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Oligocene primates from the Fayum, Egypt, show remarkable diversity. Twelve primates of five different taxonomic families have been described. Until recently, antecedents to these primates were unknown (1). Finds made in Egypt since 1987 of a second and different series of anthropoids from Eocene deposits give evidence about the roots of the anthropoid family tree. This second set of early higher primates comes from a site, locality 41 (L-41), situated north of Lake or "Birket" Qarun in the Jebel Qatrani Formation, Fayum Province, Egypt, which is dated at about 36 million years ago. The L-41 primates belong to seven different genera and species, one of which is undescribed (2-4). This brings the total of known Fayum primate species to 19. These Eocene species could belong to six or more families. In this report, I use dental and cranial features (2-4) to determine if Catopithecus and its contemporaries are definitely early anthropoids, and if they are, are they related to any earlier group at the base of our own branch of the primate family tree?
In 1992 and 1993, nearly complete specimens of Catogithecus were found at L-41 that together hold the entire antemolar dentition. A mandible of another contemporary L-41 primate, Arsinoea, also has incisors preserved. Shape and proportions in the antemolar teeth have been the subject of considerable study in hopes of identifying what Eocene primate group is related to the ancestry of apes and monkeys. Thus, unlike other specimens of Anthropoidea dating before the Miocene Epoch, Catopithecus finds preserve all the anterior teeth and most details of skull structure. Although the Oligocene genera Aidium and Aegytopithecus from the Fayum are known from scores of specimens, none preserve associated upper incisors. Hence, even in these well-known primates, the most anterior upper dental arcade has been reconstructed from isolated teeth. Tne Catopithecus crania show the locale of the foramen magnum, the position of various other foramina (including the lachrymal, carotid, and postglenoid foramina), and the extent of postorbital plates and also make possible determination of the probable brain volume, 3.1 cm sup 3 .
Some of the mandibles and cranial parts of Catoithecus discussed here include a partial skull at the Duke Primate Center (DPC 8701), a nearly complete but shattered skull housed at the...