Re: Lucy

Stanley Friesen (
Sun, 15 Jan 1995 23:45:24 GMT

In article <3f9s64$>,
Phil Nicholls <> wrote:
>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.

Hmm, is this still being debated? I thought it was close to settled?

Relating to this:

How does the variability of the "First Family" (A.L. 333) series
compare with that of the rest of the afarensis hypodigm?
>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.

How do the Laetoli prints compare to the larger specimens assigned
to afarensis? Lucy, being one of the smaller series, may not be
diagnostic of the larger series.

>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.
The difficulty I have with this argument is that at this low a
taxonomic level reversals are easy, and probably common. Thus
I am not entirely sure that such derived features are sufficiently
fixed to conclusively rule out ancestry. [And, unless there
is more to this than I can see, an enlarged sinus is an extremely
*simple* character - one subject to simple gradational variation
- and is thus *particularly* subject to reversal, much like size
and other simply metric characters].


May the peace of God be with you.