Re: Lucy
Phil Nicholls (pn8886@csc.albany.edu)
15 Jan 1995 01:01:56 GMT
In article <3f9e9t$d5s@srvr1.engin.umich.edu>,
David M woodcock <dmw@engin.umich.edu> wrote:
> --David
>
>Ok Chris, why do you think Lucy is not an ancestor of Homo?
I'll give two reasons. The first has to do with the variability
found in the various Hadar materials. I agree with those who feel
there is more than one species there.
The Latoeli footprints often assigned by default to A. afarensis
show now curvature in the toes and are, at least according to
Russell Tuttle, identical to those of modern Homo sapiens. Lucy
would have left very different footprints, indicating some curvature
in the toes. This suggest that the Latoeli footprints were made by
another hominid, one that has not yet made a definitive appearance
in the fossil record.
A second, more technical reason, has to do with the drainage of
blood from the cranial vault. Robust Australopithecines, which
are widely seen as NOT ancestral to Homo, have an enlarged
occipital-marginal sinus (O/M sinus). Gracile Australopithcines
and Homo do not have an enlarged O/M sinus. They have the normal
Transverse-Sigmoid sinus drainage pattern (also found in
chimpanzees). Lucy has an enlarged O/M sinus as does the
"male" A. afarensis Johanson unveiled last year (AL-444).
I believe Lucy is an early robust australopithecine and is too
derived to be a direct ancestor of Homo.
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
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