Anthropoid origins

The origin of anthropoid primates (monkeys, apes, humans) is one of the most controversial issues in paleoanthropology. Living anthropoids are united by several morphological features, the most important of which is that the eye sits in a fully closed bony socket, reflecting a key shared innovation of the group—that is, an emphasis on vision over olfaction. Molecular analyses support an origin of anthropoids in Asia, but fossil evidence indicates that Africa is the place where morphologically recognizable anthropoids began their initial diversification. Part of the controversy comes from the use of two competing definitions of Anthropoidea, “crown” versus “stem.” Two different scenarios of anthropoid origins are explored: (1) a deep time African origin, which is consistent with a crown definition; and (2) a Middle Eocene Asian origin, which is consistent with a stem definition. At present there is little consensus about the timing and place of anthropoid origins.