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MUS. COMP, ZOOL
L./BRARY

Ser & 1964

RFARVARD
UNIVERSITY,

BA

Prasopy Museum or Narura.L History

YALE UNIVERSITY

Number 83 July 15, 1964 New Haven Conn.

PSEUDODONTORNIS AND OTHER LARGE MARINE
BIRDS FROM THE MIOCENE OF SOUTH CAROLINA

James A. Hopson

Preasopy Mvusrtum or Natrurat Hisrory, Yate Universiry

INTRODUCTION

While engaged in the reorganization’ of the vertebrate fossil
collections at the Peabody Museum of Natural History, Yale
University, the writer discovered the incomplete lower jaw of
a large bird from the Miocene phosphate deposits near Charles-
ton, South Carolina. The specimen is clearly referable to the
family Pseudodontornithidae, an extinct group of very large
oceanic birds characterized by the presence of vertical bony
tooth-like processes, or, as the family name implies, pseudo-
teeth, on the margins of their jaws. This is the first record
of a pseudotoothed bird from eastern North America.

The only previously described bird from these deposits is
Palaeochenoides mioceanus (Schufeldt, 1916) represented by
a partial femur. A further search made in the collection of
phosphate beds fossils at Yale for additional avian material
yielded negative results. Professor Bryan Patterson called my

‘Research reorganization of this collection was supported by National
Science Foundation grant GB-247 (1962).

2 Postilla Yale Peabody Museum No. 83

attention to a large undescribed tarsometatarsus from the
phosphate beds which is in the Museum of Comparative Zool-
ogy at Harvard. Dr. Pierce Brodkorb later informed me of a
second undescribed tarsometatarsus from the Cooper River
near Charleston; this specimen is in the collections of the
United States National Museum.

These two specimens and the recently discovered dentary
are described in this paper. The possibility that the two tar-
sometatarsi and the femur described as Palaeochenoides might
belong to members of the family Pseudodontornithidae is
assessed.

ACKNOWLEDGMENTS

Thanks are due Professor Bryan Patterson for bringing to
my attention the existence of the tarsometatarsus in the Mu-
seum of Comparative Zoology and to Dr. Ernst Mayr for
permission to borrow and describe it.

Dr. Alexander Wetmore of the United States National
Museum very generously allowed me to borrow and describe
the tarsometatarsus from that institution. Dr. Wetmore’s kind-
ness in turning over to me his notes on this specimen, to
which he had already devoted considerable study, is also grate-
fully acknowledged.

Dr. Hildegarde Howard supplied me with a mold of the
foot of Osteodontornis orri. Dr. Howard and Dr. Pierce Brod-
korb provided information on fossil and recent birds not avail-
able in the literature and offered useful criticism of the manu-
script. Dr. John H. Ostrom and Dr. Elwyn L. Simons also

gave welcome advice and criticism.

ABBREVIATIONS

MCZ—-Museum of Comparative Zoology, Harvard University,
Cambridge.

USNM—United States National Museum, Washington.

YPM—Peabody Museum of Natural History, Yale University,
New Haven.

ks | EO PTVPArs ft

Ser ds 1964

July 15, 1964 Miocene Birds from South" @arolina O 3
UNIVERSITY.

PREVIOUS KNOWLEDGE OF PSEUDOTOOTHED BIRDS

The only previously described pseudotoothed bird of definite
North American provenance is Osteodontornis orri from the
Upper Miocene of California (Howard, 1957). The type speci-
men of this species consists of a crushed skull and lower jaws,
relatively complete though crushed wing and leg bones, several
caudal vertebrae, and the impressions of a number of wing
feathers. It is by far the most complete pseudotoothed bird
specimen known, but its damaged state makes many areas of its
anatomy extremely difficult to interpret. Howard estimates the
wingspread of the living bird to have been over 16 feet. A
second specimen of QO. orri from California, consisting of frag-
mentary upper and lower jaws and a partial, though uncrushed,
atlas, was later described by Howard and White (1962).

A closely related form, Pseudodontornis longirostris, had
earlier been described by Spulski (1910) and redescribed by
Lambrecht (1930). This form is known from a skull and right
lower jaw which had been purchased in 1905 by the Zoological
Institute of Koénigsberg, Germany, from a Brazilian sailor.
No locality or age data were ever obtained for this specimen ;
it is possibly from Brazil, but this is far from certain. In size,
the type skull is only slightly larger than that of Osteodon-
tornis orre.

A third, more distantly related, “toothed” bird, about half
the size of the above forms, has long been known from the
Eocene London Clay. This is Odontopteryx toliapica, described
by Sir Richard Owen in 1873 from an incomplete skull and jaws.
It is currently placed in the monotypic family Odontopterygidae.
The most obvious distinguishing feature between Odontopteryx
and the pseudodontorns is that the “teeth” in the former slant
forward, while those in the latter stand perpendicular to the
margin of the jaw. The three genera are usually grouped as the
suborder Odontopterygia of the Order Pelecaniformes (Brod-
korb, 1963), though Howard (1957) believes they merit sep-
arate ordinal rank.

AGE OF THE PHOSPHATE BEDS BIRDS

In the nineteenth century, abundant vertebrate fossils were
dredged from the beds of coastal rivers in the vicinity of Charles-

4 Postilla Yale Peabody Museum No. 83

ton, South Carolina, during the course of commercial phos-
phate digging. The phosphate deposits have long been recog-
nized to contain a mixture of fossils ranging from Miocene to
Pleistocene ages. The remains of land mammals are almost
wholly from the Pleistocene, though a few are clearly of Pliocene
and even Miocene ages (Allen, 1926; Simpson, 1932). The
marine fossils

cetaceans, sirenians, bony fishes, and sharks—
seem to be mainly Miocene in aspect, though mixing here too
cannot be ruled out. One sirenian, Halitheriwm alleni, is referred
to a genus which is not known above the Lower Miocene in
Europe (Simpson, 1932).

That part of the phosphate deposits which is of Miocene age
is now considered to be a northern extension of the Hawthorne
Formation cf Florida (Wilmarth, 1938). Brodkorb (1968a)
summarizes the evidence for considering the Hawthorne For-
mation to be of late Early Miocene age. The phosphate beds
marine fauna is not known to cast doubt on this age determina-
tion. The birds described here are almost certainly part of
this fauna and, therefore, may be considered at least tentatively
to be of late Early Miocene age.

DESCRIPTION AND DISCUSSION OF MATERIAL
Famity PSEUDODONTORNITHIDAE Lamprecur

Pseudodontornis longirostris (Spulski)
Figure 1A

~

Odontopteryx longirostris Spulski, 1910, p. 507.

Pseudodontornis longirostris, Lambrecht, 1930, p. 1.

This specimen (YPM 4617) consists of a portion of the
anterior half of a right dentary bearing three prominent
teeth? and the remnants of several smaller ones. It is from
the large C. A. Scanlon collection cf phosphate beds fossils
which was acquired by Yale Peabody Museum in 1913. No
locality data on the Scanlon collection exists in Peabody

* Although these tooth-like processes are not true teeth, the quotation marks
will be omitted in the rest of the discussion.

July 15, 1964 Miocene Birds from South Carolina 5

Museum records other than the very general: “Phosphate dig-
gings about Charleston, S8.C.” However, Shufeldt (1916, p.
344), with reference to the type locality of Palaeochenoides,
quotes a letter from Dr. Earle Sloan of Charleston which states,
“The Seanlon collection was in the main taken from the rock
dredged from the bed of the Stono River near its source.”

Figure 1. Lateral views of right dentaries of Pseudodontornis longirostris.
A. YPM 4617. B. Type, from Lambrecht, 1930. Both x 1.

Howard (1957) cites as distinguishing features between the
dentaries of the two larger genera of pseudotoothed birds the
following characteristics: in Osteodontornis there are “two or
threc smaller ‘teeth’ between each large one on [the] lower
jaw”; in Pseudodontornis there is “only one smaller ‘tooth’
between large ones on [the] lower jaw.” In number and
arrangement of teeth, the Hawthorne dentary corresponds
more closely to Howard’s characterization of O. orri, but I
believe the “dental” distinctions which she cites are not valid.

6 Postilla Yale Peabody Museum No. 83

Neither Spulsky (1910) nor Lambrecht (1930) made any
reference to more than a single tooth between the large teeth
in the type of P. longirostris, but Lambrecht’s photograph of
the type dentary (PI. II, Fig. 2), which is redrawn in Fig. 1B,
shows a very low rounded protuberance midway between the first
and second teeth and another between the third and fourth teeth.
These protuberances are identical in appearance to the broken
bases of similarly placed small teeth in the Hawthorne speci-
men and presumably represent the remnants of formerly com-
plete tooth-like projections. It seems likely that in a well-
preserved jaw of Pseudodontornis the number and distribution
of teeth would probably be very similar to that which Howard
(1957) believes to be diagnostic of Osteodontornis. Therefore,
in identifying the Hawthorne jaw I have utilized as diagnostic
characters only the gross size of the specimen and the sizes of
and distances between the preserved teeth.

The anterior tip of the dentary is unfortunately not pre-
served in either described specimen of O. orri. Howard’s meas-
urements on the more posterior portions of the type mandibles
show that: (1) large teeth are spaced 30-40 mm apart; (2)
large teeth range from 7.5 to 13 mm in height and 7.5 to 10 mm
in basal length; and (3) the largest tooth is the third from
the back (Howard, 1957, p. 12). The measurements of the
Hawthorne jaw are given in Table 1. The two large teeth are
comparable in size to the largest tooth in O. orri but are about
5 mm higher and longer than the smallest tooth of the large
size class. The distance between the two large teeth in the Haw-
thorne jaw is almost 12 mm greater than the maximum distance
in O. orri.

Examinaticn of Lambrecht’s figure (1930, Pl. II, Fig. 2) as
redrawn in Fig. 1B, indicates that the teeth of P. longirostris
are, on the average, larger than those of O. orri. Also, the dis-
tance between the teeth is greater (by about 10 mm), though
Howard (1957, p. 12) states that the distance is about the
same in the two species. A comparison of the Hawthorne jaw
(Fig. 1A) and the comparable region of the type dentary of
P. longirostris (Fig. 1B) indicates that they are remarkably
similar, especially in the distances between the preserved teeth.
On this basis, YPM 4617 is referred to this genus and species.

July 15, 1964 Miocene Birds from South Carolina u

TaABLe 1

MEASUREMENTS ON yea 4617 IN MM

Preserved Length 68.1
Maximum Depth 20.4
Width:

Below Anterior “Tooth” 9.0

Below Posterior “Tooth” 10.1
Distance Between Two Largest “Teeth” 51.9
Distance Between Middle and Posterior “Teeth” 24.5
Anterior “Tooth”:

Height 12.5

Length at Base 12.0
Posterior “Tooth”:

Height 12.2

Length at Base 12.8
Middle “Tooth”:

Height 5A

Length at Base 6.8

‘

The discovery of Pseudodontornis longirostris in the Haw-
thorne Formation of South Carolina establishes a Miocene age
for this species and strengthens the supposition that the type
specimen came from the Western Hemisphere. It does not, how-
ever, demonstrate that the type was necessarily from North
America, for a large oceanic bird of this sort was probably
widely distributed.

The fragmentary Hawthorne specimen is undoubtedly from
near the anterior end of the jaw for it is dorsoventrally very
shallow. Low on its lateral surface is a shallow longitudinal
sulcus which is characteristic of the three known species of
“toothed” birds. In cross section the outer surface of the jaw
is straight and vertical, the inner surface smoothly convex.
The three largest teeth have straight sides which are continuous
with the sides of the jaw. They are inclined somewhat laterally
so that their tips are directly above the outer margin of the
jaw. The bases of the smaller teeth are restricted to the lateral!
half of the jaw margin.

The preserved “dentition” consists of two large teeth 51.9
mm apart and a single smaller tooth about midway between

8 Postilla Yale Peabody Museum No. 83

them (actually 24.5 mm from the posterior large tooth). Half-
way between the middle tooth and each of the larger teeth are
the broken bases of two even smaller teeth. Finally, in each of
the spaces between these five teeth are shiny oval patches, flush
with the jaw margin, which are the bases of four very tiny
teeth of which no remnant is preserved. These teeth correspond
to the “narrow spinelike ridges” in the lower jaw of the second
specimen of Osteodontornis (Howard and White, 1962).

The outer surfaces of the teeth bear longitudinal striations
and small foramina. The foramina undoubtedly represent Volk-
man canals, seen in the thin sections of a tooth of O. orri
(Howard, 1957, p. 10, fig. 5).

A transverse break at midheight across the anterior large
tooth shows that this structure is hollow, with walls about 1.0
mm in thickness. Several thin bony trabeculae extend into the
central cavity from the walls and the break cuts across one
trabecula in the center of the cavity. This conflicts with the
findings of Lambrecht (19830) who states that X rays showed
that the teeth in the type of P. longirostris are not hollow but
are composed of spongy bone. The teeth of O. orri are hollow
and much like the one described here (Howard, 1957), and in
Odontopteryx certain teeth are described as being hollow
(Owen, 1873). Inasmuch as Lambrecht did not examine sec-
tions across the teeth of Psewdodontornis, his statement that
the teeth in this form are not hollow requires further confirma-
tion before it can be accepted.

Famity CYPHORNITHIDAE? Wernmore

?Palaeochenoides mioceanus Shufeldt

Figure 2

This well-preserved distal portion of a left tarsometatarsus
(MCZ 2514) is from the William Pringle Frost collecticn of
phosphate beds fossils which is now in the Museum of Compara-
tive Zoology at Harvard. A number cf fossil mammals from
the Frost collection were described by Allen (1926). He states
that this collection is from the Ashley River. The marine forms,
including the present specimen, are almost certainly from the
Hawthorne Formation.

July 15, 1964 Mhiocene Birds from South Carolina 9

With the exception of the above-described specimen of Pseu-
dodontornis, the only bird previously known from the Haw-
therne Formation of South Carolina is Palaeochenoides mio-
ceanus, described by Schufeldt (1916) from the distal end of
a right femur. Shufeldt believed the affinities of this species to
be with the anseriforms, but Wetmore (1917) subsequently
pointed out that the type femur is distinctly pelecaniform in
morphology. This element indicates that Palaeochenoides was
a very large bird, being, according to Wetmore, somewhat
larger than the living Pelecanus onocrotalus or P. erythrorhyn-
chus. Wetmore (1928) later allied Palaeochenoides with Cy-
phornis, a gigantic Lower Miocene bird, known only from the
proximal end of a tarsometatarsus from Vancouver Island, in
the family Cyphornithidae.

The dimensions of the MCZ tarsometatarsus are commensu-
rate with the expected dimensions of this bone in a bird with a
femur the size of the type specimen of Palaeochenoides mio-
ceanus and with limb proportions approximating those of
Pelecanus or Diomedea. Both.fossil limb bones have very thin-
walled shafts indicating that they were highly pneumatic. With
the exception of the pseudodontorns, with which they cannot
be compared in any detail because of the lack of comparable
well-preserved parts, no other volant bird of this size is known
from the Miocene of North America (Cyphornis is much
larger). Therefore, it is extremely likely that the MCZ speci-
men is referable to Palaeochenoides mioceanus. Were it to show
distinctly pelecaniform features, this assignment would be a
virtual certainty; as it does not, I have qualified its reference
to this species with a question mark. Further discussion of its
relationships is left until the end of this paper.

The shaft cf the tarsometatarsus is broadly oval in cross
section, and is almost completely smooth except for a promi-
nent, though damaged, longitudinal ridge on the anterior sur-
face. This ridge terminates ventrally 17.5 mm above the inner
edge of the middle trochlea. At its lower border, the shaft 1s
22.3 mm wide. The possible function of this structure is dis-
cussed below in connection with the second tarsometatarsus.

In anterior view the shaft is moderately expanded distally ;
in profile its sides are only slightly concave above the trochleae.

10 Postilla Yale Peabody Museum No. 883

Figure 2. ?Palacochenoides mioceanus MCZ 2514, left tarsometatarsus.
A. Acrotarsial view. B. Plantar view. C. Medial view. D. Lateral
view. E. Distal view. X 1.

July 15, 1964 Mhiocene Birds from South Carolina 11

The width through the trochleae is 34.7 mm. The middle
trochlea is the longest of the three. It is relatively broad; the
rims of the articular facets are relatively low with a broad
shallow sulcus between them. The outer trochlea is 4 mm shorter
than the middle one. Its inner rim extends well below its outer.
Viewed laterally, its plantar wing extends slightly beyond, and
its acrotarsial edge slightly below, the corresponding edges of
the middle trochlea. The inner trochlea is elevated above the
others and is thrust relatively strongly backward and slightly
inward. The inner intertrochlear notch is about 2 mm deeper
than the outer. In side view the acrotarsial edges of the middle
and outer trochleae are raised only slightly above the level of
the shaft.

Posteriorly, no articular facet for digit I is visible; there-
fore, this toe was absent or greatly reduced. The plantar sur-
face of the shaft is slightly concave between the bases of the
trochleae. Some 9 mm above the center of the middle trochlea,
and + mm dorsomedial to the distal foramen, is a relatively
large subtriangular pit, about 4 mm in maximum diameter,
which passes obliquely dorsally into the shaft. It does not seem
to be a pneumatic foramen for no comparable foramen was
seen in any of those birds with pneumatic tarsometatarsi. The
closest approximation to such a structure were one or more
much smaller foramina in the same location seen in numerous
members of a variety of orders. These foramina presumably
mark the attachment areas of stout ligaments binding sesamoid
bones in the living species, and perhaps the foramen in the fossil
had a similar function.

Immediately below this foramen is a low ridge which passes
ventromedially on to the lateral surface of the inner trochlea.
This ridge forms the upper boundary of a pitted depression on
the plantar surface of the intertrochlear space and the postero-
medial surface of the base of the middle trochlea. A roughened
scar on the outer half of the latter, which terminates distally at
a pair of well-developed pits just above the articular surface,
bounds the depression laterally. This rather prominent depres-
sion probably held a large sesamoid which was anchored in
place by strong ligaments. A similar depression is described by
Brodkorb (1963c) in the Cretaceous gavuform Lonchodytes.

12 Postilla Yale Peabody Museum No. 83

The distal foramen is low, the ventral margin of its acrotar-
sial opening being 4 mm above the articular surface of the
middle trochlea. It is oval, of moderately large size, and ori-
ented at a distinct angle to the axis of the shaft. Its plantar
opening is between the bases of the middle and outer trochleae.
The small foramen for extensor brevis digiti quarti passes from
just inside the anteroventral end of the distal foramen to open
distally between the middle and outer trochleae. A short faint
groove for the extensor tendon passes upward from the outer
half of the distal foramen for about 4.5 mm and merges into
the surface of the shaft.

By far the greatest similarity of this specimen is to the pro-
cellaruforms. However, as Palaecochenoides was believed by
Shufeldt (1916) to be allied to the anseriforms and by Wet-
more (1917) to the pelecaniforms, it is also compared with
members of these orders.

The rather broad, somewhat anteroposteriorly compressed,
and smoothly rounded shaft is similar to that of Diomedea, and
unlike either the similarly shaped but strongly ridged and
grooved shaft of Pelecanus or the smooth but more slender and
rounded shafts of the anseriforms. It is quite distinct from the
extremely flattened shaft of Sula. The relative lengths of the
trochleae are most nearly duplicated in the smaller procel-
lariiforms, especially Fulmarus. In Diomedea the inner trochlea
is nearly as long as the outer, while in the ducks it is generally
quite short and very high on the shaft. In the pelecaniforms the
inner trochlea is longer than the outer, and may, as in Sula,
be the longest of the three. The alignment of the outer and
middle trochleae in a transverse plane is seen only in the smaller
procellariiforms ; in Diomedea and in the other orders examined
the outer trochlea has a moderate thrust toward the plantar
surface.

In most features of the individual trochleae the fossil is very
different from the pelecaniforms and most resembles the procel-
lariiforms. The middle trochlea is broader than in Diomedea,
and much broader than in the other members of the order, but
the low rims of the articular facet separated by a broad groove
are virtually identical to these features in the procellariuforms.
In the pelecaniforms this articular facet is quite different,

July 15, 1964 Miocene Birds from South Carolina 13

having high swollen rims and a deep median groove. A distinctly
grooved inner trochlea is also like the procellariforms, and
unlike the pelecaniforms in which the articular surface is
rounded or very feebly grooved.

The absence of a facet for the first digit is like Diomedea,
and unlike the pelecaniforms in which the facet is generally
strongly developed. The strong ridge on the anterior face of
the shaft is not found in any living form examined, though, as
Dr. Alexander Wetmore (in litt.) has pointed out, a similar
structure is faintly indicated in Diomedea.

The distal foramen is less like that of either the procel-
laruforms or the pelecaniforms than it is like that of the
anseriforms, being very low, oblique, and opening posteriorly
between the outer and middle trochleae. In general, it is lower
in the pelecaniforms than in the procellariiforms, but it is more
obliquely oriented in the latter. It differs from that of anseri-
forms in being flush with the anterior surface of the shaft, as
it is in Diomedea, rather than being depressed in a shallow
sulcus.

To summarize these facts, the MCZ tarsometatarsus is
matched most closely in general shape and surface features by
the comparable element in Diomedea, though in relative propor-
tions cf the trochleae it is almost identical to Fulmarus. It
shows no distinctly pelecaniform, as opposed to procellariuform,
features except an apparently strong pneumaticity. The only
feature in which it most nearly resembles the anseriforms is the
low, oblique distal foramen.

In addition, the specimen has several characters either com-
pletely lacking or only feebly developed in any of the above
orders. These are: (1) the strong ridge on the anterior face of
the shaft; (2) the prominent foramen on the plantar surface;
and (3) the pitted depression between the plantar faces of the
middle and inner trochleae. All of these features, apparently
related as they are to tendons and sesamoids of the foot, sug-
gest that the living bird had powerfully developed toes.

The possible relationship of Palaeochenoides to the pseu-
dodontorns will be discussed in a final section after the deserip-
tion of the second tarsometatarsus from the phosphate beds.

14 Postilla Yale Peabody Museum No. 83

Famiry CYPHORNITHIDAE?

Tympanonesiotes* wetmorei,* new genus and species

Figure 3

Type: Distal portion of right tarsometatarsus, USNM
16809.

Horizon and Locality: Hawthorne Formation. From the
Cooper River, near Drum Island, Charleston, South Carolina.

Diagnosis: Tentatively referred to the family Cyphorni-
thidae on the basis of its similarity to the ?Palaeochenoides
mioceanus tarsometatarsus (MCZ 2514), which it resembles in:
its relatively broad flat shaft expanding gradually into bases
of trochleae; relative proportions of its trochleae (as pre-
served) ; its low distal foramen opening posteriorly between
bases of trochleae III and IV; short ridge on anterior surface
of its shaft; pronounced hollow on plantar surface between
trochleae II and III.

It is distinguished from Palaeochenoides? in: being about one
fourth smaller in size; having distal foramen lower and con-
tained in deep sulcus; having anterior surface of trochleae III
and IV raised more abruptly and to a greater height above
level of shaft. It is distinguished from Cyphornis by its much
smaller size, from Osteodontornis and Pseudodontornis, less
certainly, by its smaller size.

The specimen consists of the anterior face of the distal end
of the tarsometatarsus with the basal sections of the three
trochleae. The posterior surface with the exception of the base
of the middle trochlea is missing.

The very thin wall of the shaft indicates that this element
was pneumatic. The lower end of the shaft is relatively flat with
the lateral portions gently rounded toward the back. Inside
the median line of the shaft, about 15 mm above the upper

*From Greek tympanon (drum) and nesiotes (feminine, islander).

‘Named in honor of Dr. Alexander Wetmore.

eh

July 15, 1964 Miocene Birds from South Carolina 1

Or

\- =o ~

Figure 3. Tympanonesiotes wetmorei gen. et sp. nov., USNM 16809, right
tarsometatarsus. A. Acrotarsial view. B. Medial view. X 1.

edge of the middle trochlea, are a pair of short ridges which
form a narrow sulcus between them. The more medial is a
heavy ridge some 8 mm long which corresponds to the similar
raised area on the shaft of the Palaeochenoides? tarsometa-
tarsus. The outer raised line is very faint in T'ympanonesiotes
and is not evident at all in the larger specimen. The sulcus,
according to Dr. Wetmore (in litt.), “evidently guided a ten-
don that controlled the inner toe. The indication, therefore,
is that the rather elevated second toe was capable of active
movement.” The width of the shaft at the base of the heavier
ridge is 16.1 mm.

The outer two trochleae lie in the plane of the shaft. The
inner is inflected slightly posteriorly, and is elevated above the
level of the other two, its upper margin being on a line with the
upper margin of the distal foramen. Details of the trochleae,
insofar as they are preserved, are nearly identical to these
parts in the MCZ specimen. In T'ympanonesiotes the anterior
surface of the middle and outer trochleae are raised more
sharply above the level of the shaft. The preserved width
through the trochleae is 24.5 mm.

The distal foramen is contained in a shallow sulcus with a
short groove presumably for extensor brevis digiti quarti,
extending upward for 5 mm to merge with the surface of the

16 Postilla Yale Peabody Museum No. 83

shaft. Below the distal foramen the sulcus deepens, extending
between the middle and outer trochleae. Possibly the extensor
tendon lay in this sulcus rather than having been enclosed in a
distinct foramen, the presence or absence of which cannot be
determined in this specimen.

Enough of the plantar surface is preserved to show that the
distal foramen opens posteriorly between the bases of the mid-
dle and outer trochleae. On the inner half of the middle troch-
lea, continuing into the intertrochlear space, is a roughened
depression lke that seen in Palaeochenoides?. It is bounded
above by a shelf passing upward and outward from the inner
trochlea to the extreme base of the middle trochlea.

In his notes Dr. Wetmore writes: “The only hint of possible
relationship that has come from this latest study is a faint
resemblance to what is found in the albatrosses.”” Mainly on
the basis of the mcre complete MCZ specimen I had also arrived
at the similar conclusion that the closest resemblance of these
two tarsometatarsi is to Diomedea. The Palaeochenoides? bone,
however, is in general less specialized and more albatross-like
than is that of T’ympanonesiotes.

RELATIONSHIPS OF THE PHOSPHATE BEDS BIRDS

With regard to the possible ordinal relationships of the two
tarsometatarsi described above, the following conclusions may
be drawn: (1) they show definite resemblances to the Procel-
lariformes except for being highly pneumatic; (2) they show no
definite resemblances to the Pelecaniformes, with the exception
of an apparently high degree of pneumaticity; (8) the larger
specimen resembles in size and pneumatic character a femur,
the type of Palaeochenoides mioceanus, from the same forma-
tion and a nearby locality, which, however, is distinctly pele-
caniform and not procellariiform in morphology: and (4)
Pseudodontornis longirostris, a large bird comparable in size
to P. mioceanus and a member of a family which shows a com-
bination of pelecaniform and procellariform features also oc-
curs in the same beds as all of the above-mentioned specimens. It
therefore seems probable that Palaeochenoides and Pseudodon-
tornis are synonymous (the former name having priority).

July 15, 1964 Miocene Birds from South Carolina 17

Unfortunately, confirmation of this hypothesis by comparing
the Hawthorne limb bones with the type skeleton of Osteodont-
ornis cannot yield conclusive results for the leg bones of that
specimen are so crushed that none but the grossest features can
be made out with any certainty. However, Howard (1957) does
note the probable absence of digit I in this specimen, a point of
similarity to ?P. mioceanus and a distinct difference from the
pelecaniform birds. Inasmuch as the evidence suggesting the
identity of Palaeochenoides and Pseudodontornis is as yet by
no means conclusive, I await further knowledge of well-pre-
served associated skeletal parts before proposing formal nomen-
clatural changes.

Yn recent classifications (Wetmore, 1960; Brodkorb, 1968b)
the pseudotoothed birds have been placed as a suborder of the
order Pelecaniformes. Howard (1957), however, as a result of
her study of the relatively complete skeleton of Osteodontornis
concluded that the three genera of “toothed” birds show enough
similarities to both the Pelecaniformes and Procellariformes
in combination with quite distinctive characteristics of their own
to merit placement in a separate order Odontopterygiformes
(proposed by Spulski, 1910, as Odontopterygia). Wetmore
(1960), on the basis of a restudy of the skull of Odontopteryx,
prefers to retain the group in the Pelecaniformes. If the
Hawthorne tarsometatarsi do pertain to pseudodontorns they
strengthen Howard’s argument that the odontopterygians show
enough non-pelecaniform features to require being placed in
an order of their own.

Whether or not the Odontopterygia should be raised to the
status of order, I suggest that the family Cyphornithidae be
added to its included families (see Brodkorb, 1963b, for the
most recent classification of this group). This allocation of the
Cyphornithidae, in which I would include Cyphornis, Palaeo-
chenoides, and, less certainly, T'ympanonesiotes, is necessarily
provisional, but it is preferable to that of Brodkorb (1968b),
in whose classification this family is placed in the suborder
Cladornithes. This possibly pelecaniform suborder was erected
by Wetmore (1960) to contain Cladornis pachypus Ameghino
(1895), a peculiar broad, anteroposteriorly compressed tar-

18 Postilla Yale Peabody Museum No. 838

sometatarsus from the Oligocene of Patagonia. Brodkorb’s rea-
son for including the Cyphornithidae in the suborder Clador-
nithes was the presence in the same beds with Palaeochenoides
cf the tarsometatarsus described herein as T'ympanonesiotes
wetmoret (USNM 16809), which he believed bore a resemblance
to Ameghino’s figure of Cladornis (Brodkorb, pers. comm.).
With additional preparation and with the more complete MCZ
tarsometatarsus taken into account, it is clear that T'ympano-
nesiotes is quite different from Cladornis and sheds no light
whatsoever on the possible affinities of the Patagonian fossil.
The subcrder Cladornithes is best returned to its uncertain
position at the end of the order Pelecaniformes, where it was

placed by Wetmore (1960).

REFERENCES

Allen, G. M., 1926. Fossil mammals from South Carolina. Bull. Mus. Comp.
Zool., v. 67, no. 14, p. 447-467, 5 pl.

Ameghino, F., 1895. Sur les oiseaux fossiles de Patagonie. Boletin del
Instituto Geografico Argentino, tome 15, cahiers 11-12, p. 1-104, 44 fig.

Brodkorb, P., 1963a. Miocene birds from the Hawthorne Formation. Quart.
Jour. Florida Acad. Sci., v. 26, no. 2, p. 159-167, 1 pl.

, 1963b. Catalogue of fossil birds: Part 1 (Archaeopterygi-
formes through Ardeiformes). Bull. Florida State Mus., v. 7, no. 4, p.
179-293.

—_————.,, 1963c. Birds from the Upper Cretaceous of Wyoming. Proc.
XI1Ith Internat. Ornith. Congr. Ithaca, p. 55-70, 10 fig.

Howard, H., 1957. A gigantic “toothed” marine bird from the Miocene of
California. Bull. Dept. Geol., Santa Barbara Mus. Nat. Hist., no. 1, p.
1-23, 8 fig.

, and J. A. White, 1962. A second record of Osteodontornis,

Miocene “toothed” bird. Los Angeles County Mus. Contr. in Science,

no. 52, p. 1-12, 5 fig.

Lambrecht, K., 1930. Studien iiber fossile Riesenvégel; I Pseudodontornis
n.g. Geol. Hungarica, ser. pal., fase. 7, p. 1-17, 6 fig., 2 pl.

Owen, R., 1873. Description of the skull of a dentigerous bird (Odontop-
teryx toliapica Ow.) from the London Clay of Sheppey. Quart. Jour.
Geol. Soc. London, v. 29, p. 511-522, 2 pl.

Shufeldt, R. W., 1916. New extinct bird from South Carolina. Geol. Mag.,
n.s., V. 3, p. 343-347, 1 pl.

Simpson, G. G., 1932. Fossil Sirenia of Florida and the evolution of the
Sirenia. Bull. Amer. Mus. Nat. Hist., v. 59, p. 419-503, 23 fig.

Spulski, B., 1910. Odontopteryx longirostris n. sp. Zeitschr. d. Deutsch Geol.
Ges. Monatsber., p. 507-521, 7 fig.

July 15, 1964 Miocene Birds from South Carolina 19

Wetmore, A., 1917. The relationships of the fossil bird Palaeochenoides
, 1928. The systematic position of the fossil bird Cyphornis
magnus. Geol. Surv. Canada Mus. Bull., no. 49, p. 1-4, 1 fig.
———___—., 1960. A classification for the birds of the world. Smithsonian
Mise. Coll., v. 139, no. 11, p. 1-37.

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