report the term assemblage zone and its sub-
divisions, swbzone and zonule are used in the sense that
they are used in the “Code of Stratigraphic Nomenclature”
(1961, pp. 655-657). The planktonic foram component of
each assemblage zone or its subdivisions is shown in Text-
figures 3-5. This system of zonation is based on (1) the
association of certain taxa at particular stratigraphic hori-
zons; (2) the relative abundance of taxa at particular strati-
graphic horizons; (3) the range zones and concurrent range
zones of the various taxa; and (4) the phylogeny and evo-
lution of Upper Cretaceous planktonic Foraminifera. Al-
though the planktonic foram component of each assemblage
zone, subzone, or zonule is shown in Text-figures 3-5, these
same Text-figures also indicate the range zones and abund-
ance zones of the taxa under study.
CLASSIFICATION
The classification of planktonic Foraminifera has
evolved a great deal in the last decade. In 1957, Bolli, et al.,
(pp. 19, 20) reviewed all classifications dealing with plank-
tonic Foraminifera published previous to this date and in-
troduced their own well-known classification. The criteria
which Bolli, et al., considered the basis of their classification
at the family, subfamily, generic, and specific level are
shown in Table 1. Since 1957, other workers have presented
classifications which deal solely or in part with planktonic
Foraminifera. Sigal (1958, pp. 862-865) presented a classi-
fication which differed radically from that of Bolli, et al.,
particularly in terms of the criteria he used. For example,
1Recent work now completed by the writer on the primary wall struc-
ture of the Globigerinacea using phase contrast, dark field illumination,
and the electron microscope indicates that true radial hyaline (pris-
matic) wall structure only exists among certain Cenozoic Globigerinacea.
Cretaceous Globigerinacea have primary outer walls that are micro-
granular hyaline in character. Spines, beads, and other ornamental
features are ultragranular hyaline in character as stated in this mono-
graph. These findings do little more than confirm those made 11 years
ago by Bronnimann and Brown (1956, pp. 504-506) on Cretaceous
Globigerinacea.
TABLE 1: CRITERIA FOR CLASSIFICATION
]
aK: | Bolli, et. al Bonner and Blow Pessogno-This work
Units 1957, pp. 20-21 1959, p.2
Wall composition and structure; Modification of primary aperture Structural modification of primary
opertural position; type of (presence of tegilla, portici, aperture. Structural choracter of
> chamber arrangement (type of etc.) modifying structures themselves.
= coiling, etc.) Position of primary aperture.
< Type of chamber arrangement (eg
type of coiling)
il
Modifications of apertures Modifications of primary oper- Presence or absence of accessory
5 Modifications in chamber arrange tures themselves, their shape apertures, relict apertures, sutural
= ment (changes in type of coiling) ond position supplementary apertures, etc.
x Position of primary aperture.
oa
2
a
Position, shape, and character Presence or absence of supple- Presence or absence of keels
of aperture in the adult; presence mentary apertures, relict aper- imperforate peripheral Rent,
or absence of chamber modifica tures together with the develop- pseudocarinae
J tions and general form and ment of elongate, clavate or Structure of keels
Be development of test tubulospinose chambers, and the | Shape of chambers (e.g., clavate)
a presence or absence of imper- Presence of unique sorts of orna-
forote peripheral keels. mentation (rugosities arranged
in meridorial pattern)
Size, relative proportions of Not Stated Relative proportions of test
test, chambers, and apertures, (using a system of form analysis
etc where possible)
Oo Surface ornamentation Surface ornamentation
re Shape of primary aperture
9g Character of early growth stages
a
a
1See also footnote below.
at the family level Sigal stressed such features as the shape
of the adult chambers of the test, the type of coiling, and
the presence of keels, but did not emphasize the position of
the primary aperture. The writer believes that all of Sigal’s
criteria except for the type of coiling should be used to de-
fine taxa below family in rank. Banner and Blow (1959,
pp. 1, 2), although agreeing with Bolli, et al., to some ex-
tent, established a new classification which at the family
level was based primarily on structural modifications of the
primary aperture rather than on the position of the primary
aperture. Furthermore, Banner and Blow (ibid., p. 1) in-
dicated that they disagree with Bolli, et al., over the funda-
mental basis of their classification—the position of the
primary aperture. They stated that Bolli, et al., “— appear to
overemphasize the importance of the precise position of the
interiomarginal aperture relative to the extent of the um-
bilicus and attach little value to the presence or absence of
a keel. As a result, it is often difficult for these authors to
distinguish satisfactorily between superficially similar but
actually unrelated genera. The generic diagnoses given by
them for Praeglobotruncana, and for Globorotalia are vir-
tually indistinguishable, even though the genera are clearly
different and have quite distinct stratigraphical ranges.”
The bases for classification used by Banner and Blow at
the family, subfamily, and generic level are shown in Table
1. Banner and Blow’s classification seems to rely too strongly
on the structural modifications of the primary aperture at
TEXT - FIGURE 2: Upper Cretaceous Correlation Chart. Western Gulf Coastal Plain and Caribbean Areas,
EUROPEAN
STAGE
NAMES
MAESTRICHTIAN
SANTONIAN
TURONIAN
SYSTEM OF ZONATION
NORTH
AMERICAN
STAGE NAMES
(STANDARD
EAGLEFORDIAN
LOZIERIAN* | BOCIAN" |SYCAMORIA
Rotoliporo a8.
SECTION)
NAVARROAN
AUSTINIAN
WASHITIAN
ASSEMBLAGE
ZONES
Globotruncana
contuso — stuartiformis
Assemblage Zone
Globotruncana
fornicata — stuartiformis
Assemblage Zone
Glabotruncana bullotdes
Assemblage Zone
Morginotrur
cono
renzi
Assemblage
Zone
Morginotruncano helvetico
Assemblage Zone
Assemblage Zone
Hedbergello
woshitoensis
Assemblage Zone
ZONULES TAMPICO - SIERRA
MADRE ORIENTAL.
COMPOSITE
SECTION
subpennyi
Globotruncona
Jo)
Globotruncana
colcorata
Pseudotextulario
elegons
Abothompholus
moyoroensis
Globotruncono
gonsseri
Rugotruncona
subcircum-
nodifer
Globotruncona
elevato
Archoeoglob-
igerino
blowi
Globotruncana
fomicoto
Morginotruncana
concovata
Whiteinello
archoeocret-
oceo
Y
Morginotruncono
sigoli
El Abro Lms.
Rotolipora
cushmoni-
greenhornensis
Rotolipora
evoluta
CIUDAD
VICTORIA —
PEREGRINA
CANYON
Aguo Nueva Fm
?
Cuesta del Crura
Tomoulipos Lms.
?
MONTERREY —
BOCA
CANYON
Planoglobulino
glabrata
Dictyomitro
moieties isorele
Son Felipe Fm.
Aguo Nueva Fm.
MAMAULIQUE
PASS (RT 85)
NORTHWARD TO
RANCHO SANTA
CELIA& LA
SPARANZA K1174
Popagollos Shale
?
Popogallos
Shale
Son Felipe Fm
|
Son Felipe Fm
CHISPA
SUMMIT —
VAN HORN
TEXAS
Chispa
Summit
Fm
RIO GRANDE
AREA
LOZIER CANYON
DEL RIO
EAGLE PASS
WHITE CLIFFS
AUSTIN
Escondido Fm.
Corsicana Morl
Lower Toylor
‘Big House’
5| Be quillos
Fm
Austin Chalk
Eagle Ford
Gp
Eagle Ford
Gr
=
3
Engle Ford
G
Eas Lms. | Bedatns. | Ls
[Kane ey [tarp ter —_|
Corsicana Marl
WACO
NAVARRO
CORSICANA
Lower Toylor Lower Toylor
Bruceville
Atco (type)
Austin Cholk
Austin Chall
Arcadia
Pork
Fm
Eagle Ford
pales
'} Eogle Ford
Gp
Pepper Shale
SOUTHWEST
ARKANSAS
TRINIDAD
AFTER
BOLLI 1957.
LOEBLICH &
TAPPAN 1961
Arkadelphia Marl
Guoyoguoyare Fm
Nacotoch Sond_
Soratoge Chalk
Morlbrook Morl
Noparimo
Hill Fm
Goutier Fm
PUERTO RICO
AFTER PESSAGNO.
1961, 1962, 1963
Porguero Lms
Cariblonco Fm.
KEY:
not exposed or
not sampled
hiatus
~—s~
unconformity
*
new substoge
nome
Robles Fm
top ot base
of sampled section
AAA
not found in contact
with each other
+
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Rio Loco Fm. Rio Loco Fm.
uncertain limit
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FORAMINIFERA
ZONULES
calcarata
Pseudotextularia
elegons
Planoglobulina
glabrata
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multicostata
Rugotruncono
subpenny
Globotruncana
lapporentis_s
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moyaroensis
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gonsseri
Rugotruncana
subcircum=
nodifer
igerina
blow:
fornicata
Rotalipora
evoluta
SUBZONES
Archaeoblog=
Globotruncona
cushmoni=
greenhornensis
Abathomphalus
Globotruncana
Morginotruncana
concavata
Whiteinello
archoeocret-
Morginotruncana
GULP CREPACEOL
Izuas
ons
Common
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Hedberge |i
important ond distinctive species
Range Zones and Relative Abundance of Upper Cretaceous
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256 PALAEONTOGRAPHICA AMERICANA (V, 37)
the family level. In the writer’s opinion, it is unwise to
base the definition of a taxonomic unit as large as a family
on a single morphological criterion.
In 1964, Loeblich and Tappan presented a new classi-
fication of planktonic Foraminifera in the Treatise on In-
vertebrate Paleontology (Pt. C, vol. 2, pp. C652-C678) .
Their classification seems to have incorporated some of the
better points of that of Banner and Blow (1959) into the
previous classification presented by Bolli, et al., 1957. How-
ever, new knowledge concerning the morphology of Upper
Cretaceous planktonic Foraminifera makes some parts of
their classification obsolete. Hence, revisions of their classt-
fication have been made herein where necessary. ‘The classi-
fication used by the writer differs only in degree from that
presented by Loeblich and Tappan (1964). The bases for
the classification presented in this monograph at the family,
subfamily, generic, and specific level are shown in ‘Table 1.
SYSTEMATIC PALEONTOLOGY
Phylum PROTOZOA
Subphylum SARCODINA
Class RHIZOPODEA
Subclass GRANULORETICULOSIA
Order FORAMINIFERIDA
Superfamily GLOBIGERINACEA
Remarks. — The definition of the Globigerinacea given
by Loeblich and Tappan (1964, p. C652) is emended herein
to include the findings of Pessagno (1964, pp. 219-220).
Pessagno (/bid.) noted that the septal walls of Globoro-
talia s.s., Globotruncana s.s., and indeed that of all plank-
tonic Foraminifera are microgranular hyaline in character
and are pierced by small, widely scattered pores. Recent
work with the electron microscope appears to confirm the
microgranular nature of the septal walls of most of the
Globigerinacea. However, it remains to be proven whether
individual calcite crystals comprising the septal wall are
oriented at random or with their C-axes normal to the
surface of the septal wall. Although the irregular size and
shape of the crystals suggests a random orientation, their
precise orientation can only be confirmed by X-ray or
electron diffraction. Optical techniques such as those used
by Wood (1963, pp. 156, 157) for Ammonia beccari
(Linné) are futile in that individual crystals are much too
minute to isolate optically.
Spines and ornamental features among the Globiger-
inacea are ultragranular hyaline in character consisting of
one or more large crystals of calcite (Pessagno, loc. cit.) .
Such ornamental structures appear to be superimposed on
the radial hyaline outer portion of the test (of Plate 101, |
figs. 8, 9). (See footnote 1, p. 252).
These findings are quite pertinent to the study of the—
phylogeny of the Rotaliinae at the superfamily level. For
example, Cifelli (1962, p. 125) demonstrated that 4. beccari—
(Linné) has microgranular hyaline septal walls. (Lately the—
writer observed pores in the septal walls of this species.)
Microgranular hyaline septal walls are also present among
other genera of the Rotaliacea, among the Discorbacea,
and among the Buliminacea. In fact, it is probable that
all septate Rotaliinae having radial hyaline outer walls’
likewise have microgranular hyaline septal walls. The
presence of microgranular hyaline septal walls among super-
families of Rotaliinae with radial hyaline outer walls is
clear indication of a close kinship between these super-
families. Furthermore, it is probably indicative of the fact
that Rotaltinae with radial hyaline outer walls evolved
from Rotaliinae with predominantly granular hyaline
outer and septal walls.
The origin of the Globigerinacea seems to be obscure at
the present time largely because the wall structure of other
superfamilies of Rotaliinae is still poorly known in spite of
the work of such workers as Reiss (1957, 1963). In theory,
the origin of the Globigerinacea must be sought among
Rotaliinae which possess bilamellar tests having radial hya-
line outer walls and microgranular hyaline septal walls.
The presence or absence of septal pores in this hypothetical
stock of Rotaliinae may or may not be important.
Among the superfamilies of the Rotaliinae the Glo-
bigerinacea seem most closely allied in terms of their wall
structure and composition to the Rotaliacea. Both super-
families, for example, possess (1) bilamellar test walls that
may be canaliculate; (2) radial hyaline outer walls; and
(5) microgranular hyaline septal walls. Difficulties arise,
however, when one examines the stratigraphic ranges of
the Globigerinacea and Rotaliacea. ‘The Globigerinacea,
according to Loeblich and ‘Tappan (1964, p. C605) have a
range of Jurassic, Lower Cretaceous to Recent whereas
the Rotaliacea have a stratigraphic range of Upper Cre-
taceous to Recent. This geologic distribution certainly does
not suggest that the Globigerinacea evolved from the
Rotaliacea. In fact, it more than likely suggests the reverse.
Perhaps future studies will find that the Rotaliacea are
longer ranging than the present data indicate and_ that
they occur in rocks of Jtirassic or ‘Triassic age.
The Discorbacea are noncanaliculate, monolamellar
Rotaliinae with radial hyaline outer walls and microgranu-
lar septal walls. Their geologic range is Triassic to Recent.
If one ignores their monolamellar and noncanaliculate wall
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
structure, the Discorbacea might be a possible ancestral
stock from which the Globigerinacea could evolve. The
Buliminacea, likewise, have radial hyaline outer walls,
microgranular septal walls, and a geologic range of Triassic
to Recent. The wall structure of the Buliminacea is still
uncertain. Loeblich and ‘Tappan (1964, p. C543), for ex-
ample, failed to state whether the Buliminacea are mono-
lamellar or bilamellar in nature. Reiss (1963, p. 51), in his
definition of the Buliminidea
that these Foraminifera are primarily single layered, but
(= Buliminacea), stated
some genera may be double layered and possess a tectinous
inner lining. Reiss’s definition of the Buliminacea, however,
differs somewhat that of Loeblich and ‘Tappan
(loc. cit.)
In summary, it is difficult to ascertain whether the Glo-
from
bigerinacea evolved from the Rotaliacea, Discorbacea, or the
Buliminacea. At present, the writer feels that differences
in wall structure (.e. monolamellar vs. bilamellar) should
be minimized in terms of their phylogenetic importance
with the Foraminifera. If this is done, it seems more than
likely that the Globigerinacea could have evolved from the
Buliminacea or the Discorbacea. In fact, it is entirely possi-
ble that the Globigerinacea as defined herein and by
Loeblich and Tappan (loc. cit.) are polyphyletic and
evolved in part from both the Discorbacea and the Buli-
minacea. The Heterohelicidae, for example, show strong re-
semblance in chamber arrangement to that of the Buli-
minacea. Trochospiral families such as the Rotaliporidae
on the other hand may have evolved from a Discorbacea
stock.
The evolution of Upper Cretaceous Globigerinacea at
the family level is summarized in ‘Text-figure 6. As inferred
from this text figure, the majority of Upper Cretaceous
families evolved either directly or indirectly from a rotali-
porid stock. The Marginotruncanidae (new family) , as will
be borne out in later discussions and descriptions, occupy
an intermediate position in terms of their morphological
characteristics between the Rotaliporidae s.s. and the Glo-
botruncanidae and hence, serve as a connecting link be-
tween these two families. The Abathomphalidae (new fam-
ily) also appear to be an important link in the phylogenetic
picture. Though they are nearly homeomorphic after the
Globotruncanidae s.s., they may have evolved either from
the Rotaliporidae or the Globotruncanidae. For reasons, to
be discussed later, the writer favors their evolution from the
Globotruncanidae. It is probable that the Abathomphalidae
gave rise to important ‘Tertiary and Quaternary families
such as the Globorotalidae and the Globigerinidae.
The writer once believed that the Rotaliporidae (par-
ticularly the Hedbergellinae) were derived from the Pla-
no
Or
~I
2 2 2 Text — Figure 6: Phylogenetic Relationship of Upper Cretaceous
Spey |e Globiger a the Family Level.
5
ou? =
E 3 ?
z z
= 3
bee eae Re > 5
= of
: a Ez Rc i
=) 5 I =
= 3S B
= ¢ 3
E > o =
= 3
(w) = 2 -
7)
2
= =
= 5
J 5 =
3 c 3
o = c
e = =
s = 8
2 = = 5
S) 5 5 -
= 5 < c
o 7 o
a 3 e S
= : 5 =
= ‘S = =
3
S E
= 5
= 5 5
5 E = a
c S pe
2 3
FE 2
a
ima)
o
wi
: Wood-
5 binian
5
U =
hal =
5
c
c =
5
6
=<
Luwer Cretaceous
Rrederfeesbtraran
als
+= Extinction
Note: Sweliings in life line indicate time
{ greater cbuadance and speciation
nomalinidae. However, Loeblich and ‘Tappan (1964, p.
C656 and p. C659) indicated that the Rotaliporidae (Hed-
bergellinae) first appear in older Hautervian strata whereas
the Planomalinidae first appear in younger Aptian strata.
Hence, it now seems more than likely that the Rotaliporidae
gave rise to the Planomalinidae through a low-spired Hed-
bergellinae stock. The shift in the primary aperture from
an extraumbilical-umbilical position to an equatorial posi-
tion and in coiling from low trochispiral to planispiral
certainly would not be a radical one (Hedbergella to Globi-
gerinelloides). A second interesting possibility should be
explored. It is known that Heterohelix sometimes may have
a planispirally coiled early stage. If the proper mutations
occurred, Heterohelix could have given rise to Globigerinel-
loides and hence, the Heterohelicidae to the Planomalini-
dae. The Schackoinidae appear to have evolved either from
the Planomalinidae or from the Rotaliporidae. As indicated
258 PALAEONTOGRAPHICA AMERICANA (V, 37)
in ‘Text-figure 6, the writer favors their evolution from the
Planomalinidae.
The origin of the Heterohelicidae remains a problem.
As already suggested, the Globigerinacea may be polyphy-
letic at the family level. It is not inconceivable that the
Heterohelicidae evolved directly from some family among
the Buliminacea whereas the Rotaliporidae evolved from
some family among the Discorbacea. The similarity in test
forms among the Heterohelicidae and those among various
families of Buliminacea make this a tempting possibility,
Family HETEROHELICIDAE
Type genus.—Heterohelix Ehrenberg, 1844.
Remarks.—The diagnosis of Loeblich and ‘Tappan
(1964, p. C652) is accepted herein.
Range.—Middle Jurassic to Oligocene.
Occurrence.—World-wide.
Subfamily GUEMBELITRIINAE
Type genus.—Guembelitria Cushman, 1933.
Remarks.—Yhe diagnosis of Loeblich and “Tappan
(1964, p. C652) is followed herein.
Range.—Middle Jurassic to Eocene.
Genus GUEMBELITRIA Cushman, 1933
Type species—Guembelitria cretacea Cushman, 1933.
Range.—Lower Cretaceous—Eocene.
Guembelitria cretacea Cushman
Plate 87, figures 1-3
1933. Guembelitria cretacea Cushman, Contr. Cushman Lab. Foram,
Res., vol. 9, p. 37 pl. 4, figs. 12a, 12b.
1946. Guembelitria cretacea Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 103, pl. 44, figs I4a-c.
1957. Guembelitria cretacea Cushman, Gallitelli, U.S. Nat. Mus., Bull.
No. 215, p. 136, pl. 31, figs la-c.
1960. Guembelitria cretacea Cushman, Olsson, Jour. Paleont., vol. 34,
No. 1, pp. 27, 28, pl. 4, fig. 8.
1964. Guembelitria cretacea Cushman, Loeblich and Tappan, Treatise
on Invert. Paleont., pt. C, Protista 2, vol. 2., p. C652, fig. 523:
la, b.
1964. Guembelitria cretacea Cushman, Said and Sabry, Micropaleont.,
vol. 10, No. 3, p. 390, pl. 3, fig. 32.
Remarks.—This species is characterized by its spherical
chambers, depressed sutures, and highly arched aperture.
Range.—Globotruncana contusa—stuartiformis assem-
blage zone: Globotruncana gansseri subzone.
Occurrence.—In Texas Guembelitria cretacea has been
encountered at numerous localities in the Corsicana marl of
Travis and Limestone Counties and at a few localities in
the Escondido formation of Maverick County. In S.W. Ar
kansas it occurs in the Arkadelphia marl. Cushman (1946,
p- 12 and p. 103) noted its presence in the Kemp clay of
Texas, the Praire Bluff chalk of Mississippi and Alabama,
the upper portion of the Selma chalk of Mississippi, and
in the Ripley formation of Mississippi. According to Cush-
man (bid.) it also occurs in sedimentary deposits of Navar-
roan age from the Georges Bank Canyons and in the Upper
Cretaceous of Colombia. In New Jersey Olsson (1960, pp:
27, 28) noted that G. cretacea is common in the Redbank
formation and in the lower part of the New Egypt forma-
tion. It likewise has been noted by Said and Sabry from the
Maestrichtian of Egypt.
Guembelitria harrisi Tappan
Plate 48, figures 12, 13
1940. Guembelitria harrisi Yappan, Jour. Paleont., vol. 14, No. 2, p.
115, pl. 19, figs. 2a-b.
Remarks.—G. harrisi ‘Tappan differs from G. cretacea
Cushman by having less inflated chambers and a_ low,
slightly arched aperture. Its test often tends to be some-
what more elongate than that of G. cretacea. G. cretacea
“var.” alvertensis Stelck and Wall (1954, p. 23) and G.
cretacea “var.” spritensis Stelck and Wall (1955, p. 44) may
be junior synonyms of G. harrisi Tappan.
Range.—In this study G. harrisi has been encountered
in strata of Cenomanian age (Rotalipora assemblage zone)
and of Albian age (H. washitensis assemblage zone). More
data will be necessary to establish its precise stratigraphic
range.
Occurrence.—G. harrisi has been found in the Grayson
formation (—Del Rio clay) and in the Eagle Ford group
(Britton formation and Lake Waco formation). Loeblich
(1946, p. 132) noted it in the Pepper shale.
Subfamily HETEROHELICINAE
Type genus.—Heterohelix Ehrenberg, 1844.
Remarks.—The phylogeny of the Heterohelicinae is
complex and still not completely understood particularly at
the species level. However, it would appear at the generic
level that Heterohelix gave rise to Gublerina, Psewdoguem-
belina, Pseudotextularia, and Planoglobulina during the
time interval from ‘Turonian to Late Maestrichtian (Text-
figure 7) .
Range.—Lower Cretaceous to Oligocene.
Occurrence.—World-wide.
Genus HETEROHELIX Ehrenberg, 1843
Type species.—Spiroplecta americana Ehrenberg, 1844
Remarks.—Yhe diagnosis of Loeblich and Tappan
(1964, pp. C652-C654) is followed herein.
It should be noted that the first striate or costate species
of Heterohelix, H. reussi (Cushman), made its appearance
in the M. helvetica assemblage zone. No striate Heterohelix
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 259
| All [ Salle
Sou
Slee Seco 4 Text — Figure 7; Phylogenetic Relationships ot Upper Cretaceous
=o
call Bz Ones Heterohelicinae at the Generic Level.
Ema Zzeoa
w <
5
re |
8
=
So
a
c
c o €
‘J = =
= 5 of cy v e
= 2 c = 2 =
) rs = = E >
= o © x o -)
a = + 2 a <
> ao;
° a
3 z 8 = a 3
3 c
= 2 3 Z 5
a
3 Oo a me
u
= c S
2 = x
= =
Ss x
°
E Ey e
Be : :
= 2
c : | ro)
S 5 |
a = ry
3 2 = ?
é = \
© 6 c
o a 5 I
BL || E
° = Sl
c o cS
ve S = 3)
oO 3 < 21
a 3 2
a = a
= 5 ol
1) S|
r
Beh |
s | = |
2 5
& 2
a CS am
3
Ww
Wood-
binion
Cenomunian
Washitian
Lower Cretaceous
Fredricksburgian
H* First Striate Heterohelix
+= Extinction Note: Swellings in life lines indiccte times 91 greater abundance and
speciation
have been observed in the Rotalipora assemblage zone.
Abundant striate Heterohelicinae are particularly charac-
teristic of Upper Campanian and Maestrichtian strata in
the Gulf Coast and Caribbean Regions. Costae are ultra-
granular hyaline imperforate structures superimposed on
the radial hyaline outer wall of the test. Costae always occur
in the interpore areas of species whose pores have been
aligned in rows.
Heterohelix glabrans (Cushman)
Plate 88, figures 1, 2, 10, 11
1938. Guembelina glabrans Cushman, Contr. Cushman Lab. Foram.
Res., vol. 14, p. 15, pl. 3, figs. 1, 2.
1946. Guembelina glabrans Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 109, pl. 46, figs. 17a-b, 18.
1960. Heterohelix glabrans (Cushman), Olsson, Jour. Paleont., vol. 34,
No. 1, pp: 26, 27, pl. 4, fig. 4.
Remarks.—Heterohelix glabrans (Cushman) is similar
to Heterohelix pulchra (Brotzen) but differs from the
latter species by having a finely perforate, smooth, polished,
compressed test and by having an aperture that is two or
three times higher than it is broad. The general arrange-
ment of the chambers does, however, suggest a close phylo-
genetic relationship between H. glabrans and H. pulchra. It
is likely that H. glabrans evolved from H. pulchra during
Early Maestrichtian times (R. subpennyi zonule) .
Range.—G. contusa—G. stuartiformis assemblage zone:
G. ganasseri subzone to A. mayaroensis subzone. The holo-
type (Cushman Coll., USNM) of this species has been ex-
amined and compared to specimens encountered during this
study.
Occurrence.—Heterohelix glabrans has been observed
by the writer at the type locality of the Méndez shale (Mén-
dez Station, MX 206; see Appendix) in Mexico, in the
Corsicana marl and Kemp clay of Texas, and in the
Arkadelphia marl of Arkansas. Cushman (1946, p. 109)
noted that it occurs in the Prairie Bluff chalk of Alabama
and in the upper part of the Selma chalk of Tennessee. Ac-
cording to Olsson (1960, pp. 26, 27) this species has been
reported in New Jersey from the Navesink formation and ts
known to occur rarely in the Redbank and New Egypt for-
mations.
Heterohelix globocarinata (Cushman)
Plate 86, figures 5, 6
1938. Guembelina globocarina'a Cushman, Contr. Cushman Lab.
Foram. Res., vol. 14, p. 10, pl. 2, figs. 4-5.
1946. Guembelina globocarinata Cushman, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, pp. 107, 108, pl. 46, figs. 8a-b, 9.
Remarks.—Vhis species is characterized by its inflated
final chambers, by its carinate periphery in the early por-
tion of the test, by its large, lowly arched aperture, and by
the finely striate nature of its test. H. globocarinata seems
to be closely related to both H. globulosa (Ehrenberg) and
to H. striata (Ehrenberg). The holotype (Cushman Col-
lection, USNM examined and figured herein) shows a
planispirally coiled initial stage. The two paratype slides in
the Cushman Collection (USNM) contain specimens which
are not entirely assignable to this species. For example, one
slide (Cushman Coll. 24373) contains a single specimen of
Pseudotextularia elegans (Rzehak) 5.s. The other (Cush-
man Coll. 31642) contains H. globulosa (Ehrenberg) , H.
globocarinata, and Pseudotextularia elegans (Rzehak) s.s.
Range.—The precise range of this species is uncertain
because of its rareness in Upper Cretaceous strata. Its type
locality according to Cushman (1946, p. 107) occurs in the
Taylor formation (“Upper Taylor marl” member) .
Occurrence.—Cushman (1946, p. 108) noted that H.
260 PALAEONTOGRAPHICA AMERICANA (V, 37)
globocarinata at a number of localities of Navarroan, ‘Tay-
lorian, and Austinian age. However, the comprehensive
nature of the present study seems to refute not only such
an extensive biostratigraphic range, but also such a wide
geographic occurrence. It is likely that most of Cushman’s
data are incorrect and probably represent misidentifications
of this species on his part.
Heterohelix globulosa (Ehrenberg)
Plate 87, figures 5-9, 11-13
1840 (1838). Textularia globulosa Ehrenberg, K. Preuss. Akad. Wiss.
Berlin, Abh., p. 135, pl. 4, figs. 2 beta, 4 beta, 5 beta, 7 beta, 8
beta.
1899. Guembelina globulosa (Ehrenberg), Egger, K. Bayer. Akad. Wiss.
Math.—naturh. Abt. Abh. KI. 2, vol. 21, pt. 1, p. 32, fig. 43.
1931. Guembelina spinifera Cushman, Tennessee Diy. Geol., Bull. 41,
p. 43, pl. 7, figs. 8a-b.
1946. Guembelina spinifera Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 108, pl. 46, figs. 15a-b.
1946. Guembelina globulosa (Ehrenberg), Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, pp. 105, 106, pl. 45, figs. 9-15.
1951. Guembelina globulosa (Ehrenberg), Loeblich, Contr. Cushman
Found. Foram. Res., vol. 2, pt. 3, p. 108, pl. 12, figs. 4, 5.
1957. Heterohelix globulosa (Ehrenberg), Gallitelli, U.S. Nat. Mus.,
Bull., No. 215, p. 137, pl. 31, figs. 12-15.
Remarks.—Ehrenberg (1840, pl. 4) figured Textularia
globulosa in syntypic series from the following widely sep-
arated geographic localities and different stratigraphic
horizons: (1) Jutland, Denmark (=fig. 2 beta); (2)
(=heg. 4 beta); (3) Meudon near
Paris, France (=fig. 5 beta); (4) ‘“Mokattamgebirge” near
Cairo, Egypt (=fig. 7 beta); (5) Thebes in Upper Egypt
from the Nuwmmulites limestone of the Pyramids (=fig. 8
beta). Ellis and Messina (Catalogue of Foraminifera) note
that the type specimens of T. globulosa Ehrenberg are de-
posited in the Akademie Wissenschaften, Berlin.
Gravesand, England
Figure 5 beta and the corresponding specimen in the
Ehrenberg collection are designated herein as the lecto-
type figure and the lectotype respectively of 7.
Ehrenberg. The Meudon chalk at Meudon near Paris
seems to be the most likely unit from which this specimen
originated. Meudon (Maulineaux Hill) and the Meudon
chalk, therefore, are designated the type locality and type
lithic unit of T.
Gignoux (1955, p. 418, fig. 112) the Meudon chalk contains
Belemnitella mucronata. The remaining figures except for
figure 8 beta are designated paralectotypes. It seems unwise
to designate figure 8 beta as a paralectotype in that the
globulosa
globulosa (Ehrenberg). According to
specimen figured is from the Nummutlites limestone of
Tertiary age and may represent Chiloguembelina rather
than Heterohelix.
The selection of figure 5 beta as the lectotype of T.
globulosa is in keeping with the modern concept of the
species as expressed by Cushman (1946, p. 106) and Loeb-
lich (1951, p. 103). This figure is the most compatible of
all Ehrenberg’s figures with the modern concept of the
species. Furthermore, the selection of the Meudon chalk at
Meudon as the type lithic unit is likewise compatible with
Stratigraphic data associated with the modern concept of
the species. If Ehrenberg’s types no longer exist as a result
of the great destruction in Berlin during World War II, it
is suggested that a neotype be selected from the Meudon
chalk as exposed at Maulineaux Hill, Meudon, France.
It should be noted that both Cushman and Loeblich
failed to note the presence of faint costae on all but the last
several chambers of the test. H. globulosa (Ehrenberg)
seems to be similar to H. reussi (Cushman). However, H.
reusst shows well-developed fine costae on all chambers of
its test, less inflated chambers, and prominent triangular
areas between the last several chambers of the test. It is
likely that H. globulosa evolved from H. reussi as suggested
by Cushman (ibid.)
The holotype of H. spinifera (Cushman) , deposited in
the Cushman Collection (USNM), was examined and found
to fall within the limits of H. globulosa (Ehrenberg) . Cush-
man (1946, p. 108) noted that this species is distinct from
H. globulosa because it has short spines scattered over the
whole surface of its test. The holotype, however, lacks these
spines. Cushman’s (1931 and 1946) figures are misleading.
Range.—G. fornicata—stuartiformis assemblage zone, A.
blow? subzone to G. contusa—stuartiformis assemblage zone,
A. mayaroensis subzone. Bronnimann and Brown (1953, p-
150) noted H. globulosa in the Upper Maestrichtian of
Cuba in a faunal assemblage containing A. mayaroensis
(Boll) .
Occurrence.—In the present study H. globulosa has
been encountered in strata of Taylorian and Navarroan
age throughout Arkansas, Texas, and Mexico. It occurs in
the following units in this region: Méndez shale, Upson
clay, San Miguel formation, Escondido formation, “Lower
Taylor marl,” Wolfe City sand, Pecan Gap chalk, “Upper
Taylor marl”, Neylandville marl, Corsicana marl, Kemp
clay, Brownstown marl, Ozan formation, and Marlbrook
marl.
Heterohelix moremani (Cushman)
Plate 48, figs. 10, 11; Plate 89, figs. 1, 2
1938. Guembelina moremani Cushman, Contr. Cushman Lab. Foram.
Res., vol. 14, p. 10, pl. 2, figs. 1-3.
1940. Guembelina washitensis Tappan, Jour. Paleont., vol. 14, No. 2,
p- LIS) pl los figs:
1946. Guembelina moremani Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, pp. 103, 104, pl. 44, figs. 15, 16; not fig. 17.
1962. Heterohelix sp. Ayala, Soc. Geol. Mexicana, Bol., vol. 25, No. 1
p. 11, pl. 1, figs. la-c; pl. 6, figs. la-c.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 261
Remarks.—The writer has examined the holotype and
paratypes of H. moremani in the Cushman Collection
(USNM). The holotype is refigured herein. This specimen
is abnormally large for the species. All of the paratypes and
the majority of the specimens assignable to this species en-
countered in this study are much smaller. One of Cush-
man’s paratypes (cf. Cushman, 1946, pl. 44, fig. 17) is not
Heterohelix moremani but is referable to Planoglobulina
sp. It is important to point out that this represents the
oldest documented occurrence of Planoglobulina as far as
the writer is aware.
Larger specimens and gerontic specimens of H. more-
mani, such as the holotype, tend to show a more highly
arched aperture whereas smaller specimens, such as that
figured on Plate 48 (figures 10, 11), show lowly arched
apertures. The aperture seems to become more highly
arched during ontogeny.
Heterohelix moremani has a smooth, finely perforate
test which lacks striae and pores aligned in rows. It is likely
that Heterohelix reussi evolved from a Heterohelix more-
mani stock during Early ‘Turonian times.
Tappan (1940, p. 115) separated H. washitensis from
H. moremani largely on the basis of the former’s smaller
size and more lowly arched aperture. The holotype of H.
(Cushman Collection, USNM)
was examined during this study and found to be similar to
washitensis (Cushman)
the smaller, less mature forms of H. moremani occurring in
the Eagle Ford group. The investigator has likewise ex-
amined numerous topotypic specimens from the Grayson
formation, near Roanoke, Texas. The differences between
H. washitensis and H. moremani seem too slight to warrant
their clear cut separation. Therefore, in this paper H. washi-
tensis is treated as a junior synonym of H. moremani.
Range.—Albian — (?) ;
Turonian: Rotalipora s.s. assemblage zone to M. helvetica
Lower Cenomanian — Upper
assemblage zone.
Occurrence.—H. moremani has been observed in the
San Felipe formation of Mexico. In Texas, it occurs in the
Grayson formation (Del Rio clay) and throughout the
Eagle Ford group (Britton formation, Arcadia Park forma-
tion, Lake Waco formation, and South Bosque formation)
of ‘Texas. It is conceivable that specimens of H. moremani
occurring in the Turonian portion of the Eagle Ford group
have been reworked from Cenomanian Eagle Ford strata.
As noted in Text-figure 2, Lower Turonian strata (M.
sigali subzone) are missing throughout ‘Texas (except at
Chispa Summit) at least in surface outcrop.
Heterohelix navarroensis Loeblich
Plate 89, figures 8, 9
1951. Heterohelix navarroensis Loeblich, Contr. Cushman Found.
Foram. Res., vol. 2, pt. 3, pp. 107, 108, pl. 12, figs. 1-3b, text
ager, Lh
1957. Heterohelix navarroensis Loeblich, Gallitelli, U.S. Nat. Mus.,
Bull., No. 215, p. 137, pl. 31, figs. 5a-11.
1960. Heterohelix navarroensis Loeblich, Olsson, Jour. Paleont., vol.
34, No. 1, p. 26, pl. 4, fig. 5.
1962. Not Heterohelix navarroensis Loeblich, Pessagno, Micropaleont.,
vol. 8, No. 3, p. 358, pl. 1, fig. 4.
Remarks.—Heterohelix navarroensis Loeblich is some-
what similar to Heterohelix striata (Ehrenberg) . It differs
from H. striata largely in the more laterally compressed and
finely costate character of its test and in its smaller size. In
addition, whereas H. navarroensis commonly displays a
planispirally coiled initial stage H. striata only rarely dis-
plays such a planispiral initial stage.
The form figured by Pessagno (1962, pl. 1, fig. 4) was
reexamined and found to be assignable to H. striata.
The holotype of H. navarroensis was examined in the
Cushman Collection (USNM).
Range.—G. fornicata—stuartiformis assemblage zone, R.
subcircumnodifer subzone to G. contusa—stuartiformis as-
semblage zone, G. gansseri subzone.
Occurrence.—In this study H. navarroensis has been ob-
served in the Corsicana marl, the Kemp clay, the San Miguel
formation, and the Escondido formation of Texas, and in
the Marlbrook marl and Arkadelphia marl of Arkansas. It
has not been found to date in the Méndez shale.
Olsson (1960, p. 27) noted H. navarroensis in the
Navesink, Redbank, and New Egypt formations of New
Jersey.
The present data appear to indicate that H. navar-
roensis is primarily a Boreal species.
Heterohelix planata (Cushman)
Plate 86, figures 3, 4; Plate 89, figures 6, 7
1938. Guembelina planata Cushman, Contr. Cushman Lab. Foram.
Res:, vol. 14, p. 12) fig. 13, 14.
1946. Guembelina planata Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 105, pl. 45, figs. 6a-b, 7.
1960. Hieterohelix pulchra (Brotzen), Olsson, Jour. Paleont., vol. 34,
No. 1, p: 27, pl. 4, fig. 6.
Remarks.—Heterohelix planata (Cushman) is some-
what similar to H. pulchra (Brotzen) but differs from the
latter species by possessing chambers which are not so
broad or reniform in side view and by being more costate.
Accessory apertures were observed on some specimens (cf.
1 AA Hen RF
Jub, CE eS Os 7). bs
The specimen figured by Olsson (1960, p. 27, pl. 4, fig.
6) as H. pulchra (Brotzen) appears to be H. planata (Cush-
man) . Its final chambers are not reniform and the surface of
the test is covered by fine costae.
262 PALAEONTOGRAPHICA AMERICANA (V, 57)
The holotype of H. planata (Cushman) (Cushman
Collection, USNM) has been examined and reillustrated in
this report.
Range.—G. fornicata—stuartiformis assemblage zone, G.
elevata subzone to G. contusa—stuartiformis assemblage
zone, G. gansseri subzone.
Occurrence.—In the present study H. planata has been
observed in the “Upper Taylor marl” and in the Corsicana
marl of Texas. Cushman (1946, p. 105) also noted its pres-
ence in the Pecan Gap chalk. It has not been observed in
strata of equivalent age in Mexico.
Heterohelix pulchra (Brotzen)
Plate 87, fig. 4
1936. Guembelina pulchra Brotzen, Sver. Geol. Unders. Avh., Ser. C,
No. 396, p. 121, pl. 9, figs. 3a-b; not figs 2a-2b.
1938. Guembelina pseudotessera Cushman, Contr.
Foram. Res., vol. 14, p. 14, pl. 2, figs. 19-21.
1946. Guembelina pseudotessera Cushman, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, pp. 106, 107, pl. 45, fig. 16-20.
1957. Heterohelix pulchra (Brotzen) , Gallitelli, U.S. Nat. Mus., Bull.,
No. 215, p. 137, pl. 31, fig. 20.
1960. Not Heterohelix pulchra (Brotzen), Olsson, Jour. Paleont., vol.
SE INO} ps2; Plat, igs 6:
1962. Heterohelix pulchra (Brotzen), Pessagno, Micropaleont., vol.
8, No. 3, p. 358, pl. 1, fig. 3.
Cushman Lab.
Remarks.—TYhe broadened or reniform nature of its
last two or three chambers makes this species distinct from
similar species like H. planata and H. glabrans. ‘The writer
has observed faint costae on Early Maestrichtian specimens
from Puerto Rico.
The form figured by Brotzen (1936, pl. 9, figs. 2a-b) is
not H. pulchra and in fact, is assignable to Planoglobulina
sp.
Range.—In this study and in work in Puerto Rico the
writer has found this species to be restricted to the G.
fornicata—stuartiformis assemblage zone. Occurrences by
Cushman (1946, p. 107) in the upper portion of the Austin
chalk cannot be regarded at present as being in the under-
lying G. bulloides assemblage zone. The upper portion of
the Austin chalk, particularly in northeastern ‘Texas, was
reworked extensively during Early Campanian or Early
Taylorian times (Text-figure 2) .
Occurrence.—In the Gulf Coast Region the investigator
has observed this species in the Méndez shale of Mexico and
in the Upson clay and Upper ‘Taylor marl of ‘Texas. In
Puerto Rico H. pulchra (Brotzen) has been observed in
the Parguera limestone, the Cariblanco formation, and in
the Rio Yauco formation. Cushman (1946, p. 107) noted
H. pulchra in the Upper
Taylor marl, Pecan Gap chalk, and Lower Taylor marl
members of the Taylor formation (Texas); in the lower
(= pseudotessera Cushman)
and middle parts of the Selma chalk (Mississippi) ; in the
Annona chalk (Texas) ; in the Brownstown marl (Texas) ;
and in the upper part of the Austin chalk (Texas) .
Heterohelix punctulata (Cushman)
Plate 86, figs. 7-10
1938. Guembelina punctulata Cushman, Contr. Cushman Lab. Foram.
Res;, vol: 14,"p. 13; pl: 2, figs: 15) 16:
1946. Guembelina punctulata Cushman, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 108, pl. 46, figs. 14a-b.
1953. Pseudoguembelina punctulata (Cushman), Bronnimann and
Brown, Contr, Cushman Found. Foram. Res., vol. 4, pt. 4, p. 154,
text-figs. 7, 8.
1962. Heterohelix punctulata | (Cushman), Pessagno, Micropaleont.,
VOSS NOs 3sips.o28,) pla lar tigs lille
Remarks.—Heterohelix punctulata is characterized by
its coarsely punctate or cancellate surface, by its large size,
and by the fact that it is nearly 1.5 times as long as it is
broad. ‘The last four to five pairs of chambers usually are
large compared to the earlier chambers. The punctate sur-
face of the test is due to the presence of heavy, massive rims
surrounding each pore and pore pit. Many specimens such
as the holotype (Cushman Collection, USNM) figured
herein contain accessory apertures. Weak costae appear to
be present in the interpore areas of the earlier chambers.
This species was placed in Pseudoguembelina by Bronn-
imann and Brown (1953, p. 154) due to its frequent pos-
session of sutural supplementary apertures. Gallitelli (1957,
pp. 139, 140) stated that sutural supplementary apertures
may On rare occasion be present among species of Hetero-
helix. However, the present study indicates that they are in
fact common among species of Heterohelix. Sutural supple-
mentary (accessory) apertures have definitely been observed
among specimens of H. striata (Ehrenberg), H. planata
(Cushman) , H. pulchra (Brotzen), H. moremani (Cush-
man), and H. reussi. H. punctulata lacks the elongate,
somewhat (accessory) flaps present
among species of Pseudoguembelina s.s. such as P. costulata
(Cushman) and P. excolata (Cushman) .
Range.—G._ fornicata—stuartiformis assemblage zone,
tubular apertural
A, blow: subzone (D. multicostata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence.—In_ this study H. punctulata has been
observed in the San Felipe formation and Méndez shale of
Mexico; in the “Lower Taylor marl,” “Upper Taylor marl,”
Neylandville marl, and Corsicana marl] of Texas; and in the
Brownstown marl of Arkansas. In Puerto Rico it has been
found in the Parguera limestone, the Rio Yauco formation,
and the Rio Blanco formation. Bronnimann and Brown
(1953, p. 150) noted that H. punctulata occurred with a
Late Maestrichtian assemblage of planktonic Foraminifera
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 263
in Cuba (A. mayaroensis subzone) . This appears to be the
youngest occurrence of H, punctulata in the Cretaceous of
the Western Hemisphere. The above range zone is based in
part on the data of Bronnimann and Brown.
Cushman (1946, p. 108) noted H. punctulata in the
Wolfe City sand and in the Annona chalk of ‘Texas.
Heterohelix reussi (Cushman)
Plate 85, figures 1-9; Plate 86, figures 1, 2
1938. Guembelina reussi Cushman, Contr. Cushman Lab. Foram. Res.,
VOlmI4 a pals ple 2s atlose 10-955
1946. Guembelina reussi Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 104. pl. 44, figs. 18a-b, 19.
1956. Not Guembelina reussi Cushman, Said and Kenawy, Micro-
paleont., vol. 2, No. 2, p. 139, pl. 3, fig. 32.
Remarks.—As already noted, Heterohelix reussi: (Cush-
man) is similar to Heterohelix globulosa (Ehrenberg) . It
also is somewhat similar to Heterohelix striata (Ehrenberg) .
H. reussi differs from H. globulosa by the more costate and
compressed nature of its chambers and by the fact that its
later chambers are distinctly set apart by large depressed tri-
angular areas. This species differs from H. striata in the
possession of the aforementioned characteristics and in the
possession of somewhat finer costae.
Cushman stated that the surface of H. reussi is smooth
and finely perforate. However, the holotype and paratypes
of H. reussi (Cushman Collection, USNM) from the Austin
chalk, though poorly preserved, definitely show the presence
of fine costae. The investigator has found costae to be pres-
ent on H. reussi wherever it has been observed in Upper
Cretaceous strata except in places where preservation was
poor.
The specimen figured by Said and Kenawy (1956, pl. 3,
fig. 32) is not H. reussi, but Pseudotextularia sp.
H. reussi may represent the basic stock from which
most Campanian and Maestrichtian species of Heterohelix
evolved. It is the dominant species of Heterohelix in Upper
Eaglefordian and in Austinian strata.
Range.—M. helvetica assemblage zone, M. sigali sub-
zone to G. fornicata-stuartiformis assemblage zone, A. blowi
subzone.
Occurrence.—During the course of this study H. reussi
was noted in the Turonian, Coniacian, Santonian portions
of the San Felipe formation throughout the area studied in
Mexico. It is likewise known from the lower portion of the
Méndez shale (Text-figure 2) .
In Texas H. reussi was noted in ‘Turonian portion of
the Eagle Ford group in Terrell, Val Verde, Travis, Mc-
Lennan, and Dallas Counties. It is also known from the
Coniacian and Santonian portions of the Austin chalk in
Val Verde, Kinney, Travis, McLennan, and Dallas Counties
and in the Lower Taylor marl of Travis, McLennan, and
Dallas Counties. In southwest Arkansas it occurs in the
Brownstown marl.
Cushman (1946, p. 104) noted H. reussi in the lower
part of the Selma chalk of Mississippi and in the Ozan for-
mation of Arkansas. The writer has never observed this
species in the Ozan.
Heterohelix semicostata (Cushman)
Plate 98, fig. 21
1938. Guembelina semicostata Cushman, Contr. Cushman Lab. Foram.
Res., vol. 14, p. 16, pl. 3, fig. 6.
1946. Guembelina semicostata Cushman, U.S. Geol. Sur., Prof. Paper,
No. 206, p. 107, pl. 46, figs. la-1b, 2 (?), 3, 4(?), 5.
Remarks. — The Collection,
USNM) of H. semicostata was examined and compared to
holotype = (Cushman
the two rare specimens of this species encountered during
the course of this survey. The figured specimen (PI. 98, fig.
21) shows relatively heavy, widely spaced costae which
occur along the side and peripheral margins of the test.
These costae fail to be distinct in the microphotograph be-
cause of their hyaline nature. They are easily observable,
however, in reflected light with a stereoscopic microscope.
H. semicostata seems somewhat related to species of Gub-
lerina. Its septa, though widely spaced, are not so widely
spaced as those of typical specimens of Gublerina. It may
represent a transitional form linking Heterohelix with
Gublerina.
Range.—G. fornicata—stuartiformis assemblage zone
(undifferentiated) .
Occurrence.—In the present study the investigator has
observed H. semicostata in the Méndez shale and in the
“Neylandville” marl. Because this species is so rare, the de-
tails of its precise stratigraphic occurrence are given herein
as well as in a future paper dealing with the biostratigraphy.
In the Méndez shale one specimen of H. semicostata was
found to occur at MX 15 (see Appendix), in the R. sub-
circumnodifer subzone (R. subpenny: zonule). In the “Ney-
landville” marl one specimen of H. semicostata was found
at locality No. 52 of Cushman (1946, p. 3) in a fauna which
is assignable to the G. elevata subzone (G. calcarata zonule) .
Cushman (1946, p. 107) noted H. semicostata in the
Neylandville marl, the “Upper Taylor marl,” and in the
“Lower Taylor marl.” It would seem then that H. semi-
costata has a range zone which extends from near the base
to the top of the G. fornicata—stuartiformis assemblage
zone. Although it is distinctive, it is probably too rare to
be a good guide fossil.
264 PALAEONTOGRAPHICA AMERICANA (V, 37)
Heterohelix striata (Ehrenberg)
Plate 78, figures 4, 5; Plate 88, figures 3-7; Plate 98, figure 16
1840. Textularia striata Ehrenberg, K. Preuss. Akad. Wiss. Berlin,
(1838) Abh., p. 135, pl. 4, figs. 1 alpha, 1 alpha prime, 2 alpha,
3 alpha, (not 9 alpha) .
1899. Guembelina striata (Ehrenberg), Egger, K. Bayer. Akad. Wiss.,
Math.—naturh., Abt., Abh., Kl. 2, vol. 21, p. 33, pl. 14, figs.
37-39; not 5-7, 10, 11.
1946. Guembelina striata (Ehrenberg), Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, pp. 104, 105, pl. 45, figs. 4, 5.
1953. Pseudoguembelina striata (Ehrenberg) , Bronnimann and Brown,
Contr. Cushman Found. Foram. Res., vol. 4, pt. 4, p. 154, text-
fig. 6 (p. 151).
1962. Heterohelix striata (Ehrenberg), Pessagno, Micropaleont., vol.
8, No. 3, p. 358, pl. 1, fig. 5.
1962. Heterohelix navarroensis Loeblich, Pessagno, Micropaleont.,
vol. 8, No. 3, p. 358, pl. 1, fig 4-
1962. Heterohelix striata (Ehrenberg), Berggren, Stockholm Contr.
Geol., vol. 9, No. 1, pp. 21, 22, pl. 6, figs. la-5b.
Remarks.—TYhe taxonomic status of H. striata (Ehren-
berg) is in much the same uncertain state as that of H.
globulosa (Ehrenberg). The type specimens of H. striata
like those of H. globu’osa came from a number of geo-
eraphic localities and stratigraphic horizons. Ehrenberg
(ibid., pl. 4) cited that his figured specimens were collected
from the following localities: (1) “Puszkary’” in Poland
(=figs. 1 alpha and 1 alpha prime); (2) Jutland, Den-
mark (=fig. 2 alpha); (3) “Insel Rugen” in Pommern,
Germany (=fig. 3 alpha). Figure 9 alpha of Ehrenberg is
probably referrable to Pseudotextularia elegans (Rzehak) .
According to Ellis and Messina (Catalogue of Foramini-
fera) the type specimens of 7. striata like those of T.
globulosa are deposited in the Akademie Wissenschaften in
Berlin.
Figure 2 alpha and the corresponding specimen are
formally designated herein as the lectotype figure and the
lectotype specimen of Textularia striata (Ehrenberg) . Fur-
thermore, the type locality of T. striata Ehrenberg is desig-
nated herein as Kjolby Gaard, Jutland, Denmark, and the
Kjolby Gaard marl is designated the type lithic unit (cf.
Berggren, 1962, pl. 5). The specimens figured by Berggren
(ibid. pl. 6 figs. la-5b) from the Kjolby Gaard marl can
be regarded as topotypes of H. striata (Ehrenberg) . If the
specimen corresponding to Ehrenberg’s figure 2 alpha is
missing in the Ehrenberg Collection of the Akademie der
Wissenschaften, Berlin, a neotype should be selected from
the Danish locality cited above. Figures 1 alpha, | alpha
prime, 3 alpha, and their corresponding specimens are desig-
nated paralectotypes.
Heterohelix striata is similar to Heterohelix globulosa
in terms of chamber shape and arrangement. It differs
from H. globulosa by possessing well-developed medium
costae which in ephebic specimens cover all but the last
several chambers of the test. Smaller neanic specimens show
costae on all chambers.
In 1953 Bronnimann and Brown placed this species in
Pseudoguembelina on the basis of the presence of accessory
apertures. As noted previously herein (p. 27) and_ by
Gallitelli (1957, in Loeblich, et al., 1957, p. 139) such
accessory apertures occur among a number of species of
Heterohelix. Pseudoguembelina (cf. Gallitelli, 1957, pp.
139, 140) is differentiated from Heterohelix by its posses-
sion of elongate, tubelike apertural flaps which extend
down from and cover each tiny accessory aperture, Hetero-
helix striata lacks such apertural flaps even when it is well
preserved.
Range.—G._ fornicata—stuartiformis assemblage zone,
A. blowi subzone, D. multicostata zonule to G. contusa—
stuartiformis subzone, A. mayaroensis subzone.
Occurrence.—In this study H. striata (Ehrenberg) has
been observed in the Méndez shale of Mexico; in the “Low-
er Taylor marl,” Pecan Gap chalk, “Upper Taylor marl,”
Neylandville marl, Upson clay, Corsicana marl, and Kemp
clay of Texas; and in the Brownstown marl, Ozan forma-
tion, Saratoga chalk, and Arkalephia marl of Arkansas. 1.
striata has also been observed in the upper-most part of
the Austin chalk [‘“Hutchins” chalk member of Durham
(MS 1957) or Upper chalk of Dallas Geol. Soc.] at Dallas,
Texas. The upper five feet or more of the Austin chalk in
this area were often reworked during Early Taylorian times
and are assignable to the G. fornicata—stuartiformis assem-
blage zone, A. blow? subzone, P. glabrata zonule.
Pessagno (1960, p. 91; 1962, p. 358) noted H. striata
in the Parguera limestone, Cariblanco formation, and Rio
Yauco formation in Puerto Rico. Bronnimann and Brown
(1953, p. 154) noted H. striata in deposits of Late Maes-
trichtian age (A. mayaroensis subzone). Bronnimann and
Rigassi (1963, pp. 201-280) noted numerous occurrences of
this species in the Habana group (Pre-Via Blanca beds, Via
Blanca formation, and Penalver formation) of Cuba.
H. striata is likewise common in the Campanian and
Maestrichtian deposits of Eurasia and Africa.
Heterohelix ultimatumida (White)
1929. Guembelina ultimatumida White, Jour. Paleont., vol. 3, No. 1,
p- 39, pl. 4 figs. 13a-b.
1946. Not Guembelina ultimatumida White, Cushman, U.S. Geol.
Sur., Prof. Paper, No. 206, p. 107, pl. 46, figs. 6a-b, 7.
1962. Heterohelix ultimatumida (White), Pessagno, Micropaleont.,
vol. 8, No. 3, p. 356, pl. +l, fig. 8.
Remarks.—Heterohelix ultimatiumida (White) seems
to be closely related to H. striata (Ehrenberg). It differs
from H. striata by the greatly inflated and enlarged nature
of the last two or three chambers of the test. The test as a
whole is about three quarters as wide as it is long and is
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 265
covered by well-developed medium costae. The aperture is a
low, lunate opening at the base of the last chamber.
Neither of the forms figured by Cushman (1946, pl.
46) appear to be assignable to H. ultimatuwmida. The form
in figure 6 lacks the low, lunate aperture characteristic of
this species. Its aperture is highly arched and narrow. ‘This
form most likely is referable to Pseudoguembelina palpebra
Bronnimann and Brown. Figure 7 of Cushman bares little
or no resemblance to H. ultimatumida.
The type locality of 1. wltimatumida is cited by White
(1929, p. 39; 1928, p. 182) as being “In an arroyo in Chap-
acao, 5.5 kilometers north of Chijol station.” According to
Dr. John Imbrie (personal communication) the type speci-
mens of G. ultimatumida White are missing from the White
Collection at Columbia University. A neotype will have to
be selected by future workers if the type specimen cannot be
located. The writer has examined hypotypes from the type
Méndez shale from near Méndez Station.
Range.—G, fornicata—stuartiformis assemblage zone—
possibly higher.
Occurrence.—Méndez shale, ‘Taylor formation. In
Puerto Rico, the writer observed H. ultimatwmnida in the
Parguera limestone, Rio Yauco formation, and the Cari-
blanco formation.
Genus GUBLERINA Kikoine, 1948
Remarks—The diagnosis presented by Loeblich and
‘Tappan (1964, pp. C054-C655) is followed herein.
Range.—Upper Cretaceous.
Type species.—Gublerina cuvilieri (=Ventilabrella
ornatissima Cushman and Church, 1929) .
Gublerina decoratissima (de Klasz)
1953. Ventilabrella decoratissima de Klasz, Geol. Bavarica, No. 17, p.
228, pl 4, figs. 5a-b.
1957. Gublerina decoratissima (de Klasz), Gallitelli, U.S. Nat. Mus.
Bull; No. 215, p. 140, pl. 32, fig. 8.
Range.—Uncertain. Occurs in the G. bulloides assem-
blage zone, M. concavata subzone.
Occurrence.—Specimens of G. decoratissima were found
at MX 110 (San Felipe formation, Peregrina Canyon; see
Appendix) and at MX 157 (San Felipe formation, Boca
Canyon; see Appendix) . This species has not been observed
at other localities during the course of this study. It was
originally described by De Klasz from the lowermost part
of the Bucheck beds of southeastern Germany from strata
which are of Santonian age.
Gublerina glaessneri Bronnimann and Brown
glaessnert’ Bronnimann and Brown, Contr. Cushman
5
1953. Gublerina
Found. Foram. Res., vol. 4, pt. 4, pp. 155, 156, text-figs. 13a, b;
14a-b.
1957. Gublerina glaessneri Bronnimann and Brown, Gallitelli, U.S.
Nat. Mus., Bull., No. 215, p. 141, pl. 32, fig. 7.
Remarks.—The holotype of G. glaessneri was examined
at the U.S. National Museum during the course of this
study. A specimen of G. glaessneri was found after the plates
for this work were finished. Hence, G. glaessneri is not
illustrated herein.
Range and occurrence.—To date this species has only
been found in the Gulf Coast area at the type locality of
the Méndez shale (Méndez Station, MX 206; see Appendix) .
The fauna at this locality is assignable to the G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone,
Bronnimann and Brown (1953, p. 150) originally described
G. glaessneri from strata of the same age in Cuba.
Gublerina robusta de Klasz, 1953
Plate 75, figure 11
1953. Gublerina acuta subsp. robusta de Klasz, Geol. Bavarica, No. 17,
p- 247, pl. 8, figs. 4a, b; 5a, b.
1953. Gublerina hedbergi Bronnimann and Brown, Contr. Cushman
Found. Foram. Res., vol. 4, pt. 4, p. 155, text-figs. lla, b; 12a, b.
1957. Gublerina acuta robusta de Klasz, Gallitelli, U.S. Nat. Mus., Bull.,
No. 215, p. 141, pl. 32, fig. 9.
Remarks.—A paratype of G. acuta robusta de Klasz and
the holotype of G. hedbergi, deposited at the U.S. National
Museum, were examined during the course of this study.
Range.—G. fornicata—stuartiformis assemblage zone:
G. elevata subzone (G. calcarata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence.—In this study G. robusta has been ob-
served in the Méndez shale of Mexico and in the Corsicana
marl of Texas. Bronnimann and Brown (1953, p. 150)
noted G. robusta in strata assignable to the A. mayaroensis
subzone. Cuban occurrences of G. robusta are also noted
by Bronnimann and Rigassi (1963, p. 250) in the Via
Blanca formation, Habana group.
Genus PSEUDOGUEMBELINA Bronnimann and Brown, 1953
Type species.—Guembelina exco’ata Cushman, 1926.
Remarks.—Pseudoguembelina, as noted by Gallitelli
(1957, p. 139), differs from Heterohelix mainly by the pos-
session of small secondary sutural supplementary apertures
covered by elongate, tubelike apertural flaps. Inasmuch as
Heterohelix commonly shows sutural supplementary aper-
tures, it is only the possession of such distinctive apertural
flaps that separates Psewdoguembelina from Heterohelix.
266 PALAEONTOGRAPHICA AMERICANA (V, 37)
Loeblich and Tappan (1964, p. C656) failed to mention
the possession of these flaps in their description of Pseudo-
guembelina in the Treatise of Invertebrate Paleontology.
Pseudoguembelina evolved from Heterohelix during
Late Campanian or Taylorian times. Pseudoguembelina cos-
tulata (Cushman), the first species of this genus to occur,
made its appearance in strata assignable to the G. elevata
subzone (P. elegans zonule). It is likely that P. costulata
itself arose from a H. striata ancestor. By Middle Maestrich-
tian times (G. gansseri subzone) , P. costulata gave rise to P.
excolata (Cushman) and to P. palpebra Bronnimann and
Brown.
Range.—G. fornicata—stuartiformis assemblage zone. G.
elevata subzone (P. elegans zonule) to G, contusa—stuartt-
formis assemblage zone, A. mayaroensis Subzone.
Occurrence.—Campanian—Maestrichtian North Amer-
ica, West Indies, South America, Eurasia, Africa.
Pseucoguembelina costulata (Cushman)
Plate 79, fig. 1; Plate 88, figs. 8-9; Plate 90, fig. 3
1938. Guembelina costulata Cushman, Contr. Cushman Lab. Foram.
Res., vol. 14, p. 16, pl. 3, figs. 7-9.
1946. Guembelina costulata Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 108, pl. 46, figs. 10a-b, ib Wes
1953. Pseudoguembelina costulata (Cushman), Bronnimann and
Brown, Contr. Cushman Found. Foram. Res., vol. 4, pt. 4, pp.
153, 154, text-tig. 5.
1956. Pseudoguembelina costulata (Cushman), Said and Kenawy,
Micropaleont., vol. 2, No. 2, p. 139, pl. 3, fig. 36.
1957. Pseudoguembelina costulata (Cushman) , Gallitelli, U.S. Nat.
Mus., Bull., No. 215, p. 139, pl. 31, figs 21, 22.
1959. Pseudoguembelina costulata (Cushman), Ayala, Univ. Nacional
Aut. de Mexico, Instit. Geol., Paleont. Mexicana, No. 4, pp. 18,
19, pl. 1,-figs. 1-4.
1960. Pseudoguembelina excolata (Cushman), Olsson, Jour. Paleont.,
vol. 34, No. 1, p. 28, pl. 4, fig. 11.
1962. Pseudoguembelina costulata (Cushman), Pessagno, Micropale-
ont., vol. 8, No. 3, p. 537, pl. 1, fig. 6.
Remarks.—P. costulata differs from P. excolata by its
narrower outline in side view and by possessing fine rather
than massive costae.
The holotype and paratypes of G. costulata Cushman
were examined during the course of this study. Cushman’s
paratype slide (Cushman Coll. No. 31745, USNM) contains
10 specimens. Of these 10 specimens, 9 are referrable to P.
costulata and 1 to Heterohelix striata (Ehrenberg) .
Range.—G. fornicata-stuartiformis assemblage zone, G.
elevata subzone (P. elegans zonule) to G. contusa—stuarti-
formis assemblage zone, A. mayaroensis subzone.
This species makes its first appearance at the base of
the G. elevata subzone. Its first appearance serves as one
criterion for separating the G. elevata subzone from the A.
blowi subzone.
Occurrence.—In the present study P. costulata has been
observed in the Late Campanian and Maestrichtian portions
of the Méndez shale of Mexico. In Texas it occurs in the
“Upper Taylor marl” of Travis and Limestone Counties;
the Neylandville marl of Delta County; the Corsicana marl
of Travis and Navarro Counties: the Kemp clay of Travis
and Falls County; and the Escondido formation of Maver-
ick County. In southwestern Arkansas, P. costulata occurs
in the Ozan formation; the Marlbrook marl; the Saratoga
chalk; and the Arkadelphia marl.
Cushman (1946, p. 108) noted P. costulata in the “Low-
er Taylor marl” and Nacatoch sand of ‘Texas; in the Ripley
formation of Tennessee; and in the Prairie Bluff chalk of
Mississippi and Alabama. It should be noted that Cush-
man’s “Lower Taylor” locality No. 206 is cited by Bolli, et
al. (1957, p. 268 expl. fig. 21) as being an “Upper Taylor”
locality. The writer has never seen this species in the “Low-
er Taylor” although the upper portion of this member of
the Taylor formation may occur in the G. elevata subzone,
P. elegans zonule. In Mexico, P. costulata does occur in the
P. elegans zonule.
Pessagno (1960, p. 91; 1962, pp. 355, 358) noted this
species at numerous localities in the Parguera limestone and
Rio Yauco formation of Puerto Rico. Bronnimann and
Brown (1953, p. 150) noted P. costulata in the A. maya-
roensis subzone of Cuba. Ayala (1959, pp. 4-7) recorded
P. costulata from the Upper Cretaceous of Haiti at locali-
ties C.P. 131, 135, 218, 263, 264, 273, 274. A number of
these localities appear assignable to the G. elevata subzone,
G. calcarata zonule.
P. costulata is also known to occur in strata of Upper
Campanian and Maestrichtian age in South America, Eur-
asia, and Africa.
Pseudoguembelina excolata (Cushman)
Plate 68, figs. 4-5; Plate 90, fig. 5
1926. Guembelina excolata Cushman, Contr. Cushman Lab. Foram.
Res., vol. 2, p. 20, pl. 2, fig. 9.
1926. Textularia costata Carsey, Univ. Texas Bull. 2612, p. 26, pl. 1,
fig. 4.
1927. Guembelina excolata Cushman, Cushman, Jour. Paleont., vol. 1,
p. 157, pl. 28, fig. 13.
1929. Guembelina excolata Cushman, White, Jour. Paleont., vol. 5, No.
lp: 34, plea; figs. /-
1946. Guembelina excolata Cushman, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, pp. 108, 109, pl. 46, figs. 16a-b.
1953. Guembelina excolata (Cushman), Hamilton, Jour. Paleont.,
vol. 27, No. 2, p. 234, pl. 30, fig. 11.
1953. Pseudoguembelina excolata (Cushman), Bronnimann — and
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 267
Brown, Contr. Cushman Found. Foram. Res., vol. 4, pt. 4, p- 153,
text-figs. 1-4. nore
1957. Not Pseudoguembelina excolata (Cushman) , Gallitelli, U.S. Nat.
Mus., Bull., No. 215, p. 139, pl. 23, fig. 23.
1961. Pseudoguembelina excolata (Cushman), Said and Kerdany,
Micropaleont., vol. 7, No. 3, p. 332, pl. 2, fig. 11.
1964. Not Pseudoguembelina excolata (Cushman) , Loeblich and ‘Tap-
pan, Treatise of Invert. Paleont., pt. C, Protista 2, vol. 2 p. C656,
fig. 525: 5, 6.
Remarks.—Pseudoguembelina excolata (Cushman) is
distinguished from Pseudoguembelina costulata (Cushman)
by its coarse costae and by its much broader test in side
view. The holotype (Cushman Collection, USNM), which
was examined during the course of this study, is coarsely
costate and is nearly as broad as it is long. P. excolata differs
from P. palpebra Bronnimann and Brown by its more
broadened or reniform and much less inflated chambers.
Furthermore, whereas P. excolata has nearly flat or gently
arched flaps covering sutural supplementary apertures,
those of P. palpebra are strongly arched and form tubelike
structures.
The specimens figured by Gallitelli (1957, pl. 31, fig.
23) and by Loeblich and Tappan (1964, fig. 525: 5, 6) are
assignable to P. palpebra rather than to P. excolata.
The final chambers of these specimens appear to be in-
flated and to be nearly as tall as wide in side view. Further-
more, one form figured by Loeblich and Tappan (1964,
fig. 525: 6) shows highly arched, tubelike flaps covering its
sutural supplementary apertures.
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert Subzone—A. mayaroensis subzone.
Occurrence.—In the course of this work P. excolata has
been found in the Méndez shale of Mexico and the Corsi-
cana marl and Kemp clay of Texas. Cushman (1946, p.
108) noted P. excolata in the Arkadelphia marl of south-
western Arkansas.
According to Cushman (1946, p. 104) the type locality
of this species is in the east bank of the Tamuin River, 5
kilometers southeast of Guerrero (— Tamuin), San Luis
Potosi, México. This locality in the Méndez shale occurs in
close proximity to and directly along strike with a number
of localities of the writer which are assignable to the 4.
mayaroensis subzone.
In Cuba Bronnimann and Brown (1953, p. 150) noted
P. excolata in strata which contain a fauna assignable to the
A, mayaroensis subzone. Bronnimann and Rigassi (1963,
pp. 223-280) noted P. excolata in the Campanian to Middle
Maestrichtian Via Blanca formation and in the Upper
Maestrichtian Penalver formation of the Habana group.
P. excolata is well known in the Upper Cretaceous
(Maestrichtian) strata of Eurasia and Africa.
Pseudoguembelina palpebra Bronnimann and Brown
Plate 78, figs. 1-3; Plate 89, figs. 3-4
1953. Pseudoguembelina palpebra Bronnimann and Brown, Contr.
Cushman Found. Foram. Res., vol. 4, pt. 4, p. 155, text-figs.
9a-b; 10a-b.
1957. Pseudoguembelina excolata (Cushman), Gallitelli, U.S. Nat.
Mus., Bull., No. 215, p. 139, pl. 23, fig. 23.
1959. Pseudoguembelina cornuta, Seiglie, Assoc. Mex. Geol. Petrol.
Bol., vol. 11, pp. 60, 61, pl. 4, figs. la-b; 2a-b; 3a-b; 4a-b; 5a-b;
6; 7.
1964. Pseudoguembelina excolata (Cushman), Loeblich and Tappan,
Treatise of Invert. Paleont., pt. C, Protista 2, vol. 2 p. C656, fig.
25 osm Os
Remarks.—As previously noted P. palpebra differs from
P. excolata by (1) possessing inflated chambers which are
nearly as wide as high in side view and (2) having sutural
supplementary apertures which are covered by highly
arched, tubelike apertural flaps. Furthermore, the final
chamber of some specimens is laterally compressed (cf.
Bronnimann and Brown, 1953, text-fig. 10). Like P. exco-
lata, P. palpebra possesses coarse to medium costae. The
tubelike character of the apertural flaps is illustrated by
Bronnimann and Brown (1953, text-figs. 9-10) and by Loeb-
lich and Tappan (1964, fig. 525: 6).
The writer can see little if any difference between the
forms illustrated by Bronnimann and Brown (ibid.) as
P. palpebra and the forms illustrated by Seiglie (1959, pl.
4, figs. 1-7) as P. cornuta.
The holotype and paratypes (USNM) of P. palpebra
Bronnimann and Brown were examined during the course
of this study.
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert Ssubzone—A. mayaroensis subzone.
Occurrence.—H. palpebra has been found in the upper
part of the Méndez shale of Mexico; the Corsicana marl
and Kemp clay of Texas; and the Arkadelphia marl of
Arkansas during the course of this study (Text-figure 2) .
Bronnimann and Brown (1953, zbid.) originally de-
scribed this species from the Upper Maestrichtian (A.
mayaroensis subzone) of Cuba.
Genus PSEUDOTEXTULARIA Rzehak, 1891
Type species.—Cuneolina elegans Rzehak, 1891.
Remarks.—The diagnoses presented by Gallitelli (1957,
p. 138) and by Loeblich and Tappan (1964, p. C656) are
followed herein.
Range.—Campanian—Maestrichtian.
Occurrence.—World-wide.
268 PALAEKONTOGRAPHICA AMERICANA (V, 37)
Pseudotextularia elegans (Rzehak)
Plate 75, figs. 12-17; Plate 85, figs. 10, 11; Plate 88, figs. 14-16;
Plate 89, figs. 10-11; Plate 97, fig. 18; Plate 98, figs. 19, 20
1891. Cuneolina elegans Rzehak, Naturhist. Hofmus, Ann., Wien, vol.
6 Novrlp: ot
1895. Pseudotextularia varians Rzehak, Naturhist. Hofmus, Ann.
Wien, vol. 10, pt. 2, p. 217, pl. 7, figs. la-b (lectotype) ; not figs.
235
1929. Guembelina elegans (Rzehak), White, Jour. Paleont., vol. 3, No.
1, pp. 34, 35, pl. 4, fig. 8.
1937. Guembelina plummerae Loetterle, Nebraska Geol. Sur., ser. 2
Non ll2) prssaiple o; figs. 1-2.
1946. Guembelina plummerae Loetterle, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 104, pl. 45, figs. 1-3.
1950. Guembelina plummerae Loetterle, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 221-A, p. 7, pl. 3, figs. 21, 22.
1953. Guembelina plummerae Loetterle, Hamilton, Jour, Paleont., vol.
ZENO 2p Pesoes Plsns0s fig 30:
1956. Bronnimannella plummerae (Loetterle) , Gallitelli, Contr. Cush-
man Found. Foram. Res., vol. 7, pt. 2, p. 35, pl. 7, figs. 1, 2.
1957. Pseudotextularia elegans (Rzehak), Gallitelli, U.S. Nat. Mus.,
Bull., No. 215, p. 138, pl. 33, figs. 6a-c.
1959. Pseudotextularia elongata Seiglie, Assoc. Mex. Géol. Petrol;
Bol., vol. 11, pp. 58, 59, pl. 1, figs. 2a-b; 4a-b; pl. 2, figs. la-b;
2a-b; 4a-b; 6a-b; pl. 3, figs. la-b; text-fig. 4.
1959. Pseudotextularia elegans (Rzehak), Seiglie, Assoc. Mex. Géol.
Petr., Bol., vol. 11, pp. 55, 56, pl. 1, figs. la-b; 3a-b; text-fig. 4.
1960. Not Pseudotextularia elegans (Rzehak), Olsson, Jour. Paleont.,
vol. 34, No. 1, p. 28, pl. 4, figs. 9, 10.
1962. Pseudotextularia elegans (Rzehak), Pessagno, Micropaleont.,
vol. 1, No. 3, p. 356, pl. 1, figs. 7, 9.
1964. Pseudotextularia elegans (Rzehak), Loeblich and ‘Tappan,
Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2, p. C656,
fig. 525: 7a-c.
Remarks.—P. elegans (Rzehak) differs from P. deformis
(Kikoine): (1) by possessing medium costae which are
closer together rather than coarse costae which are widely
separated; (2) by having highly arched rather than plani-
form septal partitions in peripheral section (cf. Pl. 97,
figs. 17, 18); (3) by having thinner test walls; (4) by
having a test which is lobulated in peripheral view; (5)
by having chambers which gradually increase in size periph-
erally and which are sometimes nearly as tall as they are
wide; and (6) by having a lowly arched, nearly slitlike
primary aperture.
The writer has found that there is little significant
difference between the lectotype of P. elegans (Rzehak) (P.
varians Rzehak figs. la-b) and the figured types of P. elon-
gata Seiglie. Hence, P. elongata Seiglie is regarded as a
junior synonym of P. elegans (Rzehak) .
In this paper a narrower form (in peripheral view)
which corresponds to the lectotype of P. elegans is called P.
elegans s.s. The wider, more robust form, figured by Loet-
terle (1937), Cushman (1946), Gallitelli (1956) , and Loeb-
lich, et al., (1957) is referred to herein as P. elegans s.l. Al-
though the differences in form between P. elegans s.s. and
P. elegans s.l. are apparent, numerous gradations exist be-
tween these two extreme end members. In addition P. ele-
gans s.s. and P. elegans s.1. have nearly the same stratigraphic
range. Hence, in this paper these two forms are regarded
as variants of the same species. Future studies of P. elegans
s.s. and s./. should stress the form analysis of sectioned speci-
mens. Measurements from such a form analysis study might
be critical in the separation of these variants.
P. elegans probably evolved from a Heterohelix striata
(Ehrenberg) stock during Early Campanian or Taylorian
times.
Ranege.—G. fornicata—stuartiformis assemblage zone, A.
blowi subzone (D. multicostata zonule) —G. contusa—stuar-
tiformis assemblage zone, G. gansseri subzone; possibly A.
mayaroensis subzone. P. elegans is rare in the G. contusa—
stuartiformis assemblage zone in the Western Hemisphere.
Many of the European references referring to an abundance
of P. elegans in the G. contusa—stuartiformis assemblage
zone should be rechecked. It is likely that P. elegans may
have been confused with P. deformis (Kikoine) by many
workers.
Occurrence.—In the present study P. elegans has been
noted in the Méndez shale of Mexico; the “Lower ‘Taylor
marl,” “Upper Taylor marl,” Upson clay, Neylandville
marl, and Corsicana marl of Texas; and the Brownstown
marl and Arkadelphia marl of Arkansas.
In addition to the units mentioned above, Cushman
(1946, p. 104) noted P. elegans under the name of G. plum-
merae Loetterle in the Austin chalk (undifferentiated) ,
Burditt marl, Wolfe City sand, Pecan Gap chalk, and
Annona chalk of Texas, and in the Selma chalk of Missis-
sippi and Alabama. It is likely that Cushman’s references
to Austinian occurrences of this species in Texas either
represent upper Austin localities showing ‘Taylorian re-
working (cf. Text-fig. 2, Dallas area) or erroneous identi-
fications of P. elegans. The present investigator has never
seen P. elegans in his numerous Coniacian and Santonian
samples from the Austin chalk.
P. elegans is known from the Niobrara chalk of Kansas
and Nebraska (cf. Loetterle, 1937). Cushman (1946, p. 104)
also noted that it occurs subsurface in the Selma chalk of
Florida.
Pessagno (1960, p. 95; 1962, p. 356, pl. 1, figs. 7, 9)
noted P. elegans in the Parguera limestone, Cariblanco
formation, Rjo Yauco formation, and the Rio Blanco forma-
tion of Puerto Rico. Seigle (1959, pp. 55, 56; 58, 59) noted
this species in the Campanian and Maestrichtian of Cuba.
P. ele
gans is well known throughout the Campanian
GULE CRETACEOUS FORAMINIFERA: PESSAGNO 269
and Maestrichtian of South America, Eurasia, African, and
the mid-Pacific guyot area. From its geographic occurrences
P. elegans seems to be both a good Boreal and ‘Tethyan
guide fossil.
Pseudotextularia deformis (Kikoine)
Plate 90, figures 16; Plate 92, figures 19-21; Plate 97, figures
16, 17; Plate 98, figures 15, 17, 18
1926. Pseudotextularia sp. a Plummer, Univ. Texas Bull. 2644, p. 35,
Ple2higenl.
1948. Guembelina striata (Ehrenberg) var. deformis Kikoine, Soc.
Géol. France, Bull., sér. 5, vol. 18, p. 20, pl. 1, figs. 8a-c.
1953. Pseudotextularia elegans Rzehak cf. var. deformis (Kikoine) ,
de Klasz, Geol. Bavarica, No. 17, pp. 232, 233, pl. 5, fig. 3a-b.
1959. Pseudotextularia bronnimanni Seiglie, Assoc. Mex. Geol. Petrol.,
Bol., vol. 12, pp. 57, 58, pl. 1, figs. 5a- 5b; 6a, 6b; 7a, 7b; 8a, 8b:
text-fig. 4.
1960. Pseudotextularia elegans (Rzehak), Olsson, Jour. Paleont., vol.
34, No. 1, p. 28, pl. 4, figs. 9, 10.
Description.—Test biserial, covered by widely spaced,
coarse costae; apical portion sharply pointed and constricted
in well-preserved specimens. Pointed apical portion often
followed closely by sudden expansion of chambers in width.
Chambers, as seen in peripheral view, expanding slowly in
width after the initial expansion at early stage of develop-
ment; last several chambers sometimes not so wide as preced-
Final chamber often offset from biserial
arrangement, occupying a central position. ‘Test outline not
ing chambers.
lobulate in either side or peripheral view; ellipsoidal in
shape in side view. Sutures depressed, straight to gently
arched in peripheral view; depressed, slightly curved in side
view. Peripheral sections of oriented free specimens show-
ing planiform or platform-like septal partitions. Aperture
highly arched opening at base of final chamber. Outer test
wall thick, bilamellar, radial hyaline perforate; septal
partitions microgranular hyaline perforate; costae ultra-
granular hyaline imperforate.
Remarks.—P. deformis (Kikoine) differs from P. ele-
gans (Rzehak) :
spaced costae (cf. Pl. 97, fig. 16); (2) by having nearly
planiform rather than highly arched septal partitions when
seen in peripheral section (cf. Plate 97, figs. 17, 18; Pl. 98,
figs. 15, 20); (3) by having thicker test walls; (4) by having
a test which is usually not so highly lobulated in peripheral
(1) by possessing coarser, more widely
view and which often assumes an ellipsoidal shape in side
view; (5) by having chambers in peripheral view which
increase more rapidly in width at an earlier stage of develop-
ment and which are about 1/2 as tall as they are wide;
and (6) by having a more highly arched primary aperture.
Smaller or well-preserved tests of P. deformis from the
Kemp clay frequently show a pointed, fragile apical portion.
This is usually broken off in less well-preserved material or
on tests of ephebic or gerontic individuals. P. bronnimanni
Seighe (1959) is considered a junior synonym of P. defor-
mis (Kikoine) .
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert to A. mayaroensis subzone. This species is an im-
portant guide fossil in strata of Middle to Late Maestrich-
tian age throughout the Western Hemisphere. It is dis-
tinctive and abundant in strata of this age.
Occurrence.—In the present study P. deformis has been
found in the Méndez shale and Papagallos shale of Mexico;
the Corsicana marl and the Kemp clay of Texas; and the
Arkadelphia marl of Arkansas. Seiglie (1959, p. 57) re-
corded this form from Cuba under the name of P. bronni-
manni in strata containing faunal assemblages assignable to
the G. gansseri subzone and the A. mayaroensis subzone. In
the Tampico area of Mexico the writer observed P. de-
formis in Méndez shale strata containing A. mayaroensis
(Bolli), G. stwarti (de Lapparent) s.s., G. conica White,
Racemiguembelina fructicosa (Egger) and other species
diagnostic of the A. mayaroensis subzone. In Trinidad the
writer has observed P. deformis in samples given to him by
H. Bolli from the same stratigraphic horizon in the
Guayaguayare formation. It is also known from the Mae-
strichtian of Bavaria and France.
Pseudotextularia intermedia de Klasz
Plate 86, fig. 11
1953. Pseudotextularia intermedia de Klasz, Geol. Bavarica, No. 17,
p- 231, pl. 5, figs. 2a-2c.
Remarks.—Pseudotextularia intermedia de Klasz_ is
closely related to Pseudotextularia elegans (Rzehak). It
differs only from the latter species in that it shows the
formation of several small chambers which tend to crown
the biserial test and lie outside of the usual biserial arrange-
ment of the earlier chambers. Seiglie (1959, p. 53) believed
that P. intermedia represents an intermediate species be-
tween P. elegans (Rzehak) and Racemiguembelina fruc-
ticosa (Egger). However, the writer feels certain that R.
fructicosa is derived from a P. deformis (Kikoine) ancestor.
Range.—Uncertain. Probably G. fornicata—stuartifor-
mis assemblage zone, R. swhcircumnodifer subzone to G.
contusa—stuartiformis assemblage zone, A. mayaroensis sub-
zone.
Occurrence.—In this study P. intermedia has been found
only at a single locality (MX 78, see Appendix) in the
Méndez shale. Here it is associated with dAbathompalus
270 PALAEONTOGRAPHICA AMERICANA (V, 37)
mayaroensis (Bolli), Globotruncana stuarti (de Lappar-
ent) s.s., G. conica (White) as well as a few elements which
seem to suggest reworking of Méndez strata assignable to
the G. fornicata—stuartiformis assemblage zone.
De Klasz (1953, p. 231) originally described P. inter-
media from the Maestrichtian of Upper Bavaria in south-
eastern Germany. He noted that it occurs in beds above the
“Globotruncana calcarata Zone”.
Genus RACEMIGUEMBELINA Gallitelli, 1957
Type species —Guembelina fructicosa Egger, 1900
Remarks.—The diagnoses of Gallitelli (1957, p. 142)
and of Loeblich and Tappan (1964, p. C656) are followed
herein.
Seiglie (1959, pp. 52-54) included Racemiguembelina
in Pseudotextularia in his redefinition of the latter genus.
Furthermore, Seiglie maintained that P. elongata Seiglie
(= a junior synonym of P. elegans (Rzehak) , P. echevarriai
Seiglie, and P. intermedia de Klasz occasionally show rare
additional chambers suggestive of a multiserial arrange-
ment.
The present investigator feels that such transitional
forms are expectable in nature and simply support the thesis
that Racemiguembelina evolved from a Pseudotextularia
stock (Text-figure 7). Racemiguembelina, as defined by
Gallitelli (¢bid.) and by Loeblich and ‘Vappan (ibid.) is
morphologically distinct from Pseudotextularia as defined
by the same authors. Furthermore, its radically different
stratigraphic range argues for its existence as a distinct
taxon.
Range.—G. contusa—stuartiformis assemblage zone;
Upper portion of G. gansseri subzone to A. mayaroensis
subzone.
Occurrence.—Maestrichtian of North America, West
Indies, South America, Eurasia, and Africa. Boreal and
Tethyan faunal provinces.
Racemiguembelina fructicosa (Egger)
Plate 90, figs. 14, 15
1895. Pseudotextularia varians Rzehak, Naturh., Hofmus, Ann., Wien,
Ostereich, vol. 10, pt. 2, p. 217, pl. 7, figs. 2, 3 (mot figs. la, b).
1900 (1899) Guembelina fructicosa Egger, K. Bayer. Akad. Wiss.
Munchen, Math.-Phys. Cl., Bd. 21 (1902), Abt. 1 (1899), p. 35,
pl. 14, figs. 8, 9; 24 (not figs. 25, 26).
1929. Pseudotextularia varians Rzehak, White, Jour. Paleont., vol. 5,
No. 1, p. 40, pl. 4, figs. 15a, b.
1929. Pseudotextularia varians var. mendezensis White, Jour. Paleont.
vol. 3, No. 1, p. 41, pl. 4, figs. 16a, b.
1936. Pseudotextularia elegans (Rzehak) var. varians Rzehak, Glaess-
ner, Probl. Pal., Moscow Univ. Lab. Pal., vol. 1, p. 101, pl. 1, figs.
3-5, text fig. lc. (Fide Berggren, 1962) .
1946. Pseudotextularia varians Rzehak, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 110, pl. 47, figs. 4a, b; 6; 7a, b; 9a, b (not
5a) bs 8a: b)i-
1950. Pseudotextularia varians Rzehak, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 221-A, p. 8, pl. 3, fig. 26.
1955. Pseudotextularia elegans (Rzehak), Bettenstaedt and Wicher
(part), Fourth World Petrol. Congr., Proc., sect. I/D, Paper 5,
p. 510, fig. 6 (left). (Fide Berggren, 1962) .
1956. Pseudotextularia elegans (Rzehak), Hofker, Palaent., Zeit., Bd.
30, p. 77, fig. 78. (Fide Berggren, 1962) .
1957. Pseudotextularia varians (elegans) Rzehak, Hofker (part),
Beih. Geol. Jahrb., H. 27, p. 424, text-figs. a-h; j-m; not 1.
(Fide Berggren, 1962) .
1957, Racemiguembelina fructicosa (Egger), Gallitelli, U.S. Nat. Mus.,
Bull, No. 215, p. 142, pl. 32, figs. 14a-15b.
1959. Pseudotextularia varians Rzehak, Liszkowa, Instut. Geol., Bull.
131, p. 66, pl. 5, figs. da-6b. (Fide Berggren, 1963) .
1959, Peenidotestilaria fructicosa (Egger) , Sieglie, Assoc, Mex, Geol.
Petrol., Bol. vol. 11, p. 56, pl. 2 2. figs. 3a, b; 5a, b.
1959. Racemiguembelina fructicosa (Egger), Olvera, Tesis Profesional,
Univ, peaaees Aut, de Mexico, Facultad de Ciencias, Dept.
Biol, pp, 16, pl. 2, figs. 5-7, ane
1961, Race eee fructicosa (Egger) , Said and Kerdany, Micro-
paleont,, Voll v7; No 3. p) 334" pli 2: fig. Vis
1962. Pseudotextularia (Racemiguembelina) fructicosa (Egger) , BE
gren, Stockholm Contr, Geol,, vol. 9, No, 1, pp. 22-24, pl. 6, figs,
6a-b
1964, Racemiguembelina fructicosa (Egger), Loeblich and Tappan,
Treatise of Invert, Paleont., Pt, C, Protista 2, vol, 2, p, C656, fig,
525: 8a-b,
Remarks.—The specimen figured by Egger (1895) in
figures 8 and 9 is designated the lectotype of Guembelina
fructicosa Egger. The depository of Egger’s specimens is un-
known (cf. Ellis and Messina, Catalogue of Foraminifera) .
If Egger’s types cannot be located in the near future, it is
suggested that a neotype be selected from European ma-
terial.
Racemiguembelina fructicosa is one of the most dis-
tinctive and important guide fossils in the Upper Creta-
ceous. The coarseness and widely spaced nature of the costae
and the conical nature of the test suggest that this species
evolved from a Pseudotextularia deformis (Kikoine) an-
cestor. Transitional forms have been noted by the writer in
the Méndez shale of Mexico, Pseudotextularia elegans
(Rzehak) has finer costae and a much more lobulated test
when seen in peripheral view. In addition it is usually rare
in strata assignable to the upper portion of the G. gansseri
subzone whereas P. deformis (Kikoine) is often profusely
abundant. It is not likely that R. fructicosa would evolve
from a species which was near extinction and had a greatly
reduced breeding population,
Range.—G.
upper part of the G. gansseri subzone to A. mayaroensis
contusa—stuartiformis assemblage zone:
subzone.
Occurrence.—In_ Mexico Racemiguembelina fructicosa
has been found during the course of this study in the Mén-
dez shale at numerous localities in the A. mayaroensis sub-
zone and at one locality in the Papagallos shale near the
top of the G. gansseri subzone. In ‘Texas it has been found
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 271
only in the Kemp clay. Gallitelli, (1957, pl. 32) figured a
specimen from a Corsicana marl locality. Other workers
such as Stephenson (1941, pp. 14-23; text-fig. 8) assigned
this same locality to the Kemp clay.
Seiglie (1959, p. 56) noted R. fructicosa in the Maestri-
chtian of Cuba and the writer has seen R. fructicosa in the
Upper Maestrichtian (4. mayaroensis subzone) portion of
the Guayaguayare formation of Trinidad. Berggren (1962,
pp. 23, 24) noted R. fructicosa from the White chalk of
Jutland, Denmark.
Its rather wide geographic distribution suggests that R.
fructicosa is both a Boreal and a Tethyan Maestrichtian
species.
Genus PLANOGLOBULINA Cushman, 1927
Type species —Guembelina acervulinoides Egger, 1899.
Remarks.—The diagnoses of Gallitelli (1957, pp. 141,
142) and Loeblich and Tappan (1964, p. C655-656) are
followed herein.
Range.—Uncertain. Rotalipora assemblage zone (?). G.
bulloides assemblage zone to G. contusa-stuartiformis as-
semblage zone. As already noted, one specimen of Planoglo-
bulina sp. was included by Cushman (1938) as a paratype
of Heterohelix moremani (Cushman). Cushman’s type
came from the Eagle Ford group (cf. Text-figure 2) .
Occwrrence.—North America, West
America, North Africa, and Eurasia.
Indies, South
Planoglobulina acervulinoides (Egger)
Plate 87, fig. 14
1899. Guembelina acervulinoides Egger, K, Bayer, Akad, Wiss., Math,—
Naturh, Abt. Abh., KI, 2, vol, 21, p, 36, pl, 14, figs. 17, 18, 20-22
(fig. 20 = lectotype),
1927. Not Planoglobulina acervulinoides (Egger), Cushman, Jour,
Paleont., vol. 1, p. 158 pl. 27, fig. 5,
1929. Not Planoglobulina acervulinoides (Egger), White, Jour,
Paleont., vol. 3, No. 1, p. 33, pl. 4, fig. 6.
1946. Planoglobulina acervulinoides (Egger), Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 111, pl. 47, figs. 12a, b, 13a, b, ? 15a, b;
not I4a, b.
1950, Planoglobulina acervulinoides (Egger), Cushman, U.S, Geol,
Sur., Prof. Paper, No. 221-A, p. 8, pl. 3, fig. 27.
1956, Planoglobulina acervulinoides (Egger) , Said and Kenawy, Micro-
paleont., vol. 2, No, 2, p. 140, pl. 3, fig. 45.
1956. Ventilabrella eggeri glabrata Cushman, Said and Kenawy, Micro-
paleont., vol. 2, No, 2, p. 140, pl. 3, fig, 46,
1956, Ventilabrella eggeri Cushman, Said and Kenawy, Micropaleont.,
vol, 2; No. 2, p. 140, pl. 3, fig. 38.
1960. Not Planoglobulina acervulinoides (Egger), Olsson, Jour. Pale-
ont., vol. 34, No. 1, pp. 28, 29, pl. 4, fig. 12.
1961, Planoglobulina acervulinoides (Egger), Said and Kerdany,
Micropaleont., vol, 7, No, 3, p. 334, pl. 2, fig. 15.
1964, Planoglobulina acervulinoides (Egger), Loeblich and Tappan,
Treatise on Invert, Paleont., pt. C, Protista 2, vol, 2, pp, C655,
656, fig, 525: 4.
1964, Planoglobulina acervulinoides (Egger), Said and Sabry, Micro-
paleont,, vol, 10, No, 3, p, 394, pl. 3, fig, 30, :
Remarks.—Planoglobulina — acervulinoides (Egger)
seems to be closely related to Planoglobulina carseyae
(Plummer). It is likely that it evolved from P. carseyae
as transitional forms are common. It differs from P. glabrata
(Cushman) by having a thicker test with fewer and larger
chambers.
The specimens figured by Cushman (1927) and by
White (1929) from the Méndez shale as P. acervulinoides
are assignable to P. multicamerata de Klasz. Specimens fig-
ured by Said and Kenawy (1956) from the Maestrichtian of
Egypt as Ventilabrella eggeri glabrata Cushman and Venti-
labrella eggeri Cushman are both assignable to P. acervu-
linoides. ‘These specimens are little different morpho-
logically from the specimen figured by Said and Kenawy
(1956) as P. acervulinoides. In addition all of these speci-
mens are from the same locality (No. 6). In 1960 Olsson
figured P. acervulinoides from the Red Bank formation of
New Jersey. His form appears to be P. glabrata (Cushman) .
Olsson (cbid., pp. 28, 29) indicated that his specimens are
compressed laterally. This is a characteristic feature of P.
glabrata. In addition, his figured specimen shows the
smaller, more numerous chambers and flabelliform shape
characteristic of P. glabrata. It is similar to those figured
from the Lower Taylor marl in this report.
Range.—G. contusa—stuartiformis assemblage zone, G.
gansseri subzone (upper part) to A. mayaroensis subzone.
Occurrence.—P. acervulinoides occurs in the Late
Maestrichtian portion of the Méndez shale in the Tampico
Area of Mexico. It is also known from Middle Maestrich-
tian Papagallos shale strata (uppermost part of G. gansseri
subzone) north of Mamulique Pass along the México, D.F.
—Nueyo Laredo Highway. In Texas P. acervulinoides oc-
curs only in the uppermost part of the Kemp clay in Falls
County. It is also known from the Arkadelphia marl of
Arkansas. Outside of the Western Hemisphere, this species
is known from the Maestrichtian of Europe and Africa.
Planoglobulina carseyae (Plummer)
Plate 87, figs. 10, 15, 16
1931, Ventilabrella carseyae Plummer, Univ, Texas Bull, 3101, p, 178,
pl. 9, figs. 7-9.
1936, Ventilabrella carseyae Plummer, Jennings, Bull, Amer, Paleont,,
vol, 23, No. 78, p. 28, pl. 3, figs. 13a, b.
1938. Ventilabrella carseyae Plummer, Cushman, Contr. Cushman Lab.
Foram, Res,, vol, 14, p. 26, pl. 4, figs, 20-24,
1938. Ventilabrella carseyae Plummer, Cole, Florida Dept. Cons., Geol,
Bull., No. 16, p. 34, pl. 3, figs. 7, 8.
1941, Ventilabrella carseyae Plummer, Cushman and Hedberg, Contr,,
Cushman Lab, Foram, Res., vol, 17, p, 93, pl. 22, figs. 18a, b.
1948. Ventilabrella carseyae Plummer, Cushman and Todd, Contr.
Cushman Lab, Foram, Res., vol, 19, p. 65, pl. 11, fig. 18.
1946, Ventilabrella carseyae Plummer, Cushman, U.S, Geol, Sur,, Prof,
Paper, No, 206, p. 112, pl. 48, figs. la, b, 5a, b,
272 PALAEONTOGRAPHICA AMERICANA (V, 37)
1953. Ventilabrella carseyae Plummer, Loeblich, Contr, Cushman
Found, Foram, Res,, vol, 2, No, 3, p, 109, pl. 12, figs. 6-8.
1957, Planoglobulina carseyae (Plummer), Gallitelli, U.S, Nat, Mus.,
Bull., No. 215, pl. 32, fig. 13.
1960, Planoglobulina carseyae (Plummer) , Olsson, Jour, Paleont., vol,
34. No, 1, p. 29, pl. 4, fig. 13.
Remarks.—The writer has examined Plummer’s types
(Nos. 20808-10) at the Paleontological Research Institution,
Ithaca, New York. The holotype (Plummer, figs. 8a, b) is
unquestionably assignable to Planoglobulina, The paratypes
represent the Heterohelix and Planoglobulina stages of de-
velopment. At present, P. carseyae (Plummer) is regarded
as a valid species. However, it should be borne in mind that
Plummer’s holotype could be regarded as an immature
form of P. acervulinoides (Egger) . There is little doubt that
P. carseyae and P. acervulinoides are closely related. Transi-
tional forms are common. Future workers may wish to re-
gard P. carseyae as a junior synonym of P. acervulinoides
and place the Heterohelix stage of P. carseyae in a new
species.
Range.—G. contusa—stuartiformis assemblage zone: G.
gansseri subzone— (?) A. mayaroensis subzone.
Occurrence.—This species has been found in strata
(MX 174; see Appendix) ,
which are assigned to the Papagallos shale. To date, it has
north of Monterrey, Mexico
not been found in the Méndez shale south of Monterrey.
In Texas P. carseyae occurs in the Corsicana marl and
Kemp clay. In Arkansas it occurs in the Arkadelphia marl.
In addition to the units mentioned above, Cushman (1946,
p. 112) noted P. carseyae in the Nacatoch sand of ‘Texas
and in the Prairie Bluff chalk of Mississippi and Alabama.
Olsson (1960, p. 29) noted this species in the Navesink,
Redbank, and New Egypt formations of New Jersey.
Most of the occurrences in the writer's samples repre-
sent the so-called “Heterohelix stage” of development.
Planoglobulina glabrata (Cushman)
Plate 88, figs. 12, 13, 17
1938. Ventilabrella eggeri var. glabrata Cushman, Contr. Cushman
Lab, Foram, Res,, vol, 14, p. 26, pl. 4, figs, 15-17,
1946, Ventilabrella eggeri Cushman, Cushman, U.S, Geol, Sur,, Prof,
Paper, No, 206, p, 111, pl. 47, figs, 17-19,
1946. Ventilabrella eggeri Cushman var. glabrata Cushman, U.S. Geol.
Sur., Prof, Paper, No, 206, p. 111, pl. 47, figs, 20-22.
1957. Planoglobulina glabrata (Cushman) , Gallitelh, U.S. Nat. Mus.,
Bull, No, 215, pp. 141, 142, pl. 32, figs. 10-12.
1960, Planoglobulina acervulinoides (Egger), Olsson, Jour, Paleont,,
vol. 34, No, 1, pp. 28, 29, pl. 4, fig. 11.
1962, Planoglobulina glabrata (Cushman), Pessagno, Micropaleont.,
vol, 8, No, 3, p. 358 (not figured) ,
Remarks.—P. glabrata (Cushman) differs from P. acer-
(Egger)
multiserial chambers, and by having a much more com-
vulinoides by having smaller, more numerous,
pressed test.
As noted by Gallitelli (in Loeblich, et al., 1957, p. 142),
Ventilabrella eggeri Cushman was erected without the selec-
tion of a holotype, paratypes, or a type locality. No type
specimens of I’. eggert are present in the Cushman Collec-
tion at the U.S. National Museum.
The holotype and paratypes of P. glabrata (Cushman) ,
deposited in the Cushman Collection (USNM), were ex-
amined during the course of this study. In addition, a great
deal of topotypic material from the “Lower Taylor” of
Palmer, Texas, was examined.
Range.—G. bulloides assemblage zone, G. fornicata
subzone to G. fornicata—stuartiformis assemblage zone, G.
elevata subzone (P. elegans zonule). Possibly higher.
Occurrence.—In the present study P. glabrata has been
observed in the Austin chalk (“Hutchins chalk” member) ,
the “Lower Taylor marl”; and the Wolfe City sand of
Texas and in the Brownstown marl of Arkansas. In ‘Texas
P. glabrata is profusely abundant in the “Lower ‘Taylor
marl.’ The Austin occurrence (0-1, see Appendix) is from
the upper four feet of this unit at Dallas, Texas, at a hori-
zon showing Early Campanian or Taylorian reworking
(Text-figure 2). Cushman (1946, p. 112) noted P. glabrata
from the Gober ‘Tongue of the Austin chalk, the “Lower
Taylor marl,” and from the Neylandville marl. The writer
has never found P. ¢’abrata to be abundant in units above
the “Lower Taylor marl” and has never found it to occur
in units above the Wolfe City sand. Numerous samples
collected from the “Upper Taylor marl” were found to
lack P. glabrata, for example. The form figured by Olsson
from the Red Bank formation of New Jersey as P. acer-
vulinoides (Egger) (Cushman) .
Olsson’s Redbank occurrence seems anomalous with the
is actually P. glabrata
writer's Gulf Coast data and may represent a reworked
specimen.
Pessagno (1962, pp. 354-355, 358, Charts 2 and 4) noted
occurrences of P. glabrata in the Cariblanco formation and
in the Rio Yauco formation of Puerto Rico. ‘Two of his
four localities in the Cariblanco formation: OP 2100 and
OP 2196 occur in the upper part of the G. fornicata subzone.
The other two localities: OP 200 (definitely) and OP 45
(probably) occur in the A. blowi subzone, D. multicostaia
zonule. The specimen from the Rio Yauco formation (OP
2690)
multicamerata (de Klasz) .
was reexamined and found to be referrable to P.
Planoglobulina multicamerata de Kiasz
Plate 89, fig. 15
1927, Planogiobulina acervulinoides (Egger), Cushman, Contr, Cush-
¢ ie Snr: = 9 OT 2
man Lab, Foram, Res,, vol. 2, pt. 4, p. 77.
GuLF CRETACEOUS FORAMINIFERA: PESSAGNO 973
1929. Planoglobulina acervulinoides (Egger), White, Jour, Paleont,,
vol. 3, p. 33, pl. 4, fig. 6.
1953. Planoglobulina multicamerata de Klasz, Geol, Bavarica, No. 17,
p. 230, pl. 5, figs. la-b.
Remarks.—Planoglobulina mutlticamerata de Klasz
differs from Planoglobulina glabrata (Cushman) by not
having as pointed an apical extremity in the early part of
its test and by having a less lobulate, larger test with more
numerous chambers. Furthermore, the surface of its test is
covered with medium papillae rather than with costae.
Range.—G. fornicata—stuartiformis assemblage zone,
G. clevata subzone (P. elegans zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence.—P. multicamerata de Klasz has been ob-
served at numerous Maestrichtian and Upper Campanian
localities in the Méndez shale of México. It is usually rather
common in Méndez strata of this age. In Texas P. multi-
camerata has been observed at one locality from the lower
part of the Wolfe City sand (TX 255-A; see Appendix) of
McLennan County.
De Klasz (1953, p. 230) originally described P. multi-
camerata from the Upper Maestrichtian Gerhardtsreuter
beds in Upper Bavaria, southeast Germany. He also noted
that it occurs in the upper part of the Lower Maestrichtian
(2=Middle Maestrichtian, this paper) in the Gerhardts-
reuter beds and in the upper part of the Bucheck beds, as-
sociated with Pseuwdotextularia intermedia de Klasz and
Planoglobulina acervulinoides (Egger). De Klasz also noted
P. multicamerata in the type Méndez shale at Méndez Sta-
tion in México (dA.mayaroensis subzone, MX 206; Ap-
pendix) and in the Maestrichtian of Gan, Basses—Pyrénées
dept., southwestern France.
Family PLANOMALINIDAE Bolli, Loeblich, and Tappan, 1957
Type genus.—Planomalina Loeblich and ‘Tappan, 1946.
Remarks.—The diagnosis of Loeblich and Tappan
(1964, p. C656) is accepted herein.
As noted before, the origin of the Planomalinidae is
still uncertain. However, it seems likely that they evolved
from the Rotaliporidae. For example, the shift in primary
aperture from an extraumbilical-umbilical to an equatorial
position and the shift in coiling from trochispiral to plani-
spiral would not be an insurmountable morphological
change in a low-spired Hedbergella parent stock.
The phylogeny of the Planomalinidae at the generic
level is indicated in Text-figure 8.
Range.—Aptian to Maestrichtian.
Occurrence.—W orld-wide.
ee
= Far <8% Text — Figure 8: Phylogenetic Relationships of Upper Cretaceous
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Lol Je |
* Biglobigerinella Lalicker is regardedas an artificial genus
+= extinction. Swellings in life lines indicate times of greater abundance and speciation
Genus HASTIGERINOIDES Bronnimann, 1952
Type species—Hastigerinoides alexandert Cushman,
1931.
Remarks.—TVhe diagnoses of Bolli, et al., (1957, pp. 24,
25) and Loeblich and ‘Tappan (1964, p. C658) are fol-
lowed herein.
Range.—Aptian—Early Campanian.
Occurrence.—North America, West Indies, and Eurasia.
Hastigerinoides alexanderi (Cushman)
Plate 60, fig. 6
1931, Hastigerinella alexanderi Cushman, Contr, Cushman Lab,
Foram, Res,, vol, 7, p. 87, pl. 11, figs. 6-9.
1946, Hastigerinella alexanderi Cushman, Cushman, U.S, Geol, Sur,,
Prof. Paper, No. 206, p. 148, pl. 61, figs. 4-7.
1952. Hastigerinella (Hastigerinoides) alexanderi Cushman, Bronni-
mann, Bull, Amer, Paleont,, vol, 34, No, 140, pp. 53, 54, text-
fig, 28 (a-m),
974 PALAEONTOGRAPHICA AMERICANA (V, 37)
1957, Hastigerinoides alexanderi (Cushman), Bolli, et al., U.S, Nat,
Mus,, Bull., No, 215, p, 24, pl. 1, figs. 7a-10b,
1964, Hastigerinoides alexanderi (Cushman) , Loeblich and Tappan,
Treatise on Invert, Paleont., pt. C, Protista 2, vol, 2, p. C658,
fig. 526; 2a, b.
Remarks.—The holotype and paratype (Cushman Col-
lection, USNM) of H. alexanderi were examined during
the course of this study. The holotype is refigured herein.
Range.—G. bulloides assemblage zone; M. concavata
subzone on basis of present data.
Occurrence.—In this study H. alexanderi has only been
observed at one Texas locality in the Austin chalk (TX 55,
Rio Grande Area, Kinney Co., Texas; see Appendix).
Here it occurs with Marginotruncana concavata (Brotzen) ,
Globotruncana lapparenti Brotzen 5.5. Globotruncana
fornicata Plummer, Heterohelix reusst (Cushman), and
other species characteristic of the M. concavata subzone in
Texas.
Cushman (1946, p. 148) originally described H. alex-
anderi from the Austin chalk in Grayson County, Texas.
He also noted its occurrence in the Bonham marl of Gray-
son County, ‘Texas.
Bronnimann (1952, frontispiece) noted H. alexander
(Cushman) in the “Turonian—Senonian” of ‘Trinidad.
Hastigerinoides watersi (Cushman)
Plate 51, figure 5; Plate 71, figures 1, 2
1931, Hastigerinella watersi Cushman, Contr, Cushman Lab, Foram,
Res,, vol. 7, p. 86, pl. 11, figs, 4, 5.
1946, Hastigerinella watersi Cushman, Cushman, U.S. Geol, Sur., Prof,
Paper, No, 206, p. 148, pl. 61, figs, 8a-c, 9,
1957, Hastigerinoides watersi (Cushman), Bolli, et, al., U.S. Nat, Mus,,
Bull,, No, 215, pp. 24, 25, pl. 1, figs. 6a-6b,
1964, Hastigerinoides watersi (Cushman), Loeblich and Tappan,
Treatise on Invert. Paleont., Pt. C, Protista 2, vol. 2, p. C658,
fig. 526: Nos, 3a, b,
Remarks. — The holotype (Cushman Collection,
USNM) of H. watersi was examined during the course of
this study. Both the holotype and the specimen figured
herein are coarsely perforate.
Range and occurrence.—H. watersi has only been found
during the course of this study in the “Lower ‘Taylor marl”
(TX 244, see Appendix) . Cushman (1946, p. 148) noted it
in the lower part of the Austin chalk and in the Bonham
marl of Grayson County, northeast ‘Texas. It is probable
that its range is G. bulloides assemblage zone to G. forni-
cata—stuartiformis assemblage zone, A. blow: subzone.
Genus GLOBIGERINELLOIDES Cushman and Ten Dam, 1948
Type species —Globigerinelloides algeriana Cushman
and Ten Dam, 1948.
1948. Globigerinelloides Cushman and Ten Dam, Contr. Cushman
Lab, Foram, Res., vol. 24, pp. 42, 43, pl. 8, figs. 4-6,
1948, Biglobigerinella Lalicker, Jour, Paleont,, vol, 22, p. 624, pl. 92,
figs, 1-3,
1956, Biticinella Sigal, Soc, Géol, France, Comptes Rendus Somm,
Seance, Nos, 3-4, pp. 35-57.
1957. Biglobigerinella Lalicker, Loeblich, et al., U.S. Nat. Mus. Bull,
No. 215, p. 25, pl. 1, figs. 11-12b.
1964, Biglobigerinella Lalicker, Loeblich and Tappan, Treatise on
eee Paleont., pt. C, Protista 2, vol, 2, pp, C656-658, fig. 526:
5a b
)
Remarks.—As noted by Berggren (1962, p. 45), Biglo-
bigerinella Lalicker is an artificial genus. Berggren (ibid.)
stated: “The development of a biserial sequence of cham-
bers within a single population from planispiral forms with
a uniserial set of chambers was demonstrated in strata as
early as Aptian in age by Loeblich and Tappan (1957b, p.
25, pl. 1, figs. 13-18b). It is the writer’s opinion that the
holotype (CC 51898) and figured paratypes (CC 51899 and
51900) and numerous unfigured paratypes (CC 51897) of
Biglobigerinella multispina Lalicker represent the sub-
jectively chosen adult stages of a species belonging to the
Planomalina (Globigerinelloides) group”. Hence, in this
paper the presence of biserial chambers with paired aper-
tures is regarded as a characteristic of adult or gerontic
individuals belonging to certain species of Globigerinel-
loides.
The artificial nature of “Biglobigerinella” can be gra-
phically demonstrated by examining Text-figure 8. From
examining the stratigraphic distribution of Biglobigeri-
nella” it can be seen that species belonging to this genus are
present only during Aptian, Campanian, and Maestrichtian
times. The Campanian—Maestrichtian species, “B.” multt-
spinata Lalicker (includes Globigerinella biforaminata
(Hofker) , is in no way related to Aptian species such as
“B.” barri Bolli, et al. (1957), p. 25, pl. 1, figs. 13-18b) . Fur-
thermore, the present study indicates (1) there are no
known occurrences of Biglobigerinella in strata of Ceno-
manian to Campanian age and (2) that “B.” multispinata
is not descended from a biglobigerinellid ancestor, but ra-
ther from Globigerinelloides prairiehillensis Pessagno, n. sp.
In summary, if one maintains that Biglobigerinella is a
valid genus, he is faced with the perplexing problem that
the Early Cretaceous stock is clearly unrelated phylogeneti-
cally to the Campanian—Maestrichtian stock and that both
Aptian and Maestrichtian species are descended inde-
pendently from different species of Globigerinelloides.
Globigerinelloides asperus (Ehrenberg)
Plate 60, figures 4, 5
1854, Phanerostomum asperum Ehrenberg, Microgeologie, p. 23, pl.
30, figs, 26a-b (designated lectotype herein) ; pl. 32 (gp, 1) fig.
24: pl. 82 (gp. 2), fig. 24; pl. 32° (gp. 2), fig. 42:
1854. Not Rotalia aspera Ehrenberg, Microgeologie, p. 24, pl. 23, fig.
28; pl. 27, figs. 57-58; pl. 28, fig. 42; pl. 31, fig. 44,
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
Description.—Test small, hispid, planispiral consisting
of two whorls; six chambers in the last whorl. Chambers ex-
panding moderately rapidly in size as added. Aperture in-
teriomarginal, equatorial in position, a highly arched
rounded opening bordered by a thick lip. Outer wall radial
hyaline perforate; septal wall microgranular hyaline, per-
forate.
Remarks.—When Ehrenberg (1854, p. 23)
Phanerostomum asperum, he failed to designate both a
definite type locality and a type depository. His figured
specimens are from North America (fig. 24, Missouri ‘Terri-
tory; fig. 42, Mississippi Territory) and from Europe (Insel
Rugen, Deutschland, figs. 26a-b) .
Dr. William A. Berggren (Woods Hole Oceanographic
Institute) recently informed the writer that Ehrenberg’s
types for Phanerostomum asperum are deposited at the
Humboldt Museum in East Berlin (Invalidenstrasse 44) .
To stabilize the taxonomic problems centering around P.
asperum Ehrenberg, the syntypic specimen represented by
plate 30, figures 26a, b is designated a lectotype. Ehrenberg
definitely showed a planispiral form with an equatorial
figured
aperture in his illustrations of this syntypic individual.
Rotalia aspera Ehrenberg (1854) cannot be placed
with any certainty in Globigerinelloides. Ehrenberg only
showed side views of Rotalia aspera in all of his figures.
From his illustrations it is impossible to ascertain whether
his specimens represent planispiral individuals assignable
to Globigerinelloides or trochispiral individuals assignable
to Hedbergella or Archacoglobigerina.
Globigerinelloides asperus (Ehrenberg) c.f. Plate 60,
figs. 2, 3, 4, 5) differs from Globigerinelloides prairiehillen-
sis Pessagno, n. sp. (1) by possessing a smaller, higher, and
more rounded aperture and (2) by showing chambers
which do not increase as rapidly in size.
Occurrence.—In the present study G. asperus was noted
in Mexico in the Coniacian, Santonian, and early Cam-
panian portions of the San Felipe formation and in the
early Campanian portions of the Méndez shale.
In Texas it occurs in the Coniacian portion of the
Austin chalk in Val Verde and Travis Counties and in the
Santonian portion of the Austin chalk in Kinney, Travis,
McLennan, and Dallas Counties.
Globigerinelloides bentonensis (Morrow)
Plate 76, figures 10-11
1934, Anomalina bentonensis Morrow, Jour, Paleont., vol, 8, No, 2
p. 201, pl. 30, figs, 4a, b.
1940. Anomalina bentonensis Morrow, Cushman, Contr, Cushman Lab,
Foram, Res,, vol, 16, p. 28, pl. 5, figs, 3a, b.
1946. Anomalina bentonensis Morrow, Cushman, U.S, Geol, Sur,,
Prof, Paper, No, 206, p. 154, pl. 63, figs, 7a-b,
,
no
~I
Sr
1961, Globigerinelloides bentonensis (Morrow) , Loeblich and Tappan,
Micropaleont., VON. INO. 3p) 2670 pl. 2, figs, 8-10,
Range.—Rotalipora s.s. assemblage zone.
Occurrence.—Several specimens of G. bentonensis (Mor-
row) were found in the San Felipe formation at Boca
Canyon (MX 130, see Appendix) and at Mamulique Pass
(MX 156, see Appendix) to the south and north respect-
ively of Monterrey, Mexico. The writer has also observed
specimens of G. bentonensis in the Cenomanian portion of
Chispa Summit formation at Chispa Summit, Jeff Davis
County, Texas.
G. bentonensis was originally described by Morrow
(1934) from the Hartland member of the Greenhorn
limestone of Kansas. Loeblich and Tappan (1961, p. 268)
indicated that the Greenhorn limestone is of Late Ceno-
manian age. The same authors also noted this species in
the Grayson formation (Del Rio clay) of Texas and in
Cretaceous sediments from the Blake Plateau escarpment
north of Great Bahama Island (Lamont Geological Ob-
servatory Core A167-25) .
Globigerinelloides bollii Pessagno, n, sp.
Plate 62, figure 5; Plate 81, figures 7-8; Plate 97, figures 1-2;
Plate 100, figure 3
Description.—Test planispiral, lobulate, biumbilicate
with six to seven somewhat compressed chambers in the last
whorl. Chambers of earlier whorls spherical; chambers of
last whorl ovoidal, expanding gradually in size. Test sur-
face smooth, polished, and finely perforate; never spinose or
papillose. Sutures straight, radial, and somewhat depressed.
Umbilici large and shallow. Primary aperture equatorial
in position; a moderately high arch at the base of the last
chamber, leading into both umbilical areas. Relict aper-
tures well developed near the suture junctions to umbilicus;
covered by flaplike structures.
Outer wall structure radial hyaline perforate. Relict
apertural flaps and septal walls microgranular hyaline.
Remarks.—Globigerinelloides bollii Pessagno, n. sp.
differs from Globigerinelloides prairichillensis Pessagno, n.
sp. (1) by having a smooth, polished rather than papillose
test wall; (2) by having a more compressed test with
chambers which only gradually increase in size; (3) by
having shallow rather than deep umbilici; (4) by having a
more highly arched primary aperture; and (5) by being
smaller in size.
G. bollii, n. sp. is somewhat similar to G. ehrenberge
(Barr). It differs from G. ehrenbergi by having a more
compressed, polished test with a higher equatorial aperture.
276 PALAERONTOGRAPHICA AMERICANA (V, 37)
Globigerinelloides bollii, n. sp. is named for Dr. Hans
M. Bolli in honor of his great contributions to micro-
paleontology and to the geology of the Caribbean Region.
Type locality—TX 291-C. Taylor formation (“Upper
Taylor marl” member) . Buff, calcareous mudstone breaking
with conchoidal fracture. Sample collected from ditch
i
crossing State Route 73; 2.4 miles east of intersection of
Route 73 with Farm Road 757
Limestone County, Texas.
Deposition of types.—The holotype and the figured
in town of Prairie Hill,
paratypes of G. bollii, n. sp. will be deposited in the col-
lections of the U.S. National Museum, Washington, D.C,
Unfigured paratypes will be deposited at the Paleontologi-
cal Research Institution, Ithaca, N.Y.
Known range.—G. fornicata—stuartiformis assemblage
zone, G. elevata subzone, G. calcarata zonule.
Occurrence.—In the course of this study, G. bollii was
noted only in the
Méndez shale of Mexico.
Upper Taylor marl” of Texas and the
Globigerinelloides caseyi (Bolli, Loeblich, and Tappan)
Plate 49, figures 2-5
1927, Not Anomalina eaglefordensis Moreman, Jour, Paleont,, vol, 1,
Peo pls LG wie Os
1940, Not Planulina eaglefordensis (Moreman), Cushman, Contr,
Cushman Lab, Foram, Res., vol, 16, p. 32, pl. 6, figs, 4, 5,
1946, Not Planulina eaglefordensis (Moreman), Cushman, U.S, Geol,
Sur,, Prof, Paper, No, 206, p, 156, pl. 64, figs, Ba-c, 9.
1957. Planomalina caseyi Bolli, Loeblich, and Tappan, U.S. Nat. Mus.,
Bull, No, 215, p. 24, pl. 1, figs. 4a-5b,
1961, Globigerinelloides eaglefordensis (Moreman) , Loeblich and Tap-
pan, Micropaleont,, vol, 7, p, 268, pl. 2, figs. 3a-7b.
1962, Globigerinelloides eaglefordensis (Moreman), Ayala, Soc, Geol,
Mexicana, Bol., vol. 25, No, 1, pp, 15, 16, pl. 1, figs. 2a-c; pl.
6., figs. 2a, b, 3a, b.
1964, Globigerinelloides eaglefordensis (Moreman) , Loeblich and ‘Tap-
pan, Treatise on Invert. Paleont,, pt, C, Protista 2) vol. 2 pp:
C657-658, fig. 526: 7a, b.
1964, Globigerinelloides caseyi (Bolli, Loeblich, and Tappan), Low,
Contr, Cushman Found, Foram, Res,, vol, 15, pt. Seppe 22 ml23t
Known range.—G. fornicata—stuartiformis assemblage
Abstract): “Anomalina ceaglefordensis Moreman is a
benthonic species, now questionably assigned to the genus
Planulina. Planktonic specimens formerly referred to it
belong in Globigerinelloides caseyi (Bolli, Loeblich, and
Tappan, 1957) .”
Through the kindness of Doris Low and Ruth Todd,
the writer was able to examine the holotype of Anomalina
eaglefordensis Moreman (Texas Christian University, Fort
Worth, Texas) while it was on loan to Doris Low. There is
no question about A. eaglefordensis Moreman being a
benthonic species. The assignment of G. casey: (Bolli, Loe-
blich, and Tappan) to this species by Loeblich and ‘Vappan
(1961, 1964) and by Ayala (1962) is incorrect.
Range.—H. washitensis assemblage zone to Rotalipora
s.§. assemblage zone, R. cushmani—greenhornensis subzone.
Occurrence.—In the course of the present study G.
caseyt has been observed in the San Felipe formation (MX
128 and MX 130, see Appendix) at Boca Canyon, somewhat
to the south of Monterrey, Mexico. The fauna at MX 128
is assignable to the R. cushmani—greenhornensis subzone.
It contains Rotalipora greenhornensis (Morrow), Rotali-
pora cushmani (Morrow), Hedbergella amabilis Loeblich
and ‘Tappan, Hedbergella brittonensis Loeblich and ‘Tap-
pan, Heterohelix moremani (Cushman), and other com-
ponents of the R. cushmani—greenhornensis subzone. MX
130 occurs in the basal portion of the M. helvetica assem-
blage zone, M. sigali subzone. It contains M. marginata
(Reuss). M. sigali (Reichel) , together with reworked (?)
elements such as Rotalipora greenhornensis from the under-
lying Rotalipora s.s. assemblage zone, R. cushmani—
ereenhornensis subzone.
G. caseyi has been observed by the writer in samples
from the Grayson formation (Del Rio clay) and the
Eagle Ford group wherever these units were studied during
the course of this work. G. casey: occurs in the Eagle Ford
group in all formational units which are included within
the Rotalipora assemblage zone [Chispa Summit fm.
(lower portion) ; Boquillas fm.; Lake Waco fm.; and Brit-
ton fm. (part); see Text-figure 2].
Loeblich and Tappan (1961, pp. 268, 269) noted this
species in the Grayson formation and in the Eagle Ford
group (Britton fm.) of Texas as well as in the Gault of
England and in Lamont Geological Observatory subma-
rine core Al67-24 from the Blake Plateau escarpment.
Ayala (1962, p. 6 and pp. 15-16) noted and figured
G. caseyi under the name of G. eaglefordensis from the
Cenomanian of Cuba.
Globigerinelloides ehrenbergi (Barr)
1962, Planomalina ehrenbergi Barr, Paleontology, vol, 4, pt. 4, p. 563,
pl. 69, figs, la-b,
Range.—Uncertain at present.
Occurrence.—Forms assignable to this species were
found in samples from the “Lower ‘Taylor marl” during the
final part of this study.
Globigerinelloides ‘multispina (Lalicker)
Plate 70, figs. 1-2; Plate 82, figs. 10-11; Plate 91, figs. 1-2
1948. Biglobigerinella multispina Lalicker, Jour. Paleont., vol. 22, No.
by pln 92, ties. li-3:
1956, Globigerinella biforaminata Hotker, Natuurh, Maandbl,, vol, 45,
Nos, 5, 6, p. 53, text-figs. 2, 5.
1956, Globigerina biforaminata (Hofker) , Hofker, Paleont, Zeitschr.,
Bd, 30, p. 76, pl. 9, figs, 68a-c; pl, 10, figs, 7la-c,
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 2
1957. Biglobigerina multispina Lalicker, Loeblich, et al., U.S. Nat.
Mus,, Bull., No, 214, p. 24, pl. 1, figs. 11-12b,
1960, Biglobigerinella biforaminata (Hofker) , Olsson, Jour, Paleont.,
vol. 34, No, 1, p. 44, pl. 8, figs. 7, 8.
1962, Planomalina multispina (Lalicker), Barr, Paleontology, vol, 4,
pt. 4, pp. 563-564, pl, 69, figs, 5a, b,
1962. Planomalina (Globigerinelloides) messinae (Bronnimann),
Berggren (part.), Stockholm Contr, Geol,, vol, 9, No. 1, pp. 44-46,
pl. 8, figs. da-c; 6a-c; 8a-c (not 7a-c); text-fig, 6: 2a, b; 5a, b
(not la-b; 3a-e; 4a, b; 6a-c); text-fig, 7: 6a, b; 7a-c; 8a, b (not
la-b; 2a, b; 3a, b; 4a, b; 5a, b).
1964, Globigerinelloides messinae (Bronnimann), Olsson, Micropal-
eont,, vol. 10, No, 2, pp, 174-176, pl. 7, figs, 6a-b; 7a-b; 8a-b,
1964, Biglobigerinella multispina Lalicker, Loeblich and Tappan,
Treatise on Invert, Paleont., pt. C, Protista 2, vol, 2, p. C656,
fig, 526: 4, 5a-b,
Remarks.—As_ noted previously in the discussion of
Globigerinelloides, Biglobigerinella Lalicker is considered
an artificial genus and is not used herein. The presence of
biserial chambers and double apertures is regarded as a
specific rather than a generic characteristic. It is common
to only a few species of Globigerinelloides.
Globigerinella biforaminata Hofker is regarded as
a junior synonym of Globigerinelloides multispina (La-
licker) and simply represents an immature form of this
species. Abundant topotypic samples from the Marlbrook
marl of southwestern Arkansas show both the biapertural,
biserial form like G. multispina (Lalicker) and the uni-
serial biapertural form like G. biforaminata (Hofker) in
intimate association. In fact, both of these forms invariably
occur together throughout the Gulf Coast area in strata of
Maestrichtian and Late Campanian age and have pre-
cisely the same geologic range. Furthermore, if the biserial
chambers are broken or ground away from the test of G.
multispina (Lalicker) , the earlier G. biforaminata stage of
development is clearly visible.
As noted in synonomy aboye, many of the forms fig-
ured by Berggren (1962) and all of the forms figured by
Olsson (1964) as G. messinae s.s. are assignable to G. mul-
tispina (Lalicker). A study of the types of Globigerinel-
loides messinae s.s. Bronnimann at the U.S. National Mu-
seum shows that this species is markedly different morpho-
logically from Globigerinelloides multispina (Lalicker) .
[See G. volutus (White) =G. messinae s.s. (Bronnimann)
herein].
Globigerinelloides multispina (Lalicker) appears to be
derived from G/obigerinelloides prairichiilensis Pessagno,
n. sp. Both species show a rapid expansion of the chambers
in the last whorl especially when seen from edge or peri-
pheral view although G. multispina is more involute in its
coiling. The lineage of G. asperus (Ehrenberg) —G. prairie-
hillensis Pessagno, n. sp.—G. multispina (Lalicker) is sug-
gested.
~I
~I
Range.—G._ fornicata—stuartiformis assemblage zone,
G. elevata subzone, P. elegans zonule to G. contusa—stuarti-
formis assemblage zone, A. mayaroensis subzone. ‘To date,
the writer has not seen this species in Maestrichtian strata
above the G. gansseri subzone. However, Berggren (1962,
text-fig. 6) recorded it from the A. mayaroensis subzone of
Denmark.
Occurrence.—In the course of this study G. multispina
has been found in the Méndez shale of Mexico; the Upson
clay, Wolfe City sand, “Upper ‘Taylor marl,’’ Neylandville
marl, and Corsicana marl of Texas; and in the Ozan for-
mation, Annona chalk, Marlbrook marl, Saratoga chalk,
and Arkadelphia marl of southwestern Arkansas.
Globigerinelloides prairiehillensis Pessagno, n. sp.
Plate 60, figures 2, 3; Plate 83, figures 1; Plate 90, figures 1-2, 4;
Plate 97, figures 3, 4
1962. Planomalina (Globigerinelloides) messinae (Bronnimann) , Berg-
gren (part.), Stockholm Contr, Geol,, vol. 9, No. 1, pp. 44-49,
text-fig. 7:-la, b; 2a,b; ?3ab; ?4a,b; 5a,b (not 6a,a; 7a,b; 8a, b).
y
/
Description.—Test lobulate, biumbilicate, planispirally
coiled, with six to seven chambers in the last whorl. Cham-
bers spherical, rapidly increasing in size particularly when
seen from peripheral view. Umbilici deep and moderately
large. Test covered by fine to medium papillae. Sutures
radial, depressed, straight. Aperture equatorial in position,
a lowly arched opening at the base of the last chamber.
Relict apertures and relict apertural flaps well developed.
Outer wall radial hyaline perforate; septal wall and rebet
apertural flaps microgranular hyaline.
Remarks.—Globigerinelloides prainiehillensis Pessagno,
n. sp. differs from Globigerinelloides asperus (Ehrenberg)
by being larger, showing a more rapid increase in chamber
size, and by having a low aperture at the base of its last
chamber. It differs from Globigerinelloides volutus
(White) (=G. messinae s.s. Bronnimann) by being much
more deeply umbilicate, by having a lowly arched rather
than highly arched aperture, and by showing a much more
rapid increase in chamber size particularly when seen
from peripheral view. Gobigerinelloides pratriehi‘lensis, 0.
sp. differs from Globigerinelloides multispina (Lalicker)
by lacking a bipartite apertural apparatus, by having larger
umbilici, and by being more evolute.
Globigerinelloides prairiehillensis, n. sp. is named after
the town of Prairie Hill, Texas.
Type locality —TX 291-C. Taylor formation (“Upper
Taylor marl” member). Sample collected from a ditch
crossing State Route 73: 2.4 miles east of intersection of
Route 73 with Farm Road 737 in town of Prairie Hill,
Limestone County, ‘Texas,
Deposition of types—The holotype and figured para-
types will be deposited in the collections of the U.S. Na-
tional Museum, Washineton, D.C. Unfigured paratypes
will be deposited at the Paleontological Research Institu-
tion, Ithaca, N:Y.
Range.—G. bulloides assemblage zone, G. fornicata
subzone to G. fornicata—stuartiformis assemblage zone, R.
subcircumnodifer subzone.
Occurrence.—In Texas this species has been observed
in the Austin chalk (Burditt marl and “Hutchins Chalk”
members) , “Lower Taylor marl”, Wolfe City sand, Pecan
Gap cha_k, “Upper Taylor marl’, and the Neylandville
mar). In southwestern Arkansas G. prairichillensis has been
observed in the Brownstown marl, the Ozan formation,
Annona chalk, Marlbrook marl, and Saratoga chalk. In
Mexico G. prairichillensis has been observed in the lower
and middle parts of the Méndez shale. In Puerto Rico the
writer noted G. prairichillensis in samples from the Par-
euera limestone and the R’o Yauco formation.
Globigerinelloides subcarinatus (Bronnimann)
Plate 62, figs. 12-13
1952. Globigerinella messinae subcarinata Bronnimann, Bull, Amer,
Paleont., vol. 34, No, 140, pp. 44, 45, pl. 1, figs, 10, 11; text-
fig, 21: a-m,
1955, Globotruncana (Rugoglobigerina) beldingi subbeldingt Gandolfi,
Bull, Amer, Paleont,, vol, 36, No, 155, p. 32, pl, 1, figs. 7a-c.
1964. Not Globigerinelloides subcarinatus —(Bronnimann), Olsson,
Micropaleont., vol. 10, No. 2, pl. 7, figs. 9a, b 10a, b.
Remarks.—Globigerinelloides subcarinatus (Bronni-
mann) differs from Globigerinelloides volutus (White)
[senior synonym of G. messinae (Bronnimann) | by the
much more compressed nature of its test. Both species are
similar in side view, but in peripheral view the last several
chambers of the final whorl of G. swbcarinatus are ovoidal
and elongate in shape whereas those of G. volutus (White)
are less ovoidal and are nearly spherical.
‘The writer has examined the holotype and paratypes
of G. subcarinatus at the U.S. National Museum, Wash-
ington, D.C., and has likewise examined the holotype of
Globotruncana
Gandolfi (No. 20829) at the Paleontological Research Ins-
titution, Ithaca, New York. Gandolfi’s species is plani-
spirally coiled, shows an equatorial aperture, and_ lacks
keels and meridorially arranged rugosites. Thus, it cannot
logically be assigned either to Globotruncana or to Rugo-
(Rugoglobigerina) beldingi subbeldingi
globigerina. The compressed nature of its test and the high-
ly ovoidal nature of its final chambers indicate Gandolfi's
species is a junior synonym of G. subcarinatus (Bronni-
mann).
The specimens figured by Olsson as G. subcarinatus
(Bronnimann) (1964, pl. 7, figs. 9a, b; 10a, b) are closely
278 PALAEONTOGRAPHICA AMERICANA (V, 37)
allied to G. volutus White. G. subcarinatus (Bronnimann)
seems to have evolved from the longer ranging G. volutus
(White) . Transitional forms are often common.
Range.—G,_ fornicata—stuartiformis assemblage zone,
G. clevata subzone (G. calcarata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayarocnsis subzone.
Occurrence.—Globigerinelloides subcarinatus has only
been observed in the Méndez shale of Mexico. It is most
common in strata assignable to the A. mayaroensis subzone.
sronnimann originally described this species from the
Guayaguayaie formation of Trinidad in strata which are
assignable to the A. mayaroensis subzone.
Globigerinelloides volutus (White)
Plate 62, figures 9-11; Plate 100, figure 9
1928, Globigerina voluta White, Jour, Paleont,, vol, 2, No, sh, pp.
197, 198, pl. 28, figs, 5a, b.
1952. Globigerinella messinae messinae Bronnimann, Bull, Amer,
Paleont., vol. 34, No, 140, pp. 42-44 pl. 1, figs. 6, 7; text-fig,
20: a-q.
1955, Globotruncana (Rugoglobigerina) beldingi beldingi Gandolfi,
Bull, Amer, Paleont,, vol, 36, No, 155, p. 31, pl. 1, figs. 8a-c,
1960, Globigerinella messinae subcarinata (Bronnimann), Olsson,
Jour, Paleont,, vol, 34, No, 1, pp. 43, 44, pl. 8, figs. 9, 10,
1962, Planomalina — (Globigerinelloides) — messinae — (Bronnimann) ,
Berggren (part), Stockholm Contr, Geology, vol, 9, No, 1, pp.
44-46; text-fig. 6: la, b; 3a-e; 4a-c; 6a-c (not 2a, b; 5a, b); text
fig. 7: ?la,b; ?3a,b; ?74a,b (not 2a, b; 5a, b; 6a, b; 7a-c; 8a, b);
plate 8, not figs. 4a-8b.
1964, Globigerinelloides subcarinatus (Bronnimann), Olsson, Micropal-
eont., vol. 10, No. 2, pp. 176-178, pl. 7, figs. 9a-10b.
(White) was
originally described by White from the type locality of the
Remarks.—Globigerinelloides volutus
Méndez shale at Méndez Station (Tampico—Ciudad Valles
Railroad, MX 206; see Appendix). A sample of type Mén-
dez shale, given to the writer through the kindness of W.
Storrs Cole, Cornell University, indicates (1) that the
faunal assemblage of this locality is assignable to the A.
mayaroensis subzone and (2) that only two species of
Globigerinelloides: G. messinae (Bronnimann) and G. swb-
carinatus (Bronnimann) occur. Dr. John Imbrie of Colum-
bia University has informed the writer that White's types
are missing from the Columbia University Paleontology
Collection. If these types are not located in the near future,
a neotype will have to be erected from the Méndez Station
material. Although White's drawings of G. volutus are not
accurate, it seems obvious from a comparison of the topo-
typic material with the holotype and paratypes of G. mes-
sinae s.s. (Bronnimann) (USNM) that G. volutus (White)
is a senior synonym of G. messinae 5.5. (Bronnimann) .
Globigerinelloides volutus (White) differs from Glo-
bigerinelloides subcarinatus (Bronnimann) by the more
inflated, subspherical nature of the chambers in the last
whorl. (The chambers of G. swbcarinatus tend to be elong-
ate and ovoidal in character) .
GULP CRETACEOUS FORAMINIFERA: PESSAGNO 279
G. volutus (White) differs from G. prairichillensis
Pessagno, n. sp. (1) by the more compressed nature of its
test; (2) by the much larger size of its umbilici; (3) by its
smaller, rounded equatorial aperture; and (4) by the grad-
ual increase in the inflation of its chambers when seen in
peripheral view. It differs from G. multispinata (Lalicker)
in characteristics 1, 2 and 4 above and by lacking a bipar-
tite aperture and biserial chambers.
Through the courtesy of Mrs. K. V. W. Palmer the
writer was able to examine the Gandolfi types from
Colombia at the Paleontological Research Institution, in-
cluding the holotype of G!obotruncana (Rugoglobigerina)
beldingi Gandolfi (No. 20830). Globotruncana (R.)
beldingi s.s. is planispirally coiled with an equatorial aper-
ture. It is assignable to Globigerinelloides volutus.
Range.—G. fornicata—stuartiformis assemblage zone, G.
elevata subzone, to G. contusa—stuartiformis assemblage
zone, A. mayaroensis subzone.
Occurrence.—Globigerinelloides volutus (White) (=
G. messinac s.s. Bronnimann) occurs in the Méndez shale
of Mexico; the “Upper Taylor marl”, Neylandville marl,
and Corsicana marl of ‘Texas; and in the Saratoga chalk of
southwestern Arkansas.
The specimens referred to Planomalina messinae s.s. by
Pessagno (1962, p. 354, Chart 2) from the Cariblanco for-
mation of Puerto Rico were rechecked and found not to
be referable to this species.
Globigerinelloides yaucoensis (Pessagno)
Plate 75, figs. 9-10, 27; Plate 97, figs. 5, 6
1960, Planomalina yaucoensis Pessagno, Micropaleont., vol, 6, No, 1,
p. 98) pl. 2) figs. 14-15; pl. 5, fig. 4.
Remarks.—Globigerinel!oides yaucoensis (Pessagno) is
distinguished from Globigerine!loides prairichillensis Pes-
sagno, n. sp. (1) by the gradual and uniform increase of the
size of its chambers; (2) by its finely spinose test surface
(when well preserved); (3) by its shallower and usually
somewhat wider umbilical openings; and (4) by its univer-
sally smaller size.
Range.—G._ fornicata—stuartiformis assemblage zone:
G. elevata subzone (G. calcarata zonule) to R. subcircum-
nodifer subzone (R. swbhpennyi zonule) .
Occurrence.—Globigerinelloides yaucoensis has been
observed in the Méndez shale of Mexico; the “Upper Tay-
lor marl” and Neylandville marl of Texas; and in the An-
nona chalk, Marlbrook marl and Saratoga chalk of south-
western Arkansas. In Puerto Rico the writer observed G.
yaucoensis in the Rio Yauco formation and in the Parguera
limestone,
Family SCHACKOINIDAE Pokorny, 1958
Type genus.—Schackoina Thalmann, 1932.
Remarks.—The diagnosis for this family presented by
Loeblich and Tappan (1964, p. C658) is followed herein.
The Schackoinidae seem closely allied morphologically
to the Planomalinidae because of the nearly planispiral na-
ture of their tests and their possession of an equatorial aper-
ture. However, it is not inconceivable that they evolved
from a rotaliporid stock via a low-spired Hedbergella stage.
Genus SCHACKOINA Thalmann, 1932
Type species—Siderolina cenomana Schacko, 1897.
Remarks.—The diagnosis of Loeblich and ‘Tappan
(1964, p. C658) is followed herein.
Schackoina cenomana (Schacko)
Plate 48, fig. 6
1897. Siderolina cenomana Schacko, Ver. Freundenaturg. Mecklenburg.,
Archiv, voi, 50 (1896) , p. 166, pl. 4, figs, 3-5,
1932, Hantkenina (Schackoina) cenomana_ (Schacko), Thalmann,
Eclogae Geol. Helv., vol. 25, No. 2, p. 288.
1952. Hastigerinoides rohri Bronnimann, Bull, Amer, Paleont., vol, 34,
No. 140, p. 55, text-fig. 29; a-f; pl. 1, figs. 8 9.
1955, Schackoina cenomana (Schacko), Gallitelli, Micropaleont., vol, 1
No, 2, pp. 143, 144,
1957. Shackonia cenomana (Schacko), Bolli, et al., U.S. Nat. Mus.,
Bull., No, 215, p. 26, pl. 2) figs. 1, 2.
1959. Schackoina cenomana (Schacko) , Orloy, et al,, Osnovy, Paleon-
tologil, p, 300, text-fig, 676A, B.
1961. Schackonia cenomana (Schacko), Loeblich and Tappan, Micro-
paleont,, vol, 7, No, 3, pp. 270, 271, pl. 1, figs. 2-7.
1962, Schackoina cenomana_ (Schacko), Ayala, Soc, Géol, Mexicana,
Bol., vol, 25, No. 1, pp. 20, 21, pl. 2, figs. 2a-c; 3a-c; pl. 7, figs.
3a, b; pl. 8, figs. la-c.
1964, Schackoina cenomana (Schacko) , Loeblich and Tappan, Treatise
on Invert, Paleont., pt, C, Protista 2, vol, 2, p, C658, fig, 526;
fa-c, 9.
Range.—Rotalipora assemblage zone. R. cushmani—
greenhornensis subzone.
Occurrence.—In Mexico this species has been observed
in a single sample (MX 133; see Appendix) from the San
Felipe formation at Boca Canyon south of Monterrey
(Text-figures 1, 2). Here it occurs in Lower Turonian
strata (M. helvetica assemblage zone, M. sigali Subzone)
containing reworked (?) Upper Cenomanian elements. In
Texas S$. cenomana was only observed by the writer in the
Upper Cenomanian portion of the Eagle Ford group (Brit-
ton clay, TX 329; see Appendix) .
Loeblich and Tappan (1961, pp. 270-271) noted S.
cenomana in the Britton clay of Texas; the Greenhorn
limestone (Hartland shale member) of Kansas; the Ceno-
manian of the California Coast Ranges; the Cenomanian of
Trinidad; the Cenomanian of Switzerland; and the Ceno-
manian of Germany.
Ayala (1962, pp. 20, 21) recorded $, cenomana from
the Cenomanian of Cuba,
280 PALAEONTOGRAPHICA AMERICANA (V, 37)
Schackoina multispinata (Cushman and Wickenden)
Plate 60, fig. 1
1930, Hantkenina multispinata Cushman and Wickenden, Contr,,
Cushman Lab, Foram, Res., vol. 6, pt. 2, p. 40, pl. 6, figs, 4-6.
1933, Schackoina multispinata (Cushman and Wickenden), Cushman,
Cushman Lab, Foram, Res,, Spec, Publ, No, 5, pl. 35, figs, 9, 10,
1934, Hantkenina trituberculata Morrow, Jour, Paleont,, vol, 8, p. 195,
pli 29) figs! 24° (26-28:
1946, Schackoina multispinata (Cushman and Wickenden) , Cushman,
U.S. Geol. Sur., Prof. Paper, No. 206, p. 148, pl. 61, figs. 11, 12.
1946. Schackoina trituberculata (Morrow), Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 148, pl. 61, figs. 13-16.
1947. Schackoina cenomana (Schacko) subsp, bicornis Reichel, Eclogae
Geol, Helv., vol, 40, No, 2, p. 401, text-figs, 4a-g, 6 (4), 8b, 9,
LOM (S GMS eO 5)
1947, Schackoina moliniensis Reichel, Eclogae Geol, Helvy,, vol, 40,
No, 2, p. 402, text-figs. 5, 6 (5), 7(5), 8c, 10(12), 13; pl. 8, fig. 2.
1955. Schackoina trituberculata (Morrow), Gallitelli, Micropaleont.,
vol. IU No.2, p: 142) pl iy fie i.
1961, Schackoina multispinata (Cushman and Wickenden), Loeblich
and Tappan, Micropaleont,, vol. 7, No, 3, pp. 271, 272, pl. 1
figs, 8-10,
1962, Schackoina mullispinata (Cushman and Wickenden) , Ayala,
Soc. Geol. Mex., Bol., vol. 25, No. 1, pp. 19, 20, pl. 2, figs. la-d;
pl. 7, figs. 2a-b.
’
Range.—Rotalipora s.s. assemblage zone to G. fornicata
—stuartiformis assemblage zone.
Occurrence.—This species seems to be extremely rare in
the Gulf Coast section and has only been noted in the
Méndez shale at MX 80 and MX 82 (see Appendix). Both
of these localities occur in strata assignable to the G. forni-
cata—stuartiformis assemblage zone, G. elevata subzone, G.
calcarata zonule.
S. multispinata was originally described from the Che-
val formation of Manitoba, Canada. Loeblich and ‘Tappan
(1961, p. 272) noted its presence in the Eagle Ford group,
Austin chalk, and Pecan Gap chalk of Texas; in the Hart-
land shale member of the Greenhorn limestone of Kansas;
in the Niobrara formation of Kansas, Nebraska, and South
Dakota; and in the Upper Cretaceous of California. S.
multispinata is also common in the Upper Cretaceous of
Europe.
Family ROTALIPORIDAE Sigal, 1958 emended
1958. Rotaliporidae Sigal, Soc. Geol. France, C. R. Somm., No. 12, p.
264.
1959. Rotalipriinae Sigal, Banner and Blow, Paleontology, vol. 2, pt. 1,
ri8s
1964. Romieoridae Sigal. Loeblich and Tappan, Treatise on Invert.
Paleont., pt. C. Protista 2, vol. 2, p. C659.
Type genus.—Rotalipora Brotzen, 1942.
Emended definition.—Coiling trochospiral; — primary
aperture extraumbilical-umbilical occasionally | spiroum-
bilical. Portici extending from over aperture of each
chamber into umbilical area. Secondary sutural apertures
developed either on spiral or umbilical side of test. Those
on umbilical side open on posterior margin of chambers.
Outer wall bilamellar, radial hyaline perforate except for
keels which are radial hyaline imperforate and spines and
rugosities which are ultragranular hyaline imperforate.
Septal walls microgranular hyaline perforate. Portici micro-
granular hyaline perforate (?) .
Remarks—The definition of Loeblich and Tappan,
1964, has been emended herein largely to accommodate the
inclusion of the Loeblichellinae, Pessagno, n. subfamily.
Loeblichella Pessagno, n. genus, the type genus of the
Loeblichellinae, possesses supplementary sutural (relict?)
apertures on the spiral side of the test and a primary aper-
ture which varies from extraumbilical-umbilical to spiro-
umbilical.
The Rotaliporidae form the basic stock from which
the Planomalinidae, Marginotruncanidae, and possibly the
Abathomphalidae evolved.
The Rotaliporidae themselves may have evolved from
the Heterohelicidae or from some family among the Dis-
corbacea as has been previously suggested herein.
The phylogeny of the Rotaliporidae at the generic
level is summarized in Text-figure 9. It can be readily
demonstrated that Clavihedbergella, Loeblichella, n. gen.,
and Praeglobotruncana evolved from a Hedbergella stock.
Transitional forms have been noted between Hedbergella
and all of the aforementioned genera during the course of
this study.
Clavihedbergella and perhaps Praeglobotruncana ap-
pear to be polyphyletic in character. The Upper Ceno-
manian species, C. simplex (Morrow), arose from Hed-
bergella amabilis. Transitional forms are common in the
Cenomanian portion of the Eagle Ford group. C. moremani
(Cushman) appears to have arisen either directly from H.
amabilis Loeblich and Tappan or from the less clavate C.
simplex (Morrow). Albian species such as C. suwbcretacea
(Tappan) probably evolved from H. delrioensis. Species
of Praeglobotruncana such as P. delrioensis (Plummer)
and P. stephani (Gandolfi) evolved from either a Hedber-
gella delrioensis (Carsey) or possibly a Hedbergella plani-
spira (Tappan) stock through the addition of an imper-
forate peripheral band or a keel. The origin of the highly
carinate species, P. bronnimanni Pessagno, n. sp. is at pres-
ent uncertain.
Numerous transitional forms have been observed in
Eagle Ford strata linking Hedbergella delrioensis (Carsey)
with Loeblichella hessi (Pessagno). L. hessi in turn gave
coarctata (Bolli) (=L. hessi compressiformis
Pessagno) via the compression of its test and the formation
rise to L.
of an angled periphery. L. hessi and L. coartata are the
longest ranging Upper Cretaceous planktonic species known
to the writer. They persist sporadically from Late Ceno-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 981
= ——
”
wile c
= fy ¢ 3] 89%} Text —Figure 9: Phylogenetic Relationship of Upper Cretaceous
Call aS ae Rotaliporidoe at the Generic Level
o| 542] EXD
c| w <
3
ae) Midway -
a Danian ian ae
T
c ?
5 .
= 5
anf
iS 5
7 > +
3 3
8 Zz |
r ?
i]
5 5 !
FS = ?
a <= ol 2
E > = =
3 Fe al 2
g o
a= (aaa
5 ry
oe °
36 =
Upper Cretaceous Series
Coniacian | Santonian
Austinian
ronian
Tu
efordian
ag!
oO +
E
Wood-
binian
Hedbergella
Cenomanian
Praeglobotruncana
Ticinella
Washitian
Clavihedbergella
Lower Cretaceous
Series (Part.)
Fredricksburgian
c
Z
a
‘las
+ = Extinctions
Swellings of life lines = times of greater abundance and speciation
manian to at least Middle Maestrichtian times. Globo-
conusa of the Danian, which also possesses sutural supple-
mentary apertures on the spiral side of its test may have
been derived from a Loeblichella ancestor.
Ticinella appears to have arisen from a Hedbergella
stock through the enlargement of the portici and the de-
velopment of sutural supplementary apertures on the um-
bilical side of the test. Rotalipora may have been derived
from a Ticinella stock via the compression of the test and
the addition of a well-developed peripheral keel or from a
Praeglobotruncana stock via the acquisition of umbilical
sutural supplementary apertures.
The Rotaliporidae were most abundant and varied
during Cenomanian times (Rotalipora s.s. assemblage zone)
(Text-figure 9). During the Turonian and Coniacian (M.
helvetica and M. renzi assemblage zones) they were re-
placed by the Marginotruncanidae. Hedbergella and Clavi-
hedbergella rapidly dwindle in abundance after Coniacian
times and probably become extinct by or before Early
Maestrichtian times (See Globotruncanella, herein). Loe-
blichella persists unchanged throughout most of the Upper
Cretaceous,
Text-figure 10 is a schematic diagram showing a plot
of rotaliporid size with respect to part of Cretaceous time.
It is worth noting that the largest Rotaliporidae (e.g., spe-
cies of Rotalipora s.s.) appeared during the peak of their
evolution in Middle and Late Cenomanian times. Both
earlier and later rotaliporids were smaller in size.
Subfamily HEDBERGELLINAE Loeblich and Tappan, 1961
Type genus.—Hedbergella Bronnimann and Brown,
1958.
Remarks.—The diagnosis of the Hedbergellinae pre-
sented by Loeblich and Tappan (196la, p. 273; 1964, p.
C659) is followed herein. The Hedbergellinae form the
basic stock from which the Rotaliporinae (part?) and the
Loeblichellinae evolved.
Range.—Hautervian to Maestrichtian.
Occurrence.—Cretaceous marine strata; world-wide.
Genus HEDBERGELLA Bronnimann and Brown, 1958
Type species—Anomalina lorneiana dOrbigny var.
trochoidea Gandolfi, 1942.
Remarks.—The diagnosis presented by Loeblich and
Tappan (1916a, p. 273; 1964, p. C659) is followed herein.
Range.—Hautervian to Campanian; Maestrichtian (?).
Occurrence.—Cretaceous; world-wide.
Hedbergella amabilis Loeblich and Tappan
Plate 52, figures 6-8
1952. Globigerina cretacea d’Orbigny, Bronnimann, Bull. Amer. Pal-
eont., vol. 34, No. 140, pp. 14-16, text-figure 3: a-m.
1961. Hedbergella amabilis Loeblich and Yappan, Micropaleont., vol.
7, No. 3, p. 274, pl. 3, figs. 1-10.
1961. Clavihedbergella simplex (Morrow), Loeblich and ‘Tappan
(part) , Micropaleont., vol. 7, No. 3, pp. 279, 280, pl. 3, figs. lla-
c; not 12a-14b.
1962. Clavihedbergella simplex
Mex., Bol., vol. 25, pp. 25, 26, pl. 4,
la-c; pl. 5, figs. la-c.
1963. Hedbergella amabilis Loeblich and Tappan, Renz, Luter-
bacher, and Schneider, Eclogae Geol. Helv., vol. 56, No. 2, p.
1084, pl. 9, figs. 4a-c; 6a-c.
1964. Clavihedbergella simplex (Morrow), Todd and Low, Deep-Sea
Research, vol. 11, pp. 403, 404, pl. 1, fig. 1.
(Morrow), Ayala (part), Soc. Geol.
figs. 2a-c; 3a-c; not figs.
Remarks.—Hedbergella amabilis seems to have been
derived from Hedbergella delrioensis (Carsey) . The writer
has observed numerous transitional the Ceno-
manian portion of the Eagle Ford group. H. amabilis is
distinguished from other species of Hedbergella by the more
clavate character of its chambers and the thinner, lower
forms in
282 PALAKONTOGRAPHICA AMERICANA (V, 37)
spired nature of its test as seen in peripheral view. Numer-
ous gradational forms exist between H. amabilis and
Clavihedbergella simplex (Morrow) . These are common in
the Cenomanian portion of the Eagle Ford group of Texas.
Range.—Rotalipora s.s. assemblage zone: R. cushmant
—greenhornensis assemblage zone to M. renzi assemblage
zone; (2?) G. bulloides assemblage zone, M. concavata sub-
zone.
Occurrence._In Mexico H. amabilis occurs in_ the
Cenomanian, Turonian, and Coniacian portions of the San
Felipe formation (cf. Text-figure 2). In Texas H. amabilis
occurs in the Cenomanian and Turonian portions of the
Eagle Ford group (Britton clay, Arcadia Park formation,
Lake Waco formation, South Bosque formation, and Chispa
Summit formation and in the Coniacian and Early San-
tonian portions of the Austin chalk (“Atco member’’) . It
should be noted that the Santonian occurrences of this
species are in areas (e.g., Dallas, Waco; cf. Text-figure 2)
where basal Austin (“Atco”) strata assignable to the M.
concavata subzone rest with marked disconformity on
Eagle Ford strata (South Bosque and Arcadia Park) assign-
able to the M. helvetica assemblage zone. Elsewhere in
Texas and in Mexico, where intervening Coniacian strata
assignable to the M. renzi assemblage zone are present, H.
amabilis appears to be absent in Santonian strata assign-
able to the M. concavata subzone.
H. amabilis was described by Loeblich and ‘Tappan
(1961, p. 274) from the Britton clay (Eagle Ford group).
They also noted it in the Cenomanian deposits of the Blake
Plateau and in the Atkinson formation of Georgia.
The writer has observed this species in Cenomanian
samples from both Puerto Rico and Trinidad. One of the
forms figured by Ayala, (1962) (see synonomy) from the
Cenomanian of Cuba as C. simplex is referrable to H. ama-
bilis, Likewise, the specmen figured as C. simplex by Todd
and Low (1964, pp. 403, 404, jl. 1, fig. la-c) from the Ceno-
manian of the north slope of the Puerto Rican trench is
referrable to H. amabilis.
Renz, Luterbacher, and Schneider (1963, p. 1084)
noted H. amabilis in the Cenomanian of the Neuenburger
Jura of western Switzerland.
Hedbergella brittonensis Loeblich and Tappan
Plate 52, figures 9-12
1961. Hedbergella brittonensis Loeblich and ‘Tappan, Micropaleont.,
vol. 7, No. 3, pp. 274, 275, pl. 4, figs. 1-8.
1962. Hedbergella brittonensis Loeblich and Tappan, Ayala, Soc. Geol.
Mex., Bol., vol. 25, No. 1, pp. 23, 24, pl. 3, figs. la-c; pl. 8, figs.
3a-b.
Remarks.—Hedbergella brittonensis Loeblich and ‘Tap-
pan is characterized by its high-spired and rather papillose
test. It seems suspiciously similar to Hedbergella ports-
downensis (Williams—Mitchell, 1948) and may be a junior
synonym of this latter species.
Hedbergella brittonensis appears to have been derived
from a Hedbergella delrioensis stock. Numerous transitional
forms have been observed in the Lake Waco formation and
the Britton clay (Eagle Ford group of ‘Vexas) .
Range.—Rotalipora s.s. assemblage zone, R. cushmani
—greenhornensis subzone—M,. renzi assemblage zone.
Occurrence.—In the present study H. brittonensis has
been observed in the Cenomanian and Turonian portions
of the San Felipe formation of Mexico (cf. Text-figure 2).
H. brittonensis occurs at numerous localities throughout
the Cenomanian and Turonian portions of the Eagle Ford
group of ‘Texas (Chispa Summit formation, Lake Waco
formation, South Bosque formation, Britton clay, and Ar-
cadia Park formation). It also has been observed in the
Coniacian portion of the Austin chalk in Kinney County,
Texas (Rio Grande area, TX 36; see Appendix) .
Hedbergella delrioensis (Carsey)
Plate 48, figures 1,2, 3-5
1926. Globigerina cretacea d'Orbigny var. delrioensis Carsey, Univ.
Texas Bull. 2612, p. 43, no figures.
1937. Globigerina infracretacea Glaessner, Lab. Moscow Univ., Pal.
Publ., Studies Micropaleont., vol. 1, No. 1, pp. 28, 47, pl. 1.
1940. Globigerina cretacea @'Orbigny, Tappan, Jour. Paleont., vol. 14,
No. 2, p. 12], pl. 19; fig. 11.
1943. Globigerina cretacea d’Orbigny, Tappan, Jour. Paleont., vol. 17,
No. 5, p. 512, pl. 82, figs. 16, 17.
1952. Globigerina gautierensis Bronnimann, Bull. Amer. Paleont.,
vol. 35, No. 140, p. 11, pl. 1, figs. 1-3 text-figure 2: a-m.
1954. Globigerina delrioensis Carsey, Frizzell, Univ. Texas, Bur. Econ.
Geol., Rept. Invest. 22, p. 127, pl. 20, fig. 1.
1959. Praeglobotruncana gauteriensis (Bronnimann), Bolli, Bull. Amer.
Paleont., vol. 39, No. 179, p. 265, pl. 21, figs. 3-6.
1959. Praeglobotruncana (Hedbergella) delrioensis (Carsey), Banner
and Blow, Paleontology, vol. 2, pt. 1, p. 8.
1960. Praeglobotruncana gautierensis (Bronnimann), Jones, Contr.
Cushman Found. Foram. Res., vol. 11, pt. 3, p. 102, pl. 15, figs.
la-c, 2a-c, 23, 24, 5, 26, 7a-c, 8, Ya-c; text-fig. 1.
1962. Not Praeglobotruncana gautierensis (Bronnimann), Pessagno,
Micropaleont., vol. 8, No. 3, p. 358, pl. 6, fig. 4.
1963. Hedbergella delrioensis (Carsey), Renz, Luterbacher, and
Schneider, Eclogae Geol. Helv., vol. 56, No. 2, p. 1083, pl. 9,
figs. 5a-c.
1964. ? Hedbergella delrioensis (Carsey), Todd and Low, Deep-Sea
Research, vol. 11, p. 402, pl. 1, figs. 2a-c.
Description.—Test coiled in a low trochospiral coil with
five inflated, spherical, lobulate chambers in last whorl;
consisting of about two whorls. Chambers of first whorl and
first two or three chambers of last whorl often coarsely
rugose; last three chambers smooth. Spiral side of test rela-
tively low with earlier whorl either depressed or flush with
final whorl. Umbilical side deeply umbilicate; umbilicus
small. Sutures on both spiral and umbilical sides radial, de-
GULF CREVACEOUS FORAMINIFERA: PESSAGNO 283
pressed, straight to slightly curved. Outer wall radial hya-
line perforate; rugosites ultragranular hyaline imperforate;
septal walls and portici microgranular hyaline, perforate.
Primary aperture interiomarginal, extraumbilical-umbili-
cal; well-developed portici flank apertures opening into
umbilicus.
Remarks.—Carsey (1926, p. 43) originally described
this species from the Grayson formation (Del Rio clay)
of Travis County, Texas, but failed to figure it and desig-
nate the depository of the type specimens. The type speci-
mens are assumedly deposited in the Carsey Collection at
the University of Texas. However, if the Carsey’s types
cannot be located, a neotype will have to be erected for
this important species.
Hedbergella delrioensis (Carsey) differs from Hed-
bergella planispira (Tappan) (1) by the more deeply um-
bilicate and thicker nature of its test; (2) by the more
rapid increase in the size of its chambers; (3) by the smaller
number of chambers in the last whorl (four to six as op-
posed to six to eight); (4) by its less curved sutures; and
(5) by the more strongly rugose character of its earlier
chambers.
The writer has examined the holotype of Globigerina
gautierensis Bronnimann at the U.S. National Museum and
has found it to be a junior synonym of H. delrioensis (Car-
sey). Globigerina infracretacea Glaessner (1937, p. 47) is
also regarded as a junior synonym of H. delrioensis. The
smaller size of Glaessner’s form is regarded as no criterion
to validate its separate identity. In addition, according to
the Catalogue of Foraminifera (Ellis and Messina) G.
infracretacea was described from strata of Albian age. This
occurrence is not inconsistent with the known range of H.
delrioensis.
Range.—H. washitensis assemblage zone to M. renz
assemblage zone; (?) to G. fornicata—stuartiformis assem-
blage zone, A. blow: subzone (D. multicostata zonule) .
Occurrence —During the course of this study H. del-
rioensis (Carsey) has been observed in the San Felipe for-
mation and Méndez shale of Mexico and in the Grayson
formation (=Del Rio clay), the Eagle Ford group, and the
Austin chalk of Texas. H. delrioensis occurs in the Ceno-
manian of Trinidad and is known from the Cretaceous of
Europe.
Hedbergella (?) homedelensis Olsson
1964. Hedbergella homedelensis Olsson, Micropaleont., vol. 10, No. 2.
pp. 160, 161, pl. 1, figs. 1, 2.
1964. Hedbergella planispira (Tappan), Olsson, Micropaleont., vol.
10, No. 2, pp. 161, 162, pl. 1, figs. 4, 5.
Remarks.—As noted by Olsson (1964, pp. 161, 162),
this species seems to be closely related to H. monmouthensis
(Olsson). It differs from the latter species by possessing a
larger and shallower umbilicus, by possessing a slitlike pri-
mary aperture, and by possessing subspherical, more com-
pressed chambers in its final whorl.
It is likely that tegilla will be found on well-preserved
specimens of H. (?) homedelensis and it will eventually
have to be placed in Globotruncanella. It is probable that
no true Hedbergella exist in Maestrichtian or Late Cam-
panian strata.
Range.—G. fornicata—stuartiformis assemblage zone,
R. subcircumnodifer subzone. Olsson (1964, p. 158) in-
ferred that H. (?) homedelensis occurred in a New Jersey
faunal assemblage which would correlate herein with the
writer's G. fornicata—stuartiformis assemblage zone, R. swb-
circumnodifer subzone.
Occurrence—In the course of this study H. (?) home-
delensis has been recognized in the Méndez shale (MX 14,
see Appendix) of Mexico; in the Upson clay and Escondido
formation of Texas (TX 60 and TX 75, see Appendix) ;
and in the Saratoga chalk (AR 17, see Appendix) of south-
western Arkansas.
Hedbergella (?) mattsoni (Pessagno)
Plate 50, figures 7-8
1960. Praeglobotruncana mattsoni Pessagno, Micropaleont., vol. 6,
No. 1, pp. 98, 99, pl. 2, figs. 1-3, 6-8.
Remarks.—The large portici figured by Pessagno (1960,
pl. 2, figs. 6-8), though somewhat fragmentary, may indi-
cate that H. mattsoni should be included under Globotrun-
canella.
Range.—G._ fornicata—stuartiformis assemblage zone,
G. elevata subzone (G. calcarata zonule) to R. swhcircum-
nodifer subzone (R. subpennyi zonule) .
Occurrence—In Texas H. (?) mattsoni has been ob-
served in the Upson clay of Maverick County and “Upper
‘Taylor marl” of Limestone County. It was originally des-
cribed from the Rio Yauco formation of Puerto Rico.
Hedbergella planispira (Tappan)
Plate 51, figure 1; Plate 53, figures 1,2, 3,4
1940. Globigerina planispira Tappan, Jour. Paleont., vol. 14, No. 2,
p- 12, pl. 19, fig. 12:
1943. Globigerina planispira Tappan, Tappan, Jour. Paleont., vol.
175 NO 9; (ps 513; pli 835 fig.)
1948. ? Globigerina almadenensis Cushman and Todd, Contr. Cush-
man Lab. Foram. Res., vol. 24, pt. 4, p. 95, pl. 16, figs. 18, 19.
1949. Globigerina globigerinelloides Subbotina, Microfauna Oilfields
USSR, vol. 2, p. 32, pl. 2, figs. 11-16.
1953. Globigerina globigerinelloides Subbotina, Subbotina, Trudy,
Vses. Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76,
pl. 1, figs. 11, 12.
1954. Globorotalia (?) youngi Fox, U.S. Geol. Sur., Prof. Paper, No.
254-E, p. 119, pl. 26, figs. 15-18.
284 PALAEBONTOGRAPHICA AMERICANA (V, 37)
1956. Hedbergina seminolensis (Harlton), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2. p. 529, pl. 20, figs. 4-6.
1957. Praeglobotruncana planispira (Tappan) , Bolli, et al., U.S. Nat.
Mus., Bull., No. 215, p. 40, pl. 9, fig. 3.
1959. Praeglobotruncana planispira (Tappan), Bolli, Bull. Amer.
Paleont., vol. 39, No. 179, p. 267, pl. 22, figs. 3, 4.
1959. Praeglobotruncana modesta Bolli, Bull. Amer. Paleont., vol. 39,
No. 179, p. 267, pl. 22, fig. 2.
1961. Hedbergella planispira (Tappan) , Loeblich and ‘Tappan, Micro-
paleont., vol. 7, No. 3, pp. 276, 277, pl. 5, figs. 4-11.
1961. Hedbergella trocoidea (Gandolfi) , Loeblich and ‘Tappan, Micro-
Onn
paleont., vol. 7, No. 3, pp. 277, 278, pl. 5, figs. 1, 2.
1962. Hedbergella trocoidea (Gandolfi), Ayala, Soc. Geol. Mexicana,
Bol., vol. 25, No. 1, pp. 24, 25, pl. 3, figs. 3a-c; pl. 9, figs. la, b.
1963. 2? Hedbergella trocoidea (Gandolfi), Bronnimann and Rigassi,
Eclogae Geol. Helyv., vol. 56, No. 1, pl. 14, figs. la-c.
1964. Hedbergella trocoidea (Gandolfi), — Loeblich and ‘Tappan,
Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2, p. C659,
fig. 527: la-c.
1964. Not. Hedbergella planispira (Tappan), Olsson, Micropaleont.,
vol. 10, No. 2, pp. 161, 162, pl. 1, figs. 4, 5.
Remarks.—Hedbergella planispira (Tappan) is similar
to Hedbergella trocoidea (Gandolfi). It differs from H.
trocoidea (1) by showing a more rapid increase in chamber
size; (2) by having two as opposed to three or four well-
developed whorls; and (3) by having a more lobulate peri-
phery. Variations in size and amount of ornamentation are
not regarded as sound criteria for the separation of these
two species. Hedbergella planispira differs from the remain-
ing species of Hedbergella by having a low trochospiral,
nearly planispiral test.
The specimens figured by Loeblich and Tappan (1961,
1964; see synonymy) as H. trocoidea do not resemble the
lectotype (pl. 2, figs. la-c of Gandolfi, 1942) for this species
selected by Bronnimann and Brown (1958, p. 16) as they
show a more rapid increase in chamber size per whorl;
have fewer whorls; and have a more lobulate periphery.
The holotype of H. planispira (Tappan) was ex-
amined at the U.S. National Museum during the course of
this study.
Range.—H. washitensis assemblage zone to M. renzi
assemblage zone.
Occurrence.—In Texas the writer has observed H. plan-
ispira in the Grayson formation (Del Rio clay), the
Eagle Ford group, and in the Coniacian portion of the
Austin chalk. In Mexico it occurs in the San Felipe forma-
tion at Boca Canyon somewhat south of Monterrey and in
the upper part of the Tamaulipas limestone in Peregrina
Canyon (see Text-figure 2) .
Loeblich and Vappan (1961, pp. 276, 277) noted this
species in the Grayson formation and the Eagle Ford group
of Texas; in the Greenhorn limestone of South Dakota,
Wyoming, and Kansas; in Cenomanian samples from a sub-
marine core from the Blake Plateau; in the Cenomanian of
Germany; and in the Albian and Cenomanian of the
U.S.S.R. and Trinidad. H. planispira has been recorded by
Ayala (1962, pp. 24, 25) as H. trocoidea from the Ceno-
manian of Cuba.
Hedbergella washitensis (Carsey)
Plate 49, figure 1
1926. Globigerina washitensis Carsey. Univ. Texas Bull. 2612, p. 44,
pl. 7, fig. 10; pl. 8, fig. 2.
1931. Globigerina washitensis Carsey, Plummer, Univ. Texas Bull.
3101, p. 193, pl. 13, figs. 12a, b (Neotype of Plummer) .
1940. Globigerina washitensis Carsey, Tappan, Jour. Paleont., vol. 14,
No. 2, p. 122, pl. 19, fig. 13.
1943. Globigerina washitensis Carsey, Tappan, Jour. Paleont., vol. 17,
No. 5, p. 513, pl. 83, figs. la-c, 2.
1944. Globigerina washitensis Carsey, Lozo, Amer, Midland Nat., vol.
SI NO 3p. 003,, pln dS, tle ke
1949. Globigerina washitensis Carsey, Loeblich and Tappan, Jour.
Paleont., vol. 23, No. 3, p. 265, pl. 51, fig. 4.
1954. Globigerina washitensis Carsey, Frizzell, Univ. Texas Bur. Econ.
Geol., Rept. Invest. 22, p. 127, pl. 20, figs. 9a-c.
1956. Globigerina washitensis Carsey, Bolli, Jour. Paleont., vol. 30, No.
2, p. 293, pl. 39; figs. 2, 3, text-fig. 5 (lla, b).
1959. Globigerina washitensis Carsey, Bolli, Bull. Amer. Paleont., vol.
39) Nos 179) py 271, spl., 23; figs: (6,7:
1961. Hedbergella washitensis (Carsey), Loeblich and Tappan, Micro-
paleont., vol. 7, No. 3, p. 278, pl. 4, figs. 9, 10a-c, 1la-c.
1962. Hedbergella washitensis (Carsey), Ayala, Soc. Geol. Mexicana,
Ayala, No. 1, p. 22, pl. 3, figs. la-c.
Remarks.—This species is distinct from other species of
Hedbergella by its cancellate, honeycomb-like ornamenta-
tion. Its assignment to Hedbergella herein and by Loe-
blich and Tappan (1961, p. 278) is still a matter of dispute
because of the umbilical to only slightly extraumbilical
position of its primary aperture. In addition it has not
been definitely established whether H. washitensis possesses
portici as do all true species of Hedbergella. No exception-
ally well-preserved specimens of this species have been ob-
served during the course of this study. Hence, it has been
impossible for the writer to determine whether or not H.
washitensis possesses portici.
As Carsey’s type specimens were apparently lost, Plum-
mer (1931, p. 193, pl. 13, figs. la-b) erected a “neoholotype”
(=neotype) from the type locality of G. washitensis Carsey
(TYPE 5 herein, see Appendix) . Although Plummer’s term
“neoholotype” is not according to the modern International
Code of Zoological Nomenclature, she used the term in the
same sense that workers today use the term neotype. Fur-
thermore, her erection of a
accordance with Article 75 of the International Code of
Zoological Nomenclature (1961, pp. 81-85). The writer has
had the opportunity to examine Plummer’s neotype (No,
‘neoholotype” (—neotype) is in
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 285
20633) at the Paleontological Research Institution, Ithaca,
New York.
Range.—H. washitensis assemblage zone to Rotalipora
s.s. assemblage zone. This species has never been observed
in numerous samples from Texas and Mexico assignable to
the R. cushmani—greenhornensis subzone.
Occurrence.—In the course of this study H. washitensis
(Carsey) was observed in Texas in the Mainstreet lime-
stone, the Grayson formation (Del Rio clay), and in the
Buda limestone. This species is common to abundant in the
Grayson formation in the Rio Grande area, the Austin area,
the Waco area, and in the Dallas area. It has only been ob-
served in the Mainstreet at Waco and in the Buda at Austin.
In addition to Texas occurrences Loeblich and Tappan
(1961, p. 278) noted H. washitensis in the Albian and Ceno-
manian strata of Oklahoma, Minnesota, Trinidad, Algeria,
and in core samples from the submarine Blake Plateau
north of the Bahama Islands. Ayala (1962, p. 22) described
and figured it from the Cenomanian of Cuba.
Genus CLAVIHEDBERGELLA Banner and Blow, 1959
Type species.—Hastigerinella swbceretacea
1943.
Remarks—The diagnosis of Loeblich and Tappan
(1961, pp. 278, 279; 1964, p. C659) is followed herein.
Range.—Aptian to Coniacian.
Occurrence.—Cretaceous; world-wide.
‘Tappan,
Clavihedbergella moremani (Cushman)
Plate 53, figure 5; Plate 55, figures 1, 2
1931. Hastigerinella moremani Cushman, Contr. Cushman Lab. Vor-
am. Res., vol. 7, p. 86, pl. 11, fig. 1 (not figs. 2, 3).
1946. Hastigerinella moremani Cushman, Cushman (part), U.S. Geol.
Sur., Prof. Paper, No. 206, p. 147, pl. 61, fig. 1 (not figs. 2, 3).
1961. Clavihedbergella moremani (Cushman), Loeblich and Tappan,
Micropaleont., vol. 7, No. 3, p. 279, pl. 5, figs. 12-16.
Remarks.—Clavihedbergella moremani (Cushman) dif-
fers from Clavihedbergella simplex (Morrow) by possessing
more clavate chambers which often have bulbous termina-
tions.
The holotype (Cushman Collection, USNM) of Clawi-
hedbergella moremani has been refigured herein. The
paratypes figured by Cushman (1931, 1946) are referrable
to Clavihedbergella simplex (Morrow) as noted by Loe-
blich and Tappan (1961, p. 279).
Range.—Rotalipora s.s. assemblage zone, R. cushmani
—grecnhornensis subzone to M. helvetica assemblage zone,
W. archaeocretacea subzone.
Occurrence.—In this study C. moremani has been re-
corded only from the Eagle Ford group (Britton clay of
Dallas County and the Turonian portion Boquillas forma-
tion, Eagle Ford group) near the Kinney—Val Verde
County line (TX 30, see Appendix) .
Loeblich and Tappan (1961, p. 279) noted C. more-
mani at Britton clay localities and in the Atkinson forma-
tion of Echols County, Georgia.
Clavihedbergella simplex (Morrow)
Plate 52, figures 1, 2
1931. Hastigerinella moremani Cushman, Contr. Cushman Lab. For-
am. Res., vol. 7, p. 86, pl. 11, figs. 2, 3 (not fig. 1).
1934. Hastigerinella simplex Morrow, Jour. Paleont., vol. 8, No. 2, p.
198, pl. 30, fig. 6.
1937. Hastigerinella simplex Morrow, Loetterle, Nebraska Geol. Sur.,
2nd ser., Bull. 12, p. 46, pl. 7, fig. 5.
1946. Hastigerinella simplex Morrow, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 148, pl. 61, figure 10.
1946. Hastigerinella | moremani Cushman, Cushman (part), U.S.
Geol. Sur., Prof. Paper, No. 206, p. 147, pl. 61, figs. 2, 3, not
figure 1.
1954. Hastigerinella simplicissima Magné and Sigal in Cheylan, Magné,
Sigal, and Grekoff, Soc. Géol. France, Bull., sér. 6, vol. 3,
(1953) p. 487, pl. 14, figs. Ia-c.
1956. Schackoina sp. cf. S. gandolfi Reichel, Kiipper, Contr. Cushman
Found. Foram. Res., vol. 7, pt. 2, p. 44, pl. 8, figs. da-c.
1961. Clavihedbergella simplex (Morrow), Loeblich and Tappan
part), Micropaleont., vol. 7, No. 3, pp. 279, 280, pl. 3, figs. 12a-
14b; not lla-c.
1962. Clavihedbergella simplex (Morrow), Ayala, Soc. Geol. Mex.,
Bol., vol. 25, pp. 25, 26, pl. 4, figs. la-c, not figs. 2a-c, 3a-c; pl.
5, not figs. la-c.
1964. Not Clavihedbergella simplex (Morrow), Todd and Low, Deep-
Sea Research, vol. 11, pp. 403, 404, pl. 1, figs. la-c.
Remarks.—Clavihedbergella simplex (Morrow) differs
from Clavihedbergella moremani (Cushman) by possessing
stouter, less clavate chambers which lack bulbous termina-
tions. Numerous transitional forms occur in Eagle Ford
samples between Hedbergella amabilis Loeblich and Tap-
pan and Clavihedbergella simplex (Morrow). C. simplex
is believed to have evolved from a H. amabilis ancestor.
Most of the forms figured by Ayala (1962, see synon-
omy) and the form figured by Todd and Low (1964, pl. 1,
figs. la-c) as C. simplex seem more referrable to H. amabilis
Loeblich and Tappan although they could be regarded as
transitional forms between these two taxa.
Range.—Rotalipora s.s. assemblage zone, R. cushmani—
ereenhornensis subzone to M. renzi assemblage zone.
Occurrence.—C, simplex has been observed in the
Cenomanian and Turonian portions of the Eagle Ford
group throughout Texas from the Rio Grande area to the
Dallas area (see Text-figure 2). It also occurs in the Con-
iacian portion of the Austin chalk in Kinney County,
Texas (IX 36, see Appendix). In Kinney, Val Verde and
Terrell Counties the Austin rests conformably on the Eagle
Ford with no evidence of an erosional break (cf. Text-figure
2). In Mexico C. simplex occurs in the Upper Cenomanian
and Turonian portions of the San Felipe formation as ex-
PYRO PALAEKONTOGRAPHICA AMERICANA (V, 37)
posed at Boca Canyon south of Monterrey and at Mamu-
lique Pass to the north of Monterrey. Loeblich and ‘Tappan
(1961, pp. 279-280) noted this species in the Eagle Ford
group of Texas, the Greenhorn limestone of Kansas, the
Niobrara chalk of Nebraska, the Austin chalk of Texas, and
the “Antelope shale” of California. It is also known from
the Cenomanian of Cuba (cf. Ayala, 1961) and the Ceno-
manian of Tunisia.
Genus PRAEGLOBOTRUNCANA Bermudez, 1952
Type species—Globorotalia delrioensis Plummer, 1931.
Remarks.—The diagnosis presented by Loeblich and
Tappan (1961a, p. 280; 1964, p. C659) is followed herein.
Range.—Albian—Cenomanian., Lower Turonian (?) .
Occurrence.—Cretaceous; world-wide.
Praeglobotruncana bronnimanni Pessagno, n. sp.
Plate 49, figures 6-11
1964. Praeglobotruncana delrioensis (Plummer), Todd and Low, Deep-
Sea Research, vol. 11, p. 404, pl. 2, figs. da-c.
Description.—Test trochospiral, relatively biconvex, car-
inate with five to seven angular rhomboid chambers in last
whorl. Sutures on spiral side curved, slightly raised; sutures
on umbilical side straight, radial, depressed. Umbilicus
small and deep, bordered by well-developed shoulder. Pri-
mary aperture highly arched, extraumbilical-umbilical in
position. Outer wall except for keel radial hyaline perfor-
ate; keel radial hyaline imperforate; septal wall microgranu-
lar hyaline perforate.
Remarks.—Praecglobotruncana bronnimanni Pessagno,
n. sp. differs from Praeglobotruncana stephani (Gandolfi)
and Praeglobotruncana delrioensis (Plummer) (1) by the
more angular rhomboid shape of its chambers; (2) by pos-
sessing a pronounced peripheral keel; and (3) by having a
well-developed umbilical shoulder.
This species is similar and probably closely related to
Rotalipora evoluta Sigal, but lacks sutural supplementary
apertures on the umbilical side of the test. P. bronnimanni
most likely represents the forerunner of R. evoluta. In the
writer’s opinion it seems likely that Rotalipora evolved
from a praeglobotruncanid stock through the acquisition of
sutural supplementary apertures whereas Ticinella evolved
from a hedbergellid stock through the acquisition of sutural
supplementary apertures.
Praeglobotruncana bronnimanni Pessagno, n. sp. is
named after Dr. Paul Bronnimann in recognition of his
great contributions to the micropaleontology and to the
geology of the West Indies.
The holotype and figured paratypes of Praeglobotrun-
cana bronnimanni Pessagno, n. sp. will be deposited in the
collections of the U.S. National Museum, Washington, D.C,
Type locality.—The holotype of P. bronnimanni Pes-
sagno, n. sp. is from the Grayson formation (Del Rio
clay) as exposed on the west bank of Shoal Creek, just south
of the 34th Street Bridge, Austin, Travis County, ‘Texas.
Type 5-B, the sample from which the holotype was ex-
tracted, occurs in the Grayson 25 feet above the level of
Shoal Creek and about 20 feet below the contact between
the Grayson formation and the Buda limestone. ‘The fig-
ured paratypes are from localities TX 195 and ‘TX 19 in the
Grayson formation. TX 195 occurs in the Grayson forma-
tion 16.5 feet below the contact with the Pepper shale along
a tributary of the South Bosque River, approximately 0.9
miles east of Farm Road 2416 and 2.1 miles northeast of
Spring Valley, McLennan County, Texas. TX 19 occurs in
the Grayson formation 17.5 feet above the Grayson—George-
town contact as exposed on Evans Creek 0.8 miles west of
the bridge crossing of U.S. Route 90 over Evans Creek, Val
Verde County, Texas. The U.S. Route 90 bridge over Evans
Creek is situated about 2.8 miles from the U.S. Route 90
(Devil's River Canyon) bridge.
Range.—Rotalipora s.s. assemblage zone, R. evoluta
subzone.
Occurrence.—In the course of this study P. bronni-
manni has been found only in the Grayson formation. At
TYPE 5B P. bronnimanni occurs in an early Cenomanian
assemblage containing Rotalipora evoluta Sigal. TX 195,
a sample in which it also occurs, is situated 10 feet above
TX 194 which also contains Rotalipora cvoluta Sigal. R.
evoluta has also been found at TX 19 in the Evans Creek
section of the Grayson.
Praeglobotruncana delrioensis (Plummer)
Plate 52, figures 3-5; Plate 100, figure 7
1931. Globorotalia delrioensis Plummer, Uniy. Texas Bull. 3101, p.
199, pl. 13, figs. 2a-c.
1946. Globorotalia marginaculeata Loeblich and Tappan, Jour. Pal-
eont., vol. 20, No. 3, p. 257, pl. 37, figs. 19-21, text-fig. 4a.
1952. Praeglobotruncana delrioensis (Plummer), Bermudez, Venezuela,
Minist. Minas e Hidrocarb., Bol. Geol., vol. 2, No. 4, p. 52, pl.
Us sats IG
1954. Globorotalia delrioensis Plummer, Frizzel, Univ. Texas, Bur.
Econ. Geol., Rept. Invest. 22, p. 129, pl. 20, fig. 27.
1956. Praeglobotruncana delrioensis (Plummer). Bronnimann and
Brown (part), Geol. Eclogae Helv., vol. 48, No. 2, p. 53, pl. 21,
figs. 8-10; pl. 24, fig. 17, 716; text-figures 9, 13a, b, d; ?l5cf;
not 16c,d,e. :
1957. Praeglobotruncana delrioensis (Plummer) , Bolli, et al., U.S. Nat.
Mus. Bull., No. 215, p. 39, pl. 39, fig. 1.
1959. 2 Praeglobotruncana (Praeglobotruncana) sp. cf. stephani
(Gandolfi), Banner and Blow, Paleontology, vol. 2, pt. 1, pl. 3,
fig. 4.
1961. Praeglobotruncana delrioensis (Plummer), Loeblich and Tap-
pan, Micropaleont., vol. 7, No. 3, pp. 280-284, pl. 6, figs. 9-12.
1964. Not Praeglobotruncana delrioensis (Plummer), Todd and Low,
Deep-Sea Research, vol. 11, p. 404, pl. 2, fig. 4.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 287
Remarks.—As noted by Loeblich and Tappan (1961, p.
282), P. delrioensis (Plummer) has been confused by a
number of workers with P. stephani (Gandolfi) . P. delrio-
ensis differs from P. stephani (1) by being more biconvex;
(2) by having a coarsely spinose periphery; and (3) by
having compressed to subglobular chambers. As a rule, P.
delrioensis is smaller in size than P. stephani and is restrict-
ed to strata of Albian to Early Cenomanian age. P. stephani
occurs in strata of Late Cenomanian and (?) Turonian age.
The sectioned specimen of P. delrioensis from the Gray-
son formation (Plate 100, fig: 7) shows an imperforate
peripheral band developed in the posterior portion of the
final whorl and in both the posterior and anterior positions
of the previous whorl.
A hypotype of P. delrioensis (Plummer) (No. 20634)
was examined in that part of the Plummer Collection at the
Paleontological Research Institution, Ithaca, New York.
Range.—H. washitensis assemblage zone to Rotalipora
s.s. assemblage zone, R. evoluta subzone.
Occurrence.—Praeglobotruncana delrioensis was noted
in this study in the Grayson formation in Val Verde, ‘Travis,
McLennan, and Denton Counties in Texas. Loeblich and
Tappan (1961, pp. 280-284) noted that it occurs in strata
of equivalent age in Trinidad, Switzerland, and in subma-
rine cores from the Blake Plateau north of the Bahamas.
Praeglobotruncana stephani (Gandolfi)
Plate 50, figures 9-11
1942. Globotruncana stephani Gandolfi, Riv. Ital. Pal., ann. 48, mem.
4, p. 130, pl. 3, figs. 4, 5; pl. 4, figs. 36, 37, 41-45; pl. 6, figs. 4,
OplROeies Dy OM plals tip. s ple. fig.
1942. Globotruncana appenninica var. beta Gandolfi, Riv. Ital. Pal.,
ann. 48, mem. 4, p. 119, text-fig. 41 (2a-b).
1945. Globotruncana stephani Gandolfi, Bolli (part), Eclogae Geol.
Helv., vol. 37, No. 2, p. 224, text-fig. 1 (nos. 3, 4); ? pl. 9, fig. 2.
1948. Globorotalia californica Cushman and Todd, Contr. Cushman
Lab. Foram. Res., vol. 24, p. 96, pl. 16, figs. 22, 23.
1950. Globotruncana (Globotruncana) stephani Gandolfi, Reichel,
Eclogae Geol. Helv., vol. 42, No. 2, p. 609, pl. 16, fig. 6; pl. 17,
fig. 6.
1950. Globotruncana stephani Gandolfi var. turbinata Reichel, Ec-
logae Geol. Helv., vol. 42, No. 2, p. 609.
1950. Globotruncana stephani Gandolfi var. turbinata Reichel, Mor-
nod, Eclogae, Geol. Helvy., vol. 42, No. 2, p. 589, text-fig.
17 (1-3); pl. 15, figs. 9a-r, 18-20; not 10-17.
1953. Rotundina stephani (Gandolfi), Subbotina, Trudy, Vses. Neft.
Naukno. Issled. Geol. Razved. Instit., n. ser., No. 76, p. 165,
ple tpson/; plas, tips. I) 2:
1954. Globotruncana stephani Gandolfi var. turbinata Reichel, Hagn
and Zeil, Eclogae Geol. Helv., vol. 47, No. 1, p. 34, pl. 2, fig. 2:
pl. 5, figs. 3, 4.
1954. Globotruncana stephani Gandolfi, Ayala, Assoc. Mex. Geol.
Petrol., Bol., vol. 6, Nos. 11, 12, p. 412, pl. 11, fig. 2.
1954. Globotruncana stephani Gandolfi var. turbinata Reichel, Ayala,
Assoc. Mex. Geol. Petrol., Bol., vol. 6, Nos. Il, 12, p. 412, pl. 11,
fig. 3
1955. Globotruncana (Rotundaina) aumalensis (Sigal), Kiipper, Contr.
Cushman Found. Foram. Res., vol. 6, pt. 3, p. 116, pl. 18, fig. 5.
1955. Globotruncana (Rotundaina) stephani Gandolfi, Kiipper,
Contr. Cushman Found. Foram. Res., vol. 6, pt. 3, p. 116, pl. 18,
fig. 6.
1956. Globotruncana (Praeglobotruncana) stephani Gandolfi —tur-
binata Reichel, Kipper, Contr. Cushman Found. Foram. Res.,
vol. 7, pt. 2, p. 43, pl. 8, figs. la-c.
1956. Globotruncana (Praeglobotruncana) renzi (Thalmann and
Gandolfi) subsp. primitiva Kiipper, Contr. Cushman Found.
Foram. Res., vol. 7, pt. 2, p. 43, pl. 8, figs. 2a-c.
1956. Praeglobotruncana delrioensis var. turbinata (Reichel) , Bronni-
mann and Brown, Eclogae Geol. Hely., vol. 48, No. 2, p. 532,
text-figs. 16c-e.
1957. Globotruncana (Globotruncana?) stephani turbinata Reichel,
Gandolfi, Contr. Cushman Found. Foram. Res., vol. 8, pt. 2, p.
62, pl. 9, fig. 4.
1957. Praeglobotruncana stephani (Gandolfi), Bolli, et al., U.S. Nat.
Mus., Bull., No. 215, p. 39, pl. 9, fig. 2.
1959. Praeglobotruncana stephani (Gandolfi), Orlov, et al., Osnovy
Paleontologi, text-fig. 687 A-C.
1959. Praeglobotruncana (Praeglobotruncana) stephani, Banner and
Blow, Paleontology, vol. 2, pt. 1, p. 3, text-fig. la.
1960. Praeglobotruncana stephani (Gandolfi), Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 794, p. 6, figs 2a-c
1960. Praeglobotruncana stephani var. turbinata (Reichel), Klaus,
Eclogae Geol. Helv., vol. 52, No. 2, p. 795, pl. 6, figs. 3a-c.
1961. Praeglobotruncana stephani (Gandolfi) , Loeblich and ‘Tappan,
Micropaleont., vol. 7, No. 3, pp. 284-290, pl. 6, figs. 1-8.
1964. Praeglobotruncana stephani (Gandolfi), Loeblich and Tappan,
Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2, p. C659,
fig. 527; 3a-c.
Remarks.—Praeglobotruncana stephani (Gandolf) dif-
fers from Praeglobotruncana delrioensis (Plummer) : (1)
by being much more convex spirally; (2) by having rhom-
boidal chambers; and (3) by lacking a coarsely spinose
periphery.
‘The writer agrees with Loeblich and Tappan (1961, p.
286) that the larger, more spirally convex specimens fre-
quently referred to in the literature as P. stephani var.
turbinata (Reichel) should be regarded as adult or gerontic
individuals of P. Stephani. Both the smaller, less spirally
convex specimens (=P. stephani var. turbinata) have the
same geologic range. Thus, as noted by Loeblich and ‘Tap-
pan (vbid.), the retention of two names for these forms
serves no useful purpose geologically.
Range.—Rotalipora s.s. assemblage zone, R. cushmani—
ereenhornensis subzone. ? M. helvetica assemblage zone.
Occurrence.—In this study P. stephani has been ob-
served in the San Felipe formation of Mexico (MX 131, see
Appendix) and in the Eagle Ford group (Britton clay) of
Texas. Loeblich and Tappan (1961, p. 288) noted that P.
stephani occurs in the Cenomanian of Switzerland, Italy,
Russia, and Bavaria. They also noted that it occurs in the
Britton clay of Texas and in the “Antelope shale” and
“Franciscan series” of California.
Subfamily LOEBLICHELLINAE Pessagno, new subfamily
Type genus. —Loeblichella Pessagno, new genus.
Description.—Tests coiled in a low trochispire; primary
aperture extraumbilical—umbilical to spiroumbilical with
O88 PALAEONTOGRAPHICA AMERICANA (V, 37)
well-developed portici. Sutural supplementary apertures on
spiral side of test only.
Remarks.—Vhe Loeblichellinae differ from the Hed-
bergellinae by the possession of sutural supplementary aper-
tures and from the Rotaliporinae by the possession of su-
tural supplementary apertures on the spiral side of the test
only.
Occurrence.—Upper Cretaceous of West Indies and
North America.
LOEBLICHELLA Pessagno, new genus
Ty pe species —Praeglobotruncana hessi_ 5.8. Pessagno,
1962
Description.—Test low, trochospire without imperforate
peripheral band or carina. Primary aperture, slitlike, ex-
traumbilical—umbilical to spiroumbilical in position with
broad, well-developed portici extending into wide, shallow
umbilicus. Sutural supplementary apertures present on the
spiral side of test only. Outer wall, radial hyaline perforate;
septal wall microgranular hyaline, perforate; porticl micro-
eranular hyaline, perforate (?) .
Remarks.—Loeblichella differs from Hedbergella (1)
by possessing sutural supplementary apertures on the spiral
side of the test and (2) by having a primary aperture which
varies between extraumbilical and spiroumbilical in posi-
tion.
This genus is named for Helen ‘Vappan Loeblich in
honor of her numerous contributions to micropaleontology.
Range.—Rotalipora s.s. assemblage zone, R. cushmani—
greenhornensis subzone to G. contusa—stuartiformis assemb-
lage zone, G. ganssert subzone. There have been no recorded
occurrences of this genus in the A. mayaroensis subzone to
date although such occurrences are likely.
Loeblichella hessi (Pessagno)
Plate 48, figures 17-19; Plate 61, figures 6-8; 9-11;
Plate 100, figures 1-2
1962. Praeglobotruncana hessi hessi Pessagno, Micropaleont., vol. 8,
No. 3, pp. 358-360, pl. 5, figs. 8-12.
Description.—Test low, trochospirally coiled; spiral side
flattened except for convex projection of individual cham-
bers. Periphery lobulate, chambers increasing rapidly in
size; early chambers spherical; later chambers markedly
ovate in cross-section. Last whorl with five to six subtrape-
zoidal to trapezoidal chambers. Chambers coarsely rugose.
Sutures depressed, straight to slightly curved on both spiral
and umbilical sides. Aperture a slitlike opening, extraumbi-
lical to spiroumbilical in position; large wide portici extend
into broad, shallow umbilicus from apertural areas of each
chamber. Sutural supplementary apertures on spiral side of
test; difficult to see except on well-preserved specimens.
Outer wall radial hyaline perforate; septal wall microgranu-
lar hyaline perforate. Portici microgranular hyaline perfor-
ate (?).
Remarks.—L. hessi s.s. (Pessagno) differs from L. coar-
ctata (Bolli) by lacking an angled periphery.
Range.—Rotalipora s.s. assemblage zone, R. cushmani—
greenhornensis subzone to Globotruncana contusa—stuarti-
formis assemblage zone, G. gansseri subzone in so far as
known.
Occurrence.—In the present study L. hessi s.s. has been
observed in the Eagle Ford group (Britton, Arcadia Park,
Lake Waco, South Bosque formations), “Lower ‘Taylor
marl’, Pecan Gap chalk, “Upper Taylor marl”, and Corsi-
cana marl of Texas. It also has been observed in the
Brownstown marl of Arkansas and the San Felipe forma-
tion of Mexico. The writer has also seen L. hessi s.s. in a
faunal assemblage assignable to the G. fornicata—stuarti-
formis assemblage zone, G. elevata subzone, (G. calcarata
zonule) from the Campanian of Austria. L. hessi s.s. was
originally described from the Rio Yauco formation of
Puerto Rico.
Loeblichella coarctata (Bolli)
Plate 48, figures 14, 16, 20; Plate 61, figures 4, 5; Plate 62,
figures 1-3; 6-8; Plate 76, figures 7-9
1957. Praeglobotruncana coarctata Bolli, U.S. Nat. Mus. Bull, No. 215,
p. 55, pl. 12, figs. 2a-3c.
1962. Praeglobotruncana hessi compressiformis Pessagno, Micropaleont.
vol. 8, No. 3, p. 360, pl. 5, figs. 1-7.
Remarks.—L. coarctata (Bolli) differs from L. hessi s.s.
(Pessagno) by possessing an angled periphery. Sectioned
specimens do not show either an imperforate peripheral
band or a keel. These two species are intimately related
and transitional forms are common.
A comparison of the types (USNM) of P. hessi com-
pressiformis Pessango with those of L. coarctata (Boll) in-
dicates that P. hessi compressiformis is a junior synonym of
P. coarctata Bolli.
Range.—Rotalipora s.s. assemblage zone, R. cushmani—
greenhornensis subzone to G. contusa—stuartiformis as-
semblage zone, G. gansseri subzone.
Occurrence.—During the course of this study L. coar-
ctata (Bolli) has been observed in the Eagle Ford group
(Britton clay, Arcadia Park formation, Lake Waco forma-
tion, and South Bosque formation) ; “Lower ‘Taylor marl”;
“Upper Taylor marl”; and Corsicana marl of Texas. It has
also been observed in the Brownstown marl of southwestern
Arkansas and in the Turonian portion of the San Felipe
formation of Mexico.
L. coarctata was originally described by Bolli from
the Naparima Hill formation of Trinidad. It also occurs in
the Rio Yauco formation of Puerto Rico.
Subfamily ROTALIPORINAE Sigal, 1958
Type genus.—Rotalipora Brotzen, 1942
Remarks.—The diagnoses presented by Loeblich and
Tappan (1961a, p. 290; 1964, p. C659) are followed herein.
Range.—Albian—Cenomanian.
Occurrence.—World-wide.
«# | European
S| Stoges Text — Figure 10: Schematic Plot of Rotaliporid Size versus
S
2 Cretaceous Time
| 5 | Danian
a
2 = == ees ee eee]
c
=
=
2
7
Ff
5
=
c
S
=
5
a
i=
5
U
c
5
4 5
4 =
3 <
S 8
° a
gs
ry
Fe 5
ry o
a 8
a =
=) &
U
Turonion
Cenomanian
Lower Cretaceous
Increase in Size
% Peak in size corresponds to peak in evolationary development
Genus ROTALIPORA Brotzen, 1942
Type species —Rotalipora turonica
Rotalipora cushmani (Morrow) , 1934).
Remarks.—The diagnoses of Loeblich and ‘Tappan
(1961a, p. 296; 1964, pp. C659-661) are ac cepted herein.
Range.—Rotalipora assemblage zone.
North America, South
America, West Indies, Eurasia, Africa, and Australia.
3rotzen, 1942 (==
Occurrence.—Cenomanian of
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 989
Rotalipora appenninica (O. Renz)
Plate 50, figures 1, 2; 4-6; Plate 51, figures 10-12; Plate 98,
1936.
1942.
1942.
1945.
1948.
1950.
1950.
1950.
1950.
1951,
1952.
1953.
1954.
1954.
1954.
1955.
1957.
1957.
1959.
1960.
1961.
1961.
1962.
1964.
figure 13, Plate 101, figures 1, 2
Globotruncana appenninica O. Renz, Eclogae Geol. Helv., vol.
29, No. 1, pp. 20, 135, text-figs. 2, 7a; pl. 6, figs. 1-11; pl. 7, fig. 1;
pl. 8, fig. 4.
Globotruncana appenninica O. Renz, Gandolfi (part), Riv. Ital.
Pal., ann. 48, mem. 4, p. 116, text-figs. 43, 44; pl. 2, figs. 5, 6;
pl. 4, figs. B13, 14, figs. C24-27, E45, 46; pl. 5, figs. 5, 6 (part) ;
pl. 6, fig. 4 (part) ; pl. 9, figs. 3, 6, 7; pl. 12, figs. 3, 6; pl. 14, figs.
3, 4.
Globotruncana appenninica O. Renz forma typica Gandolfi,
Riv. Ital. Pal., Ann. 48, mem. 4, p. 116, text-fig 42 (Nos 2, 3); pl.
ZALES Ds Os plates:
Globotruncana appenninica O. Renz, Bolli, Ec logae Geol. Helv.,
vol. 37, No. 2, pp. 223, 224, pl. 9, fig. 1; text-fig. 1: 1, 2.
Globotruncana appenninica O. Renz, Cita, Riv. Ital. Pal., vol. 54,
Nox3 5 Pel sple Ss aioale
Not Globotruncana (Rotalipora) appenninica O. Renz var.
typica Gandolfi, Mornod, Eclogae Geol. Helv., vol. 42, No. 2, p.
582, text-fig. 9; 2a-c.
Globotruncana (Rotalipora) appenninica O. Renz, Mornod
(part) , Eclogae Geol. Helv., vol. 42, No. 2, pp. 578-582, text-fig.
3: 3a-c; not la-c, 2a-c; text-fig. 4: 73a-c; not 4a-c; text-fig. 5:
la-c; not pl. 15, figs. la-c.
Globotruncana (Thalmanninella) brotzeni Sigal, Mornod,
Eclogae Geol. Hely., vol. 42, No. 2, pp. 586, 587, text-fig. 9: la-c.
Globotruncana (Rotalipora) appenninica O. Renz, Reichel,
Eclogae Geol. Hely., vol. 42, No. 2, p. 604, pl. 16, fig. 4; pl. 17
fig. 4.
Not Globotruncana appenninica cf. alpha Gandolfi, Bolli, Jour.
Paleont., vol. 25, No. 2, p. 193, pl. 34, figs. 1-3.
Rotalipora appenninica (O. Renz), Sigal, 19th Congr. Géol. In-
ternat., Monogr. Rég., Alger, ser. 1, No. 26, p. 24, text-fig. 23.
Rotalipora appenninica (O. Renz), Subbotina (part), Trudy,
Vses. Neft. Naukno. Issled. Geol. Razved. Instit., n. ser., No. 76,
p- 159, pl. 1, figs. 5a-c; 6a-c; 7a-c; not 8a-c; pl. 2, figs. la-c; 2a-c.
Rotalipora appenninica (O. Renz) , Hagn and Zeil (part) , Eclo-
gae Geol. Helv., vol. 47, No. 1, pp. 22-23, not pl. 1, fig. 1; pls:
fies Sl 2seplred tig ie
? Rotalipora turonica Brotzen, Hagn and Zeil (part) , Eclogae
Geol. Helv., vol. 47, No. 1, pp. 27, 28, pl. 4, fig. 3; not pl. 1 fig.
4; not pl. 1, fig. 5a-c.
Rotalipora appenninica (O. Renz) var. typica (Gandolfi) ,
Ayala, Assoc. Mex. Geol. Petrol., Bol., vol. 6, Nos. 11-12, p- 418,
pl. 12, fig. 3.
Globotruncana (Rotalipora) appenninica appenninica Renz,
Kupper, Contr. Cushman Found. Foram. Res., pe lias ples:
figs. 2a-c.
Globotruncana appenninica Renz, Sacal and Debourle, Soc. Géol.
France, n. sér., Mém. No. 78, p. 58, pl. 25, figs. 9; 19, 20.
Globotruncana (Rotalipora) appenninica appenninica O. Renz,
Gandolfi, Contr. Cushman Found. Foram. Res., vol. 8, pt. 2; p:
GOS ply Oy ign 3:
Rotalipora brotzeni (Sigal), Bolli, et al., U.S. Nat. Mus., Bull.
No. 215, p. 41, pl. 9, figs. 7a-c.
Not Rotalipora cf. R. appenninica (O. Renz), Bolli, et al., US.
Nat. Mus., Bull., No. 215, p. 41, pl. 9, fig. 5.
Rotalipora globotruncanoides Sigal, Banner and Blow, Paleon-
tology, vol. 2, pt. 1, pl. 2, fig. 4.
Rotalipora (Thalmanninella) appenninica appenninica (Renz),
Klaus, Eclogae. Geol. Hely., vol. 52, No. 2, p. 808, pl. 3, rigs.
3a-c.
Rotalipora appenninica (O.
Micropaleont., vol. 7, No. 38,
12a-c.
Rotalipora greenhornensis (Morrow), Loeblich and Tappan
(part), Micropaleont., vol. 7, No. 3, pp. 299-301, pl. 7, figs. 10a-c;
not 5-9.
Rotalipora evoluta Sigal, Ayala, Soc. Geol. Mex., Bol., vol. 25,
No. 1, pp. 26-28, pl. 4, figs. 2a-c; not 3a-c; pl. 10, figs. 2a-c.
Rotalipora greenhornensis (Morrow), Loeblich and Tappan
Renz), Loeblich and Tappan,
pp. 296, 297, pl. 7, figs. lla-c,
290 PALAEONTOGRAPHICA AMERICANA (V, 37)
(part), Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2, pp.
659-660, fig. 528: 3a-c; not 4a-c.
1964. Not Rotalipora appenninica (Renz), Todd and Low, Deep-Sea
Research, vol. 11, p. 405, pl. 2, figs. 6a-c.
Emended definition.—Test trochospiral, spiroconyvex to
nearly biconvex (mean T’X/TX value for 17 measured
WAS/ADSK selected lectotype
—0(.66) , sharply angled by a single keel; single keel present
specimens—0.76; value of
in early whorls except for embryonic whorl. Chambers ar-
ranged in about two and one-half to three whorls; six to
eight chambers in final whorl; chambers expanding in
size rapidly between early part of final whorl and late part
of preceding whorl; chambers in final whorl expand in size
more slowly. Chambers elongate, crescent-shaped spirally;
separated by radially arranged curved, raised, slightly bead-
ed sutures. Chambers wedge-shaped umbilically; separated
by radial, curved to slightly curved somewhat raised, beaded
sutures. Umbilicus deep. Sutural supplementary apertures
present on umbilical side of test on posterior (umbilically
directed ends) of sutures. Primary aperture extraumbilical-
umbilical in position. Outer wall radial hyaline perforate
except for keel which is radial hyaline imperforate. Septal
walls microgranular hyaline, slightly perforate.
appenninica (QO. Renz) was
originally described in syntypic series by Renz (cf. synon-
Remarks.—Rotalipora
omy above) in thin-section from the Cenomanian of the
central Appennines of Italy. Since R. appenninica has been
confused frequently with R. evoluta Sigal, R. cushmani
(Morrow) , and R. greenhornensis (Morrow) , it seems best
to stabilize its taxonomic status through the selection of a
lectotype. Thus, the form figured by O. Renz (1936) in
plate 8, figure 4 is formally designated the lectotype of
Globotruncana appenninica O. Renz; the specimen figured
by O. Renz (1936) in figure 2, p. 14
Globotruncana appenninica O. Renz is formally designated
(upper right) as
a paralectotype. Measurements of the lectotype and para-
lectotype are presented in ‘Text-figure I]. The type local-
ity of the lectotype is section II, bed 3:*°5-10cm. dicke Banke
erauer Plattenkolke. Fossilien: Zahlreiche Globigeriniden
und G. appenninica (Taf. VI, fig. 7 und i; ‘Taf. VIII, fig.
4) (©. Renz, 1936; p. 33),
Because Renz’s syntypes included either drawings or
photographs of specimens occuring in rock thin-section, it is
difficult to obtain a clear concept of the nature of this
species externally. ‘The external appearance of R. appen-
ninica can be substantiated, however, in two ways: (1)
through the examination of matrix free topotypes from the
type level of R. appenninica and (2) by sectioning free
specimens and comparing their form with that of the
selected lectotype and paratype. Through the kindness of
H. P. Luterbacher, the writer was able to examine material
from the type level of R. appenninica and to compare this
material with his American material. Numerous sections of
American specimens of this species have been made during
the course of this study. These sections have been carefully
measured and compared to the lectotype and paralectotype
selected herein (cf. Text-figure 11). The specimen figured
in Plate 51 (figures 10-12) of this work is believed to em-
body the concept of this species externally,
R. appenninica differs from R. evoluta Sigal externally
(1) by having curved rather than straight sutures umbili-
cally; (2) by lacking an umbilical shoulder; and (3) by
having a somewhat thicker test peripherally. In thin-section
R. appenninica differs from R. evoluta (1) by having some-
what greater posterior and anterior keel angles and (2) by
having somewhat more vaulted chambers spirally and um-
bilically. It is likely that R. appenninica evolved from a
R. evoluta ancestor.
R. appenninica differs externally from R. greenhornen-
sis (Morrow) by being more conyex spirally. Form analy-
sis of sectioned specimens of both species indicates that the
most significant measurements are their T’X/TX values.
Text-figure 14 is a scatter plot of T’X/TX and D-D’ values
of R. appenninica and R. greenhornensis. On the basis of
the first standard deviations of ‘T’X/TX values of R. ap-
penninica and R. greenhornensis, T’X/TX—0.90 is taken
as the upper limit of R. appenninica and T’X/TX=1.12 is
taken as the lower limit of R. greenhornensis (cf. Table 2).
Specimens having T’X/TX values greater than 0.90 and less
than 1.12 are considered transitional in this report.
R. appenninica differs externally and in thin-section
from R. cushmani (Morrow) by having less inflated cham-
bers both spirally and umbilically and by having a propor-
tionally smaller umbilicus (cf. Text-figures 11 and 12).
Text-figure 13 is a scatter plot of D-D’/U-U’ to T’X/TX
for R. appenninica and R. cushmani. On the basis of their
first standard deviations the upper limit of R. cushmani is
defined as D-D’/U-U’=2.0, whereas the lower limit of R.
appenninica is defined as D-D’/U-U’=2.21. Specimens hav-
ing D-D’/U-U’ greater than 2.0 and less than 2.21 are con-
sidered transitonal herein.
The specimens figured by Bolli (1951, p. 193, plas,
figs. 1-3) as G. appenniniea cf. alpha Gandolfi seems to be
referrable to Rotalipora evoluta Sigal inasmuch as the su-
tures on the umbilical side are straight rather than curved.
Subbotina (1953, p. 159) figured numerous specimens
of Rotalipora appenninica from the Cenomanian of Russia.
Loeblich and Tappan (1961, p. 297) felt that the specimens
figured by Subbotina in plate | in figures 7 and 8 should be
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 29]
included under R. greenhornensis. However, the writer feels
that only the specimen illustrated in figure 8 should be re-
ferred to R.
is convex spirally and represents a typical R. appenninica.
The specimen figured by Hagn and Zeil (1954, pl. 1,
figs. la-c) as Rotalipora appenninica seems referable to
Rotalipora cushmani (Morrow) .
The topotype of Rotalipora brotzeni (Sigal) figured
by Bolli, et al. (1957, p
greenhornensis. The form figured in figure 7
. 41, pl. 9, figs. 7a-c) and again by
TEXT-FIGURE 11
appenninica
(O. Renz)
PE 1059
PE 1062 ++
MX 156
Rotalipora
0.077 |0.087 0.8
= bf
8.
i)
°
3.0 2s
0.337) 0.322}0.350]0.
Brin:
Ja
All measurements in millimeters.
= Renz (1936, pl. 8, fig. 4).
= Renz (1936, fig. 2, p. 14; upper right).
= Similar to Renz (1936, p. 14, fig. 2,
= R. appenninica transitional to R. greenhornensis.
++ = R. appenninica transitional to R. cushmani.
lower left).
Loeblich and Tappan (1961, pp. 299-301, pl. 7, figs. 10a-c;
659-661, fig. 528: 3a-c) is regarded as Rotalipora
appenninica because of the marked conyexity of the spiral
side of the test (I’X/TX=about 0.71). Thalminella
brotzeni Sigal (1948, pl. 1, figs. is referrable to R.
greenhornensis as an approximate measurement of its T7X/
TX value from Sigal’s drawings indicates that T’/X/TX=
1.13, thus falling within the lower limits of R.
1964, pp.
5a-c)
greenhornen-
SIS.
PE 1079 -++
MX 156
PE 1080
PE' 1070 +
MX 156
PE 1073 +
MX 156
PE 1074 **x
S ° i) © |} PE 1075
° i= Xo S577;
ron r=)
PE 1076
as)
H
394 0.602
S
o
ty
ra foo feo oreo or nw foe
Sg
~ re fo)
Ww ° Ww
jo)
\o
N bs
w °
Lectotype designated herein.
Paralectotype designated herein.
292 PALAEONTOGRAPHICA AMERICANA (V, 37)
Range.—Rotalipora s.s. assemblage zone.
Occurrence.—During the course of this study R. appen-
ninica has been observed in the Cenomanian portion of the
San Felipe formation at Boca Canyon south of Monterrey,
Mexico; at Mamulique Pass to the north of Monterrey,
Mexico; and in the Cuesta del Crura limestone and upper
Tamaulipas formation at Peregrina Canyon, northwest ol
Ciudad Victoria, Mexico. R. appenninica has been observed
in the Eagle Ford group in the Lake Waco and Chispa Sum-
mit formations.
R. appenninica is known from the Cenomanian of
Cuba, Puerto Rico, Trinidad, and South America.
Loeblich and Tappan (1961, pp. 296-297) noted R.
appenninica from the Maness formation of Texas. It is also
known from the Cenomanian of Switzerland, Italy, Algeria,
France, Germany, Spain, and Russia.
Rotalipora cushmani (Morrow)
Plate 51, figures 6-9; Plate 101, figures 5-7
1934. Globorotalia cushmani Morrow, Jour. Paleont., vol. 8, p. 199,
pl. 31, figs. 2, 4.
1942. Rotalipora turonica Brotzen, Sver. Geol. Unders., Ser. C., No.
451, Ars. 36, No. 8, p. 32, text-figs. 10, 11 (4).
1945. Globotruncana alpina Bolli, Eclogae Geol. Helv., vol. 37, No. 2
pp- 224, 225, pl. 9, figs. 3, 4.
1946. Globorotalia cushmani Morrow, Cushman, U.S. Geol. Sur., Prof
Paper, No. 206, p. 152, pl. 62, figs. 9a-c.
1948. Globotruncana benacensis Cita, Riv. Ital. Pal., vol. 54, No. 4, pp.
147, 148, pl. 3, figs. 3a-c.
1948. Rotalipora cushmani (Morrow), Sigal, Instit. Franc. Petrole,
Rev., vol. 8, No. 4, p. 96, pl. 1, fig. 2; pl. 2, fig. 1.
1950. Globotruncana (Rotalipora) montsalvensis Mornod, Eclogae
Geol. Helv., vol. 42, No. 2, p. 584, text-figs. 4(1); 7(1, 2).
1950. Globotruncana (Rotalipora) montsalvensis var. minor Mornod,
Fclogae Geol. Helv., vol. 42, No. 2, p. 581, text-fig. 8 (la-c, 2-4) .
1950. Globotruncana (Rotalipora) turonica (Brotzen) , Reichel, Eclo-
gae Geol. Helv., vol. 42, No. 2, p. 607, pl. 16, fig. 5; pl. 17, fig. 5.
1954. Globcrotalia cushmani Morrow, Frizzel, Univ. Texas, Bur. Econ.
Geol., Rept. Invest. 22, p. 129, pl. 20, fig. 28.
1954. Rotalipora cushmani (Morrow), Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. 1, p. 29, pl. 1, figs. 3; pl. 4, figs. 8-10.
1954. Rotalipora turonica Brotzen, Hagn and Zcil, Eclogae Geol.
Helv., vol. 47, No. 1, pp. 27, 28, pl. 1, fig. 5; pl. 4, fig. 4; not
fig. 3.
1954. Rotalipora montsalvensis Mornod, Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. 1, p. 29, pl. 1, fig. 4; pl. 5, fig. 2.
1954. Rotalipora cushmani (Morrow), Ayala, Assoc. Mex., Geol.
Petrol., Bol., vol. 6, Nos. 11, 12, p. 418, pl. 16, fig. 2.
1954. Rotalipora turonica Brotzen, Ayala, Assoc. Mex. Geol. Petrol.,
Bol., vol. 6, Nos. 11-12, p. 422, pl. 14, fig. 2.
1956. Rotalipora cushmani (Morrow), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, p. 537, pl. 20, figs. 10-12.
1957. Rotalipora cushmani (Morrow), Sacal and Debourle, Soc. Géol.
France, n. sér, Mém., No. 78, p. 58, pl. 25, figs. 6-8, 13, 16, 17.
1957. Rotalipora turonica Brotzen, Bolli, et al., U.S. Nat. Mus., Bull.
No. 215, p. 41, pl. 9, figs. 6a-c.
1957. Globotruncana (Rotalipora) cf. G. (R.) turonica Brotzen,
Edgell, Micropaleont., vol. 3, No. 2, p. 109, pl. 1, figs. 16-18.
1960. Rotalipora (Rotalipora) cf. montsalvensis var. minor Mornod,
Klaus, Eclogae Geol. Helv., vol. 52, No. 2, pp. 813, 814, pl. 5,
figs. la-c.
1960. Rotalipora (Rotalipora) turonica Brotzen var. expansa Car-
bonnier, Klaus, Eclogae Geol. Helv., vol. 52, No. 2, pp. 815, 816,
pl. 5, figs. da-c.
1960. Rotalipora (Rotalipora) cushmani (Morrow), Klaus, Eclogae
Geol. Hely., vol. 52, No. 2, pp. 814-815, pl. 5, figs. 2a-c.
1961. Rotalipora cushmani (Morrow), Loeblich and Tappan, Micro-
paleont., vol. 7, No. 3, pp. 297, 298, pl. 8, figs. 1-10.
1964. Rotalipora montsalvensis Mornod, Renz, Luterbacher, and
Schneider, Eclogae Geol. Helv., vol. 56, No. 2, p. 1089, pl. 7, figs.
la-c.
1964. Rotalipora montsalvensis minor Mornod, Renz, Luterbacher,
and Schneider, Eclogae Geol. Hely., vol. 56, No. 2, p. 1089, pl. 7,
figs. 2a-c.
1964. Rotalipora cushmani (Morrow), Loeblich and Tappan, Treatise
on Invert. Paleont., pt. C, Protista 2, vol. 2, pp. 659-661, fig.
528: la-c; 2a-c.
Remarks.—Rotalipora cushmani (Morrow) is closely
related to Rotalipora appenninica (Renz). Transitional
forms are common in the North American Upper Ceno-
manian. Rotalipora cushmani can be differentiated from
Rotalipora appenninica (Renz) (1) by the more inflated or
vaulted nature of its chambers both spirally and umbilical-
ly; (2) by the larger size of its umbilicus relative to its
diameter (D-D’/U-U’); and (3) by the markedly de-
pressed nature of its sutures on the umbilical side. Text-
figure 12 shows form analysis measurements of sectioned
free specimens of R. cushmani. ‘Text-figure 13 is a scatter
plot of D-D’/U-U’ to T’X/TX for R. cushmani and R.
appenninica. As noted previously the lower limit of R. ap-
penninica is defined herein as D-D’/U-U’=2.21 whereas
the upper limit of R. cushmani is taken as D-D’/U-U’/=2.0.
Specimens having ratios greater than 2.0 and less than 2.21
are considered transitional.
‘The writer agrees with Bronnimann and Brown (1956,
p. 538) and Loeblich and Tappan (1961, p. 298) that R.
turonica Brotzen is a junior synonym of R. cushmani (Mor-
row). Reichel (1958, p. 605) noted the similarity between
these two forms, but stated that R. cushmani could be dif-
ferentiated from R. turonica because it had a flatter spire
(higher T’X/TX value). Loeblich and Tappan (bid.)
clearly demonstrated that both the higher spired form
(=R. turonica) and the lower spired form (=R. cush-
mani) occur together in topotypic material of R. cushmani
from the Greenhorn limestone. Form analysis of R. cush-
mani indicates that there is a considerable variation in the
T’X/TX value of R. cushmani at any given North Ameri-
can locality. Furthermore, there seems to be little significant
difference in the geologic range of either the high-spired
form or the low-spired form.
Rotalipora thome: Hagn and Zeil (1954) is regarded
at present as a distinct species related to Rotalipora cush-
mani (Morrow). R. thomei is extremely convex spirally
and has low T’X/TX values (see Text-figure 17).
Globotruncana (Rotalipora) montsalvensis Mornod
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
and Globotruncana (Rotalipora) montsalvensis vay. minor
Mornod are not sufficiently different from R. cushmani to
be maintained as valid species. Hence, in this paper they are
regarded as junior synonyms of R. cushmani.
Globotruncana alpina Bolli (1945) is only known from
vertical (axial) sections. Form analysis measurements made
from Bolli’s photomicrographs of the type specimens of G.
alpina fall within the limits of R. cushmani (cf. Text-fig-
ures 12, 13). The writer agrees with Bronnimann
Brown (1956, p. 538) that G. alpima should be regarded
as a junior synonym of R. cushmant.
and
The holotype and paratypes of Globorotalia cushmani
Morrow (Cushman Collection, USNM) were examined
during the course of this study.
Range.—Rotalipora assemblage zone; R. cushmani—
ereenhornensis subzone.
TEXT-FIGURE 12
357
PE 1087
PE 1088
PE 1089
PE 1099
TX
cushmani
0.224 |O.
-112]0.042]0. o42/0.084|
0°}10.0°]19. ales
43.0°]40.0°]| 36. dete
266]0. ch ol
ae “fash .187 [0.261 sake fu 250 8
All measurements in millimeters.
IF 5(0=
Angle XC
Angle XD T
E
0.
28.0°
De
PE 1100
TX 5
293
Occurrence.—R. cushmani has been observed in Mex-
ico in the upper portion of the ‘Tamaulipas limestone at
Peregrina Canyon northwest of Ciudad Victoria and in the
San Felipe formation at Boca Canyon somewhat south of
Monterrey (Text-figures 1-2). In Texas R. cushmani occurs
in the Eagle Ford group in the Britton, Lake Waco,
Chispa Summit formations. It is particularly abundant in
the Chispa Summit formation at Chispa Summit, Jeff Davis
County. Loeblich and TVappan (1961, p. 298) noted that
R. cushmani has been recorded under various names from
the Greenhorn limestone of Kansas and South Dakota; the
Atkinson formation of Georgia, “Antelope shale”
of California. R. cushmani occurs throughout the Upper
Cenomanian of Eurasia, Africa, and Australia. The writer
has lately seen this species in thin-section from the Upper
Cenomanian of Puerto Rico.
and
and the
fig.3
fig.8
fig.9
eil *
Zeil *
1954 P1.4,
Hagen &
1954 P1.4,
Z
Hagn & Zeil *
1b 45
Hagn & Zeil *
1954 P1.9, fig.10
Bolli 1945 **
Bolli 1945 **
Ee 1101
1954
Hagn &
ra
=e a ie be <
Papa a
°
0.354 af 289
0.23
293
is)
i
* = Hagn and Zeil 1954, pl. 4, fig. 3 = R. turonica Brotzen of Hagn and Zeil;
figs. 8-10 = R. cushmani (Morrow) of Hagn and Zeil.
** = Globotruncana alpina Bolli (1945, pl. 9, figs. 3-4; fig. 3 = holotype).
204
TEXT-FIGURE 13
ene
Ler = Wansitione! forme
PALAEONTOGRAPHICA AMERICANA
(V, 37)
$4 pl big 3
11954 pl a hig O
A VWISE pl dihig 9
11, 1954. pl 4 fig 10
el, 19!
’
or 1936, pl Bhig 4
nx. 1936. fig 2p 14. upper right
= =>]
27 °
e
26 ei! '
25 5 Ks
e
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24
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23 e-10 - 10}
.
22
. Fo or a
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als
20+ O ° 8
oo oe o-3
Mg 0
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o o-4
le
| ° 2-0
Whe °) e o- 5
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Ve
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010 02 03 o4 0s 06 07 o8 09 10 mn) 12
T xT
TEXT FIGURE Is
O Retelipere qreenhermensis | Morren na, 1996, Big a
© Rerelipere eppenninice (O Rens) aT onal yr 1998 Ie 2 M4 woper right
0 700 ——_— ——
| 5 |
a |
. . = . |
0 600}- 0 oun !
.
e |
s L . 1
; ; ‘ . ;
. e -
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Tx, 1K
Rotalipora evoluta Sigal
Plate 49, figures 12-14; Plate 53, figures 6-8; Plate 98, figure 12
1948. Rotalipora cushmani var. evoluta Sigal, Inst. Franc. Petrol.,
Rev., vol. 3, No. 4 p. 100, pl. 1, fig. 3; pl. 2, fig. 2.
1940. Globorotalia delrioensis Plummer, Tappan, Jour. Paleont., vol.
14, No. 2, p. 123, pl. 19, fig. 14.
1946. Globorotalia delrioensis Plummer, Loeblich and ‘Tappan, Jour.
Paleont., vol. 20, No. 2, p. 257, text-fig. 4B.
1948. Globorotalia almadenensis Cushman and Todd, Contr. Cushman
Found. Foram. Res., vol. 24, pt. 4, p. 98, pl. 16, fig. 24.
1950. Globotruncana (Rotalipora) appenninica Renz, Mornod (part),
Eclogae Geol. Helv., vol. 42, No. 2, pp. 579-582, text-fig. 3:
la-c, 2a-c; not 3a-c; text-fig. 4; not 3a-c; ?4a-c; text-fig. 5: not
la-c; pl. 15, figs. la-c.
1951. Globotruncana appenninica cf. alpha Gandolfi, Bolli, Jour.
Paleont., vol. 25, No. 2, p. 193, pl. 34, figs. 1-3.
1952. Globotruncana (Rotalipora) appenninica O. Renz var. typica
Gandolfi, Bolli in Church, 1952, Contr. Cushman Found. Foram.
Res., vol. 3, pt. 2, p. 69, text-fig. 2.
1955. Globotruncana (Rotalipora) evoluta Sigal, Kiipper, Contr.
Cushman Found. Foram. Res., vol. 6, pt. 3, p. 115, pl. 18, figs.
3a-c.
1955. Globotruncana (Rotalipora) appenninica appenninica Renz,
Kipper, Contr. Cushman Found. Foram. Res., vol. 6, pt. 3, p-
114, pl. 18, figs. 2a-c.
1957. R. cf appenninica (O. Renz), Bolli, et al., U.S. Nat. Mus., Bull.,
No. 215, p. 41, pl. 9, figs. 5a-c.
1960. ? Rotalipora (Thalmanninella) evoluta (Sigal), Klaus, Eclogae
Geol. Helv., vol. 52, No. 2, p. 810, pl. 4, figs. 3a-c.
4
1961. Rotalipora evoluta Sigal, Loeblich and Tappan, Micropaleont.,
vol. 7, No. 3, pp. 298-299, pl. 7, figs. 1-4.
1961. Rotalipora greenhornensis (Morrow), Loeblich and Tappan
(part) , Micropaleont., vol. 7, No. 3, pp. 299-301, pl. 7, figs. 5-6c,
not figs. 7a-10c.
1962. Not Rotalipora evoluta Sigal, Ayala, Soc. Geol. Mexicana, Bol.,
vol. 25, No. 1, pp. 26, 27, pl. 4, figs. 2a-c; pl. 10, fig. 2a-c.
1964. Rotalipora ct. appenninica evoluta Sigal, Renz, Luterbacher, and
Schneider, Eclogae Geol. Helv., vol. 56, No. 2, p. 1088, pl. 8, figs.
3a-c.
1964. Not Rotalipora evoluta Sigal, Todd and Low, Deep-Sea Rsearch,
vol. 11, p. 46, pl. 2, figs. 3a-c.
Remarks.—Through the kindness of J. Sigal the writer
was able to obtain specimens corresponding to Sigal’s holo-
type (fig. 3) and to Sigal’s paratype (fig. 2). The speci-
mens corresponding to the holotype resemble best the speci-
men figured by Bolli, et al., (1957, pl. 9, figs. 5a-c) as
Rotalipora cf. R. appenninica Renz. The specimen corres-
ponding to the paratype resembles the form figured herein
as Rotalipora evoluta (Plate 53, figs. 6-8) and by Loeblich
and ‘Tappan (1961, plate 7, figures 3a-c) as Rotalipora
GuLrF CRETACEOUS FORAMINIFERA: PESSAGNO
evoluta. The holotype is convex spirally whereas the para-
type is more convex umbilically and has a relatively flat
spiral side.
Rotalipora evoluta Sigal is somewhat similar to Rotali-
pora appenninica (Renz). It differs from R. appenninica
(1) by having straight, often depressed sutures on the um-
bilical side; (2) by usually possessing well-developed umbi-
lical shoulders; (3) by having somewhat less inflated cham-
bers when seen in axial-section; (4) by having lower pos-
terior and anterior keel angles; and (5) by often showing
a more rapid increase in chamber size.
R. evoluta is rare in the material examined during this
study. Only two specimens were measured in thin-section
(Text-figure 15).
Some of the specimens figured by Loeblich and Tap-
pan (1961, pl. 7, figs. 5-6C) as R. greenhornensis (Morrow)
may be referrable to R. evoluta. They show straight sutures
umbilically and well-developed umbilical shoulders. Speci-
mens referred to R. evoluta Sigal by Ayala (1962) are as-
signable to R. appenninica (Renz). Ayala’s specimen fig-
ured in plate 4, figs. 2a-c shows well-developed curved su-
tures umbilically and lacks prominent umbilical shoulders.
The writer has examined the holotype (Cushman Col-
lection, USNM)
and Todd and agrees with Loeblich and Tappan that it
should be placed in synonomy under R. evoliuta Sigal. The
holotype of R. almadenensis seems more similar to Sigal’s
paratype of R. evoluta in that it possesses a relatively flat
spiral side.
of Globorotalia almadenensis Cushman
Rotalipora evoluta Sigal represents the oldest Ceno-
manian species of Rotalipora s.s. known to date in the
North American section. It is likely as suggested by Loe-
blich and Tappan (1961, p. 297) that R. evoluta is ances-
tral to R. appenninica (Renz). The latter species in turn
gave rise to R. cushmani (Morrow) and R. greenhornensis
(Morrow) .
Range.—Rotalipora s.s.
subzone.
assemblage zone; R. cvoluta
Occurrence.—R. evoluta was noted in this study only in
the Grayson formation (Del Rio clay) of Texas.
Rotalipora evoluta is also known from the Franciscan
complex of California where it occurs in the Calera lime-
stone near Los Gatos. It occurs in the Cenomanian of Trini-
dad, Switzerland, and Algeria.
Rotalipora greenhornensis (Morrow)
Plate 50, figure 3; Plate 51, figures 13-21; Plate 101, figures 3-4
1934. Globorotalia greenhornensis Morrow, Jour. Paleont., vol. 8, p
LOO pls397 fie.) We
1940.
1946.
1948.
1948.
1948.
1950.
no
©
ot
TEXT-FIGURE 15
evoluta Sigal
io)
yy
°
a
dq
iss}
7)
fe)
4
0
a
x
“NK
PE 1085
Type 5-B
PE 1086
Angle XDU
0.140]0.140
DE
ve
y
1
All measurements in
millimeters.
Planulina greenhornensis (Morrow), Cushman, Contr. Cushman
Lab. Foram. Res., vol. 16, pt. 2, p. 37, pl. 7, fig. 1.
Planulina greenhornensis (Morrow). Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 159, pl. 65, figs. 3a-c.
Rotalipora globotruncanoides Sigal, Instit. Franc. Petrole, Rev.,
vol. 3, No. 4, p. 100, pl. 1, fig. 4; pl. 2, figs. 3-5.
Thalmanninella brotzeni Sigal, Instit. Franc. Petrole., Rev., vol.
3, No. 4, p. 102, pl. 1, fig. 5; pl. 2, figs. 6, 7.
Globorotalia decorata Cushman and Todd, Contr. Cushman Lab.
Foram. RKes., vol. 24, pt. 4, p. 97, pl. 16, fig. 21.
Not Globotruncana (Thalmanninella) brotzeni Sigal, Mornod.
Eclogae Geol. Hely.. vol. 42, No. 2, p. 586, text-fig. 9: l-ac.
296 PALAKONTOGRAPHIGCA AMERICANA (V, 37)
1950. Globotruncana (Rotalipora) appenninica O. Renz var. typ ca
Gandolfi, Mornod, Eclogae Geol. Helv., vol. 42, No. 2, p. 582,
text-fig. 9: 2a-c.
1952. Rotalipora globotrucanoides Sigal, Sigal, 19th Congr. Géol.
Internat., Monogr. Rég., Alger, ser. 1, No. 26, p. 26, text-fig. 24.
1953. Rotalipora appenninica (Renz), Subbotina (part), Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 159,
pl. 1, figs. 8a-c; not figs. 5a-c; 6a-c; 7a-c; not pl. 2, figs. la-c; 2a-c.
1954. Rotalipora See naa Sigal, Hagn and Zeil, Eclogae
Geol. Helv., vol. 47, No. 1, pp. 23-25, pl. 4, fig. 7
1955. Not Globotruncana Peers Pabotemcane ides Sigal, Kiip-
per, Contr. Cushman Found. Foram. Res., vol. 6, pt. 3, p. 113,
pl. 18, figs. la-c.
1955. Globotruncana (Thalmanninella) sp. Kupper, Contr. Cushman
Found. Foram. Res., vol. 6, pt. 3, p. 115, pl. 18, figs. 4a-c.
1956. ?Globotruncana n. sp. indet. ete Contr. Cushman Found.
Foram. Res., vol. 7, pt. 2, p. 44, pl. 8, figs. 3a-c.
1956. Thalmanninella greenhornensis (Morrow), Bronnimann and
Brown, Eclogae Geol. Helv., vol. 48, No. 2, p. 535, pl. 20, figs.
7-9,
1957. Globotruncana (Rotalipora) appenninica appenninica O. Renz,
Gandolfi, Contr. Cushman Found. Foram. Res., vol. 8, pt. 2,
p- 60, p. 9, fig. 2
1957. Rotalipora globotruncanoides Sigal, Sacal and Debourle, Soc.
Géol. France, n. sér., Mém. No. 78, pl. 25, ?fig. 1; fig. 3; ?figs.
lb:
1957. Not Rotalipora brotzeni (Sigal), Bolli, et al., U.S. Nat. Mus.,
Bull., No, 215, p. 41, pl. 9, figs. 7a-c.
1959. Not Rotalipora globotruncanoides Sigal, Banner and Blow, Pale-
ontology, vol. 2, pt. 1, pl. 2, fig. 4.
1960. Rotalipora (Thalmanninella) greenhornensis (Morrow), Klaus,
Eclogae Geol. Helv., vol. 52, No. 2, p. 805, pl. 2, figs. 3a-c
1960. ?Rotalipora (Thalmanninella) brotzeni Sigal, Klaus. Eclogae
Geol. Helv., vol. 52, No. 2, p. 805, pl. 3, figs. la-c.
1961. Rotalipora greenhornensis (Morrow), Loeblich and ‘Tappan
(part), Micropaleont., vol. 7, No. 3, pp. 299-301, pl. 7, figs. 7a-9c;
not figs. 5-6c, 10a-c.
1962. Rotalipora BeOS (Morrow) , Ayala, Soc. Geol. Mexi-
cana, Bol., vol. 25, No. 1, pp. 28-30, ?pl. 5, figs. 3a-c; pl. 10, figs
3a, b.
1964. Rotalipora greenhornensis (Morrow) ,
(part), Treatise on Invert. Paleont., pt.
C659-C661, fig. 528; 4da-c; not 3a-c.
Loeblich and Tappan
C, Protista 2, vol. 2, pp.
Remarks.—
closely related to Rotalipora appenninica (Renz) and seems
Rotalipora greenhornensis (Morrow) _ is
to have been derived from the latter species largely by the
flattening of the spiral side of the test. R. greenhornensis
differs from R. appenninica chiefly by having a less convex,
nearly planiform spiral side with a T’X/TX value of 1.12
or higher. In addition, it usually is somewhat less lobulate
than R. appenninica and has somewhat more closely spaced
and numerous chambers in the last whorl.
The holotype of Globorotalia greenhornensis Morrow
(Cushman Collection, USNM) was examined during the
course of this study. It shows a prominent extraumbilical
aperture, well-developed sutural supplementary apertures,
raised sutures on the spiral side, a relatively planiform
spiral side, and nine chambers in the last whorl. Approxi-
mate measurements of its T’X/TX value from plate 20,
figure 9 of Bronnimann and Brown (1956) indicate that
TEXT-FIGURE 16
reenhornensis
(Morrow)
PE 1057
MX 156
PE 1060
MX 156
Rotalipora
0.583) 0.504
DS
o
i)
ND
x
q Gal Oo ~
wo lwo oO wo 0
ow o o ow
i a) aw dea
We [=> a! a ops iQ 2
allele fot (o)Balat
G PE 1071
S TX5
PE 1072
MX 156
Gals
aera
:
Ps fo ca
All measurements in millimeters.
* R. greenhornensis transitional to R. appenninica.
it has a T’X/TX value of 1.47. In thin-section it most
likely would resemble specimen PE 1061 figured herein in
Plate 101, figure 3.
Text-figure 16 shows form analysis measurements of
sectioned free specimens of R. greenhornensis; means and
standard deviations of form analysis measurements are
shown in Table 2. Text-figure 14 is a scatter plot comparing
T’X/TX and D-D’ value of R. greenhornensis and R. ap-
penninica, As noted previously, T’X/TX—1.12 has been
taken as the lower limit of R. greenhornensis herein; like-
wise IT’X/TX—0.90 is taken as the upper limit of R. ap-
penninica. Specimens having T’X/TX values greater than
0.90 and less than 1.12 are considered transitional between
these 2 species.
A small number of names that were included in the
synonomy of Rotalipora greenhornensis (Morrow) by
Loeblich and Tappan (1961, p. 299) are not considered
R. greenhornensis by the writer. For example, the form
figured by Mornod (1950, see synonymy) as Globotruncana
(Thalmanninella) brotzeni Sigal should be included in
synonymy under R. appenninica, Measurements of this spe-
cimen’s approximate T’X/TX value from Mornod’s draw-
GuLir Crerackous FORAMINIFERA: PESSAGNO
ing indicate that T’X/TX=—0.75. Thus, this specimen
clearly falls within the limits of R. appenninica (Renz)
cf. Text-figure 14). The holotype of Thalmanninella brot-
zeni Sigal itself, however, shows an approximate ‘T’7X/TX
value of 1.12 and appears to fall within the lower limits
(established herein) for R. greenhornensis (Morrow) . Like-
wise, the specimen figured by Bolli, et al., (1957, pl. 9, figs.
7a-c) and again by Loeblich and Tappan (1961, pl. 7,
figs. 10a-c; 1964, figs. 3a-c) as Rotalipora brotzeni (Sigal)
and Rotalipora greenhornensis (Morrow) is referrable to
R. appenninica as it has an approximate T’X/TX value of
0.76. The sectioned specimens of Rotalipora globotruncan-
oides Sigal figured by Banner and Blow (1959, see syno-
nymy) has a T’X/TX of 1.0 and, therefore, appears to be
transitional between R. appenninica (Renz) and R. green-
hornensis (Morrow) .
The two specimens from the Blake Plateau figured by
Loeblich and Tappan (1961, pl. 7, figs. 5-6c only) as R.
greenhornensis may be referrable to R. cvoluta Sigal as they
show well-developed umbilical shoulders and straight, ra-
dial, depressed sutures umbilically.
It is conceivable that Rotalipora grecnhornensis (Mor-
row) is a junior synonym of Rotalia decckei Franke (1925,
pp. 88, 90, pl. 8, figs. 7a-c). Franke’s drawings indicate a
close similarity to R. greenhornensis. Dalbiez (1957, pp.
187-188) demonstrated from a study of Franke’s type speci-
mens that Rotalia deeckei is definitely assignable to Rotali-
pora.
Range.—Rotalipora s.s. assemblage zone; R. cushmani—
greenhornensis subzone.
Occurrence.—In this study Rotalipora greenhornensis
(Morrow) has been found in the upper portion of the
‘Tamaulipas limestone and in the Cuesta de Crura limestone
at Peregrina Canyon northwest of Ciudad Victoria, Mexico.
It is abundant in the lower portion (Upper Cenomanian)
of the San Felipe formation exposed at Boca Canyon south
of Monterrey, Mexico, and at Mamulique Pass along the
Nuevo Laredo—Mexico City highway (Rt. 85) north of
Monterrey, Mexico. In Texas, R. greenhornensis occurs in
the Upper Cenomanian portion of the Eagle Ford group at
Lozier Canyon, Terrell County, at Chispa Summit, Jeff
Davis County, and at Waco, McLennan County (Text-fig-
unen2)\e
Rotalipora
North America from the Greenhorn limestone (Hartland
shale member) of Kansas. The form figured by Kipper
(1956, see synonomy) as “Globotruncana n. sp. indet.” from
the “Antelope shale” of California may be referrable to this
ercenhornensis is known elsewhere in
297
TEXT-FIGURE 17
6
realen, 5)
Hagn & Zeil 1954
fig.
Hagn & Zeil 1954
Pils Aye
Hagn & Zeil
kG ts
ou
uy
fe)
od
al
o
v
je}
4
UUs
TX
Tex
XD
XD’
thomei
0.618
af
0.027
Sates
on
All measurements in
millimeters.
species though Kiipper’s description and figures seem con-
tradictory.
R. greenhornensis has been figured under various
names from the Cenomanian of Germany, Switzerland, Mor-
occo, Bavaria, France, Russia, and Algeria. It is also known
from the Cenomanian of Cuba (cf. Ayala 1962; synonymy
herein) and from Late Cenomanian of Puerto Rico (Pes-
Sagno, In progress) .
298 PALAEONTOGRAPHICA AMERICANA (V, 37)
Family MARGINOTRUNCANIDAE Pessagno, n. fam.
Type genus.—Marginotruncana Hotker (1956) (emend-
ed herein).
Description.—Coiling trochospiral; chambers spherical,
ovate, hemispherical, angular rhomboid, or angular trun-
cate; primary aperture variable in position: extraumbilical-
umbilical to nearly umbilical with large portici extending
about midway into umbilicus and having infralaminal but
not intralaminal accessory apertures (cf. Pl. 57, fig. 7). Non-
carinate or with imperforate peripheral band, single or
double keel. Outer wall radial hyaline perforate; septal
wall microgranular hyaline, finely perforate; portici micro-
granular hyaline, perforate (?) .
Remarks.—The Marginotruncanidae, n. fam., represent
a phylogenetic link between the Rotaliporidae and Globo-
truncanidae. They differ from the Rotaliporidae (1) by
showing larger portici with infralaminal accessory aper-
tures; (2) by having a primary aperture which is usually
more umbilical in position; and (3) by frequently showing
well-developed double keels. The Marginotruncanidae dif-
fer from the Globotruncanidae (1) by having large portici
with infralaminal accessory apertures, but lacking intrala-
minal accessory apertures and (2) by having a primary
aperture which is extraumbilical-umbilical in position.
The Marginotruncanidae thus seem to share some fea-
tures in common with both the Globotruncanidae and the
Rotaliporidae. The possession of double keels among most
species of Marginotruncana is certainly a elobotruncanid
feature whereas the extraumbilical-umbilical position of
the aperture is definitely a rotaliporid characteristic. Hence,
the writer believes that the Marginotruncanidae evolved
from the Rotaliporidae and in turn gave rise to the Globo-
truncanidae (Text-figure 6). It is likely that Whiteinella
Pessagno, n. genus arose from a Hedbergella stock via the
enlargement of the portici, the acquisition of infralaminal
accessory apertures, and the migration of the primary aper-
ture to a more umbilical position. Whiteinella Pessagno,
n. genus gave rise to Marginotruncana Hofker through the
acquisition of an imperforate peripheral band and single
or double keels. The globotruncanid genus Archaeoglobi-
gerina Pessagno, n. gen. probably evolved directly from
Whiteinella via (1) the migration of the primary aperture
to a true umbilical position and (2) by the enlargement of
the portici and acquisition of intralaminal accessory aper-
tures to form true tegilla. The writer believes that Globo-
truncana s.s. evolved from a Archaeoglobigerina Pessagno,
n. gen. ancestor although there is certainly some evidence
to suggest that certain species of Globotruncana evolved
directly from species of Marginotruncana.
Range.—Turonian—Santonian.
Occurrence.—Upper Cretaceous strata; world-wide.
WHITEINELLA Pessagno, new genus
Type species—Whiteinella archaeocretacea Pessagno,
n. sp.
Description.—Test low trochospiral coil with shallow
umbilicus; lacking carinae, but often having imperforate
peripheral bands; primary aperture extraumbilical-umbili-
cal in position often nearly umbilical with large portici;
portict having infralaminal accessory apertures situated
near suture contacts, but lacking intralaminal accessory
apertures. Outer wall radial hyaline perforate; septal wall
microgranular hyaline, perforate; portici microgranular
hyaline, perforate (?) .
Remarks.—Whiteinella Pessagno, new genus differs
from Marginotruncana Hotker by lacking single or double
carinae. It differs from Hedbergella by possessing much
larger portici and by the more umbilical position of the
primary aperture,
It is likely that Globigerina holzli Hagn and Zeil (1954,
pp. 51-52, pl. 2, figs. 8a-c) should be included under
Whiteinella, new genus. Likewise, Ticinella aprica Loe-
blich and ‘Tappan (1961, p. 294, pl. 4, figs. 15, 16a-c; 214)
from the Turonian (not Cenomanian as stated by Loeblich
and ‘Tappan, 1961) Arcadia Park formation should be as-
signed to Whiteinella, new genus instead of Ticinella as it
lacks sutural supplementary apertures umbilically. The um-
bilical view of the holotype (TI. aprica Loeblich and ‘Tap-
pan, pl. 4, fig. 16b) clearly shows the large portici with in-
fralaminal supplementary apertures characteristic of White-
nella, n. gen., and indeed of all well-preserved Margino-
truncanidae. The primary aperture of 7. aprica Loeblich
and Tappan is described as being extraumbilical-umbilical
in position oriented somewhat toward the plane of coiling.
It is also possible that T. aprica Loeblich and Tappan is a
junior synonym of G. holzli Hagn and Zeil.
Whiteinella, n. gen. is named for the late Maynard P.
White in honor of his early contribution to the Upper Cre-
taceous and Lower Tertiary stratigraphy of the Tampico
area of Mexico.
Range.—M. helvetica assemblage zone to G. bulloides
assemblage zone. Turonian to Santonian.
Occurrence.—Upper Cretaceous of Texas, Mexico, and
Trinidad in so far as definitely known.
Whiteinella archaeocretacea Pessagno, n. sp.
Plate 51, figures 2-4; Plate 54, figures 19-21, 22-24, 25;
Plate 100, figure 8
Description.—Test lobulate, coiled in low trochospiral
|
|
|
GuLre CRETACEOUS FORAMINIFERA: PESSAGNO 299
coil with four to five chambers in last whorl. Chambers
spherical, initially; becoming ovate in cross-section in last
whorl; in spiral and umbilical views, chambers broad in last
whorl; separated by slightly curved to straight, depressed,
radial sutures. Test with three whorls of chambers increas-
ing rapidly in size; chambers of early whorl small in com-
parison to those of last whorl. Surface of test coarsely rugose
in well-preserved specimens. Umbilicus shallow and wide.
Primary aperture extraumbilical-umbilical to nearly umbi-
lical in position with large portici when well preserved.
Outer wall radial hyaline perforate; septal wall microgranu-
lar hyaline perforate; portici microgranular hyaline, per-
forate (?).
Remarks.—Whiteinella archacocretacea Pessagno, n. sp.
is closely related to Whiteinella inornata (Bolli), but dif-
fers from the latter species by having a rounded rather than
an angled periphery.
Type locality—TX 105: Black calcareous shale of the
Eagle Ford group (South Bosque formation) ; eight feet
below the contact between the Eagle Ford group and the
Austin chalk; Bouldin Creek about 280 yards down the
Missouri Pacific Railroad tracks east of Mary Street cross-
ing. Austin, Travis County, Texas.
Deposition of types—The holotype and figured para-
types of Whiteinella archaeocretacea Pessagno will be de-
posited in the collections of the U.S. National Museum,
Washington, D.C. Unfigured paratypes will be deposited
in the collection of the Paleontological Research Institu-
tion, Ithaca, New York.
Range.—M. helvetica assemblage zone, M. sigali sub-
zone to M. renzi assemblage zone. ? G. bulloides assemblage
zone, ? M. concavata subzone.
Occurrence.—_In Mexico JW. archaeocretacea has been
observed in the Agua Nueva formation (Turonian) at
Peregrina Canyon northwest of Ciudad Victoria and in the
Turonian portion of the San Felipe formation at Boca
Canyon south of Monterrey (Text-figure 2). In Texas IV.
archaeocretacea occurs throughout the Turonian portion
of the Eagle Ford group at Dallas, Waco, Austin, Del Rio,
Langtry, and Chispa Summit (Text-figure 2). At TX 105,
its type locality, W. archaeocretacea occurs with Margino-
truncana helvetica (Bolli), M. sigali (Reichel), M. mar-
ginata (Reuss), M. bouldinensis Pessagno, n. sp., Hetero-
helix reusst (Cushman), Clavihedbergella simplex (Mor-
row) , Hedbergella delrioensis (Carsey), H. amabilis Loe-
blich and Tappan, and Whiteinella inornata (Boll) .
Whiteinella inornata (Bolli)
Plate 71, figures 3-5; Plate 100, figure 5
1957. Globotruncana inornata Bolli, U.S. Nat. Mus., Bull., No. 215,
pp- 57, 58, pl. 13, figs. 5a-6c.
1962. Not Globotruncana (Globotruncana) inornata Bolli, Pessagno,
Micropaleont., vol. 8, No. 3, p. 362, plate 6, figures 7-9.
Remarks.—As_ noted previously, Whiteinella inornata
(Bolli) is closely related to Whiteinella archaecretacea
Pessagno, n. sp. and differs from the latter species only by
possessing an angled periphery. Bolli (in Bolli, et al., 1957,
p. 57) noted that this species has a faint peripheral keel and
has a primary aperture in an umbilical position. However,
the writer has noted no true carinae or umbilical primary
apertures in the examination of Bolli’s types at the U.S.
National Museum or on the specimens encountered during
the course of this study. Sections made of specimens of JV.
imornata indicate usually that its periphery is radial
hyaline perforate and lacks an imperforate peripheral band.
W. inornata (Bolli) seems to have evolved from W.
archaeocretacea, n. sp. through the acquistion of a markedly
angled periphery. W. inornata itself seems to have given
rise to Marginotruncana indica (Jacob and Sastry) through
the acquisition of a double keel.
Range.—M. helvetica assemblage zone, M. sigali sub-
zone to M. renzi assemblage zone. ? G. bulloides assemblage
zone, ? M. concavata subzone.
Occurrence.—W. inornata occurs in the Turonian part
of the San Felipe formation of Mexico as exposed at Boca
Canyon south of Monterrey. It also occurs in the Turonian
portion of the Eagle Ford group of Texas (Text-figure 2) .
Turonian and Coniacian of Trinidad.
Genus MARGINOTRUNCANA Hofker, 1956
Type species——Rosalina marginata Reuss, 1845.2
1956. Marginotruncana Hofker, Neues Jahrb. Geol. Palaeont., Abh.
103, pp. 319-320.
1957. Helvetoglobotruncana Reiss. Contr. Cushman Found. Foram.
Res., vol. 8, pt. 4, pp. 136, 137, text-figs. 5i and 7m.
Emended definition —Test trochospiral with well-de-
veloped single or double keels; chambers angular truncate,
angular rhomboid, or hemispherical; umbilicus usually
shallow. Primary aperture extraumbilical-umbilical to
nearly umbilical in position, often highly arched; tending
to migrate toward the plane of coiling. Well-preserved speci-
mens having large portici with infralaminal accessory sup-
plementary apertures adjacent to suture contacts with por-
tici. Outer wall radial hyaline perforate except for keels
which are radial hyaline imperforate and ornamental fea-
tures such as rugosities which are ultragranular hyaline
imperforate. Septal walls microgranular hyaline, perforate;
portici microgranular hyaline perforate (?) .
“See footnote (@) page 307.
300 PALAEKONTOGRAPHICA AMERICANA (V, 37)
Remarks.—Marginotruncana differs from Globotrun-
cana s.s. (1) by having a primary aperture which is ex-
traumbilical-umbilical in position; (2) by lacking true te-
gilla with intralaminal supplementary apertures; and (3)
by having a much shallower and wider umbilicus.
As noted by Bolli, et al., (1957, p. 45), Hofker (1956,
p. 319) considered Globotruncana s.s.—‘to have a strongly
reduced protoforamen (primary aperture) , which is no
longer an open slit, and Marginotruncana was said to have
lost the protoforamen or to have it fused with a deutero-
foramen (secondary aperture). The diagrammatic figures in
his text-figure | are highly misleading, as there are not two
openings in the final chamber of true Globotruncana, and
there is no extraumbilical opening into the chamber.”
It seems obvious to the writer after examining Hofker’s
(ibid.) text-figures 1 and 2 that Hofker’s term protofora-
men is not equivalent to the term primary aperture of Bolli,
et al. (ibid.) but is actually equivalent to the term second-
ary aperture (infralaminal accessory aperture) of these lat-
ter authors. Furthermore, Hofker’s term deuteroforamen 1s
equivalent to the term primary aperture of Bolli, et al.,
(ibid.) (cf. Hofker, ibid., text-figure 2). Hofker seemed to
have been misled by the alternation of the shape of the
primary aperture by portici. His greatly reduced protofora-
men is nothing more than an infralaminal accessory aper-
ture at the edge of the porticus near its junction with the
chamber wall.
Bolli, et al. (1957, p. 46) also criticized Hofker for com-
pletely disregarding Reuss’s (1845) original description of
Rosalina marginata Reuss by figuring a single-keeled form
with an extraumbilical-umbilical primary aperture. In de-
fense of Hofker, it should be pointed out that he does fig-
ure a double-keeled specimen in text-figure 2 and in text-
figure 7. However, the specimen figured in text-figure 6
is questionably single-keeled and the specimen figured in
figure 8 is definitely single-keeled. All of the specimens of
M. marginata (Reuss) figured herein are double-keeled
and do possess (as indicated by Hofker) extraumbilical-
umbilical apertures.
A number of the species assigned by Hofker to Mar-
ginotruncana are assignable (via the emended definition
herein) to Globotruncana s.s., Praeglobotruncana, Globo-
truncanella, and Abathomphalus. These will be indicated
in synonomies elsewhere in this monograph.
In summary, Marginotruncana Hofker is not regarded
as a junior synonym of Globotruncana as indicated by Bolli,
et al., (1957, p. 46), but is a distinct and valid genus having
important phylogenetic significance in the evolution of
Upper Cretaceous planktonic Foraminifera.
Range.—M. helvetica assemblage zone, M. sigali sub-
zone to G. bulloides assemblage zone, M. concavata subzone.
Occurrence.—Upper Cretaceous; world-wide
Marginotruncana angusticarenata (Gandolfi)
Plate 65, figures 14-19; Plate 98, figures 5, 9-11
1936. Globotruncana appenninica—linnei Renz (part), Eclogae Geol.
Helv., vol. 29, No. 1, pl. 6, figs. 17, 20; not figs. 16, 21-26; pl. 8,
fig. 2; not figs. 3, 5.
1942. Globotruncana linnei (d’Orbigny) var. angusticarenala Gan-
dolfi, Riv. Ital. Pal., ann, 48, mem. 4, pp. 126, 150, 153; pl. 4,
figs. 17, 30, text-figure 46 (figs. 3a-c) .
1942. Globotruncana renzi Gandolfi (part), Riv. Ital. Pal., Ann. 48,
mem. 4, p. 124, pl. 3, figs. la-c; pl. 4, figs. 16, 28, 29; not fig.
15; pl. 10, fig. 2; not text-figs. 45a-c.
1945. Globotruncana lapparenti coronata Bolli (part), Eclogae Geol.
Helv., vol. 37, No. 2, p. 233, pl. 9, fig. 14, not fig. 15; not text-
fig. 1: nos, 21-22.
1954. Globotruncana lapparenti Brotzen angusticarenala Gandolfi,
Hagn and Zeil, Eclogae Geol. Helv., vol. 47, No. 1, pp. 44, 45,
pl. 7, figs. 9, 10.
1954. Globotruncana lapparenti Brotzen coronata Bolli, Hagn and
Zeil, Eclogae Geol. Helv., vol. 47, No. 1, pp. 43, 44, not pl. 3, figs.
3a-c; pl. 7, figs. 1-2, not fig. 3.
1954. ?Globotruncana lapparenti Brotzen bulloides Vogler, Hagn and
Zeil, Eclogae Geol. Helv., vol. 47. No. 1 pp. 45, 46. pl. 2. figs.
5a-c; pl. 7, fig. 4.
1957. Globotruncana angusticarenata Gandolfi, Sacal and Debourle
(part) , Soc. Géol. France, n. sér., Mém. No. 78, pl. 27, figs. 2, 4;
not figs. 23, 24.
1957. Globotruncana (Globotruncana) coldreriensis Gandolfi, Contr.,
Cushman Found. Foram. Res., vol. 8, pt. 2, p. 64, figs. 7a-c.
1960. Globotruncana renzi Gandolfi, Trujillo (part), Jour. Paleont.,
vol. 34, No. 2, p. 343, pl. 50, figs. 3a-c; not 4a-c.
1960. Globoltruncana angusticarenata Gandolfi, Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 821, pl. 7, figs. 3a-c.
1960. Globotruncana lapparenti lapparenti Brotzen, Klaus, Eclogae
Geol. Helv., vol. 52, No. 2, p. 822, pl. 8, figs. 2a-c.
1960. Globotruncana cf. lapparenti coronata Bolli, Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 821, pl. 7, figs. 4a-c.
1960. Globotruncana arca (Cushman), Klaus, Eclogae Geol. Helv., vol.
52, No. 2, p. 824, pl. 7, figs. 5a-c.
1960. Globotruncana fornicata Plummer, Klaus, Eclogae Geol. Helv.,
vol. 52, No. 2, p. 825, pl. 8, figs. 4a-c.
1963. Globotruncana (Globotruncana) renzi renzi Gandolfi, Van
Hinte, Jahrb. Geol. Bund, Sond. 8, p. 66, pl. 2, figs. la-c; 2a-c.
Description.— Vest trochospiral, spiroconvex with nar-
row double keel following peripheral margin. Primary aper-
ture extvaumbilical-umbilical to nearly umbilical in’ posi-
tion with well-developed portici when well preserved. Five
to eight chambers in last whorl, petaloid to enlongate spir-
ally. Sutures separating chambers both spirally and um-
bilically curved, slightly raised. Outer wall radial hyaline
perforate except for double keel which is radial hyaline
imperforate. Septal walls microgranular hyaline, perforate.
Portici microgranular hyaline, perforate (?) .
Remarks.—Gandolfi (1942, pp. 126, 150, 153) originally
erected this species in syntypic series. The specimen repre-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 201
sented by text-figure 46 (figs. 3a-c) is designated the lecto-
type of G. angusticarenata herein. In addition, the speci-
mens illustrated by Gandolfi in plate 4 (figs. 17 and 30)
are designated paralectotypes of G. angusticarenata.
M. angusticarenata differs from M. marginata (Reuss)
by the curved nature of its sutures both spirally and um-
bilically and by the possession of more numerous chambers
in the last whorl. It is likely that M. angusticarenata evolved
from M. marginata. Transitional forms have been observed
in the Eagle Ford group of ‘Texas.
Dalbiez (1955, p. 165) correctly noted that one of
Gandolfi’s syntypes (pl. 3, figs. la-c) of Globotruncana
renzi ‘“—differs from Gilt. lapparenti angusticarenata only in
the reduced number of chambers in the last whorl (there
are five instead of seven)’. Likewise, it should be noted
that the specimens figured by Gandolfi (ibid.) in plate 4
(figs. 16, 28, 29) and in plate 10 (fig. 2) are assignable to
M. angusticarenata. Only the specimens figured in plate 4,
figure 15 and in text-figures 45a-c are considered M. renzi
(Gandolfi) herein. The specimen figured in text-figures
45a-c has been selected as the lectotype of Globotruncana
renzi Gandolfi (See M. renzt) .
The writer likewise feels that the specimen figured by
Bolli (1945, pl. 9, fig. 14) as a syntype of Globotruncana
coronata Bolli should be referred to M. angusticarenata
(Gandolfi) .
Gandolfi in 1957, hoping to clarify the troubled taxo-
nomic status of Globotruncana renzi Gandolfi, selected fig-
ures la-c (pl. 3) among the syntypes of Globotruncana renzi
as the holotype of a new species, Globotruncana (G.)
coldreriensis Gandolfi, As noted above, the form figured in
figures la-c is assignable to M. angusticarenata (Gandolfi) .
Hence, G. (G.) coldreriensis becomes a junior synonym of
M. angusticarenata.
Form analysis measurements of M. angusticarenata are
presented in Text-figure 18.
Range.—M. helvetica assemblage zone, IW. archacocre-
tacea subzone to G. bulloides assemblage zone, M. concavata
subzone.
Occurrence.—In Mexico this species has been found
throughout the Coniacian and Lower Santonian parts of
the San Felipe formation (Text-figure 2). In Texas M.
angusticarenata is common in the Turonian portion of the
Eagle Ford group. It has been observed in the South Bosque
formation at Austin and Waco and in the Boquillas for-
mation in Terrell and Val Verde Counties (Sycamore
Creek near Del Rio and Lozier Canyon near Langtry, cf.
Text-figure 2). M. angusticarenata occurs in the Coniacian
and Lower Santonian portions of the Austin chalk in
TEXT-FIGURE 18
Marginotruncana
ticarenata
-493]0.280]0.205]0.
0.070] 0. 0.070 0.
Double keel
arly stage
All measurements in millimeters
+ = double keeled early stage present
Large portici can be observed on this specimen They do not extend across the whole
umbilicus as do true tegillae, but extend just short of half way.
lapparenti coronata (Bolli) Hagn and Zeil (1954, pl. 7, fig. 1-2)
coronata Bolli, 1945
Val Verde and Travis Counties and in the Lower San-
tonian portion of the Austin chalk in McLennan and
Dallas Counties (cf. Text-figure 2) .
M. angusticarenata was originally described by Gan-
dolfi from the Turonian of Switzerland. It also occurs in
Italy, Bavaria, California, and ‘Trinidad.
Marginotruncana bouldinensis Pessagno, n. sp.
Plate 54, figures 13-15; Plate 56, figures 4-6; 7-9; Plate 98,
figure 1
Description.—Test trochospiral, spiroconvex, with four
or five chambers in last whorl. Chambers of spiral side
crescent-shaped, individually somewhat planiform; earlier
chambers somewhat rugose; sutures curved, raised, often
beaded. Umbilical side of test slightly concave with rugo-
sities sometimes present on first one or two chambers of last
whorl; sutures radial, straight to slightly curved; chambers
wedge-shaped; predominately depressed. Umbilicus shallow
and broad though somewhat variable in size. Periphery
with double keel which seems to be better developed pos-
teriorly than anteriorly. Primary aperture extraumbilical-
5()2 PALAEKONTOGRAPHICA AMERICANA
umbilical in position. Portici with infralaminal accessory
apertures on well-preserved specimens. Outer wall radial
hyaline, perforate except for double keel which is radial
hyaline imperforate. Septal wall microgranular hyaline,
Portici perforate (?) .
T’X/TX value rather low; averaging about 0.30 in four
perforate. microgranular hyaline
sectioned paratypes. (Text-figure 19).
Remarks.—Marginotruncana bouldinensis — Pessagno,
n. sp. differs from Marginotruncana marginata (Reuss) (1)
by its much lower T’X/TX value; (2) by the thinner and
more compressed nature of its test as measured along line
T-T’; and (3) by the flattened nature of its chambers
spirally and umbilically. It probably evolved from JWhite-
archaeocretacea Pessagno, n. sp. by obtaining a
double keel and obtaining flattened chambers spirally and
umbilically.
M. bouldinensis is named after Bouldin Creek, Aus-
inella
tin, Travis County, Texas.
Type locality.—The
bouldinensis Pessagno, n. sp. is from TX 105. Black cal-
holotype of Marginotruncana
careous shale; Eagle Ford group; South Bosque formation;
eight feet below the contact between the Eagle Ford group
and Austin chalk. Bouldin Creek east of Mary Street; about
280 yards down Missouri Pacific Railroad tracks east of
Mary Street Crossing; Austin, Travis County, ‘Texas.
The figured paratypes are from TX 105 and from TX
353: Eagle Ford group, South Bosque formation. Gray
brown, laminated massive calcareous mudstone with
abundant light gray aphanitic limestone laminae. Socony
Mobil Research Lab.; Waco Core of Eagle Ford group:
156 feet. (See Brown and Pierce, 1962, A.A.P.G.,
No. 12, pp. 2133-2147) .
Range.—M. helvetica assemblage zone, |W.
vol. 46,
archaecocre-
tacea subzone in so far as known from this study.
Occurrence.—In Texas M. bouldinensis occurs in the
Turonian portion of the Eagle Ford group: South Bosque
formation (Travis and McLennan Counties) and the Brit-
(Dallas County) (cf. Text-
ton formation (upper part)
figure 2).
Marginotruncana canaliculata (Reuss)
Plate 74, figures 5-8
1854. Rosalina canaliculata Reuss, K. Akad. Wiss. Wien, Math.—Natur.
K1., Denkschr., Bd. 7, p. 70, pl. 26, figs. 4a-b.
1960. Globotruncana canaliculata (Reuss), Trujillo,
vol. 34, No. 2, p. 341, pl. 50, figs. la-c.
Jour. Paleont.,
Description.—Test trochospiral, flattened spirally and
double keel.
Chambers arranged in two to two and one-half whorls;
umbilically; periphery truncated by wide
usually six to seven chambers in final whorl. Chambers
Mar ginotruncana
bouldinensis
PE 977
DXeLOS
lex
Angle XD
Ht. double
keel at D
ity.
keel at D'
All measurements in millimeters.
in final whorl crescent-shaped to petaloid spirally, but
distinctly wedge-shaped umbilically. Sutures on spiral side
curved, slightly raised, usually not beaded; sutures on um-
bilical side straight, radial, depressed. Umbilical side of
test often with coarse, beadlike, rugosities on chamber sur-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 303
faces. Stout portici with infralaminal accessory apertures
extending out into a small umbilicus. Primary aperture in-
teriomarginal, extraumbilical in position, a slightly arched
opening. Outer wall radial hyaline perforate except for
double keel which is radial hyaline imperforate. Septal
walls microgranular hyaline sparsely perforate. Portici mi-
crogranular hyaline probably sparsely perforate.
Remarks.—M. canaliculata (Reuss) has been one of
the most frequently misidentified species of planktonic
Foraminifera in the Upper Cretaceous (see synonomies of
Globotruncana linneiana (d’Orbigny) and Globotruncana
lapparenti s.s. Brotzen) and has long served as a “waste
basket” term for a number of double keeled species of
Globotruncana and Marginotruncana.
The problem of the specific identity of Rosalina cana-
liculata Reuss is made complex by virtue of the fact that
Reuss (1854, pl. 26, figs. 4a-b) only figured spiral and
umbilical views of his type specimen and by virtue of the
fact that the depository of Reuss’s type specimen is un-
known after a period of over 110 years. It seems probable
that Reuss’s type specimen of R. canaliculata is lost.
From Reuss’s descriptions (see Trujillo, 1961, p. 341)
and figures it can be established that R. canaliculata pos-
sesses (1) a wide double keel; (2) petaloid to crescent-
shaped chambers spirally; (3) a small umbilicus; and (4)
wedged-shaped chambers umbilically.
To alleviate the taxonomic chaos surrounding this
species, a neotype (PI. 74, figs. 5-8 herein) has been selected
from the lower part of the Gosau beds of Edelbachgraben,
Austria. Two samples from the lower part of the Gosau se-
quence were examined. One sample (G-19) (from W. W.
Hay, Dept. Geology, University of Ilinois) contains a well-
preserved fauna in marls of Late Coniacian or Early San-
tonian age from Gosautal, Edelbachgraben. ‘The following
species were noted at this locality:
Marginotruncana (Reuss) —abundant;
M. marginata (Reuss) —abundant; M. concavata (Brotzen)
—rare; Globotruncana lapparenti s.s. Brotzen—common;
canaliculata
Marginotruncana coronata (Bolli)—common; M. pseudo-
linneiana Pessagno, n. sp.—abundant.
The second sample (from Ruth ‘Todd, U.S. Geol.
Survey, Washington, D.C.) is from the type locality of
Cythere sphenoides Reuss and contains a poorly preserved
fauna in marls of Late Coniacian or Early Santonian age.
It contains the same assemblage as cited above, but G. lap-
parenti is absent and M. canaliculata is rare. This locality
occurs in marls in the lower part of the Gosau sequence and
is undoubtedly the same horizon mentioned by Reuss
(1854, pp. 7-8). Reuss (¢bid.) noted that the marls of the
lower Gosau beds are rich in ostracods and Foraminifera.
His faunal lists (pp. 7, 8) include Cythere sphenoides
Reuss, Rosalina canaliculata Reuss, Rosalina marginata
Reuss and other species of Foraminifera and ostracods. As
samples from both localities mentioned above include the
same planktonic assemblage, it is likely that they came
from about the same stratigraphic horizon in the lower part
of the Gosau beds. Hagn (1957, p. 67) indicated that the
Lower and Middle Gosau beds are of Coniacan to Early
Campanian age whereas the Upper Gosau is of Late Cam-
panian age. Inasmuch as the first sample (G-19) noted
above contains the best preserved material, a neotype® is
selected from this sample.
M. canaliculata (Reuss) differs from M. bouldinensis
Pessagno, n. sp. by possessing a wider double keel which
tends to increase in width during the ontogeny of the indi-
vidual. The double keel of M. bouldinensis is narrower and
is absent on the anterior portion of the test. Furthermore,
M. bouldinensis is concave umbilically and is spiroconvex
whereas M. canaliculata is nearly biconvex.
In thin-section M. canaliculata is difficult to differen-
tiate from G. lapparenti Brotzen. It differs from the latter
species, however, by possessing a more weakly developed
double keel which is completely radial hyaline, imperforate
rather than both radial hyaline, and ultragranular hyaline,
imperforate.
M. canaliculata (Reuss) differs from M. marginata
(Reuss) largely by possessing a thicker double keel, a
planiform test both spirally and umbilically, and a more
lowly arched extraumbilical aperture. It differs from M.
coronata (Bolli) by having a smaller umbilicus and by
possessing wedge-shaped chambers umbilically separated by
straight, radial, depressed sutures.
Deposition of types—The neotype and topotypes of
R. canaliculata (Reuss) will be deposited in the collections
of the U.S. National Museum, Washington, D.C.
Type locality.—Gosautal, Edelbachgraben, Austria.
Marl sample from the lower Gosau beds. Locality G-19 of
W. W. Hay (see Appendix) .
Range.—M. helvetica assemblage zone, W. archaeocre-
tacea subzone to G. bulloides assemblage zone, M. concavata
subzone insofar as known in this study.
Occurrence.—M. canaliculata was not recognized in
Gulf Coast samples until late in the present study. How-
ever, in Texas it definitely occurs in the Late Turonian
part of the Chispa Summit formation (Eagle Ford group)
3For selection of neotype see Article 75, a-f, p. 83, Internat. Code
Zool. Nomen., 1961—Ed.
304 PALAEONTOGRAPHICA AMERICANA (V, 37)
at Chispa Summit in Jeff Davis County and in the Late
Turonian South Bosque formation at Bouldin Creek in
Travis County. It occurs in the Coniacian (M. renzi assemb-
lage zone) part of the basal Austin chalk at Sycamore Creek
in Val Verde County; in the Early Santonian (M. conca-
vata subzone) part of the Austin chalk at Cow Creek in
Kinney County; at White Rock Creek in McLennan Coun-
ty; and in Dallas, Dallas County (Text-figures 1, Zein
Mexico M. canaliculata (Reuss) has been observed in the
Late Turonian and Coniacian portions of the San Felipe
formation at Boca Canyon near Monterrey and in the early
Santonian portion of the San Felipe formation at Mamu-
lique Pass (Rt. 85, Mexico, D.F.—N. Laredo Highway) .
The writer has recently observed M. canaliculata Reuss
in the lower part of the Funks formation of Yolo County,
California. Associated planktonic Foraminifera and ammon-
ites (Protexanites thompsoni Jones) appear to indicate that
the lower portion of the Funks is of Coniacian or perhaps
Early Santonian age. The specimens described and the
specimen figured by Trujillo (1960) from the Coniacian of
the Redding area, Shasta County, California, seem to be
referrable to this speces.
Although there are numerous references to this species
in the European literature, most of these prove assignable to
other species. In Europe this species is only known at
present from its type locality in Austria.
Marginotruncana concavata (Brotzen)
Plate 58, figures 1-9; Plate 95, figures 6,7; Plate 99, figures 1, 3
1934. Rotalia concavata Brotzen, Deutsch. Ver. Palastinas, Zeitschr.,
vol. 57, p. 66, pl. 3, fig. b.
1941. Globotruncana linnei d’Orbigny subsp. pendens Vogler (part) ,
Paleontographica, Suppl. Bd. 4, Abt. 4, p. 287, pl. 24, figs. 4-6,
not figs. 1 and 7, ? figs. 2, 3.
1950. Globotruncana ventricosa White, Mornod, Eclogae Geol. Helv.,
vol. 42, No. 2, p. 591, text-fig. 12: la-c; 2a-c.
1952. Globotruncana asymetrica Sigal, 19th Congr. Géol. Internat.,
Monogr. Rég., Alger, ser. 1, No. 26, p. 35, text-fig. 35 (3 figs.
p- 34).
1953. Globotruncana aff. concavata (Brotzen), de Klasz, Geol. Bay-
arica, No. 17, pp. 236, 237, pl. 6, figs. 2a-c.
1953. Globotruncana fundiconulosa Subbotina (part), Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p.
200) spl 4: figs. la-c (holotype), 2a-c, 3a-c; not 4a-c (—G.
ventricosa White) .
1955. Globotruncana (Globotruncana) ventricosa ventricosa White,
Dalbiez, Micropaleont., vol. 1, No. 2, p. 168, text-figs. 7a-d.
1955. Globotruncana (Globotruncana) ventricosa carinata Dalbiez,
Micropaleont., vol. 1, No. 2, pp. 168, 169, text-figs. 8a-c.
1957. Globotruncana concavata (Brotzen), Bolli, in Bolli, et al., U.S.
Nat. Mus., Bull., No. 215, p. 57, pl. 13, figs. 3a-c.
1960. Not Praeglobotruncana concavata (Brotzen), Klaus, Eclogae
Geol. Helv., vol. 52, No. 2, p. 797, pl. 7, figs. 2a-c (called P. con-
cavata transitional to P. (?) ventricosa in plate description).
1960. Globotruncana ventricosa ventricosa White, Tollmann, Jahrb.
Geol. Bund., Bd. 103, pp. 195-196, pl. 21, figs. 7a-c. :
1962. Not Globotruncana concavata (Brotzen), Herm, Bayer. Akad
Wiss. Math.-Nat. KI., Abh., n. ser., No. 104, pp. 70, 71, pl. 5, fig.
4.
1962. Globotruncana concavata (Brotzen) , Barr, Paleontology, vol. 4,
pt. 4, p. 569, pl. 71, figs. 4a-c.
Remarks.—Marginotruncana concavata (Brotzen) has
been confused by various workers with Globotruncana
ventricosa (White). It differs from G. ventricosa: (1) by
having a pronounced extraumbilical-umbilical aperture; (2)
usually more convex umbilically and planiform (often
concave) spirally thus having a higher T’X/TX value; (3)
usually having a narrower double keel in the last whorl;
(4) by always having a D,-D’,/D,-D’, value exceeding 2.1;
(5) by having chambers that slope toward umbilicus; and
(6) by displaying a Whiteinella inornata (Boll) nepionic
stage.
Many workers such as Bolli (1957, p. 57) have inferred
that M. concavata (Brotzen) and G. ventricosa White are
phylogenetically related. However, the presence of an ex-
traumbilical aperture, portici, and the lack of true tegilla
clearly place the former species in the Marginotruncanidae,
new family. Furthermore, whereas M. concavata shows a
WW. inornata nepionic stage (Pl. 95, figs. 6-7; Pl. 99, fig. 1),
G. ventricosa shows a G. linneiana (d’Orbigny) nepionic
stage (cf. 95, figs. 10, 11). Thus, M. concavata is not
only unrelated to G. ventricosa at the family level, but it is
also unrelated to G. ventricosa at the species level. As noted
by Bolli (1957, p. 57), the range zones of these species are
distinctly different. Although M. concavata and G. ventri-
cosa are grossly similar and appear homeomorphic, this
similarity proves superficial when studied in detail.
Form analysis measurements of sectioned free specimens
of M. concavata are presented in Text-figure 20. Text-figure
61 is a scatter plot of T’X/TX and D,-D’,/D,-D’, for M.
concavata and G. ventricosa.4
Globotruncana asymetrica Sigal (1952) and Globotrun-
cana (Globotruncana) ventricosa carinata Dalbiez (1955)
are regarded as junior synonym of Marginotruncana con-
cavata (Brotzen) .
The holotype (figs. la-c) and two paratypes (figs. 2a-c;
3a-c) of G. fundiconulosa Subbotina (1953) are assignable
to M. concavata (Brotzen) . These specimens all show (1)
extraumbilical apertures; (2) large portici; (3) chambers
abruptly sloping toward the umbilicus; (4) narrow double
keels; and (5) D’,-D,/D’,-D,, values ranging from 2.1 to
2.25. Large portici for M. concavata have also been illus-
trated by Barr (1962).
Range.—M. renzi assemblage zone (upper part) to G.
bulloides assemblage zone: M. concavata subzone.
41),-D’,— Diameter of final whorl.
D,-D’,=Diameter of next to last whorl.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 305
Occurrence.—M. concavata has been observed in Mex-
ico during this study in the Santonian portion of the San
Felipe formation as exposed (1) in the Sierra Madre Orien-
tal along Route 80 west of Antiguo Morelos (Tamaulipas)
and east of Ciudad del Majz (San Luis Potosi) ; (2) in the
Sierra Madre Oriental at Peregrina Canyon northwest of
Ciudad Victoria; (3) at Boca Canyon south of Monterrey;
and (4) at Mamulique Pass along the Mexico, D.F.—
Nuevo Laredo Highway (Rt. 85). In Texas M. concavata
has been observed in the Austin chalk: (1) in the “Atco”
member exposed at Pinto Creek. and Cow Creek in Kin-
ney County; (2) in the Dessau and Burditt members in
Travis County; (3) throughout the “Atco” and “Bruce-
ville’ members in McLennan County; and (4) throughout
the “Atco”, “Bruceville’, and the “Hutchins” members in
Dallas County. The Pinto Creek occurrence is Coniacian.
The other occurrences are Early Santonian.
Bolli recorded this species from the Lower Santonian of
Trinidad. It is known from the Santonian of France,
Switzerland, Israel, Tunisia, Algeria, Bavaria, the Isle of
Wight, Gabon, and Madagascar. It is noteworthy that in
Madagascar, Collignon (1959, p. 49; Table IV) recorded M.
concavata in his lower-most ammonite zone for the Santon-
ian:—the Texanites oliveti zone. De Klasz (1961, p. 123)
and Barr (1962
cies occurs in Coniacian strata. De Klasz argued for an ex-
, p. 569 and text-fig. 2) noted that this spe-
tension of the range zone of M. concavata into the Conia-
cian of Gabon (equatorial Africa) in that it is associated
with Coniacian ammonites such as Peroniceras dravidicum
Kossmat, Gauthiericeras marge Schult, and Barroisceras
haberfellnert Von Hauer.
Marginotruncana coronata (Bolli)
Plate 65, figures 11-13; Plate 100, figure 6
1945. Globotruncana lapparenti Brotzen subsp. coronata Bolli, mclogae
Geol. Helv. vol: 37, No. 2; p. 233, text-fig. I; 21, 22; pl. 9) fig,
15, not fig. 14.
1950. Globotruncana lapparenti coronata Bolli, Mornod, Eclogae Geol.
Helv., vol. 42, No. 2, p. 591, text-fig. 13: a-c.
1953. Globotruncana coronata Bolli, Subbotina, Trudy, Vses. Neft.
Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 180, pl.
8, figs. la-c.
1953. Globotruncana lapparenti Brotzen, Subbotina, Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p.
178, pl. 7, figs. la-c; 3a-c; 5a-c; not 2a-c, 4a-c.
1954. Globotruncana lapparenti coronata Bolli, Hagn and Zeil, Eclogae
Geol. Helv., vol. 47, No. 1, pp. 43, 44, pl. 3,
fig. 3; not figs. 1, 2.
1957. Not Globotruncana cf. lapparenti coronata Bolli, Bolli, U.S. Nat.
Mus., Bull., No. 215, pl. 14, figs. 2a-c.
1960. Not Globotruncana &. lapparenti coronata Bolli, Klaus, Eclo-
gae Geol. Helv., vol. No. 2, p. 821, pl. , figs. 4a-c.
1960. Globotruncana eee, (d’Orbigny) , Trujillo, Jour. Paleont.,
vol. 34, No. 2, pp. 342, 343, pl. 49, figs. 8a-c.
figs. 4a, b; pl. 7,
TEXT-FIGURE 20
Marginotruncana
concavata
(Brotzen)
UK Tunisia
PE 837 *%*
PE 1038
6.
205 10.196 hab. 168
.056 10.056 Rael
Ht. double
keel at D
—————
All measurements in millimeters.
* De = Diameter of last whorl. D,-D', = Diameter of next to last whorl.
* From Bolli.
1960. Globotruncana coronata (Bolli) , Tollmann, Jahrb. Geol. Bund.,
Bd. 103, p. 194, pl. 21, fig. 2.
1962. Not Globotruncana (Globotruncana) lapparenti coronata Bolli,
Pessagno, Micropaleont., vol. 8, No. 3, p. 362, pl. 3, figs. 10-12.
1962. Globotruncana linneiana coronata Bolli, Barr (part) , Paleonto-
logy, vol. 4, pt. 4, pp. 572, 573, pl. 70, ? figs. la-c; pl. 72, fig. 4;
not fig. 3.
Remarks.—Because of the confusion between M. cor-
onata (Bolli) and M. angusticarenata (Gandolfi), the
specimen figured as G. lapparenti coronata Bolli by Bolli
(1945) in plate 9, figure 15 is designated the lectotype of
Globotruncana lapparenti coronata. Furthermore, the speci-
mens figured by Bolli in text-figure 1: figures 21, 22 are
designated paralectotypes of G. lapparenti coronata. As
noted in the synonomy of M. angusticarenata (Gandolfi) ,
the syntypic specimen figured by Bolli in plate 9, figure I4
is regarded as M. angusticarenata.
M. coronata (Bolli) differs from M. angusticarenata
(Gandolfi) : (1) by being relatively planiform both spirally
and umbilically and (2) by having a wider double keel.
(The double keel of M. angusticarenata is narrow.)
306 PALAEONTOGRAPHICA AMERICANA (V, 37)
The free specimens figured by Mornod (1950, text-
figs. 13a-c) and by Subbotina (1953, pl. 8, figs. la-c) as G.
coronata are equated with the lectotype and paralectotypes
selected above. It should be noted that both Mornod and
Subbotina clearly showed extraumbilical-umbilical primary
apertures in their drawings.
Range.—M. helvetica assemblage zone, |W. archaeocre-
tacea subzone to G. bulloides assemblage zone, M. concavata
subzone.
Occurrence.—M. coronata has been observed in the
Early Santonian portion of the San Felipe formation at
Peregrina Canyon near Ciudad Victoria and in the Late
Turonian, Coniacian, and Early Santonian portions of the
San Felipe formation at Boca Canyon near Monterrey. In
Texas M. coronata has been observed in the Late Turonian
portion of the Eagle Ford group and in the Coniacian and
Early Santonian parts of the Austin chalk.
M. coronata is definitely known from the Late Tur-
onian and Coniacian of Bavaria, Switzerland, Austria, and
Russia. The writer has also examined it in Coniacian sam-
ples from the Funks formation of Yolo County, California.
Marginotruncana helvetica (Bolli)
Plate 53, figs. 9-13; Plate 54, figs. 1-3; Plate 99, fig. 4; Plate 100,
fig. 4
1945. Globotruncana helvetica Bolli, Eclogae Geol. Helv.. vol. 37, No.
2, pp. 226, 227, text-fig. 1: 9-12; pl. 9, figs. 6-8.
1952. Globotruncana helvetica Bolli, Sigal, 19th Congr. Géol. Internat.,
Monogr. Rég., Alger, ser. 1, No. 26, p. 31, text-fig. 32.
1954. Globotruncana helvetica Bolli, Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. 1, pp. 30, 31, pl. 3, figs. la-c; pl. 5, figs. 5, 6.
1955. Globotruncana helvetica Bolli, Schijfsma, Micropaleont., vol. 1,
No. 4, pp. 321-334, text-fig. 2 (part).
1957. Helvetoglobotruncana helvetica (Bolli), Reiss, Contr. Cushman
Found. Foram. Res., vol. 8, pt. 4, pp. 137, 138, text-fig. 5, fig. 1;
text-fig. 7, fig. m.
1957. Globotruncana helvetica Bolli, Bolli, U.S. Nat. Mus., Bull., No.
215, p. 56, pl. 13, figs. la-c.
1959. Ticinella helvetica (Bolli) , Banner and Blow, Paleontology, vol.
2, pt. 1, p. 24, pl. 3, figs. 2a, b.
1960. Globotruncana helvetica Bolli, Trujillo, Jour. Paleont., vol. 34,
No. 2, pp. 341, 342, pl. 50, figs. 2a-c.
Remarks.—Marginotruncana helvetica (Bolli) shows
the extraumbilical-umbilical aperture characteristic of
other species of Marginotruncana. Reiss (1957, text-fig.
7, fig. m) indicated that large portici exist on well-
preserved specimens of M. helvetica. An imperforate sin-
gle keel follows the dorsal periphery of larger ephebic
specimens of this species. Such keels are found on a number
of the writer’s Mexican specimens of M. helvetica. Smaller
neanic specimens such as the sectioned forms figured herein
from Texas lack keels. Because the writer feels that the
generic assignment of a species should be based on the tests
of full grown, ephebic individuals, this species, in spite of
its lack of true keels in the neanic stage of development, is
placed with Marginotruncana rather than with Whiteinella,
Pessagno, n. gen.
Marginotruncana helvetica (Bolli) differs from other
species of Marginotruncana by the hemispherical shape of
its chambers. It seems to have evolved via spiral flattening
from Whiteinella archaeocretacea Pessagno, n. sp. The form
figured by Trujillo (1960, pp. 340, 541, pl. 49, figs. 6a-c) as
“Rugoglobigerina prachelvetica Vrujillo” may represent
a transitional form linking M. helvetica (Bolli) with JW.
archaeocretacea Pessagno, n. sp. Whiteinella prachelvetica
(Trujillo) seems to be derived from a Whiteinella archaeo-
cretacea ancestor.
Range.—M. helvetica assemblage zone: M. sigali sub-
zone to W. archeocretacea subzone.
Occurrence.—M, helvetica (Bolli) is abundant in the
Early Turonian portion of the San Felipe formation crop-
ping out in Boca Canyon south of Monterrey, Mexico. In
Texas it has been observed by the writer in the Turonian
part of the Eagle Ford group at Chispa Summit (Chispa
Summit formation) and at Bouldin Creek, Travis County
(South Bosque formation) .
Elsewhere in the Western Hemisphere M. helvetica
was figured by Trujillo (1960) from the Turonian of
Shasta County, California, and by Bolli from the Turonian
of Trinidad, W. I.
M. helvetica is the Turonian of
France, Bavaria, Switzerland, Israel, Algeria, and Tunisia.
Schijfsma (1955, pp. 320-334) maintained that M.
helvetica occurs in the Lower Conician strata of ‘Tunisia.
The investigator has never noted M. helvetica in the Conia-
cian strata of North America. The lower portion of the
Austin chalk, for example, in its type area at Austin, Texas,
does not contain this species. Young (1960, p. 16) and
other students of the ammonite fauna of the Austin chalk
in its type area all agree that the lower part of the Austin
chalk is of Coniacian age. Much of the megafossil evidence
cited by Schijfsma for the Coniacian occurrence of M. hel-
vetica seems either contradictory or misleading.
°
also known from
Marginotruncana imbricata (Mornod)
Plate 57, figures 3-5
1950. Globotruncana imbricata Mornod, Eclogae Geol. Helv., vol. 42,
No. 2, pp. 589, 590, text-fig. 5: 2a-c, 3a-d; pl. 15, figs. 21-34.
1954. Globotruncana imbricata Mornod, Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. 1, pp. 34, 35, pl. 2, fig. 6; pl. 5, figs. 9, 210.
|
|
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 307
Remarks.—M. imbricata (Mornod) is somewhat similar
to M. marginata (Reuss). It differs from the latter species
by having a somewhat more spirally convex, thicker, and
more inflated test.
Range.—M. helvetica assemblage zone; M.
zone insofar as known from the present study.
sigali_ sub-
Occurrence.—During the course of this study M. im-
bricata has only been observed in the Turonian portion of
the San Felipe formation as exposed in Boca Canyon, south
of Monterrey, Mexico (Text-figure 1) .
Marginotruncana indica (Jacob and Sastry)
Plate 55, figures 3, 8-10; Plate 57, figures 6-9; Plate 98, figure 2
1950. Globotruncana indica Jacob and Sastry, Science and Culture,
vol. 16, No. 6, p. 267, text-figs. 2a-c.
1955. Globotruncana indica Jacob and Sastry, Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 19, text-fig. -: Sa, b.
1960. Praeglobotruncana concavata (Brotzen), Klaus, Eclogae Geol.
Helv. vol. 52, No. 2, p. 797, pl. 7, figs. 2a-c.
Description.—TVest trochospiral; planoconyvex. Spiral
side slightly convex to planiform; umbilical side convex.
Chambers nearly hemispherical in shape; four or five cham-
bers in the last whorl becoming progressively more convex
umbilically. Sutures on spiral side curved, raised, some-
times beaded; sutures on the umbilical side radial, straight,
and depressed. Umbilicus shallow and of moderate size;
thick, moderately large portici with infralaminal accessory
apertures extending into umbilicus. Early chambers of last
whorl often quite rugose umbilically. Narrow double keel
following spiral margin of test. Primary aperture extraumbi-
lical-umbilical in position; highly arched. Outer wall radial
hyaline perforate except for keel which is radial hyaline
imperforate. Septal wall microgranular hyaline, perforate;
portici microgranular hyaline, (?) perforate.
Remarks.—Jacob and Sastry noted in their original des-
cription of this species that it has a planoconvex test with
a flat spiral side and a moderately convex umbilical side.
They also noted and illustrated the presence of what is cur-
rently called an extraumbilical-umbilical aperture. Al-
though Jacob and Sastry indicated that the type locality of
this species is Cenomanian in age, it is likely that such an
age assignment is in error and needs restudy by Indian
paleontologists.
M. indica (Jacob and Sastry) is similar to M. renzi
(Gandolfi) (cf. emended definition of M. renzi herein) . It
differs from M. renzi largely in the radial, depressed,
straight to slightly curved nature of its sutures umbilically.
Range.—M. helvetica assemblage zone, W. archacocre-
tacea subzone to M. renzi assemblage zone. G. bulloides as-
semblage zone (?) ; M. concavata subzone (?).
M. indica has been observed in the G. bulloides sub-
zone, M. concavata subzone only where Austin strata assign-
able to the M. concavata subzone rest with marked dis-
conformity on Eagle Ford strata assignable to the M. hel-
vetica assemblage zone. In continuous sections where the
intervening M. renzi assemblage zone is present, M. indica
has not been observed in strata assignable to the M. conca-
vata subzone.
Occurrence—In Mexico M. indica has been observed
in the Turonian portion of the Agua Nueva formation at
Peregrina Canyon northwest of Ciudad Victoria and in the
Turonian and Coniacian portions of the San Felipe forma-
tion at Boca Canyon south of Monterrey (Text-figure 1) 5
In Texas M. indica occurs throughout the Turonian
portion of the Eagle Ford group at Chispa Summit in Jeff
Davis County; at Lozier Canyon and Sycamore Creek in
Terrell and Val Verde Counties; and at Waco (Atco Ce-
ment Quarry) in McLennan County (Text-figure 2). It has
been observed in the Coniacian portion of the Austin chalk
in Kinney County and in the Early Santonian portion of
the Austin chalk in McLennan County.
Marginotruncana marginata (Reuss) ®
Plate 54, figures 7-12; 16-18; Plate 56, figures 10-12; Plate 99,
figures 5-7
1845. Rosalina fag See Bouse Stuttgart, Poe ayes . Schweizer-
hart, Abth. 1, p. 36, pl. 8, figs. 54a, b, 74a, b; pl. i figs. 68a, b
(lectotype).
1854. Rosalina marginata Reuss, Reuss, K. Akad. Wiss. Wien., Math.—
Natur. KI., Denkschr., Bd. 7, p. 69, pl. 26, figs. la-c.
1946. Globotruncana marginata (Reuss), Cushman (part), U.S. Geol.
Sur., Prof. Paper, No. 206, pl. 62, figs. la-c; not 2a-c.
®The Agua Nueva formation at Boca Canyon occurs below San
Felipe strata assignable to the Cenomanian Rotalipora s.s. assemblage
zone.
6While the present report was in press, the writer learned that a
neotype had been established for Rosalina marginata Reuss by Dana
Jivova (1956, Universitas Carolina Geologica, vol. 2, no. 3, pp- 239-255,
pl. 1, figs. la-c) from Emscherian (Coniacian) marls (Planermergel)
cropping out near the village of Luzice in northern Bohemia. Although
Jirova’s neotype differs morphologically at the species level from the
form figured herein as M. marginata (Reuss), the writer feels that it
should be accepted to propagate taxonomic stability. Topotypes sent
to the writer by Jirova show extraumbilical-umbilical apertures and
large portici with infralaminal accessory apertures. Hence, neither the
diagnosis of the Marginotruncanidae Pessagno, new family nor the
the diagnosis of Marginotruncana Hofker (emended) is affected herein.
A topotype of R. marginata Reuss sent to the writer by Jirova will be
figured by the writer in a future paper.
The form figured in this report as M. marginata (Reuss) and by
Reuss (1854, pl. 26, figs. la-c) as Rosalina marginata (Reuss) should be
referred to Marginotruncana difformis (Gandolfi) (= Globotruncana
intermedia difformis Gandolfi). Forms correlative with M. marginata
s.s. Reuss are rare in the writer’s North American material and have
only been noted in the Coniacian portion of the Austin Chalk (‘“Atco”
member) south of Del Rio, Texas.
308 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 21
TEXT-FIGURE 22
zZinotruncana
(Reuss) 7
c
0.22410
0.084]0.084
inotruncana
PE 972
TX 353
PE 970
TX 353
| PE 975
TX 353
(Jacob and
Mar
i
Oo
fom
oO
~~
oO
re
iS)
i
fon
nN
oO
tN
(o)
[2-04 i
2.20
ack
OF
ie)
ere za ce
ae
Dee
fom por fo of
er
epee sf
aie a
All measurements in millimeters.
oO
je)
\o
pear
NS
(=)
oO
\o
ee)
Ht. double
Ht. double
at D'
keel
0
4
Double |
+
a
hN
* + = double keel present. - = double keel absent.
* Imperforate peripheral band present in early stage
not double keel.
» but
oO
Wo
(o)
Ne)
oO
i)
[o)
(o>)
(jo)
N
(o>)
(o>)
1950. Globotruncana (Globotruncana) sp. aff. renzi Thalmann-Gan-
dolfi, Reichel, Eclogae Geol. Helv., vol. 42, No. 2, pp- 612, 613,
pl. 16, fig. 8; pl. 17, fig. 8.
1953. Rotundina marginata (Reuss), Subbotina (part), Trudy, Vses.
Neft. Naukno—Issled. Geol.—Razved, Instit, n. ser., No. 76, p- 168,
pl. 5, figs. la-c; ?2a-c; 3a-c; not 4a-c, 5a-c.
1954. Globotruncana marginata (Reuss), Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. 1, pp. 46, 47, pl. 2, figs. 4a-c; pl. 7, figs. 5, 6.
1955. Globotruncana intermedia difformis Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 49, pl. 3, figs. 4a-5e.
1956. Marginotruncana marginata (Reuss) , Hofker, Neues Jahrb. Geol.
Palaeont., Abh. 103, pp. 322-324, text-figs. 2, ? 6, 7, not 8.
1957. Globotruncana schneegansi Sigal, Bolli, U.S. Nat. Mus., Bull.
No. 215, p. 58, pl. 14, figs. la-e.
1957. Not Globotruncana marginata (Reuss) , Edgell, Micropaleont.,
vol. 3, No. 2, p. 114, pl. 2, figs. 4-6.
1960. Praeglobotruncana renzi (Thalmann), Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 795, pl. 6, figs. ta-c. All measurements in millimeters.
=
~<
=
<
—
N
wm
RR
lo
-
io)
fo)
co
im
Waaunie
keel at D'
(o)
ro)
~
ra
oe bo
co
(>) (=
a 5 er
n un
(e)
a
Description.—Test trochospiral, biconvex to somewhat
spiroconvex with four to seven chambers in the final whorl;
GULF CrETACEOUS FORAMINIFERA: FESSAGNO 309
narrow double keel following periphery of last whorl; some-
times absent on last several chambers; usually but not al-
ways present in preceding whorl. Chambers spirally sepa-
rated by raised, curved sutures which often are slightly
beaded. Chambers umbilically separated by radial, straight,
depressed sutures; sutures of last several chambers rarely
slightly curved and raised. Early chambers of last whorl
sometimes rugose umbilically. Umbilicus wide and shallow;
stubby, massive portici extending into umbilicus in well-
preserved specimens. Primary aperture highly arched, ex-
traumbilical-umbilical in position. Infralaminal accessory
apertures on flanks of portici of well-preserved specimens
near juncture with sutures. Outer wall radial hyaline per-
forate except double keel which is radial hyaline imperfor-
ate; portict. microgranular hyaline perforate (?); septal
walls microgranular perforate. Pore frames markedly hexa-
gonal in shape (cf. Pl. 99, fg. 6).
Remarks.—In 1957 Bolli, et al. (p. 46) selected the
specimen represented by Reuss’s figures 68a-b (1845, p. 36,
pl. 13) as the lectotype of Rosalina marginata Reuss. Al-
though all of Reuss’s figures are small and generalized, the
lectotype figures show a form which has seven chambers in
the last whorl; curved sutures spirally; straight, radial su-
tures umbilically; and a broad umbilicus. Reuss failed to
show a peripheral view of any of the specimens illustrated
in his syntypic series. However, it can be inferred from
Reuss’s description (as noted by Bolli, et al., ibid.) that R.
marginata possesses the perpendicularly truncate margin
characteristic of all double keeled Cretaceous planktonic
Foraminifera. The lectotype selected by Bolli, et al., is from
the Planermergel (Turonian) of Bohemia. According to
Ellis and Messina (Catalogue of Foraminifera) Reuss’s
types are deposited in “Furstlich Lobkowitiz’sches Minera-
lien Kabinet—”, Bilina, Czechoslovakia.
In 1854 Reuss (pl. 26, figs. la-c) figured R. marginata
from the Gosau beds (Edelbachgraben) of Austria. This
specimen (cf. Reuss, 7bid., pp. 7-8) is assumedly from the
Lower Gosau beds (Gosaumergeln) . Reuss noted in his fau-
nal list that it occurs along with Rosalina canaliculata
Reuss. In the exam‘nation of topotypic material of R. can-
aliculata from this same Gosau locality the writer did find
one or two specimens of M. marginata (Reuss) (see M. can-
aliculata herein) .
Reuss’s (1854) figures la-c of R. marginata are im-
portant because they are large, clear, and certainly illustrate
his concept of this species. The figured specimen shows six
chambers in the final whorl separated by curved, slightly
raised sutures spirally and by radial, straight, depressed
sutures umbilically. The umbilicus or umbilical area is large
and a narrow double keel is present in the last whorl (cf.
fig. Ic).
The specimen figured by Reichel (1950, pp. 612, 613,
pl. 16, fig. 8; pl. 17, fig. 8) as Globotruncana (Globotrun-
cana) sp. aff. renzi Thalmann-Gandolfi as indicated in syno-
nymy, is assignable to M. marginata (Reuss). Reichel’s um-
bilical view of this specimen is interesting in that it clearly
shows portici with infralaminal accessory apertures.
M. marginata (Reuss) has been equated by a number
of workers with Globotruncana bulloides (Vogler) . For ex-
ample, the specimen figured from the Austin chalk by
Cushman (1946, pl. 62, figs. 2a-c, not la-c) as Globotrun-
cana marginata (Reuss) is actually assignable to Globo-
truncana bulloides Vogler. Likewise, the specimen figured
by Edgell (1957, p. 114, pl. 2, figs. 2-4) as Globotruncana
(Globotruncana) marginata (Reuss) is assignable to Globo-
truncana bulloides Vogler or perhaps is transitional to
A. cretacea (d’Orbigny). Edgell (cbid.) believed that Gilt.
bulloides Vogler is a junior synonym of R. marginata
Reuss.
The writer has sectioned a number of free specimens
of both M. marginata (Reuss) and Globotruncana bullo-
ics Vogler. The sections have been compared to Vogler’s
sectioned types of G. bulloides (lectotype selected herein) .
Marginotruncana marginata (Reuss) differs from Globo-
truncana bulloides Vogler (1) by having a narrower and
less massive double keel which is radial hyaline imperforate
as opposed to that of G. bulloides which is both radial
hyaline and ultregranular hyaline imperforate; (2) by lack-
ing highly inflated or vaulted chambers; (3) by having a
thinner test measured along T-T’ in thin-section; (4) by
lacking true tegilla with both infralaminal and intrala-
minal accessory apertures; (5) by having a primary aper-
ture which is extraumbilical-umbilical in position; (6) by
having depressed, straight, radial sutures umbilically; and
(7) by possessing a shallower umbilicus. Form analysis
measurements of M. marginata are presented in Text-figure
21.
The writer has examined the types of Globotruncana
wilsont Bolli at the U.S. National Museum, Washington,
D.C. The holotype appears to be closely related to M. mar-
ginata but shows depressed sutures both spirally and um-
bilically. The paratypes from the Maestrichtian portion of
the Guayaguayare formation show rugosites aligned in a
meridorial pattern and are clearly referrable to Rugotrun-
cana subcircumnodifer (Gandolfi) .
The writer also examined the holotype of Globotrun-
cana intermedia difformis Gandolfi (No. 20842) in the col-
lections of the Paleontological Research Institution, Ithaca,
310 PALAEONTOGRAPHICA AMERICANA (V, 37)
New York, and found it assignable to M. marginata
(Reuss) .
M. marginata seems to have evolved from Whiteinella
archacocretacea Pessagno, n. sp. through the acquisition of
a narrow double keel.
Range.—M. helvetica assemblage zone, M. sigali sub-
zone to G. bulloides assemblage zone, M. concavata sub-
zone (lower part) .
Occurrence.—In Mexico M. marginata occurs in the
Agua Nueva formation (Turonian) exposed at Peregrina
Canyon northwest of Ciudad Victoria and in the Turonian,
Coniacian, and Lower Santonian portions of the San Felipe
formation cropping out at Boca Canyon south of Monter-
rey. It also occurs in the Lower Santonian portion of the
San Felipe formation exposed at Mamulique Pass north of
Monterrey (Text-figures 1-2). In Texas M. marginata oc-
curs in the Turonian portion of the Eagle Ford group at
Chispa Summit, Jeff Davis County; at Bouldin Creek in
Travis County; at the Atco Cement Quarry (Waco, subsur-
face and surface) , McLennan County; and in the type area
of the Eagle Ford group (subsurface) in Dallas County
(Text-figures 1-2) .
M. marginata is also known from the Upper Cretaceous
of Russia, Bavaria, Switzerland, Austria, and Columbia.
Marginotruncana pseudolinneiana Pessagno, n. sp.
Plate 65, figures 24-27; Plate 76, figures 1-3
1960. Globotruncana lapparenti tricarinata (Quereau), ‘Tollmann,
Jahrb. Geol. Bund., Bd. 103, pp. 193, 194, pl. 21, figs. la-c.
Description.—Test lobulate, trochospiral; extremely
planiform, often concave spirally; planiform umbilically;
peripherally truncated by a wide double keel; rims of
double keel either not strongly beaded or beadless. ‘Test
comprised of two and one-half to three whorls of chambers
which gradually expand in size; seven to eight chambers in
final whorl. Chambers crescent-shaped spirally, separated by
raised, curved, slightly beaded or beadless sutures; chambers
subrectangular umbilically, separated by slightly curved,
raised, beadless or slightly beaded sutures. Umbilicus broad,
bordered by mildly elevated umbilical shoulder. Primary
aperture interiomarginal, extraumbilical-umbilical in posi-
tion, a lowly arched opening. Outer wall except for double
keel radial hyaline, perforate; double keel radial hyaline,
imperforate. Septal walls microgranular hyaline, sparsely
perforate.
Remarks.—Marginotruncana pseudolinneiana Pessagno,
n. sp. is nearly homeomorphic externally for Globotruncana
linneiana (d’Orbigny). It can be differentiated from G.
linneiana by the following criteria: (1) its primary aper-
ture is clearly extraumbilical-umbilical in position; (2) the
spiral surface of its test is more planiform and is often con-
cave; (3) its chambers are almost entirely crescent-shaped
spirally whereas those of G. linneiana are more typically
petaliform; and (4) it lacks the coarsely beaded sutures and
keels of G. linneiana. In thin-section, M. psewdolinneiana
Pessagno, n. sp. shows typical marginotruncanid double
keels which are entirely radial hyaline imperforate in char-
acter. G. linneiana and other double keeled species of Glo-
botruncana show keels which are both radial hyaline imper-
forate and ultragranular hyaline imperforate in character
(Text-figure 40). In addition, M. pseudolinneiana, n. sp.
shows earlier whorls which are more compressed along a
spival-umbilical axis and which seem to represent a M.
canaliculata stage of development.
M. pseudolinneiana, n. sp. seems to have arisen from
M. canaliculata (Reuss) by obtaining wider double keels
and by obtaining slightly curved, raised sutures umbili-
cally. Transitional forms occur in Lower Gosau samples.
It should be noted that the sectioned specimen from
the Austin chalk (Pe 859; Text-figure 51) listed under G.
linneiana was found to be referrable to M. pseudolinneiana
in the late part of this work.
Type locality —Marl from the Lower Gosau beds; Gos-
autal, Edelbachgraben, Austria. Type locality of Rosalina
canaliculata (Reuss) (Locality G-19 of W. W. Hay, Appen-
dix, Text-figure 63).
Deposition of types—The holotype and figured para-
types of this species will be deposited in the collections of
the U.S. National Museum, Washington, D.C.
Range.—M. helvetica assemblage zone to G. bulloides
assemblage zone, M. concavata subzone. (Composite Euro-
pean and North American range zone) .
Occurrence.—In Mexico M. pseudolinneina has been
observed in the Coniacian and Early Santonian portions of
the San Felipe formation. In Texas, M. pseudolinneiana,
n. sp. has been observed in the Coniacian and Early San-
tonian portions of the Austin chalk. Late Turonian of
California.
Marginotruncana renzi (Gandolfi)
Plate 55, figures 4-7; Plate 65, figures 20-23; Plate 98, figures 3, 4
1936. Globotruncana appenninica-linnei Renz (part), Eclogae Geol.
Helv., vol. 29, No. 1, pl. 6, figs. 16, 21-26; not 17-20; pl. 8, figs. 3
and 5; not fig. 2.
1942. Globotruncana renzi Thalmann, Amer. Assoc. Petrol. Geol., 27th
Ann. Conf., Denver, Colorado, U.S.A., program, p. 8, nomen
nudum.
1942. Globotruncana renzi Gandolfi, Riv. Ital. Pal., Ann. 48, mem. 4,
GULP CRETACEOUS FORAMINIFERA: PESSAGNO 51]
p. 124, text-figure 45a-c; pl. 4, fig. 15; not pl. 3, figs. la-c; not
pl. 4, figs. 16, 28, 29; not pl. 10, fig. 2.
1945. Not Globotruncana renzi Thalmann, Jour. Paleont., vol. 19, No.
4, p. 405 (type figure of Renz 1936, op cit., pl. 8, fig. 2) .
1954. Globotruncana renzi Thalmann and Gandolfi, Hagn and Zeil,
TEXT-FIGURE 23
Marginotruncana
PE 962
TX 30
PE 961
ID BIO)
PE 965
HW,< * 1(0)7/
Hagn & Zeil *
S
|
Cc
oO
ise)
[on
©)
=
io)
ee)
po
N
oO
b
nN
Nm
ie)
oO
Ne}
(ee)
1L5},0)=
ale
Ht. double
== ge 10)
All measurements in millimeters.
* G. schneegansi Sigal
(1954, pls D5 amles 2)
KK + double keeled early stage present.
- = double keeled early stage absent.
of Hagn and Zeil
Eclogae Geol. Helv., vol. 47, No. 1, pp. 37, 38, pl. 3, figs. 2a-c;
pl. 6, figs. 3-4.
1954. Globotruncana Aces Sigel Hagn and Zeil, Eclogae Geol.
Helv., vol. 47, No. S/epla bs figs 2:
1955. Globotruncana ps fhatmanen Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, pp. 60, 61, pl. 4, figs. 4a-c, 5a-c.
1957. ? Globotruncana renzi Gandolfi, Bolli, U.S. Nat. Mus., Bull.
No. 215, p. 58, pl. 14, figs. 3a-c.
1957. Globotruncana cf. lapparenti coronata Bolli, Bolli, U.S. Nat.
Mus., Bull., No. 215, p. 58, pl. 14, figs. 2a-c.
1957. Not Globotruncana coldreniensis Gandolfi, Contr. Cushman
Found. Foram. Res., vol. 8, pt. 2, p. 64, pl. 9, figs. 7a-c.
1960. Nou G lobotruncana renzi Thalmann, Klaus, Eclogae Geol. Helv.,
vol. 52, No. 2, p. 795, pl. 6, figs. 4a-c.
1960. Erie Ronee renz candor Trujillo (part), Jour. Paleont.,
vol. 34, No. 2, p. 343, pl. 5, figs. 4a-c; not figs. 3a-c.
Emended definition.—Test lobulate, trochospiral,
planoconvex with usually five or six chambers in the last
whorl. Spiral side planiform with curved, raised, often
beaded sutures; shape of chambers petaloid, often becom-
ing somewhat elongate. Umbilical side convex with raised,
curved sutures. Narrow double keel occurring peripherally
and following spiral margin of test; may merge to form
single keel. Primary aperture extraumbilical-umbilical with
portici present on well-preserved specimens. Outer wall
radial hyaline perforate except for keels which are radial
hyaline, imperforate. Septal walls microgranular hyaline
perforate; portici microgranular hyaline, perforate (?) .
Remarks.—Marginotruncana renzi (Gandolfi) has the
most chaotic taxonomic history of any species of planktonic
Foraminifera known to the writer. This chaotic history can
(1) The name Glo-
botruncana renzi was first used by Thalmann (1942; loc.
cit.). As noted by Ellis and Messina (Catalogue of Fora-
minifera) , Thalmann’s name is invalid as it was published
in the program of a scientific convention. Therefore,
Globotruncana renzi Thalmann is considered herein a
nomen nudum as it violates Article 9 (No. 4) of the In-
ternational Code of Zoological Nomenclature (IOI jer ©)
be summarized in the following steps:
(2) The name Globotruncana renzi was also intro-
duced by Gandolfi in 1942 somewhat subsequent to its in-
troduction by Thalmann. However, Gandolfi’s name was
published in a scientific journal with adequate figures and
plates. Gandolfi erected Globotruncana renzi Gandolfi syn-
typically figuring (1) a biconvex form and (2) a planocon-
vex form.
(3) In 1945 Thalmann redescribed Globotruncana
renzi Thalmann in the Journal of Paleontology and chose
plate 8, figure 2 of Renz (1936, see synonomy) as the holo-
type of his species. Gandolfi’s use of the specific name G.
renzi has clear priority over Thalmann’s (1945) use of the
same name.
312 PALAEONTOGRAPHICA AMERICANA (V, 37)
(4) In 1957 Gandolfi (see synonomy) believing that
Thalmann’s (1942) use of the name G. renzi had priority
over his own use of the name and believing that Thal-
mann’s form differed from his own, introduced the name
Globotruncana coldreriensis, selecting as holotype figs.
la-c (pl. 3) of Gandolfi (1942). The biconvex syntypes of
G. renzi Gandolfi pictured in pl. 3, figs. la-c (=holotype of
G. coldreriensis) ; in pl. 4, figs. 16; 28, 29 (not pl. 4, fig. 15;
pl. 10, fig. 2; not text-figs. 45a-c) thus can be correlated
with G. co!dreriensis.
In this monograph G. coldreriensis Gandolfi is consid-
ered to be a junior synonym of G. angusticarenata Gan-
dolfi. Furthermore, the planoconvex specimen figured by
Gandolfi (1942) in text-figures 45a-c is chosen as the lecto-
type of G. renzi Gandolfi and the specimen illustrated by
Gendolfi (1942) in plate 4, figure 15 is selected as the
paralectotype.
Ellis and Messina (Catalogue of Foraminifera; edi-
torial comments on G. coldreriensis) imply that the speci-
(1957) as the holotype of G.
coldreriensis automatically becomes a lectotype of G. renzi
Gandolfi at the same time. A lectotype, in the writer's
opinion, should be formally selected by a worker in accord-
ance with the Code of Zoological Nomenclature. In addi-
tion, it is difficult for the writer to understand how the
men selected by Gandolfi
same specimen can be selected simultaneously as a holotype
for one taxonomic species and the lectotype for another
taxonomic species.
M. renzi (Gandolfi) appears to be a near homeomorph
of M. indica (Jacob and Sastry). It can be differentiated
from M. indica, however, by its curved raised rather than
straight, depressed sutures umbilically, by having a well-
developed umbilical shoulder, and by its more lowly arched
primary aperture. It seems more likely at present that A.
renzt (Gandolfi) evolved from M. angusticarenata (Gan-
dolfi) through the flattening of the latter form’s dorsal
side and through the shift of the narrow double keel to
the spiral periphery.
The writer examined the holotype of Globotruncana
thalmanni thalmanni Gandolfi (No. 20851) at the Pale-
ontological Research Institution, Ithaca, New York. This
species is a planoconvex form that is regarded herein as a
variant of M. renzi (Gandolfi). It differs from the selected
lectotype and paralectotype only in the less petaloid and
more elongate, crescent-shaped character of its chambers
spirally. Moreover, a study of suites of specimens from the
Austin chalk indicates that the petaloid form seems to inter-
grade with the less petaloid form. Hence, G. thalmanni thal-
manni Gandolfi is regarded as a junior synonym of M.
renzi. (Gondolft) .
Specimens figured by Bolli (1957, loc. cit.) as Globo-
truncana renzt Gandolfi and Globotruncana cf. lapparenti
coronata Bolli were both examined by the writer in the col-
lections of the U.S. National Museum, Washington, D.C,
The form figured as G. renzi Gandolfi shows a great deal
of test contortion, but seems closely allied to M. renzi. The
specimen figured as G. cf. lapparenti coronata is similar to
the lectotype of G. renzi selected herein. It shows a plano-
convex test, petaloid chambers spirally, raised, curved
sutures umbilically, and a narrow double keel that follows
the spiral periphery of the last whorl.
Form analysis measurements for M. renzi are pre-
sented in Text-figure 25. A comparison of these measure-
ments with those of M. indica (Text-figure 22
that the separation of the two species must be largely based
indicates
on external morphological criteria. However, a comparison
of these measurements with those of M. angusticarenata
(Text-figure 18) indicates that M. renzi can be separated
from M. angusticarenata on the basis of its T’/X/TX values.
M. angusticarenata has a mean T’X/TX value of 0.575
whereas M. renzi has a mean ‘T’X/TX value of 1.32.
Range.—M. helvetica assemblage zone, W. archaeocre-
tacea subzone to G. bulloides assemblage zone, M. conca-
vata subzone.
Occurrence.—M. renzi occurs in the Agua Nueva forma-
tion (Upper ‘Turonian portion) at Peregrina
northwest of Ciudad Victoria. It also occurs in the Late
Turonian, Coniacian, and Lower Santonian portions of the
San Felipe formations at Boca Canyon south of Monterrey
Canyon
and is known in the Lower Santonian part of the San Felipe
formation in the Sierra Madre Oriental west of Tampico;
at Peregrina Canyon northwest of Ciudad Victoria; and at
Mamulique Pass north of Monterrey (Text-figures 1-2) .
In Texas M. renzi has been observed in the Upper
Turonian portion of the Eagle Ford group at Lozier Can-
yon and Sycamore Creek in Terrell and Val Verde Coun-
ties (Boquillas formation; Text-figure 2); at Bouldin
Creek in Travis County (South Bosque formation) ; and at
Atco in McLennan County (South Bosque formation;
Socony Mobil Research Lab.; Waco Core of Eagle Ford;
see Brown and Pierce, 1962). M. renzi likewise occurs in
the Coniacian and Lower Santonian portions of the Aus-
tin chalk at Lozier Canyon, Sycamore Creek, Pinto Creek,
and Cow Creek in Terrell, Val Verde, and Kinney Counties;
in the Coniacian portion of the Austin chalk at Bouldin
Creek in Travis County; and in the Lower Santonian por-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 313
tion of the Austin chalk at Waco in McLennan County and
at Dallas in Dallas County.
M. renzi is also known from approximately the same
horizons in Bavaria, Switzerland, Italy, Trinidad, and Cali-
fornia.
Marginotruncana sigali (Reichel)
Plate 54, figures 4-6; Plate 56, figures 1-3; Plate 57, figures 1, 2;
Plate 98, figu.es 6, 7
1950. Globotruncana (Globotruncana) sigali Reichel, Eclogae Geol.
Helv., vol. 42, No. 2, pp. 610-612, text-figs. 5, 6; pl. 16, fig. 7;
jal Wry tah
1952. Globotruncana schneegansi Sigal, 19th Cong. Géol. Internat.,
Monogr. Rég. Alger, ser. 1, No. 26, p. 33, text-fig. 34 (3 figs.).
1954. Globotruncana sigali Reichel, Hagn and Zeil, Eclogae Geol.
Helv. vol. 47, No. 2, pp. 35, 36, pl. 2, figs. la-c; pl. 6, fig. 2
1954. Not Globotruncana schneegansi leer Hagn and Zeil, Eclogac
Geol. Helv., vol. 47, No. 2, p. 37, pl. 5, fig. 12.
1957. Not Globotruncana schneegansi Sea Bolli, U.S. Nat. Mus.,
Bull., No. 215, p. 58, pl. 14, figs. la-c.
1960. Globotruncana schneegansi Sigal, Trujillo, Jour. Paleont., vol. 34
No. 2, pp. 343, 344, pl. 49, figs. 9a-c.
1960. ? Praeglobotruncana schneeganst (Sigal), Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 796, pl. 6, figs. 5a-c.
Remarks.—Marginotruncana sigali is unique among
species of Marginotruncana in that it possesses a well-
developed single keel. It is interesting that Reichel (1950)
in his illustration of the holotype (text-figure 5c, p. 610)
clearly showed the large portici with infralaminal accessory
apertures characteristic of Marginotruncana.
The writer believes that Globotruncana schneegansi
Sigal is a junior synonym of Globotruncana (G.) sigali
Reichel. Text-figure 24 shows form analysis measurements
of both North American and Algerian specimens of ].
sigali and M. schneegansi. Text-figure 25 is a scatter plot
of the I’X/TX values and D-D’ values of the same speci-
mens. The sectioned specimen (so-called “cotype’) of G.
(G.) sigali Reichel figured by Reichel (1950) in text-fig-
ure 6 has a T’X/TX value of 0.46. Approximate measure-
ments of T’X and TX from Sigal’s drawings of the holo-
type of G. schnecgansi and Reichel’s drawings of the holo-
type of G. sigali indicate that they both have T’X/TX
values of about 1.0. Thus, the holotypes of both species are
relatively similar in terms of their T’X/TX values. Further-
more, the holotypes of both these species share similarly
shaped chambers both spirally and umbilically as well as a
single keel and essentially the same geologic range. Through
the kindness of J. Sigal the writer obtained specimens of
G. sigali Reichel and G. schneegansi Sigal from the Upper
Turonian of Algeria (Constantine Region, sample 14806) .
The sectioned specimen figured by Hagn and Zeil
(1954, see synonymy) as Globotruncana schneegansi Sigal
TEXT-FIGURE 24
ali
(Reichel)
PE 1003
142
105
Marginotruncana
TX
‘si
Reichel 1950
PE 1004
PE 1005
PE 1007
PE 1008
TX 105
PE 1009
MX
10.715 J0.674 J0.659
xt :
Angle
All measurements in millimeters.
* So-called "cotype" of Reichel 1950.
** Specimen of M. sigali (Reichel) from Sigal. Turonian of Algeria.
* Specimen of M. schneegansi (Sigal) from Sigal. Turonian of Algeria.
5
TEXT-FIGURE 2: (1) = Globotruncono sigali Reichel, 1950, fig. 6,
so-called ‘‘cotype
lo’ Marginotroncona sigalt (Reichel) (2) = Hypotypes of Globotruncana schneegansi
Sigol from Sigal
(3) = Hypotype of Globotruncono sigali Reichel
from Sigal
at —— a 4
°o.3
0.700 }-
o-2 Ps
0.600
°
o.}
: 2
= °
2 0.500}- °
f=)
°
0.400 -
°
0.300 1 Jt 1 1 | ! it 1
01 0.5 10
T X/TX
possesses a narrow double keel, is nearly planoconvex, and
has well-developed umbilical shoulders. It thus seems to be
referrable to M. renzi (Gandolfi) (see emended definition
herein.) .
The writer has examined the specimen figured by Bolli
(1957, see synonomy) as Globotruncana schneegansi Sigal
in the collections of the U.S, National Museum, Washing-
9
514 PALAKONTOGRAPHICA AMERICANA (V, 37)
ton, D.C. This specimen shows a distinct narrow double
keel on the first two chambers of the last whorl which
merges to form a single keel. The lenticular shape of its
test, the possession of straight to slightly curved depressed
sutures umbilically, and its possession of a double keel place
this form in M. marginata (Reuss). Other specimens of
G. schneegansi given to the writer by Bolli in 1955 clearly
show single keels both in free specimens and in thin-section.
M. sigali seems to have evolved from Whiteinella arch-
aeocretacea Pessagno, n. sp. or Whiteinella inornata (Bolli)
during Early Turonian times through the acquisition of a
single keel.
Range.—M. helvetica assemblage zone: M. sigali sub-
zone to W. archaeocretacea subzone. The extension of the
range of this species under the name of G. schneegansi Sigal
by Bolli (loc. cit.) into the M. renzi assemblage zone must
be discounted as Bolli apparently included both double and
single keeled forms under the same name.
Occurrence.—M. sigali occurs throughout the Turonian
of Mexico. It has been observed in the Agua Nueva forma-
tion at Peregrina Canyon northwest of Ciudad Victoria and
in the San Felipe formation at Boca Canyon south of
Monterrey (Text-figures 1-2) .
In Texas, M. sigali occurs throughout the Turonian
portion of the Eagle Ford group at Chispa Summit, Jeff
Davis County; Lozier Canyon, ‘Terrell County; and Syca-
more Creek, Val Verde County; Bouldin Creek, Travis
County; at Atco near Waco, McLennan County; and at
the type locality of the Eagle Ford in Dallas, Dallas County.
Formational units present in these areas are indicated in
Text-figure 2.
M. sigali is known from the Turonian of Trinidad,
California, Bavaria, France, Switzerland, Algeria, and
Tunisia. Collignon (1959, p. 46, table 5) reported this
species (under the name of G. schneegansi) in the Lower
Coniacian of Madagascar in his Peronisceras dravidicum
assemblage zone. This occurrence should be reinvestigated
inasmuch as G. schneegansi has been confused by some
workers with M. renzi (Gandolfi) and M. marginata
(Reuss) .
Famliy GLOBOTRUNCANIDAE Brotzen, 1942
Type genus.—Globotruncana Cushman, 1927.
Remarks.—The diagnosis presented by Loeblich and
Tappan (1964, p. C662) in the Treatise of Invertebrate
Paleontology for the Globotruncanidae is as follows: “Test
trochospiral, chambers spherical to angular, commonly
truncate keeled; primary aperture umbilical, covered by
spiral system of tegilla, with accessory intralaminal and in-
fralaminal apertures”. This diagnosis is generally followed
herein. However, emendations should be noted: (1) The
tegilla of the Globotruncanidae are microgranular hyaline,
perforate (cf. Plate 95, fig. 13); (2) the septal walls are
microgranular hyaline perforate; (3) the outer wall of the
test is radial hyaline perforate; and (4) the keels are
canaliculate, predominantly radial hyaline imperforate,
but sometimes in part ultragranular hyaline, imperforate
(Gi IAL Gay sutey, 29).
It is interesting to note that the thick “calcite crust”
which was demonstrated by Bé and Ericson (1963, pp. 65-
81) to form an important component of the test of many
Recent species of Globorotalia s.s. is absent among the
Globotruncanidae and indeed among all Upper Cretaceous
Globigerinacea. Thus, the secretion of a thick ‘‘calcite
crust” among the Globigerinacea seems to be a relatively
recent phenomenon in their evolution probably dating
only as far back as the Early or Middle Tertiary.
The Globotruncanidae Brotzen differ from the Mar-
ginotruncanidae Pessagno, n. family: (1) by possessing
spirally arranged tegilla with both intralaminal and infrala-
minal accessory apertures rather than portici with infrala-
minal accessory apertures; (2) by having a primary aper-
ture which is umbilical rather than extraumbilical-umbili-
cal in position; and (3) by usually being more deeply
umbilicate.
The Globotruncanidae Brotzen differ from the Aba-
thomphalidae Pessagno, n. family (1) by having tegilla
with both infralaminal and intralaminal accessory apertures
rather than tegilla with only infralaminal accessory aper-
tures and (2) by having an umbilical rather than an extra-
umbilical-umbilical primary aperture.
The Globotruncanidae evolved from the Margino-
truncanidae via the shift of the primary aperture from an
extraumbilical-umbilical position to an umbilical position,
the enlargement of the portici to form tegilla, and the ac-
quisition of intralaminal accessory apertures in the tegilla.
The Globotruncanidae, on the other hand, probably gave
rise to the Abathomphalidae through the shift of the pri-
mary aperture from an umbilical position to an extraumbi-
lical-umbilical position and the loss of intralaminal acces-
sory apertures in the tegilla (see Abathomphalidae) . The
evolution of the Globotruntanidae from the Marginotrun-
canidae seems to reflect proterogenesis among the Globi-
gerinacea whereas the evolution of the Abathomphalidae
from the Globotruncanidae seems to reflect palingenesis
among the Globigerinacea.
The phylogeny of the Globotruncanidae at the generic
level is presented in ‘Text-figure 26. It is likely that Arch-
GuLr CRETACEOUS FORAMINIFERA: PESSAGNO
aeoglobigerina Pessagno, n. genus arose from a Whiteinella
Pessagno, n. genus ancestor through the shift of the primary
aperture from an extraumbilical-umbilical position to an
umbilical position, the enlargement of the portici to form
tegilla, and the acquisition of intralaminal accessory aper-
tures in the tegilla. Many of the early basic species of Globo-
truncana s.s. such as Globotruncana lapparenti Brotzen S.s.,
Globotruncana bulloides Vogler, Globotruncana fornicata
Plummer, and Globotruncana stuartiformis Dalbiez seem to
have arisen from an Archaeoglobigerina cretacea (d’Or-
bigny) or Archaeoglobigerina blowi Pessagno, n. sp. via the
acquisition of strongly truncated or angulated peripheries
and single or double keels (Text-figures 34-35) . The writer
does not feel at present that Globotruncana was derived
from Marginotruncana Hofker although this is a definite
possibility. The keel structure of most double-keeled species
of Marginotruncana seems different from that of most
double-keeled species of Globotruncana in that it is entirely
radial hyaline in character and shows no ultragranular
hyaline structure.
Archaeoglobigerina Pessagno, n. genus gave rise to
Rugoglobigerina Bronnimann through the acquisition of
rugosities or costellae aligned in a meridorial pattern.
Rugoglobigerina in turn gave rise to Rugotruncana through
the acquisition of a strong double-keeled, truncate peri-
phery, and the spiral-umbilical compression of its chambers.
The complex phylogeny of the Globotruncanidae at
the species level will be discussed under subsequent generic
and specific headings.
Range.—M. renzi assemblage zone to Gilt. contusa—
stuartiformis assemblage zone. Late Coniacian to Late
Maestrichtian.
Occurrence.—Upper Cretaceous, World-wide.
Genus ARCHAEOGLOBIGERINA Pessagno, new genus
Type species.—Archacoglobigerina blowi Pessagno, new
species.
Description.—Yest trochospiral, biconvex to slightly
spiroconvex, umbilicate; periphery rounded, but not trun-
cate; with or without imperforate peripheral band or
weakly developed double keel. Chambers spherical to
ovate, inflated. Sutures depressed on both spiral and um-
bilical sides, straight to curved. Wall perfectly smooth to
somewhat rugose; rugosities not aligned in meridorial pat-
tern. Primary aperture umbilical, interiomarginal, covered
by tegilla with intralaminal and infralaminal accessory
apertures in perfectly preserved specimens. Outer wall
radial hyaline perforate except for keels which are both
315
O19
= 5
s c
= 5
S| $ Text — Figure 26 Phylogenetic Relationship of Upper Cretaceous
Su rar
e383 £3 Globotruncanidae at the Generic Level
Pi & B
5 2s <io
al ca
5} w mise
é 3
> z
2 at
°
e
° r=
c c * oe “
5 S 2 a
8 c g ° z 4
= 5 ¢ i 3
<= ° > e ° o
2 S 5 E q E
= E 3 E 3 2
% 3 s = Ey 3
o ~4, a a ie =
= 3
2
2
oO
Camponicn
Taylorian
Archaeoglobigerina) in. gen
Upper Cretaceous (part.)
Santonian
Austinian
=
o
5
~
=
)
rv)
r
5
o
c
a
S
=
Turonion
Eaglefordian
at at
% Not seen during this study
+ = extinction. Swellings in life line indicate times of greater abundance and speciation
radial hyaline imperforate and partly ultragranular hyaline,
imperforate and the rugosities which are ultragranular hya-
line, imperforate. Septal walls and tegilla microgranular
hyaline, finely perforate.
Remarks.—Archaeoglobigerina Pessagno, n. genus dif-
fers from Rugoglobigerina Bronnimann by lacking rugosites
or costellae arranged in a distinctive meridorial pattern
(see remarks on Rugotruncana). Archaeogloberina differs
from Globotruncana s.s. (Cushman) (1) by lacking a trun-
cate or angled periphery; (2) by having spherical to ovoidal
chambers; (3) by lacking strongly developed keels; and (4)
by having sutures which are predominantly depressed rather
than raised and often beaded.
Keels when present with both Archacoglobigerina and
Rugoglobigerina are weakly developed and do not give the
periphery a marked truncate or angled aspect. Most speci-
mens of the type species 4. blow: Pessagno, n. sp. lack keels
although they frequently show imperforate peripheral
bands.
316 PALAKONTOGRAPHICA AMERICANA (V, ¢
Range.—M. renzi assemblage zone (upper part) to
Globotruncana fornicata—stuartiformis assemblage zone,
Rugotruncana subcircumnodifer subzone insofar as known.
South America, West
Occurrence.—North America,
Indies, Eurasia, Australia.
Archaeoglobigerina blowi Pessagno, new species
Plate 59, figures 1-10; Plate 94, figures 2-3
Description.—Test — trochoid; lobulate peripherally.
Chambers spherical, nearly as elongate as wide; about four
or five in last whorl, rapidly increasing in size. Coiling pre-
dominantly dextral; sutures depressed, radial, straight to
slightly curved spirally and umbilically. Umbilicus medium-
sized and deep covered by tegilla with intralaminal and
infralaminal accessory apertures in well-preserved speci-
mens. Periphery occasionally with weakly developed double
keel which occurs chiefly on the first one or two chambers
of the final whorl, but usually keel-less with or without an
imperforate peripheral band; nontruncate. Test surface
either smooth throughout or somewhat rugose on the
earlier chambers; last two or three chambers usually smooth
irregardless of previous ornamentation. Primary aperture
interiomarginal, umbilical in position. Outer wall except
for rugosities, keels, and imperforate peripheral band,
radial hyaline, perforate; rugosities ultragranular hyaline,
imperforate; keels radial hyaline and ultragranular hyaline,
imperforate; peripheral band radial hyaline imperforate.
Remarks.—A. blowi Pessagno, n. sp. is closely related
to A. cretacea (d’Orbigny) . It differs from the latter species
(1) by possessing more spherical and inflated chambers
which are nearly as wide as long and by showing a more
(2) by
markedly lobulate periphery. Transitional forms between
rapid increase in chamber size, and having a
these two species are common at some horizons. 4. blowi
Pessagno, n. sp. differs from A. bosquensis Pessagno, n. sp.
(1) by being lower spired; (2) by having four or five rather
than six or seven chambers in the last whorl; (3) by having
a larger umbilicus; (4) by displaying chiefly dextral coiling;
and (5) by showing a more rapid increase in chamber size.
Archaeoglobigerina blowi Pessagno, n. sp. gave rise to
f is f
Rugoglobigerina rugosa (Plummer)
Rugoglobigerina tradinghousensis Pessagno, n. sp. in Early
Campanian or Taylorian times through the development of
meridorially arranged rugosities.
and most likely to
This species is named after W. H. Blow in honor of
his contributions to the geology of the West Indies and to
micropaleontology.
Type locality—TX 252. Lowei
Taylor marl. Buff-
)
)
7)
colored to gray-colored calcareous mudstone breaking with
concoidal fracture exposed on Tradinghouse Creek, Mc-
Lennan County, Texas; 1.5 miles due west of juncture be-
tween Tehuacana Creek and Tradinghouse Creek; 1 mile
S65E of Harrisson Switch (large meander) in Tradinghouse
Creek; 0.2 miles due south of county road bridge over
Tradinghouse Creek (Waco East Quadrangle) ; 53.5 feet
above creek level in an exposure of about 77.5 feet of sec-
tion.
Deposition of types—The holotype and figured para-
types of A. blow? Pessagno, n. sp. will be deposited in the
collections of the U.S. National Museum, Washington, D.C.
Unfigured paratypes will be deposited in the Paleontologi-
cal Research Institution, Ithaca, New York.
Range.—M. renzi assemblage zone to G. fornicata—
stuartiformis assemblage zone, R. suwbcircumnodifer subzone
insofar as known.
Occurrence.—A, blowi appears to be rare in Mexico
although its sparsity in Mexican samples may be biased by
the erection of this species after the detailed analysis of the
Mexican samples. It has been noted in the Early Campanian
portion of the San Felipe formation and in the Early and
Late Campanian portions of the Méndez shale.
In Texas 4. blow?, n. sp. occurs in the Coniacian and
Santonian portions of the Austin chalk, throughout the
Taylor formation (“Lower Taylor marl member’, Wolfe
City sand member, Pecan Gap chalk member, and “Upper
Taylor marl member’), in the Upson Clay, and in the
Neylendville marl (Text-figure 2) .
In Arkansas it occurs in the Brownstown marl, the
Ozan formation, the Annona chalk, the Marlbrook marl,
and the Saratoga chalk.
There is some indication that A. blow7, n. sp. is more
abundant in the Boreal faunal province than it is in the
Tethys faunal province.
Archaeoglobigerina bosquensis Pessagno, new species
Plate 60, figures 7-12
Description.—Test coiled in retatively high trochospiral
coil; six to seven chambers in last whorl. Coiling sinistral
or dextral with no preferance insofar as known. Chambers
spherical in shape about as wide as long; tending to shift
toward the umbilicus with ‘coiling. Sutures curved, radial,
depressed both spirally end umbilically. Umbilicus deep
and of moderate to small size. Early chambers of last whorl
somewhat rugose. Keels, imperforate peripheral bands lack-
ing in specimens thus far encountered. Primary aperture
interiomarginal, umbilical in position; no evidence of
tegilla due to unfavorable conditions of preservation in
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 317
Austin chalk. Outer wall radial hyaline perforate; septal
walls microgranular hyaline, finely perforate.
Remarks.—A. bosquensis Pessagno, n. sp. differs from
A. blowi Pessagno, n. sp. (1) by being equally dextrally and
sinistrally coiled; (2) by having a relatively high trochoidal
spire; (3) by having a somewhat smaller, deeper umbilicus;
(4) by usually having six or seven as opposed to four or
five chambers in the last whorl; (5) by having chambers
which gradually increase in size; and (6) by lacking keels
and imperforate peripheral bands. A. bosquensis derives its
name from that of the South Bosque River.
Type locality —TX 226. Austin chalk (“Atco” mem-
ber), Lover's Leap, Cameron Park, Waco, McLennan
County, Texas. White marlstone 107 feet above the level of
the South Bosque River.
Deposition of types.—The holotype and figured para-
type of A. bosquenis Pessagno, n. sp. will be deposited in the
collections of the U.S. National Museum, Washington, D.C.
Range.—M. renzi assemblage zone to G. bulloides as-
semblage zone, M. concavata subzone insofar as known.
Occurrence.—In Mexico A. bosquensis has been ob-
served in San Felipe strata assignable to the M. concavata
subzone at MX 102 (see Appendix) along the road from
Antiguo Morelos to Ciudad del Maijz in the Sierra Madre
Oriental. In Texas A. bosquensis occurs in the Coniacian
portion of the Austin chalk (“Atco” member, part) in Val
Verde, Kinney, and Travis Counties and in the Lower San-
tonian portion of the Austin chalk (“Atco”’, “Bruceville’,
and “Hutchins” members) in Kinney, McLennan, and
Dallas Counties.
Archaeoglobigerina cretacea (d’Orbigny)
Plate 70, figures 3-8; Plate 94, figures 4-5
1840. Globigerina cretacea d’Orbigny, Soc. Géol. France, Mém., Paris,
vol. 2, No. 1, p. 34, pl. 3, figs. 12-14.
1936. Globotruncana globigerinoides Brotzen, Sver. Geol. Unders.
Awvhi, Ser. ‘G; No: 390; Ars. 30; No: 3; p. 177, pl. 12, figs. 3a-c;
pl. 13, fig. 3.
1956, Globotruncana saratogaensis (Applin), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, p. 544, pl. 21, figs. 1-3.
1957. Globotruncana (Globotruncana) globigerinoides Brotzen, Edgell,
Micropaleont., vol. 3, No. 2, pp. 112, 113, pl. 2, figs. 13-15.
1960. Globotruncana cretacea (d’Orbigny), Banner and Blow, Contr.
Cushman Found. Foram. Res., vol. 11, pt. 1, pp. 8-10, pl. 7, figs.
la-c.
1964. Globotruncana mariai Gandolfi, Martin, Jahrb. Geol. Bund.,
Sond. 9, p. 82, pl. 9, figs. 7a-c.
Remarks.—For a number of years this species has been
used as a “waste basket” by students of Foraminifera to
include any Globigerina-like planktonic Foraminifera
ranging in age from Lower Cretaceous to Recent. The ex-
tensive synonomy given by Ellis and Messina (1940) in the
Catalogue of Foraminifera clearly indicates the misuse of
this specific name.
Although D’Orbigny (1840) did not designate a defin-
ite type locality for Globigerina cretacea he did cite its oc-
currence at the Saint Germain Basin near Paris, France, and
in England. As the first of these localities is at least more
definite it should be regarded as the type locality or area
of G. cretacea dOrbigny.
In 1960 Banner and Blow (pp. 8-10) made an extensive
study of D’Orbigny’s type material on deposit in the Na-
tional Museum of National History in Paris. They found
one vial containing six specimens from the Saint Germain
locality mentioned by D'Orbigny. The best preserved of
these six specimens was selected by Banner and Blow as the
lectotype of Globigerina cretacea d’Orbigny. Seven other
specimens in the D’Orbigny collection labelled Globigerina
cretacea VOrbigny were said by Banner and Blow to be
from an unknown locality but were in a superb state of
preservation with three of the seven specimens actually
showing tegilla. Banner and Blow inferred that these speci-
mens are definitely assignable to the Globotruncanidae and
are clearly conspecific with their lectotype of Globigerina
cretacea.
The specimen chosen by Banner and Blow as the lecto-
type of G. cretacea is perhaps an unfortunate choice for a
lectotype. The syntypic specimen figured by D’Orbigny
(1840, p. 34, pl. 3, figs. 12-14) for Globigerina cretacea is
distinctly different from that figured by Banner and Blow
as their lectotype. D’Orbigny’s specimen shows a markedly
lobulated periphery, and a more rapid increase in chamber
size in the last whorl. The lectotype of Banner and Blow
shows a mildly lobulate periphery, spherical chambers
which are I.3 to 1.4X wider than long, and a more gradual
increase in chamber size. Actually D'Orbigny’s figured
specimen is relatively close in appearance to A. blow? Pes-
sagno, n. sp. As noted previously, both of these forms are
closely related and it is likely that both forms occurred to-
gether in the samples D’Orbigny studied.
Specimens of A. cretacea (d’Orbigny) encountered dur-
ing this study closely resemble the lectotype selected by
Benner and Blow (1960). Their peripheries are nontrun-
cate and usually possess either an imperforate peripheral
band or a weakly developed double keel, but sometimes
may lack both of the former structures. The double keels
of specimens figured in Plate 70 (figures 3-8) are by no
means as strongly developed as indicated by the illustrator.
The sectioned specimen figured in Plate 94 (figure 4) shows
the actual strength of keel development.
A. cretacea (d’Orbigny) probably evolyed from an A.
318 PALAKONTOGRAPHICA AMERICANA (V, 37)
blow? Pessagno, n. sp. ancestor. Transitional forms are com-
mon and the A. blowi stage of development can be seen
spirally in the early whorls of some specimens of A. cretacca.
Range.—?M. renzi assemblage zone; G. bulloides assem-
blage zone, M. concavata subzone to G. fornicata-stuarti-
formis assemblage zone, R. swbcircumnodifer subzone.
Occurrence.—A. cretacea has not been observed in any
of the writer’s numerous Mexican Upper Cretaceous sam-
ples. In Texas it occurs in the Santonian portion of the
Austin chalk (G. bulloides assemblage zone) in Kinney,
Travis, McLennan, and Dallas Counties (Text-figure 2) . It
likewise has been observed in the “Lower Taylor marl” in
Travis, McLennan, and Dallas Counties; in the Wolfe City
sand in McLennan County; in the Pecen Gap chalk in Me-
Lennan County; in the “Upper Taylor marl” in Travis and
Limestone Counties; and in the Upson clay in Maverick
County (Text-figure 2). In southwestern Arkansas it has
been observed in the Brownstown marl, the Ozan forma-
tion, the Annona chalk, and the Marlbrook marl.
A. cretacea (dOrbigny) has been observed by the
writer in Lower Maestrichtian samples from New Jersey.
It occurs in the Campanian of France and Australia and in
the Senonian of Sweden. At present, the geographic occur-
rences of this species seem to indicate that it is chiefly
Boreal or Austral in terms of its distribution.
Genus GLOBOTRUNCANA Cushman, 1927
Type species —Pulvinulina arca Cushman, 1926.
Remarks.—The diagnosis (description only) of Loeb-
lich and Tappan (1964, pp. C662-663) is followed herein
for the most part. However, the writer regards Marginotrun-
cana Holker (1956) (emended herein), Globotruncanella
Reiss (1957) (emended herein), and Rugotruncana Bron-
nimann and Brown (1955) (emended herein) as morpho-
logically and phylogenetically distinct genera. Marginotrun-
cana Hotker is the type genus of the Marginotruncanidae
Pessagno, n. fam. and Globotruncanella Reiss is placed in
the Abathomphalidac Pessagno, n. fam. Rugotruncana
Bronnimann and Brown is retained in the Globotrun-
canidae.
Globotruncana differs from Archacoglobigerina Pes-
sagno, n. genus by having a periphery which is markedly
angled or truncated by either a well-developed single or
double keel. It differs from Rugoglobigerina Bronnimann
for the above reasons and also because it lacks rugosities
arranged in a distinctive meridorial pattern. Likewise, Glo-
botruncana differs from Rugotruncana Bronnimann and
Brown by lacking rugosities arranged in a distinctive meri-
dorial pattern (see Rugotruncana, herein) .
The test of Globotruncana s.s. possesses an outer wall
which is predominantly radial hyaline perforate. However,
rugosities, coarse spines, and similar ornamental features
are ultragranular hyaline imperforate. The keels of Globo-
truncana are either entirely radial hyaline imperforate if
single or both radial hyaline imperforate and ultragranular
hyaline imperforate if double. Among double-keeled species
such as Globotruncana fornicata Plummer, Globotruncana
bulloides Vogler, and Globotruncana austinensis Gandolfi,
ultragranular hyaline material occurs chiefly on the outer
portions of the spiral and umbilical rimlike components of
the double keel and is plastered on to a radial hyaline base
(Text-figure 40). Usually the radial hyaline portion of the
double keel structure forms first. Ultragranular hyaline cal-
cite is then plastered on to the radial hyaline portion of the
rims strengthening the appearance of the double keel. Often
the final chamber of such a double-keeled species may show
either a wide radial hyaline imperforate peripheral band or
a weakly developed radial hyaline imperforate keel whereas
earlier chambers in the final whorl show a strong keel with
a radial hyaline inner rim and a_ ultragranular hyaline
outer rim. The keel structure of double-keeled species
seems to be an important morphological feature that can
be used for unraveling their phylogeny.
Both the septal walls and tegilla of Globotruncana are
microgranular hyaline perforate (see Plate 95, fig. 13).
Globotruncana includes two phylogenetically and mor-
phologically distinct stocks: (1) The Globotruncana stuarti
s.s. lineage group (Text-figure 34) and (2) the Globo-
truncana fornicata—lapparenti—bulloides lineage group
(Textfigure 35). The Globotruncana stuarti lineage
eroup includes all species of Globotruncana having a single
keel throughout their ontogeny. Phylogenetic relationships
within this lineage group are indicated in Text-figure 34
and will be discussed in more detail under various specific
headings. The G. stuarti lineage group is a homogeneous
group and its phylogeny is easier to decipher. It evolved
in Early Campanian times probably from an Archacoglobi-
gerina blowi/cretacca stock via the peripheral angulation of
the latter form’s test and the acquisition of raised beaded
sutures. Assumedly, the A. blowi/cretacea ancestor from
which the G. stwarti group evolved lacked a double keel
and possessed only an imperforate peripheral band. An 4.
blowi/cretacea stage of development is often recapitulated
in the ontogeny of all members of this species plexus.
The Globotruncana fornicata—lapparenti—bulloides
lineage group includes all Globotruncana having a double
keel present at the nepionic and neanic stages of their
ontogeny. The double keel need not be present at all in the
GuLF CRETACEOUS FORAMINIFERA: PESSAGNO 31
last whorl. Some species such as Globotruncana rosetta
(Carsey) and Globotruncana stephensoni Pessagno, n. sp.
may occasionally show double keels only in the preceding
whorls. The double keel of specimens of these species be-
comes progressively narrower during their ontogeny and
finally merges to form a single keel before the last whorl.
As the name of this species group implies, it is a hetero-
geneous group which can be divided into a number of sub-
groups. Most of these subgroups arose from one of the name
species of this major lineage group. The subgroups are as
follows:
(1) Globotruncana fornicata subgroup: Includes all
of the species which evolved from a Globotruncana forni-
cata Plummer ancestor (Text-figure 35) .
(2) Globotruncana bulloides subgroup: Includes all
of the species which evolved from a Globotruncana bul-
loides Vogler ancestor. It is conceivable that Globotruncana
plummerae Gandolfi evolved from a G. bulloides ancestor
rather than from a G. fornicata ancestor. Such a supposition
needs further investigation.
(3) Globotruncana lapparenti s.s. subgroup: Includes
all species that evolved directly or indirectly from a G.
lapparenti s.s. stock. It is conceivable that the G. arca
(Cushman) branch of the G. fornicata subgroup stems
from G. lapparenti s.s. rather than from G. fornicata.
(4) Globotruncana gansseri subgroup: G. gansseri is
the only Maestrichtian species of Globotruncana that seems
to have evolved directly from a A. blowi stock. It is con-
ceivable that G. aegyptiaca Nakkady and G. duwi Nakkady
evolved from either a G. gansseri ancestor or a G. rosetta
(Carsey) ancestor as suggested in Text-figure 35.
It should be stressed again that the G. fornicata—
lapparenti—bulloides lineage group is a complex and he-
terogeneous species plexus and the phylogenetic relation-
ships suggested in Text-figure 35 are in many cases far
from certain. The phylogenetic relationship of each of the
species of Globotruncana shown in the Text-figure 35 will
be discussed in more detail under the specific headings to
follow.
A great reduction of the G. fornicata—lapparenti—bul-
loides lineage group occurred at the end of Early Maestrich-
tian (R. subcircumnodifer subzone) times (cf. ‘Text-figure
35). Most of the extinctions of species occurring at this time
were in the G. bulloides and G. lapparenti subgroups. The
G. fornicata subgroup persists with fewer changes.
The G. fornicata—lapparenti—bulloides lineage group
most likely originated from a double keeled Archaeoglobi-
gerina stock: A. blowi Pessagno, n. sp.—7A. cretacea (d’Or-
bigny) —>G. fornicata Plummer, G. bulloides Vogler, and
o
G. lapparenti s.s. Brotzen. The writer has noted numerous
transitional specimens between A. cretacca (d’ Orbigny)
and G. bulloides Vogler. At the moment, the writer does not
favor the orgin of these three basic early species of Globo-
truncana from Marginotruncana though admittedly this
possibility needs further investigation.
Range.—M. renzi assemblage zone?; G. bulloides assem-
blage zone to G. contusa-stuartiformis assemblage zone. Late
Coniacian?; Early Santonian to Late Maestrichtian.
World-wide. All
Occurrence.—Upper — Cretaceous.
faunal provinces.
Globotruncana aegyptiaca Nakkady
Plate 79, figures 2-4; Plate 83, figures 8-10; Plate 94, figure 6;
Plate 95, figures 8, 9
1950. Globotruncana aegyptiaca Nakkady, Jour. Paleont., vol. 24,
No. 6, p. 690, pl. 90, figs. 20-22.
1951. Globotruncana gagnebini Tiley, Lausanne Univ., Mus. Geol.,
Lab. Géol., Min., Geophys., Bull., No. 103, pp. 50-56, text-
figs. I4a-17d; pl. 3, figs.2a-5d.
1952. Globotruncana lamellosa Sigal, 19th Congr. Géol. International
Monogr. Rég., Alger., ser. 1, No. 26, p. 42, text-fig. 45 (3 figures).
1955. Globotruncana aff. cretacea Cushman, Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 62, pl. 4, figs. 7a-c.
1957. Globotruncana gagnebini Tilev, Bolli, U.S. Nat. Mus., Bull., No.
215, p. 59, pl. 14 figs. 5a-c.
1961. Globotruncana arca (Cushman), Said and Kerdany, Micropal-
eont., vol. 7, No. 3, p. 330, pl. 2, figs. 14a-c.
1964. Globotruncana gagnebini Tiley, Olsson, Micropaleont., vol. 10,
No. 2, p. 165, pl. 4, figs. 4a-c.
Description.—Test petaloid, trochospiral, usually plano-
convex with planiform spiral side and inflated, convex um-
bilical side; four to five angular conical chambers in last
whorl which gradually increase in size. Sutures curved both
spirally and umbilically; elevated, often highly beaded
spirally; elevated to slightly depressed umbilically. Umbili-
cal side of test often rugose or coarsely spinose. Narrow
double keel following spiral margin of test, sometimes
merging to form a single keel in last several chambers of
final whorl. Single keel visible in thin-section in preceeding
whorls (cf. Plate 95, figure 8). Primary aperture umbilical
in position, rather highly arched. Umbilicus deep, covered
by spiral system of tegilla with intralaminal and infrala-
minal accessory apertures on well-preserved specimens.
Outer wall radial hyaline perforate except for keel which
is mostly radial hyaline imperforate, but partly ultragranu-
lar hyaline imperforate (variety of type 2; Text-figure 40) .
Septal walls and tegilla microgranular hyaline finely and
sparsely perforate.
Remarks.—Globotruncana acgyptiaca Nakkady differs
from Globotruncana duwi Nakkady (1) by possessing a well-
520 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 27
9 ok
Globotruncana
aegyptiaca
Hypotype
PE 710
PE 70
2
3 3
aie: 0.063 J0.063 |0.092
et at
Ht. double |g 942 |o.04:
keel at D'
All measurements in millimeters.
oa Pap
.060)0.060
* Hypotype (Maestrichtian, of Egypt) from El-Naggar.
we D-D', = diameter of last whorl. Dp-D'}, - diameter of preceeding
whorl.
developed single-keeled early stage of development; (2) by
showing a much less rapid expansion in chamber size; (3)
by having lower T’X/TX values; and (4) by being some-
what less rugose and not showing well-developed ultra-
granular hyaline spines along the spiral rim of its keel. Pre-
liminary form analysis measurements for G. aegyptiaca are
presented in Text-figure 27. Text-figure 28 is a scatter plot
of T’X/TX values and D,—D’,/D,—D’,
acgyptiaca and G. duwit.
values for G.
Globotruncana gagnebini Tiley shares both nearly
identical morphological features and a similar geologic
range with Globotruncana aegyptiaca Nakkady. It clearly
represents a junior synonym of G. aegyptiaca.
The specimen figured by Gandolfi (1955) as Globo-
truncana atf. cretacea Cushman (No. 20852 PRI) from the
Upper
Cretaceous Colon formation of Columbia is also
TEXT-FIGURE 28
@ Globotruncana cegyptiaca Nakkody (1) = Hypotype of Globotruncana aegyptiaca
; a Globotruncana duwi Nakkady £ s. s. Nokkady from El-Naggar
‘ |
3.0
e
x &
S
~<
7
20+ ® q «
|
e e
e
2.
1.0 a= pe =< i — if =]
1.0 2.0 3.0 40 5.0
D, -D; /D,-Py,
referrable to G. aegyptiaca. Examination of this specimen at
the Paleontological Research Institution, Ithaca, New York,
reveals that it possesses a narrow double keel on the first
chamber of the last whorl which merges to form a single
keel on the subsequent chambers.
The phylogenetic relationship of G. aegyptiaca and
G. duwi to other species of Globotruncana is not clearly
understood at this time. These species may be related to
either G. rosetta (Carsey) or to G. gansseri Bolli as sug-
gested in Text-figure 35, It is also possible that they evolved
from the G. stuarti lineage group. The presence of a single-
keeled early stage (PI. 95, fig. 8) in G. aegyptiaca lends
strong support to this latter hypothesis. Berggren (1962, p-
59) believed “—that G. aegyptiaca has developed directly
from G. rosetta through modification in number and
height of chambers and development of a higher, more
acute umbilical collar.”
Range.—Globotruncana contusa—stuartiformis assem-
blage zone: G. gansseri subzone to A. mayaroensis subzone.
Occurrence.—In Mexico G. aegyptiaca occurs abundant-
ly in the upper part of the Méndez shale in strata assign-
able to the A. mayaroensis subzone (Text-figure 2). In
Texas, G. aegyptiaca has’ been observed in the Corsicana
Travis County (Onion Creek section) ,
Navarro County (“Corsicana Clay Pit” section) . It has been
observed in the Kemp clay in samples collected along the
bluffs of the Colorado River north of Garfield and also in
samples collected along the Brazos River near the Milam
and Falls County lines.
marl in and in
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 321
In southwestern Arkansas G. aegypliaca occurs abund-
antly in samples from the Arkadelphia marl.
Olsson (1964, loc. cit.) recently figured this species
under the name of G. gagnebini Vilev from essentially the
same horizon in New Jersey from the Shrewsby member of
the Redbank formation. The writer observed numerous
specimens of G. aegyptiaca in samples given to him by Dr.
H. Bolli from the Upper Maestrichtian (4. mayaroensts
subzone) portion of the Guayaguayare formation of ‘Trini-
dad.
G. aegyptiaca is also known from the Maestrichtian of
Egypt, Turkey, Libya, Algeria, and Colombia.
Globotruncana arca (Cushman)
Plate 79, figures 5-8; Plate 90, figures 6-8; Plate 96,
figures 7, 8, 17
1926. Pulvinulina arca Cushman, Contr. Cushman Lab. Foram. Res.,
vol. 2, pt. 1, p. 23, pl. 3, figs. la-c.
1927. Globotruncana arca (Cushman), Contr. Cushman Lab. Foram.
Res., vol. 3, pt. 1, p. 91, pl. 19, fig. 11.
1927. Globotruncana arca (Cushman), Cushman, Jour. Paleont., vol.
1, No. 2, p. 169, pl. 28, figs. 28a-c.
1931. Globotruncana arca (Cushman), Plummer (part), Uniy. Texas
Bull., 3101, p. 195-198, pl. 13, fig. 8, not figures 7, 9, 11.
1937. Globotruncana arca (Cushman), Glaessner, Moscow Univ.,
Studies Micropaleont., vol. 1, fasc. 1, p. 36, pl. 1, figs. 10a-c.
1946. Globotruncana arca (Cushman), Cushman (part), U.S. Geol.
Sur., Prof. Paper, No. 206, p. 150, pl. 62, figs. da-c; not 5a-c.
1951. Globotruncana arca (Cushman), Tiley, Lausanne Univ., Mus.
Géol., Lab Géol., Min., Géophys., Bull. No. 103, p. 57, text-figs.
18a-c; 19a-d.
1951. Globotruncana arca (Cushman), Bandy, Jour. Paleont., vol. 45,
No. 4, p. 509, pl. 75, figs. la-c.
1953. ? Globotruncana arca (Cushman), Hamilton, Jour. Paleont., vol.
Zip PP 2062325 pl29, figs. V-3°
1953. Globotruncana arca (Cushman), Subbotina, Trudy, Vses. Neft.
Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 185,
pl. 9, figs. la-5c; pl. 10, figs. la-5c.
1955. Globotruncana (Globotruncana) arca (Cushman), Dalbiez, Mi-
cropaleont., vol. 1, No. 2, p. 164, text-figs. 5a-c.
1955. Globotruncana arca arca (Cushman), Gandolfi, Bull. Amer,
Paleont., vol. 36, No. 155, p. 63, pl. 5, figs. 2a-4e.
1956. Globotruncana arca (Cushman), Bronnimann and Brown, Eclogae
Geol. Hely., vol. 48, No. 2, pp. 539, 540, pl. 23, figs. 10-12.
1957. Globotruncana (Globotruncana) arca (Cushman), Edgell
(part) , Micropaleont., vol. 3, No. 2, pp. 110, 111, pL. 3, figs. 4-6,
13, 14; not pl. 1, figs. 10-12.
1957. Globotruncana arca (Cushman). Bolli, et al., U.S. Nat. Mus.,
Bull, No. 215, p. 44, pl. 11, figs. 6-11C.
1960. Globotruncana leupoldi Bolli, Olsson, Jour. Paleont., vol. 34, No.
Pep oO; ple lily figs: 1-3:
1960. Not Globotruncana arca (Cushman). Klaus, Eclogae Geol. Helv.,
vol. 52, No. 2, p. 824, pl. 7, figs. 5a-c.
1962. ? Globotruncana maret Banner and Blow, Berggren, Stockholm
Cont. Geol., vol. 9, No. 1, pp. 54-56, pl. 9, figs. 5a-c.
1962. Globotruncana arca (Cushman), Berggren, Stockholm Contr.
Geol., vol. 9, No. 1, pp. 49-51, pl. 9, figs. la-2c.
1962. Globotruncana arca (Cushman), Barr, Paleontology, vol. 4, No.
4, pl. 69, figs. 8a-c.
1964. Globotruncana arca (Cushman), Loeblich and Tappan, Treatise
Invert. Paleont., pt. C, Protista 2, vol. 2, p. C662, fig. 529: la- 1b;
9
1964. Globotruncana arca (Cushman), Olsson, Micropaleont., vol. 10,
No. 2, pp. 162, 163, pl 4, figs. la-3c.
1964. Globotruncana arca (Cushman), Martin, Jahr. Geol. Bund.,
Sond: 9) p: 79) pl: 9), figs: 4a-c:
Description.—Test trochospiral, spiroconvex (mean
T’X/TX value 0.45 for six sectioned free specimens) with
six to seven (rarely eight) petaloid chambers in the final
whorl which gradually expand in size and show little or
no arching of spiral and umbilical chamber walls. Periphery
mildly lobulate; truncated by well-developed, beaded
double keel which tends to be inturned umbilically; last
chambers sometimes lacking keel. Sutures curved, raised
often heavily beaded spirally; slightly curved, raised um-
bilically and occasionally beaded. Umbilicus deep, rela-
tively broad, covered by spiral system of tegilla in well-
preserved specimens which have intralaminal and infrala-
minal accessory apertures. Primary aperture interiomar-
ginal, umbilical in position. Outer wall radial hyaline per-
forate except for keels which are radial hyaline, imper-
forate and ultragranular hyaline, imperforate. Septal walls
and tegilla microgranular hyaline, finely perforate.
(Cushman) — differs
from Globotruncana stephensoni Pessagno, n. sp. (1) by
possessing a wide double keel with equally developed spiral
Remarks.—Globotruncana arca
and umbilical rims rather than a single keel or a narrow
double keel with a poorly developed umbilical rim and (2)
by having chambers which are petaloid rather than sub-
trapezoidal in shape. Both species share a unique keel
structure which does not seem to exist in any other double
keeled species of Globotruncana s.s. Most double-keeled
species show double keel rim components which are pre-
dominantly radial hyaline and possess only ultragranular
hyaline outer layers. The radial hyaline inner element is
usually bulged out to form most of the keel rims (Text-
figure 40). However, the double keel structure of both G.
arca and G. stephensoni shows an umbilical rim which con-
sists of 85 to 100°/ ultragranular hyaline calcite (Plate 96,
figure 17; Text-figure 40, type 1). The spiral rim is of nor-
mal globotruncanid character and is dominantly radial
hyaline with a ultragranular hyaline outer layer.
Plummer (1931, pp. 195-198) included specimens now
clearly assignable to G. stephensoni Pessagno, n. sp. (pl. 13,
figs. 7a-c), G. elevata (Brotzen) (pl. 13, figs. 9a-c), and
G. rosetta (Carsey) (pl. 13, figs. la-c) in G. arca (Cush-
man) .
As noted by Bolli (1951, p. 196), Bronnimann and
Brown (1956, p. 540), Berggren (1962, p. 50), and various
other workers, Cushman (1946, p. 150) obscured the recog-
nition of this speceis by figuring a single-keeled specimen
of the Globotruncana stuarti lineage group [G. elevata
(Brotzen) pl. 62, figs. 5a-c] together with the double-
keeled holotype (pl. 62, figs. da-c). Unfortunately, a num-
322 PALAEONTOGRAPHICA AMERICANA (V, 37)
ber of other workers followed Cushman’s figures thus caus-
ing numerous erroneous identifications of G. arca in the
literature.
The specimen figured by Klaus (1960, p. 824, pl. 7,
figs. ba-c) as G. arca (Cushman) is probably assignable to
M. angusticarenata (Gandolfi). Abundant — stratigraphic
evidence from this study indicates that G. arca does not
occur in strata older than Early Campanian.
Form analysis data for sectioned Mexican and ‘Texas
specimens of G. arca (Cushman) are presented in Text-
figure 29.
Although Text-figure 35 suggests that G. arca (Cush-
man) arose from a G. fornicata Plummer stock, its origin
is still speculative and needs further investigation. The fol-
lowing hypotheses should be considered.
(1) G. arca arose from G. fornicata (a) through the
widening of the latter forms chambers spirally to yield a
petaloid shape and (b) through the reduction or loss of
the radial hyaline component comprising the umbilical rim
of the latter form’s double keel. The similar shape of the
chambers of both species umbilically, their similar T’X/TX
values, and the inturned nature of their double keels argue
for a phylogenetic link between these two species.
(2) G. arca (Cushman) arose from a G. lapparenti
Brotzen s.s. stock through the reduction of the radial hya-
line component comprising the umbilical rim of the latter
form’s double keel. Both species share relatively similar
chambers spirally and umbilically, have overlapping T’X/
‘TX values, and have similar keel heights at D and D’. Berg-
gren (1962, p. 50) believed that G. arca arose from a G.
lapparenti s.s. stock.
(3) G. arca (Cushman) arose from G. stuartiformis
Dalbiez through the acquisition of a secondary umbilical
rim comprised of ultragranular hyaline calcite, more peta-
loid chambers spirally, and a somewhat more spiroconvex
test.
At present, the writer favors these three hypotheses in
the order listed above with the first hypothesis being the
most likely and the third hypothesis being the least likely.
Some workers such as Dalbiez (1955, p. 164) suggested that
G. arca has been derived from G. lapparenti tricarinata
(Quereau) (=G. linneiana (d’Orbigny). The keel struc
ture of G. linneiana is radically different from that of G.
arca. ‘The changes in keel structure needed to perpetuate
this phylogenetic link are insurmountable (cf. Plate 96,
fics Plate 97, ties 12)).
‘The writer examined the holotype of G. arca on deposit
in the Cushman Collection at the U.S. National Museum,
Washington, D.C.
TEXT-FIGURE 29
Globotruncana
arca
(Cushman)
PE 805
TX 291-A
PE 881
TX 291-A
PE 883
TX 291-A
S)
nN
ipo)
tx [0.168 ]0.168 Jo.18
| rx [0-056 0.056 |o.04
ow ee
Nh
0.07
~-
i=)
co Wy
0.476
ibe)
S407 |BA%
N
Lee)
.
S)
°
Nm
e XDU
Angle XDT 3
xp |0.196 o. 2520.1
0
aX j0.33 Jo.ss fo.2s
He Sexb)e| o.o70[0.070]0.070] 0.
0.
ho
Wo
NO
NS
All measurements in millimeters.
* + = presence of double keeled early stage.
Range.—G. fornicata—stuartiformis assemblage zone,
A. blowi subzone (D. multicostata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence.—In Mexico G. arca (Cushman) is common
in the Campanian and Maestrichtian portions of the Mén-
dez shale and in the Early Campanian portion of the San
Felipe formation throughout the area of study (Text-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 323
figure 2). Cushman (1927, p. 23) in his original descrip-
tion of this species stated that its type locality is near
Huiches, Hacienda El Limon. With the help of S. R.
Santoyo (Tampico Office, Petroleos Mexicanos), the
writer found that Hacienda El Limon was a large ranch
that covered much of the country side somewhat east of
Tamuin (Guerrero). Furthermore, the Mexican natives
questioned in the area surrounding Tamuin indicated that
Huiches corresponds approximately to the place where the
highway from Tampico to Ciudad Valles crosses over the
Rio Huiches, 2.2 kilometers east of Tamuin (near Kilo-
meter Post K 101.0). Méndez samples (TYPE-1) collected
from a road cut immediately east of the highway bridge
over the Rio Huiches contained G. arca (Cushman) to-
gether with G. conica White, G. stuarti (de Lapparent)
s.s., A. mayaroensis (Bolli), G. gansseri Bolli, and other
species indicating a planktonic assemblage assignable to the
A. mayaroensis subzone. It is suggested that this locality
(TYPE-1) should hereafter be considered as the type
locality of G. arca (Cushman) .
G. arca (Cushman) has been observed in ‘Texas during
this study only in the “Upper Taylor marl” in ‘Travis and
Limestone Counties and in the Upson clay in Maverick
County. Bolli, et al., (1957, p. 46) noted this species in the
Corsicana marl near Noack, Williamson County, ‘Texas.
In southwestern Arkansas, G. arca has only been ob-
served in the upper part of the Ozan formation. Elsewhere
in North America G. arca s.s. is known from the Navesink
and Red Bank formations of New Jersey (cf. Olsson, 1964,
pp- 162, 163), by Bandy (1951, p. 509) from the Maestrich-
tian of the Carlsbad area, San Diego County, California,
and by Martin (1964, p. 79) from the Campanian Uhalde
formation of Fresno County, California. A number of refer-
ences are made of this species in the North American lit-
erature. A number of these need rechecking because of the
confusion surrounding the morphological characteristics
of this taxon.
In Eurasia G. arca (Cushman) is known from the
Maestrichtian of Denmark, Russia, Italy, and the Cam-
panian and Maestrichtian of France. It is also known from
the Maestrichtian of Turkey and Cuba and the Late
Campanian and Maestrichtian of Australia, Tunisa, Trini-
dad, and Colombia.
G. arca seems to be equally common in both the Boreal
and Tethyan faunal province during the Early Campan-
ian—Maestrichtian time interval. It is one of the few double-
keeled species that bridge the period of extinctions that oc-
curred at the end of Early Maestrichtian time (R. subcir-
cumnodifer subzone) .
Globotruncana austinensis Gandolfi
Plate 82, figures 12-15; Plate 94, figure 9
1955. Globotruncana marginata austinensis Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 29, pl. 1, figs. 6a-c.
196. Globotruncana aff. G. gagnebini Tilev, Olsson, Micropaleont.,
vol. 10, No. 2, pl. 4, figs. 6a-c.
Description.—Test trochospiral, deeply umbilicate,
slightly lobulate with four or five angular truncate cham-
bers in last whorl; double keel following periphery of last
whorl; wider in early chambers of last whorl, becoming
narrower and migrating to spiral periphery as subsequent
chambers are added; may merge to form a single keel.
Spiral side slightly convex; not truly planiform because of
vaulted nature of individual chambers spirally; early whorl
sometimes (cf. Pl. 94, fig. 9) depressed. Umbilical side con-
vex (mean T’X/TX value for three measured specimens=
1.99) with curved somewhat depressed beaded sutures. Or-
namentation consisting of occasional rugosities on spiral
side; umbilical side often showing rugosites oriented at
random on surface of first several chambers of last whorl.
Primary aperture interiomarginal, umbilical in position.
Umbilicus covered by spiral system of tegilla with both
intralaminal and infralaminal accessory apertures. Outer
wall radial hyaline, perforate except for keels which are
both radial hyaline, imperforate and ultragranular hyaline,
imperforate (cf. type 2, Text-figure 40). Tegilla and septal
walls microgranular hyaline, finely perforate.
Remarks.—G. austinensis Gandolfi is closely related to
G. bulloides Vogler and appears to be gradational into this
latter species. It can be separated from G. bulloides (1) by
the greater convexity of its umbilical side (mean T’X/TX
value—1.99 for 3 measured specimens) ; (2) by the position
of its keel along the spiral margin of the test; and (3) often
by the depressed nature of its early whorls. Both species
show vaulted spiral and umbilical chamber walls and a
generally similar chamber arrangement. The vaulted na-
ture of the chambers, depressed early whorl, and the highly
convex umbilical side of this species are well illustrated
by the sectioned specimen in Plate 94, figure 9 herein.
Form analysis measurements of the three specimens of
G. austinensis sectioned are shown in Text-figure 30. Text-
figure 31 is a scatter plot comparing D-D’ and T’X/TX
values of G. austinensis, G. bulloides, and G. lapparenti s.s.
Until further specimens of G- austinensis are sectioned it is
suggested that T’X/TX=1.5 be considered as the upper
limit of G. bulloides and that T’X/TX=1.6 be considered
the lower limit of G. austinensis; and that all specimens
having T’X/TX values greater than 1.5 and less than 1.6
be considered transitional forms.
The holotype of G. marginata austinensis Gandolfi
(No. 20828) was examined at the Paleontological Research
Institution at Ithaca, New York. The holotype corresponds
well with the description given above. It shows, for ex-
ample, a narrow double keel following the spiral periphery
of the test, depressed early whorls, and a quite convex um-
bilical side. Although Gandolfi (1955, p. 29) inferred that
this species is related to M. marginata (Reuss), the holo-
type shows a primary aperture which is umbilical in posi-
tion rather than extraumbilical-umbilical in position. In
addition, the general form of its test is completely unlike
that of M. marginata (Reuss) .
Range.—G. bulloides assemblage zone to G. fornicata—
stuartiformis assemblage zone, R. subcircumnodifer subzone
(R. subpenny? zonule) .
Occurrence.—G. austinensis occurs in the Campanian
and Lower Maestrichtian portions of the Méndez shale of
Mexico. It has been observed in Texas in the Austin chalk
(rare), “Lower Taylor marl”, Wolfe City sand, and Ney-
landville marl. In southwestern Arkansas it occurs in the
Marlbrook marl and in the Saratoga chalk.
The specimen figured by Olsson (1965, pl. 4, figs.
6a-c) from the Mt. Laurel formation of New Jersey as G.
aff. G. gagnebini is referrable to G. austinensis.
Gandolfi originally described this species from the
Colon formation of Colombia. The writer has observed it
in Late Campanian to Early Maestrichtian samples from the
Rio Yauco formation and Parguera limestone of Puerto
Rico. All of the specimens referred to by Pessagno (1960,
1962) as G. tricarinata (Quereau) should be assigned to
G. austinensis Gandolfi.
Globotruncana bulloides Vogler
Plate 64, figures 15-17; Plate 67, figures 1-3; Plate 73, figures
9, 10; Plate 75, figures 4-8; Plate 97, figures 14, 15
1931. Globotruncana canaliculata (Reuss) var. ventricosa White, Plum-
mer, Univ. Texas Bull. 3101, p. 199, pl. 13, figs. 10a-b.
1941. Globotruncana linnei (d’Orbigny) subsp. bulloides Vogler, Pal-
aeontographica, Suppl. Bd. 4, Abt. 4, p. 287, pl. 23, figs. 32-39.
(Lectotype designated herein; pl. 23, fig. 33.)
1944. ? Globotruncana lapparenti bulloides Vogler, Bolli, Eclogae
Geol. Helv., vol. 37, No. 2, pp. 231, 232, text-figs. 17, 18; pl. 9,
fig. 12.
1946. Globotruncana marginata (Reuss), Cushman (part), U.S. Geol.
Sur., Prof. Paper, No. 206, p. 150, pl. 62, figs. 2a-c; not la-c.
1951. Globotruncana lapparenti bulloides Vogler, Bolli, Jour. Paleont.,
vol. 25, No. 2, pp. 190, 194, fig. le.
1953. Globotruncana ventricosa White, Subbotina, Trudy, Vses, Neft.
Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 194, pl
13, figs. la-c; 2a-c; 3a-c; 4a-c.
1955. Globotruncana bulloides bulloides Vogler, Gandolfi, Bull. Amey.
Paleont., vol. 36, No. 155, p. 32, pl. 1, figs. 9a-c.
1957. Globotruncana marginata (Reuss) , Edgell, Micropaleont., vol. 3,
No. 2, p. 114, pl. 2, figs. 4-6.
1957. Globotruncana marginata (Reuss), Sacal and Debourle (part),
Soc. Géol. France, (n. sér.), Mém. No. 78, p. 59, pl. 26, figs. 5,
12; not 3; not 13
1957.
1962.
1962.
)
PALAEKONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 30
©
G
ise}
12)
G
5)
Hu
os)
°o
QQ
°
ce
oO
austinensis
Gandolfi
TX 291-C
Ht. double 0.042
keel at De
All measurements in millimeters.
Not Globotruncana bulloides Vogler, Sacal and Debourle, Soc.
Géol. France, n. sér., Mém. No. 78, p. 62, pl. 26, figs. 2, 4, 19, 20.
Globotruncana marginata (Reuss), Herm, Bayer. Akad. Wiss.
Math.—Nat. K1., Abh., n. ser., No. 104, pp. 85, 86, pl. 5, fig. 5.
Globotruncana lapparenti bulloides Vogler, Herm, Bayer. Akad.
Wiss. Math.—Nat. KI., Abh., n. ser., No. 104, pp. 84, 85, pl. 6,
fig. 6.
GuLF CRETACEOUS FORAMINIFERA: PESSAGNO 325
1962. Globotruncana globigerinoides Brotzen, Herm, Bayer. Akad.
Wiss. Math.—Nat. KI. Abh., n. ser., No. 104, pp. 80, 81, pl. 5,
fig. 6.
1962. Globotruncana marginata (Reuss), Barr (part), Paleontology,
vol. 4, pt. 4, pl. 70, figs. 3a-c; not pl. 72, figs. 7, 8a-c.
1962. Globotruncana culverensis Barr, Paleontology, vol. 4, pt. 4, pp.
569, 570, pl. 71, figs. la-c.
1962. Globotruncana (Globotruncana) lapparenti bulloides Vogler,
Pessagno, Micropaleont., vol. 8, No. 3, p. 360, pl. 6, figs. 13-14.
1964. Globotruncana linneiana (d’Orbigny), Olsson (part), Micro-
paleont., vol. 10, No. 2, p. 166, 167, pl. 7, figs. 7a-c; not 6a-c;
8a-c.
1964. Globotruncana fresnoensis Martin, Jahrb. Geol. Bund. Sond. 9,
p- 80, pl. 9, figs. 8a-c; not 8d.
1964. Globotruncana paraventricosa (Hofker), Martin, Jahrb. Geol.
Bund. Sond. 9, p. 81, pl. 10, figs. 4a-c.
Emended definition.—Test trochospiral, deeply umbili-
cate, biconvex with five to seven chambers in last whorl.
Larger microspheric form (PI. 64, figs. 15-17) with more
numerous chambers which gradually expand in size; smaller
megalospheric form (PI. 67, figs. 1-3; Pl. 75, figs. 4-8; PI.
97, figs. 14, 15) with fewer chambers which expand in size
more rapidly. Chambers highly vaulted both spirally and
umbilically; separated by curved, raised, often highly beaded
sutures. Spiral chambers sometimes possessing a few imper-
forate discontinuous costellae which are deep-seated struc-
turally, comprised of ultragranular hyaline calcite, and tra-
verse entire outer wall (PI. 97, fig. 14). Well-developed
double keel following periphery of test and tending to be-
come narrower as coiling progresses, often forming a single
keel on larger microspheric individuals (PI. 64, figs. 15-17) .
Primary aperture interiomarginal, umbilical in position.
Umbilicus covered by a spiral system of tegilla showing in-
fralaminal and intralaminal accessory apertures. Outer wall
radial hyaline perforate except for double keels which are
primarily radial hyaline imperforate, but possess secondary
ultragranular hyaline imperforate outer rim components
(type 2, Text-figure 40) ; secondary ultragranular compon-
ents of double keel lacking in last one or two chambers of
final whorl. Septal walls and tegilla microgranular hyaline,
finely perforate.
Remarks.—Vogler (1941, p. 287) originally described
Globotruncana linnei (A’Orbigny) subsp. bulloides Vogler
in syntypic series from the Senonian and Maestrichtian of
Indonesia. Unfortunately all of Vogler’s syntypes are draw-
ings of specimens encountered in rock thin-section. To
avoid further confusion concerning the identification of
this taxon, figure 33 of Vogler (1941) is designated the
lectotype of G. linnei bulloides Vogler and figure 34 of
Vogler (1941) is designated the paralectotype of G. linnei
bulloides Vogler. Several of Vogler’s syntypic figures (figs.
35, 38, 39) can be correlated with G. linneiana (d’Or-
bigny). Of the remaining figures, figure 36 probably rep-
TEXT-FIGURE 31 1 Globotruncana lapporenti s. s. Brotren
Figure n, de Lapporent, 1918, Lectotype
selected herein
2 = Globotruncona lopporenti ss, Brotzen
©+@= Duplicote or near duplicate measurement (Figure m; de Lopporent, 1918, Poralecto
@ = Globotruncona lapporenti s.s. Brotren type)
© = Globotruncana bulloides Vogler 3 = Globotruncana bulloides Vogler, 1941, pl
A= Globotruncano austinensis Gandolf 23, fig. 33
0.600 T= a we. 268 4 Three duplicote megsyrements.
°
a
e
= e
).500 ° oc)
=
= e
2 °
aR
a e
0.3 4
e e2 © : 4
1
°
0.400 bs 2
>
e ®,
°
e
e
0.3091 — a+ -— —
0.50 10 F 15 2.0
T X/TX
resents G. bulloides as emended herein; figure 32 can be
probably assigned to A. cretacea (d’Orbigny) ; and figure 37
is of uncertain specific assignment.
To establish the external morphology of G. bulloides
Vogler, a number of free specimens believed by the writer
to correspond to G. bulloides were thin-sectioned and com-
pared to the lectotype selected herein (cf. Pl. 97, figs. 14,
15). The specimens figured in Plate 67, figures 1-3; Plate 73,
figures 9, 10; and particularly those in Plate 75, figures 4-8
correlate well with the sectioned lectotype. ‘These specimens
and the selected lectotype seem to represent the megalo-
spheric individual. The specimens illustrated in Plate 64,
figures 15-17 and by Barr (1962, pl. 71, figs la-c) as G.
culverensis Barr seem to represent the microspheric indi-
vidual. The megalospheric form possesses about two whorls
of chambers which rapidly increase in size. There are
usually five chambers in the final whorl with a double keel
following the periphery and becoming somewhat narrower
as subsequent chambers are added. The microspheric form
possesses three whorls of chambers which gradually increase
in size. There are usually six to seven chambers in the final
whorl, truncated peripherally by a double keel which nar-
rows to form a single keel on the last one or two chambers.
The double keel structure of G. bulloides is strength-
ened by the accretion of a secondary ultragranular calcite
layer on its spiral and umbilical rims over a radial hyaline
base (type 2, Text-figure 40). This layer is not present in
the newly formed chambers which usually possess either a
radial hyaline imperforate peripheral band or a weakly
developed radial hyaline double keel.
326 PALABKONTOGRAPHICA AMERICANA (V, 37)
Numerous authors such as Cushman (1946, pl. 62,
figs. 2a-c), Edgell (1957, pl. 2, figs. 4, 5), and others have
confused M. marginata (Reuss) with G. bulloides Vogler.
bulloides differs from M. marginata (1) by possessing
a umbilically situated primary aperture rather than an
aperture; (2) by
spiral system of tegilla with intralaminal and infralaminal
extraumbilical-umbilical possessing a
accessory apertures instead of stout portici with infralaminal
(3) by being deeply umbilicate; (4) by
having curved raised sutures instead of straight, depressed
accessory apertures;
sutures umbilically;
veloped, wider (higher) double keels (cf. heights of double
keels in Text-figures 21 and 32) which are both radial
and (5) by having more strongly de-
hyaline and ultragranular imperforate. G. bulloides is
both phylogenetically and morphologically unrelated to
M. marginata (Reuss) .
Globotruncana culverensis Barr (1962) and Globo-
truncana fresnoensis Martin (1964) are regarded as junior
synonyms of G. bulloides Vogler as they appear to fall
within the morphological variation allowable for this spe-
cies.
Text-figure 32 shows form analysis data for 12 sec-
tioned specimens of G. bulloides Vogler. Text-figure 31 is
a scatter plot comparing T’X/TX values and D-D’ values
of G. lapparenti Brotzen s.s., G. bulloides Vogler, and G.
austinensis Gandolfi. T’X/TX values
greater than 0.9 and less than 1.0 are considered transitional
between G. lapparenti s.s. and G. bulloides. Specimens hay-
ing T’X/TX values greater than 1.5 and less than 1.6 are
considered transitional between G. bulloides Vogler and G.
austinensis Gandolfi.
Specimens having
As suggested in Text-figure 35, G. bulloides probably
arose from a double-keeled Archaeoglobigerina ancestor.
‘Transitional forms seem to occur between A. cretacea (d’Or-
bigny) and G. bulloides. It is likely that G.
arose from 4. cretacea through the acquisition of a more
strongly developed double keel and the vaulting of spiral
and umbilical chamber surfaces. It is also possible that G.
bulloides is derived from a G. lapparenti ancestor through
an increase in the convexity of the latter form’s umbilical
side.
Range.—G. bulloides assemblage zone, M. concavata
subzone to G. fornicata—stuartiformis assemblage zone, R.
subcircumnodifer subzone (R. subpennyi zonule) .
bulloides
Occurrence.—In Mexico G. bulloides occurs in numer-
ous localities in the Santonian and Early Campanian por-
tions of the San Felipe formation and in the Early Cam-
panian to Early Maestrichtian portions of the Méndez
shale (Text-figures 1, 2). In Texas it occurs throughout
TEXT-FIGURE 32
Globotruncana
bulloides
Vogler
Vogler 1941 *
23
0.245 J0.224 0.205 |0, 252
e cee Gale
89 10.084 |0 sae Jo-0e4| 0.112) 0.098]0.070 jo. 084 jo. 084 0.070
ss perferf
i oh
0.168 JO. 0.154] 0.224
0.252 40.2 ie
“fo she foo fx sfx bh
pra
° S
: f=} °
=
r)
Ht. double
keel at D
Ht. double
keel at D'
All measurements in millimeters.
* Selected Lectotype. Vogler 1941, pl. 23, fig. 33
** Like G. culverensis Barr (1962)
the Santonian portion of the Austin chalk in Kinney, Tra-
vis, McLennan, and Dallas Counties (Text-figures 1, 2). It
also occurs in the Early Campanian (Taylorian) (re-
worked) portion of the Austin chalk in the Dallas area. It
occurs throughout the Campanian Taylor formation: in
the “Lower Taylor marl” of Travis, McLennan, and Dallas
Counties; in the Wolfe City sand in McLennan County; in
the Pecan Gap chalk of McLennan County; and in the
Upper ‘Taylor marl” of Travis and Limestone Counties. It
also has been observed in the Upson clay in Maverick
County and in the Neylandville marl of Navarro County.
In southwest Arkansas G.
town marl,
bulloides occurs in the Browns-
the Ozan formation, the Annona chalk, the
Marlbrook marl, and the Saratoga chalk.
bulloides occurs in the Upper Cretaceous of New
Jersey, California, Puerto Rico, Trinidad,
Colombia, and Venezuela.
Panama,
It occurs abundantly in the Upper Cretaceous of Eu-
rope, North Africa, the East Indies, and Australia.
Globotruncana calcarata Cushman
Plate 64, figures 18-20; Plate 72, figures 5, 6; Plate 93, figure
14; Plate 94, figure 8
1927, Globotruncana calcarata Cushman, Contr. Cushman Lab, Foram.
Res., vol. 3, pt. 2, p. 115, pl. 23, figs. 10a, b.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 327
1928. Globotruncana calcarata Cushman, White, Jour. Paleont., vol.
2, No. p. 285, pl. 38, figs. 6a-c.
1933. Globotruncana calcarata Cushman, Cushman, Cushman Lab.
Foram. Res., Spec. Publ. 5, pl. 35, figs. 14a-c. [no pagination]
1946. Globotruncana calcarata Cushman, Cushman U.S. Geol. Sur.,
Prof. Paper No. 206, pp. 151, 152, pl. 62, figs. 8a-c.
1948. Globotruncana calcarata Cushman, Bartenstein, Soc. Géol.
France, Comptes rendus, No. 12, p. 244, text-figure 1.
1948. Globotruncana calcarata Cushman, Cushman, Maryland Dept.
Geol. Mines, Water Res., Bull., No. 2, p. 266, pl. 26, figs. 3a, b.
1949. Globotruncana calcarata Cushman, Wicher, Mus. Hist. Nat.
Pays Serbe, Ser. A-2, p. 90, pl. 5, fig. 17.
1951. Globotruncana (Globotruncana) calcarata Cushman, Noth, Jahrb.
Geol. Bud., Sond. 3, p. 78, pl. 8, figs. I4a-c.
1952. Globotruncana calcarata Cushman, Reiss, Res. Council Israel,
Bull., vol. 2, No. 3. p. 270, text-figs. la-c.
1952. Globotruncana calcarata Custiman, Sigal, 19th Congr. Géol.
Internat., Monogr. Rég., Alger ser. 1, No. 26, p. 39, text-fig. 43.
1953. Globotruncana calcarata Cushman, Hamilton, Jour. Paleont., vol.
Bil. INO. Ze [oy CRs jal ah woech Er Be
1953. Globotruncana calcarata Cushman, Schweighauser, Schweizer.
Palaeont., Abh., vol. 70, p. 13, pl. 10, fig. 9.
1954. Globotruncana calcarata Cushman, Ayala, Assoc. Mex. Geol.
Petrol., Bol., vol. 6, p. 385, pl. 2, figs. 3a-c.
1956. Rugotruncana calcarata (Cushman), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, pl. 23, figs. 1-3.
1957. Globotruncana calcarata Cushman, Sacal and Debourle, Mém.
Soc. Géol. France (n. sér.), Mem. 78, p. 60, pl. 28, fig. 4; pl. 27,
fig. 21.
1959. Globotruncana calcarata Cushman, Olvera, Univ. Nacional Aut.
Mex., Facultad de Ciencias, Dept. Biologia, Tesis Prof., pp. 38,
39, pl. 7, figs. 11-14.
1959. Rugotruncana calcarata (Cushman), Ayala, Univ. Nacional Aut.
Mexico, Instit. Geol., Paleont. Mexicana, No. 4, p. 27, pl. 7, fig. 2.
1962. Globotruncana calcarata Cushman, Herm, Bayer. Akad. Wiss.,
Abh., No. 104, pp. 67-68, pl. 6, fig. 3.
1963. Rugotruncana calcarata (Cushman), Bronnimann and Rigassi,
Eclogae Geol. Helv., vol. 56, No. 1, pl. 17, figs. la-c.
1963. Globotruncana (Globotruncana) calcarata Cushman, Van Hinte,
Jahrb. Geol. Bud., Sond. 8, p. 74, pl. 5, fig. 3.
1964. Globotruncana calcarata Cushman, Olsson, Micropaleont., vol. 10,
No. 2, p. 163, pl. 5, figs. la-c.
Description —Test trochospiral, planoconvex with six
to seven chambers in last whorl; single-keeled in all but
embryonic stage of development. Periphery with well-
developed, distinctive tubulospines extending out along
sutural extensions. Spiral side planiform to somewhat con-
cave; sutures spirally radial, straight, elevated often beaded.
Umbilical side highly convex and sometimes rugose; rugo-
sities not oriented in meridorial pattern. Sutures depressed,
straight to slightly curved umbilically. Umbilicus deep, cov-
ered by a spiral system of tegilla with intralaminal and in-
fralaminal accessory apertures on well preserved specimens.
Primary aperture interiomarginal, umbilical in position.
Outer wall radial hyaline perforate except for keels which
are radial hyaline imperforate and rugosities which are ul-
tragranular hyaline imperforate. Septal wall and_tegilla
microgranular hyaline finely perforate. Pore frames hex-
agonal in shape; relatively small (cf. Plate 94, fig. 8).
Remarks.—This is unquestionably one of the most dis-
tinctive species of Globotruncana. Few workers can fail to
recognize it.
The tubulospines characterizing this species are present
TEXT-FIGURE 33
Globotruncana
calcarata
Cushman
PE 656
TX 291-A
Ayala 1959
PE 657
TX 291-B
[e)
NI
i)
ee)
Ho S
Daa |
Ss
[e) (os)
(o) ine)
N [ee]
(oe) jo)
fe) ()
(js) (es)
iCal bho
[op) ho
[e) [e)
(2) (ee)
~ oO
un jo)
je)
paar
Ne)
fom
je)
i
NO
s
(Ss)
N
a
S
wm
oO
°
Oo
Oo
(o)
°
Angle DIU : 5
ia
Oo
oO
°
rOe
All measurements in millimeters.
both in the neanic and ephebic stages of development. The
specimen illustrated in Plate 94, (fig. 8) shows three whorls
of chambers with tubulospines clearly developed in the last
whorl and next to last whorl, but not in the first whorl.
Form analysis measurements for three sectioned speci-
mens of G. calcarata are shown in Text-figure 33. The high
T’X/TX values of G. calcarata seem to indicate that it is
closely related to G. elevata (Brotzen). It is likely that G.
calcarata evolved from a G. elevata ancestor as suggested in
Text-figure 34.
328 PALAEONTOGRAPHICA AMERICANA (V, 37)
3ronnimann and Brown placed G. calcarata in Rugo-
truncana Bronnimann and Brown because of the rugose
nature of its chambers umbilically. These rugosities on the
umbilical side of its test show no alignment in a meridorial
pattern. The writer restricts Rugotruncana to only those
species such as Rugotruncana subcircumnodifer (= R.
tilevi Bronnimann and Brown) having rugosities arranged
in a meridorial pattern.
Range.—G. fornicata—stuartiformis assemblage zone;
G. elevata subzone; G. calcarata zonule. This is the shortest
ranging species of Globotruncana s.s. in the Upper Creta-
ceous.
Occurrence.—G. calcarata occurs in the Upper Campan-
ian portion of the Méndez shale of Mexico. During the
course of this study it has been found in the “Upper ‘Taylor
marl” in Limestone County, Vexas and in the Annona chalk
of Sevier County, Arkansas. Cushman (1927) originally des-
cribed G. calcarata from the Pecan Gap chalk of Collin
County, Texas. In 1946, Cushman (p. 152) recorded its
occurrence from the Neylandville marl, “Upper ‘Taylor
marl”, Pecan Gap chalk, Wolfe City sand, Annona chalk,
and “Lower Taylor marl”. Extensive sampling of the Uppei
Cretaceous section of Texas in the course of this study in-
dicates that Cushman’s records are most likely in part er-
roneous. Numerous samples collected from the “Lowei
Taylor marl” in Travis, McLennan, and Dallas Counties
show no occurrences of G. calcarata. Occurrences in the
Wolfe City sand are possible, but have not been recorded
in the few samples from this unit collected during this
study. Beall (1964, p. 10) believed that the “Upper ‘Taylor
marl” is indistinguishable from the Neylandville marl in
east central Texas and that the term “Upper Taylor marl”
should be suppressed and included under the term Ney-
landville marl. Furthermore, Beall (cbid., p. 10) believed
that the contact between the Navarro group and the Taylor
group should be placed at the base of the Nacatoch sand.
In light of Beall’s findings Cushman’s record of G. cal-
carata could be interpreted as an occurrence in the Cam-
panian portion of the Neylandville marl.
Olsson recorded this species from the Upper Cam-
panian Marshalltown formation of New Jersey. The writer
has seen specimens of G. calcarata in thin-sections of lime-
stones from the Late Campanian of Panama. It occurs
in the Late Campanian of Cuba, Haiti, and in reworked
Campanian deposits in Trinidad. In Puerto Rico G. cal-
carata occurs in samples PR 2427 and PR 2121 from the
Parguera limestone and in sample PR 6 from the Rio
Yauco mudstone though it was not recorded by Pessagno
(1960, p. 91, chart 2).
Sacal and Debourle (1957, p. 60, pl. 28, fig. 4) figured
G. calcarata from the Upper Campanian of the Aquitaine
Basin of France. Dalbiez (1959, p. 865) indicated that
the Campanian of France is divided into the following
ammonite zones: (1)
assemblage zone; (2) the Delawarella delawarensis assem-
blage zone; (3) the Hoplitoplacenticeras vari assemblage
zone; and (4) the upper Bostrychoceras polyplocum assem-
blage zone. He noted further that the range zone of G. cal-
carata falls within the limits of the Bostrychoceras poly p/o-
cum assemblage zone. Although there has been considerable
dispute concerning the position of the Campanian—Maestri-
chtian boundary, the majority of French paleontologists
appear to favor the B. polyplocum assemblage zone as being
the uppermost zone of the Campanian. In addition to
its occurrence in France, G. calcarata occurs throughout the
Late Campanian of Europe. It is also known from the
Campanian of Israel, Algeria, Tunisia, and in the mid-
the lower Placenticeras bidorsatum
Pacific guyot area.
Globotruncana conica White
Plate 65, figures 8-10; Plate 82, figures 1-5; Plate 93,
figures 12, 13
1928. Globotruncana conica White, Jour. Paleont., vol. 2, No. 4, p. 285,
pl. 38, figs. 7a-c.
1946. Globotruncana conica White, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 151, pl. 61, figs. 20a-c.
1951. Globotruncana conica White, Bolli, Jour. Paleont., vol. 25, No. 2,
p- 196, pl. 34, figs. 13-15.
1951. Globotruncana conica White, Tilev, Lausanne Univ., Mus. Géol.,
Lab. Géol., Min., Géophys., Bull., No. 103, pp. 67-71, text-figs.
22a-d.
1951. Globotruncana conica caliciformis Tiley, Lausanne Univ., Mus.
Géol., Lab. Géol., Min., Géophys., Bull., No. 103, pp. 71-75, pl. 3,
figs. 6a-d.
1953. Not Globotruncana conica White, Subbotina, Trudy, Vses. Neft.
Naukno—Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 192,
pl. 11, figs. la-2c.
1955. Globotruncana stuarti conica White, Gandolfi,
Paleont., vol. 36, No. 155, p. 65, pl. 5, figs. 8a-c.
1956. Globotruncana conica White, Said and Kerdany, Micropalcont.,
vol. 2, No. 2, p. 150, pl. 5, figs. 16a-c.
1957. Not Globotruncana conica White, Sacal and Debourle, Soc.
Géol. France, n. sér., Mém., No. 78, p. 59, pl. 27, figs. 9, 16.
1959. Globotruncana conica White, Olvera, Univ. Nacional Aut. de
Mexico, Fac. Ciencias, Dept. Biol., Tesis Prof., pp. 41-43, pl. 8,
figs. 1-3.
1961. Globotruncana esnehensis Nakkady, Said and Kerany, Micro-
paleont., vol. 7. No. 3, p. 331, pl. 2, figs. 12a-c.
1962. Not Globotruncana conica White, Pessagno, Micropaleont., vol
8, No. 3, p. 362, text-figure 4; pl. 4, figs. 13, 14.
Bull. Amer.
Description.—Test trochospiral, spiroconvex with mean
T’X/TX value of 0.281 for 12 measured specimens; single-
keeled except in embryonic stage of development. Chambers
angular rhomboid; trapezoidally to subtrapezoidally shaped
both spirally and umbilically; sutures straight to slightly
curved, radial, elevated, often highly beaded both spirally
and umbilically. Umbilicus deep, usually surrounded by
|
il
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 329
beaded rim; covered by spirally arranged system of tegilla
with intralaminal and infralaminal accessory apertures in
well-preserved specimens. Primary aperture, interiomargi-
nal, umbilical in position. Outer wall radial hyaline, per-
forate except for keel which is radial hyaline imperforate
and beads or rugosities which are ultragranular hyaline,
imperforate. Tegilla and septal walls microgranular hya-
line, finely perforate.
Remarks.—G. conica White is similar to G. stuart: (de
Lapparent) s.s. It differs from the latter species chiefly by
the highly sp'roconvex nature of its test. G. conica, as noted
above, has a mean I’X/TX value of 0.281 whereas G.
stuarti s.s. has a mean T’X/TX value of 0.79 (Table 2).
Text-figure 36 shows form analysis data for sectioned speci-
mens (predominantly free specimens) of G. conica. The
means and standard deviations of these measurements are
tabulated in Table 2. Text-figure 37 is a scatter plot of
T’X/TX to D-D’ for G. conica and G. stuarti. The writer
arbitrarily separates these species at 1.5 standard deviations
for T’X/TX. Hence, specimens having a T’X/TX value
greater than 0.45 and less than 0.58 are termed transitional.
G. conica appears to have evolved from G. stuart: (de
Lapparent) s.s, through the arching of the spiral side of
the latter form’s test (Text-figure 34). Both species in thin-
section often show the development of wide radial hyaline
imperforate bands below the keel in the outer walls of
chambers umbilically. These radial hyaline imperforate
bands only develop in the early whorls of the test of both
species and never occur in the final whorl. The writer be-
lieves that porous portions of the test present in these early
whorls have been reconstituted and made imperforate at
some time during the secretion of the final whorl of the test.
Such a reconstitution of the early test wall occasionally
occurs among other species of the Globotruncana stuarti s.s.
lineage group but is most prevalent with G. stuarti s.s. and
G. conica.
The specimens referred to G. conica White by Pessagno
(1962) in text-figure 4 and in pl. 4 (figures 13, 14) are
assignable to G. stephensoni Pessagno, n. sp. and G. sp.
respectively. As noted elsewhere, G. stephensoni may be
nearly homeomorphic for G. conica or G. stuarti s.s.
The specimen of G. conica White figured by Olvera
(1959, pl. 8, figs. 1-3) probably represents a contaminant.
Through the kindness of F. Bonet (Petroleos Mexicanos)
the writer obtamed numerous samples of Méndez shale
from well Bustos No. 1. No specimens of G. conica White
were recorded from the 1223.5—1250.0 meters interval al-
though G. stephensoni Pessagno, n. sp. was recorded in a
Late Campanian assemblage from this horizon. However,
—
©
an ew 2 | Text — Figure 34 Phylogeny of Globotruncana
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it should be pointed out the Late Campanian and Early
Maestrichtian portions of the Méndez shale were reworked
to varying degrees during Late Maestrichtian (4. maya-
roensis subzone times. Olvera’s specimen could represent
such a Late Maestrichtian element in a slightly reworked
Late Campanian fauna.
Dr. John Imbrie, Department of Geology, Columbia
University has informed the writer that the holotype of
G. conica White is missing in the White Collection housed
in Columbia University’s paleontology collections. If the
holotype cannot be located in the next several years, a
neotype should probably be erected.
Range.—G. contusa—stuartiformis assemblage zone:
G. gansseri subzone (upper part) to A. mayaroensis sub-
zone.
330 PALAEONTOGRAPHICA AMERICANA (V, 37)
Occurrence.—G. conica White occurs abundantly in the
Late Maestrichtian (A. mayaroensis subzone) portion of
the Méndez shale in the Tampico area of Mexico. Its precise
range zone like that of many Maestrichtian species in this
area of Mexico has been obscured by the fact that the Late
Campanian and Early Maestrichtian portions of the Men-
dez shale were reworked to varying degrees during Late
Maestrichtian (A. mayaroensis subzone) times. White
(1927, p. 317) showed G. conica extending well down into
the Campanian portions of the Méndez (includes Papa-
gallos of White also) and even down into the San Felipe.
Although his San Felipe occurrences of G. conica either
represent misidentifications or contaminants from younger
samples, many of his Méndez occurrences may represent
Late Maeestrichtian reworking of Campanian or Early
Maestrichtian faunas.
The type locality of G. conica White (TYPE 1 herein;
see Appendix) is situated in the Méndez shale about 2.2
kilometers from Tamuin (Guerrero) just east of the
bridge crossing of the ciudad Valles—Tampico highway
(Rt. 110) over the Rio Huiches and about 100 yards west
of kilometer post K101.00. G. conica occurs at this locality
and in a number of localities in the type area along the
Tampico—Cuidad Valles highway between kilometer posts
K96.00 and K101.00. At all of these localities, G. conica 1s
associated with a fauna containing A. mayaroensis (Boll) ,
G. duwi Nakkady, G. aegyptiaca Nakkady, G. contusa
(Cushman) , G. arca (Cushman) , G. stwarti (de Lapparent)
s.s., G. gansseri (Bolli), P. deformis (Kikoine), R. fructi-
cosa (Egger), R. rugosa (Plummer) and other species
diagnostic of the lower part of the A. mayaroensis subzone.
In northern Mexico north of Monterrey and Mamulique
Pass on the Mexico City—Nuevo Laredo highway (Rt. 85),
G. conica occurs abundantly at MX 174 (see Appendix) in
a fauna which appears to be diagnostic of the upper part of
the G. gansseri subzone.
In Texas G. conica White has been observed only in
the upper part of the Kemp clay in Falls County (TX
267A-C, 268—270, see Appendix) . Kemp samples from a 20
foot interval below the Kemp clay—Kindaid (Midway)
contact contain G. stwarti (de Lapparent) s.s., G. conica
White, G. gannseri Bolli, G. aegyptiaca Nakkady, G. duwi
Nakkady, G. trinidadensis Gandolfi, R. hexacamerata Bron-
nimann, R. reicheli Bronnimann, R. rugosa (Plummer) , P.
excolata (Cushman) , P. palpebra Bronnimann and Brown,
R. fructicosa (Egger), P. deformis (Kikoine), and other
species that characterize the upper part of the G. gansseri
subzone. It is noteworthy that A. mayaroensis is completely
absent from this fauna.
The writer has also observed G. conica in samples
given to him by H. Bolli from the Upper Maestrichtian por-
tion (A. mayaroensis subzone) of the Guayaguayare forma-
tion of Trinidad. Gandolfi (1955, pp. 65, 66, pl. 5, figs. 8a-
c) recorded this species from the Colon shale of Colombia
in the upper part of his Pullenia cretacea zone and in his
Siphogenerinoides bramlettei zone.
G. conica has been figured from the Maestrichtian ot
Egypt (see synonymy) and from the Maestrichtian of ‘Vur-
key.
Globotruncana contusa (Cushman)
Plate 75, figures 18-20; Plate 77, figures 1-9; Plate 78, figures
6-11; Plate 92, figures 10-12; Plate 96, figures 11, 13-16
1918. Rosalina linnei d’Orbigny “mutation caliciforme’’, de Lapparent,
Mém. Carte. Géol. France, p. 8, tf. 2: fig. | (=a nomen nudum) .
1926. Pulvinulina arca Cushman var. contusa Cushman, Contr. Cush-
man Lab. Foram. Res., vol. 2, pt. 1, p. 23.
1928. Globotruncana conica var. plicata White, Jour. Paleont., vol. 2,
No. 4, pp. 285, 286, pl. 38, figs. 7a-c.
1941. Globotruncana linnei d’Orbigny caliciformis Vogler, Palaeonto-
graphica, Suppl. Bd. 4, Abt. 4, p. 288, pl. 24, fig. 23.
1946. Globotruncana arca (Cushman) var. contusa (Cushman) , Cush-
man, U.S. Geol. Sur., Prof. Paper, No. 206, p. 150, pl. 62, figs.
ba-c,
1948. Globotruncana contusa (Cushman), Cita, Riv. Ital. Pal., vol.
54, No. 4, pp. 150, 151, pl. 3, figs. 6a-c.
1951. Globotruncana contusa (Cushman), Bolli, Jour. Paleont., vol.
25, No> 2, p» 196; pli 34) figs:) 7-9:
19538. Globotruncana contusa (Cushman), Subbotina, Trudy, Vses.
Neft., Nauckno—Issled. Geol. Razved. Instit., mn. ser., vol. 76, p.
192, pl. 11, figs. 3a-c; pl. 12, figs. la-c; 2a-c.
1953. Globotruncana conica White, Subbotina, Trudy, Vses. Neft.,
Nauckno—Issled. Geol. Razved. Instit., n. ser., No. 76, p. 192, pl.
11, figs. la-c; 2a-c.
1955. Globotruncana contusa (Cushman), Troelsen, Micropaleont.,
vol. 1, No. 1, pp. 76-81, text-figure 2: figs. a-g.
1955. Globotruncana contusa contusa (Cushman), Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, p. 54, pl. 4, figs. 2a-c.
1955. Globotruncana contusa patelliformis Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 54, pl. 4, figs. 2a-c.
1956. Marginotruncana contusa (Cushman), Hofker, Natuurh. Ma-
andbl., vol. 45, Nos. 5-6, p. 53, text-fig. 9.
1957. Globotruncana (Globotruncana) contusa (Cushman), Edgell,
Micropaleont., vol. 3, No. 2, pp. 111, 112, pl. 2, figs. 10-12; pl. 3,
figs. 7-9; pl. 4, figs. 1-3.
1957. Globotruncana contusa (Cushman). Sacal and Debourle, Soc.
Géol. France, (n. sér.), Mém. No. 78, p. 59, pl. 28, figs. 11-13.
1957. Globotruncana plicata White, Sacal and Debourle (part), Soc.
Géol. France, n. sér., Mem, No. 78, p. 59, pl. 28, figs. 11-13.
1959. Globotruncana contusa (Cushman), Olvera, Univ. Nacional
Aut, Mexico, Fac. Cien., Dept. Biol., Tesis Prof., pp. 43, 44, pl.
5, figs. 6-8.
1960. Globotruncana contusa (Cushman), Olsson, Jour. Paleont., vol.
34, No. 1, p. 50, pl. 10, figs. 25, 26.
1961. Globotruncana contusa cf. patelliformis Gandolfi, Corminboeuf,
Eclogae Geol. Helv., vol. 54, No. 1, p. 112, pl. 1, figs. la-c.
1962. Globotruncana contusa galeoidis Herm, Bayer, Akad. Wiss.,
Math.—Nat. KI., Abh., n. ser., No. 104, pp. 74-75, pl. 1, figs. 3-4;
pl. 9, figs. 6-14.
1962. Globotruncana contusa contusa (Cushman) , Herm, Bayer. Akad,
Wiss. Math.—Nat. Kl., Abh., n. ser., No. 104, p. 72, pl. 1, figs.
4a-c; pl. 9, figs. 1-5.
1962. Globotruncana (Globotruncana) contusa (Cushman), Berggren,
Stockholm Contr. Geol., vol. 9, No. 1, pp. 51-54, pl. 9, figs. 3a-4b.
1963. Globotruncana contusa (Cushman), Bronnimann and Rigassi,
| Eclogae Geol. Helv., vol. 56, No. 1, pl. 16, figs. 2a-c.
1963. Globotruncana (Globotruncana) plicata caliciformis Vogler, Van
Hinte, Jahrb. Geol. Bund., Sond. 8, p. 64, pl. 3, figs. 2a-c.
1964. Globotruncana contusa (Cushman), Olsson, Micropaleont., vol.
10, No. 2, pp. 163, 164, pl. 2, figs. 5a-c; pl. 3, figs. 6a-c; 9a-c.
Description.—Test deeply umbilicate,
quite spiroconvex (mean T’X/TX value —0.071) with
five to seven chambers in the last whorl. Double keel
present in early whorls; in last whorl strongly inturned
-umbilically; often merging to form a single keel. Cham-
bers spirally elongate, crescent-shaped, typically highly
crenulate, separated by curved, raised, often highly beaded
sutures. Chambers umbilically elliptical to subrectangular,
trochospiral,
separated by slightly raised, beaded sutures. Primary aper-
ture interiomarginal, umbilical in position. Umbilicus cov-
ered by spiral system of tegilla showing intralaminal and
infralaminal accessory apertures. Stout spines sometimes
present on the spiral surface of test. Chambers umbilically
somewhat more rugose. Outer wall radial hyaline, perforate
except for spines, rugosities, and keels. Spines and rugosities
ultragranular hyaline, imperforate. Keels when double both
radial hyaline, imperforate and ultragranular hyaline, im-
perforate (variety of type 2; Text-figure 40). Tegilla and
septal walls microgranular hyaline, finely perforate.
Remarks.—G. contusa (Cushman) is closely related to
G. fornicata Plummer. Transitional forms between G. con-
tusa and G. fornicata are common in Early Maestrichtian
strata (R. swbeircumnodifer subzone) and can only be dis-
tinguished as such by careful measurement of sectioned
specimens. As suggested by Bolli (1951, table 1), by Berg-
gren (1962, p. 53), and in Text-figure 35 herein, G. contusa
arose from G. fornicata. Berggren (ibid.) stated “The
transition from G. fornicata to G. contusa is accomplished
by the development of the following features: increase in
convexity of the spiral side, increase in size and number
of chambers, increased development of undulating surface
in adult stage, decrease in size of double keel, and greater
development of the umbilical cover plate.” A suppressed
G. fornicata stage of development is clearly visible in most
sectioned specimens of G. contusa S.s.
Form analysis data for G. contusa is presented in Text-
figure 38. Standard deviations and means of form analy-
sis measurements are shown in Table 2. TVext-figure 39 is
a scatter plot of T’X/TX and D-D’ values of G. fornicata
and G. contusa. G. contusa can best be separated on the
basis of its T7X/TX values. G. contusa has a mean T’X/TX
value of 0.071 whereas G. fornicata has a mean T’X/TX
value of 0.422 (Table 2). Measurements of thin-sectioned
topotypes of G. fornicata, as well as an examination of
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 331
=
z ”
wo} Suleul eu & Text — Figure 35: Suggested Phylogenetic Relationship of Double
e/aoes eg au s
=| esac 45] 8 Keeled Species of Globotruncana s.s
“A a> 9] <I 2
=| 5
Gl) le
° e|/os
e o/|3°o
3| O|2>
a =
v
Ec
5
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vl og
oleae vo
Yel < 3) a i]
=5 E 2 = al
c S= 5 rd ES es
=| s|23) < Z ¢ g]s
|) Biles ° = S
7) = os = — a
=i sil cam|leoat = Go be a i
a > c | =
g| 2 5 E be Rea Ras
=|) LL ea <$5 + sa
iG ee
=§ |= a 8
oetiol § 3 1
Lire) <= =
1 je 2 5
2 a4 2 = e
3 4 =
0 = = °
a ees = = = iS
E Oo o) oy a= a
be 2 Jin ¢| Z| = 3
2 = e]=
= hy Fy 2 °
3 cals Sites “rele E Jol? g
oi le 55)C# @| & 0A a €}e= o
S| 2] s/es| © Fy 3 of = 5° =
2/6] =|2% 1 C) a =. =
BS SSR > =], ss e [eds
1S) —— = = ra) = let =
= Sl 2B Ws i ~ a} of OF e ae =
& a5 = 2 zg a oK-— = ro)
a 52 3 2 wy 2 Oo r+ —
> 23 ¥ 5 ar =
~ E Fi ee als Pamiats
aie el) & “1 °l->- >
a —
=| 3 6 +
2 rc)
iF 3 ar
vo s
= ae
€ |Oe <=
c Su ° 2
S ees <
c =r
s =3|_4
t= 2S °
4] §}ea] 5
2 B
z/° |28
= g
7 ¢
3 5
< u it <4-
| — Sea
c
S a
7 e
2 ¢
5
[e) =
Plummer’s types, seem to indicate that Plummer’s types are
atypical rather than typical of G. fornicata. Three sectioned
topotypes show a mean T’X/TX value of 0.232. For this
reason the lower T’X/TX limit of G. fornicata is perhaps
rather rigid. T’X/TX=0.15 is arbitrarily chosen herein as
the upper limit of G. contusa whereas T’X/TX—0.20 is
arbitrarily taken as the lower limit of G. fornicata. Speci-
mens having T’X/TX values greater than 0.15 and less
than 0.20 are considered transitional.
As noted by Troelsen (1955, pp. 80, 81) and Berggren
(1962, p. 253), there are two “varieties” of G. contusa. The
typical form (referred to herein as G. contusa s.s.) is high-
spired and shows deep plications on the spiral surface of
its chambers whereas another “variety” (referred to herein
as G. contusa s.l.) is smaller, somewhat lower-spired, often
spinose spirally, and lacks plications spirally. Troelsen and
Berggren believed that these two forms intergrade. The
writer finds that G. contusa s.s. is abundant in the dA.
mayaroensis subzone whereas G. contusa s.l. is more abun-
dant in the G. gansseri subzone.
An examination of the holotype of G. contusa patelli-
332 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 36
A
22,
Globotruncana
Tilev 1951
fig.
- 5601 0.476 J0.532]0.646)0.406 JO. 392 J0.715]0.680
aes
Pera 220 z
:
All measurements in millimeters.
* Hypotype of G. falsostuarti (Sigal) from Sigal.
formis Gandolfi (No. 20849 PRI) indicates that it corres-
ponds rather closely with the nonplicate “‘variety” (G.
contusa s.l.) mentioned above although it does show weak
plications on its last two chambers. At present, the writer
prefers to include the nonplicate form under G. contusa.
However, it should be pointed out that G. contusa s.l. (=
G. contusa patelliformis Gandolfi) may be homeomorphic
after G. contusa s.s. and only distantly related to this latter
form. It is conceivable that G. contusa s.l.
G. plummerae Gandolfi ancestor. This
needs more careful study.
arose from a
varietal form still
G. contusa (Cushman) seems to have been first fig-
ured in the literature by De Lapparent (1918, tf. 2, fig. j)
who referred to it as Rosalina linnei d’Orbigny ‘‘mutation
caliciforme”’
trated by De Lapparent is unquestionably assignable to G.
contusa s.s. As noted by Ellis and Messina (Catalogue of
de Lapparent. The sectioned specimen illus-
Foraminifera, under G. linnei caliciformis Vogler) , De Lap-
parent’s use of the name “mutation caliciforme’’ is invalid
because it is not Latinized and does not conform to the
rules of zoological nomenclature. Thus, herein it is regarded
Vogler (1941, p. 288) Latinized De
Lapparent’s name “‘caliciforme” changing it to caliciformis.
as a nomen nudum.
The writer agrees with Ellis and Messina (bid.) that this
represents the first valid use of the name caliciformis and
that authorship of G. caliciformis should be attributed to
Vogler (1941) and not to De Lapparent (1918). The sec-
tioned form figured by Vogler (1941, p. 288, pl. 24, figs.
23), however, likewise seems assignable to G. contusa
(Cushman) s.s. although the illustration is poor.
G. conica plicata White (1928) and G. contusa gale-
oidis Herm (1962) are likewise regarded as junior syno-
nyms of G. contusa S.s.
The writer has examined the holotype and numerous
paratypes of G. contusa on deposit in the Cushman Collec-
tion (U.S. National Museum, Washington, D.C.) . Topo-
typic material has been collected from the Méndez shale at
Coco Station (National Railroad between Tampico and C,
Valles) .
Range.—G. contusa—stuartiformis assemblage zone; G.
gansseri: subzone to A, mayaroensis subzone. A few speci-
mens of G. contusa s.s. have been observed at locality
PR 789.00 (see Pessagno, 1960) in the Rio Yauco formation
of Puerto Rico. The fauna included at this locality is re-
ferrable to the upper part of the R. subcircumnodifer sub-
zone (R. subpennyt It contains predominantly
older elements such as G. G. linneiana, and G.
bulloides, but occasional specimens of G. gansseri Bolli and
G. contusa (Cushman) occur. There is no evidence of re-
working in this portion of the Rio Yauco formation.
zonule) .
fornicata,
Occurrence.—G. contusa s.s. occurs abundantly in the
Méndez shale of Mexico particularly in the area west of
Tampico. Its stratigraphic range has always been proble-
matical in this area. As indicated by Gandolfi (1955, plate
9), G. contusa has been reported to range down into Mén-
dez strata of Late Campanian age whereas in Trinidad,
‘Texas, and indeed elsewhere in the North America, Eurasia,
Africa, and Australia, G. contusa is usually restricted to
strata of Middle and Late Maestrichtian age (G. gansseri
subzone—A. mayaroensis subzone) .
An intensive study of the Méndez shale in the Tampico
area reveals that Méndez strata assignable to the A.
aroensis subzone (Late Maestrichtian) rest disconformably
on Méndez strata assignable to the G. elevata subzone (Late
Campanian) and the R. swbcircumnodifer subzone (Early
Maestrichtian) (Text-figure 2). These older Méndez strata
were reworked to varying degrees during Late Maestrichtian
times. Hence, it is not uncommon to find Late Maestrich-
tian species such as G. contusa, G. stuarti (de Lapparent)
s.s. and A. mayaroensis (Bolli) intermixed with typical
Campanian and Early Maestrichtian elements such as G.
calcarata Cushman, G. ventricosa White, G. fornicata Plum-
may-
mer, and G, linneiana (d’Orbigny) .
Cushman (1926, p. 25) mentioned two type localities
for G. contusa (Cushman): (1) Hacienda El Limon and
j
j
}
)
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 333
(2) Coco Station on the National Railroad between Tam-
pico and Ciudad Valles. As noted under G. arca (Cush-
man), this first locality is too vague to be useful and in
fact includes much of the countryside east of Tamuin
(=Guerrero). Thus, Coco Station by default becomes the
type locality of G. contusa. Méndez samples collected from
Coco Station (kilometer post K 574.00 on railroad) con-
tained sparse G. contusa together with a fauna which is
either assignable to the upper part of the G. gansseri sub-
zone or to the lower part of the A. mayaroensis subzone
(See TYPE 2, Appendix).
G. contusa has been observed in this study in the Cor-
sicana marl in Travis (TX 169-184) and Navarro (TX
281-287) Counties, Texas, and the Kemp clay (TX 186) of
Travis County, Texas. G. contusa has been figured by
Olsson (1960, 1964) from the Navesink formation of
New Jersey and from the overlying Red Bank formation.
Elsewhere in the Western Hemisphere G. contiusa has
been recorded by Bronnimann and Rigassi (1964) from
the Upper Maestrichtian Penalver formation of Cuba. It
also has been figured by Bolli (1951) from the Upper
Maestrichtian portion of the Guayaguayare formation of
Trinidad. Bolli (1957, figure 10) indicated that it is re-
stricted to the G. ganssert and A. mayaroensis subzones of
Trinidad. Gandolfi (1955) recorded and figured G. contusa
from the Colon formation of Columbia. As already noted,
the writer has found occasional specimens of G. contusa s.s.
in samples occurring in the Early Maestrichtian portion of
the Rio Yauco formation of Puerto Rico.
G. contusa occurs at essentially the same horizons in
Denmark, France, Austria, Switzerland, Russia, Tunisia,
and Australia (cf. Troelsen, 1955; Berggren, 1962; Sacal
and Debourle, 1957; Sigal, 1959; Herm, 1962; Corminboeuf,
1962; Subbotina, 1953; Dalbiez, 1955; and Edgell, 1957; see
synonomy herein). Vogler figured it under the name ol
G. linnei calciciformis from the Maestrichtian of Indonesia.
G. contusa would appear from its occurrences to be
Boreal, Tethyan, and Austral in terms of its distribution.
Globotruncana duwi Nakkady
Plate 83, figures 2-7; Plate 95, figures 12-14
1950. Globotruncana aegyptiaca Nakkady var. duwt Nakkady, Jour.
Paleont., vol. 24, No. 6, p. 690, pl. 90, figs. 17-19.
1956. Rugotruncana skewesae Bronnimann and Brown, Eclogae Geol.
Hely., vol. 48, No. 2, p. 550, pl. 23, figs. 4-6.
1961. Globotruncana tricarinata columbiana? Gandolfi, Corminboeuf,
Eclogae Geol. Helv., vol. 54, No. 1, p. 116, pl. 2, figs. la-c.
Description—Test trochospiral, deeply umbilicate,
planoconvex, peripherally truncated by narrew double
1) = Rosolina stuarti de Lapporent, 1918, pl. 1, fig. 7
TEXT-FIGURE 37 (2) = Rosalina stuarti de Lapparent, 1918, fig.
(3) = Rosalina stuarti de Lopparent, 1918, fig. b
(4) = Globotruncana stuorti (de Lapparent) of Bolli,
1945, pl. 9, fig. 18
5) = Specimens of Globotruncana falsostuarti Sigal
@ = Transitional from Sigal
© = Globotruncane conica White (6) = Specimen of Globotruncona esnehensis Nakkady
@ = Globotruncona stuarti (de Lapparent) from E|-Naggor
0.800 = 7
al
Q=6
0.700 e
°
O x ‘
° 8 g
< 0.600 F = z a
= © a a
z o) 2 =| L) es
= ° 3 —S
e : o ° 4
2 0.500F a a e 6
Oe a OF] 4
® °
4-4
. ° oa
0.400 %° e 3
°
0.300 = — es 1 n 1 =
21 0.2 03 1.4 05 06 07 0.8 09 10
T X/TX
keel; four or five chambers in last whorl. Chambers initially
Archacoglobigerina-like with or without weak double keel;
later chambers flattened spirally. Chambers arranged in two
whorls which expand rapidly in size (six measured speci-
mens show a mean D,-D’,/D,-D’, value of 3.63; cf. Text-
figure 41). Sutures heavily beaded, raised, curved spirally
and umbilically. Spiral surface of test somewhat rugose;
umbilical surface of test rugose; rugosities not arranged
in meridorial pattern. Spiral rim of narrow double keel
often possessing a few stout spines on the early chambers
of the last whorl. Primary aperture interiomarginal, um-
bilical in position. Umbilicus covered by spiral system of
tegilla showing intralaminal and infralaminal accessory
apertures. Outer wall radial hyaline perforate except for
rugosities, beads, and spines which are ultragranular hya-
line, imperforate and double keel which is both radial hya-
line, imperforate and ultragranular hyaline, imperforate
(‘variety” of type 2, Text-figure 40). Septal walls and
tegilla microgranular hyaline, perforate.
Remarks.—G. duwi Nakkady seems closely related to
G. aegyptiaca Nakkady. G. duwi differs from G. aegyptiaca
(1) by lacking a single-keeled early stage of development;
(2) by showing a much more rapid increase in chamber size
(last whorl about 3.6X as large as next to last whorl; cf.
Text-figures 27 and 41); (3) by having higher T’X/TX
values; (4) by being more rugose umbilically; and (5)
by often showing well-developed, stout peripheral spines
along the spiral rim of its double keel.
Preliminary form analysis measurements for G. duwi
are presented in Text-figure 41. Text-figure 28 is a scatter
plot of T’X/TX and D,-D,’/D,-D,’ values for G. duwi and
G. aegyptiaca.
334 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 38
PE 637
MX 79
PE 641-A
MX 5
PE 749
MX 78
S
2 PE 7/50
re (pbs 78
PEnee22.
PR 789.00
Globotruncana
(Cushman)
PE 636
MX 79
Trinidad
o
i
oO
OV
S|)
io)
e
Ww
0.770 0.65
(oe)
n
joo!
Oo
0.504]0.
0.358
o
°
=
>
o
°
to
co
o
Oo
ie)
—
‘S)
°
a
>
o
=
(jo)
~N
o
o
lo)
7}0.
ol voll aa
BAEC
56.0 552.0 a0 05 S8eOc68e olsenele
0.168]0.309]0. 238] 0.266] 0. aan 196
0.238]0.504]0.406 pete 393
.069
=
AP
°
°
a
ee
°
°
ND NR oO
wn Lee)
i>)
fo) io) +
° ° is)
Ww
Gy
°
°
Ww
a
°
°
>
Al
=
°
8.0°
o
(oo)
oO
°
o
°
~N
N
ih
o
°
o
oO
i=
Ss)
oO
=
©)
=
BR
NI
0.044
double
double
ae at: Di
Double kee
early stag
All measurements in millimeters.
°
°
~S
(=)
[o)
oO
wu
fon)
Ou
i
BEE
ET
e
E
* + = presence of double keeled early stage.
“x = G. icontusa sj-1. (= G. contusa patelliformis Gandolfitype)
Rugotruncana skewesae Bronnimann and Brown ap- under G. aegyptiaca). It is possible that G. duwi repre-
pears to be a junior synonym of Globotruncana duwi Nak- sents the megalospheric form and G. aegyptiaca represents
kady. Furthermore, as G. duwi lacks rugosities arranged in the microspheric form of a single species. It is known with
a meridorial pattern it cannot be included in Rugotrun- the larger Foraminifera that microspheric individuals faith-
cana Bronnimann and Brown (emended herein) . fully recapitulate their phylogenetic history during their
The phylogenetic relationship of G. aegyptiaca and G., ontogeny whereas the megalospheric forms usually omit
duwi is not clearly understood at this time (see remarks certain earlier growth stages. If one assumes that G. duwi
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 335
TEXT-FIGURE 39
@ Globotruncana fornicate Plummer
© Globotruncana contusa (Cushman)
A Tronsitional Forms: w= Topotype
r
0.800
© e
e
0.700
0.400
0.300 n 4 7 1
15
T X/TX
represents the megalospheric individual, he likewise can ex-
pect that growth stages such as the single-keeled growth
stage present in G. aegyptiaca would be lacking.
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert subzone to A. mayaroensis subzone.
Occurrence.—In the present study G. duwi has been
observed in the Upper Maestrichtian (A. mayaroensis sub-
zone) portion of the Méndez shale at numerous localities in
the ‘Tampico area and in the Middle Maestrichtian (G.
TEXT-FIGURE 40: Bosic types of keel structure omong double-keeled species of Globotruncana s.s
KEY
Type 1 = Globotruncang orca (Cushman) (Posterior)
Type 2 = Globotruncano bulloides Vogler (Po- terior)
= Radial hyaline imperforate
= Ultragranular hyaline imperforate
= Radial hyaline perforate
SR = Spiral rim
UR = Umbilical rim
IRA = Interrim Area
TEXT-FIGURE 41
Globotruncana
duwi
Nakkady
TX 267-C
TX 267-C
D.401 }0. 364 )0.364]0.378
Nh
S|
@) oS
[o) he
nn \O
oO’ oO’
ae
8 DD, |Wo.322 | 0.377
aaa
are Rr 0.196 . 238 0.196]0.205)
N
056
0.112 0.154) 0.112
9.0°]56.0°|54.0°
: .0° oe
anate xou 50.0" [o5.0° 0° 158.0°152.0°|46.0°
ante xoT _|20-0" 5.0" 18.0° |17.
XD 0.154 JO.168 j0.196/0.168,0.
[e)
i
nn
ms
eS
—
>
fo)
Dae
-
a
a
o
~<
o
Cc
co (o)
(oe) .
. Me
co) £
° (S)
[on
io
fo)
°
ui
nn
>
a
o
x
0
=|
ho
pan
(=)
°
a
wo
jo)
°
uw =
NO Sa)
is) [o)
° °
N
BR
5504 || 250
jo)
°
et
rar
fon
eo)
ro)
=
[o)
to
io)
i=)
(oe)
>
£
F 3 : 2 4.50
0.070]0.070 |0.084]0.084] 0.056] 0.056
0.070]0.084 ]0.084]0.084] 0.056] 0.056
eel at D
All measurements in millimeters
* iD 1D) = diameter of last whorl
aK Dp-D', = diameter of next to last whorl
gannseri subzone; upper part) portion of the Papagallos
shale at MX174 (see Appendix) near the Upper Cretaceous
—Tertiary contact along the Mexico, D. F—Nuevo Laredo
Highway (Rt. 85) north of Monterrey.
In Texas G. duwi occurs in the Corsicana marl in
Travis County and in Navarro County. It also occurs in
the Kemp clay in Travis County and in Falls County along
the Brazos River near the Milam County Line. In south-
western Arkansas G. duwi has been observed from the
Arkadelphia marl.
The writer has also observed G. dwwi in samples from
the Guayaguayare formation of Trinidad in association
with G. aegyptiaca s.s., G. contusa, A. mayaroensis, and
other species characteristic of the Late Maestrichtian. G.
duwi occurs in the Late Maestrichtian of Switzerland (A.
mayaroensis subzone; cf. Corminboeuf, 1961) and in the
Maestrichtian of Egypt.
Globotruncana elevata (Brotzen)
Plate 78, figures 12-14; Plate 80, figures 1, 2; 3-6 (transitional to
G. stuartiformis Dalbiez); Plate 81, figures 9-14; Plate 93, figures
1-5, 8; Text-figure 44
1931. Globotruncana arca (Cushman), Plummer, Univ. Texas Bull.
3101, p. 195, pl. 13, figs. 9a-c; not figs. 7, 8, 11.
1934. Rotalia elevata Brotzen, Deutsch. Ver. Palastinas Zeitschr., Leip-
zig, Deutschland, vol. 57, p. 66, pl. 3, fig. C.
1936. Globotruncana stuarti (de Lapparent), Renz (part.), Eclogae
Geol. Helv., vol. 29, No. 1, pl. 6, figs. 37, 38; (not 39, 40,
41); pl. 8, fig. 6.
1941. Globotruncana stuarti (de Lapparent), Vogler, Palaeonto-
graphica Suppl. Bd. 4, Abt. 4, p. 289, pl. 23, figs. 40-41.
1945. Globotruncana stuarti (de Lapparent), Bolli (part), Eclogae
Geol. Helv., vol. 37, No. 2, p. 236, text-fig. 1: fig. 27, not 28; not
pl. 9, fig. 9.
1946. Globotruncana arca (Cushman) , Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 150, pl. 62, figs. 5a-c; not 4a-c.
1951. Globotruncana rosetta (Carsey), Bandy, Jour. Paleont., vol.
No. 4, p. 509, pl. 75, figs. da-c.
1951. Globotruncana stuarti (de Lapparent), Tilev, Lausanne Univ.,
Mus. Géol., Lab. Géol., Min., Geophys., Bull. No. 103, pp. 54-41,
text-figs. 7a-d; not 8a-9d; not pl. 1, figs. 3a-c.
1953. Globotruncana andori de Klasz, Geol. Bavarica, No. 17, pp. 225-
235, pl. 6, figs. la-c.
1953. Globotruncana sp. 1, de Klasz, Geol. Bavarica, No. 17, p. 235,
pl. 7, figs. la-c.
1953. Globotruncana rosetta (Carsey) , Subbotina (part), Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p.
197, pl. 13, figs. Ga-c; not 5a-c.
1953. Globotruncana stuarti (de Lapparent) , Subbotina (part), Trudy
Vses. Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76,
p. 201, pl. 15, figs. 3a-c; 5a-c; not 4a-c.
1958. Globotruncana rosetta (Carsey), Hamilton, Jour. Paleont., vol
27, No. 2, p. 233, pl. 29, figs. 26-28.
1955. Globotruncana (Globotruncana) elevata elevata (Brotzen), Dal-
biez, Micropaleont., vol. 1, No. 2, p. 169, text-figs. 9a-c.
1955. Globotruncana rosetta insignis Gandolfi, Bull. Amer. Paleont.,
vol. 36, No. 155, p. 67, pl. 6, figs. 2a-c.
1957. Globotruncana (Globotruncana) elevata elevata (Brotzen), Ed-
gell, Micropaleont., vol. 3, No. 2, p. 112, pl. 4, figs. 4-6.
1957. Globotruncana rosetta (Carsey), Sacal and Debourle (part),
Soc. Géol. France, n. sér., Mém. No. 78, p. 68, pl. 27, fig. 14, not
18; pl. 28, figs. 1-2.
25%
530 PALALONLOGRAPHICA AMERICANA (V, 37)
1957. Globoltruncana andori de Klasz, Bolli, U.S. Nat. Mus., Bull. No.
215, p. 59, pl. 14, figs. 6a-c.
1959. Globotruncana stuwarti (de Lapparent), Ayala, Univ. Nac. Aut.
México, Instit. Geol. Paleont. Mex., No. 4, pp. 25, 26, pl. 5, fig.
6; pl. 6, figs. 1-3.
1959. Globotruncana gansseri Bolli, Ayala, Univ. Nac. Aut. México,
Instit. Geol., Paleont. Mex., No. 4, pp. 27, 28, pl. 7, fig. 4.
1960. Globotruncana (Globotruncana) stuarti elevata (Brotzen) , Pes-
sagno, Micropaleont., vol. 6, No. 1, p. 101, pl. 5, figs. 1-8.
1960. Globotruncana (Globotruncana) subspinosa Pessagno, Micro-
paleont., vol. 6, No. 1, pp. 101-102, pl. 1, figs. 1-9; pl. 5, fig. 5.
1962. Globotruncana (Globotruncana) stuarti elevata (Brotzen),
Pessagno, Micropaleont., vol. 8, No. 3, p. 362, pl. 1, fig. 10; pl.
25 figss LOenIe
1962. ? Globotruncana stuarti (de Lapparent), Herm, Bayer. Akad.
ear Math.-Nat. Kl., Abh., n. ser., No. 104, pp. 89-91, pl. 8,
ig. 1.
1962. Globotruncana andori de Klasz, Herm, Bayer. Akad. Wiss.,
Math.—Nat. K1., Abh., n. ser., No. 104, pp. 64-65, pl. 1, fig. 5.
1962. Globotruncana rosetta (Carsey), Barr, Paleontology, vol. 4, pt. 4,
pp. 575, 576, pl. 70, figs. 4a-c.
1964. Globotruncana stuarti stuartiformis Dalbiez, Olsson, Micro-
paleont., vol. 10, No. 2, p. 170, pl. 5, figs. 6a-c; 8a-c.
(964. Globotruncana stuarti elevata (Brotzen) , Olsson, Micropaleont.,
vol. 10, No. 2, p. 169, pl. 5, figs. 7a-c.
Description.—Test trochospiral, deeply umbilicate,
somewhat lobulate with spiral side planiform to slightly
convex and umbilical side strongly convex (mean T’X/TX
value=2.31 for 35 specimens). Periphery acutely angled
with prominent single keel; test single-keeled throughout
all, but early stages of ontogeny where keel is lacking alto-
gether. Five to nine chambers in the final whorl; chambers
in final whorl typically petaloid spirally but occasionally
triangularly shaped in the early portion of last whorl of
ephebic individuals; smaller neanic individuals often
possessing triangularly shaped chambers throughout last
whorl (cf. Text-figure 44, figs. 1-16). Sutures spirally ele-
vated, heavily beaded, curved. Umbilicus surrounded by
heavily beaded umbilical shoulder; covered by a spiral
system tegilla with intralaminal and infralaminal accessory
apertures. Primary aperture interiomarginal, umbilical in
position. Test usually smooth and nonrugose spirally ex-
cept for beaded sutures; smooth to slightly rugose umbili-
cally. Outer wall primarily radial hyaline perforate (often
coarsely perforate) except for beads and rugosites which
are ultragranular hyaline, imperforate and keels which are
radial hyaline, imperforate. Septal walls and tegilla micro-
granular hyaline, perforate.
Remarks.—G, elevata (Brotzen) is closely related to G.
stuartiformis Dalbiez and is in fact gradational with the
latter species. G. elevata differs from G. stwartiformis: (1)
by having a planiform to a nearly planiform spiral side and
a strongly convex umbilical side (mean T’X/TX value for
35 specimens of G. elevata=2.31; mean T’X/TX value for
26 specimens of G. stuwartiformis—0.92; cf. Table 2); (2) by
(mMorIOW)
sTSuouroyussl3
. . . . foe) wy a al . . . .
jo) io) jo) io) [o) io) jo) io)
Ko) fon ia) N [=) oO (=) Oo + \o [on
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e . . . a) ey
wn
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spb t
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en
(MotI0W)
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(2ueq *0)
potutuuedde
ee
eopapuusdde
exodr pesca
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0.29710.038]0.174
18.40
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9 fo.ona.s
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ane
GE
a [al
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HE
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:
\o ino —t N
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(uewysng)
esnjuoo
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(uewysng)
eau iuos|
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0.035
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BJEITUIOT wm
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(jusseddeqeap)
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2 © |) eer ea en ea es ie
Sy ea as Le La we} un iS = wy
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STWIOZTZIENAS || >< e 2
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Ht. double
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Ht. double
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standard Deviation
Tt: =
-
t
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of.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 337
usually having petaloid chambers spirally; and (3) by
usually being somewhat more coarsely perforate.
The writer regards the first difference cited above as
the most critical in the separation of these two species. Text-
figure 42 shows form analysis data for G. elevata and ‘Text-
figure 59 shows form analysis data for G. stuartiformis.
Text-figure 43 is a scatter plot of D-D’ and T’X/TX values
for G. elevata and G. stuartiformis. After having made form
analysis measurements of numerous sectioned specimens
and after having examined numerous free specimens and
figured specimens in the literature, the writer believes that
these species should be separated on the basis of their first
standard deviations (Table 2 and Text-figure 43). Hence,
T’X/TX=1.07 is taken as the upper limit of G. stuarti-
formis and T’X/TX=1.25 is taken as the lower limit of
G. elevata. Specimens having T’X/TX values greater than
1.07 and less than 1.25 are considered transitional herein.
As noted in the descriptions above, there is a great
amount of variation in the shape of the chambers of G.
elevata spirally. Brotzen’s type specimen shows petaloid
chambers throughout the last whorl. However, the writer
has found after examining numerous specimens of G. ele-
vata that triangularly shaped chambers are not uncommon
particularly in the last whorl of neanic individuals. (Text-
figure 44). Many ephebic or gerontic individuals show tri-
angularly shaped (G. stuartiformis-like) chambers in their
earlier whorls.
Globotruncana elevata (Brotzen) has been confused by
many workers with either Globotruncana arca (Cushman)
or G. rosetta (Carsey). For example, Plummer (1931, p.
195, pl. 13, figs. 9a-c; not figs. 7, 8, 11) included this form
under G. arca. Her specimen shows a planiform spiral
side, a highly convex umbilical side, and a well-developed
single keel. It seems to represent an immature form of G.
elevata. Cushman (1946, p. 150, pl. 62, figs. 5a-c; not figs.
4a-c) also figured G. elevata under the name of G. arca.
His specimen is again unquestionably assignable to G. ele-
vata. The differences between G. elevata and G. arca should
be apparent to most present-day workers. G. arca possesses
a double keel throughout its ontogeny and possesses a
spiroconvex test whereas G. elevata possesses a single keel
throughout its ontogeny and is planoconvex.
Bandy (1951), Subbotina (1953), Hamilton (1953),
Sacal and Debourle (1957), and Barr (1962) (see synon-
omy) have figured this species under the name of G.
rosetta (Carsey). As pointed out by Bronnimann and
Brown (1956, pp. 545, 546), Pessagno (1960, pp. 100, 101),
and Berggren (1962, p. 57-60) , G. rosetta possesses a narrow
double keel in its last whorl which often merges to form
a single keel. Rarely, it may possess a single keel on all
chambers of the last whorl. However, a double-keeled stage
is always visible in thin-section in its earlier whorls.
The holotype of G. andori de Klasz as figured by De
Klasz (1953) is not significantly different from that of G.
elevata (Brotzen). Both forms are single-keeled, planocon-
vex, and have well-developed petaloid chambers in the
final whorl. Hence, G. andori de Klasz is regarded herein
as a junior synonym of G. elevata (Brotzen) .
The writer has examined the holotype of G. rosetta
insignis Gandolfi (No. 20856) at the Paleontological Re-
search Institution, Ithaca, New York. This form is plano-
convex, single-keeled, and possesses petaloid chambers
spirally throughout its last whorl. It is regarded herein as
a junior synonym of G,. elevata Brotzen.
G. elevata Brotzen evolved from G. stuartiformis dur-
ing Late Campanian times (G. elevata subzone) by spiral
flattening and by obtaining a predominance of petaloid
chambers in its final whorl (Text-figure 34). The earlier
whorls of G. elevata both in thin-section and in free speci-
men usually show a suppressed G. stuartiformis stage of de-
velopment.
G. elevata in turn seems to have given rise to G. cal-
carata Cushman. The form described by Pessagno (1960) as
“G. subspinosa” may represent an intermediate stage of
development. G. swbhspinosa is regarded herein as a variant
of G. elevata and is not maintained as a separate species.
Range.—G. fornicata—stuartiformis assemblage zone, G.
elevata subzone. (P. elegans zonule) to G. contusa—stuarti-
formis assemblage zone (A. mayaroensis subzone) . G. ele-
vata seems to have reached its greatest abundance during
Late Campanian and Early Maestrichtian times. It is com-
mon but is not abundant in deposits of the Middle and
Late Maestrichtian of the Western Hemisphere.
Occurrence._In Mexico G. elevata is abundant in the
Late Campanian and Maestrichtian portion of the Méndez
shale in the Tampico area and equivalent deposits north-
ward to somewhat south of the Rio Grande (Text-figures
1, 2). In Texas, it occurs in the Late Campanian portion
(upper part) of the “Lower Taylor marl” in Travis County,
McLennan County, and Dallas County; in the Late Cam-
panian Wolfe City sand and Pecan Gap chalk of McLennan
County; and in the Late Campanian “Uppet Taylor marl”
of Travis and Limestone Counties. It has been observed in
the Early Maestrichtian portion of the Upson clay in Mav-
erick County and in the Neylandville marl of Limestone
County. It has been likewise observed in the Middle
Maestrichtian Corsicana marl of Travis and Navarro
338 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 43
g Transitional (1) = Globotruncona stuarti (de Lapporent) of Renz, 1936, pl. 8, fig. 6.
© Globotruncana stuartiformis Dolbiez (2) = Globotruncana stuarti (de Lapparent) of Tilev, 1951, fig. 74.
@ Globotruncana elevata (Brotzen) (3) = Globotruncana stuarti (de Lapporent) of Tilev, 1951, fig. 3d.
©+@ = Identical or near identical measurements (4) = Globotruncana stuarti (de Lapparent) of Tilev, 1951, fig. 8d.
0.900 —————— ; ——- ——
| ° °
ie)
é 2)
0.800 + a e
O 6 ° e e
° e
o.1
| ° , e
° ° ” “
~ 9.700 5 S| e 3
= g = elute e e
ig oo Tes © °
s =
= 5 e e e
a ° one 3 3 e
0,600 — 5 B e @ e.2
° a e
© o So ee
= = ‘i 5
e
e e
0.500 + )
°
e
g3
400 N lit oe) eS eee aT ==eL> jet ! 1 jeasey) i J
O50) 0:60NN01701 0180) 0:90) 10M TN upanezinnsnS3) Winl4y Gris (1:6) 179) nla Eriol zope airy yai2i 253) We27a zis iz Yo i zi zien 2903 !O os ns: ess a 4 gm
T’ X/TX
Counties and in the Kemp clay of Travis and Falls Coun-
tres?
In southwestern Arkansas G.
Early Maestrichtian Marlbrook marl and Saratoga chalk
and in the Middle Maestrichtian Arkadelphia marl.
elevata occurs in the
Elsewhere in North America G. elevata has been fig-
ured by Bandy (1951) under the name of G. rosetta from
the Campanian of San Diego County California and by
Olsson (1964) from the Mt. Laurel-Navesink and Mavr-
shalltown formations of New Jersey. The writer has also
seen this species in thin-section from the Late Campanian—
Early Maestrichtian strata of Panama.
In the West Indies G. elevata occurs in the Late Cam-
panian and Maestrichtian of Haiti and Puerto Rico. The
writer has also seen it in samples given to him by H. Bolli
from the Late Maestrichtian (Ad. mayaroensis subzone)
portion of the Guayaguayare formation of ‘Trinidad.
G. elevata is known from the Campanian and Maes-
trichtian of Austria, Bavaria, France, Italy, Russia, Israel,
Tunisia, Australia, Colombia, the East Indies, and the
Mid-Pacific guyot area.
Collignon (1959, table V) noted G. elevata through-
out the Campanian of Madagascar. He may be using this
name in the sense of Dalbiez (1955) who divided G. elevata
into the subspecies G. elevata elevata and G. elevata stuarti-
formis. It is likely that his reference to G.
Early Campanian Anapachydiscus wittekindi zone refers to
occurrences of G. elevata stuartiformis rather than to G.
elevata s.s. The writer has never seen G. elevata s.s. in the
elevata in his
Earliest Campanian deposits of the Western Hemisphere.
Globotruncana fornicata Plummer
Plate 63, figures 1-9; Plate 80, figures 7-9; Plate 96, figures 3, 4
1931. Globotruncana fornicata Plummer, Univ. Texas, Bull. 3101, pp.
198, 199, pl. 13, figs. 4a-c, 5, 6.
1932. Globotruncana fornicata Plummer, Sandidge, Jour. Paleont., vol.
6, No. 3, p. 285, pl. 44, figs. 12, 13.
1936. Not Globotruncana fornicata Plummer, Jennings, Bull. Amer.
Paleont., vol. 23, No. 78, p. 37, pl. 4, fig. 13.
1941. Globotruncana fornicata Plummer, Cushman and _ Hedberg,
Contr. Cushman Lab, Foram. Res., vol. 17, p. 99, pl. 23, figs.
18a-c.
1944. 2? Globotruncana fornicata Plummer, Cushman and Deaderick,
Jour. Paleont., vol. 18, p. 340, pl. 53, figs. 28a, b.
1945. Globotruncana leupoldi Bolli, Eclogae Geol. Hely., vol. 37, No. 2,
pp. 235, 236, pl. 9, fig. 17; text-fig. 1: figs. 25, 26.
1946. Globotruncana fornicata Plummer, Cushman, U.S. Geol. Sur.,
Prof. Paper, No. 206, p. 149, pl. 61, figs. 19a-c.
1948. Globotruncana fornicata Plummer, Cita. Riv. Ital. Pal., vol. 54,
No. 4, p. 153, pl. 3, figs. 8a-c.
1948. Globotruncana fornicata Plummer, Cushman, Maryland Dept.
Geol. Mines, Water Res., Bull. 2, p. 265, pl. 26, figs. la, b.
1952. Globotruncana fornicata Plummer, Sigal, 19th Cong. Géol. Inter-
nat., Monogr. Rég., ser. 1, Alger, No. 26, p. 35, text-fig. 39.
1953. 2 Globotruncana fornicata Plummer, Hamilton, Jour. Paleont.,
vol. 27, No. 2, p. 232, pl. 29; fig. 21.
1953. Globotruncana contusa (Cushman), Hamilton, Jour. Paleont.,
vol. 27, No. 2, p. 232, pl. 29, figs. 14-16.
1953. Globotruncana fornicata Plummer, Subbotina, Trudy, Vses.
Neft. Naucko—Issled. Geol. Razved. Instit., n. ser., No. 76, p. 184,
pl. 8, figs. 3a-c; 4a-c; 5a-c.
1955. Globotruncana fornicata fornicata Plummer, Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, p. 40, pl. 2, figs. 2a-c.
1955. Globotruncana contusa scutilla Gandolfi, Bull. Amer. Paleont.,
vol. 36, No. 155, p. 34, pl. 4, figs. la-c.
1955. Globotruncana fornicata manaurensis Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 41, pl. 2, figs. la-c.
1956. Globotruncana fornicata Plummer, Bronniman and Brown, Ec-
logae Geol. Helv., vol. 48, No. 2, pp. 542-544, pl. 21, figs. 7, 14,
15.
1957. Globotruncana (Globotruncana) fornicata Plummer, Edgell, Mi-
cropaleont., vol. 3, No. 2, p. 112, pl. 3, figs. 10-12.
TEXT-FIGURE 42
PL ‘343
3 Geeiecics | silts 2
3 shal as z f a A co}
IS6T AQTTL . a . i =| =, = .
9 “Sty So. * td
961 2uU0y
“4ST Xi
1249 Gd
V-T6¢ XL
sweee 899 Ad
O-T6¢ XL
969 dd
&
S m 4 a : ; 7 5 3s
o
00°68/ wa] S <
9EIl Ad] o 5
00°68Z Yd
Gel aa
00°68 ua
Yel dd
00°68Z Yd
€€l ad
a = ey f * . a
. wo N oO a
[o) [o) N as
o a Vo) ° va) ° ial
nn oO = = 5 . Ld
Ne} + Oo r
a
S rat 5 %9 ° ° ° iS) =
00° 68Z ie :
SzI 5
00° 682 ae
O2T
00°68Z Yd S ) 3
6IT ad] | al : : x 3 ® =
3sP09 FIN ‘un 3 o o] a] Al o
FITOG WOAT QTT ad : =| "aes ie eau ae ese eo
Q Q 2 ical S S onl
. ° ° nw N
ay co; ¢ ei lees
*% LL
~224
60
D . 238
Yd] o
ga} 9 ese leu ls |e lt sceillia sell cce
So Pe) et wy =I {=} i=} int
00°66Z Ha} & o}] of 6 al oo
wn . No}
* OTT
(uez302g)
BVPABTO
BuBounaqOqgoT5
All measurements in millimeters.
1&8).
Topotypes of G. subspinosa Pessagno,.
pl.-5, fige.
Pessagno (1960,
*
Off graph: Text - Figure
tee
Gur CRETACEOUS FORAMINIFERA: PESSAGNO 339
TEXT - FIGURE 44:
Variation in Chamber Shape on Spiral Side of Globotruncana elevata (Brotzen).
KEY
Figures 1 - 16 = 6. elevata [Brotzen).” Figure 17 - G. stuartiformis Dalbiez. Note triangular chambers of typical form.
“Figures 1 - 10 show typical forms with petaloid chambers in last whorl
“Figures 11 - 16 show petaloid chambers and variable number of triangular chambers in last whorl
“Figure 14 shows "6. subspinosa Pessagno’’ variety trom which 6. calcarata probably arose
Globotruncana plicata White, Sacal and Debourle (part) , Soc.
Géol. France, n. sér., Mem. No. 78, p. 61, pl. 28, fig. 9; not fig.
10.
Globotruncana fornicata Plummer, Sacal and Debourle (part),
Soc. Géol. France, (n. sér.) Mém 78, p. 61, pl. 28, figs. 6, 7, 14,
15; not fig. 8.
Globotruncana fornicata Plummer. Olvera, Univ. Nacional Aut.
México, Fac. Ciencias, Dept. Biol.. Tesis Prof., pp. 44-56, pl. 5,
figs. 9-11.
Globotruncana fornicata Plummer, Ayala, Univ. Nacional Aut.
de Méx., Instit., Geol. Pal. Mexicana, No. 4, pp. 21, 22, pl. 3,
figs. 6;.25; pl. 4, figs. I, 2, 73.
Globotruncana (Globotruncana) fornicata Plummer, Pessagno,
Micropaleont., vol. 6, No. 1, p. 101, pl. 4, fig. 7.
. Not Globotruncana fornicata Plummer, Klaus, Eclogae Geol.
Helv., vol. 52, No. 2, p. 825, pl. 8, figs. 4a-c.
Globotruncana fornicata Plummer, Graham and Clark, Contr.
Cushman Foram. Res., vol. 12, pt. 3, p. 112, pl. 5, figs. 10a-c.
Globotruncana (Globotruncana) fornicata Plummer, Pessagno,
Micropaleont., vol. 8, No. 3, p. 362, pl. 4, figs. 4, 5, 11.
Globotruncana fornicata Plummer, Barr, Paleontology, vol. 4,
pt. 4, pp. 570, 571, pl. 69, figs. 6a-c; pl. 72, figs. 1 72.
Globotruncana fornicata Plummer, Olsson, Micropaleont., vol.
10, No. 2, pp. 164, 165, pl. 2, figs. 3, 4; pl. 3, figs. 7a-c; 8a-c.
Description.—Test trochospiral, umbilicate, spirocon-
vex (mean T’X/TX value for 19 specimens = 0.422; Table
2; Text-figure 45) , double-keeled with keels usually reflect-
ed umbilically. Coiling predominantly right. Four to five
(rarely six) chambers in last whorl which spirally are
narrow, elongate, crescent-shaped, and typically highly
crenulate and which umbilically are noncrenulate and
subrectangular in shape. Sutures raised, beaded, highly
curved spirally; raised, beaded, slightly curved umbilically.
Chamber surfaces spirally and umbilically smooth to
slightly rugose. Double keels strongly developed, often high-
ly beaded; occasionally merge to form single keel in last
whorl of gerontic specimens; rare specimens single-keeled
throughout last whorl. Umbilicus deep, covered by spiral
system of tegilla with intralaminal and infralaminal acces-
sory apertures. Primary aperture, interiomarginal, umbili-
cal in position. Outer wall radial hyaline, perforate except
for double keels, beads, and rugosities. Double keel radial
hyaline imperforate and ultragranular hyaline, imperfo-
rate (‘“variety” of type 2; Text-figure 40). Beads and
rugosities ultragranular hyaline, imperforate. Tegilla and
septal walls microgranular hyaline, finely perforate.
Remarks.—G. fornicata Plummer is completely transi-
tional into G. contusa (Cushman). Transitional forms are
common in strata (Rio Yauco formation) assignable to the
R. subcircumnodifer subzone (R. subpennyi zonule) of
Puerto Rico. The writer has examined the holotype and
paratypes of G. fornicata Plummer at the Paleontological
Research Institution, Ithaca, New York. The holotype and
paratypes are somewhat more convex than typical for this
species. In addition, the holotype displays left-handed coil-
ing whereas the several paratypes display right-handed coil-
ing. Topotypes examined by the writer from the “Upper
Taylor marl” of Travis County, Texas, are predominantly
coiled to the right and are convex spirally. Whereas the
mean T’X/TX value of 19 sectioned specimens of G.
fornicata (Table 2; Text-figure 45) is 0.422, the mean
T’X/TX value of three sectioned topotypes is 0.252.
G. fornicata is separated from G. contusa largely on
the basis of its spiral convexity. The mean ‘T’X/TX value
of G. contusa is 0.071 (Table 2; Text-figure 38) and is con-
siderably less than that cited for G. fornicata above. Be-
cause the type material is atypically spiroconvex and shows
lower T’X/TX values than normal for this species, G.
fornicata cannot be readily separated from G. contusa using
statistical limits such as standard deviations. Text-figure
39 is a scatter plot of D-D’ and T’X/TX values for sectioned
free specimens of G. contusa and G. fornicata. T’X/TX =
0.15 is taken herein as the upper limit of G. contusa whereas
340 PALAEONTOGRAPHICA AMERICANA (V, 37)
TEXT-FIGURE 45
i]
i=]
oO
(3)
Sey S N N i=) So
v ~m isa) is) jo)
A] 3] 4 : y : 2 5 st
v ) fon) fon fon) tony ron
orale ee) ee) ice) ee) (ee) SUS
~ ~~ ~ ~ ~
o} H| 5 ey
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OH] Ay Au os Ay Ay AH
So i)
a =
KH tw
Np foo}
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oO Oo
oO n
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KK =
= Transitional
T’X/TX = 0.20 is taken herein as the lower limit of G. the basic species of double-keeled Globotruncana. It un-
fornicata, Sectioned specimens having T’X/TX_ values doubtedly gave rise to G. contusa and probably gave rise to
greater than 0.15 and less than 0.20 are considered transi- the G. arca (Cushman) branch as well as to G. plummerae
tional. Gandolfi and G. nothi (Bronnimann and Brown) .
In general, G. fornicata seems to become more convex The writer examined the holotypes of G. contusa scu-
spirally with respect to Late Cretaceous time (Santonian tilla Gandolfi (No. 20848) and G. fornicata manaurensis
to Early Maestrichtian). This trend could easily be es- Gandolfi (No. 20834) at the Paleontological Research In-
tablished by form analysis of sectioned free specimens from stitution, Ithaca, New York, and believes that both of these
this time interval although no attempt to substantiate it has forms should be included within G. fornicata Plummer.
been made herein. G. leupoldi Bolli, figured and described by Bolli
G. plummerae Gandolfi is somewhat similar to G. (1945) , appears to be a junior synonym of G. fornicata.
fornicata Plummer but possesses noncrenulate and inflated Range.—G. bulloides assemblage zone, M. concavata
chambers spirally that tend to be somewhat spinose in the subzone to G. fornicata-stuartiformis assemblage zone, R.
early portion of the last whorl. subcircumnodifer subzone (R. subpennyi zonule).
As indicated in Text-figure 35, G. fornicata is one of Occurrence.—In Mexico G. fornicata occurs abundantly
Gur CRETACEOUS FORAMINIFERA: PESSAGNO 541
in the Santonian and Early Campanian portions of the San
Felipe formation throughout the Tampico area and the
front ranges of the Sierra Madre Oriental. In northern
Mexico, it has been observed in the Santonian portion of
the San Felipe formation at Boca Canyon south of Monter-
rey and at Mamulique Pass along the Mexico D.F.—Nuevo
Laredo Highway (Rt. 85) north of Monterrey. It also oc-
curs abundantly throughout the Campanian and Early
Maestrichtian portions of the Méndez shale and Papagallos
shale in the area of study (Text-figures 1-2).
In Texas G. fornicata is common to abundant through-
out the Santonian portions of the Austin chalk in Kinney,
Travis, McLennan, and Dallas Counties and in the Early
Campanian (reworked) portion of ithe Austin chalk in
Dallas County. It likewise has been observed in the Cam-
panian Taylor formation in the “Lower Taylor marl” mem-
ber of Travis, McLennan, and Dallas Counties; in the
Wolfe City sand member of McLennan County; in the
Pecan Gap chalk member of McLennan County; and in the
“Upper Taylor marl” member of Travis and Limestone
Counties. It has been observed in the Early Maestrichtian
portion of the Upson clay of Maverick County and in the
Neylandville marl of Navarro County (Text-figures 1-2) .
In southwestern Arkansas G. fornicata occurs in the
Campanian Brownstown marl, Ozan formation, and An-
nona chalk and in the Early Maestrichtian Marlbrook marl
and Saratoga chalk (Text-figures 1-2) .
Cushman (1946, p. 149), in addition to the lithic units
cited above, noted G. fornicata in the Selma chalk of Ala-
bama and Mississippi. G. fornicata has been noted by
Graham and Clark (1961) from the Upper Cretaceous of
Merced County, California, and by Olsson (1964) from the
Mt. Laurel and Marshalltown formations of New Jersey and
the Mt. Laurel—Navesink formation of Delaware. G. forni-
cata is also known from the Upper Cretaceous of Maryland.
The writer has seen G. fornicata in rock thin-section from
the Late Campanian and Early Maestrichtian of Panama.
It also occurs in the Upper Cretaceous of Cuba, Puerto
Rico, Trinidad, Venezuela, and Colombia.
G. fornicata is common to the Upper Cretaceous of
Eurasia, North Africa, Australia, and the Mid-Pacific guyot
area.
Its geographic distribution definitely indicates that
its distribution during Santonian, Campanian, and Early
Maestrichtian times was Boreal, Tethyan, and Austral.
Globotruncana gansseri Bolli
Plate 75, figure 1; Plate 92, figures 13-18; Plate 95, figures 1-4
1951. Globotruncana gansseri Bolli, Jour. Paleont., vol. 25, No. 2, pp.
196, 197, pl. 35, figs. 1-3.
1951. Globotruncana lugeoni Viley, Lausanne Univ., Mus. Géol., Lab.
Géol. Min., Géophys., Bull., No. 103, pp. 41-46, text-figs. 10a-c;
lla-d; 12a-c; pl. 1, figs. 5a-d.
1951. Globotruncana lugeoni var. angulata ‘Tiley, Lausanne Univ.,
Mus. Géol., Min., Géophys., Bull., No. 103, pp. 47-50, text-figs.
13a-d; pl. 3, figs. la-d.
1953. Globotruncana gansseri Bolli, Hamilton, Jour. Paleont., vol. 27,
No. 2, p. 232, pl. 29, figs. 18-20.
1953. Globotruncana sp. 2, de Klasz, Geol. Bavarica, No. 17, pp. 235,
236, pl. 7, figs. 2a-c.
1955. Globotruncana gansseri gansseri Bolli, Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 69, pl. 6, figs. 5a-6c; 8a-c.
1955. Globotruncana rosetta pettersi Gandolfi, Bull. Amer. Paleont.,
vol. 36, No. 155, p. 68, pl. 6, figs. 3a-4c.
1955. Globotruncana wiedenmayeri magdalenaensis Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, p. 72, pl. 7, figs. 3a-c.
1955. Globotruncana wiedenmayeri wiedenmayeri Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, p. 72, pl. 7, figs. 4a-c.
1956. Rugotruncana gansseri (Bolli), Bronnimann and Brown, Eclogae
Geol. Helv., vol. 48, No. 2, p. 549, pl. 23, figs. 7-9, text-fig. 23.
1957. Globotruncana (Globotruncana) lugeoni Tiley, Edgell, Micro-
paleont., vol. 3, No. 2, p. 113, pl. 2, figs. 7-9.
1959. Not Globotruncana gansseri Bolli, Ayala, Univ. Nac. Aut.
México, Instit. Geol., Pal. Mex., No. 4, pp. 27, 28, pl. 7, fig. 4.
1960. Globotruncana monmouthensis Olsson, Jour. Paleont., vol. 34,
No. 1,. pp. 50, 51, pl. 10, figs. 22-24.
1960. Globotruncana (Rugotruncana) gansseri (Bolli) , Pessagno, Mi-
cropaleont., vol. 6, No. 1, p. 102, pl. 4, fig. 11.
1964. Globotruncana gansseri Bolli, Olsson, Micropaleont., vol. 10, No,
2, pp. 165, 166, pl. 3, figs. 2-5.
1964. Globotruncana gansseri dicarinata Pessagno, Olsson, Micro-
paleont., vol. 10, No. 2, p. 166, pl. 3, fig. 1.
Description.—Test low trochospiral,
(mean T’X/TX value for 11 specimens—5.12) , subcircular,
mildly lobulate with usually four or five chambers in final
whorl; two and a half to three whorls of chambers; early
whorls globigeriniform in thin-section with weakly devel-
oped double keel; final whorl sometimes single-keeled or
with double keel which merges to form a single keel. Spiral
side planiform, sometimes slightly concave; sutures raised,
beaded, curved spirally, separating crescent-shaped cham-
bers. Umbilical side, highly convex; sutures depressed, non-
beaded to weakly beaded, separating subrectangularly
shaped chambers. Chambers in peripheral view typically
hemispherical. Spiral side relatively unornamented except
for beaded sutures and occasional rugosities. Umbilical side
smooth to highly rugose; rugosites not aligned in a meri-
dorial pattern. Umbilicus, deep covered by spiral system of
tegilla showing infralaminal and intralaminal accessory
apertures. Primary aperture interiomarginal, umbilical in
planoconvex
position. Outer wall radial hyaline perforate except for
beads, rugosities, and keels. Rugosities and beads ultra-
granular hyaline, imperforate; keel radial hyaline imper-
forate when single; radial hyaline, imperforate and _ ultra-
granular hyaline imperforate (‘“variety” of type 2; Text-
figure 40) when double. Septal walls and tegilla micro-
granular hyaline, finely perforate.
Remarks—Bronnimann and Brown (1956, p. 549)
placed this species in Rugotruncana Bronnimann and
349 PALAKONTOGRAPHICA AMERICANA (V, 37)
Brown. This usage was followed by a number of other
workers including Pessagno (1960, p. 102). Inasmuch as
G. gansseri shows rugosities which are not aligned in a
meridorial pattern and possesses a Archaeoglobigerina ra-
ther than a rugoglobigerine early stage, it is excluded from
Rugotruncana s.s. (see emended definition of Rugotrun-
cana herein) .
The writer examined the holotype and paratypes of G.
gansseri at the U.S. National Museum, Washington, D.C.
The three paratypes are not referrable to G. gansseri 5.5.
One of the three specimens is referable to G. dwwi Nakkady
and the remaining two are assignable to Rugotruncana
subpennyi Gandolfi. The latter two forms possess double
keels in the last whorl and rugosities arranged in a meri-
dorial pattern.
G. lugeoni Tiley (1951), G. angulata
Tiley (1951), G. rosetta pettersi Gandolfi (1955), G.
denmayeri wiedenmayeri Gandolfi (1955), G. wiedenmay-
eri magdalenaensis Gandolfi (1955), and G. monmouthen-
sis Olsson (1960) are considered junior synonyms of G.
gansseri Bolli. The writer examined the holotypes of Gan-
dolfi’s species noted above in the collection of the Paleon-
tological Research Institution, Ithaca, New York, and has
found no significant reason to separate Gandolfi’s forms
from G. gansseri. The holotype of G. monmouthensis was
examined at the U.S. National Museum, Washington, D.C.,
and found to fall within the limits of G. gansseri Boll.
lugeon t var.
wie-
G. gansseri Bolli seems to have evolved directly from
an Archaeoglobigerina ancestor (cf. Text-figure 35) rather
than from a Rugoglobigerina ancestor as suggested by Pes-
sagno (1960, p. 102). Sectioned specimens display a well-
developed Archaeoglobigerina stage which is often com-
pletely nonrugose and may display a weakly developed
double keel.
Range.—G.,
R. subcircumnodifer subzone (R. subpennyi zonule; upper
part) to G. contusa—stuartiformis assemblage zone; G. gans-
fornicata—stuartiformis assemblage zone,
seri subzone to lower part of A. mayaroensis subzone. Occur-
rences in the uppermost part of the G. fornicata—stuarti-
formis assemblage zone were noted by Pessagno (1960)
Puerto Rico in the Rio Yauco formation where there is no
physical evidence of reworking. Olsson (1964, p. 158, text-
figure 2) noted this species at essentially the same horizon
in the Maestrichtian of New Jersey.
Occurrence.—In Mexico G. gansseri has been observed
in the upper part of the Méndez shale (A. mayaroensis
subzone; lower part) in the Tampico area. It has been
noted in ‘Texas in the Corsicana marl of Travis and Navarro
Counties and in the Kemp clay of Falls County. In south-
TEXT-FIGURE 46
Globotruncana
ansseri
Bolli
PR 789.32
)
8.0° |60.0° 60.0°} 56.0°]42.2°]49.0°
3.0°}12.5°}16.0°] 12. zal abe L250 |e 4es ee: V2. 0e LO,
0. esas
)
°
)
tt. double | 9 956]0.070)0. 0.042] 0.0 | 0.028]0.084] 0.04
eel at D
Ht. double
0.0
:
(=) o
+ Is 5
f) °
°
a -
fo)
Double keel
2
All measurements in millimeters.
* + = double keeled early stage present.
western Arkansas G. gansseri has been observed in the Arka-
delphia marl of Hempstead County. Elsewhere in North
America, G. gansseri has been observed by Olsson (1964, p.
166) in the Navesink, Redbank, and Mt. Laurel formations
of New Jersey. Bronnimann and Brown (1956, p. 550)
recorded G. gansseri from the Prairie Bluff chalk of Ala-
bama.
TEXT-FIGURE 47
@ Globotruncana gansseri Bolli
@ Duplicate or near duplicate measurement
°
0.6 ©
=
= —
2 e °
= +
f=)
°
0.5-
e
e
e
14 ee ee ee ee ee L i ee
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 343
G. gansseri was noted in the West Indies in the Via
Blanca formation of Cuba by Bronnimann and _ Rigassi
(1964, pp. 261, 280) , in the Rio Yauco formation of Puerto
Rico by Pessagno (1960, p. 102), and in the Guayaguayare
formation of Trinidad by Bolli (1951, pp. 196, 197; 1957,
p- 54). In South America G. gansseri was recorded by Gan-
dolfi (1955, pp. 68, 69, 72) from the Colon formation of
Colombia.
In Europe it was figured by De Klasz (1953, pp. 235,
236) from the Maestrichtian of Bavaria under the name of
Globotruncana sp. 2 and has been recorded by Bolli and
Cita (1962, p. 752) from the Maestrichtian of Italy. G.
gansseri was noted in the Maestrichtian of Tunisa by Dal-
biez (1955, p. 167) and was figured by Tilev (1951, pp. 41-
46) under the name of G. lugeoni Tiley from the Mae-
strichtian of Turkey. It was also recorded from the
Maestrichtian of Australia by Edgell (1957, p. 113) under
the latter name. Hamilton (1953, p. 232) recorded and
figured G. gansseri from the Mid-Pacific guyot area.
G. gansseri thus seems to have been distributed in the
Boreal, Tethyan, and Austral faunal provinces during
Maestrichtian times.
Globotruncana hilli Pessagno, n. sp.
Plate 64, figures 9-14; 21-23; Plate 94, figure 1; Plate 97, figure 7
Description.—Test small trochospiral, relatively plani-
form both spirally and umbilically; consisting of two and
one-half to three whorls of chambers which slowly expand
in size; five chambers in last whorl. Chambers in early
whorls and first several chambers of posterior part of final
whorl spherical lacking double keel; remaining chambers
forming anterior part of final whorl abruptly truncated
peripherally by wide double keel of G. linneiana type; im-
perforate peripheral band or weak double keel developed
in anterior, but not posterior portion of preceding whorl.
Chambers petaloid in shape spirally; separated by curved,
depressed to slightly elevated sutures which usually lack
beads. Chambers umbilically subrectangular in shape; sep-
arated by depressed, slightly curved sutures. ‘Test wall finely
spinose throughout. Umbilicus wide and shallow, covered
by tegilla with intralaminal and infralaminal accessory aper-
tures. Primary aperture, interiomarginal, umbilical in posi-
tion. Outer wall radial hyaline perforate except for fine
spines and keel. Spines ultragranular hyaline. Keel radial
hyaline imperforate and ultragranular hyaline imperforate
(‘variety” of type 2; Text-figure 40) ; ultragranular hyaline
outer portion of spiral and umbilical rims poorly developed.
Tegilla and septal walls microgranular hyaline perforate.
TEXT-FIGURE 48
ras
Je
EXerZ Om
TX 291-C
PE 945 *
TX 291-C
TX 291-C
Globotruncana
PE 1027
OF252) ORS 79510:
D=D
_yr ]0-196 Jo. 205 jo.
0.056 j0.070
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| uw |o-296|
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nies K9.0°|
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S || SC
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=
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rary
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=
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double
ne at D
double
we aye ID)! AOE
OE LAT |e
i=)
i
—
Nh
All measurements in millimeters
*“ = paratypes.
Remarks.—G. hilli was most likely derived from G. lin-
neiana (d’Orbigny) by the enlargement of the latter form’s
Archacoglobigerina stage of development and the restric-
tion of its double keel to the anterior part of its test. G.
hilli differs from G. linneiana (1) by the small size and
me PALAEONTOGRAPHICA AMERICANA (V, 37)
finely spinose nature of its test; (2) by its ereatly enlarged
Archacoglobigerina stage of development; (3) by the pos-
session of a double keel only in the anterior portion of the
final whorl and the possession of an imperforate peripheral
band or weakly developed keel only in the anterior portion
of the preceding whorl; and (4) by the depressed nature of
its sutures both spirally and umbilically.
Form analysis data for G. hilli, n. sp. are presented in
Text-figure 48.
This species is named for R. T. Hill in honor of his
pioneering work on the stratigraphy of the Gulf Coastal
Plain area of North America.
Type locality —TX 291-C. ‘Taylor formation (“Upper
Taylor marl” member) . Buff calcareous mudstone collected
from ditch crossing State Route 73; 2.4 miles east of inter-
section of Route 73 with Farm Road 737 in town of Prairie
Hill, Limestone County, Texas.
Deposition of types—The holotype and figured para-
types of G. hilli Pessagno, n. sp. will be deposited in the
collections of the U.S. National Museum, Washington,
D.C. Unfigured paratypes will be deposited in the Paleon-
tological Research Institution, Ithaca, New York.
Range.—G. fornicata—stuartiformis assemblage zone, G.
elevata subzone (G. calcarata zonule) to R. subcircumnodi-
fer subzone (G. lapparenti s.s. zonule insofar as known) .
Occurrence.—In Mexico G. hilli, n. sp. occurs sparsely
in the common in the
Wolfe City sand of McLennan County; the “Upper ‘Taylor
marl” of Travis and Limestone Counties; the Upson clay of
Maverick County; and the Neylandville marl of Delta
County. In Arkansas G. hilli, n. sp. occurs in the Ozan for-
mation, the Annona chalk, and the Marlbrook marl.
Méndez shale. In Texas it is
Globotruncana lapparenti Brotzen
Plate 71, figures 6-13; Plate 97, figures 8, 9
1918. Globotruncana linnei d’Orbigny, de Lapparent, Mém. Carte
Géol. France, pp. 1-17, pl. 1, figs. 1, 7 (mot figs. 2-4; not pl. 2,
fig. 2; pl. 6, figs. 2, 3; pl. 8 (part) ; pl. 9, figs 2, 3 (mot fig. 6) ;
tfs. 1, 3 (p. 4) (not 5d); tf. 2 (p. 5): figs. a, d, m-n (not figs.
b-c, e, g, i-j; Pfigs. f, k-1).
1936. Globotruncana lapparenti Brotzen, Sver. Geol, Unders., Ser. C,
No. 396 (Ars. 30, No. 3, pp. 175, 176 (tf. 2 (p. 5): fig. n of De
Lapparent (1918) (selected herein as lectotype; tf. 2 (p. 5), fig.
m selected herein as paralectotype) .
1945. Not Globotruncana lapparenti lapparenti Brotzen, Bolli, Eclogae
Geol., Helv., vol. 37, No. 2, pp. 230, 231, text-fig. ‘1: figs. 15,
16; pl. 9, fig. 11.
1950. Globotruncana (Globotruncana) lapparenti Brotzen, Reichel,
Eclogae Geol. Helv., vol. 42, No. 2, p. 63, pl. 16, fig. 9; pl. 17,
fig. 9.
1951. Not Globotruncana lapparenti lapparenti Brotzen, Bolli, Jour.
Paleont., vol. 25, No. 2, pp. 193, 194, text-fig. 1: a (only) .
1953. Globotruncana lapparenti Brotzen, Subbotina (part), Trudy,
Vses. Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76,
p- 178, pl. 7, figs. 2a-c; not la-c, 3a-c, da-c, 5a-c.
|
1954. Not Globotruncana lapparenti lapparenti Brotzen, Hagn and |
Zeil, Eclogae Geol. Helv., vol. 47, No. 1, pp. 39-42, pl. 3, fig. 3;
pl. 6, figs. 5, 8.
1955. Globotruncana lapparenti longilocula Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, pl. 1, figs. la-c.
Globotruncana (Globotruncana) lapparenti lapparenti Brotzen,
Edgell, Micropaleont., vol. 3, No. 2, p. 113, pl. 1, figs. 7-9.
1957. Globotruncana linnei (d’Orbigny), Sacal and Debourle (part) ,
Soc. Géol. France, n. sér., Mém. No. 78, p. 61, pl. 26, figs. 8,
10, 218; not figs. 7, 9, 14-17.
Not Globotruncana lapparenti lapparenti Brotzen. Klaus, Eclo-
gae Geol. Helv., vol. 52, No. 2, p. 822, pl. 8, figs. 2a-c.
Globotruncana (Globotruncana) lapparenti lapparenti Brotzen,
Pessagno, Micropaleont., vol. 8, No. 3, p. 360, pl. 3, figs. 1-3.
Emended definition.—Test trochospiral, somewhat spI-
roconvex. (mean T’X/TX value for 19 specimens—0.72;
Table 2), 4-5 chambers in final whorl, truncated peripher-
ally by a well-developed double keel. Chambers spirally
petaloid, separated by raised, beaded, curved sutures. Cham-
bers umbilically, subrectangular, separated by elevated,
raised curved sutures which are often beaded. Chamber sur-
faces exclusive of sutures usually lacking rugosities. Um-
bilicus relatively deep and covered by a spiral system of
tegilla with intralaminal and infralaminal accessory aper-
tures. Primary aperture, interiomarginal, umbilical in posi-
tion. Outer wall radial hyaline, perforate except for keel
which is both radial hyaline and ultragranular hyaline, im-
perforate (“variety” of type 2, Text-figure 40). Septal
walls and tegilla microgranular hyaline, finely perforate.
Remarks.—The identification of this species has been
hampered by the fact that Brotzen described it in syntypic
series and cited numerous of De Lapparent’s (1918) figures
as syntypes. To stabilize the taxonomic status of G. lappar-
enti Brotzen, a lectotype (tf. 2, figure n, p. 5, De Lapparent,
1918) and a paralectotype (tf. 2, figure m, p. 5, De Lap-
parent, 1918) have been selected herein. Although a few of
Brotzen’s syntypes (e.g. tfs. 1, 3, p. 4, De Lapparent, 1918)
are drawings of free specimens, the drawings are poor and
hardly clarify the identification of G. lapparenti s.s. How-
ever, the drawings of De Lapparent’s sectioned specimens
are remarkably accurate in their detail and should leave
little doubt concerning the identification of this species in
thin-section. ‘The specimens figured herein in Plate 71 (figs.
6-13) correlate closely externally with the sectioned lecto-
type and paratype. The sectioned specimens figured in
Plate 97 (particularly fig. 9) herein are from the same
horizon as the free specimens figured in Plate 71.
G. lapparenti s.s. Brotzen (emended herein) is most
easily confused with G. linneiana (d’Orbigny). It differs
from this latter species largely by having a narrower double
keel (mean sum of heights of double keel at D and D’ for
19 specimens of G. lapparenti s.s.—0.136 mm.; for 27 speci-
mens of G. linneiana—0.230 mm.) . Form analysis measure-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 345
TEXT-FIGURE 49
Globotruncana
Brotzen
) it
ae aie > 0.056 (02 070 j0.084 ]0.070] 0.050) 0.119
gee 0.070}0.070
a et 0.126 }0.140 {0.126
All measurements in millimeters.
* = Lectotype selected herein (de Lapparent figure n).
**k = Paralectotype selected herein (de Lapparent figure m).
*xk = Transitional to G. linneiana (d'Orbigny)
ments for sectioned free specimens of G. lapparenti s.s. are
included in Text-figure 49. The writer separated G. lap-
parenti from G. linneiana on the basis of the first standard
deviation of the sum of their keel heights (cf. Table 2; Text-
figure 50). Text-figure 50 is a scatter plot of the T’X/TX
values and the sum of the keel heights values of G. lappar-
enti s.s. and G. linneiana. Specimens having sum of keel
height values greater than 0.164 mm. and less than 0.182
are considered transitional herein.
Numerous sectioned double-keeled species were illus-
PE 899
TX 29l-c
- 22410.
0.112]0.140 J0.098)0.
-07 700.084 [o. 070)0.
‘[22.0° ps.0" 2.0"
w °
9S
°
(=i
A)
°
°
EN EO
.0°}] 21.0°] 24.0°] 24.0°] 23. aa oe
.154] 0.196] 0.252
E seem
aH
trated by De Lapparent (1918, p. 5) in Text-figure 2: figs.
a-f. The writer’s interpretation of these figures is as follows:
a=G. lapparenti s.s. Brotzen
b=G. ventricosa White
c=M. angusticarenata (Gandolfi)
d=G. lapparenti s.s. Brotzen
e=G. sp. aff. G. bulloides Vogler
f=G. sp. aff. G. lapparenti s.s. Brotzen
g=G. linneiana (d’Orbigny)
h=G. sp. aff. G. lapparenti s.s. Brotzen
546
i=G. ventricosa White
j—G. contusa Cushman (=“Mutation caliciforme” de Lap-
parent)
k=?
l=?
m—G. lapparenti s.s. Brotzen (paralectotype selected here-
in).
n—G. lapparenti s.s. Brotzen (lectotype selected herein) .
Measurements of the sectioned specimens figured by
Bolli (1945) in text-figure 1: figure 15 (not 16) and in
plate 9, figure 11 as G. lapparenti lapparenti indicate that
Bolli’s form is assignable to G. linneiana (d’Orbigny) . The
specimen figured in text-figure 1: figure 16 may represent
an aberrant form of G. linneiana. Measurements from the
microphotograph in plate 9, figure 11 are shown in Text-
figures 49 and 50 herein.
The writer examined the holotype of G. lapparenti
longilocula Gandolfi (1955) (No. 20826 PRI) and found
this form to fall within the limits of G. lapparenti Brotzen
s.s. (as emended herein) . It thus is treated as a junior syno-
nym of the latter species.
The specimens figured as G. lapparenti Brotzen s.s. by
Haen and Zeil (1954) and by Klaus (1960) from the Lower
Turonian of the Bavarian Alps and the Upper Turonian
of Switzerland are most likely referable to Marginotruncana
coronata (Bolli) or angusticarenata
(Gandolfi) unless these strata have been reworked. No true
Globotruncanidae exist below strata of Santonian or Late
Coniacian age in the Western Hemisphere.
G. lapparenti Brotzen s.s. is one of the basic species of
Globotruncana s.s. It is believed to have evolved from an
Archaeoglobigerina ancestor during Early Santonian times.
As indicated in Text-figure 35, it gave rise to G. linneiana
Ma rein otruncana
(dOrbigny) and G. spinea Kikoine. ‘The former species in
turn gave rise to G. ventricosa White, G. rosetta (Carsey) ,
and other double-keeled species.
Range.—G. bulloides assemblage zone, M. concavata
subzone to G. fornicata—stuartiformis assemblage zone, R.
subcircumnodifer subzone (G. lapparenti s.s. zonule) . This
species seems to have enjoyed its greatest abundance during
Santonian and Early Campanian times. It is common in
Late Campanian strata and becomes progressively rarer in
Early Maestrichtian strata.
Occurrence.—In Mexico G. lapparenti s.s. occurs in the
Early Santonian and Early Campanian portions of the San
Felipe formation in all of the outcrop areas indicated in
Textfigure 2. It likewise occurs in the Early Campanian to
Early Maestrichtian portions of the Méndez shale in all of
the outcrop areas indicated in the same text-figure.
PALAEONTOGRAPHICA AMERICANA (V, 37)
In Texas G. lapparenti s.s. has been observed in the
Santonian portion of the Austin chalk in Kinney, Travis,
McLennan, and Dallas Counties and in the reworked
Early Campanian upper portion of the Austin chalk in
Dallas County. It likewise occurs in the Taylor formation:
(1) in the “Lower Taylor marl” member of ‘Travis, McLen-
nan, and Dallas Counties; (2) in the Wolfe City sand mem-
ber of McLennan County; (3) in the Pecan Gap chalk
member of McLennan County; and (4) in the “Upper
Taylor marl” member of Travis and McLennan Counties.
In addition it is known from the Early Maestrichtian por-
tion of the Upson clay in Maverick County and the Ney-
landville marl of Navarro and Delta Counties.
In southwestern Arkansas G. lapparenti Brotzen S.s.
occurs throughout the Campanian and Early Maestrichtian
portions of the section in the Brownstown marl; Ozan for-
mation; Annona chalk; Marlbrook marl; and Saratoga
chalk (cf. Text-figure 2) .
G. lapparenti s.s. occurs in the Parguera limestone,
Cariblanco, and Rio Yauco formations of Puerto Rico (cf.
Pessagno 1960, 1962) and in the Naparima Hill and Guay-
aguayare formations of Trinidad (cf. Bolli, 1957) . It is also
known from the Upper Cretaceous of Colombia. Recently,
the writer has observed it in thin-sectioned Campanian
limestones from Panama.
G. lapparenti s.s. is also known from the Upper Cre-
taceous of France, Switzerland, Russia, and Australia.
Globotruncana linneiana (d’Orbigny)
Plate 72, figures 1-4; 7-9; Plate 97, figures 11-13
1839. Rosalina linneiana d’Orbigny, in Ramon de La Sagra, Historie
physique et Naturelle de I’Ile de Cuba; A. Bertrand, Paris,
France, p. 110, vol. 8, pl. 5, figs. 10-12 (plates published sep-
arately) .
1854. Not Rosalina canaliculata Reuss, K. Akad. Wiss. Wien. Math.—
Natur. KI., Denkschr., Bd. 7, p. 70, pl. 26, figs. 4a, b.
1893. Pulvinulina tricarinata Quereau, Beitr. Geol. Karte Schweiz,
Bern, No. 33, p. 89, pl. 5, figs. 3a-c (Lectotype, pl. 5, fig. 3a).
1918. Rosalina linnei d’Orbigny, de Lapparent, Mém. Carte Géol.
France, pp. 1-17, tf. 2, fig. g (only).
1928. Globotruncana canaliculata (Reuss) , White, Jour. Paleont., vol.
2, No. 4, pp. 282-287, pl. 38, figs. 3a-c.
1936. Globotruncana linnei (d’Orbigny), O. Renz (part), Eclogae
Geol. Helv., vol. 29, No. 1, pl. 8, fig. 7, text-figs. 28, 29, 31, 32,
33, 34; not 30 (no pagination) .
1941. Globotruncana linnei typica (d’Orbigny), Vogler, Palaeonto-
graphica Suppl. Bd. 4, Abt. 4, p. 286, pl. 23, figs. 12-21.
1941. Globotruncana linnei tricarinata (Quereau), Vogler (part),
Palaeontographica Suppl. Bd. 4, Abt. 4, p. 287, pl. 23, figs. 22,
723, 224, 25, 27, 228, 31; not 26, 29, 30.
1945. Globotruncana lapparenti lapparenti Brotzen, Bolli, Eclogae
Geol. Helv., vol. 37, No. 2, p. 230, pl. 9, fig. 11; text-fig. 1: fig.
15; ?fig. 16.
1945. Globotruncana lapparenti tricarinata (Quereau), Bolli (part) ,
Eclogae Geol. Helv., vol. 37, No. 2, pp. 232, 233, text-fig. 1: fig.
19, ?fig. 20; Ppl. 9, fig. 13.
|
|
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 347
1946. Globotruncana canaliculata (Reuss), Cushman (part), Wiss
Geol. Sur., Prof. Paper, No. 206, p. 149, pl. 61, figs. 18a-c; not
I7a-c.
1951. Globotruncana canaliculata (Reuss), Bandy, Jour. Paleont., vol.
25, No. 4, p. 509, pl. 75, figs. 2a-c.
1953. Globolruncana linneiana (d’Orbigny) , Subbotina, Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., new ser., vol. 76, p.
176, pl. 5, figs. 7a-c; 8a-c; ?9a-c; pl. 6, figs. la-c; 2a-c; 3a-c; da-c.
1953. Globotruncana lapparenti Brotzen, Subbotina (part), Trudy,
Vses. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p.
178, pl. 7, figs. 4a-c; not pl. 6, figs. la-c; 2a-c; 3a-c; 5a-c.
1955. Globotruncana tricarinata columbiana Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 20, pl. 1, figs. 3a-4e.
1956. Globotruncana linneiana (d’Orbigny), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, pp. 540-542, pl. 20, figs.
13-17; pl. 2i, figs. 16-18.
1956. Globotruncana aspera Hofker «(part), Neues Jahrb. Geol. Pal-
eont., Abh. 103, p. 327, fig. 14 (part), fig. 15.
1956. Globotruncana paraventricosa Hoftker, Neues Jahrb. Geol. Pal-
eont., Abh. 103, p. 328, figs. 17, 18.
1957. Globotruncana linnei (d’Orbigny), Sacal and Debourle (part) ,
Soc. Géol. France, n. sér., Mém. No. 78, p. 61, pl. 26, figs. 7, 9;
14-17; not figs. 8, 10, ?18.
1957. Globotruncana majzoni Sacal and Debourle, Soc. Géol. France,
n. sér., Mém. No. 78, p. 62, pl. 26, figs. 6, 21, 22.
1957. Globotruncana marginata (Reuss), Sacal and Debourle (part) ,
Soc. Géol. France, n. sér., Mém. No. 78, p. 59, pl. 26, fig. 3, 213;
not figs. 5, 12.
1957. Globotruncana (Globotruncana) cf. lapparenti Brotzen, Edgell,
Micropaleont., vol. 3, No. 2, pl. 1, figs. 4-6.
1959. Globotruncana linneiana (d’Orbigny), Ayala, Univ. Nacional
Aut. México, Instit. Geol., Paleont. Méxicana, No. 4, p. 24, pl. 4,
figs. 4-6.
1961. Globotruncana linneiana (d’Orbigny), Graham and Clark, Contr.
Cushman Found. Foram. Res., vol. 12, pt. 3, p. 113, pl. 5, figs.
lla-c.
1961. Globotruncana linneiana tricarinata (Quereau), Graham and
Clark, Contr. Cushman Found. Foram. Res., vol. 12, pt. 3, p.
112, pl. 5, figs. 8a-c.
1962. Globotruncana lapparenti lapparenti Brotzen, Herm, Bayer.
Akad. Wiss., Math.-Nat. KI., Abh., n. ser., No. 104, pp. 82-84, pl.
6, fig. 2.
1962. Globotruncana tricarinata (Quereau), Herm, Bayer. Akad.
Wiss., Math.—Nat. KI., Abh., n. ser., No. 104, pp. 93, 94, pl. 6,
fig. 4.
1962. Globotruncana (Globotruncana) lapparenti linneiana (d’Or-
bigny) , Pessagno, Micropaleont., vol. 8, No. 3, p. 360, pl. 3,
figs. 7-9.
1962. Globotruncana linneiana linneiana (d’Orbigny) , Barr, Paleontol-
ogy, vol. 4, pt. 4, pp. 571, 572, pl. 69, figs. 7a-c; pl. 72, fig. 5.
1962. ? Globotruncana linneiana tricarinata (Quereau) , Barr, Paleon-
tology, vol. 4, pt. 4, pp. 573, 574, pl. 70, figs. 2a-c.
1962. Globotruncana (Globotruncana) tricarinata (Quereau), Berg-
gren, Stockholm Contr. Geol., vol. 9, No. 1, pp. 64-67, pl. 10,
figs. 3a-c.
1963. Globotruncana linneiana (d’Orbigny) , Bronnimann and Rigassi,
Eclogae Geol. Helv., vol. 56, No. 1, pl. 17, figs. 5a-c (no pagina-
tion).
1964. Globotruncana linneiana (d’Orbigny), Olsson (part), Micro-
paleont., vol. 10, No. 2, pp. 166, 167, pl. 7, figs. 6a-c; 8a-c; not
7a-c.
1964. Globotruncana tricarinata (Quereau), Olsson, Micropalcont.,
vol. 10, No. 2, pp. 171, 172, pl. 5, figs. da-c; 5a-c.
1964. Globotruncana linneiana (d’Orbigny), Martin, Jahrb. Geol.
Bund., Sond. 9, p. 81, pl. 10, figs. 3a-c. ;
1964. Globotruncana linneiana tricarinata (Quereau), Martin, Jahrb.
Geol. Bund., Sond. 9, p. 81, pl. 10, figs. 2a-c. :
Description.—Test low trochospire, planiform both
spirally and umbilically, abruptly truncated peripherally
by a wide double keel; periphery quite lobulate. Two
whorls of chambers, approximately the same size in final
(1) = Globotruncona lapporenti s. s. Brotzen of Bolli, 1945
1945, pl. 9, fig. 11
TEXT-FIGURE 50 (2) = Pulvinulino tricarinata Quereau, 1893, pl. 5, fig. 3a
(3) = Globotruncana lapparenti s. s. Brotzen (de Lapporent,
© = Globotruncana linneiana (d’Orbigny) 1918, fig. n; Lectotype selected herein)
@ = Globotruncana lapparenti_ Brotzen (4) = Globotruncana lapparenti s. s. Brotzen (de Lapparent
@©= Duplicate measurement fig. m; paralectotype selected herein.)
_#= Transitional
0-2
0.300
°
° °
° ° °
= 0.250}
= o- | °
z
= oOo °
f=}
=; ° °
a 0.200F ° © O}
K |__ Ist Ston. Dev. = 0.182 (G. linn.) a ° q
ad
a Ist Stan. Dev. = 0.164 (G. lapp.) “ cCE
= e
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ra 2 o
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= o-4
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0.050}-
L ! I ei eS Al wot ee
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T X/TX
whorl; early chambers of final whorl considerably larger
than the chambers of the preceding whorl (final whorl
somewhat greater than 2X diameter of preceding whorl) ;
five to seven chambers in final whorl. Chambers in final
whorl petaloid, separated by raised, curved, highly beaded
sutures spirally; chambers in final whorl subrectangular,
separated by raised, straight to slightly curved, beaded su-
tures umbilically. Umbilicus moderately large, often flanked
by prominent beaded, umbilical shoulder and covered by a
spiral system of tegilla showing infralaminal and intrala-
minal accessory apertures. Primary aperture interiomar-
ginal, umbilical in position. Outer wall radial hyaline per-
forate except for double keel and beads. Double keels pre-
dominently radial hyaline, imperforate with slight overlay
of ultragranular hyaline imperforate calcite on spiral and
umbilical rims (variety of type 2; Text-figure 40) ; inter-
rim area consisting of high (wide) , attenuated bar of radial,
hyaline calcite traversed by rare pores. Beads ultragranular
hyaline imperforate. Septal walls and tegilla microgranular
hyaline, finely perforate.
Remarks.—A neotype of Rosalina linneiana d’Orbigny
was erected by Bronnimann and Brown (1956) from Re-
cent beach sands near Habana Bay, Cuba. The writer
examined this neotype deposited in the collections of the
U.S. National Museum during the course of this study.
G. linneiana (d’Orbigny) is gradational with G. lap-
parenti Brotzen. G. linneiana can be separated from the
latter species by virtue of the fact that it has a much wider
548
(higher) double keel peripherally. A discussion of the
separation of these two species on this basis has been pre-
sented herein under G. lapparenti s.s. (see also Text-
figure 50) .
G. linneiana (d’Orbigny) is also transitional into G.
ventricosa White but can be separated from G. ventricosa
by its lower T’X/TX values. The mean T’X/TX value for
27 measured specimens of G. linneiana—0.81 whereas the
mean T’X/TX value for 13 measured specimens of G. ven-
tricosa=2.65 (see Table 2; Text-figures 50, 51, 60). The
separation of these species herein is based on their first
standard deviations. Thus, T’X/TX=1.05 is considered
the upper limit of G. linneiana and T/X/TX=1.32 is con-
sidered the lower limit of G. ventricosa. Specimens having
T’X/TX values greater than 1.05 and less than 1.32 are
considered transitional. Workers will find that most of the
specimens falling within this range are impossible to assign
to either species on the basis of their external morphology.
Globotruncana tricarinata (Quereau, 1893, p. 89, jell, &
figs. 3a-d) is regarded as a junior synonym of G. linneiana
(d'Orbigny). The former species has long been one of
the most problematical species in the Upper Cretaceous
largely because it was described in thin-section and in syn-
typic series. To stabilize the taxonomic status of this species,
fig. 3a (pl. 5) of Quereau is designated the lectotype of G.
tricarinata. The remainder of Quereau’s figured speci-
mens (figs. $b-d) are poor and fragmental. For this reason,
paralectotypes have not been selected. Form analysis data
for the sectioned lectotype of Pulvinulina tricarinata Quer-
eau are presented in Text-figures 50 and 51 herein. The
reader can see that the lectotype of P. tricarinata falls well
within the limits of G. The so-called “third
keel” of G. tricarinata is little more than a slightly raised
umbilical shoulder. It is developed only on the anterior
portion of the test and does little to increase the convexity
of the umbilical side of the test. In fact, the T7X/TX value
of the lectotype is 0.66 and less than the mean value for G.
linneiana (0.81). The writer feels that the majority of
specimens that various workers have attributed to G.
tricarinata (Quereau) are either assignable to G. linneiana
or to transitional forms between G. linneiana and G. ventri-
cosa (having T’X/TX values greater than 1.05 and less
than 1.32).
The specimens figured by Bolli (1945, 1951) as G.
lapparenti lapparenti Brotzen have wide double keels and
are ungestionably assignable to G. linneiana (cf. Text-
figure 50) .
The writer has found that most of the specimens fig-
(Reuss)
linneiana.
ured in literature as G. canaliculata are either
PALAEONTOGRAPHICA AMERICANA (V, 37)
assignable to M. coronata (Bolli), G. lapparenti s.s. Brotzen, )
or to G. linneiana (d’Orbigny) . For example, the specimens |
figured by Cushman (1946, pl. 61, figs. 17a-c; 18a-c) as G.—
canaliculata (Reuss) are referrable to G. lapparenti s.s.
Brotzen and to G. linneiana (d’Orbigny) (figs. 17a-c=G.
lapparenti s.s.; figs. 18a-c=G. linneiana) .
The problem of the identity of Rosalina canaliculata
Reuss is a complex one. It has been resolved herein by
the selection of a neotype (see Marginotruncana canalicu-
lata (Reuss) .
Sectioned microspheric specimens of G. linneiana ap-
pear to show a G. lapparenti s.s. early stage of development
whereas sectioned megalospheric specimens (cf. Plate 97,
figs. 11-13) omit this stage. It is likely that G. linneiana
evolved from a G. lapparenti s.s. ancestor through minor
dorsal and spiral flattening and obtaining a wide double
keel peripherally. G. linneiana gave rise to G. ventricosa
White through progressive umbilical inflation. A suppressed
G. linneiana stage of development is visible in sectioned
specimens of G. ventricosa (cf. Plate 95, figs. 10, 11). Other
species arising from G. linneiana are indicated in ‘Text-
figure 35.
Globotruncana linneiana (d’Orbigny) is nearly homeo-
morphic for Marginotruncana pseudolinneiana Pessagno, n.
sp. The differences between these two species have been
cited herein under M. pseudolinneiana,
Range.—G. fornicata—stuartiformis assemblage zone,
A. blowi subzone (P. glabrata zonule) to R. suwbeircum-
nodifer subzone (R. subpennyz zonule) .
Mexico G. linneiana is common to
abundant throughout the Campanian and Early Maestrich-
tian portions of the Méndez shale. It is rare in the Early
Campanian portion of the San Felipe formation.
In Texas G. linneiana has been observed in the Early
Campanian (reworked) portion of the Austin chalk in
Dallas County. In the Campanian Taylor formation it oc-
curs in the “Lower Taylor marl” member of McLennan,
Travis and Dallas Counties and in the “Upper ‘Taylor
marl’ member of Travis and Limestone Counties. This
species has likewise been observed in the “Neylandville
marl” of Delta County (Locality 52 of Cushman, 1946, p. 3)
in a fauna which is assignable to the G. calcarata zonule.
Elsewhere in North America G. linneiana was recorded
by Bandy (1951) under the name of G. canaliculata from
the Campanian (?) of San Diego County, California; by
Graham and Clark (1961) from the Upper Cretaceous
(Campanian ?) of Merced County, California; by Martin
(1964) from the Marlife formation of Fresno County, Cali-
fornia; and by Olsson (1964) from the Mt. Laurel—Nave-
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()5.5)5)
0.50
0.112)0.154]0.112}0
4}0.098]0.139]0.168]0
0.224
0.420}0
54
8
0.210]0.293]0.280]0.225]0. 267
aul
5}0.23
0.83
281
ojo.
0.238 }O
0.280 }O
v9 edhy,
xe LT6 dd
»
= fais ac a = al =
5, | — (su8930,P) >] el al =] el oe] x[Bclecls3
= BueTouuTT Saen|eonwenl) = | se |) cea Seo
oy oo = || s=,|| es x SSeS OES ee
i eueouni30q0T59 a as a 3 cx a ailna a
E =] =] aI s rl]: @ v ”
i sh Be a er Yy voy Hy ao] dv
= xe || sce || eo || ee =e esl [aka
Lil
ventricosa White
of Bolli 1945, pl. 9, fig.
** = Pulvinulina tricarinata Querean (1893, ibn 5 tials, SMa
Brotzen
Orbigny) transitional to G.
s.s.
arenti
linneiana (d'
ace
All measurements in millimeters.
Tekk
* = G. la
tit Ps nly a ARE Oye, Ss en a
eines shige ote ape ripe t ba is ——s
ae & Piifea by PE : im Ted y\o a7SP ss. te ioe ~ ai
x acai | catia Uh i
7 mot ie V4l, oeks tl Wri dae cba Se yt
ee fees
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 349
sink formation of Delaware and the Mt. Laurel and Mar-
shallLown formations of New Jersey. The writer has recently
seen this species in thin-sections of Campanian and Early
Maestrichtian limestones from Panama.
In the West Indies G. linneiana is well known from
the Upper Cretaceous of Cuba. D’Orbigny’s type specimen
originally came from Recent beach sands along Habana
Bay containing reworked Upper Cretaceous fossils. The
neotype selected by Bronnimann and Brown (1956) was
extracted from Recent beach sands in the same area. Bron-
nimann and Rigassi (1964, pp. 213-280) noted G. linneiana
in the pre-Via Blanca beds, the Via Blanca formation, and
in the Penalver formation of the Habana area in Cuba.
Ayala (1959) noted this species from the Campanian—Early
Maestrichtian of Haiti. Pessagno (1962, p. 360) noted it in
the Late Campanian—Early Maestrichtian Rio Yauco forma-
tion of Puerto Rico. Recent work by the writer also indi-
cates that G. linneiana also occurs in the Campanian—Early
Maestrichtian Parguera limestone.
G. linneiana is common in strata of Campanian and
Early Maestrichtian age in Eurasia. It is known (under
various names, see synonymy) from France, Switzerland,
Austria, the Isle of Wight, and Russia.
Edgell (1957) figured this species under the name of
Globotruncana (Globotruncana) cf. lapparenti from the
Upper Cretaceous of Australia.
G. linneiana seems to have been widely distributed in
Late Cretaceous seas in the Boreal, Tethyan, and Austral
faunal provinces.
Globotruncana loeblichi Pessagno, n. sp.
Plate 73, figures 1-4; Plate 97, figure 10
Description.—Test trochospiral, planiform, compressed
spirally and umbilically (spiral surface often concave) ;
lobulate peripherally with medium-sized double keel of G.
linneiana type; keels diverging and dichotomous (cf. Plate
73, fig. 4). Spiral rim of double keel often spinose in early
part of final whorl. Test comprised of two whorls of cham-
bers which expand rapidly in size in the first whorl and more
slowly in the final whorl; four to five chambers in the final
whorl. Chambers in final whorl petaloid in shape spirally;
subrectangular in shape umbilically; separated by curved,
elevated, beaded sutures spirally and by straight to slightly
curved, elevated, beaded sutures, umbilically. Test show-
ing some rugosities on spiral surface of final whorl par-
ticularly on early chambers. Umbilicus wide, shallow, covy-
ered by tegilla showing infralaminal and intralaminal ac-
cessory apertures. Primary aperture interiomarginal, umbili-
cal in position. Outer wall radial hyaline perforate except
TEXT-FIGURE 52:
is)
G
w
(3)
G
=
H
y
°
Qa
°
re
oO
U-U'
1x
Tx
loeblichi,
n.
Ht. double
All measurements in millimeters
for keels, beads, rugosities, and peripheral spines. Kecls
ultragranular hyaline imperforate and radial hyaline im-
perforate (‘‘variety” of type 2, Text-figure 40) ; rugosities,
beads, and peripheral spines ultragranular hyaline imper-
forate. Septal walls and tegilla microgranular hyaline,
finely perforate.
350 PALAEONTOGRAPHICA AMERICANA (V, 37)
Remarks.—G. loeblichi Pessagno, n. sp. is related phylo-
genetically to G. linneiana (d’Orbigny) (Text-figure 35) .
It differs from G. linneiana (1) by the thinner (less high)
nature of its double keels; (2) by the highly compressed na-
ture of its test along a spiral-umbilical apace (@)) Toy tie
dichotomous (diverging) nature of its double keels in
peripheral view; and (4) by the imbricate nature of its
chambers in peripheral view.
Form analysis data for sectioned free specimens of G.
loeblichi ave presented in Text-figure 52.
G. loeblichi, n. sp. is named after Alfred R. Loeblich,
Jr. in honor of his great contributions to the field of
micropaleontology.
Type locality—TX 375. Taylor formation (“Lower
Taylor marl” member) . Gray to buff calcareous mudstones
breaking with conchoidal fracture. Clay pit of Baron Brick
Company at Palmer, Ellis County, Texas. Sample collected
at base of pit (1962) ; 38 feet of exposure.
Range.—G. fornicata—stuartiformis assemblage zone,
A. blowi subzone (P. glabrata zonule) to G. elevata subzone
(G. calcarata zonule) in so fas as known.
Occurrence.—In Mexico G. loeblichi has been observed
in the Late Campanian portion of the Méndez shale in the
Tampico area at locality MX 82 (see Appendix) . In Texas
it has only been observed at its type locality in the Early
Campanian portion of the Taylor formation
Globotruncana nothi (Bronnimann and Brown)
Plate 67, figures 49; Plate 68, figures 6-8; Plate 96, figure 10
1955. Globotruncana fornicata ackermanni Gandolfi (part), Bull.
Amer. Paleont., vol. 36, No. 155, p. 42, pl. 2, figs. 6a-c, 7a-c;
not 5a-c (holotype) .
1956. Rugotruncana nothi Bronnimann and Brown, Eclogae Geol.
Helv., vol. 48, No. 2, p. 551, pl. 22, figs. 16-18.
1956. Marginotruncana pauperata Hotker, Neues Jahrb. Geol. Pal-
eont., Abh. 108, pp. 331, 332, fig. 21, 722.
1964. Globotruncana nothi (Bronnimann and Brown) , Olsson, Micro-
paleont., vol. 10, No. 2, p. 168, pl. 4, figs. 9a-c.
Description.—Test trochospiral, spiroconvex, truncated
peripherally by a double keel; keel rims parallel on pos-
terior portion of each chamber, sharply divergent on an-
terior part of each chamber; divergent double keels par-
ticularly well developed on last several chambers of final
whorl. Test comprised of two to two and one-half whorls
of chambers; five to seven chambers in last whorl. Early
chambers of last whorl considerably larger than final cham-
bers of preceding whorl; remaining chambers of final whorl
slowly expand in size. Chambers spinose and rugose spirally,
moderately flattened individually both spirally and umbili-
cally; peculiarly notched spirally and having a somewhat
imbricate appearance peripherally. Chambers spirally vary
between petaloid and crescent-shaped; chambers umbilically —
usually subrectangular in shape. Sutures raised, highly
beaded, curved spirally; straight to slightly depressed, rarely
beaded umbilically. Early whorl comprised of inflated glo-
bigeriniform chambers which may possess either an im-
perforate peripheral band or weak double keel or lack these
features altogether. Umbilicus moderately large, usually
lacking beaded umbilical shoulder; covered by spiral system
of tegilla with intralaminal and infralaminal accessory
apertures. Primary aperture interiomarginal, umbilical in
position. Outer wall radial hyaline, perforate except for
keels, spines, and rugosities. Keels radial hyaline imper-
forate and ultragranular hyaline imperforate (“variety” of
type 2, Text-figure 40). Coarse spines and rugosities ultra-
granular hyaline, finely perforate.
Remarks.—Bronnimann and Brown (1956) included
this species under Rugotruncana Bronnimann and Brown.
However, the writer restricts Rugotruncana to those species
showing rugosities arranged in a distinctive meridorial pat-
tern. G. nothi, though often rugose, shows no meridorial
arrangement of rugosities.
The writer examined the holotype of R. nothi Bronni-
mann and Brown at the U.S. National Museum, Washing-
ton, D.C. He also examined the holotype of G. fornicata
ackermanni Gandolfi (No. 20836) at the Paleontological
Research Institution, Ithaca, New York. The holotype of
G. fornicata ackermanni is not significantly different from
that of G. fornicata plummerae in appearance. It lacks di-
vergent double keels and shows rather vaulted chambers
spirally. The paratypes of G. fornicata ackermanni figured
by Gandolfi seem assignable to G. nothi (Bronnimann and
Brown). Marginotruncana pauperata Hofker is synono-
mous with G. nothi. Furthermore, its generic characteristics
clearly indicate that it should be placed with Globotrun-
cana and not with Marginotruncana (see emended defini-
tion of Marginotruncana herein) .
It is likely that G. nothi evolved from G. fornicata as
suggested in Text-figure 35.
Range.—G. fornicata—stuartiformis assemblage zone,
G. elevata subzone (G. calcarata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence—In the course of the present study G.
nothi has been observed in ‘the Late Campanian portion of
the Méndez shale of Mexico in the ‘Tampico area. In ‘Texas
this species occurs abundantly in the “Upper ‘Taylor marl”
member of the Taylor formation in Limestone County in
a rich fauna containing G. ventricosa, G. calcarata, and a
number of species indicative of the G, elevata subzone (G.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
calcarata zonule). In $.W. Arkansas it occurs in the Marl-
brook marl, in the Saratoga chalk, and in the Arkadelphia
marl.
Bronnimann and Brown (1965) originally described
G. nothi from the Late Maestrichtian (A. mayaroensis sub-
zone) of Cuba. Elsewhere in the Western Hemisphere G.
nothi has been recorded and figured by Olsson (1964) from
the Redbank formation of New Jersey and by Gandolfi
(1955, part) under the name of G. fornicata ackermanni
Gandolfi from the Colon formation of Colombia.
In Europe G. nothi has been recorded by Hofker
(1956) under the name of Marginotruncana pauperata Hol-
ker from the Maestrichtian of Holland.
Globotruncana plummerae Gandolfi
Plate 66, figures 3-8; Plate 96, figure 9
1955. Globotruncana fornicata plummerae Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 42, pl. 12, figs. 3a-c; 4da-c.
1955. Globotruncana fornicata ackermanni Gandolfi (part), Bull.
Amer. Paleont., vol. 36, No. 155, p. 42, pl. 2, figs. 5a-c; not
6a-c, 7a-c.
1963. Globotruncana fornicata Plummer,
Eclogae Geol. Helv.,
tion) .
1963. Globotruncana (Globotruncana) fornicata re Gandolfi,
Van Hinte, Jahrb. Geol. Bund., Sond. 8, p. 63, pl. 3, figs. la-c.
Bronnimann and
vol. 56, No. 1, pl. 17, figs. 3a-c,
Rigassi,
(no pagina-
Description.—Test (mean
T’X/TX value for seven measured specimens—0.255) with
prominent double keel which is reflected umbilically.
Chambers arranged in two to two and one-half whorls; ex-
pand greatly in size as added; to five chambers in
final whorl. Chambers in last whorl spirally elongate, cres-
cent-shaped, highly vaulted, separated by depressed, curved
sutures usually lacking beads; whorls
globigeriniform. subrectangular in
shape, slightly inflated, separated by depressed straight to
slightly curved sutures usually lacking beads. First two or
three spiral chambers of final whorl usually possessing
coarse spines and rugosities on their surfaces. Umbilicus
deep, lacking beaded umbilical shoulder, covered by spiral
system of tegilla with intralaminal and infralaminal acces-
sory apertures. Primary aperture, interiomarginal, umbili-
cal in position. Outer wall radial hyaline perforate except
for keels, spines, and rugosities. Keels radial hyaline and
imperforate (‘‘variety” of type 2;
Text-figure 40) ; coarse spines and rugosities ultragranular
hyaline, imperforate. Septal walls and tegilla microgranular
hyaline perforate.
trochospiral, —spiroconvex
four
chambers in early
Chambers umbilically
ultragranular hyaline,
Remarks.—G. plummerae Gandolfi is somewhat similar
to G. fornicata Plummer. It differs from the latter species
oo
Or
—
TEXT-FIGURE 53:
Globotruncana
lummer ae
Gandolfi
0.443 J0.448 }0.471 ]0.434
Angle X DU’
Angle xiDIaT
eu
0.0° 30.0" bo. O° 138) 50°
028
18.0° |26.0° |24.0° |18.0°
Angle XDU
ce a a
double
oe BE 1D)
Ht. double
keel at D'
All measurements in millimeters.
Note: T’X for specimen Pe 775 = 0.041.
T’X/TX for specimen Pe 775 = 0.20.
(1) by possessing vaulted, noncrenulate, spinose, chambers
spirally and (2) by possessing markedly depressed sutures
both spirally and umbilically. Both species possess elongate,
crescent-shaped chambers spirally, subrectangularly shaped
chambers umbilically, and umbilically reflected double
keels. As suggested in Text-figure 35 herein, it is likely that
G. plummerae evolved from G. fornicata largely via the
arching of the chambers spirally and the development of
depressed sutures. Gandolfi (1955, p. 39) likewise favored
the evolution of G. plummerae from G. fornicata. How-
ever, a possible phylogenetic link between this species and
G. bulloides Vogler should be further investigated.
c
352 PALAEONTOGRAPHICA AMERICANA (V, 37)
G. plummerae Gandolfi differs from G. nothi (Bronni-
mann and Brown) (1) by possessing highly arched cham-
bers spirally; (2) by showing a rapid expansion in chamber
size; and (3) by usually lacking raised beaded sutures
spirally.
Range.—G. fornicata—stuartiformis assemblage zone,
G. elevata subzone (P. elegans zonule) to R. subcircum-
nodifer (G. lapparenti s.s. zonule) insofar as known.
Occurrence.—This species has been observed in the
Late Campanian and Early Maestrichtian portions of the
Méndez shale of the Tampico area of Mexico. It also occurs
in deposits of the same age (Papagallos shale) north of
Mamulique Pass along the Mexico, D.F.—Nueyvo Laredo
Highway (Rt. 85).
In Texas, G. plummerae occurs in the middle to upper-
most portions of the Wolfe City sand in McLennan and
Falls County; in the Pecan Gap chalk of McLennan County;
and in the “Upper Taylor marl” of Travis and Limestone
Counties. It likewise has been observed in the Neylandville
marl of Navarro County and Delta County (Locality No.
52, Cushman, 1946, p. 3).
In southwestern Arkansas G. plummerae occurs in the
Annona chalk, the Marlbrook marl, and in the Saratoga
chalk.
This species was originally described by Gandolfi
(1955) from Colon shale of Colombia. It was figured by
Bronnimann and Rigassi (1963) under the name of G.
fornicata Plummer from the Campanian of Cuba.
Globotruncana rosetta (Carsey)
Plate 70, figures 9-12; Plate 73, figures 5-8; Plate 98, figure 14;
Plate 97, figures 19-23
1926. Globigerina rosetta Carsey, Univ. Texas Bull., 2612, p. 44, pl. 5,
figs. 3a-c.
1931. Globotruncana arca (Cushman), Plummer, Univ. Texas Bull.
3101, pl. 195, pl. 13, figs. 1la-c; not Ta-c, la-c; Ya-c.
1938. Globotruncana cretacea Cushman, Contr. Cushman Lab. Foram.
Res., vol. 14, p. 67, pl. 11, figs. 6a-c.
1946. Globotruncana cretacea Cushman, U.S. Geol. Sur., Prof. Paper,
No. 206, p. 151, pl. 62, figs. 7a-c.
1951. Not Globotruncana rosetta (Carsey), Bandy, Jour. Paleont., vol.
25, No. 4, p. 509, pl. 75, figs. 4a-c.
1953. Not Globotruncana rosetta (Carsey), Subbotina, Trudy, Vses,
Neft. Nauckno—Issled. Geol. Razved. Instit., n. ser., No. 76, p.
197, pl. 13, figs. 5a-c; Ga-c.
1953. Not Globotruncana rosetta (Carsey), Hamilton, Jour. Paleont.,
vol. 27, No. 2, p. 233, pl. 29, figs. 26-28.
1955. Not Globotruncana rosetta rosetta (Carsey), Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, pp. 66, 67, pl. 6, figs. la-c;
?text-figure 10.
1955. Globotruncana arca caribica Gandolfi, Bull. Amer. Paleont.,
vol. 36, No. 155, p. 64, pl. 5, figs. 5a-c.
1955. Globotruncana ventricosa ventricosa White, Gandolfi, Bull.
i Amer. Paleont., vol. 36, No. 155, p. 22, pl. 1, figs. 5a-c.
1956. Globotruncana rosetta (Carsey) , Bronnimann and Brown, Eclo-
gae Geol. Helv., vol. 48, No. 2, pp. 545, 546, pl. 21, figs. 11-13.
1959. Globotruncana rosetta (Carsey), Ayala (part), Univ. Nacional
Aut. México, Instit. Geol., Paleont. Mexicana, No. 4, p. 25, pl.
5, fig. 2; not pl. 5, fig. 3; not pl. 6, fig. 4.
TEXT-FIGURE 54:
Globotruncana
(Carsey)
PE 109
PR 789.00
PE 113
PR 799.00
PE 114
PR 789.00
PE 1142
TX
in
0.077] 0.0700. 098) 0.0
140] 0. [0.140]. 140} 0.0 }
39.0°| 44.04] 52.0" 50,0 7.0°) 43
:
11.0°) 16. 20.0° -
nm
2
Angle XD'U" .0
(0)
0°
2
44.0
0.2050 i i es
es
is l me
Ht. double
584
keel at _D :
fit. double
keel at D! : 0.0 0.
All measurements in millimeters.
1960. Globotruncana marei Banner and Blow, Contr. Cushman
Found. Foram. Res., vol. 11, pt. 1, p. 8, (=G. eretacea Cush-
man, 1938).
1960. Globotruncana (Globotruncana) rosetta (Carsey), Pessagno,
Micropaleont., vol. 6, No. 1, p. 100, pl. 3, figs. 4-7; pl. 5, figs.
(HO
1962. Globotruncana (Globotruncana) rosetta (Carsey) , Pessagno, Mi-
cropaleont., vol. 8, No. 3, p. 362, pl. 4, figs. 6-8.
1962. Globotruncana (Globotruncana) rosetta (Carsey), Berggren,
Stockholm Contr. Geol., vol. 9, No. 1, p. 56, pl. 10, figs. la-e.
1962. Not Globotruncana rosetta (Carsey) , Barr, Paleontology, vol. 4,
pt. 4, pp. 575, 576, pl. 70, figs. da-c.
1963. Globotruncana (Globotruncana) rosetta rosetta (Carsey), Van
Hinte (part), Jahrb. Geol. Bund., Sond. 8, pp. 89-91, pl. 9, figs.
3a-c; not figs. la-c; 2a-c; not pl. 10, figs. la-c.
1964. Globotruncana rosetta (Carsey) , Olsson, Micropaleont., vol. 10,
No. 2, pp. 168, 169, pl. 4, figs. ba-c, 7a-c.
1964. Globotruncana marei Banner and Blow, Olsson, Micropaleont.,
vol. 10, No. 2, pp. 167, 168, pl. 4, figs. 8a-c; not 10a-c.
1964. Not Globotruncana rosetta (Carsey), Martin, Jahrb. Geol. Bund.
Sond. 9, p. 83, pl. 10, figs. 5a-c. ;
Description.—Test trochospiral, planoconvex (mean
T’X/TX value for 12 measured specimens=1.85), peri-
phery lobulate, acutely angled, truncated by narrow double
keel which frequently merges to form a single keel at some
point in last whorl; double keel becoming progressively
narrower from nepionic stage of development to ephebic or
gerontic stage of development. Chambers arranged in two
and one-half to three whorls; increasing in size at a rather
constant rate; five to six chambers in last whorl which are
crescent-shaped spirally and subrectangular umbilically. Su-
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 353
tures curved, raised, beaded spirally; straight to slightly
curved, beaded umbilically. Sectioned specimens usually
showing a well-developed double-keeled G. linneiana (d’Or-
bigny) stage of development. Umbilicus deep, moderately
wide, covered by a spiral system of tegilla with intralaminal
and infralaminal accessory apertures. Primary aperture in-
teriomarginal, umbilical in position. Outer wall radial hya-
line perforate except for keel which is both radial hyaline,
imperforate and ultragranular hyaline imperforate (variety
of type 2; Text-figure 40) ; single keel when present radial
hyaline, imperforate. Tegilla and septal walls microgranular
hyaline, perforate. |
Remarks.—Bronnimann and Brown (1956) examined
the holotype of Globotruncana rosetta (Carsey) in the col-
lections of the University of Texas. They noted that the
holotype possessed a narrow double keel on the early cham-
bers of the last whorl which merged to form a single keel
on the final chambers. Plummer (1951) failed to indicate
this double keel in her drawing’s of Carsey’s holotype. The
writer collected and examined a great deal of topotypic
material from the “Upper Taylor marl” in ‘Travis County,
Texas (TYPE 6A-C; see Appendix).
Globotruncana rosetta (Carsey) is most easily con-
fused with Globotruncana ventricosa White and Globo-
truncana aegyptiaca Nakkady. It differs from G. ventricosa
White (1) by having a more sharply angled periphery; (2)
by having a much narrower double keel that merges to form
a single keel in ephebic or gerontic specimens (compare
sum of keel heights of G. rosetta and G. ventricosa in Text-
figures 54, 60); (3) by being less convex umbilically (mean
T’X/TX value for 12 specimens of G. rosetta=1.85; mean
T’X/TX value for 13 specimens of G. ventricosa=2.65) ;
and (4) by lacking heavily beaded sutures and markedly
petaloid (G. linneiana-shaped) chambers spirally.
G. rosetta and G. ventricosa are closely related phylo-
genetically. Both species share well-developed G. linneiana-
type nepionic stages with wide double keels. However, the
double keel of G. rosetta narrows much more rapidly be-
tween the nepionic and ephebic stages of development.
G. rosetta (Carsey) is often nearly homeomorphic
for G. aegyptiaca Nakkady. It differs from G. aegyptiaca (1)
by possessing a somewhat smaller umbilicus; (2) by being
more convex umbilically; (3) by being nonrugose both
spirally and umbilically; and (4) by possessing a promi-
nent double-keeled G. linneiana nepionic stage rather than
a single-keeled nepionic stage. The fourth difference cited
above is regarded as the most definitive way of differenti-
ating these two species. Thin-sectioned specimens of both
species are figured herein.
G. rosetta (Carsey) has been confused by Bandy
(1951), Subbotina (1953), Hamilton (1953), Barr (1962),
and various other workers with G. elevata (Brotzen) .
Part of this confusion was undoubtedly due to Plummer’s
(1931) failure to illustrate the narrow double keel pres-
ent on the early chambers of Carsey’s holotype [see
remarks on G, elevata (Brotzen) herein].
The writer regards Globotruncana cretacea Cushman
(= Globotruncana marei Banner and Blow) as a small,
immature form of Globotruncana rosetta (Carsey) . Cush-
man’s holotype of G. cretacea Cushman has been re-
illustrated herein (PI. 73, figs. 5-8). Illustrations of
the same specimen by Cushman (1946, pl. 62, figs. 7a-c)
and by Olsson (1964, pl. 4, figs. 8a-c) do not show
the proper inflation of chambers on the umbilical side
of the test. Approximate measurements of the T’X/TX
values of the holotype of G. cretacea (refigured herein)
indicate that T’X/TX = 1.2. Hence, G. cretacea is rela-
tively planoconvex rather than biconvex as illustrated by
Cushman (1944) and Olsson (1964). The absence of a
single keel in the final whorl of G. cretacea is not regarded
as an important criterion for separating this species from
G. rosetta as smaller, immature specimens of G. rosetta
commonly possess a narrow double keel throughout their
last whorl. Thus, G. cretacea is treated a a junior synonym
of G. rosetta.
The writer examined the holotype of G. arca caribica
Gandolfi (No. 20854) at the Paleontological Research
Institution, Ithaca, New York, and considers this form
to be a junior synonym of G. rosetta (Carsey) .
Range.—G. fornicata—stuartiformis assemblage zone,
A. blowi subzone (D. multicostata zonule) to R. subcir-
cumnodifer subzone (R. subpennyi zonule); possibly
higher.
Occurrence.—In the course of this study, G. rosetta
has been observed in the Early Campanian portion of the
San Felipe in the type area of this unit near the village
of San Felipe west of Tampico and at Peregrina Canyon
northwest of Ciudad Victoria (Text-figures 1, 2). It like-
wise has been observed in the Campanian and Early Maes-
trichtian portions of the Méndez shale throughout the
area of study (Text-figures I, 2). It also occurs in Late
Campanian and Early Maestrichtian portions of Papagallos
shale north of Mamulique pass on the Mexico, D.F.—
Nuevo Laredo Highway (Rt. 85).
In Texas G. rosetta occurs throughout the Taylor
formation: in the “Lower Taylor marl” member of ‘Travis
and McLennan Counties; in the Pecan Gap chalk member
of McLennan County; and in the “Upper Taylor marl”
55 PALAEONTOGRAPHICA AMERICANA (V, 37)
member of Travis and Limestone Counties. It likewise
occurs in the Early Maestrichtian portion of the Upson
clay in Maverick County and in the Neylandville marl
of Navarro County.
In southwestern Arkansas G.
Late Campanian Ozan formation and Annona chalk and
in the Early Maestrichtian Marlbrook marl and Saratoga
chalk.
Olsson (1964) recently recorded this species from the
Mt. Laurel-Navesink formation of Delaware and from
the Marshalltown and Mt. Laurel formations of New
Jersey.
In the West Indies it was noted by Bronnimann and
Rigassi (1963) from the Via Blanca beds of Cuba under
the name of G. marei Banner and Blow. It has been re-
corded by Ayala (1959) from Late Campanian and Early
Maestrichtian strata of Haiti, and by Pessagno (1960,
1962) from the Campanian and Early Maestrichtian por-
tions of the Parguera limestone and Rio Yauco formation
of Puerto Rico. The occurrence in the Cariblanco forma-
tion cited by Pessagno (1962, p. 362; not Chart 4) was an
error. Elsewhere in the Western Hemisphere, G. rosetta
is known from the Colon formation of Columbia.
Berggren (1962, p. 60) noted G. rosetta from the Maes-
trichtian of Denmark.
rosetta occurs in the
Globotruncana spinea Kikoine
1947. Globotruncana spinea Kikoine, Soc. Géol. France, C. R. Somm.,
Nos. 1-2, p. 21, tfs., p. 21.
1957. Globotruncana (Globotruncana) spinea Kikoine, Edgell, Micro-
paleont., vol. 3, No. 2, p. 115, pl. 2, figs. 1-3.
Remarks.—G. spinea is the only double-keeled species
of Globotruncana s.s. possessing tubulospines. Its crescent-
shaped chambers spirally, subrectangular chambers umbili-
cally, parallel sides, and moderately wide double keel indi-
cate a close kinship with G. lapparenti s.s. Brotzen
(emended herein) .
Kikoine (1947, p. 21)
evolved from G. arca Cushman and in turn gave rise to
G. calcarata Cushman. As noted above and in Text-figure
35, the writer favors the idea of its evolution from G.
lapparenti s.s. It is in no way closely related to G. calcarata
Cushman. G. calcarata possesses a single keel throughout
suggested that this species
all but its embryonic (globigeriniform) stage of develop-
ment.
Range.—Uncertain. G. fornicata—stuartiformis assem-
blage zone, A. blowi subzone (D. multicostata zonule)
insofar as known.
Occurrence. — G. spinea is rare in the Upper Creta-
ceous deposits of the Western Hemisphere. To date, it has
only been observed in the uppermost part (Early Cam-
panian) part of the San Felipe formation in the Tampico
area,
Elsewhere it is known from the Cretaceous of France
and Australia.
Globotruncana stephensoni Pessagno, n. sp.
Plate 69, figures 1-7; Plate 96, figures 5, 6
1931. Globotruncana arca (Cushman), Plummer (part), Univ. Texas
Bull. 3101, pp. 195-198, pl. 13, figs. 7a-c; not figs. 8, 9, 11.
1957. Globotruncana (Globotruncana) arca (Cushman), Edgell (part) ,
Micropaleont., vol. 3, No. 2, pp. 110, 111; pl. 1, figs. 10-12; not
pl. 3, figs. 1-3, 13-15.
1962. Globotruncana conica White, Pessagno, Micropaleont., vol. 8,
No. 3, p. 302, text-fig. 4, pl. 4, figs. 13, 14.
1963. Globotruncana (Globotruncana) rosetta rosetta (Carsey) , Van
Hinte (part), Jahrb. Geol. Bund., Sond. 8, pp. 89-91, pl. 9, figs.
la-c; 2a-c; not pl. 9, figs. 3a-c; pl. 10, figs. la-c.
Description.—Test trochospiral, spiroconvex (mean
T’X/TX value for five measured specimens — 0.388) ;
periphery sharply angled with narrow double keel merg-
ing to form a single keel in last whorl; rare specimens
single-keeled entirely in final whorl, but when sectioned
showing double keel in preceding whorl; double keel when
present, strongly reflected umbilically. Test having about
three whorls of chambers which slowly expand in size;
six to seven chambers in last whorl. Chambers spirally, typi-
cally trapezoidal to subtrapezoidal, but often petaloid,
crescent-shaped, or subtriangular, separated by straight to
slightly curved, raised, often beaded sutures. Chambers
individually smoothed surfaced, containing few if any
deep and wide; surrounded by
umbilical shoulder which may or may not be beaded;
umbilicus covered by spiral system of tegilla having intra-
laminal and infralaminal accessory apertures. Primary
rugosities. Umbilicus
aperture interiomarginal, umbilical in position. Outer wal!
radial hyaline, perforate except for keels. Keels
single predominantly radial hyaline, imperforate;
double in part radial hyaline, imperforate, and
when
when
ultra-
granular hyaline, imperforate (‘variety of type 1; Text-
figure 40): umbilical rim of double keel weak, entirely
ultragranular hyaline, imperforate; spiral rim with radial
hyaline, imperforate base which is strengthened by accre-
tion of ultragranular hyaline outer portion. Septal walls
and tegilla microgranular hyaline, finely perforate.
Remarks.—G. stephensoni Pessagno, n. sp.
related phylogenetically to G. arca (Cushman). Ephebic
individuals of G. stephensoni, n. sp. differ from those of
G. arca having approximately the same diameter by (1)
is closely
yossessing angled peripheries; (2) narrow double keels
] $ s
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 355
which merge to form a single keel in the last whorl; and
(3) by usually having more trapezoidally shaped chambers.
Both species possess double keels which are strongly re-
flected umbilically and have similar structure (TYPE 1;
Text-figure 40) .
G. stephensoni, n. sp. may be perfectly homeomorphic
externally for either high-spired forms of G. stuarti (de
Lapparent) s.s. or for G. conica White and can only be
separated in thin-section from these latter species. Most
Campanian and Early Maestrichtian occurrences of G.
conica and G. stuartt (de Lapparent) s.s. most likely rep-
resent occurrences of G. stephensoni, n. sp. For example,
Pessagno (1960, p. 91, chart 2; 1962, p. 355, chart 4) noted
G. conica in Puerto Rican strata of Late Campanian and
Early Maestrichtian age. The sectioned specimen figured
as G. conica White by Pessagno (1962, text-figure 4, p. 362)
resembled G. conica externally. It possessed subtrapezoidal
chambers spirally and showed a spiroconvex test. However,
it also showed a narrow double keel in the posterior por-
tion of the last whorl and in the preceding whorl.
G. stephensoni Pessagno, n. sp. is named in honor of
the late L. W. Stephenson in recognition of his great
contributions to the study of the Cretaceous stratigraphy
of the Atlantic and Gulf Coastal Plains.
Form analysis data for sectioned specimens of G.
stephensoni, n. sp. are included in Text-figure 55.
Type locality—TX 291-B. Taylor formation (“Upper
‘Taylor marl” member) . Buff calcareous mudstone breaking
with concoidal fracture; collected from ditch crossing
State Route 73; 2.4 miles east of intersection of Route 73
with Farm Road 737 in town of Prairie Hill, Limestone
County, Texas.
Deposition of types —The holotype and figured pava-
types of G. stephensoni will be deposited in the collections
of the U.S. National Museum, Washington, D.C. Unfeg-
ured paratypes will be deposited at the Paleontological
Research Institution, Ithaca, New York.
Range.—G. fornicata—stuartiformis Assemblage zone,
A, blowi subzone (D. multicostata zonule) to R. subecir-
cumnodifer subzone (R. subpennyi zonule) in so far as
known.
Occurrence.—In Mexico this species occurs in the
Early Campanian to Early Maestrichtian portions of the
Méndez shale and in the Early Campanian portion of the
San Felipe formation.
In ‘Texas it occurs in the Pecan Gap chalk of McLen-
nan County; the “Upper Taylor marl” of Travis and Lime-
stone Counties; and in the Upson clay of Maverick County.
In southwestern Arkansas G. stephensoni, n. sp. occurs
TEXT-FIGURE 55:
Globotruncana
TX 291-A
PE 793
TX 291-A
PE 800
TX 291-A
TXT
Ht. double
keel at D
Ht. double
keel at Di"
Double kee
pee ean
All measurements in millimeters.
(=)
Pe
* + = presence of double keeled early stage.
356 PALAEONTOGRAPHICA AMERICANA (V, 37)
in the Ozan formation and Annona chalk of Sevier County
and in the Saratoga chalk of Hempstead County.
Van Hinte (1963, part) figured G. stephensoni as G.
rosetta (Carsey) from the Upper Cretaceous of Austria.
Globotruncana stuarti (de Lapparent)
Plate 81, figures 1-6; Plate 93, figures 9-11; Plate 94, figure 7
1918. Rosalina stuarti de Lapparent, Serv. Carte Géol. Mém., Paris,
France, p. 11, pl. 1, ?figs. 5, 6; 73 tf. 4 (p- Wp es 5a, b, ze (p-
13). (Lectotype designated herein; tf. 4 (p. 12), lower 3 fig-
ures) . : é
1936. Not Globotruncana stuarti (de Lapparent) , Renz, Eclogae Geol.
Helv., vol. 29, No. 1, pl. 6, figs. 35-41; pl. 8, fig. 4, figs. 37-38—
G. elevata (Brotzen); figs. 39—?41=G. stwartiformis Dalbiez) a
1941. Not Globotruncana linnei stuarti Vogler, Palaeontographica,
Suppl. Bd. 4, Abt. 4, p. 289, pl. 24, figs. 8-13. cA
1941. Not Globotruncana stuarti (de Lapparent) , Vogler, Palaeonto-
graphica, Suppl. Bd. 4, Abt. 4, p. 289, pl. 23, figs. 40, 41 (=G.
elevata (Brotzen) . J
1945. Globotruncana stuarti (de Lapparent) , Bolli (part), Eclogae
Geol. Helv., vol. 37, No. 2, p. 236, pl. 19, fig. 18; not text-fig. 1:
fig. 27; 2 28. : :
1950. Globotruncana (Globotruncana) stuarti (de Lapparent), Reichel
(part) , Eclogae Geol. Helv., vol. 42, No. 2, pp. 613-615, pl. 16,
fig. 10; pl. 17, fig. 10; not text-fig. 7a. y
1950. 2? Globotruncana arca (Cushman) var. esnehensis Nakkady, Jour.
Paleont., vol. 24, No. 6, p. 690, pl. 90, figs. 23, 24.
1951. Not Globotruncana stuarti (de Lapparent) , Bolli, Jour. Paleont.,
vol. 25, No. 2, p. 196, pl. 34, figs. 10-12. (=Globotruncana
stuartiformis Dalbiez).
1951. Not Globotruncana stuarti (de Lapparent) Tiley, Lausanne
Univ., Mus. Géol., Lab. Géol., Min., Géophys., Bull. No. 103,
pp. 34-41, text-figs. 7a-c; 8a-d_ (figs. Ja-c—G. elevata Brotzen;
figs. 8a-d=G. stuartiformis Dalbiez) .
1952. Globotruncana falsostuarti Sigal, 19th Congr. Géol. Internat.,
Monogr. Rég., Alger, ser. 1, No. 26, p. 43, text-fig. 46.
1953. Not Globotruncana stuarti (de Lapparent), Subbotina, Trudy,
Vses. Neft. Nauckno—Issled. Geol. Razved. Instit., n. ser., No.
76, p. 201, pl. 15, figs. 3a-5e (Figs. 3a-c; 5a-c=G. elevata Brotvzen;
figs. 4da-c;=transitional form between G.. stuartiformis and
G. elevata with approximate T’X/TX value of 1.10).
1955. Globotruncana (Globotruncana) stuarti (de Lapparent), Dal-
biez, Micropaleont., vol. 1, No. 2, p. 170 text-figs. 4a-c.
1955. Not Globotruncana stuarti stuarti (de Lapparent) Gandolfi,
Bull. Amer. Paleont., vol. 36, No. 155, p. 64, pl. 5, figs. 6a-c.
1956. Not Globotruncana stuarti (de Lapparent), Said and Kenawy,
Micropaleont., vol. 2, No. 2, p. 151, pl. 5, figs. 22a-c [=transi-
tional form between G. conica White and G. stuarti (de Lap-
parent) with an approximate T’X/TX value of 0.46].
1956. Not Marginotruncana stuarti (de Lapparent), Hofker, Neues
Jahrb. Geol. Paleont., Abh. 103, pp. 332, 333; text-fig. 23.
1957. Globotruncana stuarti (de Lapparent), Sacal and Debourle
(part) , Soc. Geol. France, n. sér., Mem. No. 78, p. 60, pl. 26,
fig. 5; not pl. 27, figs. 15, 19.
1961. Globotruncana rosetta (Carsey), Said and Kerdany, Micropal-
eont., vol. 7, No. 3, p. 331, pl. 2, figs. 13a-c.
1961. Globotruncana sp. ind. Corminboeuf, Eclogae Geol. Helv., vol.
54, No. I, p. 117, pl. 2, figs. 2a-c.
1962. Globotruncana (Globotruncana) stuarti (de Lapparent), Berg-
gren, Stockholm Contr. Geol., vol. 9, No. 1, pp. 60-64, pl. 10,
figs. 2a-c.
1962. Globotruncana (Globotruncana) stuarti stuarti (de Lapparent) ,
Pessagno, Micropaleont., vol. 8, No. 3, pl. 2, figs. 1-3 (no
pagination) .
1964. Not Globotruncana stuarti stuarti (de Lapparent) , Olsson, Mi-
cropaleont., vol. 10, No. 2, pp. 58-60, pl. 8, figs. 9a-c (=G.
stuartiformis Dalbiez; nearly transitional to G. elevata Brotzen) .
Description.—Test trochospiral, spiroconvex, occasion-
ally biconvex (mean T’X/TX value for 18 measured speci-
mens — 0.79; cf. Text-figures 37, 58; Chart 2). Peripheral
outline almost circular; axially acutely angled, possessing
well-developed single keel; sectioned specimens showing
single keel in all but embryonic (globigeriniform) stage
of development. Chambers spirally, trapezoidal to crescent-
shaped; typically, trapezoidal; separated by straight to
slightly curved, raised, beaded sutures; chambers umbili-
cally subrectangular; separated by straight to slightly curved
raised, beaded sutures. Umbilicus small relative to test
diameter, surrounded by prominent, beaded umbilical
shoulder; covered by spiral system of tegilla displaying in-
tralaminal and infralaminal accessory apertures. Primary
aperture interiomarginal, umbilical in position. Outer wall
radial hyaline, perforate except for beads and single keel.
Beads ultragranular hyaline, imperforate; keel radial hya-
line, imperforate, Early whorls of test usually showing wide
radial hyaline, imperforate bands situated umbilically
beneath keel [e.g., figs. 5a-b, p. 13, De Lapparent 1918;
Pl. 93, figs. 9-11 herein].
Remarks.—G, stuarti s.s. (de Lapparent) is closely re-
lated to G. conica White and undoubtedly gave rise to
the latter species (Text-figure 34). These two species are
separated principally on the basis of their spiral convexity.
Criteria used herein for their separation have been discussed
under G. conica White (see also Text-figures 36, 37, 58,
Table 2).
G. stuarti s.s. (de Lapparent) is also closely related
phylogenetically to G. stuartiformis Dalbiez. Many micro-
spheric specimens of G. stuarti s.s. show a G. stuartiformis
stage with subtriangularly shaped chambers in their earlier
whorls. G. stuarti s.s. (de Lapparent) can be usually differ-
entiated from G,. stuartiformis Dalbiez externally by pos-
sessing trapezoidally shaped chambers in its final whorl.
Its chambers may be entirely trapezoidal or may be in
part crescent-shaped or sometimes subtriangular. The pro-
portion of trapezoidal chambers is variable. In thin section,
G. stuarti s.s. differs from G, stwartiformis (1) by possess-
ing wide radial hyaline imperforate bands in earlier whorls
immediately beneath the keel umbilically and (2) by usu-
ally possessing a smaller umbilical diameter relative to its
test diameter (cf. Text-figures 36, 58, Table 2). The
T’X/TX values of both species are relatively similar (mean
T’X/TX = 0.79 for 18 measured specimens of G, stuart? s.s.;
mean ‘T’X/TX value — 0.92 for 26 measured specimens of
G. stuartiformis). The wide radial hyaline imperforate
bands noted above seem to represent the reconstitution of
the perforate part of the test probably at the adult stage of
development. Occasional specimens may have completely
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 357
radial hyaline imperforate early whorls. This same charac-
teristic is shared by G. conica White.
G. stuarti (de Lapparent) is the earliest name ap-
plied to single-keeled Campanian and Maestrichtian species
of Globotruncana. Most earlier workers simply included
all single-keeled species, herein assignable to the G. stuarti
lineage group, under G. stuarti (de Lapparent). For
example, forms herein assignable to G. elevata (Brotzen)
and G. stuartiformis (Dalbiez) were frequently assigned
by previous workers to G. stuarti (de Lapparent). The
modern tendency, however, is to treat G. elevata, G. stuarti-
formis and G. stuarti s.s. as separate species.
It is likely that both G. esnehensis Nakkady and G.
falsostuarti Sigal are junior synonyms of G. stuarti s.s.
Comparative specimens of G. falsostuarti given to the writer
by Dr. J. Sigal appear either to be assignable to G. stuart:
s.s. or to G. conica. The holotype of G. falsostuarti is rela-
tively biconvex and falls well within the range of G. stwarti
s.s. In terms of its T’X/TX value. Comparative specmens
of G. esnehensis given to the writer by Dr. Z. R. El-Naggar
from the Maestrichtian of Egypt are similar to G. stwarti
in terms of their T’X/TX values. However, their chambers
are somewhat more petaloid spirally than typical for the
latter species.
The phylogenetic relationships of the G. stuart: lineage
group are indicated in Text-figure 34.
Text-figure 58 and Table 2 give form analysis data
for G. stuarti s.s. Text-figure 37 is a scatter plot of the
T’X/TX values and D-D’ values of G. stuarti s.s. and G.
conica,
Range.—G. contusa—stuartiformis assemblage zone, G.
gansseri subzone (uppermost part) to A. mayaroensis sub-
zone (uppermost part). This is one of the most important
zone fossils in the Upper Cretaceous of the Western Hemis-
phere.
Occurrence.—In the present study G. stuarti s.s. has
been found at a number of localities in the Méndez shale
of Mexico in strata assignable to the A. mayaroensis sub-
zone. It is particularly abundant, for example, at the type
locality of G. conica White. In northern Mexico, north of
Monterrey and Mamulique Pass along the Mexico, D.F.—
Nuevo Laredo Highway, G. stuart occurs in the Papagallos
shale strata which are of Late Middle Maestrichtian age
(uppermost part of G. gansseri subzone) (MX 174, see
Appendix) .
In Texas, G. stwarti s.s. has been observed only at
localities TX 267A-C, 268-270 (see Appendix) in the
upper part of the Kemp clay in Falls County from 20 feet
below to immediately below the Midway (Kincaid) —Kemp
clay contact. Elsewhere in the Western Hemisphere, the
writer has seen G. stuarti s.s. in samples from the Late
Maestrichtian part (A. mayaroensis subzone) of the Guay-
aguayare formation of Trinidad.
G. stuarti s.s. is known from the Maestrichtian of
France, Switzerland, Denmark, Egypt, Tunisia, and Algeria.
Berggren (personal communication) informed the writer
that G. stuart? s.s. occurs in strata assignable to the upper
part of G. gansseri subzone and to the 4. mayaroensis sub-
zone in Libya.
Globotruncana stuartiformis Dalbiez
Plate 80, figures 3-6 (G. stuartiformis transitional to G. elevata
Brotzen); Plate 92, figures 1-3; Plate 93, figures 6, 7. Text-
figure 44; figure 17 only
1936. Globotruncana stuarti (de Lapparent), Renz, Eclogae Geol.
Helv., vol. 29, No. 1, pp. 35, 36, pl. 6; figs. 39-41; not 37, 38; not
pl. 8, fig. 6.
1945. Not Globotruncana stuarti (de Lapparent) , Bolli, Eclogae Geol.
Helv., vol. 37, No. 2, p. 236, text-fig. 1, figs. 27, 28; pl. 19, fig. 18.
1950. Globotruncana stuarti (de Lapparent) , Reichel (part), Eclogae
Geol. Helv., vol. 42, No. 2, pp. 613-615, text-fig. 7a; not pl. 16,
fig. 10; not pl. 17, fig. 10.
1951. Globotruncana stuarti (de Lapparent), Bolli, Jour. Paleont., vol.
25, No. 2, p. 196; pl. 34, figs. 10-12.
1951. Globotruncana stuarti (de Lapparent), Tilev (part) , Lausanne
Univ., Mus. Géol., Lab. Géol., Min., Géophys., Bull., No. 103,
pp. 34-41, text-figs. 8a-d; not 7a-c.
1953. Globotruncana stuarti (de Lapparent) , Subbotina (part) , Trudy
Vses. Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76,
p. 201, pl. 15, figs. 4a-c; not 3a-c, 5a-c.
1953. Globotruncana stuarti (de Lapparent), Hamilton, Jour. Pal-
eont., vol. 27, No 2, p 233, pl. 29, figs. 11-13.
1955. Globotruncana (Globotruncana) elevata stuartiformis Dalbiez,
Micropaleont., vol. 1, No. 2, p. 169, text-figs. 10a-c.
1955. Globotruncana stuarti stuarti (de Lapparent), Gandolfi, Bull.,
Amer. Paleont., vol. 36, No. 155, p. 64, pl. 5, figs. 6a-c.
1955. Globotruncana stuarti parva Gandolfi, Bull. Amer. Paleont., vol.
36, No. 155, p. 65, pl. 5, figs. 7a-c.
1959. Globotruncana stuarti (de Lapparent), Olvera, Univ. Nac. Aut.
México, Facultad Ciencias, Dept. Biol., Tesis Prof., pp. 58-60,
PIS bes ad-0-
1959. Globotruncana (Globotruncana) elevata stuartiformis Dalbiez,
Banner and Blow, Paleontology, vol. 2, pt. I, p. 24, pl. 2, figs.
2a-c.
1962. Globotruncana (Globotruncana) stuartiformis Dalbiez, Pessagno,
Micropaleont., vol. 8, No. 3, p. 362, pl. 2, figs. 4-6.
1962. Globotruncana (Globotruncana) stuarti subspinosa Pessagno,
Micropaleont., vol. 8, No. 3, p. 362, pl. 2, figs. 7-9.
1962. Globotruncana elevata stuartiformis Dalbiez, Herm, Bayer.
Akad. Wiss. Math.—Nat. KI, Abh., n. ser., No. 104, p. 77, pl. 8,
figs. 2.
1963. Globotruncana (Globotruncana) elevata subspinosa Pessagno,
Van Hinte, Jahrb. Geol. Bund., Sond. 8, p. 71, pl. 3, figs. 3a-c;
pl. 4, figs. la-c.
1964. Globotruncana stuarti stuarti (de Lapparent), Olsson, Micro-
paleont., vol. 10, No. 3, pp. 169, 170, pl. 4, figs. 9a-c.
1964. Not Globotruncana stuarti stuartiformis Dalbiez, Olsson, Micro-
paleont., vol. 10, No. 3, pp. 169, 170, pl. 4, figs. 9a-c.
1964. Globotruncana rosetta (Carsey), Martin, Jahrb. Geol. Bund.
Sond., 9, p. 83, pl. 10, figs. 5a-c.
Description.—Test trochospiral, lenticular, nearly bi-
convex (mean T’X/TX value for 26 measured specimens =
0.92) with sharply angled, single-keeled periphery. Single
358 PALAEONTOGRAPHICA AMERICANA (V, 37)
keel present in all but embryonic (globigeriniform) stage.
Test consisting of two and one-half whorls of chambers;
usually six or seven chambers in final whorl. Chambers
spirally subtriangular to crescent-shaped; typically sub-
triangular; separated by raised, beaded, straight to slightly
curved sutures (Text-figure 44, fig. 17). Chambers um-
bilically subrectangular to subtriangular, separated by
beaded, straight to curved sutures. Individual chamber sur-
faces both spirally and umbilically relatively flat and un-
ornamented. Umbilicus large, deep, bordered by umbilical
shoulder which may be beaded; covered by spiral system
of tegilla displaying intralaminal and infralaminal acces-
sory apertures. Primary aperture interiomarginal, umbilical
in position. Outer wall except for single keel and beads
radial hyaline, perforate. Keel radial hyaline, imperforate;
beads ultragranular hyaline, imperforate. Septal walls and
tegilla microgranular hyaline, finely perforate.
Remarks.—G. stuartiformis Dalbiez is the basic species
of the single-keeled G. stuarti lineage group (Text-figure
34). It gave rise through transitional forms to both G.
elevata (Brotzen) and to G. stwarti s.s. (de Lapparent) .
G. stuartiformis can be differentiated from G. elevata:
(1) by the nearly biconvex nature of its test (mean T’X/
TX value for 26 measured specimens of G. stuartiformis =
0.92; mean T’X/TX value for 35 measured specimens of
G. elevata = 2.31; cf. Text-figures 42, 43, 59; Table 2) ;
(2) by usually having subtriangular or crescent-shaped
chambers spirally as opposed to petaloid or crescent-shaped
chambers; and (3) by being more finely perforate. As
noted in the discussion of G. elevata, the writer regards the
first of these criteria as being the most important in the
separation of these species. The basis for the separation of
these species using form analysis data is cited under G. ele-
vata and is summarized in ‘Text-figure 45 and Table 2.
Specimens having T’X/TX values greater than 1.07 and
less than 1.25 are considered transitional herein.
The basis for separating G. stwartiformis Dalbiez from
G. stuarti s.s. (de Lapparent) has been discussed under the
latter species. Previous to Dalbiez’s erection of G. stwarti-
formis in 1955, numerous workers included this form under
G. stuarti s.s. This is well documented in the above
synonomy.
The writer has examined the holotype of G. stuarti
(No, 20855) at the Paleontological Re-
search Institution, Ithaca, New York, and considers it to
be a variant of G. stuartiformis Dalbiez.
parva Gandolfi
The specimen figured by Pessagno (1962) as G. stuarti
subspinosa Pessagno has a measured T’X/TX value of
1.0 and is treated herein as G. stuartiformis. The holotype
of G. subspinosa Pessagno and the paratypes of G. swbspi-
nosa Pessagno show higher T’X/TX values which fall
within the lower limits of G. elevata Brotzen. In this
monograph, G. subpsinosa is regarded as a variant of
G. elevata.
The two specimens figured by Olsson (1964) as G.
stuarti stuartiformis both have high T’X/TX values and
fall well within the limits of G. elevata established herein.
On the other hand, the biconvex specimen (approximate
T’X/TX value = 1.0) figured by Olsson (1964) as G.
stuarti stuarti (de Lapparent) lacks trapezoidal chambers
spirally; has a large umbilicus; and possesses occasional sub-
triangular chambers. ‘The writer feels that this specimen is
referable to G. stuartiformis Dalbiez.
‘The specimen figured by Martin (1964) as G. rosetta
(Carsey) lacks a double keel and is clearly a member of the
single-keeled G. stwarti lineage group. Although it has cres-
cent-shaped chambers and lacks subtriangular chambers
spirally, it has an approximate T’X/TX value of 1.0
Thus, herein it is regarded as a variant of G. stuartiformis
Dalbiez.
As noted previously, G. stwartiformis Dalbiez forms the
basic stock from which other species of the G. stuart: line-
age group evolved either directly or indirectly. The phylo-
genetic relationships indicated in ‘Text-figure 34 have been
well-documented by the examination of specimens from
numerous samples from the West Indies, Mexico, Texas,
Arkansas, and elsewhere in the Western Hemisphere. G.
elevata evolved directly from G. stwartiformis during Late
Campanian times (G. elevata subzone) through dorsal flat-
tening and the acquisition of predominantly crescent-shaped
or petaloid chambers in the last whorl. Most specimens of
G. elevata show a suppressed G. stuartiformis stage of de-
velopment in earlier whorls both in thin-section and ex-
ternally on the spiral sides of their tests. The specimen
figured in Plate 80, figs. 3-6 herein, is perfectly transitional
between these two species.
G. elevata in turn gave rise to G. calcarata Cushman
probably via a “G. subspinosa Pessagno’’-type variant. In
late Middle Maestrichtian times (upper part of G. gansseri
subzone) , G. stuartiformis gave rise to G. stuarti s.s. through
a slight increase in spiral convexity and a change in cham-
ber shape from triangular or crescent-shaped to subtrape-
zoidal, A G. stuartiformis stage with triangularly shaped
chambers is frequently reflected in the early whorls of G.
stuarti s.s. G. stuarti s.s. in turn gave rise to G. conica White
through a great increase in the spiral convexity of the test
and the acquisition of more trapezoidal chambers.
Range.—G. fornicata—stuartiformis assemblage zone, A.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 5359
blowi subzone (D. multicostata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone. ‘This
is one of the most important zone fossils in the Upper
Cretaceous. In the Western Hemisphere, G. stuartiformis
universally makes its first appearance in the earliest Cam-
panian deposits. It is probable that Collignon’s (1959,
p- 52, Table 5) reference to G. elevata in the Anapachy-
discus wittekindi zone (ammonite) of the earliest Cam-
panian of Madagascar refers to G. elevata s.l. or G. elevata
stuartiformis Dalbiez in the sense of French workers. Irre-
gardless of the precise specific identity of Collignon’s re-
corded specimens, it is important to note that a member
of the single-keeled G. stuarti lineage group has been
recorded in the earliest Campanian deposits of Madagas-
car and that no members of this lineage group have been
recorded by Collignon (ibid., table 4) from the Santonian.
Occurrence.—In the present study G. stwartiformis was
observed in Mexico in the upper (Early Campanian) por-
tion of the San Felipe formation principally in the following
areas: (1) in the type area of this unit near the village of
San Felipe immediately west of the Sierra del Abra and
east of Ciudad Valles; (2) in the Sierra Madre Oriental
west of Tampico along the road (Rt. 80) between Antiguo
Morelos and Ciudad del Maiz; (3) immediately west of
where the México City, D.F.-Nuevo Laredo Highway (Rt.
85) crosses the southwest flank of the Sierra del Abra (MX
69, see Appendix) to the northwest of Antiguo Morelos;
and (4) at Peregrina Canyon northwest of Ciudad Victoria
(Text-figures 1,2). G. stuartiformis also occurs in the
Méndez shale in deposits ranging from Early Campanian
to Late Maestrichtian age in the Tampico area and the
Sierra Madre Oriental to the west (Text-figures 1-2) .
In Texas G. stwartiformis occurs in the reworked upper-
most part of the Austin chalk in Dallas County in deposits
which are of Early Campanian age (4. blow: subzone, P.
glabrata zonule). To date, it has not been observed any-
where in the type area of the Austin chalk at Austin.
However, Young (1963, pp. 17-24) on the basis of the am-
monite assemblage maintained that the upper portion of
the type Austin (Dessau, Burditt, “Big House” members) is
of Early Campanian age. His dating is largely based on
ammonites such as Delawarella delawarensis (Morton) ,
Delawarella campaniensis (Grossouvre) , and other species
which are characteristic of the Campanian of Europe and
Madagascar. A more detailed discussion of the age of the
type Austin chalk will be presented elsewhere. G. stwarti-
formis occurs throughout the Taylor formation in the
following members: (1) the “Lower Taylor marl” of Travis,
McLennan, and Dallas Counties; (2) the Wolfe City sand
of McLennan County; (3) the Pecan Gap chalk of Mc-
Lennan County; and (4) the “Upper Taylor marl” of Travis
and Limestone Counties. It likewise occurs in the Upson
Clay of Maverick County; the Corsicana marl of Travis
and Navarro Counties; and the Kemp clay of Falls County.
In southwestern Arkansas G. stwartiformis has been
observed in the lower portion of the Brownstown marl; in
the Ozan formation; in the Marlbrook marl; in the Sara-
toga chalk; and in the Arkadelphia marl.
Elsewhere in North America, this species was figured
by Olsson (1964) as G. stuart s.s. (de Lapparent) from
the Redbank formation of New Jersey and by Martin
(1964) as G. rosetta (Carsey) from the lower part of the
Uhalde formation (Panoche group) of Fresno County,
California. The writer has seen lately this species in thin-
sectioned Late Campanian and Early Maestrichtian lime-
stones from Panama.
In the West Indies G. stwartiformis has been observed
by the writer in samples from Cuba and Hispaniola. In
Puerto Rico it occurs in the Parguera limestone, Rio Yauco
formation, and in the upper part of the Cariblanco forma-
tion (cf. Pessagno 1960, 1962). In Trinidad G. stuartiformis
occurs in the upper part (Campanian) of the Naparima
Hill formation and throughout the Guayaguayare formation
(Maestrichtian) .
In Eurasia G. stuartiformis has been recorded under
various names from the Campanian and Maestrichtian de-
posits of France, Italy, Switzerland, Austria, and Russia.
In Africa it is known from the Campanian and Maestrich-
tion of Tunisia and from the Campanian of Tanganyika.
It is also known from the mid-Pacific guyot area.
Globotruncana trinidadensis Gandolfi
Plate 84, figures 4-12; Plate 90, figures 9-10;
Plate 96, figures 1, 2; Text-figure 57
1918. Not Rosalina linnei d’Orbigny “mutation caliciforme” de Lap-
parent, Mém. Carte Géol. France, p. 8, tf. 2, fig. j, pl. 1, fig. 2
(nomen nudum, also=G. contusa (Cushman) .
1941. Not Globotruncana linnei d’Orbigny caliciformis Vogler, Pal-
aeontographica, Suppl. Bd. 4, Abt. 4, p. 228, pl. 24, fig. 23 (=
G. contusa (Cushman).
1951. Globotruncana caliciformis (de Lapparent), Bolli, Jour. Pal-
eont., vol. 25, No. 2, pp. 195, 196, pl. 34, figs. 4-6.
1953. Globotruncana caliciformis (de Lapparent), Hamilton, Jour.
Paleont., vol. 27, No. 2, p. 232, pl. 29, figs. 6-8.
1955. Globotruncana caliciformis trinidadensis Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, p. 47, pl. 3, figs. 2a-c (holotype re-
illustrated in Text-figure 57 herein) .
1955. Globotruncana caliciformis sarmientoit Gandolfi, Bull. Amer.
Paleont., vol. 36, No. 155, pp. 47, 48, pl. 3, figs. 3a-c.
1955. Globotruncana caliciformis caliciformis (de Lapparent), Gan-
dolfi, Bull. Amer. Paleont., vol. 36, No. 155, pp. 46, 47, pl. 3,
figs. la-c.
1957. Globotruncana fornicata Plummer, Sacal and Debourle (part) ,
Soc. Géol. France, n. sér. Mém. No. 78, p. 61, pl. 28, fig. 8; not
figs. 65:75 4, Lb:
360 PALAEONTOGRAPHICA AMERICANA (V, 37)
Emendation.—Test trochospiral, spiroconvex (mean
T’X/TX value for 8 specimens = 0.44) , truncated by um-
bilically reflected double keel which may merge to form a
single keel; two and one-half to three whorls of chambers,
rapidly expanding in size; four to five chambers in final
whorl; final whorl 2.1 to 2.4>< size of preceding whorl.
Chambers in final whorl spirally with vaulted surfaces;
crescent-shaped tending to become petaloid; separated by
raised, heavily beaded, straight to curved sutures. Chambers
umbilically flat surfaced, subrectangular in shape, separated
by slightly depressed to flush, lightly beaded sutures.
Chambers in early whorls often globigeriniform in shape.
Chambers surfaces both spirally and umbilically often
slightly rugose. Umbilicus deep, surrounded by beaded to
nonbeaded umbilical shoulder; covered by spiral system
of tegilla with intralaminal and infralaminal accessory
TEXT-FIGURE 56:
trinidadensis
Globotruncana
Gandolfi
. 364] 0.39210. 364]0.406
0.168 |0. 238 j0.252 |o.205]0. 196] 0.196 o.238]0.182
Tie fram eran fp sofeeaba
ee ee
Wee oS hs.o° fs. g 5¢.0°]39.0°] 35.0" 42.0° [41.04
sor ea aoe eae ese (a ee
foe fabae neh efoberfertse
sie xo. fas. oe Se OF as OF
| x0 {0.140}. 140 Jo. 205 0.168]. 140l 0.154 0.168}0.168
Ts foo fen annac
fa ff fs fi fs oe
double
0.070 ]0.084 |o.070]0. 056] 0.056] 0.084]0.084] 0.070
kel at D
douB Leigh O70 0.056] 0.056]0.084] 0.056
ee at D
All measurements in millimeters (except angles).
-
TEXT-FIGURE 57:
Holotype of Globotruncang trinidadensis Gandolfi. X54
apertures. Primary aperture interiomarginal, umbilical in
position. Outer wall radial hyaline, perforate except for
keel, rugosities, and beads. Single keel in final whorl
radial hyaline, imperforate; double keel in final whorl
radial hyaline, imperforate and ultragranular hyaline, im-
perforate (‘‘variety” of type 2; Text-figure 40); double
keel in preceding whorl radial hyaline imperforate and
ultragranular hyaline imperforate with umbilical rim en-
tirely ultragranular hyaline imperforate (‘‘variety’” of
type 1, Text-figure 40). Beads and rugosities ultragranu-
lar hyaline perforate septal walls and tegilla microgranular
hyaline, finely perforate. Earlier whorls of test often
completely imperforate and consisting of radial hyaline
calcite.
Remarks.—Bolli (1951) and Gandolfi (1955) corre-
lated this form with Rosalina linnei d’Orbigny “mutation
calciforme” de Lapparent (1918, p. 8, tf. 2, fig. j; pl. 1, fig.
2). De Lapparent’s form is definitely assignable to G. con-
tusa (Cushman). Furthermore, as noted under G. contusa,
De Lapparent’s name is invalid (= a nomen nudum) be-
cause it is not in Latin and does not conform to the Code of
Zoological Nomenclature. As indicated by Ellis and Mes-
sina (Catalogue of Foraminifera), Vogler’s (1941) Latin-
ized name, G. linnei caliciformis, represents the first valid
use of this name.
The first valid name actually applied to the form
figured herein and by Bolli (1951, pp. 195,196, pl. 34, figs.
4-6) seems to be G. trinidadensis Gandolfi. The writer ex-
amined the holotypes of G. caliciformis trinidadensis Gan-
dolfi (No. 22840) and G. caliciformis sarmientot Gandolfi
GuLF CRETACEOUS FORAMINIFERA: PESSAGNO 561
TEXT-FIGURE 58:
7
de Lapparent
de Lapparent
fig.
PE 680 *«**
Globotruncana
Stwaritas sini.
23
i)
peer pert 5° 130.8° |38.0° 37.0
N
so)
°
°
All measurements in millimeters.
* Specimen of G. esnehensis Nakkady from El-Naggar.
** Specimen of G. falsostuarti Sigal from Sigal.
*kk Transitional to G. conica White
(No. 20841) at the Paleontological Research Institution,
Ithaca, New York. Both G. trinidadensis and G. sarmientot
represent slightly different variants of the same taxonomic
unit. As the holotype of G. trinidadensis is more typical of
this taxonomic unit than that of G. sarmicntoi, the name
G. trinidadensis Gandolfi is used herein. Gandolfi’s (1955
illustrations of the holotype of G. trinidadensis ave some-
what distorted. Hence, new illustrations were prepared of
the holotype herein (Text-figure 57) .
Form analysis data for G. trinidadensis Gandolfi are
presented in Text-figure 56. G. trinidadensis is similar to
G. fornicata Plummer in thin-section and shows similar
T’X/TX values (mean T’X/TX value for 19 measured
specimens = 0.422) . It can be readily differentiated from G.
fornicata in thin-section: (1) by the vaulted nature of the
spiral surfaces of its chambers; (2) by the imperforate,
| : = x ene
0.154 f0.098 shoo 112]0.090]0.170]0.150]0. 140[0.127 fo.
— 127 |0.154
PE 686
MX 174
Trinidad
Bolli 1944
E 682
xX 78
PE 683
MX 174
P)
MX
-518 o.aeslo. 41510.420]0.590]0.501]0.555]0.428
nN
ine}
to
Nm
IS
NR
+
NR
Pal
=)
°
-
i)
Nh
cy
}°
Ww
2)
°
°
0.205
Be
Upper Cretaceous of Tunisia.
radial hyaline character of large portions of its early whorls;
and (3) by the weak nature of the umbilical rim of its
double keel in earlier whorls. Externally the differences
are apparent. G. trinidadensis lacks the crenulate or plicate
spiral chamber surfaces present in G. fornicata. Textfig-
ure 35 suggests that G. trinidadensis Gandolfi evolved from
G. arca (Cushman). Though this phylogenic link cannot be
as firmly established as suggested in Textfigure 35, some
evidence can be cited in its support. For example, G. trini-
dadensis seems to show G. arca type of keel structure (cf.
type 1, Text-figure 40) in its early whorls. In addition G,.
trinidadensis sometimes shows G. arca-like radial hyaline
imperforate early whorls. It is still possible, however, that
this species evolved from G. fornicata as suggested by Bolli
(1951, p. 189, G. caliciformis, Table 1)
362 PALAKONTOGRAPHICA AMERICANA (V, 37)
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert subzone to A. mayaroensis subzone.
Occurrence.—In Mexico this species has been observed
in the Late Maestrichtian (A. mayaroensis subzone) por-
tion of the Méndez shale and in deposits of the late
Middle Maestrichtian age (upper part of G. gansseri sub-
zone) north of Mamulique Pass along the Mexico, D.F.—
Nuevo Laredo Highway (Rt. 85).
In Texas G. trinidadensis occurs abundantly in the
Corsicana marl of Travis and Navarro Counties and in the
Kemp clay of Travis and Falls County.
In southwestern Arkansas it has been observed only
in the Arkadelphia marl of Hempstead County.
In the West Indies G. trinidadensis Gandolfi was fig-
ured and recorded from the Guayaguayare formation of
Trinidad by Bolli (1951, 1957) under the name of G.
caliciformis (de Lapparent). In Trinidad Bolli (1957, p.
53, fig. 10), noted that the species is restricted to the G.
ganssert and A. mayaroensis subzones.
Gandolfi originally described this form from the Colon
formation of Colombia. It is also known from the Upper
Cretaceous of France and from the mid-Pacific guyot area.
Globotruncana ventricosa White
Plate 75, figures 21-26; Plate 79, figures 9-14; Plate 95, figures
10, 11; Plate 99, figure 2
1928b. Globotruncana canaliculata var. ventricosa White, Jour. Pal-
eont., vol. 2, No. 4, p. 284, pl. 38, figs. 3a-c.
1932. Globotruncana canaliculata (Reuss), Sandidge, Jour. Paleont.,
vol. 6, No. 3, pp. 284, 285, pl. 44, figs. 3-5.
1941. Globotruncana linnei tricarinata (Quereau), Vogler (part)
Paleontographica, Suppl. Bd. 4, Abt. 4, p. 287, pl. 23, figs. 29,
30; not figs. 22-28, 31.
1946. Globotruncana ventricosa White, Cushman, U.S. Geol. Sur., Prof.
Paper, No. 206, p. 150, pl. 62, figs. 3a-c.
1953. Globotruncana fundiconulosa Subbotina (part), Trudy, Vses.
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76,
p- 200, pl. 14, figs. 4a-c; not figs. la-3c [=M. concavata (Brot-
zen) }.
1953. Globotruncana rosetta (Carsey), Subbotina (part), Trudy, Vses,
Neft. Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p.
197, pl. 13, figs. 5a-c, not 6a-c.
1953. Not Globotruncana ventricosa White, Subbotina, Trudy Vses.
Neft. Naukno, Issled. Geol.—Razved. Instit., n. ser., vol. 76,
p- 194, pl. 13, figs. la-4c.
1953. Globotruncana lobata de Klasz, Contr. Cushman Found. Foram.
Res., vol. 6, pt. 1, p. 43, pl. 7, figs. 2a-c.
1955. Not Globotruncana ventricosa ventricosa White, Dalbiez, Mi-
cropaleont., vol. 1, No. 2, p. 168, text-figs. 7a-d [=M. concavata
(Brotzen)].
1955. Not Globotruncana ventricosa carinata Dalbiez, Micropaleont.,
vol. 1, No. 2, pp. 168, 169, text-figs. 8a-d [=M. concavata (Brot-
zen)].
1955. Not Globotruncana ventricosa ventricosa White, Gandolfi, Bull.
Amer. Paleont., vol. 36, No. 155, p. 22, pl. 1, figs. 5a-c=G.
rosetta (Carsey).
1957. Globotruncana (Globotruncana) paraventricosa (Hofker) , Ed-
gell, Micropaleont., vol. 3, No. 2, p. 114, pl. 1, figs. 1-3.
1957. Globotruncana ventricosa White, Bolli, U.S. Nat. Mus., Bull.
No. 215, p. 57, pl. 13, figs. 4a-c.
TEXT-FIGURE 60:
Globotruncana
ventricosa
PE 807
291-A
TX
57.
o
17.0°
°
pon
S o
° nN
vt
is
o
wo
a
g
double
Eee at D!
Da=D"
Dp-D'b
All measurements in millimeters.
* Da-D', = diameter of last whorl, D,-D'|, = diameter of next to last whorl.
1957. Globotruncana ventricosa White, Sacal and Debourle (part),
Soc. Géol. France, n. sér., Mém. No. 78, p. 62, pl. 27, ?fig. 3;
figs. 5, 13; not fig. 14.
1959. Globotruncana tricarinata (Quereau), Ayala, Univ. Nacional
Aut. Mexico, Instit. Geol., Paleont. Mexicana, No. 4, p. 24, pl.
7, fig. 2
1959. Globotruncana ventricosa White, Ayala, Univ. Nacional Aut.
Mexico, Instit. Geol., Paleont. Mexicana, No. 4, pp. 26, 27, pl. 6,
fig. 5.
1959. Globotruncana rosetta (Carsey), Ayala (part), Univ. Nacional
Aut. Mexico, Instit. Geol., Paleont. Mexicana, No. 4, p. 25, pl. 5,
figs. 2, 3; not pl. 6, fig. 4.
1960. Globotruncana ventricosa ventricosa White, Tollmann, Jahrb.
‘ Geol. Bund., Bd. 103, pp. 195, pl. 196, p. 21, figs. 7a-c.
1961. Not Globotruncana ventricosa White, Graham and Clark, Contr.
usher Found. Foram. Res., vol. 12, pt. 3, p. 112, pl. 5, figs.
Ya-c.
1962. Globotruncana cf. ventricosa White, Barr, Paleontology, vol. 4,
pt. 4, pp. 577-578, pl. 71, figs. 2a-c.
Description.—Test low trochospire, planoconyex (mean
T’X/TX value for 13 specimens = 2.65), truncated by wide
double keel [G. linneiana (d’Orbigny) -type] which follows
a distinctly lobulate spiral periphery. Preceding whorls
usually showing a well-developed G. linneiana (d’Orbigny)
stage of development in thin-section (cf. Plate 95, figures 10,
11). Embryonic whorl of chambers globigeriniform, lacking
a double keel. Chambers arranged in two and one-half
to three whorls which gradually expand in size; six to
nine chambers in the last whorl. Chambers spirally typically
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TEXT-FIGURE 59:
All measurements in millimeters
elevata (Brotzen)
Transitional to G.
ve
GuLrF GrRETACEOUS FORAMINIFERA: PESSAGNO $63
planoform, petaloid to crescent-shaped, closely resembling
those of G. linneiana (d’Orbigny); separated by curved,
raised, coarsely beaded sutures; chambers umbilically highly
convex, crudely subrectangular; separated by slightly de-
pressed, curved, finely beaded to nonbeaded sutures. Um-
bilicus, deep, bordered by well-developed, often coarsely
beaded umbilical shoulder; covered by spiral system of
tegilla displaying infralaminal and intralaminal accessory
apertures. Primary aperture interiomarginal, umbilical in
position. Chamber surfaces relatively smooth spirally except
for coarsely beaded sutures, but umbilically occasionally
showing abundant, nonaligned rugosities on first several
chambers of final whorl. Outer wall except for double keel
radial hyaline, imperforate showing ultragranular hyaline,
imperforate calcite on outer portions of spiral and umbilical
rims (variety of type 2; Text-figure 40). Rugosities and
beads ultragranular hyaline, imperforate. Septal walls and
tegilla microgranular hyaline, finely perforate.
Remarks.—Abundant topotypes of G. ventricosa White
were collected and examined during the course of this
study. A number of topotypes have been illustrated herein.
As previously noted, G. ventricosa has often been con-
fused by various workers with M. concavata (Brotzen) . Cri-
teria for separating these species both externally and in
thin-section have been presented under M.
(Brotzen). In terms of the form analysis data presented
in Text-figures 20 and 60 for these two species, they seem
to be most readily separated on the basis of their D,-D’,/
D.-D’, values (cf. Text-figure 61) .7
G. lobata de Klasz (1953) is regarded as a junior
synonym of G. ventricosa White. Larger gerontic speci-
concavata
mens similar to G. lobata de Klasz occur in material from
the type locality of G. ventricosa. Furthermore, both De
Klasz’s form and G. ventricosa have the same geologic
range. The holotype of G. lobata de Klasz was examined in
the collections of the U. S. National Museum during the
course of this study.
G. ventricosa differs from G. rosetta (Carsey) (1) by
possessing more petaloid chambers spirally which are
separated by highly beaded sutures; (2) by being more in-
flated umbilically and thus having higher T’X/TX values;
and (3) by having a wide double keel instead of a narrow
double keel which invariably merges to form a single keel.
Both species share G. linneiana (d’Orbigny) early stages
and appear to have evolved from this latter species (Text-
figure 35).
Range.—G. fornicata—stuartiformis assemblage zone:
7D,-D’,—diameter of final whorl.
D,-D’,—diameter of preceding whorl.
0 = ———— — —— Ss
“|
90
|
|
oF
°
- °
x 6 °
x >
sok °
°
40h » ° °
.
‘i »
ho » 52 |
» .
| »
Ib sO 6 °
vor
a SEN ee ey
FEL pL Ean R ee DA ein teen Ie Siz NS TS 2S) SS TS
A, blowi subzone (D. multicostata zonule) to G. elevata
subzone (G. calcarata zonule). This species is much more
abundant in the G. elevata subzone than it is in the A.
blow: Subzone.
Occurence.—The type locality of G. ventricosa near Bar-
ranco, Mexico was relocated as accurately as_ possible
during the course of this study (see TYPE 4, Appendix)
and abundant topotypic material was collected. The fauna
at TYPE 4 includes the following species:
Globotruncana calcarata Cushman
ventricosa White
elevata (Brotzen)
fornicata Plummer
rosetta (Carsey)
stuartiformis Dalbiez
stephensoni Pessagno, n. sp.
Rugotruncana subcircumnodifer (Gandolfi)
Globotruncana nothi (Bronnimann and Brown)
Rugoglobigerina rugosa (Plummer)
Pseudoguembelina costulata (Cushman)
Pseudotextularia elegans (Rzehak)
Globigerinelloides prairichillensis Pessagno, n. sp.
yaucoensis (Pessagno)
and other forms indicative of the G. elevata subzone, G.
calcarata zonule and a Late Campanian age.
In Mexico G. ventricosa has been observed in the Early
Campanian portion of the San Felipe formation at the
type locality of this unit near San Felipe east of Ciudad
Valles. It was also observed at numerous localities in the
Méndez shale in the Tampico area and the Sierra Madre
Oriental. It occurs in the Papagallos shale strata of Late
Campanian age along the Mexico, D.F.—Nuevo Laredo
Highway (Rt. 85) north of Mamulique Pass.
In Texas G. ventricosa has been observed in this study
in the “Lower Taylor marl” of McLennan County; the
564 PALAEONTOGRAPHICA AMERICANA (V, 37)
Pecan Gap chalk of McLennan County; and the “Upper
Taylor marl” of Limestone and Travis Counties. It also has
been observed in sample number 52 of Cushman (1946, p.
3). Cushman (ibid.) stated that this sample is from the Ney-
landville marl of Delta County. No specimens of this
species were observed in samples from the Neylandville
marl of Navarro County.
In southwestern Arkansas G. ventricosa has been noted
in the lower part of the Brownstown marl (AR 7-A; see
Appendix) and in the Annona chalk (AR 6; see Appen-
dix) .
In the West Indies G. ventricosa is known from the
Campanian of Haiti (cf. Ayala, 1959) and from the
Campanian portion of the Naparima Hill formation of
Trinidad (cf. Bolli, 1957, p. 53).
This species is known elsewhere from the Campanian
of France, the Isle of Wight, Russia, Bavaria, and Australia.
It also has been figured by Vogler (1951) under the name
of G. linnei tricarinata from the Upper Cretaceous of the
East Indies.
Genus RUGOGLOBIGERINA Bronnimann, 1952
Type species: Globigerina rugosa Plummer, 1927.
1952. Rugoglobigerina Bronnimann, Bull. Amer. Paleont., vol. 34, No.
140, p. 16.
1952. Trinitella Bronnimann, Bull. Amer. Paleont., vol. 34, No. 140,
p- 56.
1952. Plummerita Bronnimann, Contr. Cushman Found. Foram. Res.,
vol. 3, pts. 3, 4, p. 146.
1956. Kuglerina Bronnimann and Brown, Eclogae Geol. Helv., vol. 48,
No. 2, p. 557.
1957. Rugoglobigerina Bronnimann, Bolli, ef al. (part), U.S. Nat.
Mus., Bull., No. 215, pp. 43, 44.
1960. Rugoglobigerina Bronnimann, Banner and Blow (part),
Paleontology, vol. 2, pt. 1, p. Il.
1964. Rugoglobigerina Bronnimann, Loeblich and ‘Tappan, (part)
Treatise on Inyert. Paleont., vol. 2, pt. C, Protista 2, p. C663.
Emended definition.—Test trochospiral, biconvex to
spiroconvex; chambers usually spherical or ovoidal;
occasionally partially angled. Sutures radial, depressed,
never beaded, curved to nearly straight spirally and umbili-
cally. Periphery occasionally with imperforate peripheral
band or weak double keel. Ornamentation always consist-
ing of rugosities or costellae aligned in a meridorial pat-
tern. Umbilicus covered by spiral system of tegilla with
intralaminal and infralaminal accessory apertures. Primary
aperture interiomarginal, umbilical in position. Outer
wall radial hyaline perforate except for double keel,
imperforate peripheral bands, and rugosities. Imperforate
peripheral bands radial hyaline. Double keels having
radial hyaline base (equivalent to imperforate peripheral
band) and rims consisting dominantly of ultragranular
hyaline imperforate calcite. Rugosities ultragranular hya-
line, imperforate. Septal walls and tegilla microgranular
hyaline, finely perforate.
Remarks.—Rugoglobigerina Bronnimann differs from
Archaeoglobigerina Pessagno, n. genus by possessing cos-
tellae or rugosities which are aligned in a meridorial
pattern. Species of both genera may show weakly devel-
oped double keels which do little to truncate the periph-
eral margins of their globigeriform tests.
Rugoglobigerina evolved from Archaeoglobigerina
during Early Campanian times (Ad. blowi subzone, P.
glabrata zonule) through the acquisition of meridorially
aligned rugosities or costellae (Text-figure 26). Whereas
Archaeoglobigerina gave rise to Globotruncana Cushman,
Rugoglobigerina gave rise to Rugotruncana Bronnimann
and Brown. This is perhaps the best case of parallel evo-
lution among the planktonic Foraminifera.
Range.—G. fornicata—stuartiformis assemblage zone,
A. blowi subzone (P. glabrata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
The first appearance of common Rugoglobigerina in
the P. glabrata zonule serves as one useful criterion for
separating this zonule from the underlying D. multicostata
zonule in Early Campanian strata of the Gulf Coast and
the West Indies.
Occurrence.—Campanian and Maestrichtian — strata;
world-wide. This species does not occur in strata older
than Campanian age in the Gulf Coast and West Indies
sections. All older occurrences of Rugoglobigerina when
carefully investigated include forms herein assignable to
other genera such as Archaeoglobigerina, n. genus, Hed-
bergella, and others.
Rugoglobigerina hexacamerata Bronnimann
Plate 74, figure 4; Plate 91, figures 5-7
1952. Rugoglobigerina reicheli hexacamerata Bronnimann, Bull.
Amer. Paleont., vol. 34, No. 140, pp. 23-25, pl. 2, figures 10-12;
text-figure 8: figs. a-m.
1955. Globotruncana (Rugoglobigerina) hexacamerata subhexacam-
erata Gandolfi, Bull. Amer. Paleont., vol. 36, No. 155, p. 34, pl.
1, figs. 1la-c.
Remarks.—Rugoglobigerina hexacamerata Bronniman
is one of the more distinctive species of Rugoglobigerina. It
differs from Rugoglobigerina reicheli Bronnimann by pos-
sessing (1) a less spinose periphery; (2) a greater number
of chambers in the last whorl (six to seven as opposed to
four or five); (3) and chambers which gradually increase
in size throughout two whorls. It differs from R. rugosa
(Plummer) (1) by being much lower spired; (2) by
having a much thinner test measured along the axis of
GULF CREVTACEOUS FORAMINIFERA: PESSAGNO 365
coiling (T-T’); (3) by having chambers which increase
gradually in size; and (4) by being smaller and more
spinose.
The writer has examined the holotype of R. reicheli
hexacamerata Bronnimann in the collections of the U.S.
National Museum, Washington, D.C. An examination of
the holotype of G. (R.) hexacamerata subhexacamerata
Gandolfi (No. 20831) in the Paleontological Research
Institution, Ithaca, New York, indicates that it differs
from R. hexacamerata s.s. only by its possession of a
weakly developed double keel ‘on the first several cham-
bers of the last whorl. Weakly developed double keels
occur occasionally on most species of Rugoglobigerina and
seem to represent mere variants in a species population.
Range.—G. contusa—stuartiformis assemblage zone: G.
gansseri subzone to A. mayaroensis subzone.
Occurrence.—In Mexico this species has been observed
in the Late Maestrichtian (A. mayaroensis subzone) por-
tion of the Méndez shale in the Tampico area and in
Middle Maestrichtian (upper part of G. gansseri subzone)
portion of the Papagallos shale (MX 174; see Appendix)
occurring north of Mamulique Pass and south of Nuevo
Laredo on the Mexico, D.F.—Nuevo Laredo Highway (Rt.
85).
In Texas R. hexacamerata was noted in the Corsicana
marl of Travis and Navarro Counties and in the Kemp
clay of Falls County.
In southwestern Arkansas it occurs in the Arkadelphia
marl of Hempstead County.
R. hexacamerata was originally described by Bronni-
mann (1952) from the Late Maestrichtian portion of the
Guayaguayare formation of ‘Trinidad. It is also known
from the Maestrichtian Colon formation of Colombia.
Rugoglobigerina reicheli Bronnimann
Plate 65, figures 5-7; Plate 91, figure 3
1952. Rugoglobigerina reicheli reicheli Bronnimann, Bull. Amer.
Paleont., vol. 34, No. 140, pp. 18-20, pl. 3, figs. 10-12; text-fig. 4:
figs. a-m; text-fig. 5: figs. a-c.
Remarks.—Rugoglobigerina vreicheli_ s.s. Bronnimann
differs from Rugoglobigerina rugosa (Plummer) (1) by
the markedly spinose and often clavate character of the
early chambers of its final whorl and (2) by the thinner
nature of its test (measured along the axis of coiling
T-T’). A comparison of this species to R. hexacamerata
Bronnimann has been presented under the remarks on
the latter species.
The writer has examined the holotype of R. reicheli
reicheli Bronnimann at the U.S. National Museum, Wash-
ington, D.C.
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert subzone to A. mayaroensis subzone.
Occurrence.—In the present study R. reicheli has been
observed in Mexico in Middle Maestrichtian Papagallos
shale deposits (upper part of G. gansseri subzone) (MX
174; see Appendix) north of Mamulique Pass along the
Mexico, D.F.—Nuevo Laredo Highway (Rt. 85). It has
not been observed in the Tampico region to the south.
In Texas R. reicheli has been observed only in the
Kemp clay of Falls County (TX 267A-C and TX 268; see
Appendix). It also occurs in the Arkadelphia marl of
southwestern Arkansas (AR 8; see Appendix) .
Bronnimann (1952 ) originally described this species
from the Late Maestrichtian (4. mayaroensis Subzone) part
of the Guayaguayare formation of Trinidad.
Rugoglobigerina rotundata Bronnimann
Plate 65, figures 1-3; 4; Plate 68, figures 1-3
1952. Rugoglobigerina rugosa rotundata Bronnimann, Bull. Amer.
Paleont., vol. 34, No. 140, pp. 34-36, pl. 4, figs. 7-9; text-fig. 15;
figs. a-e; text-fig. 16: figs. a-c.
1955. Globotruncana (Rugoglobigerina) rotundata rotundata (Bronni-
mann), Gandolfi, Bull. Amer. Paleont., vol. 36, No. 135, p. 70,
pl. 7, figs. 2a-c.
1956. Kuglerina rotundata (Bronnimann), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, p. 557.
Remarks.—This distinctive species has been adequately
described by Bronnimann (1952) and by Bronnimann
and Brown (1956). It differs from other species of Rugo-
globigerina by the globular nature of its test and by its
considerably smaller umbilicus.
Bronnimann and Brown (1956, p. 557) designated
this species as the type species of Kuglerina Bronnimann
and Brown. They stated that Kuglerina differs from Rugo-
globigerina by being “higher spired”; by having a smaller,
deeper umbilicus; and by lacking an umbilical cover plate.
As noted by Bolli, et al. (1957, p. 44), the first of these
two characteristics are of only specific importance. Further-
more, tegilla with infralaminal and intralaminal acces-
sory apertures have been observed by the writer on well-
preserved specimens of this species from the Kemp clay of
Falls County, Texas.
During the course of this study, the writer exam-
ined the holotype of R. rugosa rotundata in the collections
of the U.S. National Museum, Washington, D.C., as well
as abundant comparative material from the Guayaguayare
formation of Trinidad.
366 PALAEONTOGRAPHICA AMERICANA (V, 37)
Range.—G. contusa—stuartiformis assemblage zone:
upper part of G. gansseri subzone to A. mayaroensis sub-
zone.
Occurrence.—In Mexico this species has been observed
in the Late Maestrichtian (A. mayaroensis subzone) por-
tion of the Méndez shale of the Tampico area. It also occurs
north of Monterrey and Mamulique Pass along the Mex-
ico, D.F._Nuevo Laredo Highway (Rt. 85) in the Middle
Maestrichtian portion of the Papagallos shale (MX 174; see
Appendix) .
In Texas R. rotundata has only been observed in the
uppermost part of the Kemp clay of Falls County from
immediately below to about 20 feet below the Midway
(Kincaid) —Kemp clay contact. Here it is associated with
Globotruncana conica White, Globotruncana stuarti S.s.,
Racemiguembelina fructicosa (Egger) and other species
that make their first appearance in the upper part of the
G. gansseri: subzone in both Texas and northern Mexico.
This species was originally recorded by Bronnimann
(1952) from the Late Maestrichtian (A. mayaroensis sub-
zone) portion of the Guayaguayare formation of Trinidad.
It has also been figured by Gandolfi (1955) from the
Maestrichtian Colon formation of Colombia.
As far as the writer is aware, this species has not yet
been figured from the Maestrichtian deposits of Eurasia,
Africa, or Australia.
Rugoglobigerina rugosa (Plummer)
Plate 75, figures 2-3; Plate 101, figures 8, 9
1927. Globigerina rugosa Plummer, Univ. Texas, Bull. 2644, p. 38,
pl. 2, fig. 10.
1931. Globigerina rugosa
3101, pp. 194, 195.
1952. Rugoglobigerina rugosa pennyi Bronnimann, Bull. Amer. Pale-
Amer. Paleont., vol. 34, No. 140, pp. 28-33, text-fig. 11: figs. a-i;
text-fig. 12: figs. a-i; text-fig. 13: figs. a-i.
1952. Rugoglobigerina rugosa pennyi Bronnimann, Bull. Amer. Pale-
ont., vol. 34, No. 140, p. 34, pl. 4, figs. 1-3; text-fig. 14: figs.
a-i.
1952. Rugoglobigerina macrocephala ornata Bronnimann, Bull. Amer.
Paleont., vol. 34, No. 140, pp. 27, 28, pl. 2, figs. 4-6; text-fig.
10: a-i.
1952. Rugoglobigerina reicheli pustulata Bronnimann, Bull. Amer.
Paleont., vol. 34, No. 140, pp. 20-23, pl. 2, figs. 7-9; text-fig. 6:
figs. a-m; text-fig. 7: figs. a-1.
1953. Rugoglobigerina rugosa rugosa (Plummer) ,
Paleont., vol. 27, No. 2, p. 227, p. 30, figs. 1-3.
1955. Globotruncana (Rugoglobigerina) rugosa rugosa (Plummer) ,
Gandolfi, Bull. Amer. Paleont., vol. 36, No. 155, p. 72, pl. 7, figs.
6a-c.
1955. Globotruncana (Rugoglobigerina) ornata subornata Gandolfi,
Bull. Amer Paleont., vol. 36, No. 155, p. 50, pl. 3, figs. 6a-c.
1955. Globotruncana (Rugoglobigerina) rugosa subrugosa Gandolfi,
Bull. Amer. Paleont., vol. 36, No. 155, p. 72, pl. 7, figs. 5a-c.
1957. Rugoglobigerina rugosa (Plummer) , Bolli, e¢ al., U.S. Nat. Mus.,
Bull., No. 215, pp. 43, 44, pl. 11, figs. 2a-c.
1960. Rugoglobigerina rugosa rugosa Plummer, Olsson, Jour. Paleont.,
vol. 34, No. 1, p. 50, pl. 10, figs. 16-18.
1960. Rugoglobigerina reicheli pustulata Bronnimann, Olsson, Jour.
Paleont., vol. 34, No. 1, p. 50, pl. 10, figs. 13-15.
Plummer, Plummer, Univ. Texas, Bull.
Hamilton, Jour.
1961. Rugoglobigerina rugosa rugosa (Plummer), Corminboeuf, Ec-
logae. Geol. Helv., vol. 54, No. 1, p. 119, pl. 2, figs. 5a-c.
1961. Rugoglobigerina macrocephala ornata Bronnimann, Cormin-
boeuf, Eclogae Geol. Helv., vol. 54, No. 1, p. 118, pl. 2, figs. 4a-c.
1961. 2? Rugoglobigerina rugosa (Plummer) , Graham and Clark, Contr.
Cushman Found. Foram. Res., vol. 12, pt 3, p. 111, pl. 5, figs.
la-c (illustrations show an extraumbilical primary aperture).
1962. Rugoglobigerina rugosa subrugosa Gandolfi, Pessagno, Micro-
paleont., vol. 8, No. 3, p. 360. pl. 6, figs. 10-12.
1962. Rugoglobigerina rugosa (Plummer), Pessagno, Micropaleont.,
vol. 8, No. 3, p. 360, pl. 5, fig. 13.
1962. Rugoglobigerina rugosa rugosa (Plummer), Herm, Bayer. Akad.
Wiss., Math.—Nat. KI., Abh., No. 104, p. 60, pl. 3, fig. 2.
1962. Rugoglobigerina pustulata Bronnimann, Berggren (part) , Stock-
holm Contr. Geol., vol. 9, No. 1, pp. 78-80, pl. 13, figs. la-e;
not text-fig. 10: figs. 7-12.
1962. Rugoglobigerina rugosa (Plummer). Berggren, Stockholm Contr.
Geol., vol. 9, No. 1, pp. 71-75, pl. 11, figs. la-5b; text-fig. 8:
figs. 1-5c.
1962. Rugoglobigerina macrocephala Bronnimann, Berggren (part),
Stockholm Contr. Geol., vol. 9, No. 1, pp. 76-78, pl. 12, figs.
4a-6c; text-fig. 9: la-5; not text-fig. 10, figs. 1-5.
1963. Rugoglobigerina rugosa rugosa (Plummer), Bronnimann and
Rigassi, Eclogae Geol. Hely., vol. 56, No. 1, pl. 18, figs. la-c
(no pagination) .
1964. Rugoglobigerina rugosa rugosa (Plummer), Olsson, Micropal-
eont., vol. 10, No. 2, p. 173, pl. 7, figs. 3a-4c; ?2a-c; Pba-c.
1964. Rugoglobigerina macrocephala (Bronnimann), Olsson, Micro-
paleont., vol. 10, No. 2, p. 172, pl. 6, figs. 9a-c.
1964. Rugoglobigerina rugosa (Plummer), Loeblich and Tappan,
Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2, p. C663, fig.
530: 3a-c.
1964. Rugoglobigerina rugosa (Plummer), Said and Sabry, Micropal-
eont., vol. 10, No. 3, p. 386, pl. 3, figs. 18a-c. '
Remarks.—The writer has examined the syntypes of
Plummer (1927) (Nos. 20739-
20742 PRI). He has also examined the holotypes of
Rugoglobigerina macrocephala ornata Bronnimann, Rugo-
of Globigerina rugosa
globigerina —macrocephala macrocephala Bronnimann,
Rugoglobigerina reicheli pustulata’ Bronnimann, and
Rugoglobigerina rugosa pennyi Bronnimann at the U.S.
National Museum, Washington, D.C. At present, it is
felt that all of these forms except for R. macrocephala s.s.
(cf. Pl. 66, figs. 1-2) should be treated as variants of R.
rugosa (Plummer). R. macrocephala s.s. is regarded as a
valid species although it is often difficult to separate from
R. rugosa.
G. (R.) rugosa subrugosa Gandolfi (holotype, No.
20863 PRI) is treated as a variant of R. rugosa. Its double
keel is weakly developed and does not truncate the test
periphery.
Range.—G. fornicata—stuartiformis assemblage zone:
A. blowi subzone (P. glabrata zonule) to G. contusa—
stuartiformis assemblage zone: A. mayaroensis subzone.
Occurrence.—In Mexico R. rugosa is common to abun-
dant throughout the Campanian and Maestrichtian por-
tions of the Méndez shale. It also occurs in Campanian
and Maestrichtian portion of the Papagallos shale north of
Mamulique Pass along the Mexico, D.F.—Nuevo Laredo
Highway.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 367
In Texas R. rugosa occurs in the “Lower ‘Taylor marl”
of Travis, McLennan, Dallas, and Ellis Counties; the
Wolfe City sand of McLennan and Falls Counties; the
“Upper Taylor marl” of Travis and Limestone Counties;
the Upson clay of Maverick County; the Neylandville marl
of Navarro and Delta Counties; the Corsicana marl of
Travis and Navarro Counties; and the Kemp clay of
Travis, and Falls Counties.
In southwestern Arkansas it occurs in the Browns-
town marl of Sevier County; the Ozan formation of Sevier
County; the Annona chalk of Sevier County; the Marlbrook
marl of Howard County; the Saratoga chalk of Howard
County; and the Arkadelphia marl of Hempstead County.
Elsewhere in North America it is known from the
Navesink, Mt. Laurel, and Red Bank formations of New
Jersey (cf. Olsson 1960, 1964) .
In the West Indies it has been recorded from the
Via Blanca and Penalver formations (Habana Group) of
Cuba by Bronnimann and Rigassi (1963); from the Rio
Yauco formation, Rio Blanco formation, and Parguera
limestone of Puerto Rico by Pessagno (1960, 1962); and
in the Guayaguayare and Naparima Hill formations o!
Trinidad by Bronnimann (1952). Elsewhere in the West-
ern Hemisphere, it was figured by Gandolfi (1955) from
the Colon formation of Colombia.
R. rugosa is well known in the Campanian and Mae-
strichtian deposits of Eurasia and Africa. It also has been
noted in submarine core samples by Hamilton (1953) from
the Mid-Pacific guyot area.
Rugoglobigerina scotti (Bronnimann)
Plate 74, figures 9-14; Plate 75, figures 4-6
1952. Trinitella scolli Bronnimann, Bull. Amer. Paleont., vol. 34,
No. 140, p. 57, pl. 4, figs. 4-6; text-fig. 30: figs. a-m.
1956. Trinitella scotti Bronnimann, Bronnimann and Brown, Eclogae
Geol. Helv., vol. 48, No. 2, p. 555, pl. 23, figs. 13-15; pl. 24,
fig 3.
1957. Rugoglobigerina scotti (Bronnimann) , Bolli, et al., U.S. Nat.
Mus. Bull. No. 215, p. 43, pl. 11, figs. 3a-4c.
1961. Trinitella scotti Bronnimann, Corminboeuf, Eclogae Geol. Helv.,
vol. 54, No. 1, pp. 119, 120, pl. 2, figs. Ga-c.
1963. Trinitella scotti Bronnimann, Bronnimann and Rigassi, Eclogae
Geol. Helv., vol. 56, No. 1, pl. 16, figs. 3a-c.
1964. Trinitella scotti Bronnimann, Olsson, Micropaleont. vol. 10,
No. 2, p. 173, pl. 6, figs. 10a-c.
1964. Trinitella scotti Bronnimann, Loeblich and Tappan, Treatise
on Invert. Paleont., pt. C, Protista 2, vol. 2, p. C663, fig. 530:
2a-c (p. C662) .
Remarks.—The writer sees no reason at present to
separate Trinitella from Rugoglobigerina. Although T.
scotti possesses final chambers that are flattened spirally
producing a subangular periphery, it is little different in
character from other species of Rugoglobigerina. Its cham-
bers like those of Rugoglobigerina are for the most part
globigeriniform; separated spirally and umbilically by de-
pressed sutures; and possess rugosities or costellae arranged
in a meridorial pattern.
Range.—G._ fornicata—stuartiformis assemblage zone,
R. subcircumnodifer subzone (R. subpennyi zonule) to G.
contusa—stuartiformis assemblage zone, A. mayaroensis sub-
zone.
Occurrence.—In Mexico, R. scotti has been observed
only in the Tampico area in Méndez strata assignable to
the Late Maestrichtian 4. mayaroensis subzone. North of
Monterrey and Mamulique Pass it occurs in Papagallos
shale strata which are assignable to the upper part of the G.
gansseri subzone (MX 174, see Appendix) .
In Texas R. scotti occurs in the Middle Maestrichtian
(G. gansseri subzone) Corsicana marl of Travis and Nay-
arro Counties and in the Kemp clay of Falls County.
Elsewhere in North America this species has been re-
corded by Olsson (1964, p. 74) from the Redbank forma-
tion of New Jersey.
In the West Indies, R. scotti has been recorded by
Bronnimann and Rigassi (1963, p- 261) from the Mae-
strichtian Penalver formation (Habana Group) of Cuba; by
Pessagno (1960, p. 91) from the Early Maestrichtian portion
(R. subcircumnodifer subzone) of the Rio Yauco forma-
tion and the Parguera limestone of Puerto Rico; and by
Bronnimann (1952, text-fig. 1, p. 51) in the Late Mae-
strichtian (4. mayaroensis subzone) and possibly the Mid-
dle Maestrichtian (G. gansseri subzone) portions of the
Guayaguayare formation in Trinidad.
Rugoglobigerina tradinghousensis Pessagno, n. sp.
Plate 64, figures 1-8
Description.—Test trochospiral, typically spiroconvex,
comprised of three whorls of spherical chambers; three or
five chambers in final whorl. Earlier whorls coiled in higher
plane than final whorl; typically offset above the plane of
coiling of final whorl. Early whorls strongly rugose with ru-
gosities or costellae arranged meridorially; last whorl more
weakly rugose, sometimes completely lacking rugosities. Um-
bilicus small, deep, covered by spiral system of tegilla with
infralaminal and intralaminal accessory apertures in well-
preserved specimens. Primary aperture interiomarginal,
umbilical in position. Outer wall except for rugosities
radial hyaline, perforate. Rugosities ultragranular hyaline,
imperforate. Septal walls and tegilla microgranular hyaline,
finely perforate.
Remarks.—Rugoglobigerina tradinghousensis Pessagno,
n. sp. differs from Rugoglobigerina rugosa (Plummer) (1)
368 PALAEONTOGRAPHICA AMERICANA (V, 37)
by possessing a distinctly smaller and deeper umbilicus; (2)
by being higher spired; and (3) by having only weakly
rugose chambers in its final whorl.
This species is named for Tradinghouse Creek, McLen-
nan County, Texas.
Type locality—Taylor formation ‘Taylor
marl” member). TX 246: Dark gray calcareous mudstone
collected 13.5 feet above level of creek in a section includ-
ing 77.5 feet of exposed strata. Tradinghouse Creek, Mc-
Lennan County, Texas; 1.5 miles due west of juncture be-
tween Tehuacana Creek and Tradinghouse Creek; 1 mile
S65E of Harrison Switch (large meander in ‘Tradinghouse
Creek) , Waco East Quadrangle; USGS 7.5’ quadrangle.
Deposition of types—The holotype and figured para-
types of R. tradinghousensis, n. sp. will be deposited in the
collections of the U.S. National Museum, Washington, D.C.
Unfigured paratypes will be deposited at the Paleontologi-
cal Research Institution, Ithaca, New York.
Range.—G. fornicata—stuartiformis assemblage zone:
A, blowi subzone (P. glabrata zonule) to G. elevata sub-
zone (P. elegans zonule) .
Occurrence.—In ‘Texas, this species has been observed
(“Lower
in the Lower Taylor marl of Travis, McLennan, and Ellis
Counties and in the Wolfe City sand of McLennan County.
In southwestern Arkansas R. tradinghousensis, n. sp.
occurs in the Brownstown marl and the lower part of the
Ozan formation of Sevier County.
Genus RUGOTRUNCANA Bronnimann and Brown, 1956
Type species.—Rugotruncana tilevi Bronnimann and
Brown, 1956 (= Rugotruncana subcircumnodifer (Gan-
dolfi) 1955).
1956. Rugotruncana Bronnimann and Brown, Eclogae Geol. Helv., vol.
48, No. 2, pp. 546, 547.
1959. Globotruncana (Rugotruncana) Bronnimann and Brown, Ban
ner and Blow, Paleontology, vol. 2, pt. 1, p. 11.
1960. Globotruncana (Rugotruncana) Bronnimann and Brown, Pes-
sagno, Micropaleont., vol. 6, No. 1, p. 102.
1962. Globotruncana (Rugotruncana) Bronnimann and Brown, Berg-
gren, Stockholm Contr. Geol., vol. 9, No. 1, p. 67.
Emended definition.—TYest trochospiral, planoconvex
to spiroconvex with periphery truncated by double keel;
double keel often merging to form a single keel at some
time in last whorl. Sutures raised or depressed spirally and
umbilically; usually beaded. Coarse rugosities or costellae,
always arranged in a distinctive meridorial pattern, present
on the surface of test. Early whorls usually showing a
rugoglobigerine stage both externally and in thin-section.
Umbilicus covered by a spiral system of tegilla having both
intralaminal and infralaminal accessory apertures. Primary
aperture interiomarginal, umbilical in position. Outer wall
radial hyaline, perforate except for keel and rugosities.
Keel is both radial hyaline and ultragranular hyaline, im-
perforate when double and predominantly radial hyaline,
imperforate when single. Rugosities ultragranular hyaline,
imperforate. Septal walls and tegilla microgranular hyaline,
finely perforate.
Remarks.—Rugotruncana Bronnimann and Brown is
restricted herein to Globotruncanidae that (1) have their
rugosities or costellae always arranged in a meridorial pat-
tern; (2) have peripheries truncated or angled by double
or single keels; and (3) have rugoglobigerine early stages.
Of the nine species originally included in Rugotrun-
cana by Bronnimann and Brown (1956) only the type
species, Rugotruncana tilevi Bronnimann and Brown, and
Rugotruncana ellisi Bronnimann and Brown possess meri-
dorially arranged rugosities or costellae.
Olsson (1964, p. 159) minimized the importance of
meridorially arranged rugosities or costellae exhibited by
Rugoglobigerina and Rugotruncana and implied that this
is at best only a criterion useful in the separation of taxa
at the species level. He stated (tbid.) that:
A rugosity is actually a coarse flattened spine, but because of preserva-
tion it often appears as a thin ridge when only the base of the spine
is preserved. The meridorial arrangement of rugosities is, basically,
a mathematical problem. The spines of planktonic foraminifera are
usually set normal to the chamber wall and are generally, evenly dis-
tributed over the surface of the test. The radial hyaline wall of these
planktonic organisms undoubtedly controls the arrangement of the
spines.
The writer disagrees with Olsson over many of the
above statements. To begin with, meridorially arranged cos-
tellae or rugosities on Rugoglobigerina and Rugotruncana
are morphologically and phylogenetically unique structures
among the Globigerinacea which are restricted to a par-
Campanian-Maestrichtian stock of the Globo-
truncanidae. The arrangement of the costellae in a distinc-
tive meridorial pattern is a complex morphological feature
ticular
which is governed by an equally complex genetic code.
Furthermore, the meridorial arrangement of the discon-
tinuous costellae is in no way controlled by the packing
of the elongate calcite prisms in the radially hyaline portion
of the test as has been suggested by Olsson. A thorough
investigation of these meridorial arranged ridges by the
writer using thin-sectioning and crushing techniques indi-
cates that they are formed of ultragranular hyaline imper-
forate calcite which has been plastered over the radial
hyaline perforate part of the test (cf. Plate 101, figures
8,9) .8 At high magnifications, using a petrographic micro-
scope, the writer has noted that ultragranular hyaline cal-
8See footnote 1, p. 252.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 369
cite covers and chokes off the large pore frames comprising
the radial hyaline outer surface of the test in much the
same fashion as does the radial hyaline calcite crust layer
secreted by Recent species of Globorotalia s.s. (cf. Bé and
Erickson, 1963, pp. 65-81). The costellae clearly represent
an overlay of ultragranular hyaline calcite and are no way
related to the radial hyaline structure beneath.
Olsson also maintained that the discontinuous rugosi-
ties or costellae represent bases of coarse spines. It is diffi-
cult for the writer to visualize how the often elongate and
fine costellae of Rugoglobigerina and Rugotruncana can
individually represent the bases of stout spines. Stout spines
are present among specimens of Rugoglobigerina reicheli
Bronnimann, but often several of these may originate from
an individual costella.
Rugotruncana as suggested by Bronnimann and Brown
(1956, pp. 522-525) and by Pessagno (1960, pp. 100, 102),
evolved from Rugoglobigerina Bronnimann. As indicated
under Rugoglobigerina many species of the latter genus
such as R. rugosa, R. macrocephala, and R. hexacamerata
may occasionally possess either imperforate peripheral
bands or weakly developed double keels. Many of these
double-keeled variants of Rugoglobigerina [e.g., R. rugosa
subrugosa (Gandolfi), R. subhexacamerata (Gandolfi) }
were first noted by Gandolfi (1955). At some horizons,
particularly in the Lower Maestrichtian (R. subcircum-
nodifer subzone), they are profusely abundant. At this
horizon in the Rio Yauco formation of Puerto Rico, the
writer has noted a completely transitional series of speci-
mens between the double-keeled variant of Rugog obigerina
rugosa [=R. rugosa subrugosa (Gandolfi) |] and Rugotrun-
cana subcircumnodifer (Gandolfi) [—R. tilevi Bronni-
mann and Brown, 1956] and Rugotruncana subpennyt
(Gandolfi) [—R. ganssert dicarinata Pessagno (part) ; see
Pessagno, 1960]. It should be noted that the double-keeled
variant of Rugog'obigerina rugosa does not appear in the
Campanian and Maestrichtian section of the Gulf Coast
until Late Campanian and Early Maestrichtian times.
It is apparent from the analysis of this remarkable
Puerto Rican fauna that Rugoglobigerina gave rise to
Rugotruncana (1) by the flattening of its chambers either
spirally or both spirally and umbilically and (2) by the
development of a strong double keel.
Gandolfi (1955), Berggren (1962), and Olsson (1964)
generally imply that Rugoglobigerina evolved palingeneti-
cally from Globotruncana. For example, Berggren (1962b,
p. 120) maintained that Rugotruncana is descended di-
«
rectly from Globotruncana ‘“—having retained the essen-
tial morphological features of the genus, @.e. primary
carina (e) and coverplates while acquiring a rugoglobigerid
wall structure.” However, it should be pointed out that
some of the species [e.g. G. (R) gansseri Bolli] included
by Berggren under Globotruncana (Rugotruncana) are
not placed under Rugotruncana herein. As species of Rugo-
truncana (under its emended definition herein) such as
R. subcircumnodifer and R. subpennyi all possess well-
developed rugoglobigerine early stages of development, it
is difficult for the writer to visualize how they can be pos-
sibly derived from Globotruncana s.s. As noted in many
places in this monograph, the writer finds little evidence
to support the hypothesis that Rugotruncana evolved from
Globotruncana.
Range.—G. fornicata—stuartiformis assemblage zone,
G. elevata subzone (G. calcarata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
Occurrence.—Late Campanian and Maestrichtian of
North America, West Indies, South America, and Eurasia.
Rugotruncana subcircumnodifer (Gandolfi)
Plate 62, figures 14-16; Plate 74, figures 1-3
1951. Globotruncana cf. globigerinoides Brotzen, Bolli, Jour. Paleont.,
vol. 25, No. 2, p. 198, pl. 35, figs. 16-18.
1955. Globotruncana (Rugoglobigerina) circumnodifer subcircum-
nodifer Gandolfi, Bull. Amer. Paleont., vol. 36, No. 155, p. 44,
pl. 2, figs. 8a-c.
1956. Rugotruncana tilevi Bronnimann and Brown, Eclogae Geol.
Helv., vol. 48, No. 2, p. 547, pl. 22, figs. 1-3.
1956. ? Rugotruncana ellisi Bronnimann and Brown, Eclogae Geol.
Helv., vol. 48, No. 2, p. 547, pl. 22, figs. 7-9.
1960. Globotruncana (Rugotruncana) tilevi Bronnimann and Brown,
Pessagno, Micropaleont., vol. 6, No. 1, p. 102, pl. 5, fig. 10.
1962. Globotruncana (Rugotruncana) tilevi Bronnimann and Brown,
Pessagno, Micropaleont., vol. 8, No. 3, p. 364, pl. 4, figs. 1-3.
1962. Globotruncana (Rugotruncana) — subcircumnodifer Gandolfi,
Berggren, Stockholm Contr. in Geol., vol. 9, No. 1, pp. 67-69,
pl. 10, figs. da-c.
1964. 2? Globotruncana subcircumnodifer Gandolfi, Olsson, Micropale-
ont., vol. 10, No. 2, pp. 170, 171, pl. 6, figs. 1-2; 4-6.
1964. 2? Globotruncana tilevi (Bronniman and Brown), Loeblich and
Tappan, Treatise on Invert. Paleont., pt. C, Protista 2, vol. 2,
p- C662, fig. 529: da-c.
Description.—Test trochospiral, biconvex, mildly lobu-
late, and truncated peripherally by well-developed double
keel. Test consisting of three whorls of chambers; five to
six chambers in the final whorl. Chambers of earlier
whorls typically Rugoglobigerina-like in terms of their
shape and ornamentation. Chambers in final whorl peta-
loid, compressed, subglobular to slightly elevated, beaded
to nonbeaded, curved sutures spirally and umbilically.
Chambers surfaces both spirally and umbilically covered
for most part by meridorially arranged costellae which
may be coarsely spinose; last one or two chambers some-
370 PALAEONTOGRAPHICA AMERICANA (V, 37)
times smooth. Umbilicus moderately deep; covered by a
spiral system of tegilla with intralaminal and infralami-
nal accessory apertures. Primary aperture interiomarginal,
umbilical in position, Outer wall radial hyaline perforate
except for double keels and costellae. Double keels in part
radial hyaline imperforate and in part ultragranular hya-
line imperforate (“variety” of type 2, Text-figure 40) . Cos-
tellae and rugosities ultragranular hyaline imperforate.
Septal walls and tegilla microgranular hyaline, finely per-
forate.
Remarks: As noted by Berggren (1962, pp. 67-69),
R. tilevi Bronnimann and Brown is a junior synonym of
R. subcircumnodifer (Gandolfi). The writer has exam-
ined the holotypes of both species (Paleontological Re-
search Institution, U.S. National Museum)
course of this study.
The specimens figured by Olsson (1964, pl. 6, figs. la-c;
Qa-c) as G. subcircumnodifer Gandolfi and by Loeblich
and Tappan (1964, fig. 529; da-c) as G. tilevi (Bronnimann
and Brown) do not show rugosities or costellae arranged in
a meridorial pattern and thus appear referable to Globo-
truncana rather than to Rugotruncana.
Range.—G. fornicata—stuartiformis assemblage zone,
G. elevata subzone (G. calcarata zonule) to G. contusa—
stuartiformis assemblage zone, A. mayaroensis subzone.
during the
Occurrence.—In Mexico this species occurs in the Late
Campanian and Maestrichtian portions of the Méndez
shale. In Texas it occurs in the “Upper Taylor marl” of
Limestone County; the Upson clay of Maverick County;
the Escondido formation of Maverick County; and_ the
Corsicana marl of Travis and Navarro Counties.
In southwestern Arkansas it has been observed in the
Annona chalk of Sevier County and in the Marlbrook mar]
and Saratoga chalk of Howard County.
Bronnimann and Brown (1956) recorded this species
under the name of R. tilevi from the Late Maestrichtian
A. mayaroensis subzone of Cuba. Pessagno (1960, 1962)
noted abundant specimens of this species under the name
of R. tilevi from the Early Maestrichtian portion of the
Rio Yauco formation of Puerto Rico.
Gandolfi. originally described R. swbcircwmnodifer
(Gandolfi) from the Maestrichtian Colon formation of
Colombia.
In Eurasia R. suwbcircumnodifer has been figured by
Berggren from the Maestrichtian of Denmark.
Rugotruncana subpennyi (Gandolfi)
Plate 76, figures 12-14; Plate 91, figures 8-15
1955. Globotruncana
Bull. Amer. Paleont., vol. 36, No. 155, p.
(mislabeled) .
(ayPlee ls
(Rugoglobigerina) pennyi subpennyi Gandolfi,
figs. 7a-c
1960. Globotruncana (Rugotruncana) gansseri dicarinata Pessagno
(part), Micropaleont., vol. 6, No. 1, p. 103, not pl. 2, figs. 9-11
(=? G. aegyptiaca Nakkady); pl. 3, figs. 1-3; pl. 5, fig. 2.
1962. Globotruncana (Rugotruncana) gansseri dicarinata Pessagno,
Pessagno, Micropaleont., vol. 8, No. 3, Chart 4 (p. 355), pl. 4,
figs 9; OM 2 bs a6:
1964. Not Globotruncana gansseri dicarinata
Micropaleont., vol. 10, No. 2, p.
gansseri Bolli).
1964. 2? Globotruncana aff. G. subcircumnodifer Gandolfi, Olsson,
Micropaleont., vol. 10, No. 2, p. 184, pl. 6, figs. 3a-c.
(Pessagno), Olsson,
166, pl. 3, figs. lac (=G.
Description.—Test trochospiral; spiral side flattened to
mildly convex; ventral side quite convex. Chambers hemi-
spherical in shape; arranged in two and one-half to three
whorls; five to six in final whorl. Chambers
petaloid spirally, separated by slightly curved sutures which
may be either elevated and beaded or somewhat depressed
and nonbeaded. Coarse costellae arranged in a distinctive
meridorial pattern present on spiral and umbilical cham-
ber surfaces though somewhat better developed umbili-
cally. Prominent double keel present throughout much of
ontogeny; often merging to form a single keel in chambers
of last whorl. Umbilicus covered by spiral system of tegilla
chambers
with intralaminal and infralaminal accessory apertures.
Primary aperture interiomarginal, umbilical in position.
Outer wall radial hyaline perforate except for costellae
and keels. Keel when double, both radial hyaline imperfo-
rate and ultragranular hyaline imperforate (‘‘variety” of
type 2, Text-figure 40); when single, radial hyaline im-
perforate. Costellae rugosities ultragranular hyaline imper-
forate. Septal walls and tegilla microgranular hyaline, finely
perforate.
Remarks.—The holotype of G. (R.) gansseri dicarinata
Pessagno was a poor choice of a type specimen as it lacked
rugosities arranged in meridorial pattern and was non-
rugose. It probably is assignable to Globotruncana aegyp-
tiaca Nakkady. The paratypes correspond better to Pessag-
no's description and concept of this form and are definitely
assignable to Rugotruncana subpennyi (Gandolfi) .
The writer has examined the holotype of G. (R.)
pennyi subpennyi (No. 20864) at the Paleontological Re-
search Institution, Ithaca, New York. This form is like
the paratype specimens of G. (R.) gansseri dicarinata Pes-
sagno. It shows hemispherical chambers and a double keel
which generally follows the spiral periphery of the last
whorl, but merges to form a single keel on the last
chamber.
R. subpennyi evolved from a double-keeled variant of
Rugoglobigerina rugosa as noted by Pessagno (1960, p. 100)
by spiral flattening and the development of a strong double
keel. However, it did not give rise to G. gansseri Bolli as
suggested by Pessagno (ibid.). R. subpennyi and G. gansseri
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 371
are phylogenetically independent. R. suwbpennyi evolved
from a double-keeled variant of R. rugosa whereas G.
_ gansseri evolved from a double-keeled variant of A. blowi
Pessagno, n. sp. (cf. Text-figure 35 and G. gansseri herein) .
Range.—G._ fornicata—stuartiformis assemblage zone,
R. subcircumnodifer subzone (R. subpennyi zonule) to
G. contusa—stuartiformis assemblage zone, G. gansseri sub-
zone, ? A. mayaroensis subzone.
Occurrence.—In the present study R. swbpennyi has
been observed in the Early Maestrichtian portion of the
Méndez shale and in the Middle Maestrichtian portion of
the Papagallos shale of Mexico.
In Texas it occurs in the Middle Maestrichtian (G.
ganssert subzone) Corsicana marl of Travis County.
In southwestern Arkansas it occurs in the Early Mae-
strichtian Saratoga chalk of Howard County.
This species is common in the Early Maestrichtian
portion of the Rio Yauco formation of Puerto Rico. It
also occurs in the Rio Blanco formation (cf. Pessagno 1960,
1962) .
R. subpennyi was originally described by Gandolfi
(1955) from the Colon formation of Colombia.
Family ABATHOMPHALIDAE Pessagno, new family
Type genus.—Abathomphalus Bolli, Loeblich, and
Tappan, 1957.
Definition.—Tests trochospiral, spiroconvex to bicon-
vex with or without a double or single keel. Chambers
spherical, ovoidal (compressed), or truncate; separated
by raised or depressed sutures. Umbilicus relatively small,
covered by tegilla having infralaminal accessory apertures,
but lacking intralaminal accessory apertures. Primary aper-
ture, interiomarginal, extraumbilical-umbilical in position.
Outer wall radial hyaline perforate to imperforate. Septal
walls and tegilla microgranular hyaline, finely perforate.
Remarks.—The Abathomphalidae differ from the Glo-
botruncanidae (1) by possessing primary apertures which
are extraumbilical-umbilical in position and (2) by pos-
sessing tegilla with only infralaminal accessory apertures.
They differ from the Marginotruncanidae Pessagno, n.
fam. in their possession of large, well-developed tegilla
rather than portici.
The Abathomphalidae may have been derived from
either the Globotruncanidae or the Rotaliporidae (Text-
figure 6). It is not likely that the Abathomphalidae
evolved from the Marginotruncanidae as this group was
extinct well before the time of the former group’s first
appearance in Late Campanian times.
It is likely that the early globigeriniform Aba-
thomphalidae like Globotruncanella evolved from either
globigeriniform Rotaliporidae like Hedbergella or from
globigeriniform Globotruncanidae like Archacoglobigerina.
The evolution of Globotruncanella from Hedbergella could
have been readily perpetuated through the enlargement of
the portici to form tegilla. The evolution of Globotrun-
canella from Archacoglobigerina would involve the shift
of the primary aperture to an extraumbilical-umbilical
position and the loss of intralaminal accessory apertures.
Inasmuch as the Rotaliporidae had greatly reduced breed-
ing populations by Campanian times, it seems more likely
to the writer that the Abathomphalidae evolved from the
rapidly evolving Globotruncanidae. Several Maestrichtian
species formerly placed in Hedbergella by various workers
can now be definitely placed in Globotruncanella. It ap-
pears unlikely that Hedbergella existed after Early Cam-
panian times.
Range.—G. fornicata—stuartiformis assemblage zone,
R. subcircumnodifer subzone to G. contusa—stuartiformis
assemblage zone, A mayaroensis subzone.
Occurrence.—Maestrichtian of Boreal, Austral, and
Tethyan faunal provinces.
Genus ABATHOMPHALUS Bolli, Loeblich, and Tappan, 1957
Type species.—Globotruncana mayaroensis Bolli, 1951.
Remarks.—The diagnosis of Loeblich and Tappan
(1964, p. C663) is generally accepted herein with the
following minor emendations: (1) The umbilicus does
not seem to be consistently covered by a single tegillum
as suggested by Loeblich and Tappan (ibid.). ‘Tegilla
extend out from each chamber as indicated by Cormin-
boeuf (1961, p. 115, pl. 1, figs. da-c). The specimen illus-
trated and described by Corminboeuf shows individual
tegilla with infralaminal accessory apertures. It is possible
that these tegilla become fused together in some individ-
uals to give the appearance of a single tegillum. It is also
possible that the specimen figured by Loeblich and ‘Tap-
pan (1964, fig. 529:5) is not so well preserved as that of
Corminboeuf. The single tegillum figured by these authors
is small and may only represent a tegillar extension from
one of the early chambers of the test. Tegilla from subse-
quent chambers may have been broken off during sample
preparation or during sedimentation. (2) The double keels
of Abathomphalus mayaroensis are entirely radial hyaline
imperforate and are not strengthened by ultragranular
hyaline imperforate accretions of material as is the case
with double-keeled species of Globotruncana. (3) Septal
372 PALAEONTOGRAPHICA AMERICANA (V, 37)
walls and tegilla are microgranular hyaline, finely per-
forate.
Loeblich and Tappan (1964, p. C662) correctly noted
the extraumbilical-umbilical position of the aperture of
Abathomphalus, but, nevertheless, included this genus in
the Globotruncanidae which they stated includes forms
with primary apertures in an umbilical position.
Range.—G. contusa—stuartiformis assemblage zone; A.
mayaroensis subzone.
Occurrence.—Late Maestrichtian of Boreal, ‘Tethyan,
and Austral faunal provinces.
Abathomphalus mayaroensis (Bolli)
Plate 92, figures 49; Plate 95, figure 5
1951. Globotruncana mayaroensis Bolli, Jour. Paleont., vol. 25, No. 2,
p- 198, pl. 35, figs. 10-12.
1953. Globotruncana mayaroensis Bolli, Subbotina, Trudy Vses. Neft.
Naukno.—Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 181,
pl. 8, figs. 2a-c.
1955. Globotruncana mayaroensis Bolli, Gandolfi, Bull. Amer. Paleont.,
vol. 36, No. 155, p. 18, pl. 1, figs. 2a-c.
1956. Rugotruncana mayaroensis (Bolli), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, pp. 553, 554, pl. 22, figs. 10-12.
1957. Globotruncana (Globotruncana) planata Edgell, Micropaleont.
vol. 3, No. 2, p. 115, pl. 4, figs. 7-9.
1957. Abathomphalus mayaroensis (Bolli), Bolli, Loeblich, and Tap-
pan, U.S. Nat. Mus., Bull., No. 215, p. 43, pl. 11 figs. la-c.
1961. Globotruncana mayaroensis Bolli, Corminboeuf, Eclogae Geol.
Helv., vol. 54, No. 1, pp. 114, 115, pl. 1, figs. 4a-c.
1962. Praeglobotruncana (P.) mayaroensis (Bolli), Berggren, Stock-
holm. Contr. Geol., vol. 9, No. 1, pp. 32-36, pl. 7, figs. 3a-c.
1964. Abathomphalus mayaroensis
529: no. 5.
Description.—Test trochospiral, somewhat spiroconyex,
truncated by wide, but weakly developed double keel;
spiral side mildly convex; umbilical side typically concave
with chambers sloping toward umbilicus. ‘Vest with three
well-developed whorls; earliest whorl showing Globotrun-
canella havanensis (Voorwijk) stage of development (PI.
95, fig. 5); four to six chambers in final whorl. Chambers
spirally with slightly arched roofs, petaloid in shape; sepa-
rated by straight, radial, depressed sutures. Umbilicus
shallow, covered by system of tegilla on well-preserved
specimens which display infralaminal, but not intralami-
nal accessory apertures insofar as known. Primary aperture
interiomarginal, extraumbilical in position. Outer wall
radial hyaline perforate except for keel and occasional
rugosities. Double keel entirely radial hyaline imperforate;
spiral and umbilical rims weakly developed, lacking accre-
tions of ultragranular hyaline, imperforate calcite. Beads
and rugosities ultragranular hyaline imperforate. Septal
walls and tegilla microgranular hyaline, sparsely perforate.
Remarks.—A mayaroensis is morphologically distinct
(Bolli) , Loeblich and ‘Tappan,
Treatise in Invert. Paleont., pt. C, Protista 2, vol. 2, p. C663, fig.
from double-keeled of Globotruncana both internally and
externally and bears no direct phylogenetic relationship
with these species. In thin-section it clearly shows a Globo-
truncanella havanensis (Voorwijk) stage of development
in its earliest whorls. As suggested by Bolli (1951, p. 198),
this species seems to have evolved from a G. citae Bolli
(= G. havanensis Voorwijk) ancestor.
The writer has examined the holotype of G. maya-
roensis Bolli in the collections of the U.S. National Mu-
seum, Washington, D.C. He has likewise examined and
thin-sectioned abundant topotypic specimens from the
Late Maestrichtian portion of the Guayaguayare forma-
tion of Trinidad.
Range.—G. contusa—stuartiformis assemblage zone;
A mayaroensis subzone. This planktonic species is one of
the most important guide fossils for recognizing Late
Maestrichtian deposits throughout the world.
Occurrence.—In the present study, A. mayaroensis was
noted only in the Late Maestrichtian portion of the
Méndez shale in the: Tampico area. ‘To date, it has not
been observed in surface outcrop anywhere in the Gulf
Coastal Plain and Atlantic Coastal Plain areas of the
United States.
In the West Indies A.
Late Maestrichtian Penalver formation
mayarocnsis was noted in the
(Habana group)
by Bronnimann and Rigassi (1963, p. 280). It was origi-
nally described by Bolli (1951, 198) from the Pointe-a-
Pierre Railway Cut marl member of the Guayaguayare
formation of ‘Trinidad. Elsewhere in the Western Hemi-
(1955,
p. 18) in the Maestrichtian Colon formation of Colombia.
sphere, this species has been noted by Gandolfi
In Eurasia A. mayaroensis species has been recorded
by Berggren (1962) from the Late Maestrichtian of Den-
mark; by Subbotina (1953), from the Late Maestrichtian of
Russia; by Sigal (1959) from the Maestrichtian of France,
by Bolli, Cita, and Schaub (1962) from the Late Maestrich-
tian of Italy; and by Corminboeuf (1961) from the Late
Maestrichtian of the “Préalpes Externes” of Switzerland.
Dalbiez (1955, p. 167) recorded but did not figure this
species from the Late Maestrichtian of Tunisia.
A. mayaroensis was figured by Edgell (1957, p. 115)
under the name of Globotruncana (G.) planata Edgell
from the Late Maestrichtian of Australia.
.
Genus GLOBOTRUNCANELLA Reiss, 1957 (emended herein)
Type species.—Globotruncana citae Bolli, 1951 (= Glo-
botruncana havanensis Voorwijk, 1937) .
1957. Globotruncanella Reiss, Contr. Cushman Found, Foram. Res.,
vol. 8, pt. 4, pp. 135, 136, text-fig. 5c.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 373
Emended definition—Test trochospiral, biconvex to
spiroconvex; lacking keels but sometimes with imperforate
peripheral bands. Chambers spherical to ovoidal, com-
pressed; separated by depressed, curved, nonbeaded sutures
both spirally and umbilically. Wall surface smooth to
hispid. Umbilicus covered by spiral system of tegilla with
infralaminal accessory apertures in well-preserved speci-
mens. Primary aperture interiomarginal, extraumbilical-
umbilical in position. Outer wall radial hyaline, perforate
except for fine spines which are ultragranular hyaline im-
perforate. Septal walls and tegilla microgranular hyaline,
finely perforate. .
Remarks.—Globotruncanella Reiss differs from Hed-
bergella Bronnimann and Brown by the development of
tegilla with infralaminal accessory apertures. The tegilla of
some specimens seem to be fused together to form a single
compound plate (cf. Loeblich and Tappan, 1964, p. C661,
fig. 529: 3a-c) .® As tegilla are only present in perfectly pre-
served material, many Maestrichtian species herein as-
signed to Globotruncanella were assigned by numerous
other workers to Hedbergella because tegilla could not be
observed. It is likely that tegilla will be found on well-
preserved specimens of Hedbergella homedelensis Olsson
and Hedbergella mattsoni (Pessagno) .
Globotruncanella Reiss gave rise to Abathomphalus
Bolli, Loeblich, and Tappan through the spiral-umbilical
compression of the test and the acquisition of a double-
keeled periphery.
Range.—G. fornicata—stuartiformis assemblage zone;
R. subcircumnodifer subzone to G. contusa—stuartiformis
assemblage zone, A. mayaroensis subzone insofar as known
from present data.
Occurrence.—World-wide; Boreal, Tethyan, and Aus-
tral faunal provinces.
Globotruncanella havanensis (Voorwijk)
Plate 84, figures 1-3
1937. Globotruncana havanensis Voorwijk, Kon. Akad. Wetensch.,
Proc., vol. 40, p. 195, pl. 1, figs. 25, 26, 29.
1943. Globorotalia sp. Van Wessem, Rijks.-Univ. Mededeel, Utrecht.
Geog., Geol. ser. 2, No. 5, p. 48, pl. 2, figs 3-4.
1946. Globorotalia pshadae Keller, Soc. Nat. Moscow, Bull., n. ser.,
vol. 51, No. 3, pp. 99, 108, pl. 2, figs. 4-6.
1951. Globotruncana citae Bolli, Jour. Paleont., vol. 25, No. 2, p. 197,
pl. 35, figs. 4-6.
1953. Globorotalia pshadae Keller, Subbotina, Trudy Vses. Neft.
Naukno. Issled. Geol.—Razved. Instit., n. ser., No. 76, p. 204,
pl. 16, figs. la-6c.
1954. Globotruncana citae Bolli, Ayala, Assoc. Méx. Petrol. Geol.,
Bol., vol. 6, p. 387, pl. 3, figs. 2a-c.
1954, Globotruncana havanensts Voorwijk, Ayala, Assoc. Méx. Petrol.
Geol., Bol., vol. 6, p. 396, pl. 6, figs. 2a-c.
1955. Globotruncana citae Bolli, Gandolfi, Bull. Amer. Paleont., vol.
36, No. 155, p. 51, pl. 3, figs. lla-c.
1955. ?Globotruncana (Rugoglobigerina) petaloidea subpetaloidea
Gandolfi, Bull. Amer. Paleont., vol. 36, No. 155, p. 52, pl. 3, figs.
12a-c.
1956. Rugotruncana havanensis (Voorwijk), Bronnimann and Brown,
Eclogae Geol. Helv., vol. 48, No. 2, p. 552, pl. 22, figs. 4-6; pl.
24, fig 5, (pt.), 10.
1956. Marginotruncana citae (Bolli), Hofker, Neues Jahrb. Geol.
Paleont., Abh. 103, p. 334, fig. 25.
1957. Globotruncanella citae (Bolli), Reiss, Contr. Cushman Found.
Foram. Res., vol. 8, pt. 4, pp. 135,136, text-fig. 5c.
1957. Globotruncana (Globotruncana) citae Bolli, Edgell, Micro-
paleont., vol 3, No 2, p. 111, pl. 1, figs. 13-15.
1960. Globotruncana (Rugotruncana) havanensis Voorwijk, Pessagno,
Micropaleont., vol. 6, No 1. p. 103.
1962. Praeglobotruncana havanensis (Voowijk), Berggren, Stockholm
Contr. Geol., vol. 9, No. 1, pp. 26-30, pl. 7, figs. la-c.
1963. Globotruncanella havanensis (Voorwijk), Bronnimann and
Rigassi, Eclogae Geol. Helv.. vol. 56, No. 1, pl. 17, figs. 2a-3e (no
pagination) .
1964. Globotruncana havanensis Voorwijk, Loeblich and Tappan,
Treatise on Invert. Paleont., pt. c, Protista 2, vol. 2, p. C662;
fig. 529, 3a-c.
Remarks.—Bronnimann and Brown (1956, p. 552)
noted that this species possesses long apertural flaps which
extend into the umbilicus and which in later chambers
form a protruded umbilical cover plate with accessory
apertures. Loeblich and Tappan (1964, fig. 529; 3a-c)
figured a Cuban specimen of G. havanensis (Voorwijk)
with an umbilical cover plate (fused tegilla ?) and with
infralaminal accessory apertures.” The extraumbilical posi-
tion of the primary aperture was noted by Bergeren (1962,
pp- 26-30) and various other workers. The writer finds
that specimens of Globotruncanella havanensis may either
possess or lack imperforate peripheral bands.
There seems little doubt that A. mayarocnsis (Boll)
evolved from a stock of Globotruncanella havanensis (Voor-
wijk) possessing imperforate peripheral bands as A. maya-
roensis possesses a suppressed G. havanensis early stage of
deveiopment (cf. Plate 95, figure 5).
Range.—G. fornicata—stuartiformis assemblage zone,
G. elevata subzone to G. contusa—stuartiformis assemblage
zone, A, mayaroensis subzone.
Occurrence.—In the present study this species is only
known from the Late Campanian to Late Maestrichtian
portions of the Méndez shale in the Tampico Embayment
area of Mexico.
Elsewhere in the Western Hemisphere it is known from
the Maestrichtian of Cuba, Puerto Rico, Trinidad, and
Colombia.
In Eurasia G. havanensis is known from the Maestrich-
tian of Denmark, Germany, Holland, and Russia. It is
also known from the Maestrichtian of Australia.
9T. Saito (Lamont Geol. Obsery.) recently sent the writer well-
preserved specimens of G. havanensis with a tegullum extending out
from each chamber in the last whorl.
374 PALAEONTOGRAPHICA AMERICANA (V, 37)
Globotruncanella monmouthensis (Olsson)
Plate 61, figures 1-3
1960. Globorotalia monmouthensis Olsson, Jour. Paleont., vol. 34, No.
1, p. 47, pl. 9, figs. 22-24.
1962. Praeglobotruncana (Hedbergella) monmouthensis (Olsson), Berg-
gren, Stockholm Contr. Geol., vol. 9, No. 1, pp. 37-40, pl. 8,
figs. la-3c; text-fig. 4; la-5e.
1964. Hedbergella monmouthensis
Nom2: pp» LOLs play ties. 3!
(Olsson), Micropaleont., vol. 10,
Remarks.—Globotruncanella monmouthensis (Olsson)
is characterized by its low trochispiral test with spherical
to subspherical chambers. Its chambers increase rapidly in
size, the later chambers tending to be less spherical. ‘The
umbilicus is small, deep, and round, Well-preserved speci-
mens from the Kemp clay and Corsicana marl possess
well-developed, fragile tegilla with infralaminal accessory
apertures. The primary aperture of G. monmouthensis is
a highly arched, rounded opening which is extraumbilical-
umbilical in position.
‘The observation of tegilla on specimens of this species
definitely places it within Globotruncanclla Reiss (see
emended definition herein) .
The writer examined the holotoype of G. monmouth-
ensis Olsson in the collections of the U.S. National Mu-
seum, Washington, D.C.
Range.—G. contusa—stuartiformis assemblage zone: G.
ganssert subzone insofar as known from this study. Berg-
gren (1962, pp. 18, 41) inferred that this species occurs
in the A. mayaroensis subzone in the Kjolby Gaard marl
of Jutland, Denmark.
Occurrence.—In the present study G. monmouthensis
was noted in the Corsicana marl of Navarro County, ‘Texas,
and in the Kemp clay of Falls County, Texas (see locali-
ties TX 284, 267-C, Appendix). The occurrence in the
Kemp clay is from a sample 20 feet below the Midway
(Kincaid) contact in a fauna which is assignable to the
upper part of the G. gansseri subzone. G. monmouthensis
has also been noted in the Arkadelphia marl of S.W.
Arkansas (AR 8, see Appendix) .
Olsson (1964, p. 161) noted that “A.
is restricted to the Redbank formation of New Jersey. The
Redbank formation seems to contain a planktonic assem-
monmouthensis”
blage that is assignable to the writer's G. contusa—stuarti-
formis assemblage zone, G. gansseri subzone.
As previously noted this species was noted and figured
by Berggren from the latest Maestrichtian of Denmark.
To date, G. monmouthensis (Olsson) is only known
from the Maestrichtian of the Boreal faunal province.
Globotruncanella petaloidea (Gandolfi)
Plate 82, figures 6-8, 9
1955. Globotruncana (Rugoglobigerina) petaloidea petaloidea Gan-
dolfi, Bull. Amer. Paleont., vol. 36, No. 155, p. 52, pl. 3, figs.
13a-c.
1960. Rugoglobigerina jerseyensis Olsson, Jour. Paleont., vol. 34, No.
1, p. 49, pl. 10, figs. 19,20.
1962. Praeglobotruncana (Hedbergella) petaloidea (Gandolfi), Berg-
gren, Stockholm Contr. Geol., vol. 9, No. 1, pp. 41-43, pl. 7, figs.
4da-c.
1962. Rugoglobigerina petaloidea petaloidea (Gandolfi), Herm, Bayer.
Akad. Wiss., Math.-Nat. KI., Abh. No. 104, p. 59, pl. 2, fig. 5.
1962. Rugoglobigerina jerseyensis Olsson, Jordan, Delaware Geol. Sur.,
Rept., No. 5, p. 7, pl. 2, figs. 2a-c.
1964. Praeglobotruncana petaloidea (Gandolfi) , Olsson, Micropaleont.,
vol. 10, No. 2, p. 162, pl. 1, figs. 6a-c, 7a-c; pl. 2, figs. la-c.
Remarks.—Globotruncanella petaloidea (Gandolfi) is
to Globotruncanella (Voorwijk). It
differs from this latter species by having much more
similar havanensis
inflated and spherical chambers. However, it is probable
that these species are closely related phylogenetically.
Gandolfi originally placed this species in Globotrun-
cana Cushman. Although it possesses tegilla, it cannot be
assigned to Globotruncana because of the extraumbilical-
umbilical position of its aperture. Rugoglobigerina jersey-
ensis Olsson is a junior synonym of G. (R.) petaloidea s.s.
Gandolfi. ‘The writer examined Gandolfi’s holotype (No.
20847) at the Paleontological Research Institution. Ithaca,
New York, and Olsson’s type specimens deposited at the
U.S. National Museum, Washington, D.C. Olsson (1960,
p. 49) noted the presence of tegilla extending across the
umbilicus of R. jerseyensis Olsson. In 1964, Olsson (pl. 1,
figs. 6a-c) figured a specimen of Globotruncanella peta-
(Gandolfi)
pletely across the umbilicus from the last chamber.
loidea showing a tegillum extending com-
Olsson (1964, p. 162) stated that he has observed an
this species
imperforate
peripheral bands are not uncommon among some speci-
imperforate peripheral band associated with
at high magnifications. As already noted,
mens of Globotruncanella havanensis (Voorwijk) .
Range.—G. fornicata—stuartiformis assemblage zone,
R. subcircumnodifer subzone to G. contusa—stuartiformis
assemblage zone: G. gansseri subzone to A. mayaroensis
subzone insofar as known from the present study. The
range zone presented in Text-fieure 5 should be corrected
for this species.
Occurrence.—In Mexico G. petaloidea (Gandolfi) has
been observed by the writer in Méndez strata assignable
to the A. mayaroensis subzone. In Texas G. petaloidea
(Gandolfi) occurs in the San Miguel formation of May-
GULE CRETACEOUS FORAMINIFERA: PESSAGNO 9
erick County, the Corsicana marl of Travis and Navarro
Counties, and the Kemp clay of Falls County.
Olsson (1964, p. 162) observed G. petaloidea in the
Marshalltown, Mt. Laurel, Navesink, and Redbank for-
mations of New Jersey.
Elsewhere in the Western Hemisphere, this species
has been recorded from the Colon formation of Colombia
by Gandolfi (1955).
Berggren (1962, p. 43) figured G. petaloidea (Gan-
dolfi) from the Kjolby Gaard marl of Jutland, Denmark.
The present data seem to indicate that G. petaloidea
is both a Boreal and Tethyan Maestrichtian species.
APPENDIX A
SAMPLE PREPARATION
Foraminiferal-bearing samples were prepared for ex-
amination through the utilization of the following combi-
nation of techniques:
Step A: Disintegration of samples—Crushed sample
(about 2 mm.-sized particles) is placed with water in a
Waring Blender. Mudstones or shales can be reduced to
mud in 30 to 60 seconds. The disintegrated material is
then wet sieved in a 230 mesh sieve to wash away the very
fine clay fraction.
Step B: Cleaning of microfossils—The sieved material
from the blender is then placed in an Acoustica (Model
DR 250 AH) ultrasonic cleaner for two or more hours.
Most or all of the matrix is cleaned from the fossils during
this time. The more indurated the sample the longer it
takes to clean matrix from the fossils. Samples are placed
in 1 quart jars filled with water and a small amount of
liquid detergent. The jars are placed in the cleaner tank
and the water level of the tank is adjusted so that three-
quarters of a given jar is submerged.
Step C: Concentration of microfossils—The sample
after being treated in the ultrasonic cleaner is wet sieved,
broken down into 230-80 mesh, 80-40 mesh, and 20-40 mesh
size fractions and dried in an oven.
If the sample contains a sparse microfauna, the 250-80
mesh and 80-40 mesh size fractions are placed in a Franz
Isoldynamic Separator. Foraminifera, Radiolaria, and ostra-
cods are concentrated in the nonmagnetic fraction whereas
clay particles are drawn via the magnetic properties of the
clay minerals into the magnetic fraction. Often a pure sep-
arate of Radiolaria and Foraminifera can be obtained
utilizing this last technique. (See Eckert, Hay, et al., 1961,
pp. 876, 877). Furthermore, samples which would other-
~I
ar |
wise be too sparsely fossiliferous to yield biostratigraphic
data, yield valuable information utilizing this technique.
Such a method of sample preparation has saved the
writer a great deal of valuable time in processing numerous
Upper Cretaceous samples from the Gulf Coast Region.
The Waring Blender allows almost total disintegration of
samples from indurated lithic units such as the Méndez
shale and the Austin chalk. Much of the material cleaned
by the ultrasonic cleaner is perfectly preserved and matrix
free. Planktonic specimens from the Kemp clay and “Upper
‘Taylor marl’, for example, often show delicate spines and
tegilla still intact.
ILLUSTRATION OF SPECIMENS
Specimens were illustrated with a Leitz stereoscopic
microscope equipped with a Zeiss Drawing Apparatus.
Photographs of sectioned specimens were made using a
Leitz Aristophot apparatus and a petrographic micro-
scope. Pictures with dark field illumination were made
with a Leitz phase contrast attachment.
LOCATION AND DESCRIPTION OF MICROFOSSIL SAMPLES
MENTIONED IN TEXT
The list of sample localities presented below includes
microfossil samples collected in Mexico, Texas, Arkansas,
and Puerto Rico. Mexican samples are prefixed by MX;
Texas samples by TX; Arkansas samples by AR; and
Puerto Rican samples by PR. Type localities of important
species are prefixed by TYPE.
A complete listing of fossiliferous samples collected
during this study will be cited in a second publication
dealing with the Upper Cretaceous stratigraphy per se.
Mexican localities are largely based on the surveyed
positions of kilometer posts along highways.
MEXICO
TYPE 1. Type locality of Globotruncana arca (Cush-
man) and Globotruncana conica White. Méndez. shale.
Buff calcareous siltstone rich in planktonic Foraminifera
collected in road cut about 2.2 kilometers east of Tamuin
(=Guerrero) , San Luis Potosi, Mexico, and immediately
east of bridge crossing of Tampico—Ciudad Valles Highway
(Rt. 110) over Rio Huiches at Huiches; several hundred
feet west of kilometer post K101.00.
TYPE 2. Type locality of Globotruncana contusa (Cush-
man). Méndez shale. Gray calcareous siltstone. Coco Sta-
tion. Kilometer post K574.00 on railroad from Tampico to
Ciudad Valles,
7 OF
370 PALAEONTOGRAPHICA AMERICANA (V, 37
DY PERSE dayne ventricosa
White. Méndez shale. Cream-colored calcareous mudstone
breaking with concoidal fracture. This locality corresponds
closely with that designated by White (1928, p. 182) as the
type locality of G. ventricosa (about 2.0 kilometers north-
east of village of Barranco on road between Majuel and AI-
dama). Sample collected at base of north bank of Arroyo
Pedregoso about 75 yards north of road (Text-figure 62) .
locality of Globotruncana
Bridge crossing of Manuel—Aldama road; about 1.29 kilom-
eters from Barranco and 23.5 kilometers from the inter-
section with the Tampico—Ciudad Mante Road.
White's locality was apparently located on an older,
now abandoned road, between Gonzalez and Barranco.
Remnants of an old bridge abutment of this road are
present where the new road crosses Arroyo Pedgregoso.
MX 5. Mendez shale. Cream-colored calcareous mudstone
breaking with concoidal fracture. Sample collected from
ditch exposure on west side of ‘Tampico—Ciudad Mante
Highway at kilometer post reading: K77:645.
MX 10. Méndez shale. Cream-colored mudstone breaking
with concoidal fracture; from ditch exposure on east side
of ‘Tampico—Ciudad Mante Highway; kilometer post read-
ing: K71.806.
MX 14. Méndez shale. Buff calcareous mudstones break-
ing with concoidal fracture. Tampico—Ciudad Mante High-
way. Kilometer post reading: K52.322. Hacienda Margina-
ritas.
MX 15. Méndez shale. Red to cream-colored calcareous
siltstones exposed on north side of Tampico—Ciudad Mante
Highway. Rancho Elfaisar near kilometer post K51.00 and
relatively near contact with Velasco.
MX 23. Méndez shale. Buff calcareous siltstone. Kilometer
post K96.00 on ‘Tampico—Ciudad Valles Highway (Rt.
110). Somewhat east of Rio Huiches bridge and Ranchito
Huiches.
MX 69. San Felipe formation. Buff to gray marls inter-
e@ buff. Mexico
D.F.—Nuevo Laredo Highway (Rt. 85).
reading: K538.034; southwest flank of Sierra del Abra;
northeast of Antiguo Morelos.
bedded with gray calcilutites weathering
Kilometer post
MX 78. Méndez shale. Red calcareous mudstone breaking
with concoidal fracture. Majuel—Aldama Road; 4.5 miles
(7.2 kilometers) from intersection with Tampico—Ciudad
Mante Highway; near site where Manuel—Aldama road
crosses south fork of Arroyo Pedregoso (Text-figure 62).
MX 79. Méndez shale. Cream-colored calcareous mud-
stone breaking with concoidal fracture. Mafuel—Aldama
Road; 6.4 miles (10.4 kilometers) from intersection with
Tampico—Ciudad Mante Highway (Text figure 62).
TEXT-FIGURE 62:
ot Aldama
Scale:
1 inch = about 12.5 kilometers
Key:
Ey Velasco
Km Mendez
K sf San Felipe
MX 82. Méndez shale. Cream-colored calcareous mud-
stone breaking with concoidal fracture. Mafuel—Aldama
Road; 5.5 miles (8.8 kilometers) from intersection with
Tampico—Ciudad Mante Highway (Text-figure 62).
MX 80. Méndez shale. Cream-colored calcareous mud-
stone breaking with concoidal fracture. Manuel—Aldama
Road; 10.045 miles (16.70 kilometers) from Tampico—
Ciudad Mante Highway; 2.089 miles (3.34 kilometers)
from Barranco.
MX 87. Méndez shale. Dark gray to brown indurated,
calcareous mudstones breaking with concoidal fracture.
0.398 miles (0.624 kilometers) west from intersection be-
tween Antiguo Morelos Road (Rt. 80) and Mexico, D.F.—
Nuevo Laredo Highway (Rt. 85). West side of Antiguo
Morelos,
MX 102. San Felipe formation. Gray, thin-bedded calici-
lutites and interbedded marls. Road (Rt. 80) between
Antiguo Morelos, Tamaulipas and Ciudad del Maijz, San
Luis Potosi; 6.63 miles (10.6 kilometers) west of intersec-
tion between Route 85 and Route 80 in Antiguo Morelos.
MX 110. San Felipe formation. Buff marls interbedded
with thin-bedded, gray calcilutites weathering buff. Pere-
grina Canyon, northwest of Ciudad Victoria (cf. Text-
figures 1-2); bank exposure north of Peregrina Canyon
Road and irrigation canal; 0.59 miles (0.62 kilometers)
west of Liberdad on Peregrina Canyon Road.
MX 126-151. Measured section of San Felipe formation
(1075 feet) in Boca Canyon. Buff marls, dark gray calci-
lutites, and chalks gradational into Agua Nueva forma-
GULE CRETACEOUS FORAMINIFERA: PESSAGNO
tion below and Méndez shale above. San Felipe exposed
along dirt road to Boca Canyon Dam; San Felipe—Agua
Nueva contact exposed at dam site (see Congreso Geologica
Internat., 20th Sesion, Mexico, 1956; Excursions A-l4 y
C-6; Guidebook: pp. 50-51, figure 5). Boca Canyon is situ-
ated southeast of Monterrey and northeast of the village
of Santiago along Mexico, D.F.-Nueyo Laredo Highway
(Rt. 85). A more detailed discussion of this important
section will be presented elsewhere. Localities referred to
in text are cited below:
MX 126. Basal-most San Felipe at contact with underlying
Agua Nueva formation (cf. Text-figure 2). Contact grada-
tional; San Felipe formation separated from Agua Nueva
formation at this locality by the first appearance of marl or
chalky layers. Gray calcilutites weathering buff with in-
terbedded marls and chalks. Limestone varying between
several inches and several feet in thickness. (Rotalipora
assemblage zone; R. cushmani-greenhornensis subzone.)
MX 128. 48 feet above base of San Felipe. Same lithology;
same age as MX 126.
MX 129. 112 feet above base of San Felipe. Same lithology;
same age as MX 128.
MX 130. 137 feet above base of San Felipe. Same lithol-
ogy. (Approximate contact between Rotalipora assemblage
zone and M. helvetica assemblage zone. M. helvetica assem-
blage zone, M. sigali subzone, containing reworked species
from underlying Rotalipora assemblage zone) .
MX 133. 204 feet above base of San Felipe. Same lithology
(M. helvetica assemblage zone, M. sigali subzone) .
MX 141. 439 feet above base of San Felipe formation.
Same lithology and same age as previous locality.
MX 142. 464 feet above base of San Felipe. Same lithology
and same age as previous locality.
MX 143. 489 feet above base of San Felipe. Same lithol-
ogy and same age as previous locality.
MX 144. 629 feet above base of San Felipe formation.
Same lithology (M. helvetica assemblage zone, IW. archaco-
cretacea subzone) .
MX 146. 683 feet above base of San Felipe formation.
Same lithology. Same age as noted for MX 144.
MX 147. 727 feet above base of San Felipe. Same lithology
(M. renzi assemblage zone) .
MX 148-151. 774 feet to 1075 feet. Same lithology. (G.
bulloides Assemblage zone, M. concavata subzone.)
MX 156. San Felipe formation. Buff marls interbedded
with gray calcilutites weathering buff; N45E; 8° SE.
Mamulique Pass. Kilometer post reading: K1030.839 on
Mexico, D.F.—Nuevo Laredo Highway (Rt. 85).
MX 157. San Felipe formation. Buff marl interbedded
with gray calcilutites weathering buff; N35E; 15° SE.
Mamulique Pass; kilometer post reading: K1047.678 on
Mexico, D.F.—Nuevo Laredo Highway (Rt. 85) .
MX 173. Papagallos shale. Dark gray calcareous mudstones
resembling those of Corsicana marl of Central Texas.
Mexico, D.F.—Nuevo Laredo Highway (Rt. 85) north
of Mamulique Pass. Outcrop near road. Kilometer post
reading: K1166.034.
MX 174.
from auger hole near mapped Upper Cretaceous—Lower
Tertiary contact. Low lying hill east of Mexico, D.F.—
Nuevo Laredo Highway (Rt. 85); near road entrances
to Ranchos Santa Celia and La Esparanza. Kilometer post
reading: K1174.57.
MX 206. Méndez shale. Red calcareous mudstones. Type
locality of Méndez shale; 300 meters east of Méndez Sta-
tion; kilometer post 629.3 on the railroad between ‘Tampico
and Ciudad Valles. (Sample from W. Storrs Cole, Cornell
Univ.) .
Papagallos shale. Buff calcareous mudstones
TEXAS
Rio Grande Area
RIO GRANDE AREA
TX 5. Eagle Ford group, Chispa Summit formation.
Chispa Summit, western Jeff Davis County. Thin-bedded
calcilutites and interbedded marls about 50 feet above
contact with underlying Buda limestone; west of locality
2660 of Adkins (1931, p. 39). About 0.25 miles east of
abandoned railroad cut (now a dirt road); | airline mile
N60E of Needle Peak and 4.75 airline miles N67E of town
of Chispa (see U.S.G.S. Chispa Sheet, 1892). Rotalipora
assemblage zone; R. cushmani—greenhornensis subzone) .
TX 19. Grayson formation (= Del Rio clay). Light gray
claystone; 17.5 feet above contact with underlying George-
town. Evans Creek, Val Verde County; 0.8 airline miles,
N85W of bridge crossing of U.S. Route 90 bridge over
creek. Route 90 bridge over Evans Creek is 26.6 miles
from Pecos River Bridge (Rt. 90) and 2.8 miles from
Devil’s River Bridge (Rt. 90). U.S. Army Corps of Engi-
neers, Feely Quadrangle (15’) .
TX 25-35. Eagle Ford group (Boquillas formation undif-
ferentiated) ; 112 foot exposure showing gradational con-
tact between Upper Eagle Ford and basal part of Austin
chalk (“Atco” member of Durham, MS. (1957). Sycamore
Creek; Val Verde—Kinney County line; south bank of
horseshoe-shaped meander which is convex to south; 1.2
airline miles N52W of Sycamore Ranch House; 3.3 miles
due west of Rio Grande and international boundary.
U.S.G.S. Sycamore Ranch Quadrangle (15’).
378 PALAKONTOGRAPHICA AMERICANA (V, 37)
Locality mentioned herein: TX 30. Eagle Ford group.
3uff calcareous siltstone; 61.5 feet above level of pond in
creek bed (M. helvetica assemblage zone; W. archacocre-
tacea subzone) .
TX 36-41. Austin chalk. [‘“Atco’” member of Durham,
MS. (1957) ] Massive chalks and interbedded marls; 0.50
miles downstream (due south) from Route 277 (85) bridge
over Pinto Creek. U.S. Army Corps of Engineers, ‘Teques-
quite Creek Quadrangle (15’). Kinney County.
Samples mentioned herein: TX 36. Marl collected 3 feet
above creek level. TX 40. Marlstone partings collected 43
feet above creek level.
TX 55. Austin chalk [“Atco’”” member of Durham, MS.
(1957) |. Interbedded chalks and marlstones 1 to 2.5 feet
thick in an exposure of 20.5 feet. Sample collected on south
bank of Cow Creek (Kinney County) immediately down
stream from Rt. 277 (85) bridge crossing; 10.5 feet above
level of creek. U.S. Army Corps of Engineers, Tequesquite
Creek Quadrangle (15’).
TX 60 A-C. Upson Clay (lower part). Greenish gray
calcareous mudstones weathering brown. Low lying hills;
0.40 airline miles east of Farm Road 1908; 2.0 airline miles
NI1E of intersection between irrigation canal and Farm
Road 1908; 0.8 airline miles N30W northwest of M. Wipf
Ranch, Maverick County. U.S. Army Corps of Engineers,
Quemado Sheet (15’).
TX 61. Upson clay (lower part). Greenish gray calcare-
ous mudstones weathering brown. Road cut (near wind-
mill) on Farm Road 1908; 6.8 miles down road from its
intersection with Route 277; 3.5 miles northeast of inter-
section between Farm Road 1908 and _ irrigation ditch.
U.S. Army Corps of Engineers, Tequesquite Creek Quad-
rangle (15’); Maverick County.
TX 75. Escondido formation (lower part). Bluff to south
of Eagle Pass—Indio Highway; intersection of Austin and
Cooledge Streets in Eagle Pass, Maverick County. About
60.5 feet of exposure. Sample TX 75 collected at base of
bluff; consisting of buff calcareous mudstone. U.S. Army
Corps of Engineers, Eagle Pass Quadrangle (15’) ;
ick County.
TX 89. Escondido formation (middle part). Dark gray
calcareous mudstone; 1.6 miles SI5E of F. Dolch Ranch;
3.1 miles S45W of Wiff Farm; about 0.9 miles west of
Central Power and Light Company power line. U.S. Army
Corps of Engineers, Eagle Pass Quadrangle (15’); Mav-
erick County.
Maver-
Austin area
Austin area
TYPE 5: Grayson formation (= Del Rio clay) exposed
on Shoal Creek just south of 34th Street Bridge, Austin,
Travis County. Type locality of Hedbergella delrioensis
(Carsey) , Praeglobotruncana bronnimanni Pessagno, n. sp.,
Pracglobotruncana delrioensis (Plummer), and Hedberg-
ella washitensis (Carsey). Samples mentioned herein:
TYPE 5-A. Cream-colored calcareous mudstone collected
20 feet above level of Shoal Creek. TYPE 5-B. Same lithol-
ogy. 25 feet above level of Shoal Creek. TYPE 5-C. Same
lithology; 30 feet above level of Shoal Creek. TYPE 5-D.
Same lithology; 40 feet above level of Shoal Creek and
5 to 7 feet below contact with Buda limestone (Buda
somewhat slumped at this locality) .
TYPE 6: Upper ‘Taylor marl member of Taylor forma-
tion exposed on Onion Creek (south bank); bluffs 0.4
miles due west of Moores Crossing; U.S.G.S. Montopolis
Quadrangle (15’). Type locality of Globotruncana forni-
cata Plummer and Globotruncana rosetta (Carsey). Sam-
ples noted herein: ‘TYPE 6-A. Gray calcareous mudstone
at level of Onion Creek. TYPE 6-B. Same lithology; 10
feet above level of creek. TYPE 6-C. Same lithology; 20
feet above level of creek. TYPE 6-D. Gray calcareous mud-
stone weathering buff; 35 feet above level of creek and
about 7 feet from top of bluff.
TX 103-108: Disconformable contact between Eagle Ford
group (South Bosque formation) and Austin chalk [“Atco”
member of Durham, MS. (1957) ]. Measured section at
Bouldin Creek east of Mary Street; about 280 yards down
Missouri Pacific Railroad tracks east of Mary Street Cross-
ing; Austin, Travis County; U.S.G.S. Austin West Quad-
rangle (7.5’). Samples mentioned herein: TX 105. South
Bosque formation. Black calcareous shale; 12 feet above
level of Bouldin Creek. TX 107. Top of South Bosque
formation. Buff marlstones with borings from overlying
Austin chalk; immediately below ‘‘Adkin’s condensed
zone’.
TX 128. Austin chalk. Burditt marl member. Buff marl
containing Exogyra ponderosa Roemer; 15 feet above the
contact between Dessau chalk member and Burditt marl
member; 34 feet above creek level. Little Walnut Creek,
0.16 miles upstream from bridge crossing of U.S. 290; 0.32
miles south, southeast of Travis County Dump; U.S.G.S.
Austin East Quadrangle (7.5’).
TX 157-161: Taylor formation (“Upper Taylor marl” mem-
ber) Gray to buff calcareous mudstones; 50 feet of expo-
sure. Webberville Road (Farm Road 969); 1300 feet west
of entrance to Travis State Schoo] (Farm Colony) . Samples
collected from ditch on north side of road. U.S.G.S. Austin
Quadrangle (15’). Samples noted herein: TX 157 collected
at base of ditch exposure; TX 158, 5 feet above TX 157;
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 379
TX 159, 30 feet above TX 157; TX 160, 5 feet above
TX 159; TX 161, 10 feet above TX 160.
TX 169-184: Corsicana marl. Dark gray to buff calcareous
mudstones. Measured section (97 feet) just upstream
(north) of Route 71 bridge crossing over Onion Creek,
Travis County. U.S.G.S. Montopolis Quadrangle (15’).
TX 169. Dark gray mudstone collected 5 feet above creek
level. TX 173. Dark gray mudstones collected 29.5 feet
above level of creek. Common Exogyra costata Say. TX 183.
Buff mudstone at 85 feet above creek level.
TX 185-189. Kemp clay. Bluffs on south side of Colorado
River; 2.0 airline miles N20E of Garfield Cemetery; 2.2 air-
line miles S30W of Webberville. Greenish gray, glauco-
nitic, calcareous mudstones containg Exogyra costata Say,
Turritella sp., and other megafossils. Samples mentioned
herein: TX 186. 30 feet above level of Colorado River.
Waco area
TX 190. Upper Mainstreet formation exposed on Middle
Bosque River, upstream from bridge crossing of county
road; 0.6 miles northwest of Liberty Hill, McLennan
County. White nodular limestone beds with gray to light
brown fissile shale partings; 11.5 feet above creek level;
8 feet below Mainstreet—Grayson (= Del Rio) contact
(Baylor Geological Society, 1958, Stop 8, pl. 8).
TX 193-197. Measured section of upper part of Grayson
formation (= Del Rio clay); 35 feet of upper Grayson
exposed along a tributary of the South Bosque River, ap-
proximately 0.9 miles east of Farm Road 2416 and 2.1 miles
northwest of Spring Valley, McLennan County. (Baylor
Geological Society, 1958, Stop 9, pl. 9). Localities men-
tioned herein: TX 195. Light gray calcareous mudstones
at creek level; 55 feet below Grayson—Pepper shale con-
tact. TX 195. Light gray calcareous mudstone containing
minute pelecypods; 20 feet above creek level; 15 feet below
Grayson—Pepper shale contact.
TX 220-229. Austin chalk [“Atco” member of Durham,
MS. (1957) ]. Measured sectioned (136 feet) at Lover's
Leap; Cameron Park, Waco, McLennan County. U.S.G.S.
Waco East Quadrangle (7.5’). Samples mentioned herein:
TX 226: White marlstones interbedded with massive chalks;
107’ above Bosque River. TX 228. White platy chalk or
marlstone; 126 feet above Bosque River.
TX 237-243. Austin chalk [“Bruceville’” member of Dur-
ham, MS (1957) ]. Measured section (49 feet). Gray marl-
stones and interbedded chalks with marlstones predomi-
nating. White Rock Creek; exposure about 0.3 miles south-
east of bridge crossing of road between Farm Road 933 and
town of Elm Mott. U.S.G.S Elm Mott Quadrangle (7.5’).
Sample mentioned herein: TX 242. Gray marlstone 41
feet above level of White Rock Creek: upper part of
Austin chalk near contact with Lower Taylor marl.
TX 244-254. Taylor formation (“Lower Taylor marl” mem-
ber) ; 77.5 feet of buff to gray calcareous mudstones break-
ing with concoidal fracture. Exposure on south bank of
Tradinghouse Creek, McLennan County; 1.5 miles west
of juncture between Tradinghouse Creek and Tehuacana
Creek; | airline mile S68E of Harrison Switch (large mean-
der in Tradinghouse Creek) ; 0.2 miles due south of county
road bridge over Tradinghouse Creek. Waco East Quad-
rangle (7.5’). Localities mentioned herein: TX 244. Dark
gray calcareous mudstone; 3.5 feet above creek. TX 245.
Same lithology; 8.5 feet above creek. TX 251: Buff cal-
careous mudstone; 43.5 feet above creek. TX 252. Buff
calcareous mudstone; 53.5 feet above creek.
TX 255 A-B. Taylor formation (Wolfe City sand mem-
ber). Silty, buff-colored marls exposed on tributary of
Tradinghouse Creek immediately north of county road;
1.8 airline miles N31E of Hallsburg and 1.1 airline miles
S24W of west end of New Lake Mart; McLennan County.
TX 256 A-TX 258. Measured section of top of Wolfe
City sand and lower part of Pecan Gap chalk; 0.8 airline
miles east of juncture between State Highway 6 and Farm
Road 2307; southeast of Perry, Falls County. Samples men-
tioned herein: TX 256 A. Wolfe City sand. Silty marl 1
foot below contact with Pecan Gap chalk. TX 256 B.
Pecan Gap chalk immediately above contact. TX 257.
Pecan Gap chalk 7 feet above Wolfe City—Pecan Gap
contact; platy chalk. TX 258. Same lithology; 9 feet above
contact.
TX 267 A-C; TX 268, TX 269, TX 270: Kemp clay.
Greenish gray, calcareous, glauconitic mudstones. Farm
Road 413 Bridge over Brazos River; 2.4 airline miles south-
east of Highland, Falls County; 2 airline miles north
of point where Brazos River enters Milam County from
Falls County. TX 267 A-C: Samples collected along east
bank of river immediately north of bridge. Sample TX
267 A colected at river level; TX 267 B collected 2.5 feet
above TX 267 A; TX 267 C collected 2 feet above
TX 267 B. All 3 samples from an horizon approximately
20 feet below Kemp Clay—Kincaid (Midway) contact.
TX 268-270: Kemp clay—Kincaid (Midway) contact ex-
posed 0.5 airline miles downstream (south) from Farm
Road 413 bridge on west side of Brazos River. TX 268.
River level; 6 feet below Kemp—Kincaid contact. TX 269.
3 feet above river; 3 feet below Kemp Clay—Kincaid
(Midway) contact. TX 270. Immediately below Kemp
Clay—Kincaid contact.
TX 281-287. Measured section (39.5 feet) of Corsicana
580) PALAKONTOGRAPLICA AMERICANA (V,
marl. “Old Corsicana Clay Pit’; 2.0 miles south of Court-
house in Corsicana, Navarro County; off Farm Road 709
(15th Street); dark gray to buff colored calcareous mud-
stone breaking with concoidal fracture. Localities men-
tioned herein: TX 281. Base of quarry as of 1962; dark
eray, calcareous mudstone with Baculites. TX 284. Dark
gray to buff mudstone; 15 feet above quarry floor.
TX 291 A-C. Taylor formation (“Upper Taylor marl”
member). Buff, calcareous mudstones breaking with con-
coidal fracture; collected from ditch crossing State Route
73; 2.4 miles east of intersection of Route 73 with Farm
Road 737 in town of Prairie Hill, Limestone County.
Samples collected at one foot intervals in exposure of
several feet.
TX 344-363. Socony Mobil Oil Co., Field Research Lab.,
Atco Core of Eagle Ford group (see Brown and Pierce,
1962, pp. 2133-2147). Core taken at Atco Cement plant
(Corehole No. 18), Atco, McLennan County. Samples
mentioned herein: TX 353. Lower part of South Bosque
formation; sample from 156 feet; brownish-gray, fissile,
laminated shale. TX 357. Upper part of Lake Waco for-
mation; sample from 200 feet; brown to gray-brown fis-
sile, calcareous, laminated shale.
Dallas area
TX 300-342; 402-417. Socony Mobil Oil Co., Field Re-
search Lab., Dallas Core of type Eagle Ford (see Brown
and Pierce, 1962, pp. 2133-2147). “5.2 miles south of the
old Eagle Ford Station on the Texas Pacific Railroad;
3.5 miles south of Arcadia Park; 10 miles north-northwest
of Britton and 12.5 miles southeast of the old Tarrant
Station on the St. Louis, San Francisco, and Texas Rail-
road.” Samples mentioned herein: ‘TX 311. Lower part
of Arcadia Park formation, Gray calcareous, fissile shale
at 201 feet. TX 312. Britton formation; dark gray to
brown, calcareous, fissile shale at 211 feet. TX 329. Brit-
ton formation; dark gray to brown, calcareous, fissile, shale
at 404 feet. TX 5330. Britton formation; dark gray to
brown, calcareous, fissile shale at 414 feet. TX 335. Brit-
ton formation; dark gray to brown, calcareous, fissile
shale at 444 feet. TX 335. Britton formation; dark gray
to brown calcareous, fissile, shale at 464 feet. TX 338.
Britton formation; dark gray to brown, calcareous, fissile
shale at 494 feet.
TX 375-382. Taylor formation (“Lower Taylor marl” mem-
ber). Clay pit of Baron Brick Company at Palmer, Ellis
County; 38 feet of section sampled. Gray to buff, calcare-
ous, mudstones with concoidal fracture. Samples men-
tioned herein: TX 375. Base of clay pit as of 1962.
O-1. Austin chalk. [“Bruceville’ member of Durham MS
Ta
37)
(1957) ] from J. Hazel, U.S. Geological Survey, Washing-
ton, D.C. 1.6 miles east of Garland Courthouse on State
Highway 7; downstream fifty yards from the crossing of
a small tributary to a large branch of Rowlett Creek. Blue
marl below last good chalk.
L-I. Austin chalk [“Bruceville’” member of Durham, MS.
(1957) ] from J. Hazel, U.S. Geological Survey, Wash-
ington, D.C.) 1.2 miles southwest of Rockett (northern
Ellis County) on State Highway 813; 25 yards downstream
from crossing of small tributary of Red Oak Creek; 30
feet of section exposed; sample four feet below discon-
formable contact (erosional break) with overlying “Lower
‘Taylor marl”, This sample is important because it is of
Early ‘Taylorian age. It contains G. stuartiformis Dalbiez
and other Taylorian or Campanian species plus reworked
Santonian species such as Marginotruncana concavata
(Brotzen). The four foot interval of the Austin chalk
below this erosional break probably was reworked by
worms and other burrowing organisms during Early Tay-
lorian times.
SOUTHWESTERN ARKANSAS
AR 1-6. White Cliffs Landing of Little River, Sevier Coun-
ty. Exposure of upper part of Ozan formation and 87 feet
of Annona chalk. Locality mentioned herein: AR 6: 82 feet
above Annona—Ozan contact.
AR 7A. Lower part of Brownstown marl. Dark gray
mudstone breaking with concoidal fracture; containing
common Exogyra ponderosa Roemer. 1.7 miles west of
Brownstown on Brownstown—Ben Lommond Road, Sevier
County.
AR 8. Arkadelphia marl. Buff marlstones. 2.6 miles north
of Fulton on Route 355; 0.8 miles from McNab; road
between Fulton and McNab, Hempstead County. Sample
from ditch west of road.
AR 11. Marlbrook marl. Gray calcareous mudstone break-
ing with concoidal fracture exposed in road cut of State
Route 355. 0.6 miles north of Saratoga; 0. 25 miles south
of power line crossing road; 0.5 miles south of turnoff to
Okay and Ideal Cement Company Plant, Howard County.
AR 18. Arkadelphia marl. Buff marlstone; 3 miles west
of Prescott, Nevada County on State Route 24. Auger
hole in ditch. .
PUERTO RICO
PR 789.00. Rio Yauco formation; see Pessagno (1960,
p. 88, text-fig. 1).
PR 789.32. Rio Yauco formation; see Pessagno (1960,
p. 88, text-fig. 1).
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 381
MISCELLANEOUS
G-9. Upper Campanian of Bavaria from W. W. Hay. Rail-
road cut 350 meters south of Eisenaerat. Contains G.
ventricosa White and G. calcarata Cushman.
G-19. Marl of Late Coniacian to Early Santonian age from
the Lower Gosau. Sample collected by Dr. W. W. Hay from
an outcrop of marl beside a trail that crosses the Edlbach
(=Edelbach). Gosautal, Edelbachgraben, Austria. Local-
ity G-19 is about 250 meters S77E of Auer and N61W of
the western part of Ramsau. This is the type locality of
the neotype selected herein for Rosalina canaliculata Reuss.
It is also the type locality of Marginotruncana pseudolin-
neiana Pessagno, n. sp. (See map; Text-figure 63) .
C-52. “Neylandville marl”; see Cushman (1946, p. 3).
From W. Berggren.
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Brandmirt ~
+H— = 250 meters
Gosau Sheet 95/4
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PLATES
388
Figure
1 ,2,3-5.
a
7-8,9.
10-11
12,13.
17-19.
14,16,20.
15.
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 48
TX 312. Eagle Ford group (Britton formation), ‘This seems to be a transitional
form between H. delrioensis (Carsey) and 1. hessi (Pessagno). Rudimentary supple-
mentary sutural apertures are present; 100 s<¢.
Page
Hedbergella delrioensis (Carsey) 282
TYPE 5B. Grayson formation; topotypes; 100.
. Schackoina cenomana_ (Schacko) 279
TX 329. Eagle Ford group (Britton formation); 200x.
Heterohelix sp. cf. H. moremani (Cushman) 260
TX 329. Eagle Ford group (Britton formation); 216 x.
Heterohelix moremani (Cushman) 260
TX 329. Eagle Ford group (Britton formation); 216.
Guembilitria harrisi Tappan 258
TX 329. Eagle Ford group (Britton formation); 206.
Loeblichella hessi (Pessagno) 288
TX 312. Eagle Ford group (Britton formation), Note sutural supplementary aper-
tures on spiral side of test; 100%.
Loeblichella coarctata (Bolli) 288
TX 312. Eagle Ford group (Britton formation); 100.
Loeblichella sp. 288
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 48
Plate 49
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 49
Figure
1. Hedbergella washiltensis (Carsey)
TX 190. Washita group (Mainstreet formation); 62.5><.
2-3. Globigerinelloides caseyi (Bolli, Loeblich, and Tappan)
TX 333. Eagle Ford group (Britton formation); 216 ><
4-5. Globigerinelloides caseyi (Bolli, Loeblich, and Tappan)
TX 329. Eagle Ford group (Britton formation); 2165.
6-8. Praeglobotruncana bronnimanni, n. sp.
TYPE 5-B. Washita group (Grayson formation); holotype; 100.
9-10. Praeglobotruncana bronnimanni, n. sp.
TX 195. Washita group (Grayson formation). Paratype. 1445.
11. Praeglobotruncana bronnimanni, n. sp.
TX 19. Washita group (Grayson formation); Paratype; 100.
12-14. Rotalipora evoluta Sigal
Type 5-B. Washita group (Grayson formation); 100 <.
286
286
294
389
390
Figure
1,2,4-6.
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 50
Page
Rotalipora appenninica (O. Renz) 289
MX 156. San Felipe formation; 62.5%.
. Rotalipora greenhornensis (Morrow) 295
MX 156. San Felipe formation; 62.5X.
. Hedbergella (?) mattsoni (Pessagno) ye 283
TX 291-A. Taylor formation (“Upper Taylor marl” member); 144.
Praeglobotruncana slephani (Gandolfi) 287
TX 417. Eagle Ford group (Britton formation); 44x.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 50
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 51
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 51
Figure Page
1. Hedbergella planispira (Tappan) . 283
TX 311. Eagle Ford group (Britton formation); 72x.
2-4. Whiteinella archacocretacea, n. gen., n. sp. 298
TX 105. Eagle Ford group (South Bosque formation); Paratype; 72x.
5. Hastigerinoides watersi (Cushman) 274
USNM, Holotype; Austin chalk; 72>.
6. Rotalipora cushmani (Morrow) 292
TX 5. Eagle Ford group (Chispa Summit formation); 72x.
7-9. Rotalipora cushmani (Morrow) 292
TX 333. Eagle Ford group (Britton formation); 72x.
10-12. Rolalipora appenninica (O. Renz) 289
MX 156. San Felipe formation; 72x.
13-14,18. Rotalipora greenhornensis (Morrow) 295
TX 5. Eagle Ford group (Chispa Summit formation); 72x.
15-17,19-21. Rotalipora greenhornensis (Morrow) 295
MX 156. San Felipe formation; 72x.
391
392 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 52
Figure Page
1-2. Clavihedbergella simplex (Morrow) 285
TX 330. Eagle Ford group (Britton formation); 216.
3-5. Praeglobotruncana delrioensis (Plummer) a... 286
TX 194. Washita group (Grayson formation); 216 x.
6-8. Hedbergella amabilis Loeblich and Tappan 281
TX 338. Eagle Ford group (Britton formation); 100 x.
9-11,12. Hedbergella brittonensis Loeblich and Tappan 282
TX 335. Eagle Ford group (Britton formation); 100.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 52
Plate 53
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-2;3-4.
6-8.
5
9-10,11-12,13.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 53
Hedbergella planispira (Tappan)
TX 311. Eagle Ford group (Britton formation); 144><.
Rotalipora evoluta Sigal
TX 193. Washita group (Grayson formation); 144.
. Clavihedbergella moremani (Cushman)
USNM, Holotype; Eagle Ford group; 216 >.
Margintruncana helvetica (Bolli)
MX 142. San Felipe formation; 62.5.
Page
283
595
394 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 54
Figure Page
1-3. Marginotruncana helvetica (Bolli) se walls)
TX 105. Eagle Ford group (South Bosque formation); 50x.
4-6. Marginotruncana sigali (Reichel) °3 = .. 313
MX 142. San Felipe formation; 50x.
7-9,10-12,16-18. Marginotruncana marginata (Reuss) 307
TX 105. Eagle Ford group (South Bosque formation); 72x.
19-21,22-24,25. Whiteinella archaeocretacea, n. sp. a seas é
TX 105. Eagle Ford group (South Bosque formation). Figures 19-21, 25 =
paratypes; figures 22-24 = holotype. Note slightly extraumbilical position of
primary aperture; 72x.
13-15. Marginotruncana bouldinensis, n. sp. 301
TX 105. Eagle Ford group (South Bosque formation); holotype; 72x.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 54
Plate 55
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 55
Figure
1-2. Clavihedbergella moremani (Cushman)
TX 330. Eagle Ford group (Britton formation); 100x.
3,8-10. Marginotruncana indica (Jacob and Sastry) .....
TX 353. Eagle Ford group (South Bosque formation); 100.
4-7. Marginotruncana renzi (Gandolfi) ae
TX 353. Eagle Ford group (South Bosque formation); 100).
395
396 PALAKONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 56
Figure Page
1-3. Marginolruncana sigali (Reichel) 313
TX 353. Eagle Ford group (South Bosque Formation); 117 x.
4-6,7-9. Marginotruncana bouldinensis, n. sp. : 301
TX 353. Eagle Ford group (South Bosque formation); paratypes; 117.
10-12. Marginotruncana marginata (Reuss) : 307
TX 353. Eagle Ford group (South Bosque formation); 117 x.
Plate 56
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 57
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 57
Figure
1-2. Marginotruncana sigali (Reichel)
TX 105. Eagle Ford group (South Bosque formation); 117%.
3-5. Marginotruncana imbricata (Mornod)
MX 142. San Felipe formation; 117X.
6-9. Marginotruncana indica (Jacob and Sastry) ....
Page
315
306
307
TX 353. Eagle Ford group (South Bosque formation). Note infralaminal accessory aper-
tures bordering portici; 117.
397
398 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 58
Figure Page
1-2. Marginotruncana concavata (Brotzen) : ; peeene .. 304
TX 228. Austin chalk (‘“Atco” member); 72x.
3-6,7-9. Marginotruncana concavata (Brotzen) 304
TX 242. Austin chalk (‘“Bruceville’ member); 144 x.
Plate 58
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 59
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 59
Figure Page
1-3,4,8-10. Archaeoglobigerina blowi, n. sp. 316
TX 252. Taylor formation (“Lower Taylor marl’ member); paratypes; 114.
5-7. Archaeoglobigerina blowi, n. sp. : 316
TX 252. Taylor formation (“Lower Taylor marl” member); holotype; 114).
399
400
Figure
1.
no
oo
4-5.
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 60
Schackoina multispinata (Cushman and Wickenden)
MX 80. Méndez shale; 216%.
. Globigerinelloides prairiehillensis, n. sp.
TX 244. Taylor formation (“Lower Taylor marl” member); 144.
Globigerinelloides asperus (Ehrenberg) Boaonse tenes eres
TX 128. Austin chalk (Burditt marl member); hypotype; 216x.
. Hastigerinoides alexanderi (Cushman) ceernaael
USNM (Cushman Collection No. 15750); holotype; Austin chalk; 144».
-9. Archaeoglobigerina bosquensis, n. sp.
TX 226. Austin chalk (“Atco” member); paratype; 144.
Archaeoglobigerina bosquensis, n. sp.
TX 226. Austin chalk (“Atco” member); holotype; 144.
Plate 60
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 61
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 401
EXPLANATION OF PLATE 61
Figure Page
1-3. Globotruncanella monmouthensis (Olsson) 374
TX 284. Corsicana marl; 144%.
4-5. Loeblichella coarctata (Bolli) 288
AR 7A. Brownstown marl; 144%.
6-8,9-11. Loeblichella hesst (Pessagno) 288
AR 7A. Brownstown marl; 144».
402
Figure
1-3,6-8. Loeblichella coarctata (Bolli)
AR 7A. Brownstown marl; 144.
4. Globotruncanella sp. aff. G. monmouthensis (Olsson)
TX 267-C. Kemp clay; 144 x.
5. Globigerinelloides bolli, n. sp. eee recep
TX 291-C. Taylor formation (“Upper Taylor marl’ member); paratype; 100).
9. Globigerinelloides volutus (White) (=messinae s.s. (Bronnimann)
MX 78. Méndez shale; 144~%.
10-11. Globigerinelloides volutus (White) (= messinae s.s. (Bronnimann)
TX 281. Navarro group (Corsicana clay); 144.
12,13. Globigerinelloides subcarinatus (Bronnimann)
MX 10. Méndez shale; 216 <.
14-16. Rugotruncana subcircumnodifer (Gandolfi)
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 62
MX 173. Méndez shale; 144.
Page
288
Plate 62
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 63
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 403
EXPLANATION OF PLATE 63
Figure Page
1-2. Globotruncana fornicata Plummer Fr 338
TYPE 6-C. Taylor formation (“Upper Taylor marl” member); topotypes; 62.5 <.
3.4-6,7-9. Globotruncana fornicata Plummer
338
TX 245. Taylor formation (“Lower Taylor marl’ member); fig. 6 oversized due
to illustration error; 62.5>¢.
104
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 64
Figure Page
1-3. Rugoglobigerina tradinghousensis, n. sp. 367
TX 246. Taylor formation (“Lower Taylor marl” member); holotype; 108 x.
4,5,6-8. Rugoglobigerina tradinghousensis, n. sp. 367
TX 246. Taylor formation (“Lower Taylor marl’ member); paratypes; 108 x.
9-11. Globotruncana hilli, n. sp. 343
PX 291-C. Taylor formation (“Upper Taylor marl” member); holotype; 108 x.
12-14,21-23. Globotruncana hilli, n. sp. 343
TX 291-C. Taylor formation (Upper Taylor marl member); paratypes; 108.
15-17. Globotruncana bulloides Vogler soot $24
TX 291-C. Taylor formation (“Upper ‘Taylor marl” member). Gerontic form
similar to G. culverensis Barr; 50%.
18-19. Globolruncana calcarata Cushman 326
TX 291-C. Taylor formation (‘Upper ‘Taylor marl” member); 665.
20. Globotruncana calcarata Cushman 326
MX 87. Méndez shale; 665<.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 64
Plate 65
PALAEONTOGRAPHICA AMERICANA, VOL. V
co
--
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 65
Figure
1-3,4. Rugoglobigerina rotundata Bronnimann
ro
MX 174. Papagallos shale; 72x.
5-6,7. Rugoglobigerina reicheli Bronnimann
AR 8. Arkadelphia marl; 72x.
8-10. Globotruncana conica White
TYPE 1. Méndez shale; topotype; 72x.
11-13. Marginotruncana coronata (Boll)
G-19. Lower Gosau beds; Gosautal, Edelbachgraben, Austria; 72><.
14-16. Marginotruncana angusticarenata (Gandolfi)
TX 40. Austin chalk (‘“Atco” member); 72%.
17-19. Marginotruncana angusticarenala (Gandolf)
TX 107. Eagle Ford group (South Bosque formation); 72x.
20-23. Marginotruncana renzi (Gandolfi)
TX 55. Austin chalk (“Atco” member); 72.
24-27. Marginotruncana pseudolinneiana, n. sp.
G-19. Lower Gosau beds; Gosautal, Edelbachgraben, Austria; holotype; 72x.
300
300
310
310
405
406 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 66
Figure Page
1-2. Rugoglobigerina macrocephala Bronnimann : : Wena ena eeaece tee 366
TX 281. Navarro group (Corsicana marl); 144.
3-4,5,6-8. Globotruncana plummerae Gandolfi 35]
TX 291-B. Taylor formation (“Upper Taylor marl” member); 100.
Plate 66
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 67
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 67
Figure
1-3. Globotruncana bulloides Vogler
TX 256-A. Taylor formation (Wolfe City sand member); 144%.
4-6,7-9. Globotruncana nothi (Bronnimann and Brown)
TX 291-B. Taylor formation (“Upper Taylor marl” member); 144.
Page
. 324
350
107
408
PALAFONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 68
Figure
1-3. Rugoglobigerina rotundata Bronnimann
MX 174. Papagallos shale; 144.
4,5. Pseudoguembelina excolata (Cushman)
TX 281. Navarro group (Corsicana clay); 144.
6-8. Globotruncana nothi (Bronnimann and Brown)
TX 291-B. Taylor formation (“Upper Taylor marl” member); 144.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 68
Plate 69
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 69
Figure Page
1-3,7. Globotruncana stephensoni, n. sp. 354
TX 291-B. Taylor formation (“Upper Taylor marl” member); paratypes; 144s.
4-6. Globotruncana stephensoni, n. sp. 354
TX 291-B. Taylor formation (“Upper Taylor marl” member); holotype; 144%.
109
110
Figure
1,2.
3-5,6-8.
9-12.
PALAKONTOGRAPHIGA AMERICANA (V, 37)
EXPLANATION OF PLATE 70
Globigerinelloides multispina (Lalicker)
TX 281. Navarro group (Corsicana clay); 100%.
Archaeoglobigerina cretacea (d’Orbigny)
TX 255-A. Taylor formation (Wolfe City sand member); 100.
Globotruncana rosetta (Carsey)
TX 291-A. Taylor formation (“Upper Taylor marl” member);
Plate 70
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 71
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 71
Figure Page
1-2. Hastigerinoides watersi (Cushman) 27
274
TX 244. Immature specimen lacking bulbus chamber tips. Taylor formation
(“Lower Taylor marl” member); 100.
3-5. Whiteinella inornata (Bolli) 299
TX 351. Eagle Ford group (South Bosque formation); 100%.
6-8,9-11,12-13. Globotruncana lapparenti (Brotzen) 344
TX 246. Taylor formation (“Lower Taylor marl” member); 100.
411
4]2 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 72
Figure Page
1-2,3-4,7-9. Globolruncana linneiana (d’Orbigny) eo LO
TYPE 4. Méndez shale; 100.
5-6. Globotruncana calcarata Cushman 5 Sate . 326
TX 291-C. Taylor formation (“Upper Taylor marl” member); 62.5 x.
Plate 72
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 73
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 73
Figure Page
1-4. Globotruncana loeblichi, n. sp. . 349
TX 375. Taylor formation (“Lower Taylor marl” member); holotype; 144 x.
5-8. Globotruncana rosetta (Carsey)
: : 352
USNM (Cushman Collection). Ripley formation; holotype of G. cretacea Cushman and
G. marei Banner and Blow; 144~.
9-10. Globotruncana bulloides Vogler 324
TX 256-A. Taylor formation (Wolfe City sand member); 144.
413
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 74
Figure Page
1-3. Margintotruncana pseudolinneiana, n. sp. Bee eee LO
PR 789.32. Rio Yauco formation (Puerto Rico); 81s.
4. Rugoglobigerina hexacamerata Bronnimann 364
MX 174. Papagallos shale; 100.
5-8. Marginotruncana canaliculata (Reuss) 302
9-11,12-14.
G-19. Lower Gosau beds, Edelbachgraben, Austria. Neotype selected herein for
Rosalina canaliculata Reuss, 1854; 1445.
Rugoglobigerina scotti (Bronnimann) 367
MX 174. Papagallos shale; 144 ><.
Plate 74
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 75
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 415
EXPLANATION OF PLATE 75
Figure Page
1. Globotruncana gansseri Bolli ache 341
TX 281. Navarro group (Corsicana marl); 50>.
2-3. Rugoglobigerina rugosa (Plummer) . 366
MX 174. Papagallos shale; 54>.
4-5,6-8. Globotruncana bulloides Vogler : : : 366
TX 291-A. Taylor formation (“Upper Taylor marl” member); 54x.
9-10,27. Globigerinelloides yaucoensis (Pessagno) 279
TX 291-A. Taylor formation (“Upper Taylor marl” member); 50>.
ll. Gublerina robusta de Klasz 265
TX 281. Navarro group (Corsicana marl); 50>.
12-14,15-17 Pseudotextularia elegans s.l. (Rzehak) 268
MX 5. Méndez shale; 50><.
18-20. Globotruncana contusa s.l. (Cushman) 330
TX 281. Navarro group (Corsicana marl); 50x.
21-24. Globotruncana ventricosa White 362
TX 291-A. Taylor formation (“Upper Taylor marl” member); 50>.
25-26. Globotruncana ventricosa White 362
TYPE 4. Méndez shale; topotype; 54%.
116 PALAFONTOGRAPHICA AMERICANA (V, 57)
EXPLANATION OF PLATE 76
Figure Page
1-3. Marginoltruncana pseudolinneiana, n. sp. Eee .. 310
G-19, Lower Gosau; Austria; paratype; 144 x.
4-6. Rugoglobigerina scotti (Bronnimann) 367
MX 174. Papagallos shale; 144.
7-9. Loeblichella coarctata (Bolli) eect 288
TX 281. Navarro group (Corsicana marl); 144.
10-11. Globigerinelloides bentonensis (Morrow) 275
MX 156. San Felipe formation; 144.
12-14. Rugolruncana subpennyi (Gandolfi) 370
PR 789.32. Rio Yauco formation; Puerto Rico; 82>.
Plate 76
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 77 |
= |
:
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 77
Figure
1-3. Rugolruncana subcircumnodifer (Gandolfi)
TX 281. Navarro group (Corsicana marl); 100x.
4-6,7-9. Globotruncana contusa s.s._ (Cushman)
MX 79. Méndez shale; 62.5.
Page
369
330
118
Figure
6-8,9-11.
12-14.
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 78
. Pseudoguembelina palpebra Bronnimann
TX 267-C. Navarro group (Kemp clay); 100s.
. Heterohelix striata (Ehrenberg) :
TX 244. Taylor formation (“Lower Taylor marl’ member); 72x.
Globotruncana contusa s.s. (Cushman) .
MN 5. Méndez shale; 62.5%.
Globotruncana elevata (Brotzen) ;
TX 291-C. Taylor formation (“Upper ‘Vaylor marl” member); 64x.
Page
267
264
330
336
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 78
Plate 79
PALAEONTOGRAPHICA AMERICANA, VOL. V
<
.
.
>
.
=
t
So
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 79
Figure
1. Pseudoguembelina costulata (Cushman)
MX 5. Méndez shale; 100%.
2-4. Globotruncana aegyptiaca Nakkady
MX 174. Papagallos shale; 144.
5,6-8. Globotruncana arca (Cushman)
5. MX 5. Méndez shale; 62.5.
6-8. MX 79. Méndez shale; 72%.
9-10,11-12. Globotruncana ventricosa White
TYPE 4. Méndez shale; topotypes; 62.5 <.
13-14. Globotruncana ventricosa White
MX 82. Méndez shale; 62.5.
Page
266
319
321
362
362
419
120 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 80
Figure Page
1-2. Globotruncana elevata (Brotzen) 336
MX 8. Méndez shale; 62.5x.
3-6. Globotruncana stuartiformis Dalbiez transitional to Globotruncana elevata (Brotzen) 336,337
TX 157. Taylor formation (“Upper Taylor marl” member). Note that the last two
chambers of the final whorl are G. elevata-like both in terms of their shape spirally
and their keel angles; 62.5.
7-9. Globotruncana fornicata Plummer 338
TX 242. Austin chalk (“Bruceville’ member); 144.
Plate 80
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 81
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1-3.
4-6.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 81
Page
Globotruncana stuarti (de Lapparent) 356
Guayaguayare formation of Trinidad (Ad. mayaroensis subzone); 67.5%.
Globotruncana stuarti (de Lapparent) : 356
MX 174. Papagallos shale; 62.5%.
. Globigerinelloides bollii n. sp. : Rae : 275
TX 291-C. Taylor formation (“Upper Taylor marl” member); holotype; 100.
Globotruncana elevata (Brotzen) 336
MX 5. Méndez shale; 62.5%.
. Globotruncana elevata (Brotzen) 336
MX 80. Méndez shale; 62.5%.
99
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 82
Figure Page
1-2,3-5. Globotruncana conica White 328
MX 174. Papagallos shale; 72x.
6-8,9. Hedbergella petaloidea (Gandolfi) 374
PX 281. Navarro group (Corsicana marl); 72%.
10-11. Globigerinelloides multispina (Lalicker) 276
TX 291-C. Taylor formation (“Upper ‘Vaylor marl” member); 1005¢. Figure 11, some
what greater than 100%.
12-15. Globotruncana austinensis Gandolfi 323
TX 291-C. Taylor formation (“Upper Taylor marl” member); 100 <.
Plate 82
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 83
PALAEONTOGRAPHICA AMERICANA, VOL. V
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 83
Figure
1. Globigerinelloides prairiehillensis, n. sp.
TX 291-C. ‘Taylor formation (“Upper Taylor marl’ member); paratype; 1005.
2-7. Globotruncana duwi Nakkady
TX 267-C. and TX 268. Navarro group (Kemp clay); 100.
8-10. Globotruncana aegyptiaca s.s. Nakkady
TX 267-C and TX 268. Navarro group
(Kemp clay);
D,-D’,/D,-D’, =
2.5;
100%.
124
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 84
Figure
1-3. Globotruncanella havanensis (Voorwijk)
MX 78. Méndez shale; 144 x.
4-6,10-12. Globotruncana trinidadensis Gandolfi
TX 281. Navarro group (Corsicana marl); 144.
7-9. Globotruncana trinidadensis Gandolfi
MX 174. Papagallos shale; 144.
Plate 84
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 85
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 85
ligure Page
-2,3-4,5-6,7-8,9. Helerohelix reussi (Cushman) 263
TX 353. Eagle Ford group (South Bosque formation); 216.
10-11. Pseudotextularia elegans (Rzehak) s.s. 268
TX 246. Taylor formation (“Lower Taylor marl” member); 100 <.
125
426 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 86
Figure Page
1-2. Helerohelix reussi (Cushman) 263
USNM (Cushman Collection ); holotype; Austin chalk; 144%.
8-4. Heterohelix planata (Cushman) 262
USNM (Cushman Collection); holotype; Taylor formation (“Upper Taylor marl” mem-
ber; 144™.
5-6. Heterohelix globocarinata (Cushman) 259
USNM (Cushman Collection); holotype; Taylor formation (“Upper Taylor marl” mem-
ber); 144~x.
7-8. Heterohelix punctulata (Cushman) 262
MX 80. Méndez shale; 144.
9-10. Heterohelix punctulata (Cushman) 262
USNM (Cushman Collection); holotype; Taylor formation (“Upper Taylor marl” mem-
ber); 144~.
11. Pseudotextularia intermedia. de Klasz 269
MX 78. Méndez shale; 144%.
Plate 86
PALAEONTOGRAPHICA AMERICANA, VOL. V
Plate 87
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
1,2,3.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 87
Guembelitria cretacea Cushman .
TX 183. Navarro group (Corsicana marl); 216%.
. Heterohelix pulchra (Brotzen)
TX 291-A. Taylor formation (“Upper Taylor marl” member); 144.
. Heterohelix globulosa (Ehrenberg)
TX 255-A. Taylor formation (Wolfe City sand member); 100.
Planoglobulina carseyae (Plummer)
TX 281. Navarro group (Corsicana marl); 100 x.
. Planoglobulina acervulinoides (Egger)
MX 174. Papagallos shale; 100 x.
. Planoglobulina carseyae (Plummer)
MX 174. Papagallos shale; 100>.
427
428 PALAKONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 88
Figure Page
1-2,10-11. Helerohelix glabrans (Cushman) .. 259
TX 281. Navarro group (Corsicana marl); 100%.
3-4,5. Heterohelix striata (Ehrenberg) 264
TX 244. Taylor formation (‘Lower Taylor marl” member); 72>.
6-7. Helerohelix striata (Ehrenberg) 264
TX 244. Taylor formation (“Lower Taylor marl” member); 144 <.
8-9. Pseudoguembelina costulata (Cushman) 266
TX 283. Navarro group (Corsicana marl); 2106x.
12,13,17. Planoglobulina glabrata (Cushman) 272
TX 244, Taylor formation (“Lower Taylor marl” member); 100><.
14-16. Pseudotextularia elegans s.s. (Rzehak) 268
TX 246. Taylor formation (“Lower Taylor marl” member); LOO.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 88
ND
0)
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nye OSs sits yi bert
Ne Gives genie
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 89
ait)
Wi |
(eo cage
.O
(nh
Vi
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PEATE 89
Figure Page
1-2. Helerohelix moremani (Cushman) 261
USNM (Cushman Collection); holotype; Eagle Ford group; 100%.
3-4. Pseudoguembelina palpebra Bronnimann and Brown 267
MX 174. Papagallos shale; 144.
5,12-14. Pseudoguembelina sp. aff. P. Palpebra 267
MX 174. Papagallos shale: 144.
6-7. Heterohelix planata (Cushman) 262
TX 281. Navarro group (Corsicana marl). Note accessory apertures; 216.
8-9. Heterohelix navarroensis Loeblich 261
TX 283. Navarro group (Corsicana marl); 216).
10-11. Pseudotextularia elegans s.s. (Rzehak) 268
TX 244. Taylor formation (“Lower Taylor marl” member); 100.
15. Planoglobulina multicamerata (de Klasz) 972
MX 80. Méndez shale; 100%.
429
430 PALAKONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 90
Figure Page
1-24. Globigerinelloides praiviehillensis, n. sp. 277
TX 291-C. Taylor formation (“Upper Vaylor marl” member). 1-2 = holotype;
4 = paratype; 100%.
3. Pseudoguembelina costulata (Cushman) 266
PR 789.32. Rio Yauco formation; Puerto Rico; 90>.
5. Pseudoguembelina excolata (Cushman) 267
TX 267-A. Navarro group (Kemp clay); 100%.
6-8. Globotruncana arca (Cushman) 359
MX 79. Méndez shale; 62.5.
9-10. Globotruncana trinidadensis Gandolfi 359
MX 78. Méndez shale; 62.5.
11-13. Globotruncana sp. cf. G. trinidadensis Gandolfi 2 359
MX 78. Méndez shale; 62.5><.
14-15. Racemiguembelina fructicosa (Egger) 2°70
TX 267-B. Navarro group (Kemp clay); 100><.
16. Pseudotextularia deformis (Kikoine) s./. 269
TX 267-B. Navarro group (Kemp clay); 100%.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 90
Plate 91
PALAEONTOGRAPHICA AMERICANA, VOL. V
Figure
or
~
8,11,12-15.
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 91
Page
-2. Globigerinelloides multispina (Lalicker) .......... 276
TX 291-A. Taylor formation (“Upper Taylor marl’? member); 144.
. Rugoglobigerina reicheli Bronnimann 365
MX 174. Papagallos shale; 144).
. Rugotruncana subpennyi (Gandolh) : 370
MX 5. Méndez shale; 144%.
- Rugoglobigerina hexacamerata Bronnimann 364
AR 8. Navarro group (Arkadelphia marl); 144.
Rugotruncana subpennyi (Gandolfi) 370
TX 173. Navarro group (Corsicana marl); 144%.
43]
432 PAl.AEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 92
Figure Page
1-3. Globotruncana stuartiformis Dalbiez 357
MX 5. Méndez shale; 54>.
4-6,7-9. Abathomphalus mayaroensis (Bolli) 372
MX 78. Méndez shale; 54%.
10-12. Globotruncana contusa (Cushman) s:s. 330
MX 79. Méndez shale; 54>
13-15,16-18. Globotruncana gansseri Bolli 341
TX 281. Navarro group (Corsicana marl); figs. 14, 16 undersized due to illustrat-
ing error; 50x.
19-21. Pseudotextularia deformis (Kikoine) s.s. 269
MX 174. Papagallos shale; 54>.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 92
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 93
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 93
Figure
1-5,8.
9-11.
12,13:
Globotruncana elevata (Brotzen)
1. PE 653. TX 291-C. Taylor formation (“Upper Taylor marl’ member); vertical sec-
tion; 100. 2. PE 658. TX 291-C. Taylor formation (“Upper Taylor marl” member);
vertical section; 100. 3. PE 652. TX 291-C. Taylor formation (“Upper Taylor marl”
member); vertical section; 100. 4. PE 645. TX 291-C. Taylor formation (“Upper
Taylor marl’ member); vertical section; 84.3. 5. PE 659. TX 291-C. Taylor forma-
tion (“Upper Taylor marl member); horizontal section; 120.55. 8. PE 671. TX 157.
Taylor formation (“Upper Taylor marl’? member); vertical section; 100.
7. Globotruncana stuartiformis Dalbiez
6. PE 672. TX 157. Taylor formation (“Upper Taylor marl” member); vertical section;
100. 7. PE 670. MX 80. Méndez shale; vertical section; 100).
Globotruncana stuarti (de Lapparent)
9. PE 732. TX 268. Navarro group (Kemp clay). Note spines in posterior keel region.
Vertical section; 100 ¢. 10. PE 684. MX 174. Papagallos shale; vertical section; 100s.
11. PE 675. MX 174. Papagallos shale; vertical section; 100.
Globotruncana conica White
12. PE 623-b. MX 174. Papagallos shale; vertical section; 1005. 13. PE 630. MX 78.
Méndez shale; vertical section; 100 >¢.
. Globotruncana calcarata Cushman
PE 657. TX 291-B. Taylor formation (“Upper Taylor marl” member); vertical section;
117.5.
Page
336
328
326
434 PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 94
(ALL photos with dark field illuminated)
Figure Page
1. Globotruncana hilli, n. sp. 343
PE 942. TX 291-C. Taylor formation (“Upper Taylor marl’ member); paratype; half sec-
tion showing spiral side of test; 100.
2,3. Archaeoglobigerina blowi, n. sp. 316
2. PE 1021. TX 252. Taylor formation (“Lower ‘Vaylor marl” member); vertical section
of a paratype. 100%. 3. PE 1019. TX 252. Taylor formation (“Lower ‘Vaylor marl”
member); half section showing spiral side of test; paratype; 100.
4,5. Archaeoglobigerina cretacea (d’Orbigny) 317
4. PE 125. TX 291-C. Taylor formation (“Upper Taylor marl” member); vertical section;
1009¢. 5. PE 1028. TX 291-C. Taylor formation (“Upper Taylor marl” member); half
section showing spiral side of test. 100.
6. Globotruncana aegyptiaca s.s. Nakkady 319
PE 710. TX 267-C. Navarro group (Kemp clay); vertical section; 100><.
7. Globotruncana stuarti: (de Lapparent) $56
PE 732. TX 268. Navarro group (Kemp clay); vertical section; 170%.
8. Globotruncana calcarata Cushman 326
PE 649. TX 291-C. ‘Taylor formation (“Upper ‘Faylor marl’ member), Half section
shows spiral side of test; note tublospines in next to last whorl; LOOX.
9. Globotruncana austinensis Gandolfi 323
PE 863. TX 291-C. Taylor formation (“Upper Taylor marl” member); vertical section.
Note depressed spiral surface of early whorls; 176.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 94
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 95
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 45
EXPLANATION OF PLATE 95
Figure Page
1-4. Globotruncana gansseri Bolli 341
1.PE 697. TX 281. Navarro group (Corsicana marl); horizontal section; 1185. 2. PE
699. TX 281. Navarro group (Corsicana marl); vertical section; 1005. 3. PE 698.
TX 281. Navarro group (Corsicana marl); vertical section; 100... 4. PE 690. TX 281.
Navarro group (Corsicana marl); vertical section; 100.
cu
- Abathomphalus mayaroensis (Bolli) 372
PE 757. MX 78. Méndez shale. Note Globotruncanella havanensis stage; vertical sec-
tion; 100s.
6,7. Marginotruncana concavata (Brotzen) 304
6. PE 1038. L-l. Austin chalk (‘Hutchins chalk’’ member); vertical section; 100 ><.
7. PE 837. Upper Cretaceous of Tunisia (from Sigal via H. Bolli); vertical section;
100. .
8-9. Globotruncana aegypliaca s.s. Nakkady 319
8. PE 716. TX 267-C. Navarro group (Kemp clay) vertical section; 1005. 9. PE 705.
TX 267-A. Navarro group (Kemp clay) (D,-D’,/D,-D’, = 2.5 mm.); horizontal (half)
section; 118.
10,11. Globotruncana ventricosa White 362
10. PE 830. TYPE 4. Méndez shale; topotype; vertical section 100%. 11. PE 812. TX
291-B. Taylor formation (“Upper Taylor nrarl’” member); vertical section 115.3.
12-14. Globotruncana duwi Nakkady 333
12. PE 715. TX 267-C. Navarro group (Kemp clay); vertical section; 2605. 13. PE
715. Same specimen as shown in 12. Enlargement of tegillum showing pores and micro-
granular wall structure; 582>¢<. 14 PE 715. Same specimen as shown in 12. Enlargement
showing double keel, canaliculate radial hyaline wall, and ultragranular hyaline spines.
Note pore cutting otherwise imperforate keel. Double keel structure radial hyaline,
imperforate in part and ultragranular hyaline. imperforate in part (cf. Text-figure 40,
variety of TYPE 2); 582x.
136
Figure
eae
7,8,17.
=)
11,13-16.
PALAEKONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 96
Page
. Globotruncana trinidadensis Gandolfi 359
1. PE 729. TX 268. Navarro group (Kemp clay); vertical section; 1005. 2. PE 968.
TX 267-C. Navarro group (Kemp clay); vertical section; 100 <.
Globotruncana fornicata Plummer 338
3. PE 762. TYPE 6-D. Taylor formation (“Upper Taylor marl” member); topotype
vertical section; 100%. 4. PE 769. TX 252. Taylor formation (“Lower Taylor marl”
member); vertical section; 100%.
3. Globotruncana stephensoni, n. sp. 354
5. PE 792. TX 291-A. Taylor formation (“Upper Taylor marl” member); paratype;
vertical section; 1009¢. 6. PE 793. TX 291-A. Taylor formation (“Upper Taylor marl”
member); paratype; vertical section; 100.
Globotruncana arca (Cushman) 321
7. PE 881. TX 291-A. Taylor formation (“Upper Taylor marl” member); vertical sec-
tion; 1005¢. 8. PE 805. TX 291-A. Taylor formation (“Upper Taylor marl” member);
vertical section; 100%. 17. PE 805. Enlargement of double keel: a = radial hyaline
imperforate; b = ultragranular hyaline imperforate; 190.
. Globotruncana plummerae Gandolfi . 351
PE 785. AR Il. Marlbrook marl; vertical section; 100%.
. Globotruncana nothi (Bronnimann and Brown) 350
PE 790. TX 291-B. Taylor formation (“Upper Taylor marl’ member); vertical sec-
tion; 100%.
Globotruncana contusa (Cushman) ; 330
11. PE 748. TX 281. Navarro group (Corsicana marl) ( = G. contusa s.l.); vertical
section; 100). 13. PE 737. TX 281. Navarro group (Corsicana marl). (= G. contusa
s.l.); vertical section; 100. 14. PE 738. TX 281. Navarro group (Corsicana marl).
(= G. contusa s.s.); vertical section; 1005. 15. PE 750. MX 78. Méndez shale;
— G. contusa s.s.); 100%. 16. PE 753. MX 78. Méndez shale; (= contusa s.s.);
116~x.
. Globotruncana sp. cf. G. contusa (Cushman) 351
PE 736. TX 281. Navarro group (Corsicana marl); vertical section; 100 <¢.
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 96
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 97
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLAT
Figure
1,2. Globigerinelloides bollii, n. sp.
5,6.
8,9.
10.
11-13.
14,15.
16,17.
18.
19-23.
TE 97
1. PE 1040. TX 291-C. Taylor formation (“Upper Taylor marl” member); half section;
side view; paratype; 100. 2. PE 1041. TX 291-C. Taylor formation (“Upper ‘Taylor
marl” member); vertical section; paratype; 100%.
. Globigerinelloides prairiehillensis, n. sp.
3. PE 1033. TX 291-C. Taylor formation (“Upper T.
aylor marl” member); side view;
half section; paratype; 100%. 4. PE 1035. TX 291-C. Taylor formation (“Upper Taylor
marl’ member); vertical section; paratype; L0Ox.
Globigerinelloides yaucoensis (Pessagno)
5. PE 1031. TX 291-C. Taylor formation (“Upper Taylor marl” member); half section;
side view; 100. 6. PE 1029. TX 291-C. Taylor formation (“Upper ‘Taylor marl’? mem-
ber); vertical section; 100%.
. Globotruncana hilli, n. sp.
PE 944. TX 291-C. Taylor formation (“Upper Taylor
paratype; 100%.
Globotruncana lapparenti (Brotzen)
8 PE 853. TX 251. Taylor formation (“Lower Taylor
1165. 9. PE 852. TX 251. Taylor formation (“Lower
section; 116.
Globotruncana loeblichi, n. sp.
PE 936. TX 375. Taylor formation (“Lower Taylor
100>¢.
Globotruncana linneiana (d’Orbigny)
marl” member); vertical section;
marl” menher); vertical section;
‘Taylor marl’? member); vertical
marl” member); vertical section;
11. PE 923. TX 291-C. Taylor formation (“Upper Vaylor marl” member); vertical sec-
tion; 79.6%. 12 Same specimen; enlargement of anterior double keel; 159. 13. PE
922. TX 291-C. Taylor formation (“Upper Taylor marl’ member); vertical section;
116.
Globotruncana bulloides Vogler
14. PE 908. TX 158. Taylor formation (“Upper ‘Vay
tion; 1169¢. 15. PE 895. TX 251 ‘Taylor formation
vertical section; 116%.
Pseudotextularia deformis (Kikoine)
lor marl” member); vertical sec-
(“Lower Taylor marl’? member);
16. s.l. PE 1132. TX 262-C. Navarro group (Kemp clay); half section; 116. 17. s.s.
PE 1131. MX 174. Papagallos shale. 100.
Pseudotextularia elegans s.l. (Rzehak)
PE 1137. MX 5. Méndez shale; 100.
Globotruncana rosetta (Carsey)
19. PE 888. TX 291-C. Taylor formation (“Upper
Taylor marl’? member); vertical
section; 100%. 20. PE 889. TX 291-C. Taylor formation (“Upper Taylor marl” mem-
ber); vertical section; 1005¢. 21. PE 1143. TX 291-B. 1
marl” member); vertical section; 1005. 22. PE 885.
23. PE 1134. TX 291-B. ‘Vaylor formation (“Upper
section; LOO><.
‘aylor formation (“Upper ‘Taylor
TYPE 4. Méndez shale; 100.
Paylor marl” member); vertical
343
349
346
324
269
437
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 98
Figure Page
1. Marginotruncana bouldinensis, n. sp.
PE 981. TX 105. Eagle Ford group (South Bosque formation); vertical section;
paratype; 120%.
2. Marginotruncana indica (Jacob and Sastry)
PE 969. TX 353. Eagle Ford group (South Bosque formation); vertical section;
1009.
3.4. Marginotruncana renzi (Gandolfi)
3. PE. 976. TX 353. Eagle Ford group (South Bosque formation); vertical section;
100%.
4. PE 962. TX 30. Eagle Ford group (Boquillas formation); vertical section; 1005.
6,7. Marginotruncana sigali (Reichel) :
6. PE 1005. TX 105. Eagle Ford group (South Bosque formation); vertical section;
100%. 7. PE 1000. Hypotype from Sigal; Upper Cretaceous (Turonian of Tunisia);
vertical section; 100>.
5,9-11. Marginotruncana angusticarenata (Gandolfi)
5. PE 958. TN 55. Austin chalk (“Atco’” member); vertical section; 1005. 9. PE
957. TX 55. Austin chalk (“Atco’” member); vertical section; 1005¢. 10. PE 960.
TX 232. Austin chalk (“Atco” member); vertical section; 114. 11. PE 947. TX
36. Austin chalk (“ Atco” member); vertical section; 116 <.
12. Rotalipora evoluta Sigal
PE 1086. TYPE 5-B. Grayson formation (= Del Rio clay); vertical section; 100 .
18. Rotalipora appenninica (O. Renz)
PE 1075. TX 357. Eagle Ford group (Lake Waco formation); vertical section; 100><.
14. Globolruncana roselta (Carsey) J
PE 1144. TN 291-A. Taylor formation (“Upper ‘Taylor marl” member); vertical
section; 116.
15,17-18. Pseudotextularia deformis (Kikoine)
15. s.l. PE 1133. TX 267-C. Navarro group (Kemp clay); 100. 17. s.s. PE 1130.
MX 174. Papagallos shale; 1165¢. 18. s./. PE 1129. TX 267-C. Navarro group (Kemp
clay); 100.
53. Heterohelix striata (Ehrenberg)
PE 1122. TX 244. Taylor formation (“Lower Taylor marl’ member); 100.
19,20 Pseudolextularia elegans s.s. (Rzehak)
19. PE 11386. TN 291-C. ‘Paylor formation (“Upper ‘Taylor marl’? member; 100%.
20. PE 1139. TX 291-C. ‘Paylor formation (“Upper ‘Vaylor marl’? member); 100><.
21. Heterohelix semicostata (Cushman)
PE 664. C-52. Neylandville marl; 100 5¢.
301
307
310
S13
300
269
264
268
265
Plate 98
PALAEONTOGRAPHICA AMERICANA, VOL. V
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 99
GULF CRETACEOUS FORAMINIFERA: PESSAGNO 439
EXPLANATION OF PLATE 99
(AIL photos with dark field illumination)
Figure Page
1,3. Marginotruncana concavala (Brotzen) 304
1. PE 841. TX 242. Austin chalk (“Bruceville” member); vertical section; 100. 3. PE
772. TX 242. Austin chalk (‘“Bruceville” member); half section; LOO»<.
2. Globotruncana ventricosa White 362
PE 810. TX 291-A. Taylor formation (“Upper Taylor marl” member); vertical section;
100%.
4. Marginotruncana helvetica (Bolli) 306
PE 998. ‘TX 105. Eagle Ford group (South Bosque formation); 165 <.
. Marginotruncana marginata (Reuss) 307
5. PE 983. TX 353. Eagle Ford group (South Bosque formation); vertical section; 100 <¢.
6. PE 982. TX 353. Eagle Ford group (South Bosque formation); half section; 176).
7. PE 988. TX. 353. Eagle Ford group (South Bosque formation); half section; 165 >.
=
T
“I
440
PALAEONTOGRAPHICA AMERICANA (V, 37)
EXPLANATION OF PLATE 100
(All photos with dark field illumination)
Figure
~I
9}
r
. Loeblichella hessi (Pessagno)
1. PE. 1054. TX 311, Eagle Ford group (Britton formation); half section; 165X. 2
1051. TX 311. Eagle Ford group (Britton formation); vertical section; 165.
. Globigerinelloides bollii, n. sp... 5
PE 1040. TX 291-C. Taylor formation (“Upper ‘Taylor marl” member); paratype; 165.
. Marginotruncana helvetica (Bolli)
PE 997. TX 105. Eagle Ford group. (South Bosque formation); last chamber injured
assumedly during life of individual; vertical section; 165.
Whiteinella inornata (Bolli)
299
PE 1013. TX. 105. Eagle Ford group (South Bosque formation); vertical section; 165.
}. Marginotruncana coronata (Bolli)
PE 1012. TX 105. Eagle Ford group (South Bosque formation); 165%.
. Praeglobotruncana delrioensis (Plummer)
PE 1049. TX 423. Grayson formation; 165 x.
. Whiteinella archaeocretacea, Nn. sp. :
PE 1015. TX 105. Eagle Ford group (South Bosque formation); paratype; 165.
Globigerinelloides volutus (White)
PE 1044. TX 291-A. Taylor formation (“Upper Taylor marl” member); 165.
305
286
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 100
PALAEONTOGRAPHICA AMERICANA, VOL. V Plate 101
GULF CRETACEOUS FORAMINIFERA: PESSAGNO
EXPLANATION OF PLATE 101
(Figures 1-7 with dark field illumination; figures 8-9 with cross nicols) .
Figure Page
1-2.
3-4.
or
8-9.
Rotalipora appenninica (O. Renz) 289
1. PE 1056. MX 156. San Felipe formation; vertical section; 100 5¢. 2. PE 1076. TX 5.
Eagle Ford group (Chispa Summit formation); vertical section; 100).
Rotalipora greenhornensis (Morrow) 295
3. PE 1061. MX 156. San Felipe formation; vertical section, 1009¢. 4. PE 1057. MX 156.
San Felipe formation; vertical section; 100 <.
- Rotalipora cushmani (Morrow) 292
5. PE 1090. TX 357. Eagle Ford group (Britton formation); vertical section; 100. 6.
PE 1088. TX 357. Eagle Ford group (Britton formation). Note pores in septal wall;
vertical section; 100%. 7. PE 1091. TX 5. Eagle Ford group (Chispa Summit formation);
vertical section; 100.
Wall structure of Rugoglobigerina rugosa (Plummer) 366
Showing radial hyaline, perforate principal wall (R) and ultragranular hyaline, imper-
forate (U) rugosities or costellae. Ultragranular hyaline, calcite material is plastered on
radial hyaline, perforate part of test, tending to choke off pores. PE 1147-48. TX 267-C.
Kemp clay; About 1000x.
441
INDEX
NUMBER 3
Note: Light face figures refer to the page numbers. Bold face figures refei
to the plate numbers.
A
Abathomphalus 371
acervulinoides,
Planoglobulina 87 271
ackermanni,
Globotruncana 350
aegyptiaca,
Globotruncana 79, 83, 94, 95 319
Aldama, Mexico m 376
alexanderi,
Hastigerinoides 60 273
amabilis,
Hedbergella 52 281
angusticarenata,
Marginotruncana 65, 98 300, 301
appenninica,
Rotalipora 50, 51, 98, 101 289, 290
aprica,
“Ticinella” 298
arca,
Globotruncana 79, 90, 96 321
archaeocretacea, n. sp.,
Whiteinella 51, 54, 100 299
Archaeoglobigerina, n. gen. 315
Arkansas, S.W. 380
Arroyo Pedregoso, Mexico 376
aspera,
Rotalia 275
asperus,
Globigerinelloides 60 274
asymetrica,
Globotruncana 304
Austin area, Texas 380
Austin Chalk (age of type Austin) 359
austinensis,
Globotruncana 82, 94 323
B
Banner and Blow; classification of
Globigerinacea 252
Barranco, Mexico 376
beldingi s.s.,
“Globotruncana (Rugoglobigerina)” 279
beldingi subbeldingi,
“Globotruncana (Rugoglobigerina)” 278
bentonensis,
Globigerinelloides 76 275
biforaminata,
Globigerinelloides 277
Biglobigerinella 275
blowi, n. sp.,
Archaeoglobigerina 59, 94 316
Boca Canyon, Mexico 376-377
Bolli, et al.; classification of
Globigerinacea 252
bollii, n. sp.,
Globigerinelloides 76, 81, 97, 100 275
bosquensis, n. sp.,
Archaeoglobigerina 60 316
Bouldin Creek, Travis County, Texas 378
bouldinensis, n. sp.,
Marginotruncana 54, 56, 98 301
brittonensis,
Hedbergella 48 282
Bronnimann and Brown (see emendations
on wall structure of Globigerinacea) 252
442
bronnimanni, n. sp.,
Praeglobotruncana : 49
bronnimanni,
Pseudotextularia
brotzeni,
Thalmanninella
bulloides,
Globotruncana 64, 67, 73, 75, 97
calearata
Globotruncana : 64, 72, 93, 94
Calcite crust
caliciformis
Globotruncana
Cameron Park, McLennan County, Texas
canaliculata,
Marginotruncana 3 74 302,
carseyae,
Planoglobulina 87
caseyae,
Globigerinelloides 49
cenomana,
Schackoina 3 48
Chispa Summit, Jeff Davis County,
Texas : :
Ciudad del Maiz, Mexico
Ciudad Mante, Mexico
Ciudad Valles, Mexico
Ciudad Victoria, Mexico
Clavihedbergella
coarctata,
Loeblichella 48, 61, 62, 76
Coco Station neues ee area O8
coldreriensis,
Globotruncana
concavata,
Marginotruncana 58, 95, 99
conica,
Globotruncana Ch C3, Se)
contusa s.l.,
Globotruncana 75, 77, 92, 96
contusa s.s.,
Globotruncana 77, 78, 92, 96
coronata,
Marginotruncana 65, 100
cornuta,
Pseudoguembelina ie 2:
“Corsicana Clay Pit” ee
costulata,
Pseudoguembelina 79, 88, 90
Cow Creek, Kinney County, Texas nee Per,
cretacea,
Archaeoglobigerina 70, 94
cretacea,
Globotruncana
cretacea,
Guembilitria 87
cushmani,
Rotalipora 51, 101
Dallas area
decoratissima,
Gublerina Spee
deformis,
Pseudotextularia 90, 92, 97, 98
286
....269
297
324
326
314
359
3719
303
271
276
279
TT
376
376
375
_....376
_ 285
288
3875
310
304
328
330
330
305
267
380
266
378
317
352
258
292
379
265
269
delrioensis,
Hedbergella
delrioensis,
Praeglobotruncana
difformis,
Marginotruncana
duwi,
Globotruncana
Eagle Pass, Maverick County, Texas
Edelbachgraben (Austria) :
ehrenbergi,
Globigerinelloides
elegans s.l.,
Pseudotextularia
elegans s.s.,
Pseudotextularia
elongata,
Pseudotextularia
elevata,
Globotruncana
esnehensis,
Globotruncana ...
Evans Creek, Val Verde County,
Texas .... ;
evoluta,
Rotalipora
excolata,
Pseudoguembelina
falsostuarti,
Globotruncana
First striate Heterohelicidae
fornicata,
Globotruncana
fructicosa,
Racemiguembelina
fundiconulosa,
Globotruncana
galeoides,
Globotruncana
gansseri,
Globotruncana
glabrans,
Heterohelix
glabrata,
Planoglobulina
glaessneri,
Gublerina
Globigerinelloides
globocarinata,
Heterohelix
Globotruncana
Globotruncanella
globulosa,
Heterohelix
Gonzalez
Gosau
greenhornensis,
Rotalipora
Gublerina
Guembilitria
Guerrero (=Tamuin), Mexico
H
Hacienda El Limon, Mexico
harrisi,
Guembilitria
48
52, 100
54, 56, 99
83, 95
thy &P/
85, 88, 89, 98
78, 80, 81, 93
49, 53, 98
68, 90
63, 80, 96
90
To; 092, 99)
50, 51, 101
...323,
. 48
INDEX
282
286
307
333
378
381
276
268
268
268
336
357
377
294
266
357
258
338
270
304
332
341
259
272
265
274
259
318
372
260
376
381
295
265
258
375
376
258
445
Hastigerinoides
havanensis,
Globotruncanella
Hedbergella
helvetica,
Marginotruncana
hessi,
Loeblichella .
Heterohelix ..
hexacamerata,
Rugoglobigerina
hilli, n. sp.,
Globotruncana
homedelensis,
Hedbergella (?)
hozli,
Globigerina
imbricata,
Marginotruncana
indica,
Marginotruncana
inornata,
Whiteinella
intermedia,
Pseudotextularia
jerseyensis,
Globotruncanella
Jirova’s neotype for Rosalina
marginata Reuss
lapparenti s.s.,
Globotruncana
leupoldi,
Globotruncana
linneiana,
Globotruncana
Loeblichella, n. genus
loeblichi, n. sp.,
Globotruncana
Lozier Canyon, Terrell County, Texas
lugeoni,
Globotruncana
Luzice, Northern Bohemia
Manuel, Mexico
Mamulique Pass, Mexico
marginata s.s.,
Marginotruncana
Marginotruncana
mattsoni,
Hedbergella (?)
mayaroensis,
Abathomphalus
Méndez Station, Mexico
messinae s.s.,
Globigerinelloides
monmouthensis,
Globotruncanella
moremani,
Heterohelix
moremani,
Clavihedbergella
Moore’s Crossing, Travis County, Texas
multicamerata,
Planoglobulina
53, 54, 99, 100 306
48, 61, 100 288
258
74, 91 364
64, 94, 97 343
... 283
298
ees 306
55, 57, 98 307
71, 100 299
86 269
sinsteaonester 374
307
71, 97 344
See 340
72, 97 346
soncseecaaa4 OS)
73, 97 349
301
342
307
376
377
307
299
50 283
927,95) 3712
377
278
61 374
48, 89 260
53, 55 285
378
89 272
multispina,
Globigerinelloides
multispinata,
Schackoina
navarroensis,
Heterohelix
nothi,
Globotruncana .
ie)
Onion Creek, Travis County, Texas
P
Palmer, Ellis County, Texas
palpebra,
Pseudoguembelina
patelliformis,
Globotruncana
Peregrina Canyon
petaloidea,
Globotruncanella
Pinto Creek, Kinney County, Texas
planata,
Heterohelix .
Planermergel
planispira,
Hedbergella
Planoglobulina
plicata,
Globotrunecana
plummerae,
Globotruncana
Plummerita
Praeglobotruncana
praehelvetica,
Whiteinella
Prairie Hill, Limestone County, Texas
prairiehillensis, ne Sp:
Globigerinelloides
Pseudoguembelina
pseudolinneiana, n. sp.,
Marginotruncana
Pseudotextularia
pulchra,
Heterohelix
punctulata,
Heterohelix
Racemiguembelina
reicheli,
Rugoglobigerina
renzi s.s.,
Marginotruncana
repanda,
Globotruncana
reussl,
Heterohelix .
Rio Grande area .....
Rio Huiches, Mexico
robusta,
Gublerina ....
rosetta,
Globotruncana
Rotalipora
rotundata,
Rugoglobigerina
Rugoglobigerina
rugosa,
Rugoglobigerina
Rugotruncana
70, 82, 91
60
89
67, 68, 96
78, 89
82
86, 89
307,
51, 53
66, 96
60, 83, 90, 97
. 65, 76
87
86
65, 68
55, 65, 98 310,
85, 86
75
70, 73, 97, 98
65, 68
75, 101
INDEX
S
276 Schackoina
scotti,
280 Rugoglobigerina
schneegansi,
Globotruncanaiee eee ee ee
261 semicostata,
Heterohelix
350 Shoal Creek, Travis County, Texas
Sierra del Abra, Mexico
Sierra Madre Oriental
sigali,
eae Marginotruncana
simplex,
380 Clavihedbergella
South Bosque River, McLennan County,
267 Texas
spinea,
332 elobolrungans
spinifera,
378 Heterohelix
374 stephani,
378 Praeglobotruncana
stephensoni, n. sp.,
261 Globotruncana
309 striata,
Heterohelix
283 stuarti s.s
271 Globotruncana
stuartiformis,
332 Globotruncana
subcearinatus,
351 Globigerinelloides
364 subcircumnodifer,
286 Rugotruncana
subpennyi,
306 Rugotruncana
380 Sycamore Creek, Val Merde Kinuey.
County line, Texas
277
265 T
310 Tradinghouse Creek, McLennan ee
267 Texas
tradinghousensis, n. sp.,
262 Rugoglobigerina
tricarinata,
Globotruncana
262 trinidadensis,
Globotruncana
270 Trinitella
365 U
ultimatumida,
312 Heterohelix
255 Vv
ventricosa,
263 Globotruncana
376 ventricosa carinata,
Globotruncana
265 volutus (=messinae s.s.),
Globigerinelloides
352 ‘
289 Ww
Waco area, Texas
365 washitensis,
... 364 Hedbergella
watersi,
366 Hastigerinoides
368 Webberville Road, Texas
279
74, 76 367
Libs veseveenene 313
i 1298 263
sess soabereteee 378
376
305, 317
54, 56, 57, 98 313
Sige 52 285
379
.. 804
see 260
eee 50 287
re 69, 96 354
78, 88, 98 264
81, 93, 94 356
80, 92, 93 357
. 62 278
62, 74 369
76, 91 370
377
379
. 64 367
346, 348
84, 90, 96 359
364, 367
264
75, 79, 95, 99 362
304
62, 100 278
239
vee AY 284
51, 71 274
Leo
I HS ge Th
INDEX
White Cliffs Landing, Sevier County,
Arkansas F 380
Whiteinella 298
White Rock Creek : 304
wilsoni,
Marginotruncana ; 309
Vy
yaucoensis,
Globigerinelloides 75, 97 279
XXXIX.
XLI.
XLII.
XLIII.
XLIV.
XLV.
XLVI.
XLVII.
XLVIII.
XLIX.
LII.
Volume I.
II.
Il.
IV.
(Nos. 177-183). 448 pp., 36 Pls. cesecssecssecscsesnessssneenssensesnsensssnsess
Panama Caribbean mollusks, Venezuelan Tertiary formations
and forams, Trinidad Cretaceous forams, American-Eur-
opean species, Puerto Rico forams.
(No. 184). 996 pp., 1 pls. .sseerecsecrssneersersensesessessessecsnsssssssssnsansenennees
Type and Figured Specimens P.R.I.
(Nos. 185-192). 381 pp., 35 Pls. -secsecersssesessessenessersssessseeseessasenenees
Australian Carpoid Echinoderms, Yap forams, Shell Bluff,
Ga. forams. Newcomb mollusks, Wisconsin mollusk faunas,
Camerina, Va. forams, Corry Sandstone.
(No. 193). 673 pp., 48 pls. ...rescccseccnecnccnsessesneccnessneensssnesssesssessecenens
Venezuelan Cenozoic gastropods.
(Nos. 194-198). 427 pp., 39 Pls. s.rcessesssssesnsrsrnsrnssnssnsressnssssencenssnees
Ordovician stromatoporoids, Indo-Pacific camerinids, Missis-
sippian forams, Cuban rudists.
(Nos. 199-203). 365 pp., 68 Pls. ...sesssecssesessecsesssecsessnssssssnsssneennense
Puerto Rican, Antarctic, New Zealand forams Lepidocyclina,
Eumalacostraca.
(No. 204). 564 pp., 63 pls. crrecsecsecsssecsessecssssssssnsssnesnnsanecnneenesnes
Venezuela Cenozoic pelecypods
(Nos. 205-211). 419 pp., 70 pls. --secssecseecsecseecseecsecssssssesnsencssesssenes
Large Foraminifera, Texas Cretaceous crustacean, Antarctic
Devonian terebratuloid, Osgood and Paleocene Foramini-
fera, Recent molluscan types.
(Nos. 212-217). 584 pp., 83 pls. -ssscesssesseccnesssessneessesssnsessseennecsneses
Eocene and Devonian Foraminifera, Venezuelan fossil
scaphopods and polychaetes, Alaskan Jurassic ammonites,
Neogene mollusks.
(No. 218). 1058 pp., 5 pls. .se-rseersessssecsnessnsssnesssssssnsecenssnecennesnneesiees
Catalogue of the Paleocene and Eocene Mollusca of the
Southern and Eastern United States.
(Nos. 219-224). 671 pp., 83 P13. serseesssesssesssssssseernseescestecsneecnsesssses
Peneroplid and Australian forams, North American carpoids,
South Dakota palynology, Venezuelan Miocene mollusks,
Voluta.
(Nos. 225-230). 518 pp., 39 pls. se-csssscsssssssseesssssessneeessnnseessnnsessens
Venezuela and Florida cirripeds, Antarctic forams, Linnaean
Olives, Camerina, Ordovician conodonts, Niagaran forams.
(Nos. 231-232). 420 pp., 10 pls. crseessssessssessssssecsssessensesssneecnnsseesnecs
Antarctic bivalves, Bivalvia catalogue.
(Nos. 233-235). 208 pp., 32 pls. ...--seesssessssesseseeseesneseneesnneennsssnssenes
New Zealand forams, Stromatoporoidea, Indo-Pacific
forams.
PALAEONTOGRAPHICA AMERICANA
See Johnson Reprint Corporation, 111 Fifth Ave., New York,
N.Y. Monographs of Arcas, Lutetia, rudistids and venerids.
(Nos. 6-12). 531 pp. 37 pls. ressssesssrsssssessnessersnneseennnnensnnsesescens
Heliophyllum halli, Tertiary turrids, Neocene Spondyli, Pale-
ozic cephalopods, Tertiary Fasciolarias and Paleozoic and
Recent Hexactinellida.
(Nos. 13-25). 513 pp, 61 pls. ---ssssesssssveessssneeecesnnseeesenneersennerssenss
Paleozoic cephalopod structure and phylogeny, Paleozoic
siphonophores, Busycon, Devonian fish studies, gastropod
studies, Carboniferous crinoids, Cretaceous jellyfish, Platy-
strophia, and Venericardia.
(Nos. 26-33). 492 pp., 72 PSs esscevevecestecvaneastersacstascareerenscnccm=snros
Rudist studies, Busycon, Dalmanellidae, Byssonychia, De-
yonian lycopods, Ordovician eurypertids, Pliocene mol-
lusks.
(Nos. 34-36). 241 pp.) 47 pls. ..-scsssssccsssesesesneeccsnnneeeeennetennnsssecees
Tertiary Arcacea, Mississippian pelecypods, Ambonychiidae.
16.00
16.00
16.00
16.00
16.06
16.00
16.00
16.00
16.00
18.00
16.00
16.00
16.00
8.25
21.00
25.00
25.00
15.60
Vols.
XXIV.
XXV.
XXVI.
XXVII.
XXVIII.
XXIX.
XXX.
XXXII.
XXXII.
XXXII.
XXXIV.
XXXV.
XXXVI.
XXXVII.
XXXVIII.
BULLETINS OF AMERICAN PALEONTOLOGY
I-XXIII. See Kraus Reprint Corp., 16 East 46th St., New York,
N.Y. 10017, U.S.A.
(Nos: 802872). 334 pps, 27 ip lSitccrcsescacteccccenecvonccterecoreccersearrncerence 10.50
Mainly Paleozoic faunas and Tertiary Mollusca.
(INo06:788-94B) a3 060 pp 3 Olip) Staececects-ccstvcrencesceareeee teste ccensnecesccares 10.0
Paleozoic fossils of Ontario, Oklahoma and Colombia, Meso-
zoic echinoids, California Pleistocene and Maryland Mio-
cene mollusks.
(INO62195=100) 42 Ol pps wo Supls ssettecsssresscece-ee-secteseeseremnrereresecoves 12.00
Florida Recent marine shells, Texas Cretaceous fossils, Cuban
and Peruvian Cretaceous, Peruvian Eogene corals, and
geology and paleontology of Ecuador,
(Nos; 1OT=108)= Si76uipps, SGmp] siirerscerrse-c-k. cer seeneccsestrceseresseceteee 12.06
Tertiary Mollusca, Paleozoic cephalopods, Devonian fish and
Paleozoic geology and fossils of Venezuela.
(Noss 109-114) sr 41 2p pir balan ence scectccrtetscscessccceecsorexesecevecree 12.00
Paleozoic cephalopods, Devonian of Idaho, Cretaceous and
Eocene mollusks, Cuban and Venezuelan forams.
(Noss oHES=116)\5 “738 pple 52 spl se cesece-ceccstecccsevsearsescovencvsecccreceerese 18.00
Bowden forams and Ordovician cephalopods.
(ON OSSD7) 75163) Pps AOSD Ss eccacececcctrscceve evasasevecscacoscrcrcyneacaeatactennees 16.00
Jackson Eocene mollusks.
(Noss 118-128) 0 x4S8) pps 27) (pl sagicsec-cecsveceeretteecrscerecconenersrecteree 12.00
Venezuelan and California mollusks, Chemung and Pennsyl-
vanian crinoids, Cypraeidae, Cretaceous, Miocene and Re-
cent corals, Cuban and Floridian forams, and Cuban fossil
localities.
(Nos 1292133) 5 9294 pps) SO op sameece cccercrcartssssecscesesreesneeereerere 12.00
Silurian cephalopods, crinoid studies, Tertiary forams, and
Mytilarca.
(Nosi91342139)") S44 8) ip pre Sills pl aseraces cocceeccuncctectecereccecesconsrecterets 14.00
Devonian annelids, Tertiary mollusks, Ecuadoran strati-
graphy paleontology.
(Nos. 140-145). (4.00 pp. 1 9)ep!Sinese cress eecvescore ecsctsedesaracererssce 13.00
Trinidad Globigerinidae, Ordovician Enopleura, Tasmanian
Ordovician cephalopods and Tennessee Ordovician ostra-
cods and conularid bibliography.
(WNos146-154) SS Gmpp al tpl SatecerccccereccrsatencesAesereronceonseeceeteresa 16.00
G. D. Harris memorial, camerinid and Georgia Paleocene
Foraminifera, South America Paleozoics, Australian Ordo-
vician cephalopods, California Pleistocene Eulimidae, Vol-
utidae, and Devonian ostracods from Iowa.
(Nos. 155-160) 4:02) ppyeeSie DISaic-cccrosscresneecescrsteesrseetencceceecescee 16.00
Globotruncana in Colombia, Eocene fish, Canadian Chazyan
fossils, foraminiferal studies.
(Nos: 1612164) 54:86 ppg 70 DIS iiecccccnncessceececesvecesteccersrscecnceevensearseae 16.00
Antillean Cretaceous Rudists, Canal Zone Foraminifera,
Stromatoporoidea.
(Nos: 1652176) 447s pps OSs tees emi ncrerst ee secrermraesescerece 16.00
Venezuela geology, Oligocene Lepidocyclina, Miocene ostra-
cods, and Mississippian of Kentucky, turritellid from Vene-
zuela, larger forams, new mollusks, geology of Carriacou,
Pennsylvania plants.
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