orangutans and human origins again

John Grehan jgrehan at TPBMAIL.NET
Wed Oct 1 00:14:21 CDT 2003

I'm still having trouble finding a list of synapomorphies that link fossil
taxa such as Australopithecus with humans. So far all I have come across
are generalities such as bipediality and canine taking on an incisor
function. These two features alone may qualify as synapomorphies, but
without corroborating characters one might wonder whether there was more
than one lineage of upright walking apes, of which only one or some where
immediately part of the human lineage. Some proposed hominids, such as
Ardipithecus and Sahelanthropus don't appear to have anything much at all
to suggest a specifically hominid position, especially in the context of an
orangutan-human clade since the two fossils appear to lack thick dental
enamel and possibly also lack low molar cusps. Anyway, should anyone know
offhand other proposed synapomorphies linking fossil hominids with Homo I
would be most grateful for the citation (and also synapomorphies purporting
the monophyly of a clade comprising humans, chimps, Australopithecus,
Orrorin, Ardipithecus, and Sahelanthropus). Lots of literature out there
and I have admittedly covered only a small part so far.

John Grehan

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