Deep roots for the genus Homo

Abstract

Fossil jawbone pushes back origins of our genus by 400,000 years. In two papers online this week in Science , researchers introduce a partial lower jaw from Ethiopia as the oldest known member of the genus Homo . Radiometrically dated to almost 2.8 million years ago, the jaw is a window on the mysterious time when our genus emerged. With both primitive and more modern traits, it is a bridge between our genus and its ancestors and points to when and where that evolutionary transition took place. Together with a reassessment of known fossils, published in Nature this week by paleontologist Fred Spoor and colleagues, the find is stimulating new efforts to sort out the mixed bag of early Homo remains and to trace how they are related to their australopithecine ancestors.