The new fossils of Ardipithecus ramidus — known as 'Ardi' — offer the first substantial view of the biology of a species close to the time of the last common ancestor, estimated to be at least 6 million years ago. Like modern humans, Ardi could walk upright and didn't use her arms for walking, as chimps do. Still, she retains a primitive big toe that could grasp a tree like an ape.
"This spectacular specimen shows why fossils really matter," says Andrew Hill, head of anthropology at Yale University in New Haven, Connecticut.
Previously, the oldest near-complete skeleton of a human ancestor was the 3.2-million-year-old Australopithecus afarensis skeleton known as Lucy, also from Ethiopia. Because Lucy had many traits in common with modern humans, she didn't provide much of a picture of the earlier lineage between apes and humans, says Alan Walker, a biological anthropologist at Pennsylvania State University in University Park. The new A. ramidus does.
Friday, October 02, 2009
The fascinating find of the oldest hominid skeleton so far prompts a new evaluation of human evolution: