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YALE PEABODY MUSEUM
or Naturat History
Number 64 August 7, 1962 New Haven, Conn.

TWO NEW PRIMATE SPECIES FROM
THE AFRICAN OLIGOCENE

Exwywn L. Simons

One of the major objectives of the Yale 1961-1962 Paleon-
tological Expedition to the Fayum region of Egypt was to re-
cover a larger sample than previously known of the earliest
mammalian microfauna from the continent of Africa, that of
the Fluviomarine formation of the Fayum early Oligocene.
During the course of our investigations the expedition staff
succeeded in locating specimens assignable to two new species
of Primates. In view of the considerable interest in, and rarity
of, Old World Primates dating from this epoch it seems advis-
able to publish a preliminary description of these two forms
without delay, so that they will be available for consideration
by other authors. It is intended that a fuller analysis of their
morphology and relationships will be included in a study of the
Fayum mammalian microfauna now being prepared by the
writer.

ACKNOWLEDGMENT

I wish to express my sincere thanks to Dr. Osman Moharam,
Director of the Department of Geological and Mineralogical!
Research, Ministry of Industry, United Arab Republic; Dr.

2, Postilla Yale Peabody Museum No. 64

Riad Higasy, former Minister of Industry, and Dr. Y. Shawki
Moustafa, Curator of Fossil Vertebrates, Cairo Museum of
Geology, for generously supplying facilities and assistance
which contributed greatly to the success of our expedition to
the Fayum badlands. The field research of which this report 1s
an outgrowth was made possible by a grant in Geology of the
National Science Foundation. Illustrations were prepared by
Margaret EK. Freeman of New Haven and their execution was
partly financed by a grant from the Wenner-Gren Foundation
of New York. The photograph (figure 3) was prepared by
John Howard of the museum staff.

ABBREVIATIONS

A.M.N.H. _.. American Museum of Natural History,
New York.

YCC:P-E: Yale-Cairo, Paleontological Expedition
(field numbers).

Ys PAVic .. Yale Peabody Museum, New Haven.

SYSTEMATICS
Class MamMatia

Order PRIMATES

Suborder ANTHROPOIDEA

Infraorder CATARRHINI

OLIGOPITHECUS,' new genus
Type: Qligopithecus savagei, new species
Generic characters: Lower dental formula 2?. 1. 2. 3., size of mandi-
ble approximately that of the living ceboid primate Leontocebus rosalius,

slightly smaller than its contemporary Propliopithecus haeckeli. Differs
from the latter in having a slightly shallower mandibular ramus, more

‘Named with reference to the Oligocene occurrence of this catarrhine.

August 7, 1962 Two New Primate Species 5)

anteroposteriorly elongated P., distinct paraconid on P,-M,, lower molar
external cingula less distinct and hypoconulid shifted much more lingually
than in Propliopithecus and not distinctly separated from entoconid.
Differs from Parapithecus fraasi in its larger size and in possession of
undoubted, large canine anterior to P,, in absence of metaconid cusp on
P,,—present in Parapithecus, in possession of anteroposteriorly elongated
P., not seen in the latter genus, and in having a much more lingually ex-
tended paraconid ridge on M,-.

c
\

Figure 1. External view of left mandible, Oligopithecus savagei, Type,
Y.C.P.E. 207. x 3 approx.

Discussion: In depth of jaw and canine morphology Oligo-
pithecus much more nearly resembles Propliopithecus than it
does Parapithecus or Apidium, three other primates from the
Fayum early Oligocene. On the other hand, the anteroposteri-
orly elongate P., a feature which typically characterizes post-
Oligocene cercopithecoids and pongids, is not to be seen in any
specimens of these three Fayum genera. Such a lower P, does
occur in a damaged mandible, A.M.N.H. 13389 from the
Fayum, lacking tooth crowns other than on P,, described by
Simons (1961), but in spite of this resemblance P., of A.M.N.H.
13389 is three rooted, a feature of great rarity among Pri-
mates, while that of Oligopithecus is more normal in being two
rooted. Moreover, A.M.N.H. 13389 is, in comparable measure-
ments, over twice larger than the type of Oligopithecus. Pre-
sumably the former specimen belongs to yet another Egyptian
Oligocene primate species, diagnosis of which will have to await
recovery of more satisfactory material; see Simons (1961:3).

4 Postilla Yale Peabody Museum No. 64

The relationship of Oligopithecus to Moeripithecus mark-
grafi, also from the Egyptian early Oligocene, is more obscure,
since comparison of M,. crown patterns in the two forms
fails to reveal any significant similarity. The overall mor-
phology of the tooth series preserved in Oligopithecus appears
to be more like that of certain Kocene prosimians than are these
patterns in other Fayum Primates, except that the P,.. are
lost, the horizontal ramus is deep compared to tooth crown

height, and P, is anteroposteriorly elongate—all similarities to
Old World Anthropoidea. Among Eocene Primates perhaps the
greatest resemblances of Oligopithecus are to Omomyidae,
Anaptomorphidae and Necrolemurinae, which fact agrees well
with the supposition that Anthropoidea are more closely allied
to the so-called tarsioids of Kocene times than they are to other
known Eocene, and earlier, families of the order. The lingual po-
sition of the M,.. hypoconulid in Oligopithecus creates a par-
tial posterior loph parallel to the anterior loph, between meta-
conid and protoconid, which might represent an early stage im
the transition to the bilophodont lower molar pattern of Cer-
copithecoidea. This possibility will require further confirma-
tion before definite assignment of this primate to the latter
superfamily would be advisable. Placement of Oligopithecus
among the Hominoidea is also conceivable but M,-. crown
patterns are so primitive that such an association is equally
dubious. Clearly, however, the creature is not a ceboid or a

prosimian.

OLIGOPITHECUS SAV AGEI

Figures 1 and 4.

Type: Left mandibular ramus, with C-M.,, inclusive, Y.C.P.E. 207.

Horizon and locality: Yale Expedition quarry E, Fossil Wood Zone,
Fluviomarine Formation, early Oligocene age, Fayum Province, Egypt,
about 2.3 miles northeast of American Museum Quarry A (1907) and about

2 Named for Dr. D. E. Savage of Berkeley University who discovered the
type and only specimen.

* By agreement with the Egyptian authorities concerned, types collected on
the Yale 1961-62 expedition will eventually be deposited in the paleontologi-
cal collections of the Cairo Museum of Geology. Pending such assignment
they are here identified by their field numbers.

August 7, 1962 Two New Primate Species 5

eight miles west-northwest of Quasr el Sagha Temple, thirty feet below the
top of the Fossil Wood Zone, see Beadnell (1905).

Specific characters: Not distinguished from generic.

Discussion: The species, O. savagei, is at present known
only from the type individual so that little can be said of varia-
bility in this primate. Although M, is missing in Y.C.P.E. 207
the fact that it had fully erupted is indicated by the preserva-
tion of the anterior root of this tooth in the type. A large wear
facet on the anterior crest descending from P., protoconid indi-
cates that this species must have possessed a sizeable upper
canine which sheared against this facet.

Measurements in millimeters of Oligopithecus savagei are
listed below in comparison with similar measurements on con-
temporary Fayum Primates taken from Kalin (1961).

Mandibular dimensions (Q. savagei).

Anteroposterior

Length of C through M, 19.4
Depth of mandible beneath M. 9.5
Depth of mandible beneath P,, a 10.2

MEASUREMENTS OF TEETH

Oligopithecus Parapithecus Propliopithecus Moeripithecus
savagei fraasi haeckeli markgrafi
left side left side left side right side

Canine
lene thie. 4 3.7 3.2 (Cor P2) 4.0 (right)
wali S68dac 3.3 2.5 (Cor P.) 4.3 (right)
lee
lenoth 22. =-- 4.2 3.3 3.5
Wwacthe es 2r 3.1 2.5 3.8
P,
leno beens 3.3 3.3 3.5
WLC heer 3.0 2.5 4.0
M,
lengthieeee 4.2 a 4.8 5.0
width). =. ..-- 3.4 4.5 4.8
M,
lengthier: 4.2 4.3 4.8 5.4
Width "ee a.5 - 3.5 3.4 4.5 5.4

6 Postilla Yale Peabody Museum No. 64

Genus APIDIUM Osborn, 1908

Type: dA pidium phiomense Osborn, 1908.

Discussion: Although Osborn (1908) was reluctant to state
the ordinal position of this species, it subsequenlty came to be
regarded as a primate, and Gregory (1922) held that it might
be related to the basic cercopithecoid stock or to Oreopithecus;
see Simons (1959: 14). More recently a few authors have again
questioned the primate status of A. phiomense but its resem-
blance to Oreopithecus seems more than convergent, as was
discussed by the writer (1960). Moreover, the discovery of
several isolated upper teeth of a species of this genus, (de-
scribed below) in association in one quarry with several lower
jaws of this form, shows us that similarities to Oreopithecus
in the upper dentition are about equal to those seen in the
lower teeth. Nevertheless, 4 pidiwm species are rather unlike
other known Oligocene Anthropoidea in that the cheek-teeth
are more polycuspidate, the mandibular ramus is shallow, and
the canine may have been small, or alternatively there may
have been three premolars—inadequate preservation of the
new materials rendering this point equivocal. Clearly the stock
of Apidium had differentiated from that of other Fayum Pri-
mates at a considerable remove in time from their common ocur-
rence in the Karly Oligocene of Egypt, but it is in many ways
closest to Parapithecus insofar as the two forms can be com-
pared. The question, therefore, as to the relation of species
of these two genera to the earliest undoubted Old World
Anthropoidea is interrelated. Provisionally the study of Api-
dium suggests that it, together with Parapithecus, may even-
tually be ranked with some certainty among the Anthropoidea.

APIDIUM MOUSTAFAI,* new species
Figures 2, 3.
Type: Left mandibular ramus with P.,-M,, Y.C.P.E. No. 260.

Hypodigm: Type and Y.P.M. numbers 18007, left mandibular rumus
with damaged P,-M,; 18008, unassociated right P*-M*; 18009 right mandi-

bular ramus with P,-M.; 18018 left mandibular ramus with C?-M, ; 18042

*Named in honor of Dr. Y. Shawki Moustafa, whose earnest assistance
and advice were most helpful to our Egyptian expedition.

~
‘

August 7, 1962 Two New Primate Species

left mandibular fragment with P,-M,; 18081, unassociated left P'?, left
M?, left M., left M,, all from Quarry G.

Horizon and locality: Yale Expedition Quarry G, below upper fos-
siliferous zone, Fluviomarine Formation, early Oligocene age, Fayum Pro-
vince, Egypt. One mile due north of American Museum Quarry A and
approximately 100 feet above top of lower Fossil Wood Zone.

Specific diagnosis: About one-eighth smaller than 4. phiomense, with
slighter development of lateral basal cingula and fewer accessory cuspules
on P, heel and on M,—.,, and as a whole, comparatively smaller and more
primitive than in 4. phiomense, with posterointernal angle of M, produced
more lingually.

Figure 2. A. Crown view and B. External view, 4 pidium moustafai
Type, Y¥.C:P.E. 260. x 5 approx.

Discussion: This species is both smaller and earlier occur-
ring than the type of A. phiomense. That a significant lapse of
time exists between the populations from which the two species
are derived seems probable in view of studies of other faunal
elements from the upper part of the Egyptian Fluviomarine
Formation now in progress. Although the exact locality of the
type of A. phiomense is not known, it was reported by Osborn
(1908) as having been discovered upon the upper fossiliferous

8 Postilla Yale Peabody Museuni No. 64

level, which begins about 100 feet stratigraphically above the
horizon of Quarry G. If the practice of some past students of
fossil Primates were followed here, a case for generic separa-
tion of these two species could probably be made, but this type
of splitting should not be attempted until these forms are much

better known.

MeraAsvuREMENTS IN MILLIMETERS OF Apidium moustafat

YPM. “YPM. | TYPE:
180158 18009 Y.C.P.E. 260
CDG or Es
Lemip:bhy (35 vane. c cere couseeters 2.5
Pv Gin i ke cen se=usk oscars Si: 2.0
| Pe
lengthy eeacee ssomm eat: 2.7 2.7 2.8
width ean thee, Seco htestis 2.0 1.9 2.0
P,
lemothi pss cies yer 2.7 2.7 2.8
Width sg. oe. scouts 2.3 2.2 2.3
M,
Leno; theese era 3.5 3.6 3.7
Wildithh is g7se scien ae 2.8 2.7 3.0
M.
Lengthy. ee creo sees 3.6 3.6
width 284s ora ke fe ieee 3.2 3.1
M,
NSM 2 egos pen Homn s 3.6 4.0
V0(6 U8 ler eaerene mesa Hoes 3.0 2.9
Depth of mandible beneath
Mie Bye eice ck seas eeats aes 6.0 tel 6.8
Anteroposterior length
ORIN Eg ie Se in AG ete at 15.3 16.8

| Ease Le ree eeema er coer S50 8.6 9.0 8.8

August 7, 1962 Two New Primate Species 9

CONCLUSIONS

Recent collections of Primates from the Fayum early Olig-
ocene deposits of Africa indicate the existence of at least two
new forms of Primates. Study of the first of these, Oligo pithe-
cus savagei, suggests that it is assignable to the Anthropoide:
and that it may represent an early stage in the differentiation
of Cercopithecoidea. Near agreement in expected size, and ap-
proximation in horizon and locality suggests that a catarrhine
frontal bone described by Simons (1959) may provisionally be
referred to this species. Placement of this frontal with A pidium
or Parapithecus, which are also of suitable size, seems less ap-
propriate in view of non-anthropoidean features such as are to
be seen in their anterior dentitions. Known Propliopithecus and
Moeripithecus are probably too large to have had a frontal this
size, but of course this skull fragment could well belong to a
species otherwise unkown. A second species, A pidium mousta-
fai, here described, appears to represent an earlier and ances-
tral population to Apidium phiomense which was recovered
from the upper part of the Fluviomarine Formation. Newly
discovered upper teeth of Apidium strengthen the view that
species of this genus, together with Oreopithecus bamboli, rep-
resent a fourth major group of Old World Higher Primates

distinct from cercopithecoids, pongids and hominids.

10 Postilla Yale Peabody Museum No. 64

Figure 3. Right mandibular ramus of Apidium moustafai, Y.P.M.
18009. x 6 approx.

August 7, 1962 Two New Primate Species ila

Figure 4. Crown view of dentition, Oligopithecus savagei, Type,
Y.C.P.E. 207. x 6 approx.

12 Postilla Yale Peabody Museum No. 64

REFFRENCES

Beadnell, H. J. L., 1905. The topology and geology of the Fayum provence
of Egypt. Publ. Sury. Dept., Ministry Public Works, Egypt, p. 1-101,
10 fig., 24 pl.

Gregory, W. K., 1922. The origin and evolution of the human dentition.
Baltimore, Williams and Wilkins Co., p. 1-548.

Kahlin, J., 1961. Sur les primates de VOligocéne inférieur d’ Egypte. Annales
de Paléontoiogie, tome 47, p. 1-48, 18 fig., 7 pl.
Osborn, H. F. 1908. New fossil mammals from the Fayum Oligocene,
Egypt. Bull. Amer. Mus. Nat. Hist. v. 24, art. 16, p. 265-272 6 fig.
Simons, EK. L., 1959. An anthropoid frontal bone from the Fayum Oligocene
of Egypt: the oldest skull fragment of a higher primate. Amer. Mus.
Nov., no. 1976, p. 1-16, 4 fig.

——_———.,, 1960. Apidium and Oreopithecus. Nature. v. 186, no. 4727, p.
824-826, 1 fig.

——————, 1961. An anthropoid mandible from the Oligocene Fayum
beds of Egypt. Amer. Mus. Nov. no. 2051, p. 1-5, 1 fig.

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