By Julie Steenhuysen
Reuters

CHICAGO (Reuters) - An ancient skull and upper jawbone from two early branches of the human family tree — Homo erectus and Homo habilis — suggest the early human ancestors may have lived close together for half a million years, researchers said on Wednesday.

The fossils, discovered in eastern Africa, challenge the understanding that humans evolved one after another like a line of dominoes, from ancient Homo habilis to Homo erectus and eventually to Homo sapiens, or modern people.

“There has been a view that has suggested habilis very slowly evolved into erectus,” said Susan Anton, a professor of anthropology at New York University. “Now we have the two cohabitating, so that can no longer be the case.”

The research, published in the journal Nature, was conducted by nine scientists including Anton, paleontologist Meave Leakey and her daughter Louise Leakey, both explorers in residence at the National Geographic Society, and Fred Spoor of University College London.

Both fossils were found in 2000 east of Lake Turkana in Kenya as part of the Koobi Fora Research Project, which is affiliated with the National Museums of Kenya.

Their proximity suggests the two species used different food sources and behaviors to live so closely without becoming extinct.

read more HERE