Eocene Epoch

55-34 million years ago


The first anthropoid primates were the ancestors of New World monkeys, Old World monkeys, apes, and humans.

The earliest group of anthropoid primates are the Oligopithecines known from the Late Eocene which include Oligopithecus savagei, Catopithecus browni, and Proteopithecus sylviae. Fossils of teeth are similar to those primates which feed on insects and fruit. The large separation between the orbits (the interorbital distance) is similar to that of prosimians which rely more on their sense of smell than the smaller distance observed in all other anthropoids. Although the braincase of Catopithecus was crushed, it appears that its brain size tobody size ratio was smaller than modern anthropoids (Rasmussen, 1992). The incomplete fossil of Algeripithecus suggests that simians existed in North Africa by the early to mid Eocene and the eleven known simian genera of the Fayum deposit in Egypt (including Catopithecus ) date from the boundary between the Eocene and Oligocene. One of the Fayum simians, Plesiopithecus, may have lacked incisors in the lower jaw (Martin, 1993).