Friday, April 23, 1999 Published at 16:16 GMT 17:16 UK
Fossil find may be 'missing link'
Stone tools left scratch marks on animal bones
Skull and tooth fragments unearthed in Ethiopia may be those of a completely new hominid - or human-like species - that lived 2.5 million years ago.
This is a contentious claim among scientists who have competing theories as to how humans first emerged in history.
If these can all be shown to have come from the same creatures - which has not been achieved yet - then a vital missing link in the evolution of humans from apes may well have been found.
The new discovery may sit between the two in time and evolution.
Whatever the connection between the various finds at Bouri, the tools are the earliest examples ever found of technology being used to eat meat and scrape marrow out of bones.
"What we found was a cranium on a hillside, two and a half million years old, having a small brain case, a very projecting face, and very large, back teeth," says Professor Tim White from the University of California-Berkeley who co-led the team with Berhane Asfaw of Ethiopia's Rift Valley Research Service.
The difficulty is establishing the significance of A. garhi in terms of human evolution.
"You go into this period with, in essence, bipedal, big-toothed chimps, and come out with meat-eating large brained hominids," says Professor White. "That's a big change in a relatively short time."
Many paleoanthropologists will need more evidence to be convinced. For a start, the Bouri limb bones may not necessary be those of A ghari.
The research is published in two separate papers in the journal Science.