Scientists working in Ethiopia have discovered a new species of human ancestor and the earliest-known evidence of butchery of animals.
The two findings, which date to 2.5 million years ago, are described in separate papers in the April 23 issue of Science.
Part of the skull, braincase, jaw, and limb bones of what appears to be a new, direct human ancestor -- an evolutionary link between Australopithecus and the genus Homo -- were described by a team of paleoanthropologists led by Berhane Asfaw, of Ethiopia’s Rift Valley Research Service, and Tim White, a professor of integrative biology at the University of California at Berkeley.
In 1992, the same team found remnants of Ardipithecus, the earliest-known hominid, while working in the same area, known as the Middle Awash site, in the Afar desert.
The latest specimen, named Australopithecus garhi, not only adds another ancestor to the human family tree, but also shows scientists that the hominid thighbone had become elongated by 2.5 million years ago, a million years before the forearm had shortened to create the familiar proportions of modern humans.
The scientists said the combination of bony and dental features in the fossils was unanticipated. As a result, they named the specimen “garhi,” which means surprise in the Afar language.
In the second paper, a team that was headed by Jean de Heinzelin, of the Royal Institute of Natural Sciences, in Brussels, and also included Mr. White and J. Desmond Clark, a professor emeritus of anthropology at Berkeley, showed that antelopes and horses had been butchered at the same site, with the earliest-known stone tools.
Those bones and the fossils of the new human ancestor were found in eroding sediments along what was once a lake near the Afar village of Bouri.
The scientists said the evidence of butchery demonstrated that the earliest stone tools had been aimed at getting meat and marrow from large mammals, a revolution in the diet of hominids that may have paved the way for their invasion of new habitats and continents.
While the researchers suggested in their paper that A. garhi was probably responsible for the broken animal bones and stone tools, Mr. White said he and the other authors “cannot yet conclusively link the new species with the butchery.”
http://chronicle.com
Section: Research & Publishing
Page: A19