By Bruce Bower
Researchers have discovered what they regard as the oldest known fossil from the human genus, Homo. But questions about the evolutionary status of the approximately 2.8-million-year-old lower jaw have already emerged.
Found in 2013 resting atop eroding soil in Ethiopia’s Ledi-Geraru research area, the fossil jaw contains several signature Homo features, including small and symmetrically shaped teeth, say paleoanthropologist Brian Villmoare of the University of Nevada, Las Vegas and his colleagues. The new find also contains more apelike traits found in Australopithecus afarensis, a hominid species that died out about 3 million years ago. A. afarensis fossils, unearthed at a nearby Ethiopian site called Hadar, include Lucy’s famous partial skeleton. The similarities suggest Lucy’s species may have been an evolutionary precursor of the human genus, Villmoare’s team proposes online March 4 in Science.