Vertebrate fossils from the Blanco local fauna of Texas

OCCASIONAL PAPERS

THE MUSEUM

TEXAS TECH UNIVERSITY

NUMBER 30 23 MAY 1075

VERTEBRATE FOSSILS FROM THE
BLANCO LOCAL FAUNA OF TEXAS

Walter W. Dalquest

Vertebrate fossils were discovered near Mount Blanco, in Crosby
County, Texas, in 1889, and reported the following year (Cummins,
1890). In the next few decades, a number of institutions made collec¬
tions at Mount Blanco, and several publications describing the sedi¬
ments and fauna resulted (for example. Cope, 1893; Gidley, 1903
a , b). Later, Evans and Meade (1945) discussed the geology of the
Blanco Formation, and Meade (1945) added materially to the knowl¬
edge of the fauna. The Blanco local fauna has become the type local
fauna for the Blancan Stage, Blancan Mammalian Age and Blancan
fauna. Blancan local faunas have been described from numerous sites
in North America, and many authors have correlated other Blancan
local faunas with the type Blanco local fauna.

Current knowledge of the Blanco local fauna rests largely on the
studies made prior to 1910, as modified by the work of Meade ( loc .
cit.) in the 1940’s. The known mammals are virtually all large
species, with long time ranges, and even these are incompletely
known. Microvertebrates, so important in detailed correlations, have
been unknown. Errors in identification of taxa and much controversy
and speculation have occurred. As a result, the Blanco local fauna is
perhaps the least understood of the classical local faunas that are the
types of Mammalian Ages of North America.

In 1964, the late J. S. Bridwell granted permission to the Biology
Department of Midwestern University to carry on excavations in the
Blanco Formation, the bulk of which occurs on one of the Bridwell
ranches. During the next four years, and intermittently since then,
field parties collected in the Blanco sediments. A fairly good under¬
standing of the geology was obtained, the known vertebrate fauna of

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the Blanco was more than doubled, and a much better knowledge of
the age of the Blanco local fauna, and its place in the Blancan
chronology, is available.

Historical Background

The Blanco site and its vertebrate fossils were discovered by W. R
Cummins in 1889 (Cummins, 1890, 1891, 1892). In 1892, E. D,
Cope visited the Blanco beds with Cummins and wrote several short
papers (Cope, 1892 a-g) about the formation and fauna and a report
(Cope, 1893) of major importance. H. F. Osborn, of the American
Museum of Natural History, sent expeditions under the charge of
J. W. Gidley to the Blanco in 1900 and 1901 (Gidley, 19036). The
latter paper included the first detailed list of the vertebrate fauna, and
this list is still a major source of knowledge of the Blanco local fauna.
W. D. Matthew collected fossils in the Blanco Formation in 1924 and,
according to Meade (1945), the results of his work are included in an
unpublished manuscript. Only brief notes concerning the Blanco were
ever published (Matthew, 1924n, 6, 1925). No original contributions
to the knowledge of the Blanco fauna appeared during the next two
decades, although Blancan faunas from elsewhere in the United States
were described, and Gazin (1936) updated Gidley’s (1903) faunal
list.

In 1940 and 1941, G. L. Evans and G. E. Meade made extensive
collections in the Blanco Formation and reported briefly on the
geology (Evans and Meade, 1945) and in detail on the vertebrates
collected (Meade, 1945). Thereafter, no additional work seems to
have been done, although Hibbard (1950) reported the giant ground
squirrel from the Blanco and a specimen of bone-eating dog from a
site that is doubtless in the Blanco Formation. Numerous mentions of
the Blanco and its fauna were made during following decades, and
Johnston and Savage (1955) published an updated faunal list, basi¬
cally the same as that of Gidley (19036) but with additions from
Meade (1945).

Terminology

I have noted (Dalquest, 19726:570) that, although it is certainly
undesirable to use the same noun (Blanco) as part of the name
of a rock unit (formation), time unit (stage, land-mammal age), and
faunal unit (fauna, local fauna), an exception should be made for
“Blanco." The name Blanco has been employed in all of these senses,
often for many decades, and no alternatives have ever been proposed.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

3

To substitute another term at this late date would only lead to
confusion, not clarity, and defeat the purpose of technical terminology.

The following usages are probably acceptable. Each is followed by
the original forms employed, author, and date.

Blanco Formation:

Blanco Canyon Beds, Cummins, 1890.

Blanco Beds, Cummins, 1891.

Blanco Formation, Matthew, 1925; Gidley, 1926.

Blanco local fauna:

Blanco local fauna, Johnston and Savage, 1955.

Blancan stage:

Blanco stage, Gazin, 1936.

Blancan fauna:

Blanco fauna, Meade, 1945.

Blancan North American Land-Mammal Age:

Blancan North American Land-Mammal Age, Evernden, et a/.,

1964.

The Blanco Formation was proposed by Cummins (1890), “I have
given them the name of Blanco Canyon beds.” At this time “bed” was
used in the sense of a formation. In 1892, Cummins actually stated
(p. 201) “this formation,” but never used the combination Blanco
Formation. Matthew, more than 20 years later, seems to have been
the first to do so. The type locality is Mount Blanco, where Cummins
(1892) measured a section, refigured by Gidley (19036). Evans and
Meade (1945) presented another measured section, refigured by John¬
ston and Savage (1955).

There may be objection to the use of “Blanco Formation” for sedi¬
ments occupying such a restricted area. The white beds of the Blanco
Formation are set into the brown sediments of the Bridwell Forma¬
tion (Johnston and Savage, 1955:36), and separated from them by
a sharp contact that represents an erosional unconformity between
the two differently colored and lithologically distinct kinds of sedi¬
ments. The fossils of the Bridwell Formation are of middle Plio¬
cene age (Meade, 1945:516), and the disconformity represents several
million years, at least. Whether the Bridwell Formation deserves
recognition as a distinct formation is not at issue. In the absence
of another category for lithologically (and chronologically) distinct
and mapable units of rock that are of limited geographic extent but
of paleontological importance, it seems best to retain them as forma¬
tions. The distinctness of the Blanco as a rock unit has been recog¬
nized and accepted for nearly a century.

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The term “Blanco” has been used so long and it is so familiar that
it has often been used in the singular, “the Blanco,” usually in refer¬
ence to the sediments themselves but sometimes in other senses. It is
suggested that this usage be restricted to the formation itself.

Sediments

The Blanco Formation is exposed in a section approximately a
mile long and not more than 70 feet maximum thickness, on the north
side of Crawfish Draw, 11 miles north of Crosbyton, Crosby County,
Texas. Since measured sections have been presented elsewhere (see
Terminology), one is not given here. The deposit, as seen from the
south side of Crawfish Draw, a mile away, has a shallow lenticular
shape and appears white. At closer range, the white color is empha¬
sized, but study of the individual layers shows that a pale gray or
greenish color predominates.

Bedding is strong, with the contacts of layers of different materials
sharply marked. Massive clay deposits, gray to grayish white in
color, and greenish sand are most common but layers of indurated
sandstone, caliche gravel and freshwater limestone also are present.
Volcanic ash is apparently mixed through the sediments; most clays
are bentonitic. The few' diatomite beds are restricted in area.

The genesis of the Blanco strata has been controversial since Cum¬
mins (1892) thought that the beds originated in a great inland sea.
Gidley (19036) denied a lacustrine origin, and considered the sedi¬
ments to be a narrow valley or basin fill. Baker (1915) and others
agreed with this, and the valley fill origin of the Blanco was not ques¬
tioned until Evans and Meade (1945) and Meade (1945) rejected this
theory and postulated the existance of a large, mostly permanent lake,
the fillings of which formed the Blanco deposit.

It should be noted that the concept of the extent of the Blanco has
decreased steadily. Cummins used the term for sediments covering
much of West Texas and the Panhandle. Gidley (19036) and Baker
(1915) greatly restricted the extent of deposits attributed to the
Blanco Formation but included some disjunct sediments. When Gidley
{op. cit ., 625) wrote about stream or river deposition of the Blanco,
he visualized the deposits as extending “eastward fifteen or twenty
miles to the edge of the plains.” Evans and Meade (1945) included
in the Blanco Formation only the main Crawfish Draw site and a small
area 6 miles northeast of Crosbyton. Apparently the Blanco Forma¬
tion includes only the single limited deposit at the junction of Craw¬
fish Draw and Blanco Canyon and the site near Crosbyton.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

5

There are some puzzling features about the Blanco sediments, and
some contradict the concept of a permanent or partly permanent
lake occupying a closed depression of considerable extent. For one
thing, I found no remains of fishes or aquatic turtles anywhere in the
deposits, although a single alligator tooth was taken in one quarry.
No aquatic snail fossils were found anywhere except in the obvious¬
ly lacustrine deposits under the diatomite.

Evans and Meade (1945:492) listed four main reasons for thinking
the Blanco sediments lacustrine: 1) the gravels are derived from the
local caliche caprock and are found exclusively on the marginal
slopes of the basin; 2) main strata of the exposed beds are traceable
over the exposed areas; 3) some sediments, such as the bentonitic
clays, freshwater limestones and diatomite, indicate quiet water depo¬
sition; 4) there is no evidence of connection between the two Blanco
deposits and other sediments of proven similar age that might indicate
that the Blanco was a valley filling.

With regard to 1 above, I found two places, one quite extensive,
where gravels are present in a thick layer near the base and center of
the apparent basin. As for point 2, it is often difficult to be sure sand
or limestone layers on the opposite sides of a hill are actually ex¬
posures of a continuous layer, for the different strata of sand, lime¬
stone or sandstone are often very similar lithologically and in color.
However, in general it is true that the major strata do seem to have
considerable geographic extent.

More striking, however, is the abrupt discontinuity of many ele¬
ments of the minor stratigraphy. A clay bed or sand stratum may
end abruptly, usually sand replacing clay or the reverse. Sandstones
and caliche often pinch out in short distances. This condition might
occur in sediments formed in a lake with numerous embayments, but
is in strong contrast to the even, uniform sediments typical of the de¬
flation basins of West Texas, as described by Evans and Meade
(1945).

The bentonitic clays and freshwater limestones (point 3) indicate
still waters, but these might have occupied low areas or small,
temporary depressions after floods or heavy rains. This type of depo¬
sition occurs today in arid areas. The diatomite, however, definitely is
a lacustrine deposit. The sandy mud deposit beneath the diatomite
beds can often be traced laterally for 100 yards or more away from
the diatomite itself. The deposits are clearly recognizable as pond
deposits by their evenness and uniformity of sediments, and by their
contained fossils. Remains of aquatic plants are abundant, and some
few fossil aquatic snails also occur. The ponds, however, were shal-

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low and apparently limited to areas of a few acres. No fish or aquatic
turtle remains have been found, and fossil wood and hackberry seeds
are usually as abundant as fossils of emergent vegetation. It should be
emphasized that these deposits within the Blanco sediments are readily
recognized as laucustrine.

As to Evans and Meade’s point 4, it may be argued that a connect¬
ing valley did exist, but has been removed by erosion in the present
miles-wide valley of White River.

The absence of fossils of aquatic vertebrates and the varied nature
of the sediments in the Blanco Formation argue against a closed de¬
pression occupied by a lake. It seems more likely that the deposits
accumulated in a shallow drained rather than closed basin, formed
by stream erosion or deflation. Coarser materials were deposited on
the valley slopes but floods or mudflows carried some gravels far out
into the valley. Slope wash and wind-blown materials Filled the basin,
the materials being sorted and reworked by wandering shallow
streams during wet intervals. Heavy rains, perhaps seasonal, carried
clay materials that accumulated in low areas. Dry intervals per¬
mitted accumulation and leaching of carbonates into sands and clay
deposits to form the calcareous limestones and caliche.

Collecting Sites

The microvertebrate fossils here reported were obtained from
more than 100 tons of matrix collected from three quarries. In addi¬
tion to the matrix processed by Midwestern personnel, a large but
unknown quantity of matrix from one of these quarries was washed
and sorted by John and Lillian Carter, and the Carter collection was
purchased later by Midwestern University. The specimens obtained
by the Carters are included in this report, as noted below.

Not included in the above totals are many tons of matrix collected
at various sites in the Blanco Formation in an attempt to find a con¬
centration of microvertebrate fossils. Samples of a few hundred
pounds to a ton or more of matrix were taken from 20 or more poten¬
tially productive sites, but yielded only about two Sigmodon teeth to
the ton. A few Sigmodon teeth apparently can be found in virtually
any sandy clay matrix in the Blanco deposits. These sites and speci¬
mens are not dealt with further, except for a few important isolated
finds. Preservation of Blanco fossils is such that few surface finds are
complete enough to identify. It is probable that, in the course of this
work, nearly 150 tons of matrix were processed.

The main fossiliferous portions of the Blanco Formation are pep¬
pered with quarries. The University of Texas quarries, operated by

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

7

Meade and Evans in the 1940’s, were mapped incorrectly by Meade
(1945:510) but were described (pp. 519-520) and are easily located.
The many other old quarries must have been excavated in the early
1900’s or earlier, and their pits, and even the hundreds of bone frag¬
ments surrounding them, attest to the ineffective erosion in the dry
climate and sandy sediments of the Blanco.

The microvertebrate quarries operated by Midwestern University
are located with reference to Meade’s {op. cit ., 519-520) descriptions,
as follows.

Low Quarry .—Approximately 50 yards north of, and up the small
canyon from, Meade's Quarry 11 (his main Gigantocamelus quarry).
Here an 18-inch thick layer of sandy clay is more resistant than the
sands above and beneath and forms a ledge. Forty tons of matrix
from this ledge were processed and yielded a kangaroo rat jaw, a cot¬
ton rat jaw, a few other jaw fragments, and numerous isolated teeth.
Mastodon remains were numerous, and a few specimens of horse and
peccary also were obtained. Notable is a single tooth of a large
crocodilian. Preservation of both bones and teeth is excellent. This site
is approximately 12 feet above the contact with the underlying mid¬
dle Pliocene deposits and is the lowest productive microvertebrate
site discovered.

Red Quarry .—Same as Meade’s Quarry 6, 28 feet above the basal
contact. Here, a thick bed of diatomite overlies a sandy clay. The
clay originally formed the bottom of a shallow, vegetation-clogged
pond and it contains countless rounded cavities from less than a
millimeter to several millimeters in diameter, resulting from decom¬
position of organic debris. The upper portion of the clay layer and
the lower part of the diatomite layer contain abundant white fossil
plant remains. The bulk of the fossils are of rushes and other aquatic
types, but seeds of the hackberry tree are common. Small mammals
are represented by a mole, a shrew, rabbits and several kinds of
rodents, recovered from approximately 50 tons of matrix. Large mam¬
mals include a three-toed horse, a sloth, and others, found both in the
diatomite and in the clay. The bones and teeth from this site often are
distinctly red in color. Most bone is very poorly preserved but
teeth are usually in fair condition.

Carter Quarry .—Between Meade’s Quarry 17 and the Red Quarry.
The Carters worked in this quarry intermittently for more than a year,
and both large mammals and microvertebrates were obtained. The site
is a massive clay bed about 50 yards from, and at the same level as, the
Red Quarry, above. After the Carter collection was obtained, further
excavation was carried out, and much additional material was ob-

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Fig. 1. —Map of the Blanco area. Numbered sites, marked with crosses, are
corrected localities of University of Texas quarries, described by Meade (1945:
519-520). Letters indicate (north to south) sites of: GA, Guaje Ash; LQ, Low
Quarry; MQ, Marmot Quarry; RQ, Red Quarry; CQ, Carter Quarry.

tained. The bulk of the microvertebrate fossils came from narrow,
sandy and pebbly strata in the clay bed, and when these were worked
out, no additional fossils of value were obtained. The quantity of
matrix processed by the Carters is unknown, but Midwestern Univer¬
sity collected approximately 10 tons. Large mammals from this quarry
include the bone-eating dog and giant camel. Preservation of fossils is
excellent, and the surface of bones is usually slick, hard, and white.

Marmot Quarry .—About 50 yards north of Meade’s Quarry 3. No
important microvertebrates were found, but the site was rich in re¬
mains of larger mammals. Part of the jaw of a giant ground squirrel,
the skull of a camel, and other specimens were obtained here, about
15 feet above the contact with the Bridwell Formation.

DALQUEST— BLANCO LOCAL FAUNA. TEXAS

9

Acknowledgments

I am indebted to the late J. S. Bridwell for the original permission
to collect and work in the Blanco. Following Mr. BridwelFs death,
Mr. Clifford Tinsley, of Wichita Falls, continued this permission. Mr.
Bobby Adams, Manager of the Bridwell Hereford Ranch at Cros-
byton, extended numerous courtesies during the years of work on the
ranch. Dr. Travis White, President of Midwestern University, encour¬
aged this work, and Financial support was granted from Midwestern
University research funds. Over the years, many graduate and under¬
graduate students aided in field work, especially the hard labor in¬
volved in gathering, transporting and washing more than 100 tons
of matrix from which the microfossils were obtained. I wish to thank
all of these people, and especially the following, who spent weeks
working with me in the field: Frank Judd, Richard Palmer, Edward
Roth, Joseph Stone, Wayne Seifert and Robert Westmoreland. Mrs.
Rose Carpenter aided in both the field work and preparation of
materials.

Dr. Wann Langston, of the Texas Memorial Museum, permitted me
free access to the material collected at the Blanco by Meade and
Evans, and allowed me to use comparative materials in the University
of Texas collections. Dr. Ernest Lundelius, University of Texas, and
Dr. S. David Webb, University of Florida, made helpful suggestions
in the course of this work, and Dr. Gerald Schultz, West Texas State
University, gave especially valuable help in detailed criticisms of the
manuscript, based partly on his own knowledge of the Blanco. Dr.
Craig C. Black, Texas Tech University, made available to me the
Blanco materials in his charge and aided greatly in the preparation of
this report.

Above all, I am indebted to the late Dr. Claude W. Hibbard, Uni¬
versity of Michigan. Dr. Hibbard allowed me free use of the Blancan
age materials he had assembled at the Museum of Paleontology and
aided in the identification of many of the specimens. His insistence
that the Blanco would eventually furnish a vertebrate microfauna,
and of the importance of fitting the Blanco local fauna into the
Blancan sequences, as well as his aid and encouragement in the long
and often discouraging work, is largely responsible for the completion
of this project.

Methods

Synonomies in the following species accounts deal primarily with
the Blanco, or involve major name changes. All catalogue numbers are

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those of The Museum, Texas Tech Univ. (TTU-P) except those of the
University of Texas (TMM), and Midwestern University (MU). Ab¬
breviations for Midwestern University quarries are: RQ (Red Quarry),
LQ (Low Quarry), MQ (Marmot Quarry), and CQ (Carter Quarry).
Measurements of specimens are in millimeters, and, when diameters
of bones or teeth are involved, the first measurement is anteropos¬
terior diameter; the second, transverse diameter (as 13.5 X 8.4).

Order Insectivora
Family Soricidae
Sorex taylori Hibbard

1938. Sorex taylori Hibbard, Trans. Kansas Acad. Sci., 40:242. Holotype
from the Rexroad local fauna of Kansas.

Referred specimens .—Anterior end of lower jaw with I-Mi (TTU-P 6129,
LQ); edentulous lower jaw (TTU-P 6130, RQ).

The articular condyles, processes, foramina and fossae of the man¬
dible are like those of Sorex taylori, and the size and characters of
the teeth, as far as they can be compared, resemble those of 5. taylori
Unfortunately the teeth of TTU-P 6130 are missing, but the size of
the alveolus of M 3 suggests a small tooth, like the M 3 of S. taylori.

S. taylori is known from the Rexroad local fauna, of Kansas, and
the Beck Ranch local fauna of Scurry County, Texas (Dalquest,
19726). It seems to be a widespread species of the early Blancan. It is
the only kind of shrew so far found in the Blanco.

Family Talpidae

Hesperoscalops blancoensis new species

Holotype. —Fragment of right lower jaw, TTU-P 6131, with well-
preserved Mi-M 3 , broken off just anterior to Mi and posterior to M 3 .

Type locality. —Carter Quarry, the same as or very close to Univer¬
sity of Texas Quarry 17 (Meade, 1945, fig. 1), Blanco Formation,
Blanco local fauna, Crosby County, Texas.

Distribution. —Known only from the Blanco Formation of Crosby
County, Texas.

Diagnosis. —A mole larger than Scalopus aquaticus Linnaeus, with
M 3 distinctly reduced in size as compared with M 2 and with very
strongly developed basal accessory cusps, especially on M 3 .

Referred specimens .—Upper right jaw fragment with M 3 , from
the Low Quarry (TTU-P 6132); jaw fragment, two humeri, isolated
lower Mi, from the Carter Quarry (TTU-P 6619-6621, 6133); iso¬
lated lower M 3 from the Red Quarry (TTU-P 6134).

DALQUEST—BLANCO LOCAL FAUNA, TEXAS 11

Description .—The holotype is beautifully preserved, and the teeth
are only lightly worn. It represents a mole similar to Hesperscalops
rex roadi Hibbard, the type species for the genus, but differs in larger,
broader teeth, M 3 markedly reduced as compared with M 2 , rather
than almost the same size, and basal accessory cusps of molars better
developed, especially on M 3 .

Hesperoscalops sewardensis Reed, the only other known species of
the genus, is very similar to but much larger than either H. rexroadi
or H. blancoensis. Reed (1962) emphasized the large size of the basal
accessory cusps of H. sewardensis. Dr. Claude Hibbard has kindly
loaned to me the holotype of H. sewardensis and much of his H.
rexroadi material, including the lower jaw with M 1 -M 3 from Fox
Canyon (Hibbard, 1953). The basal accessory cusps of the holotype
of H. sewardensis are larger than those of H. rexroadi, but the entire
dentition is larger. Relatively, the basal accessory cusps of H.
sewardensis are but little larger than those of H. rexroadi. Hespero¬
scalops blancoensis is only slightly larger than H. rexroadi but has
relatively much larger basal accessory cusps, especially on M 3 .

Discussion .—Moles of the genus Hesperoscalops are very poorly
known. H. sewardensis is known only from the holotype, a frag¬
mentary lower jaw. H. rexroadi is known from several lower jaw
fragments, an upper jaw fragment, isolated teeth and some skeletal
elements listed but not described (Hibbard, 1953). Available also is
a quantity of material from the Beck Ranch of Scurry County, Texas,
that includes lower jaw fragments, isolated teeth, and a number of
postcranial elements, as yet all undescribed. Classification must neces¬
sarily be based on the lower jaw fragments and teeth.

Hesperoscalops has very high-crowned teeth that change markedly
in occlusal aspect with wear, and this must be taken into account in
making comparisons. Diagnostic characters include the relative and
actual size of the teeth and jaw, relative size of M 3 as compared with
M 2 , and development of the accessory basal cusps of the molars. These
have been described by Hibbard (1941). There is no basal accessory
cusp on the posterior face of the talonid of M 3 . The anterior edge of
the trigonid of M 3 is strongly oblique to the transverse plane of the
ramus, but the posterior face of the talonid of M 2 is less so, and
there is a triangular gap between M 3 and M 2 . Further, the molars are
well separated in the toothrow, as is true of moles generally. The
basal accessory cusps rise from the cingula and flare outward to close
the spaces between the molars at about half the height of the unworn
teeth. The basal accessory cusp on the trigonid of M 2 must addition¬
ally close the triangular gap between the posterolingual edge of M 2

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Fig. 2 .—Hesperoscalops blancoensis: holotype, right lower jaw (TTU-P
6129) fragment in labial, occlusal, and lingual views. For measurements see

text.

DALQUEST—BLANCO LOCAL FAUNA TEXAS

13

and the anterolingual edge of M 3 . It is a relatively huge, flared shelf,
larger than the other basal accessory cusps. On all lower third molars
of Hesperoscalops rexroadi seen, the cusp of M 3 is relatively small.
All teeth were well worn to greatly worn, and it is not known how
much wear reduces the size of the shelflike cusp. The basal acessory
cusp of the M 3 of H. blancoensis is both relatively and actually huge
as compared with that of H. rexroadi. It is probable that, when more
complete specimens of the several kinds of Hesperoscalops are dis¬
covered, greater differences between the species will become obvious.

Hibbard (1953) considered Hesperoscalops ancestral to the modern
eastern mole, Scalopus. Scalopus has no basal accessory cusps or, at
best, only a faint trace of them (in 30 Recent specimens from north-
central Texas). In Scalopus, the M 3 is reduced in size as compared
with Mg. If development of basal accessory cusps is primitive, Hes¬
peroscalops blancoensis is more primitive than H. rexroadi. If reduc¬
tion of M 3 is advanced, H. blancoensis is more advanced than H.
rexroadi.

Etymology .—The species is named for the Blanco Formation.

Order Chiroptera
Bat, near Tadarida

In a sample of matrix taken in a pebbly band in the sand between
Meade’s Quarry 6 and Quarry 3, about 3 meters above the bottom
of the Blanco sediments, a single M 2 of a bat (TTU-P 6135) was
recovered, along with one cotton rat tooth. The site was judged un¬
worthy of further collecting effort, but the bat tooth is the only evi¬
dence of Chiroptera in the Blanco local fauna. The tooth is well
preserved and resembles the lower second molar of the modern
Tadarida brasiliensis.

Order Edentata
Family Glyptodontidae

Glyptotherium tcxanum Osborn

1903. Glyptotherium texanum Osborn, Bull. Amer. Mus. Nat. Hist., 19:492.

Holotype from the Blanco.

Referred specimens. —Two scutes (TTU-P 6136-6137, CQ), and material at
the University of Texas (Meade, 1945).

The holotype consisted of “the nearly complete carapace, pelvis,
sacrum, caudals, and complete tail armature of an individual in fine
preservation.” Curiously, Osborn did not give the source of the speci-

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men, other than saying it came from “the lower Pleistocene of
Texas,” and was obtained by an expedition under the direction of
J. W. Gidley. Gidley (1903h) included Glyptotherium texanum in his
faunal list and later (Gidley, 1926) definitely stated that the type
came from the Blanco Formation. Meade (1945) reported scutes of
this glyptodon from several different quarries, but fossils are un¬
common. The relationships of G. texanum and other glyptodonts
known from the United States are presently under study by Dr.
David Guillett.

Family Megalonychidae

Megalonyx leptostomus Cope

1893. Megalonyx leptostomus Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 49.

Holotype from the Blanco.

Referred specimens .—Four isolated cheek teeth (TTU-P 6138-6140, 6668, all
RQ); lower jaw fragment with three teeth and two isolated teeth (TMM 31171-
19); eight isolated teeth (TMM 31196-5).

The holotype consists of both premax ill aries, skull fragments, and
an upper tooth of a single individual. Meade (1945) has figured the
edentulous lower jaw of a specimen (TTU-P 438) from the Blanco,
with the characteristic symphysis of the genus.

There are numerous nominal species of Megalonyx, but it is
probable that only a few are valid. M. leptostomus, as the earliest-
named Blancan species, is probably valid. It is unfortunate that it is
so poorly understood.

The lower jaw at the University of Texas has three teeth in
place. The caniniform tooth is straight, laterally compressed, and, in
cross section, the external face is smoothly curved, the internal face
more straight but convex medially. The second (anterior molariform)
tooth is quadrate and measures 16.4 X 20.3. The second molariform
tooth is also quadrate but markedly broader lingually than labially.
It does not, however, have a triangular or “L” shape. It measures
14.8 X 22.4.

Catalogued under the same number (TMM 31171-19) are two
isolated molariform teeth of the same size, appearance, and nature of
preservation as the teeth in the jaw. One tooth is quadrate, measuring
16.0 x 20.8, and is probably the posterior tooth of the jaw. The other
tooth is somewhat triangular in cross-section, but with the hypotenuse
concave. It is probably an upper tooth.

Among the isolated teeth, some are of the lower jaw, including two
caniniforms and an anterior molariform. One tooth at the University
of Texas is a large, curved tusk, narrowly triangular in cross section;

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

15

Fig. 3. — Glossotherium near chapadmalense , upper incisor (TTU-P 6142)
and lower incisor (TTU-P 6144), in lateral views. These are isolated teeth,
shown in occlusal aspect, and are not necessarily from one individual.

Fig. 4 .—Glossotherium near chapadmalense , lower posterior molariform
tooth (TTU-P 6147), occlusal view.

it is probably the upper caniniform. TTU-P 6139 is smoothly oval in
cross-section and gently curved in lateral view. It may be the anterior
upper molariform. The other teeth are quadrate but sometimes
broader on one side than the other, not triangular.

Family Myi.odontidae
Glossotherium near chapadmalense

Referred specimens .— Nine isolated teeth (TTU-P 6141-6149, all RQ).

At the Red Quarry, in the lowermost part of the diatomite layer
and the underlying sandy silt, crushed, powdered bone fragments
indicated that a quantity of bone had disintegrated there. From
this 1 was able to recover the listed teeth, representing two (possibly
but not likely more) individual Glossotherium. TTU-P 6141-6143 are
long, curved upper caniniform teeth and TTU-P 6144 is a straight,
lower caniniform tooth. The upper caniniform teeth resemble the
incisors of a giant rodent. The most characteristic teeth are the pos¬
terior lower molariforms, TTU-P 6145-6146. They are extremely
complicated in cross-sectional shape, more so than any teeth figured
by Stock (1925) from the Rancho La Brea of California. TTU-P 6147
may be an upper first molariform tooth, and TTU-P 6148 and TTU-P
6149 are lobate teeth of uncertain position.

The above teeth have been examined by Dr. David S. Webb, of the
University of Florida, who remarked on their similarity to teeth of
Glossotherium chapadmalense from a Blancan age site (Haile XVA)
in Florida.

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Order Lagomorpha
Family Leporidae

Hypolagus sp.

Referred specimens .—Lower P 3 (TTU-P 6150), upper P 2 (TTU-P 6151, LQ).

The lower premolar is definitely of Hypolagus , and is from a small
rabbit. It measures 2.5 X 2.3. The anteroextemal valley is deeper
than in other specimens of Hypolagus of which 1 have found descrip¬
tions or seen specimens; it is nearly as deep as the posteroexternal
valley. The tooth may represent a variant of Hypolagus regalis Hib¬
bard or an unnamed species. The enamel of both valleys is wrinkled
but not crenulated.

The upper premolar is small and simple, with a small labial and a
large, open, anterior valley. The tooth could belong to Pratilepus, but
there is no other evidence of this genus in the Blanco local fauna.

Meade (1945) listed the upper cheek tooth of a rabbit as Hypolagus
but the tooth is not identifiable even to genus. The tooth is 4.8 wide
and from a rabbit larger than the teeth listed above.

The Midwestern University collection contains numerous frag¬
mentary and complete isolated rabbit teeth, including first and second
upper incisors, and upper and lower cheek teeth. These are not
identifiable, even to genus.

Nekrolagus cf. progressus Hibbard

1939. Pediolagus progressus Hibbard, Amer. Midland Nat., 21:512.

1939. Nekrolagus progressus Hibbard, Amer. Midland Nat., Table of Contents,
May 1939. Substitute name for Pediolagus , preoccupied.

Referred specimens .—Three P 2 's, one P 3 (TTU-P 6473-6476, LQ).

The lower premolar measures 3.2 X 2.7 and has a small anterior
valley and an isolated lake. Two of the upper premolars are clearly
of this genus, with three distinct, moderately large anterior valleys.
Both teeth measure 1.6 X 3.2; in one tooth the enamel of the valleys
is crenulated, whereas in the other it is not.

A third upper premolar is hesitantly referred to Nekrolagus. There
is a small but distinct lingual valley, a very deep anterior (median)
valley that turns strongly to the labial side of the tooth, and an in¬
dented, crenulated area in place of a labial valley.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

17

Order Rodentia
Family Sciuridae

Paenemarmota barbouri Hibbard and Schultz

1948. Puenemarmota barbouri Hibbard and Schultz, Univ. Nebraska Mus.
Bull., 3:19. Holotype from the Rexroad Formation, Meade County,
Kansas.

Referred specimens .—Anterior end of lower jaw with incisors and sym¬
physis (TTU-P 6156, MQ); isolated incisor (TTU-P 6157, CQ), lower incisor
{TMM 1176-65), and a fragmentary ramus with part of M 2 and M 3 (TMM
31179-52).

Meade (1945) reported an incisor of the giant ground squirrel
(TMM 31176-65) as a beaver tooth ( Procastoroides sp.). Three years
later, the giant ground squirrel was named, and Meade sent the speci-
ment to Hibbard (1950:136-137), who corrected the original identifi¬
cation and also described the jaw fragment. Subsequent authors have
sometimes overlooked Hibbard’s note and included both Paenemar-
mota and Procastoroides as members of the Blanco local fauna. No
beaver has been found at the Blanco.

Spermophilus sp. large

Referred specimens .—Fragment of maxilla with alveolus of P 3 and well-
preserved P 4 (TTU-P 6158), isolated upper P 4 (TTU-P 6159), 10 isolated teeth
(TTU-P 6160-6165, 6612-6615), all LQ; five isolated teeth (TTU-P 6166-6169,
6265, CQ); four isolated teeth (TTU-P 6170-6173, RQ).

The teeth include worn, slightly worn, and unerupted teeth that
are mere enamel caps. It is impossible to place some of these teeth in
the toothrow. Two upper fourth premolars bear strong resemblance
to teeth of Spermophilus variegatus, a species living in Texas today.
All of the teeth differ from S. variegatus in being broader transversely
and more slender anteroposteriorly.

Many species of ground squirrels have been described from Blancan
faunas of the United States. The larger Blanco teeth may be in the
size range of S. bensoni (Gidley) from Arizona, S. rexroadensis (Hib¬
bard) from Kansas, and S. finlayensis (Strain) from far western
Texas. Good lower jaws are required for identification.

Spermophilus sp. medium size

Referred specimens .—Five isolated teeth (TTU-P 6174-6178, LQ), five iso¬
lated teeth (TTU-P 6179-6183, CQ), seven isolated teeth (TTU-P 6185-6189,
6154-6155, RQ).

The teeth are from a species of ground squirrel about the size of S.
mexicanus (Erxleben), which lives in the area today, and larger than

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

S. howeHi (Hibbard), from the Rexroad local fauna of Kansas. The
cusps and lophs are rather simple. Identification of this species must
await the discovery of better material, preferably a good lower jaw.

Spermophilus cf. howelli (Hibbard)

1941. Citellus howelli Hibbard, Amer. Midland Nat., 26:347. Holotype from
the Rexroad Formation of Meade County, Kansas.

Referred specimens .—Four teeth (TTU-P 6190-6193, RQ).

The teeth are the size and have the appearance of teeth of Spermo¬
philus howelli. This is the smallest species of ground squirrel in the
Blanco collection, and was found only at the Red Quarry. The teeth
are approximately the size of teeth of the living Spermophilus
spilosoma.

Family Geomyidae
Geomys sp.

Referred specimens .—Numerous teeth (TTU-P 6194, 6596-6611, LQ, TTU-P
6195, 6152-6153, 6666-6667, 7492-7499, RQ, TTU-P 6196, 6529-6595, LQ);
fragmentary skull (TTU-P 6197, CQ).

Teeth of pocket gophers are outnumbered only by teeth of cotton
rats in the Blanco deposits. Upper and lower premolars and molars
were found at all three quarries in about equal numbers. Among the
specimens purchased from the Carters is the anterior end of a skull
with the two incisors still in place in the matrix, but without cheek
teeth. In the entire Blanco collection there are no lower jaws.

Incisors and cheek teeth are all from gophers of approximately the
same size. The upper incisors have the typical Geomys bisulcate
pattern. The teeth suggest animals smaller than the modern Geomys
bursarius and about the size of some of the smaller races of the living
Thomomys. Dentine tracts are developed on the cheek teeth as in
Geomys . However, several lower third molars are from immature
animals and these show that the unworn enamel cap is longer, and
descends farther on the crown, than is the case in modern Geomys
bursarius of comparable age.

Among the teeth, a lower molar and an upper third molar have the
roots closed. Two other molars have the roots markedly constricted
and are clearly in a process of closing. In one premolar and several
other molars, the root canal is narrowed by a uniform constriction,
and further normal growth of these teeth would be unlikely. In most
of the teeth, the roots are open, in typical Geomys fashion. The teeth
may represent two species of pocket gophers, but it is equally likely

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

19

that the teeth with constricted or closed roots are from senile indi¬
viduals. The Blanco Geomys may have developed closed roots on the
cheek teeth only late in life. Hibbard (1967) noted that the transtition
from pocket gophers with rooted cheek teeth to ever-grow ing cheek
teeth occurred in pre-Blancan or earliest Blancan times. The ten¬
dency toward closure of the roots in the Blanco specimens may repre¬
sent a persistently primitive character.

Hibbard ( loc . cit .) gave a detailed account of the pocket gophers
of the upper Pliocene and lowest Pleistocene of Kansas, and it is ob¬
vious that at least a complete jaw is required for specific identification
of these rodents. The Blanco gopher is probably an undescribed
species, but identification must aw r ait collection of better material.

Family Heteromyidae

Perognathus cf. rexroadensis Hibbard

1950. Perognathus rexroadensis Hibbard, Contrib. Univ. Michigan Mus.
Paleontol., 8:140. Holotype from the Rexroad Formation of Meade
County, Kansas.

Referred specimens .—End of rostrum with incisors (TTU-P6198, CQ),
numerous isolated teeth and several fragmentary jaws (TTU-P 6199-6200,
6479, 6516-6527, CQ and TTU-P 6477-78, LQ. TTU-P 6528, RQ).

The material was compared directly with topotypes of Perognathus
rexroadensis , and no significant differences were detected. It should
be noted, however, that teeth and jaws of Perognathus offer few char¬
acters, other than actual and relative size of teeth, that are diagnostic
at the specific level. Pocket mice arc common mammals of the deserts
and arid plains of southwestern United States and adjacent Mexico
today, and more than two species often occur together. The morpho¬
logical differences between these sympatric species often do not ex¬
tend to teeth and jaws, the only parts usually found as fossils. It
is possible that the specimens from the Blanco actually represent a
species different from P. rexroadensis.

Perognathus cf. pearlettensis Hibbard

1950. Perognathus pearlettensis Hibbard, Contrib. Univ. Michigan Mus.
Paleontol., 8:139. Holotype from the Rexroad Formation of Meade
County, Kansas.

Referred specimens .—Lower jaw with P 4 (TTU-P 6201, CQ), maxillary
fragment with P 4 -M 2 (TTU-P 6202, RQ); maxillary fragment with P 4 (TTU-P
6203, CQ); numerous isolated teeth (TTU-P 6204, 6461-6472, LQ; TTU-P
6205, 6432-6448, CQ; TTU-P 7143. 6497-6498, 6487-6494, LQ).

The small pocket mouse is only slightly less common than the large
P. rexroadensis but is represented by fewer jaws. The specimens have

20

OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

been compared directly with topotypes of P. pearlettensis and are
very similar but seem to average a trifle smaller.

Prodipodomys centralis (Hibbard)

1941. Liomys centralis Hibbard, Amer. Midland Nat., 26:349. Holotype from
the Rexroad Formation, Meade County, Kansas.

1954. Prodipodomys rexroadensis Hibbard, Trans. Kansas Acad. Sci., 57:228.

Holotype from the Rexroad Formation of Meade County, Kansas.

1972. Prodipodomys centralis Hibbard, in Skinner ei ul.. Bull. Ainer. Mus.
Nat. Hist., 148:88.

Referred specimens. —Lower jaw with P< and M 2 *M 3 (TTU-P 6207, LQ); and
numerous isolated teeth (TTU-P 6208, 6235-6237, LQ; TTU-P 6495-6496,
RQ).

Kangaroo rats were taken only at the Low and Red quarries. The
roots of the premolars are strongly developed and there are no den¬
tine tracts on the sides of the molars. The teeth are moderately hypso-
dont and resemble teeth of Prodipodomys centralis in detail. One iso¬
lated molar is from a very young animal and, like the holotype, closely
resembles lower molars of young spiny pocket mice, Liomys.

Family Cricetidae
Peromyscus near kansasensis Hibbard

1941. Peromyscus kansasensis Hibbard, Amer. Midland Nat., 26:352. Holotype
from the Rexroad Formation of Meade County, Kansas.

Referred specimens. —Maxillary fragment with M*-M 2 (TTU-P 6209, LQ);
M 1 (TTU-P 6210, LQ); two M 3 (TTU-P 6211-6212, CQ).

The teeth are the size of those of Peromyscus kansasensis, but a
lower jaw will be required for reliable identification. The few speci¬
mens do show the presence of a large deer mouse in the fauna.

TTU-P 6212 (CQ) is a lower third molar of a much smaller kind of
Peromyscus or a Bensonomys.

Reithrodontomys sp.

Referred specimen .—Isolated upper first molar (TTU-P 6213, LQ).

Hibbard (personal communication) examined this tooth and re¬
ferred it to Reithrodontomys, stating “lingual root not as broad
anteroposteriorly as in Baiomys. It has no labial root as in R.
megalot is or R. montanus, or most fossil forms I have.”

Baiomys sp.

Referred specimen .—Upper first molar (TTU-P 6214, CQ).

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

21

Baiomys is known from several Blancan local faunas. The single
tooth is not specifically identifiable.

Bensonomys sp.

Referred specimen .—Upper first molar (TTU-P 6215, CQ).

Bensonomys is a typical Blancan genus, known from numerous
Blancan local faunas. The genus is extinct. The single tooth is not
specifically identifiable.

Onychomys sp.

Referred specimen .—Upper first molar (TTU-P 6216, CQ).

The tooth is from a very small species of grasshopper mouse,
smaller than the living O. leucogaster or O. torridus. Dr. Hibbard has
examined the specimen and remarked that it is the size of the smallest
Onychomys gidley i Hibbard, from the Rexroad Formation of Kansas.
Reference to a species on the basis of one tooth is impractical.

Neotoma cf. quadriplicatus (Hibbard)

1941. Parahodomys quadriplicatus Hibbard, Amer. Midland Nat., 26:356.

Holotype from the Rexroad Formation of Meade County, Kansas.

1967. Neotoma quadriplicatus, Hibbard, Papers Michigan Acad. Sci., Arts and
Letters, 52:125.

Referred specimen .—Lower second molar (TTU-P 6217, LQ).

The enamel is thick, and the pattern is typical of woodrats from the
Rexroad Formation of Kansas and the Beck Ranch local fauna of
Scurry County, Texas. Scarcity of woodrats in the Blanco may indicate
scarcity of cliffs and talus in the vicinity when the deposits were
forming.

Sigmodon medius Gidley

1922. Sigmodon medius Gidley, U.S. Geol. Surv, Prof. Papers, 131:126.
Holotype from the Benson local fauna of Arizona.

Referred specimens .—Lower jaw fragment and 43 isolated teeth (TTU-P
6218-6234, 6238-6264. RQ); numerous isolated teeth from CQ (TTU-P 6266,
6480-6486) and LQ (TTU-P 6267. 6449-6460).

The little cotton rat is almost ubiquitous in the Blanco sediments.
Nearly every prospect site, if it yielded microvertebrate fossils at all,
had Sigmodon . Usually, the cotton rat was the only species present.
Dr. Claude Hibbard and Dr. Robert A. Martin have examined teeth
from the Blanco and agree that the species is S, medius.

22

OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

Order Carnivora
Family Canidae

Canis lepophagus Johnston

1938. Canis lepophagus Johnston, Amer. J. Sci., 5th ser., 35:383. Holotype
from the Cita Canyon local fauna of Texas.

Referred specimens. —Lower jaw fragment with P 3 -P 4 . held together largely
by matrix (TTU-P 6268) and numerous isolated teeth (TTU-P 6209), all RQ;
tibia lacking the proximal end (TTU-P 6270), pick-up on surface.

Canis lepophagus is the Blancan ancestor of the modem coyote.
The differences between the known specimens and equivalent parts of
the modem coyote are numerous but minor (Bjork, 1970), and
isolated teeth are not identifiable.

Meade (1945) predicted the presence of Canis in the Blanco local
fauna, but the only material thus far obtained includes the listed teeth,
belonging to at least one puppy and one adult, recovered in the lower
part of a thick layer of diatomite. Bone associated with the teeth had
been crushed flat and reduced to a powder. The tibia is of a mature
coyote but is small. Hibbard (personal communication) found it
slightly smaller than any coyote tibias at the University of Michigan,
and the bone is smaller than that of any of 25 skeletons in the Mid¬
western University collection, although some female skeletons have
tibias nearly as small.

Borophagus diversidens Cope

1892. Borophagus diversidens Cope, Proc. Acad. Nat. Sci. Philadelphia, 44:326.
Holotype from the Blanco.

Referred specimens. —A skull, jaws and partial skeleton (MU 8034) of a
young adult from the Carter Quarry, isolated bones and teeth (Dalquest, 1969:
118 ).

The above material has been described elsewhere (Dalquest, 1969),
and the taxonomic history and status of the species discussed.

The big bone-eating dog must have been common when the Blanco
deposits were forming. A number of uncatalogued scraps from other
quarries attest to the distribution of the species throughout the de¬
posits. The countless thousands of chips and fragments of bone from
horses, camels, and other large mammals seem to have been derived
largely from the feeding of Borophagus. In every quarry, many bone
chips bear distinct marks made by the teeth of large scavengers,
doubtlessly mainly Borophagus.

DA LQUEST—BLANCO LOCAL FAUNA, TEXAS

23

Family Mustelidae

Canimartes cumminsi Cope

1893. Canimartes cumminsti Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 52.
Holotype from the Blanco.

Canimartes cumminsi was a moderately large mustelid. The holo¬
type includes the posterior parts of a skull with jaws and molar teeth
(Cope, 1893), parts of which are still preserved in the collection of the
University of Texas. Other forms and specimens have been referred
from time to time to the genus Canimartes but later removed to other
mustelid genera (Gazin, 1937; Zakrzewski, 1967). Canimartes seems
to be a monotypic genus, still known only from the holotype.

Spilogale rexroadi Hibbard

1941. Spilogale rexroadi Hibbard, Amer. Midland Nat., 26:342. Holotype from
the Rexroad Formation of Meade County, Kansas.

Referred specimens .— Lower jaw fragment with Mi (TTU-P 6271 CQ),
upper M‘, canine and incisor (TTU-P 6272-6274 CQ), probably belonging to
one individual.

This diminutive spotted skunk was described from the Rexroad
local fauna of Meade County, Kansas, and later reported (Dalquest,
1972a) from the late Pliocene Beck Ranch local fauna of Scurry
County, Texas. The Blanco specimens are tiny, but are a trifle larger
than the holotype and Scurry County teeth. The lower camassial is
5.7 long, versus 5.2 for the holotype and 5.6 for each of the Scurry
County specimens. Other Kansas teeth range from 5.3 to 6.0 in
length. The upper first molar measures 4.1 along the labial edge,
versus 3.8 in the upper molar from the Beck Ranch, and 5.4 wide
versus 4.9 in the Beck Ranch tooth. The upper molar is also a bit
more “notched” on the labial edge, and more constricted medially, but
these features are variable in spotted skunks. The teeth of Spilogale
rexroadi are smaller than those of living forms of Spilogale, other
than the tropical species, S. pygmaea Thomas. The Blanco is the third
record station for the species.

Family Hyaenidae

? Chasmaporthetes johnstoni (Stirton and Christian)

1940. Ailuraena johnstoni Stirton and Christian, J. Mamm., 21:445. Holo¬
type from the Cita Canyon local fauna of Texas.

1941. Chasmaporthetes johnstoni Stirton and Christian, J. Mamm., 22:198.
(Ailuraena referred to genus Chasmaporthetes Hay).

Referred specimen ,—Upper first molar (TTU-P 6275, RQ).

24

OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

The upper molars of Chasmaporthetes are unknown, but the re¬
ferred tooth is utterly different from that of any known North Ameri¬
can carnivores. It most closely resembles the upper first molars of
some of the Old World viverrids, such as the larger mongooses. The
tooth is much larger, of course, measuring about 8.9 X 17.4. The
crown is somewhat eroded, which makes exact measurement diffi¬
cult. One external root, presumably the posterior, is smaller and more
lingually placed than the other external root, and the tooth is pre¬
sumably from the right side of the jaw. The tooth shows moderate
wear, and the kind of wear is like that exhibited in mongooses with
moderately worn teeth.

Family Felidae
Felis cf. lacustris Gazin

1933. Felis lacustris Gazin, J. Mamm., 14:251. Holotype from the Hagerman
local fauna of Idaho.

Referred specimens .—Ulna lacking top of olecranon (TTU-P 6276, RQ),
radius (TTU-P 6277, MQ), and left second metacarpal (TTU-P 6278, MQ).

Felis lacustris was a cat intermediate in size between the puma and
the lynx. It is known from numerous specimens representing much of
the skeleton from Idaho (Bjork, 1970), and is also recorded from the
Rexroad local fauna of Kansas. There are specimens from the Beck
Ranch local fauna of Texas in the Midwestern University collection
that closely match the fossils from the Blanco. The radius of F.
lacustris is uniquely straight and flat anteriorly, as noted by Bjork
(1970), a character shared by the radii from the Beck Ranch and the
Blanco. Without dentitions, however, the identity of the Blanco cat
must remain provisional.

The metacarpal resembles that of a puma but is very straight.
Measurements are: greatest length, 96.3; proximal end, 15.0 X 8.9;
midshaft, 10.2 X 8.5; distal end, 13.1 X 11.8.

Felis (Dinofelis) palaeoonca Meade

1945. Panthera palaeoonca Meade, Univ. Texas Pub!., 4401:521. Holotype
from the Blanco.

Referred specimens .—Left fourth metatarsal lacking distal tip (TTU-P 6279)
and upper left carnassial (TTU-P 6280), both MQ.

The holotype is a skull and associated lower jaws. Meade noted
that the skull and mandible resembled those of the modem jaguar but
that the teeth were longer, especially the carnassial (Savage, 1960).

The isolated carnassial listed is beautifully preserved. It is about
the size of large jaguar camassials in the Midwestern University col-

DALQUEST—-BLANCO LOCAL FAUNA, TEXAS

25

Fig. 5 .—Felis (Dinofelis) palaeoonca Meade, upper left carnassial (TTU-P
6280) in labial view, showing ectoparastyle.

lection and a bit smaller than the carnassial of the holotype of F.
palaeoonca (30.0 versus 33.0 in holotype). The tooth differs markedly
from the upper carnassial of other large modern cats in the much
longer blade of the metacone (12,2), with the consequent shortening
of the anterior part of the tooth. There is also a distinct accessory
cusp (ectoparastyle) at the anterior external corner of the tooth
that is rare in modem jaguars.

The metatarsal is the size of the fourth metatarsal of a lioness, and
is referred to F. palaeoonca on the basis of its size. It is relatively too
slender to have belonged to a sabertooth cat. The proximal di¬
ameter is 19.4 X 15.4; midshaft 12.7 X 11.3.

Kurten (1972) has placed Felis palaeoonca in the Old World
genus, Dinofelis Zdansky. The relationship of F. palaeoonca to cats
presently placed in Dinofelis , as pointed out by Kurten, seems con¬
vincing. However, the magnitude of the differences separating Felis
from Dinofelis seems to be more on the order of those separating
subgenera than of those separating genera.

The flattened upper canine of P. palaeoonca seems to be distinc¬
tive, as is the elongated metacone of P 4 . However, an ectoparastyle,
lacking in the holotype of P. palaeoonca , is present in TTU-P 6280.
An ectoparastyle is present in some specimens of Panthera onca ,
con. Kurten (1972:4).

? Homotherium

Referred specimen .—Basal portion of a canine tusk (TTU-P 6281, MQ).

Only the basal half of the tusk was present. The greatest diameter is
29.0 X 13.6. The fossil compares closely with Ischyrosmilus and
Homotherium but is not actually identifiable. The base of the tusk

26

OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

is thicker and more curved than that of Machiarodus from the Coffee
Ranch local fauna (Hemphillian) of Texas.

Order Proboscidea

y Family Gomphotheriidae

Rhynchotherium praecursor (Cope)

1893. Tetrabelodon shepardii, Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 57
1893. Dibelodon praecursor Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 62.

1923. Rhynchotherium fatconeri Osborn, Amer. Mus. Novil., 99:1-4.

1935. Serridentinus praecursor, Osborn, Proc. Nat. Acad. Sci., 21:404-412.

1936. Serbelodon praecursor. Osborn, Proboscidea, 1:1-802.

1955. Mammut [praecursor], Johnston and Savage, Univ. California Publ,
Geol. Sci., 31:51-74.

1972. Serbelodon (?) praecursor, Skinner and Hibbard, Bull. Amer. Mus. Nat.
Hist., 148:1-148.

The presence of inferior-tusked mastodons in the Blanco has been
known since Cope (1893) figured a lower jaw and referred it to Tetra¬
belodon shepardii Leidy. The second molar of the jaw was greatly
worn and the third molar moderately worn. In the same paper, Cope
figured and described an unworn third lower molar of a mastodon,
lacking the anterior crest, as the holotype of a new species, Dibelodon
praecursor. Later, Osborn (1923) made the lower jaw figured by
Cope, the holotype of a new species, Rhynchotherium falconeri , and
this apparently has been accepted by all workers to the present time.
The isolated molar has had varied treatment. Osborn (1935) placed
it in the genus Serridentinus, but the following year changed his mind
and put it in Serbelodon, calling it an upper, not lower, third molar.
Johnston and Savage (1955:37) thought Cope’s Dibelodon praecursor
referable to the genus Mammut , sensu lato, but Skinner et al.
(1972) returned questionably to Osborn’s combination, Serbelodon
praecursor.

Thus, both the lower jaw and the isolated molar, figured and de¬
scribed by Cope more than 80 years ago, have ever since been placed
in separate genera and species. Actually, as a careful examination of
Cope’s figures shows, the isolated molar and the third molar in the
lower jaw are similar. The molar in the jaw is much worn anteriorly,
and figured one-half natural size. The isolated molar is figured full
size, and is unworn. However, it is apparent that the unworn molar,
when worn to the level of the occlusal surface of the molar in the jaw,
would have almost exactly the same size and enamel pattern. In May

1973, 1 was able to examine the type of Dibelodon praecursor at the
University of Texas and compare it with a cast of the holotype (jaw)
of Rhynchotherium falconeri. The molar of R. falconeri is a few

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

27

millimeters longer, a few millimeters broader anteriorly, more tapered
posteriorly, and narrower at the posterior end than is the molar of
D. praecursor. The differences are minor and scarcely obvious to the
naked eye. In both teeth, there were five crests, the anterior worn
away in the holotype of R. falconeri and broken away in that of D.
praecursor. In both teeth, the fifth crest consists of only two cusps.
In the holotype of R. falconeri , the two cusps are simple and of ap¬
proximately equal size. In the holotype of D. praecursor , the external
cusp is larger than the internal and would develop a trace of an an¬
terior spur when at the proper stage of wear. In the major crests, the
patterns of the two teeth are almost identical, both having simple
ectotrefoils and short transverse ridges lingually. The crests are high
and wedge shaped in lateral view. The valleys are deep, and at the
bottom of each valley, on the lingual side, is a single tiny tubercle.
In the holotype of R. falconeri, the tubercle between second and third
crests is the largest; in the holotype of D. praecursor , the tubercle be¬
tween the third and fourth cusps is the largest.

Cope (1893) stated that the holotype tooth of Dibelodon praecursor
had deposits of “cementum” in the valleys, and this statement was
repeated by Osborn (1936). This “cementum” has since been almost
completely removed but enough remains to show that it was the
smooth, marly, yellowish-tan material that occasionally adheres to
teeth and bones from the Blanco. For example, one camel jaw in the
Midwestern University collection is almost completely invested in the
material. It is an adventitious, inorganic deposit, not cementum.

The only differences separating the holotypes of Dibelodon prae¬
cursor and Rhynchotherium falconeri are minor details. The differ¬
ences are far less than one would expect in the range of variation in
a single species of proboscidian. The two nominal species represent a
single biological species, for which the proper name is Rhynchotheri¬
um praecursor (Cope).

Meade (1945) referred two molars (TMM 31177-1, 31177-23) to
Rhynchotherium falconeri, but Johnston and Savage (1955) referred
the same teeth to Mammut , sensu lato. I have studied these teeth.
They are right and left lower third molars, so similar in details that
they appear to be mirror images of each other. Doubtless, they are
teeth of a single individual. The teeth are enamel caps only, with den¬
tine undeveloped. There are four major crests, relatively high and
wedge shaped. The first four crests have simple trefoils externally
and short ridges internally. They are the size of, and have the enamel
pattern of, the holotypes of D. praecursor and R. falconeri. The only
differences of note are the presence of three cusps in the posterior
(fifth) crest rather than two and stronger development of the small

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

cusps in the lingual valleys. The differences are minor and well within
the range of variation to be expected in a species of proboscidian.

1 agree with Meade that these teeth are Rhynchotherium.

Osborn (1936) treated the Blanco mastodons in a hasty manner, as
noted by Meade (1945). In the account of Serbelodon praecursor ,
Osborn refigured three of Cope’s drawings. The caption stated that
the illustrations are of “three referred teeth from the Blanco of
Texas.” In fact, there are only two teeth, the two left-hand figures
being occlusal and lateral views of the same tooth. However the two
teeth do have simple ectotrefoils and the internal halves of the crests
are simple transverse ridges. Probably they are the second lower
molars of Rhynchotherium praecursor.

Although Cope (1893) referred these teeth, perhaps by accident or
error, to Dibelodon tropicus , it is clear that he intended a lower jaw
to be the holotype of that species. Thus Dibelodon tropicus is a syno¬
nym of Stegomastodon successor (Cope), not Rhynchotherium prae¬
cursor (Cope).

Stegomastodon mirificus Leidy

1858. Stegomastodon mirificus Leidy, Proc. Acad. Nat. Sci. Philadelphia,
10:11. Holotype from uncertain locality in Nebraska.

1892. Mastodon successor Cope, Proc. Acad. Nat. Sci. Philadelphia. 44:227.
Holotype from the Blanco.

1893. Dibelodon humboldtii, Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 62,
in pan.

1893. Dibelodon tropicus Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 62, in
part.

1924. Stegomastodon texanus Osborn, Amer. Mus. Novit., 154:3. Holotype
from the Blanco.

1936. Stegomastodon successor , Osborn, Proboscidea, vol. 1, American Mus.
Press, p. 671.

1955. Stegomastodon mirificus , Savage, Univ. California Publ. Geol. Sci.,
31:54.

Referred specimens .—Four lower jaws or jaw rami (TTU-P 6184, MU
7103, MU 7122, MU 8927); three fragmentary tusks (TTU-P 7203-7204, MU
8927); 15 isolated separately catalogued cheek teeth (TTU-P 6648-6662); and
numerous postcranial elements (all LQ). Also, material at the University of
Texas (see Meade, 1945:523-524).

Mastodons of this genus have relatively short jaws with a short,
down-turned, spoutlike groove for the tongue in the lower jaw sym¬
physis, lack lower tusks, and have slender, rounded, upper tusks with¬
out enamel. The cheek teeth are bunodont, the cusps, when unworn,
appearing as rounded cones. There are six or more transverse crests
on the third molars.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

29

The enamel pattern of the teeth is extremely variable. In the holo-
type of Stegomastodon successor (Cope), from the Blanco, the teeth
are quite simple, with simple trefoils and a few isolated, simple inter¬
mediate cones. In the holotype of Stegomastodon texanus Osborn,
also from the Blanco (Osborn, 1924), the enamel pattern of the molars
is extremely complicated. Meade (1945) stated that “the posterior
ridges and cones not only become progressively larger with advanc¬
ing age of the individual, but that posterior accessory conelets and
cones are added as well, during and after eruption of the tooth.”
Meade was referring, of course, only to the third molars, in which the
posterior part of the tooth is still deep in the jaw, and enamel might
still be formed here, while the anterior edge of the tooth has
erupted. It seems reasonable that some additional enamel might be
added to the posterior end of a third molar after the front edge is in
use, but more than this is involved. Some unerupted third molars have
extremely complicated enamel patterns, such as the M 3 illustrated by
Savage (1955) from Cita Canyon, Texas, and some teeth in the Uni¬
versity of Texas collection. Furthermore, a range of variation almost
equal to that seen in the third molars is seen also in M 1 and M 2 , and
in these short teeth, it is not possible that enamel might be added after
eruption.

Meade (1945) placed Stegomastodon texanus Osborn in the syn¬
onymy of Stegomastodon successor (Cope), and I agree that the
range of variation in teeth in Stegomastodon jaws and undoubted iso¬
lated Stegomastodon teeth from the Blanco encompasses the charac¬
ters of the two nominal species. Savage (1955), after a study of the
Stegomastodon material from the Cita Canyon local fauna, referred
all specimens from both Cita Canyon and the Blanco to Stegomasto¬
don mirificus (Leidy) described from Nebraska. I am following
Savage, with some hesitation. The species of Stegomastodon from the
middle Pleistocene of Texas, as from the Seymour Formation (Hib¬
bard and Dalquest, 1966), remains to be determined. It is probably
distinct from the Blanco species.

Stegomastodon is represented by good material from the Blanco.
In addition to the holotype jaws of S. successor and S. texanus, there
are two lower jaws with the cheek teeth of both sides and a jaw ramus
with the teeth and symphysis in the Midwestern University collection,
and Meade (1945) listed “several partial skulls and mandibles” in
the University of Texas collection.

Probably, some 100 or more isolated mastodon teeth from the
Blanco are preserved in collections. Those with very complicated
enamel patterns are doubtless Stegomastodon, and most of those with

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

simpler patterns probably are also. However, in view of the known
presence of mastodons other than Stegomastodon in the Blanco local
fauna, these teeth must be considered with caution.

The tusks of the Blanco Stegomastodon are known from a number
of specimens in the University of Texas collection and three in the
Texas Tech University collection. The tusks of the adult are relatively
small and slender, round in cross-section, and gently but uniformly
curved, and lack enamel. However, the tusk of an immature specimen
(MU 7122) found close to, and doubtless belonging to, the same
individual as does a lower jaw (MU 7103), has a small area of enamel
at the tip. The distal part of the tusk is curiously worn and abraded,
probably from contact with the trunk of the animal. The tip is worn
away in an irregular fashion, but enamel is present where the tusk had
a diameter of about one inch.

In the University of Texas collection is the tip (about four inches
long) of the tusk of a juvenile mastodon (TMM 31195-10). It is round
in cross-section and completely covered with enamel. This tusk too is
probably that of Stegomastodon , and it appears that Stegomastodon ,
like some other proboscidians without enamel on the tusk of adults,
had enamel-covered tusks when very young.

Undetermined mastodon material

Meade (1945) mentioned three lower third molars of mastodons
that he thought might be referable to a species of Rhynchotherium
but not R. falconeri ( R . praecursor). The identification of these and
some other mastodon teeth from the Blanco cannot be determined
until similar teeth are found in jaws.

One tooth germ (TTU-P 6663) deserves special mention. It is
probably an upper or lower second molar. The three major crests
are formed by slender, elongated cusps that appear almost fingerlike
in lateral view. Near their bases the cusps are somewhat wrinkled but
it is obvious that no true trefoil pattern would be formed with wear.
There are a few, small, intermediate conules between the large ex¬
ternal and internal cusps of each major crest. The fourth crest con¬
sists of a row of anteroposteriorly flattened, rather triangular, cusps
with strong posterior inclination. This crest forms a fringelike row,
bent away from the other crests. This tooth is certainly not Stego¬
mastodon and is probably not Rhynchotherium , although no teeth
other than lower third molars and the greatly worn M 2 in the holo-
type have been referred definitely to Rhynchotherium praecursor .
The crests are unlike the wedge-shaped crests of the genus Mammut.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

This tooth probably represents a kind of mastodon other than Stego-
mastodon or Rhynchotherium .

Also representing another kind of mastodon is a tiny tusk in the
University of Texas collection (TMM 3179-35). As preserved, the
tusk is 88 millimeters long, but the proximal part is broken away.
It is straight and round-oval in shape, and clearly is the inferior
tusk of a mature mastodon. The tip is worn flat, and at the wear facet
measures about 10 X 8. The distal 20 millimeters are covered by
heavy enamel but there is only dentine posterior to the abrupt termi¬
nation of the enamel. The tusk on one side, probably the medial side,
posterior to the enamel-covered tip, is worn by abrasion of the trunk
or tongue. The tusk is not from Rhynchotherium , which has a flat
inferior tusk covered with enamel on the upper side, or Stegomasto-
don, which has no inferior tusks.

There is evidence, then, that one or more kinds of mastodons other
than Rhynchotherium and Stegomastodon were part of the Blanco
local fauna, but identification must depend on discovery of lower jaws.

Order Perissodactyla
F amily Equidae

Nannippus phlegon (Hay)

1893. Equus minutus Cope, 4th Ann. Kept. Geol. Surv. Texas, p. 67. Holotype
from the Blanco.

1899. Equus phlegon Hay, Amer. Geol., 24:345-349. Replacement name for
E. minutus Cope.

1926. Hipparion (Nannippus) phlegon , Matthew. Quart. Rev. Biol., 1:139-185.
1936. Nannippus phlegon, Gazin, Proc. U.S. Nat. Mus., 83:281-320.

Referred specimens. —Lower jaws with complete dentition (TTU-P 6282,
RQ, figured by Dalquest and Donovan, 1973); left lower cheek-tooth series
(TTU-P 6283, RQ); associated right pz-P 4 , left P 2 -M 1 , (separately numbered
TTU-P 6284-6289, 6206, RQ); three associated upper teeth (TTU-P 6290,
RQ); two worn associated upper teeth (TTU-P 6293, RQ); 37 isolated upper
(TTU-P 6294-6330) and 34 isolated lower (TTU-P 6331-6362, 6291-6292)
cheek teeth; a few postcranial elements.

Cope (1893) Figured the tooth that is the holotype of the species,
and the tooth is still preserved in the collection of the University of
Texas. Matthew (1926) mentioned finding “skulls, feet, etc.” at the
Blanco in 1924. This material has never been figured. Dalquest and
Donovan (1973) figured an excellent pair of lower jaws from the
Blanco.

Nannippus phlegon seems to be the most highly specialized of the
late Pliocene and earliest Pleistocene species of Nannippus. All of

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

the more complete material and most of the isolated teeth came from
the diatomite layer of the Red Quarry or the lacustrine deposits im¬
mediately beneath it. Nannippus may have fed extensively on the suc¬
culent vegetation of reeds, grasses, and other semiaquatic species
inasmuch as most of the fossils found were associated with fossilized
remains of aquatic plants. Here, Nannippus was the most common
species of large mammal, although remains of Equus simplicidens
and ground sloths also were present. Elsewhere, remains of Nannippus
were rare.

Equus (Dolichohippus) simplicidens Cope

1892. Equus simplicidens Cope, Proc. Amer. Phil. Soc., 30:124. Hoiotype from
the Blanco.

1972. Equus ( Dolichohippus ) simplicidens, Skinner et at. , Bull. Amer. Mus.
Nat. Hist.. 148:1-147.

Referred specimens .—Six lower jaws with teeth, all more or less fragmentary
{TTU-P 6363-6364. CQ; TTU-P 6365-6366, R0; TTU-P 6367-6368, MQ), 23
upper (TTU-P 6369-6391) and 12 lower (TTU-P 6392-6403) cheek teeth; nu¬
merous postcrania] elements.

Cope (1893) reported that remains of this large horse were “abun¬
dant” in the Blanco, and it is true that scraps of horse teeth are widely
scattered in the deposits. This results in large part from the resistant,
hard nature of horse teeth. Complete bones and teeth are uncommon.
Matthew (1924a) mentioned two partial skeletons and a skull (briefly
described) from the Blanco; the skull, upper dentition, and limb bones
were figured later (Matthew, 1926). However Meade (1945) reported
only two maxillaries, a lower jaw fragment, and isolated teeth and
bones. The Midwestern University material includes only one lower
jaw ramus with well-preserved teeth. The others, and especially the
jaw fragments and teeth from the Red Quarry, are poorly preserved.

As compared with Pleistocene species of Equus , the teeth of E .
simplicidens are relatively short crowned. The highest of the 26 upper
cheek teeth measures, from the notch between the roots to the top of
the protocone, about 80 millimeters. A few show considerable curva¬
ture similar to, but less than, the curvature often seen in the upper
teeth of Pliohippus. The protocones are relatively short and wide but
are large. The upper dentition is quite PI iohipp us-\ike. In the lower
molars, the valley between the protoconid and hypoconid invariably
penetrates between the metaconid and metastylid. In the premolars,
the metaconid and metastylid are pillared. The valley between meta¬
conid and metastylid of the lower cheek teeth is usually V shaped or
flat bottomed with angular sides. It is not U shaped.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

33

Equus cumminsi Cope

1893. Equus cumminsli Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 67.

Holotype from the Blanco.

Referred sped me ns .—Upper M 3 (TTU-P 6407, MQ), lower cheek tooth
(TTU-P 6408, RQ), lower cheek tooth (TTU-P 6409, RQ), articulated phalanx
1 and 2 (TTU-P 6410, RQ).

This species was described from three broken upper teeth, two of
which were figured (Cope, 1893). Distinguishing characters are rela¬
tively small size (as compared to E. simplicidens) and simple enamel
lakes of the upper teeth. The teeth are low crowned and seemingly
from aged animals, although Cope {op. cit. y 67) claimed that the sup¬
posed diagnostic characters were not due to age, and were shown also
by the third, unfigured, specimen, with a crown 47 millimeters long.

Hibbard (1938) and Meade (1945) thought that the small size and
simple enamel pattern of the holotype teeth resulted from wear and
that the teeth were from aged individuals of small-sized Equus
simplicidens . However, Hibbard (1944) later abandoned this opinion
and referred a lower jaw of a horse from Kansas to Equus cf. cum-
minsii. Others (for example, Strain, 1966) have also referred speci¬
mens to this species.

Study of the Blanco horse material convinces me that there is a
species represented that is smaller than, and distinct from, Equus
simplicidens but still a primitive form of Equus. Some of the type
material of E. cumminsi still is preserved in the collection of the Uni¬
versity of Texas. The tooth marked “type” is the one figured by Cope
(1893, pi. 23, fig. 1). It is badly broken, weathered, and greatly worn.
The very simple enamel lakes described by Cope probably do result
from senility. However, the tooth is very small, anteroposterior length,
as preserved, 24.2 (measurement taken May 1973). It is scarcely
conceivable that a molar of E. simplicidens could be so small. Inas¬
much as there is better evidence of the presence of a small species of
Equus in the Blanco fauna, the tooth doubtless is a worn tooth of this
small species, and the name Equus cumminsi is valid.

In the University of Texas collection, there is a set of three lower
teeth (TMM 31166-3), stored together under one number and similar
in color and state of preservation. They are almost certainly from one
individual horse and probably are P 3 , Mi, and M 2 , although the pre-
molar might be P 4 . The largest tooth is as large as a molar, but not as
large as a premolar, of Equus simplicidens and is probably a P 3 . The
next-largest tooth is markedly smaller than the P 3 and is probably
Mi. The P 4 , apparently missing, should be intermediate in size be¬
tween these two teeth. The smallest tooth is very small and must be

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

M 2 . In none of these three teeth does the valley between protoconid
and hypoconid penetrate between metaconid and metastylid, although
it approaches the junction in the presumed M 2 . In neither of the two
larger teeth, at least one of which must be a premolar, are the
metaconid-metastylid strongly pillared, as are the premolars of E
simplicidens.

Of the two lower teeth in the Midwestern University collection,
TTU-P 6408 measures 24.1 X 13.9, and the protoconid-hypoconid
valley reaches, but does not enter, the metaconid-metastylid isthmus.
The crown height is about 38. Number TTU-P 6409 measures 24.4
X 13.9; crown height, 35. Again the protoconid-hypoconid valley
approaches, but does not enter between, the metaconid-metastylid
isthmus. Both of these teeth are so small that they must be worn
molars, but in the molars of E. simplicidens , even in specimens as
greatly or more greatly worn, the protoconid-hypoconid valley pene¬
trates deeply between metaconid and metastylid. These two lower
teeth are referred to E. cumminsi.

In the lower part of the diatomite at the Red Quarry, the articulated
proximal and medial phalanges of a horse were discovered, and near¬
by was a partial splint bone. The toe bones are much larger than those
of Nannippus but are smaller than those of Equus simplicidens. Di¬
ameters of the proximal ends of the largest Nannippus (TTU-P 6411),
E. cumminsi (TTU-P 6412), and smallest E. simplicidens (TTU-P
6413) proximal phalanges from the Blanco are, respectively: 21.2 X
23.8; 30.0 X 40.8; 32.1 X 49.5. The length of the Nannippus bone
is 48.8; that of the E. simplicidens, 78.5. The distal end of the E.
cumminsi proximal phalanx (TTU-P 6412) is greatly eroded and
partially missing, but the estimated length is about 85. Measurements
of Nannippus (TTU-P 6413), E. cumminsi , and E. simplicidens
(TTU-P 6414) medial phalanges are: proximal diameter. 18.5 X
23.8; 26.8 X 38.9; 30.0 X 45.7; greatest length, 28.8, 42.6, 48.0.

Also found is an upper third molar from the Marmot Quarry. The
tooth is low crowned (36 high) but not excessively worn. The lakes are
simple, the styles are strong. The protocone is elongated (10.1 long)
and slender, as the protocones of E. simplicidens almost never are.
The tooth is very small (24.0 X 22.6). It, too, is referable to E.
cumminsi.

Equus cumminsi has been referred by several workers to the sub¬
genus Asinus but the only material representing the species consists of
the teeth and toe bones listed in this account and questionably referred
lower jaws from elsewhere than the Blanco. Reference to subgenus
must await better topotypical material.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

35

Order Artiodactyla
Family Tayassuidae

Platygonus bicalcaratus Cope

1893. Platygonus bicalcaratus Cope, 4th Ann. Rept. Geol. Surv. Texas, p. 68 .
Holotype from the Blanco.

1903. Platygonus texanus Gidley, Bull. Amer. Mus. Nat. Hist., 19:476. Holo¬
type from the Blanco.

Referred specimens .—Partial skull, shattered and lacking portions posterior
to orbits but dentition complete except for incisors and right M 3 (TTU-P
6415, CQ); posterior half of right lower jaw with P 4 -M 3 (TTU-P 6416, CQ);
lower jaw fragment with M 2 -M 3 (TTU-P 6417, LQ); right jaw ramus of piglet
with DP 2 -DP 4 and crown of unerupted permanent Mi (TTU-P 6418, CQ);
articulated front leg from radius-ulna to hoofs (TTU-P 6419, CQ); articulated
hind leg from middle of tibia to hoofs, lacking tip of one metatarsal and two
phalanges (TTU-P 6420, CQ); numerous isolated tusks, teeth and post-
cranial elements (TTU-P 6630-6647, 6665, 6669-6692).

This species was described on the basis of a tooth fragment. Gidley
(1903a) Figured two fine palates from the Blanco, referring one of
them to Cope’s species and describing the other as a new species.
Meade (1945) described additional material and showed that some of
the characters considered diagnostic by Gidley were individual vari¬
ants but still thought that there were two species in the Blanco. Hib¬
bard and Riggs (1949) found that the characters thought diagnostic
by Meade were also variable and referred Gidley’s Platygonus texanus
to P. bicalcaratus. The characters of both P. bicalcaratus and P.
texanus, as listed by Gidley and by Meade, are apparent in the present
collection. Some unerupted teeth have very high cusps, whereas
others have relatively low ones. Some have the major cusps quite
close together; in others the cusps are well separated. Some teeth
do show the tapirlike features mentioned by Gidley. Extreme variation
is apparent in all characters mentioned, including the relative develop¬
ment of the heel of M 3 and M3. The large size of the Blanco peccary
tends to accentuate the variation in dental features.

Few writers have emphasized the large size of P. bicalcaratus and
the variation in size of adults. The largest ones are doubtlessly males,
and the largest specimen (jaw fragment, TTU-P 6417) has an M 3 that
measures 33.5 X 17.5, Jaws with the M 3 less than 25 are probably
those of females.

The jaw of an infant pig has the milk dentition almost unworn and
the permanent Mi crown completely developed but not erupted. DP 2 -
DP 4 measures 38.6; DP 2 , 8.7 X 5.4; DP 3 , 11.3 X 6.7; DP 4 ,
19.1 X 10.2.

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

In the gray clay at the Carter Quarry, two incomplete, articulated
peccary legs were found. One was a front leg and one a back. They
were several yards apart but on the same level and might not have
come from the same individual. They are from individuals of similar
size and are probably from females.

The tip of the olecranon is missing from TTU-P 6419, but the
greatest length of the radius-ulna was about 210. The conjoined meta-
carpals measure: greatest length, 95.4; proximal end, 17.2 X 30.0;
midshaft, 12.1 X 23.5; distal end, 17.4 X 33.8. The proximal pha¬
langes measure: greatest lengths, 38.6, 39.6; medial phalanges, 27.7,
29.0; ungual phalanges, 33.3, 35.5.

In the back leg (TTU-P 6420), the proximal half of the tibia, the
tip of the external metatarsal, and external phalanges one and two
are missing. The ungual phalanges are slightly damaged. Selected
measurements are: metatarsal, greatest length, 104.1, proximal end,
24.0 X 27.0, midshaft, 13.7 X 21.9, distal end, ?; greatest length of
calcaneus, 79.9; astragalus, 42.3; proximal phalanx, 40.5; medial
phalanx, 28.4.

Family Camelidae

Remains of four, possibly five, kinds of camels have been found at
the Blanco. Material representing the giant camel, Titanotylopus
spatulus , includes nearly complete skulls, lower jaws, and a skeleton.
A small, slender-limbed camel, Tanupolama blancoensis, is known
from a skeleton (Hibbard and Riggs, 1949), lower jaws, and iso¬
lated elements. The little camel is rare but fossils are distinctive and
easily recognized. A third species of camel is moderately large and
has the advanced dental characters of the Pleistocene genus Camelops.
This taxon is rare and is known definitely only from lower jaws. The
fourth kind of camel, apparently known only from limb elements,
has caused much confusion and speculation. This large, exceedingly
long-limbed camel seems to be confined to the Blanco local fauna.

Meade (1945) first recognized the presence of the long-legged
camel fossils in the Blanco. However, Matthew, in 1924, had found
the skeleton of a small camel with long, slender limbs at the Blanco
and proposed, in manuscript, new generic and specific names for
the specimen. The manuscript was never published, and Meade had
never seen the skeleton. Meade supposed the skeleton to be the large,
long-legged species and used Matthew’s name, Leptotylopus percelsus,
for the large, slender limb bones he had found; but as used by Meade,
the name remains a nomen nudum. Hibbard and Riggs (1949) later
examined the skeleton collected by Matthew and found it to belong to

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

37

the small camel, Tanupolama blancoensis , named by Meade (1945)
in the same paper where he had used the name Leptotylopus percel-
sus. Meade (1945) first discovered the long, slender limb bones of the
larger camel, and recognized their novelty, but through a technical
error left them without a name.

Hibbard and Riggs (1949:855, 857) thought the long, slender limb
bones found by Meade might go with the lower jaws he had referred
to Camelops or to the genus Pliauchenia. Inasmuch as no described
species of either genus has such limbs, this implies that the Blanco
camel is an undescribed taxon.

On the basis of lengths of the limb elements as given by Meade,
Webb (1965) thought that the fossils might be extreme variants of
Titanotylopus. Had Webb seen the specimens, however, he would
not have made this error. The bones are not only longer than most or
all Titanotylopus limb elements, they are far more slender and dif¬
ferent in proportions.

During the present investigations, part of an articulated back leg
of the long-legged camel was found. The tarsal elements and distal end
of the tibia were present but too rotted to recover. The metatarsal
and phalanges, except the ungual phalanges, are fairly well preserved.
This specimen and the limb bones, and perhaps some vertebrae, at
the University of Texas, seem to be the only certain representatives
of the species. No cranial or dental materials have been found in asso¬
ciation with the limb bones. Most type specimens of camel species
are cranial or dental elements. However, it is necessary to have a name
for the large, long-legged came , and unmistakable association of
name and limb elements requires use of a limb bone as the holotype
of the species described below, for which I propose the generic name:

Blancocamelus new genus

Distribution. —Known only from the Blanco Formation, uppermost
Pliocene or earliest Pleistocene, Blancan age, Crosby County, Texas.

Diagnosis. —A large camel with exceedingly long, slender limbs.
Limbs longer than and relatively more slender than the limbs of any
known living or extinct large camel.

Etymology .—Genus named for the Blanco Formation of Crosby
County, Texas.

Type species. —The type and only known species of this genus
is described below:

Blancocamelus meadei new species

Holotype. —Metacarpal (TMM 31179-20).

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Type locality ,—Blanco Formation, Crosby County, Texas. Accord¬
ing to Meade (1945:520), the Leptotylopus [Blancocamelus ) speci¬
mens came from his quarry 9, “650 yards NW of Crawfish ranch
house, on S. side of draw, 17 feet above basal contact, in gray sand
lens immediately above ‘flaggy limestone’ member.” See also
Meade’s {op. cit., 510) map.

Distribution .—Known definitely only from the Blanco Forma¬
tion, uppermost Pliocene or lowermost Pleistocene, Crosby County,
Texas.

Referred specimens .—Metatarsal with articulated phalanges ex¬
cept ungual phalanges (TTU-P 6421, isolated find 100 yards west
of Carter Ouarry); radius-ulna (TMM 31179-28), tibia (TMM 31193-
2), proximal phalanges (TMM 31176-39, 31176-35), medial phalanx
(TMM 31193-2).

Diagnosis. —Limb bones exceedingly long and relatively slender.
Probably the longest-limbed of known extinct or living camels.

Description and comparisons .—The limb bones of Blancocamelus
meadei are very long, in the upper size range or exceeding the maxi¬
mum length of limb bones of species of Titanotylopus, the giant
camels. The limb bones are, however, relatively more slender, rounded
in cross section and less transversely flattened, than the bones of the
giant camel. The two forms are quite unalike in appearance (Fig. 6).

The limb bones of Blancocamelus meadei resemble those of Tanu-
polama blancoensis in proportions. They are, however, much larger.
Measurements of comparable bones of Blancocamelus (Meade, 1945)
and of a large male Tanupolama blancoensis (Hibbard and Riggs,
1949) are: metacarpal, 465 versus 610; tibia-fibula, 530 versus 650;
largest proximal phalanx, 130 versus 142. The proximal phalanx
measuring only 121 (Meade, 1945) probably belongs to Tanupolama.

The metatarsal with articulated phalanges (TTU-P 6421) is a
bit smaller than the bones listed by Meade, and might have belonged
to a female. Its greatest length is about 540, versus 428 in
Tanupolama.

Direct comparison of Blancocamelus to Camelops cf. traviswhitei
is not possible because the latter species is definitely known from the
Blanco only by lower jaws. However, if, as suspected (see account of
C. traviswhitei ), some of the small metapodials referred to Titano¬
tylopus by Meade actually belong to Camelops, Blancocamelus differs
from Camelops cf. traviswhitei in a similar fashion but to a greater
degree than it differs from Titanotylopus.

Etymology. —The species is named for Grayson Meade.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

39

Fig. 6.— Metatarsals and proximal phalanges of camels: Blancocamelus
meadei (TTU-P 6421), right and Titanotylopus spatulus (Cope) (MU 8812),
left. Both are from specimens found in articulation. White rectangle is 5 centi¬
meters long.

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

Remarks .—For measurements of type and referred specimens at
the University of Texas, see Meade (1945:538). These specimens were
reexamined and I agree with Meade that all belong to the same
species. Skinner et al. (1972) mentioned some elongated camel verte¬
brae in the University of Texas collection that they thought might
belong to the long-legged camel. Akersten (1972) referred a fragment
of a radius-ulna to the long-legged camel and concluded that the taxon
was without a name.

Camelops cf. traviswhitei Mooser and Dalquest

1945. Camelops cf. kansanus, Meade, Univ. Texas Publ.. 4401:537.

1975. Camelops traviswhitei Mooser and Dalquest, Southwestern Nat., 19:

341-345. Holotype from Aguascalientes, Mexico.

Referred specimens .—Right and left lower jaws with symphysis and roots of
canines, cheek teeth of both sides (TMM 31181-212); five lower jaw rami
(TMM 31181-134, 14, 8, 142, 175); lower jaw fragment with P 4 -M 2 (TTU-P
6422).

Meade (1945) correctly suspected that the Camelops specimens
from the Blanco might belong to a species undescribed at the time he
was working. Mooser and Dalquest (1975) described a new species
of Camelops from Aguascalientes, in central Mexico, on the basis of
skulls and lower jaws and tentatively referred limb bones. The Blanco
lower jaws resemble the Mexican camel in having sharply V-shaped
lakes, without cementum, in the lower cheek teeth, and having the
enamel of the lakes very thin on the labial side and thick on the
lingual side. Other kinds of Camelops have the lakes of the cheek
teeth of bent-oval shape, blunt at the ends, and outlined evenly with
thick enamel. Because only lower jaws from the Blanco and
Aguascalientes can be compared, and because lower dentitions of
Camelops are so variable in size of teeth, positive reference of the
Blanco Camelops must be deferred. It is possible that better material
might show the Blanco Camelops to be a species distinct from C.
traviswhitei. Some postcranial material at the University of Texas
was referred by Meade to Camelops. The material is certainly of
normal Camelops appearance. It might be mentioned also that some
of the smallest metapodials in the University of Texas collection,
some labeled “ Gigantocamelus ,” are small enough to belong to
Camelops.

Hibbard and Riggs (1949) named Pliauchenia cochrani from the
Rexroad Formation of Kansas. These authors noted the Camelops-
like features of the dentition and figured a referred phalanx and
broken metatarsal of Camelops- like proportions. The lakes of the

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

41

teeth of this species are like those of typical Pleistocene Cametops,
cement-filled and blunt-ended. The characters of the species are sur¬
prisingly like those of Camelops mexicanus (del Castillo), from the
late Pleistocene of the Valley of Mexico. This form also has a small
Pi, a small P 3 (both teeth missing in typical Camelops), and the lakes
of the cheek teeth are bent-oval in shape and filled with cementum.

Webb (1965) considered Pliauchenia cochrani to be somewhat
intermediate between the genera Megatylopus and Camelops , and
referred the species to the genus Megatylopus because the lower P 3 is
present. This is a reasonable treatment, but it should be noted that the
Hemphillian Megatylopus matthewi Webb, the Blanco Camelops, and
the Mexican C. traviswhitei have in common lakes of the cheek teeth
that lack cementum, are sharply “V” shaped, and have thick enamel
on the lingual sides but thin enamel on the labial sides. On the other
hand, Megatylopus cochrani and typical Pleistocene Camelops, as
well as Camelops mexicanus, have cementum-filled, bent-oval lakes
with uniformly thick enamel borders.

Hibbard and Riggs (1949:855) suggested that the limb bones from
the Blanco, here described as Blancocamelus meadei , belonged with
the lower jaws Meade referred to Camelops. Inasmuch as Blanco¬
camelus is known by four limb bones (disregarding phalanges), and
Camelops is known from lower jaws, it is tempting to think that the
fossils might all pertain to one species. However, as Meade noted
(1945:537), there is a quanitity of typical Camelops postcranial ma¬
terial in the University of Texas collection, all of which is very dif¬
ferent from the slender, elongated bones of Blancocamelus. Ap¬
parently this material was not found in actual association with the
Camelops jaws, but no specimens of Camelops seem to have been
taken at the quarry where the Blancocamelus bones were found
(Meade, 1945:520). If the Camelops cf. traviswhitei jaws belong to
Blancocamelus, the Camelops-Yike postcranial material is unassigned.
Furthermore, the jaws of Camelops from the Blanco seem too small to
belong to the same kind of camel as do the limb bones of Blanco¬
camelus. Jaw TMM 31181-175 is complete from incisor bases to the
angle, and TMM 31181-212 has much of the symphysis. These jaws
are of normal Camelops proportions and are not elongated. To judge
from the limb bones, Blancocamelus probably had larger jaws.

Titanotylopus spatulus (Cope)

1893. Pliauchenia spatula Cope, 4ih Ann. Rept. Geol. Surv. Texas, p. 70.

Holotype from the Blanco.

1945. Gigantocamelus spatula , Meade, Univ. Texas Publ., 4401:531.

1965. Titanotylopus spatulus , Webb, Bull. Los Angeles Co. Mus., 1:35.

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

Referred specimens .—Most of skeleton with fragmentary skull, almost com¬
plete lower jaws, most of limbs, and parts of the axial skeleton (MU 8812, CQ):
nearly complete skull (MU 9225, MQ); isolated jaw fragments, teeth, and post-
cranial elements, in Midwestern University collection. Many almost complete
to fragmentary skulls, lower jaws, and postcranial elements in the University
of Texas collection (see Meade, 1945, for list and measurements).

The skull, dentition and some of the limb bones of the giant camel
have been well figured and described by Meade (1945) and Hibbard
and Riggs (1949). The males of this species are larger than the fe¬
males, have larger and especially stouter canines, and have a lower
first premolar, which is lacking in females. The skeleton in the Mid¬
western University collection is apparently a male and the nearly com¬
plete skull is also a male.

Webb (1965) considered Gigantocamelus Barbour and Schultz
to be congeneric with Titanotylopus Barbour and Schultz, but Skinner
et al. (1972) retain Gigantocamelus as a valid genus. They suggest a
possibility that Titanotylopus might pertain to the long-legged camel
herein named Blancocarnelus. The type species of Titanotylopus is T.
nebraskensis, based on fossils from Nebraska, but 1 am aware of no
material from Nebraska like the limb bones of Blancocarnelus. Hib¬
bard and Riggs (1949) listed an elongated camel thoracic vertebra
from the Rexroad Formation of Kansas, and Skinner et al. (1972)
suggested that it might pertain to the camel here named Blanco-
camelus. I have not seen the specimen, but one thoracic vertebra as¬
sociated with the Titanotylopus skeleton from the Blanco has a very
long neural spine, like the specimen from Kansas. The identity of the
Kansas vertebra must remain in doubt, but Blancocarnelus is to date
known with certainty only from the Blanco.

Cope’s (1893) holotype of Pliauchenia [Titanotylopus] spatulus
is a lower jaw and was well figured. There can be no doubt as to the
identity of Cope’s holotype and of the lower jaw belonging to the
present skeleton. The skeleton has the large, stout, transversely flat¬
tened metapodials that are usually associated with this giant camel.
Webb’s (1965) suggestion that the holotype of Titanotylopus nebras¬
kensis is a female of another species of the same genus of giant camel
seems reasonable.

The isolated skull (MU 9225) and the skeleton (MU 8812) are un¬
usually complete and will be described in detail elsewhere. The col¬
lection includes two fragmentary lower jaws with the milk dentition
and a few deciduous teeth.

Tanupolama blancoensis Meade

1945. Tanupolama blancoensis Meade, Univ. Texas Publ., 4401:535. Holotype
from the Blanco.

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

43

Referred specimens .—Holotype lower jaw (TMM 31181-126), two lower
jaw fragments with dentitions (TMM 31176-25, 31182-42), maxillary fragment
(TMM 31176-5), and a few isolated teeth and foot bones in the Texas Tech
University collection.

The little camels of the genus Tanupolama remain poorly under¬
stood although Lundelius (1972) has recently given a fine account
of the Late Pleistocene T. mirifica from Florida and the Texas coast.
In some Pleistocene local faunas, as the Gilliland local fauna of Knox
County, Texas (Hibbard and Dalquest, 1962) and the Cedazo local
fauna of Aguascalientes, central Mexico (Mooser and Dalquest, in
preparation), two species of Tanupolama occurred sympatrically. The
specimens from the Blanco indicate that T. blancoensis was a rela¬
tively large, stilt-legged species. A few postcranial elements are rela¬
tively small. These might have belonged to females, but the amount of
sexual dimorphism in this genus is unknown.

Camel id, undetermined

Among the proximal phalanges of camels in the Midwestern Uni¬
versity collection is a specimen that cannot be referred to any genus
or species (TTU-P 6423, Fig. 7). The specimen is an isolated find,
from the Marmot Quarry. Measurements are: greatest length, 106.8;
proximal end, 36.0 X 50.3; midshaft, 23.2 X 28.8; distal end,
27.6 X 42.2. The phalanx is so broad and flat that, at first glance, it
seems to belong to a horse. However, the articular surfaces show
that it is definitely of a camel. It is too stout to be Tanupolama , al¬
though it is slightly shorter than phalanges of that genus from the
Blanco. It differs from both Tanupolama and Blancocamelus in being
almost flat on the posterodorsal surface, rather than having an ele¬
vated dorsal shoulder. From Titanotylopus it differs in being much
flatter dorsoventrally, with both articular surfaces less laterally ex¬
panded. It is of a mature animal and there is no indication of fracture
or other abnormality. It differs so radically from other camel pha¬
langes from the Blanco that it may well represent a taxon other than
the four known genera. Alternatively, it might be the proximal pha¬
lanx of Camelops cf. traviswhitei.

Family Antilocapridae
Antilocaprid, undetermined

Referred specimens .—Lower jaw fragment with Mi-M 2 (TTU-P 6424, RQ),
lower jaw fragment with DP 3 -Mi (TTU-P 6425, RQ), lower jaw fragment with
DP 2 -Mi (TTU-P 6664, RQ), calcaneus (TTU P 6427, MQ), median phalanx
(TTU-P 6428. RQ), ungual phalanx (TTU-P 6429, CQ), proximal end of proxi¬
mal phalanx (TTU-P 6426, CQ), cuboid (TTU-P 6430, CQ).

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Fig. 7.—Proximal phalanges of camels from the Blanco: left to right, unde¬
termined camelid (TTU-P 6423); Titanotylopus .spatulus (MU 8812); Blanco-
camelus meadei (TTU-P 6421); Tanupolama blancoensis (MU 7119). White
rectangle is 5 centimeters long.

Antilocaprid remains are usually uncommon but widely distributed
in early Blancan local faunas of the western United States. So far as
I am aware, most of the material is not specifically identifiable.
Meade (1945) referred a jaw fragment and part of a tooth from the
Blanco to Capromeryx. I have seen this material and think it and
the specimens listed above are not Capromeryx but a very different
kind of antilocaprid.

Only jaw fragments, teeth, and foot bones are available from the
Blanco, but these are distinctly larger than are those of Capromeryx
fossils from the Slaton Quarry of Texas or the Rancho La Brea of
California. The bones and teeth represent a species about 25 per cent
smaller than the living species of Antilocapra, and both teeth and
foot bones are thinner and more transversely compressed than are
corresponding elements of all antilocaprid genera with which they
were compared. Identity of the Blanco antilocaprid must await dis¬
covery of the horn core, for most antilocaprid genera and species are
based on the characters of horn cores.

Family Cervidae

Odocoileus cf. brachyodontus Oelrich

1953. Odocoileus brachyodontus Oelrich, J. Mamm., 34:376. Holotype from
the Rexroad Formation of Meade County, Kansas.

Referred specimen. —Fragment of antler (TTU-P 6431, MQ).

DALQUEST— BLANCO LOCAL FAUNA, TEXAS

45

The fragment is only about 35 millimeters long, and averages
about 12 in diameter. It is slightly eroded, but one end has remains
of what seem to be the characteristic, roughened surface of the burr of
a normally shed antler. The fragment is nearly straight. The antler
fragment must have come from a yearling male and probably was shed
in the early spring of the year. The antler fragment can be matched
in size and straightness by spike bucks of Odocoileus virginianus from
the Edwards Plateau of Texas, where the deer are greatly dwarfed.
If the fragment is from the base of a normally shed antler, the deer
probably weighed less than 50 pounds.

Paleoecology

Meade (1945) thought the Blanco local fauna accumulated in a
large lake, the fossils being bones of animals bogged down in mud or
killed by carnivores. The diatomite beds represent one locality
where there was a lake or pond, but the absence of any aquatic verte¬
brates here suggests that the pond was seasonal, like many of the lakes
on the High Plains today. A few aquatic snail shells do occur in the
sandy mud beneath the diatomite, along with abundant fossils of reeds
and aquatic plants. However the lake was of restricted area as shown
by the extent of the lacustrine deposits, and at most probably covered
about 10 acres. No aquatic vertebrate remains were found in the
lacustrine sediments. No microtine rodent remains were present there,
though the marsh would be normal habitat for such mammals. The
only aquatic vertebrate fossil found anywhere in the Blanco is a single
tooth of a large alligator, taken in the Low Quarry. Land tortoises are
not uncommon in the fauna, but pond turtles are absent. No fishes,
amphibians, beavers or otters were found.

Rodents are usually the best indicators of ecological conditions,
and the Blanco rodents indicate semi-arid grassland habitat. The
commonest form is the cotton rat, a grassland species. Common also
are pocket mice and ground squirrels, which are primarily prairie
and desert animals. The pocket gopher is fossorial but avoids brush
or woodland habitat. The kangaroo rat and small cricetines,
though less common, are also prairie mammals. Only the woodrat in¬
dicates denser cover or rocky talus, and woodrats are represented by
only a single tooth.

Most of the herbivores, and all of the common ones, probably
were grazers, including the glyptodon, mastodons, camels, antilocap-
rid and horses. Some browsers are represented, including ground
sloths and deer. The peccary probably required some brush or wood¬
land cover. Such heavier cover may have grown along streams and

46

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ponds, and in shaded valleys. The abundant fossil hackberry seeds at
the Red Quarry prove the abundance of this tree near water, and if
the hackberry was present, the cottonwood almost certainly was
present too.

The evidence suggests that the Blanco local fauna represents one
rather uniform habitat: grassy plains with narrow belts of trees fring¬
ing watercourses and in the shaded parts of valleys. Conditions
were almost identical to those of the High Plains and Texas Pan¬
handle today where not modified by agriculture.

Age of the Fauna

The age of the Blanco has been the subject of much discussion.
Cope (1893:46) recognized that the Blanco local fauna was inter¬
mediate between late Tertiary and Pleistocene faunas and termed it
“more nearly and strictly Pliocene.” Osborn (1903), in his description
of Glyptotherium texanum, stated that the holotype came from the
lower Pleistocene, and was surely aware that the specimen was
from the Blanco. Gidley (1903/>:624) definitely stated that the Blanco
was Pliocene. Thereafter the Pliocene age of the Blanco was accepted
until Evans and Meade (1945) and Meade (1945) maintained that the
Blanco was early, perhaps earliest, Pleistocene.

In his arguments, Meade (1945:516-519) tried to show that not
merely the Blanco local fauna, but Blancan faunas in general, were
of early Pleistocene age. Later authors have generally accepted a
Blancan Age extending from the late Pliocene through the early
Pleistocene, and typified by a characteristic fauna with index mam¬
malian genera and species. They have usually accepted Meade’s thesis
as applying to an early Pleistocene age for the Blanco local fauna,
but not, as he intended, for all Blancan faunas. Yet, the available
faunal list for the Blanco local fauna indicated closer correlation with
the accepted Blancan Pliocene local faunas than with Blancan Pleisto¬
cene faunas.

The absence of microtine rodents and aquatic mammals from the
Blanco makes correlation with other Blancan local faunas difficult,
for most known Blancan local faunas are from more nothern areas,
where microtines are abundant and beavers and otter are present. The
best-known Blancan Pliocene local fauna is the Rexroad local fauna
of Meade County, Kansas.

The Rexroad local fauna is known from several collecting
sites. The largest number of species is known from Rexroad locality
3. However, some species known from the Rexroad local fauna
have not been recorded at locality 3 (for example, Reithrodontomys

DALQUEST—BLANCO LOCAL FAUNA, TEXAS

47

rexroadensis , Titanotylopus spatulus), The list of Rexroad mammals
in the following correlation chart is primarily from Skinner et ai
(1972) with regard to Rexroad locality 3 mammals, with additions
of published species records from other Rexroad localities.

Of the 45 kinds of mammals identified in the Blanco local fauna,
32 have equivalents (same or similar species) in the Rexroad. There
are, of course, many species known from the Rexroad that have not
been found in the Blanco. Twenty-eight identified genera are common
to both local faunas. Fourteen species are the same in both faunas,
and four others are perhaps referable to the same species. In many
instances, species identified in one local fauna have their equivalents
in the other local fauna identified only to genus. Better material will
doubtless show that some, perhaps most, of these are also identical.

On the other hand, Hesperoscalops and Stegomastodon are repre¬
sented in each fauna by different species. More material may show
that there are still other distinctions between the two local faunas
that are not the result of geographic distance or ecological dif¬
ferences in the two localities.

The similarity of the two local faunas is apparent. The Blancan was
a long time interval, perhaps as long as three million years (Bjork,
1970) and Blancan local faunas are difficult to place in sequence.
Examination of the comparison table of Skinner et ai (1972) shows
no other Blancan local fauna to resemble the Blanco local fauna as
closely as does the Rexroad. The Blanco has no markedly advanced
elements, and the mole and pocket gopher are comparatively primitive.

Faunal comparison suggests that the Blanco is of about the same
age as the Rexroad, at most only slightly younger.

The Guaje volcanic ash bed exposed in the roadcut just north of
Mount Blanco (Izett et ai , 1972) has been dated at 1.4 million years
bp. This ash bed, however, lies nearly at the surface of the ground
and is separated by 30 or more feet of weathered caliche rubble from
the uppermost rocks that might be part of the Blanco Formation. The
vertebrate fossils come from much deeper in the sediments.

Volcanic ash settles in water-filled depressions in the existing land
surface. Its age is not that of the underlying rocks; it might be slight¬
ly or greatly younger. It does furnish a minimum date for underlying
sediments. At the Blanco the ash may have settled in a deflation basin
in the surficial, post-Blancan deposits. It indicates only that the
Blanco local fauna is more than 1.4 million years old.

Whether the Blanco is Pliocene or Pleistocene in age will depend on
the concept of the extent in time of the Pleistocene, In any event, the
Blanco local fauna is either latest Pliocene or earliest Pleistocene in
age.

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OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY

Table I. —Comparison of the Blanco local fauna with the Rexroad local fauna

of Kansas.

Blanco local fauna

Rexroad local fauna equivalent

Order Insectivora

Sorex taylori

Sorex taylori

Hesperoscalops hlancoensis

Hesperoscalops rexroadi

Order Chiroptera

bat, near Tadarida

Order Edentata

Glyptotherium texanum
Megalonyx leptostomus

Megalonyx sp.

Glossotherium near chapadmalense Glossotherium sp.

Order Lagomorpha

Hypolagus sp.

Hypolagus re gal is

Nekrolagus cf. progressus

Nekrolagus progressus

Order Rodentia

Paenemarmota harbouri

Paenemarmota harbouri

Spermophilus sp. large
Spermophilus sp. medium
Spermophilus ef. howelli

Spermophilus howelli

Geontys sp.

Geomys (Nertogeomys) minor

Perognathus cf. rexroadensis

Perognathus rexroadensis

Perognathus cf. pearlettensis

Perognathus pearlettensis

Prodipodomys centralis

Prodipodomys centralis

Onychotnys sp.

Onychomys gidleyi

Reithrodontomys sp.

Reithrodontomys rexroadensis

Bensonomys sp.

Bensonomys eliasi

Baiomys sp.

Baiomys rexroadi

Peromyscus near kansasensis

Peromyscus kansasensis

Neotoma cf. quadriplicaius

Neotoma quadriplicatus

Sigmodon medius

Sigmodon medius

Order Carnivora

Can is lepophagus

Can is lepophagus

Borophagus diversidens
Canimartes cumminsi

Borophagus sp.

Spilogale rex road i
? Chasmaporthetes johnston i

Spilogale rexroadi

Felis cf. lac ustr is

Felis lacustris

Pan thera (Dinofelis) palaeoonca

? Homotherium

Homotheriini, undetermined

Order Proboscidea

Rhy nchotherium praecursor

Stegotnastodon mirificus

Stegomastodon rexroadensis

Mastodon, undetermined

Order Perissodactyla

Nannippus phlegon

Nannippus phlegon

Equus simplicidens

Equus cumminsi

Equus simplicidens

DALQUEST—BLANCO LOCAL FAUNA, TEXAS 49

Table I.— Continued.

Order Artiodactyla

Platygonus bicalcaratus

Titanotylopus spat ulus
Tanupolama blancoensis

Odocoileus brachyodontus

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Address of author: Department of Biology. Midwestern University, Wichita
Falls , Texas 76308. Received 23 April, accepted 21 August 1974.