hominid classification

[Ken Kinman]

Dear All,
      Having read John Grehan's comments and having read more on the recent debate on hominid origins, I am seriously considering transferring Sahelanthropus, Orrorin, and even Ardipithecus, to Pongidae (although still as the closest outgroups to Hominidae).  This would leave Family Hominidae with only two genera, Homo and Australopithecus.  Australopithecus includes as synonyms Kenyanthropus, Praeanthropus, and Paranthropus (along with some other older generic names).  Recent attempts to revive genus Praeanthropus are highly destabilizing and paraphylophobic nonsense that I find extremely disturbing (and this taxonomic move should be strongly resisted).

     Hopefully recently discovered (but yet undescribed material) of Ardipithecus will verify it's bipedality, thus bolstering it's placement in Hominidae.  The recent raising of Ardipithecus kadabba (as a separate species from Ardipithecus ramidus) earlier this year, along with its significantly older age (about 1.2 million years older) could conceivably even throw kadabba into a separate genus (either new, or part of Orrorin, or even Sahelanthropus?).  It really depends on what the undescribed material (and yet to be discovered material) shows.

     No matter what happens, a paraphyletic Australopithecus giving rise to genus Homo is unavoidable (even desirable in my opinion).  Attempts to completely cladify hominids will always result in unnecessary oversplitting, controversy, confusion, and instability.  As John Grehan has noted, more rigorous cladistic analysis is needed to clear up this mess, but a rigorous (strictly) cladistic classification is an exercise in paraphylophobic futility.

     Here's the modified classification I am considering until the bipedality of Ardipithecus is better established.  I continue to assume that the thinning of molar enamel (intermediate in A. kadabba and thinner yet in A. ramidus) is in parallel with that of genus Pan (perhaps due to a similar shift to feeding on softer foods).  If Ardipithecus species are actually ancestral to Pan, then perhaps so are genera like Sahelanthropus.  Of course, if genetic evidence is found to support Grehan's hypothesis of closer Pongo-Hominidae relationships, I will have to recode the taxa within Pongidae to reflect that, but I haven't seen any such genetic evidence presented to date.

  1  Cercopithecidae
  2  Propliopithecidae
  3  Pliopithecidae
  4  Proconsulidae
  ?  Oreopithecidae
  5  Hylobatidae
  6  Pongidae%
        1  Dryopithecus
        ?  Ouranopithecus
        2  Lufengpithecus
        B  Sivapithecus
        C  Pongo
        3  Gorilla
        ?  Samburupithecus
        4  Pan
        5  Sahelanthropus
        6  Orrorin
        B  Ardipithecus
        7  {{Hominidae}}
 _a_ Hominidae
        1  Australopithecus
       _a_ Homo