Evolution and environment in the Hominoidea.

Between 10 and 20 million years ago, a variety of hominoid primates lived in Africa, Europe and Asia. The question of which of these, if any, lie closest to the ancestries of humans and modern apes remains a lively source of debate. Recent fossil discoveries, though, shed light on the environments in which the various groups of hominoid emerged and, it is hoped, on their evolution. But the lack of a hominid fossil record before about 5 million years ago--and any fossil record for the African apes--is still a frustrating barrier.