MORPHOLOGY: Aegyptopithecus zeuxis had a dental formula of 2:1:2:3 on both the upper and lower jaws (Fleagle, 1988). The lower molars increase in size posteriorly (Fleagle, 1988). The molars showed an adaptation called compartmentalizing shear, which is where "the cutting edges involved in the buccal phase serve to surround basins in such a way that food is cut into fragments that are trapped and then ground during the lingual phase" (Martin, 1990). The canines of this species were sexually dimorphic (Fleagle, 1988). The ascending mandibular ramus of this species is relatively broad (Conroy, 1990). The orbits are relatively small suggesting that this was a diurnal species (Fleagle, 1988). This species had dorsally oriented orbits and also had postorbital constriction (Conroy, 1990). The interorbital distance of this species is large much like that found in colobines (Conroy, 1990). A sagittal crest develops in older individuals that extends over the brow ridges (Fleagle, 1988). This species has an auditory region which is similar to that found in platyrrhines, having no bony tube and the tympanic fused to the lateral surface of the bulla (Fleagle, 1988). This species had a relatively small brain compared to other haplorrhines (Fleagle, 1988); the cranial capacity was about 30 cc (Conroy, 1990). Although the brain is advanced as compared to strepsirhines in having an expanded visual cortex, comparatively small olfactory bulbs, and a central sulcus (Conroy, 1990). The humerus has a head which faces posteriorly and is narrower than primates which practice suspensory behavior (Conroy, 1990). The humerus also shares some features with extant hominoids: large medial epicondyle and a comparatively wide trochlea (Conroy, 1990). This species has an ulna that compares to the extant genus Alouatta (Conroy, 1990). On the foot bones, this species had a grasping hallux (Fleagle, 1988). Aegyptopithecus zeuxis had an average body mass of around 6.7 kilograms (Fleagle, 1988). This species shares characteristics with haplorhines such as: fused mandibular and frontal symphyses, postorbital closure, and superior and inferior transverse tori (Kay et al., 1981; Fleagle and Kay, 1983; cited in Conroy, 1990).
RANGE: Aegyptopitheucs zeuxis was found in Africa and discovered in the country of Egypt (Fleagle, 1988). This species occurred during the early Oligocene (Fleagle, 1988).
Based upon dental morphology this was a frugivorous species in which leaves were also an important part of the diet (Fleagle, 1988).
Based upon postcranial remains this species was most likely an arboreal quadruped (Fleagle, 1988). The first metatarsal and the morphology of the talus suggest an arboreal quadruped (Conroy, 1990).
Conroy, G.C. 1990. Primate Evolution. W.W. Norton and Co.: New York.
Fleagle, J.G. 1988. Primate Adaptation and Evolution. Academic Press: New York.
Fleagle, J.G. and Kay, R. 1983. New Interpretations of the Phyletic Position of Oligocene Hominoids. In New Interpretations of Ape and Human Ancestory. Eds. R. Ciochon and R. Corruccini. Plenum: New York.
Kay, R., Fleagle, J.G., and Simons, E. 1981. A Revision of the Oligocene Apes of the Fayum Province, Egypt. American Journal of Physical Anthropology, Vol. 55, 293-322.
Martin, R.D. 1990. Primate Origins and Evolution: A Phylogenetic Reconstruction. Princeton University Press: Princeton, New Jersey.