Public Release:  Discovery supports theory of a single species of ancestor

Yale University

New Haven, Conn. - The discovery of a million-year-old skull in Ethiopia indicates that a single species of human ancestor, Homo erectus, ranged from Europe to Africa to Asia in the Pleistocene era, according to the cover article in the March 21 issue of the journal Nature.

The finding by the research team, which included Elidabeth Vrba, a Yale professor of paleontology in the Department of Geology and Geophysics, contradicts recent suggestions that there was a fundamental, early split in the homolineage between Eurasiatic and African populations.

"This find puts that into perspective," said Vrba. "This says a single species was very widespread in Africa and Eurasia."

The team was led Tim White, a professor at the University of California at Berkeley, and co-director of the Laboratory for Human Evolutionary Studies in the Museum of Vertebrate Zoology, and Berhane Asfaw of the Rift Valley Research Service in Addis Abbaba, Ethiopia.

The skull was found at a new site in Ethiopia's Afar Regional State near the village of Bouri in the Middle Awash study area.

The researchers spent two years removing the skullcap from the matrix of sediment that had tightly held it for a million years. Asfaw described the fossil as one of Ethiopia's most important.

The team's detailed analysis compared characteristics of the new fossil with other hominids from Africa, Europe and Asia. The analysis showed that it is impossible to cleanly segregate Homo erectus crania from different continents.

"They show mosaic resemblances," Vrba said. "One does not get one set of character states in each area, which suggests genetic continuity between them. There was movement and mobility between the populations, and interbreeding, consistent with a single species which should bear the name Homo erectus."

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