Re: Earliest Hominids

Harry Erwin (
Thu, 29 Jun 1995 22:09:31 -0400

In article <3su7qh$>, Alex Duncan
<> wrote:

> In article <3sp58o$> HARRY R. ERWIN,
> writes:
> >I thought this, too, until I saw Holloway, Early Hominid Endocasts, in
> >Tuttle, where he used a figure of 20 kg for A. africanus. His arguments
> >make sense, too. It's a question of how much flesh you put on those bones,
> >and 28-30 kg corresponds to a moderate degree of robustness, while 20 kg
> I'm unfamiliar w/ this particular Holloway reference. More details?
in Tuttle, Primate Functional Morphology and Evolution, Mouton & Co, 1973.
> Estimating body weight is problematic. I find it encouraging, however,
> that regression equations using EITHER human or ape (or combination)
> derivations for either articular surface dimensions or diaphyseal
> dimensions seem to agree on around 28 - 30 kg for AL 288, and for Sts 14.
> I agree that as we go back further, we might expect to see hominids
> getting smaller and smaller. I suspect A. ramidus will turn out to be
> smaller than the other Australopithecines, and that our common ancestor
> w/ chimps may have weighed 10 - 15 kg.
BTW, I understand the post-cranial skeleton of A. ramidus is
indistinguishable from A. afarensis...

I think, though, you've got my gist. You're the expert; I'm just the modeler.

Harry Erwin
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PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"