[Taxacom] Ardipithecus

[Kenneth Kinman]

Dear All,
      I have only begun to digest some of the new information concerning
Ardipithecus.  However, it is already clear that its bipedal
characteristics seem to necessitate that I return it to the base of
Family Hominidae rather than part of a Pongid clade outgroup to
Hominidae containing Ardipithecus and Orrorin.  In particular, the
intermediate enamel thickness of Ardipithecus makes it clear that this
characteristic is too labile and subject to convergence to be very
useful in tracing hominid origins.  Characteristics associated with
bipedality are far more valuable, even though they are not as commonly
preserved as teeth.  Look skeptically on those who use enamel in their
arguments (if you weren't already).
       Future discoveries of Orrorin material may or may not show it to
be a Ardipithecus sister group that must also be placed in Family
Hominidae, but its older age makes it best retained in Pongidae as a
sister group to Family Hominidae as a whole, not of Ardipithecus alone.
Therefore, that is how I expect to code it in my next classification.
Whether Sahelanthropus split off before or after the chimp divergence
remains to be seen.  I suspect it will split off just after that
divergence, and will be sister group to Orrorin + Hominidae (including
Ardipithecus).  Whether Gorilla and Pan clade together or not still
awaits whole genome analysis that I am still anxiously awaiting.  
       --------Ken Kinman