The cranium of Parapithecus grangeri, an Egyptian Oligocene anthropoidean primate

A nearly complete skull of Parapithecus grangeri from the early Oligocene o f Egypt is described. The specimen is relatively undistorted and is undoubt edly the most complete higher primate skull yet found in the African Oligoc ene, which also makes it the most complete Oligocene primate cranium worldw ide. Belonging in superfamily Parapithecoidea, a group regarded by some as the sister group to all other Anthropoidea, this skull reveals important in formation about the radiation of stem anthropoideans. This cranium is about 15% larger than size estimates based on a fragmentary cranium of its conte mporary and close relative Apidium phiomense. It is about the same size as that of the gray gentle lemur, Hapalemur griseus, or of platyrrhines such a s the owl mon key, Aotus trivirgatus, or the titi mon key, Callicebus torqu atus, Comparatively small orbits and size differences in jaws and teeth sho w it was both diurnal and dimorphic. This is the only specimen of the speci es that shows (from sockets) that there were four small upper incisors. Sev eral mandibular specimens of the species establish that there were no perma nent lower incisors and that the symphysis was fused. Like other early anth ropoideans this species possessed a lower encephalization quotient and less -developed orbital frontality than later anthropoideans, There is full post orbital closure and fusion of the metopic suture, and the ectotympanic form s a rim to the auditory aperture. A probable frontal/alisphenoid contact is a potentially derived resemblance to Catarrhini. A proposed separate genus for the species P, grangeri is not sustained.