First anthropoid primates

Anthropoids are the primate group that includes monkeys, apes and humans. They differ from lemurs and other early primates in having eyes that sit side by side with a bony wall behind each socket, fused halves of the lower jaw, larger brains and, in most cases, daytime activity. Their oldest known fossils include Eosimias, 'dawn monkey', discovered in 1994 by Christopher Beard and colleagues in deposits about 45 million years old at Shanghuang in Jiangsu, China. Eosimias was tiny, weighing about 100 grams, and is known mostly from jaws and teeth.

Where anthropoids first arose is debated. Contemporary fossils from North Africa, such as Biretia and Afrotarsius, are also candidates, and some scientists favor an Asian origin while others favor Africa. By about 40 million years ago, anthropoids were clearly established in North Africa and in Asia. They began as small fruit and insect eaters living in warm, wet forests during a greenhouse period of high temperatures. From these early forms came two branches: the platyrrhines, or New World monkeys, and the catarrhines, which include Old World monkeys, apes and humans.