Re: Webbed Foot in South Africa?

Alex Duncan (
19 Sep 1995 23:36:52 GMT

In article <43mcrg$> Tom Clarke, writes:

>In the Oct 95 Sci American there is an article about
>a find by Ronald Clarke and Philip Tobias of a 3.5 MY old
>fossil in South Africa which was apparently bipedal and also
>had a splayed/diverged big toe. [The original report
>is in Science, but I missed that]
>There is apparently some controversy about the meaning
>a bipedal foot with a diverged big toe. Most incline
>toward some interpretation involving arboreal bipedalism,
>or else toward saying that the diverged big toe is a mistake.
>I know this suggestion will be anathema to many, but
>could the diverged big toe be some remnant of a webbed
>foot adapted to a littoral environment as in the aquatic
>ape theory?

I refer you here to Chris Brochu's comments about cladistic
reconstruction. Humans are the only primates that don't have divergent
large toes. In all other primates the abductible hallux is most
reasonably interpreted as an adaptation to living in the trees. In NO
other primates do we any sort of webbing of the nature required to
increase efficiency in aquatic locomotion. In addition to all of this,
in A. africanus and all known older hominids, there are other features of
the skeleton that are most reasonably interpreted as adaptations to
occasional arboreal behaviors. In other words, the abductable hallux is
a (probably still functional) plesiomorphic feature. Given the nature of
its occurence in other primates, and what we know about the postcranial
anatomy of Pliocene hominids, there is no reason to interpret it in any
other way.

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086