AN INTERNATIONAL team of scientists led by University of the Witwatersrand palaeoanthropologist Lee Berger yesterday announced the discovery of several 2-million- year-old partial skeletons of a new species of hominid in the Cradle of Humankind near Johannesburg, sparking a fresh debate about who our immediate ancestors were.
Writing in this week's edition of the US journal Science, Berger describes two members of the new species, which he has called Australopithecus sediba, and controversially suggests that they may have been a transitional creature between Au. africanus and the early members of our genus Homo.
Sediba means "well- spring" in Sotho.
"We have never seen an early hominid species that looks like this," said Berger .
He has long argued that Au. africanus - to which the famous Mrs Ples and Taung Child fossils belong - is not the evolutionary dead end that many of his peers think. His claim that Au. sediba sprang from Au. africanus and
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that it could be the immediate ancestor to our genus Homo has already sparked debate among the world's top palaeoanthropologists, who have views of their own. Donald Johanson, discoverer of the famous 3,2-million-year-old hominid fossil Lucy, said it was more likely Au. sediba descended from the earliest Homo species in east Africa - which may have been the tool-making Homo habilis - and then migrated back to southern Africa.
Berger's team found a male aged between 11 and 13 and an adult female, lying close together in what was once a deep cave. Remains of at least 25 animal species were also found, including sabre-toothed cats, antelope, a wild dog, a hyena, mongooses, and others not seen before. Two more skeletons have been found since Berger sent his research to Science last year, making this perhaps SA's richest fossil haul yet.
The fossils are unusually well preserved, perhaps because they fell to their death in the cave and were safe from scavengers, said Berger's collaborator, Paul Dirks from James Cook University.
Au. sediba had the small brain and the orangutan-like arms of australopithecines, and the short, powerful hands and smaller teeth of a modern human. It stood about 1,3m high and would have been comfortable climbing trees and walking much like us, he said.