Dennis Etler has been going great guns on his blog, Sinanthropus.
Last week’s article claiming cutmarks on A. afarensis-aged fauna from Dikika (Australopithecus afarensis used stone tools) got Dennis to write a provocative post: “Its time to sink the genus Australopithecus redux.”
Either A. afarensis should be revised to H. afarensis or the possibility must be entertained that the Woranso-Mille individual and the maker of the stone tool cut marks at Dikika represent a new previously unknown species of Homo (perhaps H. antiquus Ferguson 1984) that lived contemporaneously with A. afarensis.
He mentions the relevance of the Woranso-Mille skeleton (which I haven’t yet gotten to here) and A. sediba for this conclusion. Etler’s earlier post, “It’s time to sink the genus Australopithecus”</a> goes into more detail on these remains.
To me, the key question is whether Homo as we understand it now (including H. habilis) is polyphyletic. One way to escape this question is to narrow our genus, placing H. habilis and its ilk into Australopithecus. But Australopithecus defined broadly in this way is almost certainly paraphyletic. And that’s without considering the issue of robust australopithecines. I can see why one might follow Ernst Mayr and stick them all in Homo.