Since H. habilis and A. robustus emerged at the same time, it is very unlikely that one was the ancestor of the other. The gracile Australopithecines were also contemporaries of Homo habilis but much more ancient. It is therefore possible—although by no means certain—that both H. habilis, with a promising evolutionary future, and A. robustus, an evolutionary dead end, arose from the gracile A. africanus, who survived long enough to be their contemporary.
