San Diego Museum of Man - Footsteps Through Time

Timestone 2
34 to 31 million years ago
Aegyptopithecus zeuxis

This species is one of the best known ancient primates from what is now Africa and Asia. It had characteristics of both apes and monkeys and lived when primates were evolving rapidly.

The Earth's climate was cooling, but a swampy, tropical rainforest grew near what is now the Fayum in Egypt. A variety of primates lived there, including the cat-sized Aegyptopithecus. Skeletons suggest that this species lived in trees and ate fruits and leaves. Scientists believe it was an ancestor to Asian and African monkeys and apes.

Aegyptopithecus zeuxis
Found in the Fayum, Egypt, in 1965 by Elwyn Simons
Age: around 33 million years

Old World and New World Monkeys

Differences show separate paths
Old World monkeys live in Africa and Asia. New World monkeys live in Central and South America. The two groups once shared a common ancestor, but today are different in many ways, including their tails, nostrils, and teeth. These differences reflect the evolutionary path each group followed since they separated from a common ancestor between 34 and 25 million years ago.

Rafting to new worlds
Some fossils of New World monkeys are 30 million years old and come from South America. The fossils suggest the monkeys were from African stock, but no one knows how they crossed the ocean. The main theory is that they rafted there after being swept to sea accidentally on masses of plant material. The two continents were closer together then and ancient islands may have acted as stepping stones.

Earth's warming trend was over

Thirty-four million years ago, Earth's climate was cooling and becoming more seasonal. Tropical forests receded toward the equator, and temperate mixed forests of evergreen and deciduous trees replaced them at higher latitudes. With disappearing habitats, primates gradually vanished from North America and Europe. They thrived in tropical Africa and Asia.