Re: An alternative to ST and AAT

Susan S. Chin (
Sun, 10 Nov 1996 17:01:43 GMT

John Waters ( wrote:
: Rohinton Collins <> wrote in
: article <01bbcdb9$208a50c0$424698c2@dan-pc>...

: > > JW: For what it's worth, the HBT explains that the
: hominid
: > > delay in switching to a highly efficient form of
: bipedalism

: JW: I was assuming that Paul was referring to early
: Australopithicenes, which had a morphology similar to that
: of Chimpanzees.

Early Australopithecines such as A. afarensis and A. africanus did have a
morphology similiar to that of Chimpanzees. However, this applies
primarily to dental and cranial traits, limb proportions, and their
curved phalanges (am I missing anything here?)

As far as postcranial adapatations for bipedalism, Lucy's pelvis clearly
shows A. afarensis has already undergone extreme changes which enabled
afarensis to walk bipedally for extended periods of time if necessary.
This isn't a chimp-like morphology at all. Same goes for her and other
afarensis knee joints found. If there are chimp-like morphological
characters in early Australopithecines, they are likely primitive
retentions of an arboreal ancestry. Which isn't to say Austra. didn't
climb trees, but when they did, they walked upright to get there.

: JW: This morphology enables bipedalism, but is not as efficient
: for long distance walking. In this sense, the australopithicene
: bipedalism was less efficient than modern Hss.

I haven't read any of the later research on Australopithecine locomotion,
can you cite a source and some specifics for the less efficient biped claim?
What part of the Australopithecine anatomy make them less efficient? Thanks.