5.2 million year old human teeth

Six fossil teeth found in Ethiopia and believed to be about 5.2 million years old may be from a previously unknown type of prehuman primate that was among the first to evolve from the common ancestor of humans and apes, a study suggests.

The teeth have distinctive features that are thought to have existed among the first hominids to emerge after the ape and human lineages evolved apart some 6 million to 8 million years ago, researchers say in the journal Science on Thursday, reports &to=http://www.freep.com' target=_blank>Freep.com

Scientists from Berkeley, Cleveland and Japan may have finally identified the first complete species of hominids, or human ancestors, that emerged almost 6 million years ago, after the evolutionary split that led to today's chimps and humans.

Key clues to its existence are six fossil teeth found in the Ethiopian desert that have forced researchers to reclassify a type of hominid previously regarded as a "subspecies," they announced in today's issue of Science. Ardipithecus kadabba is the new species' name.

Besides being a separate species, Ardipithecus kadabba also may have been the first big step on the long evolutionary road from the African jungle to modern humans, inform &to=http://www.sfgate.com' target=_blank>SFGate.com