Australopithecus

Australopithecus afarensis and Australopithecus africanus are among the most famous of the extinct hominids. A. africanus used to be regarded as ancestral to the genus Homo. However, fossils assigned to the genus Homo have been found that are older than A. africanus. Thus, the genus Homo either split off from the genus Australopithecus at an earlier date, or both developed from a yet possibly unknown common ancestor independently. The brains of most species of Australopithecus were roughly 35% of the size of that of a modern human brain.