Anthropoid humeri from the late Eocene of Egypt

A number of recent studies have, by necessity, placed a great deal of empha sis on the dental evidence for Paleogene anthropoid interrelationships, but cladistic analyses of these data have led to the erection of phylogenetic hypotheses that appear to be at odds with biogeographic and stratigraphic c onsiderations. Additional morphological data from the cranium and postcrani um of certain poorly understood Paleogene primates are clearly needed to he lp test whether such hypotheses are tenable. Here we describe humeri attrib utable to Proteopithecus sylviae and Catopithecus browni, two anthropoids f rom late Eocene sediments of the Fayum Depression in Egypt. Qualitative and morphometric analyses of these elements indicate that humeri of the oligop ithecine Catopithecus are more similar to early Oligocene propliopithecines than they are to any other Paleogene anthropoid taxon. and that Proteopith ecus exhibits humeral similarities to parapithecids that may be symplesiomo rphies of extant (or "crown") Anthropoidea, The humeral morphology of Catop ithecus is consistent with certain narrowly distributed dental apomorphies- such as the loss of the upper and lower second premolar and the development of a honing blade for the upper canine on the lower third premolar-which s uggest that oligopithecines constitute the sister group of a clade containi ng propliopithecines and Miocene-Recent catarrhines and are not most closel y related to Proteopithecus as has recently been proposed.