Pruning the family tree

A spate of new species added to an already crowded human family has caused our once elegant evolutionary tree to look more like a gangly bush. But, in February 21 Science, Robert Blumenschine and colleagues at the Department of Anthropology, Rutgers University, New Jersey, US, describe a new find from Olduvai Gorge in Tanzania that could simplify the number of species present at the origin of our genus, Homo (Science, 299:1217-1221, February 21, 2003).

Almost 40 years ago Louis Leakey and his colleagues described a series of fossils from Olduvai Gorge as the oldest member of our genus. Because of its large brain size, almost 700ml, and associated stone tools, the find was dubbed Homo habilis, literally "handy man". Nearly a decade later Leakey's son Richard discovered a more complete skull in northern Kenya, expanding the reach of Homo habilis across much of the Rift...