7-million-year-old limb fossils may be from the earliest known hominid
Misconduct allegations over an earlier report on one of the bones hang over the findings
By Bruce Bower
In 2001, researchers unearthed a partial fossil leg bone and two forearm bones in the central African nation of Chad. Those fossils come from the earliest known hominid, which lived around 7 million years ago, and reveal that the creature walked upright both on the ground and in the trees, a new study proposes.
But a lively debate surrounds the fossils, concerning whether they actually belong to the hominid species, known as Sahelanthropus tchadensis, or to an ancient ape, and to what extent either species could have adopted a two-legged gait. These have become vexing questions as scientists increasingly suspect that ape and hominid species evolved a variety of ways to walk upright, some more efficient than others, around 7 million years ago.