In 1974, anthropologists in the Afar region of northern Ethiopia found the remains of a hominid who lived 2.9-3.8 million years ago. They named her Australopithecus afarensis, or more familiarly Lucy, and some scientists pronounced her the "Mother of Mankind." However, four years ago, anthropologists found a 3.3-3.5 million-year-old lower jaw, fragments and teeth from at least three individuals - just 50 kilometers (30 miles) from where a dig had found the Lucy bones.

"There were at least two, if not three, early human species living at the same time and in close geographic proximity," said Yohannes Haile-Selassie of the Cleveland Museum of Natural History, who led a study published Wednesday in Nature.

Homo sapiens, or modern humans, appeared 200,000 years ago. The earliest known member of the Homo genus lived 2.8 million years ago.

'The earlier phases'

Australopithecus deyiremeda had both humanlike and apelike traits, as Lucy did, and probably represents one set of bones in a wider group of candidates to have directly preceded modern humans, according to scientists. "Deyiremeda" means "close relative" in the language of the Afar people. These bones, clearly different from Lucy's, bear teeth of different size, shape and enamel thickness and a more robust lower jaw, according to the study, suggesting that the hominids had different diets.

"I think it is time that we look into the earlier phases of our evolution with an open mind and carefully examine the currently available fossil evidence rather than immediately dismissing the fossils that do not fit our long-held hypotheses," Haile-Selassie said.

Scientists estimated the fossils' age from radioactive dating of the soil and "paleomagnetic" data, which traces changes in Earth's magnetic field, recorded in iron-bearing sediment. And while no one doubts the close relation, at least one voice in Haile-Selassie's expected maternity dispute has emerged.

"Anatomical variation within a biological species is normal," UC Berkeley evolution expert Tim White wrote in an email to the Associated Press news agency, explaining that he thought the latest find actually came from Lucy's species. "That's why so many announcements of this sort are quickly overturned."

mkg/rc (Reuters, AFP, AP)