JEFFERSONIANA

Contributions from the
Virginia Museum of Natural History

Number 11

February 30, 2003

A REVIEW OF THE EASTERN NORTH
AMERICAN SQUALODONTIDAE
(MAMMALIA: CETACEA)

Alton C. Dooley, Jr.

Jeffersoniana, Number 1 1, pp. 1-26
Virginia Museum of Natural History, 2003

A Review of the Eastern North American Squalodontidae

(Mammalia: Cetacea)

Alton C. Dooley, Jr.

Virginia Museum of Natural History
Martinsville, Virginia 24112, USA

He saw that in this dusty and fathomless matter of learning the true name of
every place, thing, and being, the power he wanted lay like a jewel at the
bottom of a dry well. For magic consists in this, the true naming of a thing.
So Kurremkarmerruk had said to them, once... “Many a mage of great
power, ” he had said, “has spent his whole life to find out the name of one
single thing — one single lost or hidden name. And still the lists are not
finished. Nor will they be, till world’s end.

...Ursula K. LeGuin, A Wizard of Earthsea

ABSTRACT

Previous listings of species of the cetacean family
Squalodontidae give the appearance of a diverse, well-
represented group, but nearly all of the named specimens
from North America are based on extremely poor material
or were improperly proposed. This paper reviews the
descriptions of these species and their type specimens to
determine their validity.

Of 16 species from North Arnerica examined in the
study, only two are members the family Squalodontidae,
and only one, Squalodon calvertensis Kellogg, 1923, is
based on material sufficient for reliable identification. An
additional unnamed squalodont species is identified. Thus
the diversity of Miocene Squalodontidae in North America
was much lower than has been indicated in the literature.

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INTRODUCTION

The Squalodontidae are a family of extinct odontocete cetaceans,
found principally in Europe and eastern North America in late Oligocene
to middle Miocene age strata. Two factors have led to some confusion
about the status of this family. First, fossil remains of squalodonts are
relatively rare, and often are very fragmentary; there is not even a
complete composite skeleton for any species of squalodontid. Second,
squalodonts are rather primitive compared to their Miocene
contemporaries. These factors have led to the family becoming a “catch-
all” for almost any poorly preserved primitive whale of Miocene age.
Some species and specimens have been questionably referred to the
Squalodontidae, resulting in a confused nomenclature that is in need of
clarification.

A number of authors have reviewed squalodontid nomenclature,
most significantly Kellogg (1923), Rothausen (1968), Ray (1976),
Muizon (1991, 1994), and Fordyce (1981). This paper is an examination
of the North American specimens that have been referred to
Squalodontidae or at one time or another been considered to be
squalodontids. By 1926 there were 16 type specimens from deposits in
eastern North America referred to the Squalodontidae.

Muizon (1991, 1994) and Fordyce (1981, 1994) have attempted to
restrict the definition of the Squalodontidae. Based in part on their work,
the following characters are suggested as Squalodontidae apomorphies.
1) a spongy posterior process of the tympanic bulla; 2) reduction ot the
lateral lamina of the pterygoid hamulus (as in Muizon, 1991, 1994); 3) an
upturned rostrum and mandible, 4) incisors that are nearly circular in
cross section throughout their length, and straight with serrate edges, 5)
an upper II alveolus that lies directly dorsal to the upper 12; 6) teeth that
are serrate with heavily ornamented enamel from the base to the apex,
increasing on posterior teeth, with ornamentation consisting of short
ridges (the aristae rugosae of Rothausen, 1968), extending toward the
apex, each ridge extending approximately 5 mm or less; and 7) cervical

T

Dooley: Squalodontid nomenclature 3

vascular sinuses on Ce4-Ce6 only. Another important feature of the
Squalodontidae, though not an apomorphy, is the degree of telescoping.

In squalodontids the posterior ends of the maxillae are nearly in contact
with the supraoccipital, and the parietals are almost (or completely)
covered in dorsal view. Genus-level and species-level characters are not
considered in this paper, and will be addressed in a future study.

Institutional abbreviations: AMNH = American Museum of Natural
History; ANSP = Academy of Natural Sciences of Philadelphia; MCZ =
Museum of Comparative Zoology, Harvard University; USNM =

National Museum of Natural History, Smithsonian Institution

SAUROCETUS GIBBESII Agassiz, 1848

Saurocetus gibbesii Agassiz, 1848 is based on a single cheek tooth,
possibly from late Oligocene deposits of South Carolina (MCZ 8760;
Figure 1). The tooth has very simple ornamentation with no cristae
rugosae, excluding it from the Squalodontidae. My examination of
undescribed specimens in the Charleston Museum suggests that it has
affinities with “Genus Y” of Whitmore and Sanders (1977), from late
Oligocene beds near Charleston. “Genus Y” has less complete
telescoping than do the squalodontids, and the taxon apparently
represents a more primitive cetacean. Until more complete material is
discovered, Saurocetus gibbesii should be placed in Odontoceti incertae
sedis.

AGOROPHIUS PYGMAEUS (Muller), 1849

Agorophius pygmaeus (Muller), 1849 is based on a skull and tooth
from late Oligocene deposits of South Carolina, which were originally
figured by Tourney (1847) as “a cranium of the Zeuglodon.” It was
transferred to the genus Squalodon by Leidy (1869), but Cope (1895)
erected the genus Agorophius for this species, and the family

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Agorophiidae was established by Abel (1914). Whitmore and Sanders
(1977) classified as Odontoceti incertae sedis. The holotype

I

Figure 1. Saurocetus . Agassiz, 1848. Holotype, MCZ 8760,

tooth. Scale = 10 mm.

skull of A. pygmaeus has been lost, but Fordyce (1981) redescribed the
species based on figures of the holotype, and resurrected the
Agorophiidae. Agor ophius is much more primitive than any
squalodontid, with less pronounced telescoping of the cranium and a
prominent intertemporal constriction. The teeth have much less
ornamentation than is observed in the squalodontids (Fordyce, 1981).
Fordyce (1981) excluded the Agorophiidae from the Squalodontoidea
(the superfamily which includes the Squalodontidae) because of its lack
of any synapomorphies shared with the squalodontids.

COLOPHONODON HOLMESII Leidy, 1853b

Colophonodon holmesii Leidy, 1853b was based on a tooth from
South Carolina. Cope (1867b) transferred this species to Squalodon, and
Kellogg (1923) noted that the species is represented by one nearly
complete tooth and fragments of five others. Leidy (1869) suggested that
the teeth may be related to Agorophius, but Kellogg (1923) stated that

Dooley: Squalodontid nomenclature

5

"The remains are altogether too incomplete to propose any definite
allocation in the light of or present knowledge of the fauna of these
phosphate deposits". This statement is academic now, as the holotype
specimen has apparently been lost. Kellogg (1923) thought that the
holotype material was “possibly in the Academy of Natural Sciences at
Philadelphia” but Gillette (1975) and Spamer et al. (1995) did not list
these specimens among the types housed in the Academy, and I have
been unable to locate them.

MACROPHOCA ATLANTICA Leidy, 1856a

Macrophoca atlantica Leidy, 1856a was based on three teeth (ANSP
11217, 11218, and 11219) from Cumberland County, New Jersey (Figure
2). These teeth are not definitely from the same individula, and as Leidy
did not designate one tooth as the type, ANSP 11218 (the tooth with 2
complete roots) is herein designated as the lectotype, with ANSP 11217
and ANSP 1 1219 as paralectotypes.

Cope (1867a) listed Squalodon atlanticus among remains from the
Thomas collection, discovered in Charles County, Maryland, citing
Leidy as the author of this species; “ ... a fragment of the muzzle,
including the proximal portions of the maxillary bones, with molars, and
the canine teeth of the Squalodon Atlanticus (Leidy).” Cope (1867b)
later clarified this referral with a more detailed description:

Squalodon Atlanticus Leidy MS. Macrophoca atlantica
Leidy, Proceed. Acad. 1856^ 220.

Remains of three individuals of this species
before me indicate considerable variety in the forms of
the two rooted molar teeth.

The individual from which Leidy determined the
species is represented by only three true molars....

The second individual is represented in the
Thomas collection by the proximal portions of the

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maxillary bones of both sides, and seven molar teeth in
place....

The third individual is represented by one true
molar, and two caniniform premolars....

No. 1 was discovered in the miocene of New
Jersey; the others were in the Thomas collection.

The “second individual” described by Cope are ANSP 11220 and
11221 (Figure 3a-d). This is also the specimen mentioned by Cope
(1867a) in his earlier reference to S. atlanticus. However, there has been
some uncertainty concerning the status of ANSP 11221. Case (1904)
figured a maxilla fragment as S. atlanticus (Figure 3e), with the
following caption:

Figs. 1-3 Squalodon atlanticus Leidy

1. Portion of the right side of a jaw containing
three teeth. Shiloh, N. J. Acad. Nat. Sci.,

Phila.

This specimen is clearly ANSP 11221, the maxilla fragment from
Charles County, Maryland described by Cope (16867a, 1867b) (compare
Figures 3c and 3e). The caption reference to Shiloh, New Jersey was in
error. As Leidy’s original specimens were from New Jersey this has
apparently led some workers to believe that ANSP 11221 was the type
specimen. For instance, Spamer et al. (1995) cited Case (1904) with the
following note: “ The holotype teeth [of Squalodon atlanticus] in jaw
fragment are illustrated in [Plate 10] fig.l.”

Allen (1916) referred S. atlanticus to Basilosaurus but Kellogg
(1923) correctly noted that there was no basis for this action, and he
returned the species to Squalodon. I have examined both Leidy’s
holotype teeth and Cope’s referred specimens. They are typical of
squalodont teeth as described in character 6 above, and they can thus be
considered as belonging in the Squalodontidae. As mentioned by Kellogg

Dooley: Squalodontid nomenclature

7

A

Figure 2. Squalodon atlanticus. A. ANSP 11217 (paralectotype), B.
ANSP 1 1218 (lectotype), C. ANSP 1 1219 (paralectotype), teeth. Scale
= 10 mm.

C

Figure 3. Squalodon sp., ANSP 1 1220, maxillary fragment, A. lateral, B.
ventral. ANSP 11221, maxillary fragment, C. lateral, D. ventral. Scale =
50 mm. E. Case (1904), Plate 10, Figure 4. Compare Figure 3c and
Figure 3e.

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(1923), S. atlanticus is quite similar to S. calvertensis. Because of their
extreme variability in cetaceans, teeth are of limited value in identifying
specimens below the family level. Thus S. atlanticus should be placed in
Squalodontidae incertae sedis. Cope’s mandible fragments (ANSP 11220
and 11221) should therefore not be referred to S. atlanticus but are
instead considered Squalodon sp. until their affinities can be determined.

SQUALODON MENTO Cope, 1867a

Squalodon mento Cope, 1867a was based on four teeth from the
Miocene of Charles County, Maryland. According to Cope (1867a) they
“were between two and three times as large as those belonging to
Squalodon wymanii {Phoca of Leidy)”.

Figure 4. Squalodon mento Cope, holotype, A. ANSP 1 1228, B. ANSP
1 1229, and C. ANSP 1 1230. Scale = 10 mm.

Cope (1867b) later referred some of Wyman’s (1850) specimens
from Richmond, VA to this species, although he apparently had some
doubts as to whether Wyman’s material was closer to S. mento or S.
wymanii:

Squalodon mento Cope. Cetacean, Wyman, Amer.

Jour. Sci. Arts, 1850, 230-232, figs. 4, 5, 6, 7.

A tooth, perhaps occupying that place [the
“transitional molar”] or the next, has been figured by Dr.

Dooley: Squalodontid nomenclature

9

Wyman (Supra fig 4), as belonging to the genus
Phocodon Agass. The anterior premolars and a portion
of the mandible, no doubt belonging to the same species,
are figured in the same place as above. They belong to
an animal much smaller than that to which the teeth
above described pertain, and it is a matter of some
question whether these specimens do not rather relate to
the S. wymanii Leidy.

Later, Leidy (1869) referred this species to the genus Delphinodon,
as Delphinodon mento. Spamer et al. (1995) indicate that ANSP 1 1228,

1 1229, and 1 1230 are the holotype material of S. mento (Figure 4), with a
note that a fourth tooth is missing. Only one of these teeth (ANSP 1 1229-
Figure 4 B) shows any similarity to the teeth of squalodonts, although the
amount of enamel ornamentation, as well as the relatively short crown
compared to the overall length of the tooth, are more similar to the
kentriodontid Hadrodelphis calvertense. Dawson (1995) considered one
of these teeth (apparently ANSP 1 1228) to be similar to, but still distinct
from, Hadrodelphis calvertense. Until its affinities can be determined,
Delphinodon mento should be placed in Odontoceti incertae sedis.

This leaves Wyman’s (1850) specimens from the Calvert Formation
of Richmond, Virginia (Figure 5). One tooth (Wyman, 1850: fig. 4),
which he called Phocodon, apparently is ANSP 1 1227, the holotype of
Phocagenus venustus Leidy 1869, although as noted by Leidy (1869)
Wyman’s figure is not very similar to the actual tooth. The other teeth
figured by Wyman (1850: figs. 7a-7c) and referred to S. mento by Cope
(1867b) have apparently been lost (Spamer et al. 1995). Based on
Wyman’s figure, these teeth bear no resemblance to any squalodont
tooth; the teeth shown in his Figures 7a and 7b seems somewhat similar
to Phocagenus venustus. Also figured is the anterior part of a rostrum
(Wyman, 1850: figs. 5 and 6). Wyman compared it to Phocodon,
Delphinus, and Basilosaurus, and to crocodiles, and thought that it most
closely resembled Delphinus. In fact, his figure closely resembles the

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mandible of Squalodon calvertensis , Unfortunately, I have been unable
to locate this specimen.

Figure 5. Wyman’s (1850) figures 1-8, p.232 of American Journal of
Science, VIO No. 29.

Dooley: Squalodontid nomenclature

11

SQUALODON PROTERVUS Cope 1867b

Squalodon protervus Cope 1867b was based on a single tooth
(ANSP 1 1543a) from Charles County, Maryland. In the same paper in
which Cope named S. protervus, he also referred the species to Cynorca,
creating the name Cynorca proterva. Cope listed two other teeth (ANSP
10326 and 10327) in the description of S. protervus, but the holotype was
clearly the single tooth. Later, Cope (1868) assigned ANSP 1 1543a to
the peccaries:

In the description of Cynorca proterva...!
unfortunately mingled with its molar and premolar teeth
(ANSP 10326 and 10327) the canine of [a] small
Dicotyles. This point, suggested to me by Leidy, I have
no doubt is the case.

As pointed out by Spamer et al. (1995), as the canine referred to
Dicotyles was the holotype of Cynorca proterva, this forms the binomen
Dicotyles protervus.

Leidy (1869) discussed ANSP 1 1543a under the name Dicotyles
lenis. The other two teeth described by Cope (ANSP 10326 and 10327)
as well as two additional teeth from South Carolina (ANSP 10328 and
10329) Leidy considered as Squalodon protervus. In addition, as Kellogg
(1923) pointed out:

“The tooth mentioned above [Squalodon protervus
or Cynorca proterva of Cope] was clearly designated as
the type by Cope, and since it was originally described
as a species of the genus Squalodon, it invalidates any
subsequent use of this specific name in this genus. There
are four teeth, however, labeled with this name, from
Ashley River, South Carolina, in the Academy of

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Natural Sciences in Philadelphia [ANSP 10326-10329].

Two of these teeth are figured by Leidy and described
under the name of Squalodon protervus. Whatever the
determination of this last mentioned material may
eventually prove to be, it is evident that the use of the
specific name protervus in this sense is invalid.”

These teeth are very small, and their ornamentation pattern is
different than that described in character 6 as a squalodont apomorphy.
Thus, neither S. protervus Cope nor the teeth listed as S. protervus by
Leidy is squalodont. As the holotype (and only the holotype) of S.
protervus Cope has been placed among the peccaries, ANSP 10326-
10329 are not currently assigned to any species.

PHOCA WYMANI Leidy, 1853a and
SQUALODON WYMANII Cope, 1867b

The history of Phoca wymani Leidy, 1853a was traced in detail by
Ray (1976). The type specimen, consisting of cranial fragments, was
collected from the Calvert Formation at Richmond, Virginia, by Wyman,
and described but not named by him in 1850. Leidy (1853a) named this
specimen Phoca wymani, and subsequently (Leidy, 1856b) reported a
tooth, “apparently an inferior canine,” from the Miocene of Virginia and
referred it to P. wymani (Figure 6).

Cope ( 1 867b) removed this tooth from Phoca and made it the type of
a new species, Squalodon wymanii. Cope also mentioned three other
teeth supposedly belonging to this species but clearly designated Leidy's
tooth (ANSP 1 1225) as the type:

Of this, the smallest species of the genus, three
premolar teeth [ANSP 11222, 11223, and 11226] are in
the collection, and the type specimen [ANSP 11225] is
in the Academy's Museum. The teeth are remarkable for

Dooley: Squalodontid nomenclature

13

the abrupt posterior direction of their crowns. The roots
are curved, one of them abruptly so, and flattened.

Leidy (1869) acknowledged that these teeth were indeed cetacean
but differed with Cope in his interpretation, and referred S. wymanii to
Delphinodon:

Three teeth, from the miocene formation of Charles
County, Maryland, ascribed by Prof Cope to a species
of Squalodon, appear to me, at least in part, to belong to
a smaller species of Delphinodon.

One of the teeth ... bears a resemblance to that first
described of the larger species....

A tooth ... from the miocene formation of Virginia,
originally ascribed by me to the same species as the
remains of a Seal described by Prof Wyman, is very like
the one above indicated. ...The remaining two teeth from
Charles County, ascribed by Prof. Cope to Squalodon
Wymani, are different from the proceeding, and it is
uncertain whether they belong to the same animal.

To further confuse matters, Hay (1902) renamed the material, stating
that “... the name Delphinodon leidyi is intended to replace D. wymani
Leidy ...The type of D. leidyi is Leidy, J.1869 A, pi. XXX, fig. 12”
[ANSP 11225]. As Ray (1976) noted;

The new name must have been proposed under the
erroneous belief that Phoca wymani and Delphinodon
wymanii were specific homonyms, which they were not
and are not. In my opinion Delphinodon leidyi was an
unnecessary replacement name and should be relegated
to the junior synonymy of Delphinodon wymanii.

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Thus, Squalodon wymanii consisted of the holotype tooth (ANSP
1 1225) and three referred specimens (ANSP 1 1222, 11223, and 1 1226),
two of which (including the holotype) Leidy placed in Delphinodon.
With the referral of the holotype specimen to Delphinodon, there is no
holotype specimen of Squalodon wymanii, and the two referred teeth that
Leidy did not assign to Delphinodon are not currently with any genus.

The holotype tooth of Delphinodon wymanii and the unnamed teeth
originally referred to S. wymanii are all much smaller than any known
squalodontid specimen and their shape is inconsistent with any
squalodontid teeth. The crowns of these teeth are recurved and nearly
circular in cross section, but the only squalodont teeth that are nearly
circular in cross section are the incisors, which are very large and not
recurved. Thus, Delphinodon wymanii and the unnamed specimens do
not appear to be members of the Squalodontidae and should be placed in
Odontoceti incertae sedis until their affinities can be determined.

Figure 6. Delphinodon wymanii (Cope) 1867, ANSP 11225, holotype
tooth. Scale = 10 mm.

PHOCA DEBILIS Leidy, 1856b and
SQUALODON DEBILIS Cope, 1867b

Phoca debilis Leidy, 1 856b was described on the basis of three teeth
from the Ashley River in South Carolina. Cope (1867b) referred this
species to Squalodon, and later Kellogg (1923) tentatively assigned it to

Dooley: Squalodontid nomenclature

15

Delphinodon. In Cope’s (1867b) referral, however, he did not mention
the type specimens, refer to Leidy's description of Phoca debilis, nor
even mention S. debilis in the text, although the other five squalodonts
that he listed are all discussed. I can find no reference to S. debilis earlier
than 1867 and, because no type is designated Squalodon debilis does not
meet the requirements of Articles 12 and 16 of the International Code of
Zoological Nomenclature and the species is therefore a nomen nudum.

The type teeth of Phoca debilis formerly were ANSP 10322, 10324,
and 10325. ANSP 10322 later became the type of Phoca modesta (see
below). Gillette (1975) listed the type of Phoca debilis as ANSP 10324
and 10325, "3 teeth, present," but in my examination of the teeth only
two were present. Neither bears any resemblance to any squalodont
tooth.

PHOCA MODESTA Leidy, 1869

The history of Phoca modesta Leidy, 1869 is entwined with that of
Phoca debilis. As mentioned above, Leidy (1869) designated one of the
type teeth of Phoca debilis as the type of Phoca modesta, but he thought
that it may have represented a squalodontid. The holotype is ANSP
10322 and, according to Gillette (1975), ANSP 10323 is a paratype
(Figure 7). Allen (1880) referred this species to Squalodon, as Squalodon
modestus. Kellogg (1923) was of the opinion that the teeth were from a
pinniped. These teeth do not meet the characteristics described in
character 6. They are much smaller than any known squalodontid tooth,
and the enamel ornamentation is much less prominent and complex. Ray
(1976) stated:

In my opinion both taxa [Phoca debilis and Phoca
modesta] represent small porpoises, neither Delphinodon
nor Squalodon, whose affinities may or may not be
determinable by thorough comparison with other taxa,
including modern representatives, but which in any
event are not pinnipeds.

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Thus, the referral of this species to Squalodon should be rejected,
and '"Phocd’' modesta should be assigned to Odontoceti? incertae sedis.

Figure 7. Phoca modesta Leidy, 1869. Holotype, ANSP 10322 (left), and
paratype, ANSP 10323 (right), teeth. Scale = 10 mm.

SQUALODON? PELAGIUS Leidy 1869

Squalodon? pelagius Leidy, 1869 was based on a fragment of the left
maxilla with a cheek tooth in situ, from the Ashley River near
Charleston, South Carolina. Kellogg (1923) stated that the holotype is in
the Academy of Natural Sciences of Philadelphia, but Gillette (1975) and
Spamer et.al (1995) did not list it among the Academy’s collections, and
1 have been unable to locate it. Fordyce (1981) thought that this tooth
was similar to that of Xenorophus sloanii. At present, this specimen is
best placed in Odontoceti incertae sedis.

GRAPHIODON VINEARIUS Leidy, 1870

Graphiodon vinearius Leidy, 1870 was based on a tooth from
Martha’s Vineyard, Massachusetts (Figure 8). Cope referred it to
Squalodon in 1890. Kellogg (1923) was of the opinion that this tooth
might be from a physeterid. This specimen has a conical crown with and

Dooley: Squalodontid nomenclature

17

inflated root, and is quite similar to other physeterid teeth. G, vinearius
should be placed in Physeteridae? incertae sedis.

Figure 8. Graphiodon vinearius \.Q\dy , 1870. Holotype, USNM 875,
tooth. Scale - 10 mm.

CETERHINOPS LONGIFRONS Leidy, 1877

Ceterhinops longifrons Leidy, 1877 was based on a partial cranium
(ANSP 11420; Figure 9) from South Carolina. Leidy considered this
species to be close to the squalodontids. Kellogg (1923) thought that the
specimen was referable to Eurhinodelphis; the size and overall
morphology of ANSP 1 1420 are consistent with this assessment, Sanders
(pers. comm., 2002) has noted the presence of Pliocene sediment in
cavities in this specimen, although it could have been reworked from the
Miocene. Given the similarity of this specimen to Eurhinodelphis, C.
longifrons should be placed in Eurhinodelphidae? incertae sedis.

SQUALODON TlEDEMANl Allen, 1887

Squalodon tiedemani Allen, 1887 was described on the basis of a
large rostral fragment found in a phosphate dredge from the Wando
River at Charleston, South Carolina (AMNH 475; Figure 10). He
referred two mandibular fragments from the same area to this species.
Kellogg (1923) examined the holotype of S. tiedemani but was unable to
decide whether or not this specimen was a squalodontid or an
archaeocete. Incidentally, Kellogg listed this specimen as No. 10445, but

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Figure 9. Ceterhinops longifrons Leidy, 1877. Holotype, ANSP 1 1420,
cranium. Scale = 50 mm.

this was a field number rather than a catalog number. Boreske et al.
(1972) referred a rostrum and mandible fragment from North Carolina to
this species. Dooley (1991) described a skeleton (USNM 183023)
collected in 1975 from the Calvert Formation of Virginia, and referred
this and a number of skull and mandible fragments from the Calvert
Formation of Maryland and Virginia and the Pungo River Formation of
North Carolina to S. tiedemani. However, examination of undescribed
specimens at the Charleston Museum in South Carolina shows that the
holotype specimen of S. tiedemani is very similar to the anterior rostrum
of the late Oligocene “Genus Y” of Whitmore and Sanders (1977),
mentioned above in relation to Saurocetus gibbesii. It is likely that the
holotypes of Saurocetus gibbesii and Squalodon tiedemani are from the
same late Oligocene deposits as “Genus Y”, all being found within a few
miles of each other. The cranial anatomy of “Genus Y” is quite different
from that of USNM 183023, so this material cannot be placed in
Squalodontidae. S. tiedemani should therefore be placed in Odontoceti
incertae sedis. The association of S. tiedemani with “Genus Y” leaves
USNM 183023 and other large squalodont material from the Miocene
without a name. This material represents a currently undescribed species.

Dooley: Squalodontid nomenclature

19

Figure 10. Squalodon tiedemani Alien. Holotype, AMNH 475, rostrum.
A. dorsal, and B. ventral. Scale = 10 cm.

SQUALODON CALVERTENSIS Kellogg, 1923

Squalodon calvertensis Kellogg, 1923 was described on the basis of
a skull, mandible, numerous teeth and five vertebrae (USNM 10484)
from “Zone 6” of the Calvert Formation in Calvert County, Maryland.
To date this is the best-documented squalodont from North America, and
at least five other skulls and hundreds of teeth have been referred to it on
collections labels. Some of the skull, mandible, and tooth remains
mentioned by Kellogg (1923) (USNM 10695) are referable to S.
calvertensis.

SQUALODON CRASSUS Allen, 1926

Squalodon crassus Allen, 1926 was based on a worn fragment of a
mandible with no teeth, from the Oligocene of South Carolina (MCZ
16965; Figure 11). As Allen noted, the specimen is somewhat different

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from the holotype of S. calvertensis, but it does have alveolae for double-
rooted teeth. It is unlikely that this material is diagnostic; the morphology
of this specimen is consistent not only with the Squalodontidae, but also
with many other odontocetes from the Oligocene and Miocene. As it
does not meet any of the listed characteristics of the Squalodontidae, S.
crassus is placed in Odontoceti incertae sedis.

Figure 1 1 . Squalodon crassus. Holotype, MCZ 16965, mandible. A.
dorsal, B. medial, C. lateral. Scale = 10 cm.

SUMMARY

The present status of North American squalodontid nomenclature is
as follows:

Saurocetus gibbesii Agassiz, 1 848. Not a squalodontid, possibly "Genus
Y" of Whitmore and Sanders (1977). Odontoceti incertae sedis.
Squalodon pygmaeus (Muller), 1849, Leidy, 1869 = Agorophius
pygmaeus Muller, 1849. Not a squalodontid. Agorophiidae.
Colophonodon holmesii Leidy, 1853. Holoype lost.

Squalodon atlanticus (Leidy), 1856, Cope, 1867b. Squalodontid, but not
based on species-diagnostic material. Squalodontidae incertae sedis.

Dooley: Squalodontid nomenclature

21

Squalodon mento Cope, 1867a, — Delphinodon mento, Leidy, 1869. Not
a squalodontid, Odontoceti incertae sedis.

Squalodon protervus Cope, 1867b, = Cynorca proterva (Cope), 1876b, =
Dicotyles protervus (Cope), 1868. Not a squalodontid.

Squalodon wymanii Cope, 1867b = Delphinodon wymanii (Cope), 1867,
Leidy, 1869. Not a squalodontid, Odontoceti incertae sedis.
Squalodon debilis Cope, 1867b. Nomen nudum.

Squalodon modestus (Leidy), 1 869. Not squalodontid. ''Phoca'' modesta,
Odontoceti? incertae sedis,

Squalodon? pelagius Leidy, 1869. Type lost? Possibly a xenorophid
(Fordyce, 1981),

Graphiodon vinearius Leidy, 1870. Physeteridae incertae sedis.
Ceterhinops longifrons Leidy, 1877. Not a squalodontid, probably a
eurhinodelphid. Euhrinodelphidae? incertae sedis.

Squalodon tiedemani Allen, 1 887. Not diagnostic. May be “Genus Y” of
Whitmore and Sanders 1 977. Odontoceti incertae sedis.

Squalodon calvertensis Kellogg, 1923. Valid.

Squalodon crassus Allen, 1926. Affinities not yet determined, probably
not a squalodontid. Odontoceti incertae sedis.

Undescribed species, "S. tiedemani " of Dooley, 1991.

Thus, squalodontid diversity in North America is not nearly as great
as it might appear from early species lists. Only one of the 16 earlier
species can be considered a valid squalodont, and it appears that there
were only a small number of species, perhaps only two, living on the
western Atlantic Coast.

ACKNOWLEDGMENTS

This paper is part of a dissertation presented to Louisiana State
University in 1998. I would like to thank my advisor, J. A. Schiebout,
and committee members J. Hazel, J. Wrenn, D. Rossman, D. Hillmann,
and D. Baltz, as well as S. Ting, L. Anderson, and A. Bouma for many
helpful corrections and discussions. The following people provided

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Jeffersoniana

access to specimens at their respective museums: A. Sanders of the
Charleston Museum. C. Schaff of the Museum of Comparative Zoology-
Harvard University, T. Daeschler and N. Gilmore of the Academy of
Natural Science of Philadelphia, J. Alexander at the American Museum
of Natural History , and R. Purdy and D. Bohaska at the Smithsonian
Institution. J. Winston, R. Hoffman, and R. E. Fordyce assisted me with
interpreting the Code of Zoological Nomenclature as applied to 19^^
Century specimens. N. Fraser, L. W. Ward, F. C. Whitmore, Jr., B. S.
Dooley, A. Sanders, and L. G. Barnes all made helpful suggestions. This
research was funded in part by a grant from the L.S.U. Geoscience
Associates.

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