Washington  - Anthropologists in Ethiopia have conducted the most complete analysis yet of one of the earliest known hominids, challenging many of the assumptions about how humans and apes evolved.

More than 110 specimens of the 4.4-million-year-old species, Ardipithecus ramidus, were uncovered, according to a series of articles to be published in the US journal Science on Friday. They included a partial female skeleton nicknamed Ardi, who is more than a million years older than the famous Lucy skelton uncovered in the 1970s.

The findings provide scientists with information on what a common ancestor for humans and apes may have been like, with a mix of traits from earlier species and later species. But Ardi and her species were less like modern apes than scientists expected.

Ardipithecus ramidus lived in a wooded environment, climbing on all fours in the trees and walking on two feet on the ground, not walking on their knuckles like gorillas or swinging from the trees like chimps.

"So when you go from head to toe, you're seeing a mosaic creature, that is neither chimpanzee, nor is it human. It is Ardipithecus," Tim White of the University of California Berkeley, who is one of the lead authors of the research, said.

The species indicates that apes likely evolved extensively after scientists say the apes and humans diverged. This challenges the long-standing scientific belief that apes give a good look at what an early ancestor of humans may have looked like.

"Darwin said we have to be really careful. The only way were really going to know what this last common ancestor looked like is to go and find it. Well, at 4.4 million years ago we found something pretty close to it. And, just like Darwin appreciated, evolution of the ape lineages and the human lineage has been going on independently since the time those lines split, since that last common ancestor we shared," White said.  dpa