Aegyptopithecus cranium
Aegyptopithecus cranium
Image: Duke University

Artist's reconstruction
Image: E. M. McCarthy

Fayum oasis Fayum today is an oasis region with a large saltwater (but formerly freshwater) lake fed by a channel from the Nile. In past ages the Fayum alternated between woodland and open grassland, depending on the varying levels of rainfall and changes in the drainage patterns of the Nile. Image: Wikimedia (Zorbey Tunçer)

Aegyptopithecus (/ee-JIP-tō-PITH-ə-kəs/), meaning Egyptian ape or monkey, was an Oligocene primate, the remains of which were discovered in 1965 by paleontologist Elwyn L. Simons in the Fayum Formation of northwestern Egypt. Today, Fayum has a desert climate, but 34 million years ago during the Oligocene, it was a region of swampy forest.

This early primate is widely believed to be ancestral to monkeys (cercopithecoides), as well as to humans and apes (hominoids). In size and structure the creature was like a rather small modern-day monkey. It had a body weight of about 6 kg (13 lbs). The brain, though, was smaller than that of any living monkey.

Five partial lower jaws, and a nearly complete skull, all dating to about 34 million years ago, have been found (other specimens, described under the name Propliopithecus may represent the same animal). The teeth are low crowned, with relatively little enamel, which suggests that this cat-sized creature ate a diet of mostly soft fruits. The face is strongly prognathic, that is, the jaws protruded well beyond the plane formed by the upper face to form a prominent snout (see photo above). crest.

The dental formula was the same as that of a human (two incisors, one canine, two premolars and three molars per ramus). But the molars were generally more similar to those of an Old World monkey (i.e., to the members of Family Cercopithecidae) than to an ape's or a human being's.

These creatures seem to have made their abode in the forest canopy and, indeed, their low-crowned teeth with relatively little enamel suggest a folivorous and/or frugivorous diet. Individual specimens show an apparent sexual dimorphism, with males larger and having bigger canines. A sagittal crest is present in both sexes, but is more prominent in males.

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Simons, E.L. 1967. The earliest apes. Scientific American, 217(6):28-35.

Simons, E.L. 1987. New faces of Aegyptopithecus from the Oligocene of Egypt. Journal of Human Evolution, 16:273-289.

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