The theory that tools are a characteristic feature of homo is challenged: At a site near Lake Turkana in Kenya a team  led by Sonia Harmand of Stony Brook University in New York found a number of artifacts that were by flaking. However, the place was dated later 3.3 Millions year ago, eliminating as the possibility that a homo has done the flaking since they did not exist at that time. The run is now open for the any ancestor who preceded the homo genus and still used tools. (from nature)