Re: Habilis and robusticity notes

David DeGusta (
Mon, 17 Jul 1995 16:47:32 -0800

In article <>, (J Sharpe) wrote:

> Australopithicus robustus
> =========================
> . very robust; big muscles and bones
> Robusticity
> ===========
> . large jaws and teeth; back twice as large as humans'

This brought me (temporarily) out of lurk mode. I would be cautious about
defining A. (or P.) robustus based on large molars, as the above seems to.
For example, A. robustus molars aren't really larger than A. africanus. If
you have access to casts or photos, check out the sizes of the molars in
the following:

A. robustus A. africanus
============ =============
SK23 (mandible) STS36 (mandible)
SKX4446 (mandible) STS7 (mandible)
SKW(X) 5 (mandible) STW498 (mandible)
SKW11 (maxillae) STW384 (mandible)
TM1517 (cranium + lft maxillae) STW252 (the intact lft maxillae)

You'll find that the STW498 and STW384 molars (africanus) are
substantially larger than any of the listed robustus molars. And STS36
(though there's some matrix infilling) was almost certainly larger too.
STS7 (africanus) is at least as large as the listed robustus molars. As
for the maxillae, STW252 molars (africanus) are about the same size as
SKW11 (robustus), and probably a little larger than TM1517's molars. All
the above are adults. In fact, even the largest robustus molars that I
can think of (SK12, SK83, and SK845) are still not bigger than STW384 and
STW498 (africanus).

David DeGusta