Ptolemaiida, a New Order of Mammalia-With Description of the Cranium of Ptolemaia Grangeri
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Proc. Natl. Acad. Sci. USA Vol. 92, pp. 3269-3273, April 1995 Evolution Ptolemaiida, a new order of Mammalia-with description of the cranium of Ptolemaia grangeri ELWYN L. SIMONS* AND THOMAS M. BOWNt *Duke University Primate Center, Durham, NC 27705; and tU.S. Geological Survey, Paleontology and Stratigraphy Branch, Denver, CO 80225 Contributed by Elwyn L. Simons, November 23, 1994 ABSTRACT All records of the exotic mammalian family assigned these specimens to a new genus and species, Qa- Ptolemaiidae are known from 182 m of section in the lower to runavus meyeri. A specimen located on the desert surface north middle parts of the upper Eocene and lower Oligocene Jebel of quarry A in 1961 also belongs to Osborn's type species, P. Qatrani Formation, Fayum Depression, Egypt. Previous ten- lyonsi. tative assignments of ptolemaiid affinity have suggested that In 1978, after heavy rain eroded deeply into Fayum badland these animals are allied with the primitive suborder Panto- channels, fossil bones were exposed at what became vertebrate lesta (currently placed in the order Cimolesta). Though fossil quarry V, at the 166-n level of the Jebel Qatrani perhaps ultimately derived from an unknown member of that Formation. Since then, collecting at quarry V has yielded all group, the likelihood that ptolemaiids constitute a distinct other specimens of ptolemaiids (the new species Ptolemaia group is considered, and analysis of all known materials of grangeri and the new genus and species Cleopatrodon ayeshae), Ptolemaia, Qarunavus, and Cleopatrodon demonstrates that except for a single mandible and two isolated teeth from quarry these genera belong in their own order, the Ptolemaiida, I (244-m level). The quarry I specimens were placed in the new described here. The morphologically unique dentition and species Cleopatrodon robusta (4). The very restricted distribu- only known ptolemaiid cranium, that ofPtolemaia grangeri, is tion, even for Fayum sites and faunas, hints that ptolemaiids described. Although Qarunavus and Ckopatrodon show some must have had a lifestyle that significantly constrained their similarities in primitive characters to European merialine paleoenvironmental distribution, an inference bolstered by Paroxyclaenidae (suborder Pantolesta), their affinities clearly their highly aberrant dental morphology. The Ptolemaiida are lie with Ptolemaia and the Ptolemaiida. presently known from 48 specimens that record three genera and five species. No certain record of the group exists else- Paleontolo'gical expeditions to the lower Tertiary badlands of where. the Fayum Depression of Egypt under the direction of the senior author have greatly expanded knowledge of Paleogene SYSTEMATIC PALEONTOLOGY North African mammals. At present, 19 families are recog- nized. These families fall into two groups-one of which had Ptolemaiida, New Order. its origin outside Africa, and the other, a smaller and perhaps more intriguing set, had an apparent African endemic origin. Holotype. Ptolemaia lyonsi Osborn, 1908. Diagnosis. Among Among the latter groups are at least some of the various all mammals, the Ptolemaiida most closely resemble the Me- families of early primates, the macroscelidid and tenrecoid rialinae (Cimolesta, Pantolesta, Paroxyclaenidae) of the Eo- insectivores, the proboscideans, the arsinoitheres, and, possi- cene of England and France. From merialines (and therefore bly, members of the aquatic order Sirenia. With these also from Pantolesta and Order Cimolesta and all other orders of belongs the group that forms the subject of this contribution, mammals), the Ptolemaiida differ in the unique combination the new order Ptolemaiida. of the following characters: (i) dental formula = I3/?3, Cl/i, The Ptolemaiida is one of the most restricted of mammalian P2-4/2-4, M3/3 where I, C, P, and M refer to numbered orders known in terms of both its temporal and its geographic upper incisor, canine, premolar, and molar teeth (i, c, p, and distribution. It is confined to an occurrence in or near three m = lower); (ii) incisors small and slightly procumbent; (iii) fossil vertebrate quarries between the 62- and 244-m levels (1) upper canine tall, straight, and piercing, with striated enamel; of the Jebel Qatrani Formation, and fossils of Ptolemaiida (iv) lower canine short and broadly curved; (v) premolars have been found only in a small area of about 3.0 x 1.5 km in bunodont, high-crowned, and increasing in size posteriorly, the Fayum Depression of Egypt. No postcranial bones have greatly hypertrophied in Ptolemaia; (vi) P2/2-P3/3 elongate; been positively identified to date, and all known specimens (vii) P4/4 semimolariform or molariform with at least hypo- total only eight mandibles, two maxillary fragments, a skull conid and either metaconid or lingually expanded protoconid fragment bearing the frontal bones, one skull, and 36 isolated (p4 of P. grangeri possesses all principal trigonid and talonid teeth. cusps); (viii) molars bunodont, somewhat high-crowned to The oldest known members of this order come from in or greatly hypertrophied and decreasing in size from Mi/i to near quarry A in the lower sequence of the Jebel Qatrani M3/3 (excepting M3/3 of Cleopatrodon; M3/3 is unknown in Formation, a site actively worked by the American Museum of Qarunavus); (ix) lower molar trigonids greatly compressed Natural History expedition of 1907. There, the first ptolemaiid anteroposteriorly with large lingual paraconids closely ap- specimen, the type ofPtolemaia lyonsi, was collected, and it was pressed to metaconids; (x) lower molar talonids with ento- later described by Osborn (2). Early collectors also secured conids weak or absent and talonid notch open; (xi) premolars from quarry A right and left juvenile mandibles of a somewhat and molars lacking stylar shelves and lacking lingual and labial larger ptolemaiid. These specimens became part of the col- cingulae; and (xii) lower molars vespiform in occlusal view, lections of the British Museum of Natural History and the with pronounced internal constriction at the hypoflexid and Stuttgart Natural History Museum. Simons and Gingerich (3) talonid notch. The publication costs of this article were defrayed in part by page charge Abbreviations: CGM, Cairo Geological Museum; DPC, Duke Uni- payment. This article must therefore be hereby marked "advertisement" in versity Primate Center; I/C/P/M and i/c/p/m, numbered incisor/ accordance with 18 U.S.C. §1734 solely to indicate this fact. canine/premolar/molar upper and lower teeth respectively. 3269 Downloaded by guest on September 23, 2021 3270 Evolution: Simons and Bown Proc. Natl. Acad Sci. USA 92 (1995) new skull (DPC 10684, Figs. 3 and 4), the composite dentition, 14 and an edentulous lower jaw (DPC 5434) show that P2-4 and A p2-4 increase in size posteriorly, whereas P4-M3 and p4-m3 B decrease in size posteriorly. P4, p4, and M1-3/1-3 have greatly hypertrophied crowns, equal to or exceeding that in the type ofthe genus,P. lyonsi. The dental formula ofP. grangeri is 13/?, Cl/i, P3/3, M3/3. I2 is a tiny, pointed tooth with a broad crest arising from the base of the enamel on the internal side to a point just posterior c I 1 to the tip of the crown. The tooth exhibits minor posteroin- UII, ternal wear from the tip of the crown to just above the crown The and FIG. 1. Upper teeth of Ptolemaiida. (A) Right P3 (DPC 6281) and base. alveoli of left 11-3 right Ii and 13 show that the right P4 (DPC 6500) of C. ayeshae. (B) Composite M1-3 ofP. grangeri, incisors were slightly procumbent. I1 is slightly the largest shown as a left dentition; right Ml = DPC 10408 (reversed), left M2 incisor, and 12 and I3 are of about equal size. I3 is separated = DPC 3229, and left M3 = DPC 10298. (C) Right m3 (reversed) of from the immense canines by a narrow but deep fossa for P. grangeri in labial (Left) and occlusal (Right) views. (Bar = 10 mm.) housing the lower canines. The upper canines (C1/1) possess vertically striated enamel, Included taxa. The type genus; Qarunavus Simons and and a cross-section of the tooth at the base of the enamel is Gingerich, 1974; Cleopatrodon Bown and Simons, 1987. elliptical but with a strong crest at (at least) the posterior axis Distribution. Fayum Depression, Egypt; 62- to 244-m levels of the ellipse. The canines are very tall, vertically implanted, of Jebel Qatrani Formation (upper Eocene-lower Oligocene). and uncurved (straight and piercing). Minor wear on the P. grangeri Bown and Simons, 1987. Holotype. CGM (Cairo canine tips has just penetrated the enamel; however, on the Geological Museum, Egypt) 42843, left m3 [see Fig. 2; also see anterior face of the crown, strong wear produced by the lower figure 1E of Bown and Simons (4)]. canine has obliterated the enamel and penetrated into Hypodigm. The type specimen and DPC (Duke Primate deeply Center) 695, left ml (see Fig. 2); DPC 2062, frontal bones of the dentine. This wear is even and flat, extends from the tip of skull; DPC 2320, left p4; DPC 2666, left p2; DPC 3229, left M2 the crown dorsad to at least 7 mm above the enamel line in the (Fig. 1B); DPC 3994, right M2 [see Fig. 4C of Bown and right canine, and reaches to near the tip of the left canine and Simons (4)-formerly assigned to C. ayeshae]; DPC 5434, left at least 3.6 mm above the base of the enamel in that tooth. edentulous ramus with alveoli for c and p2-m3 [see Fig. 1C of Alveoli show that P2 had two about equisized roots that were Bown and Simons (4)]; DPC 5458, right p3 (Fig. 2-formerly aligned anteroposteriorly. The anterior alveolus is displaced believed to be p4); DPC 7293, M3 of indeterminate side; DPC somewhat by labial crushing on the right side.