A. ramidus as test case for AAT

Alex Duncan (aduncan@mail.utexas.edu)
11 Jul 1995 17:53:48 GMT

I want to see some evidence of aquatic adaptations in the earliest
hominids and in their antecedent hominoids before I lose my healthy

-- Ralph Holloway

The argument about AAT is ridiculous. As Dr. Holloway has noted,
proponents of the AAT have a dogmatic fervor about them (e.g. they keep
raising the same points over and over again, even after they've been
refuted. It reminds of creationists screaming "there are no
intermediates in the fossil record" after you've shown them an
Archaeopteryx or the sequence of hominid evolution.) I can think of
nothing I can say that will make any of you change your minds, and so,
after this last blast, I withdraw from the debate, and will keep my posts
to more substantial matters (well, actually I reserve the right to be
inconsistent here).
At any rate -- to the title of this post. One criterion for a
successful scientific theory is that it should be able to make testable
predictions about the world. It has been rumored (even mentioned in
Nature or Science, I think) that much of the postcranial skeleton of an
A. ramidus individual has been discovered by White et al. As A. ramidus
existed somewhere between 3.9 and 4.4 Myr ago, it was extant right at the
end of the hypothesized period of aquatic adaptation in the Afar
triangle. If I've read the AAT posts correctly, they're proposing a
period of about 3 Myr (from 7 to 4 Myr) during which hominids were
predominately aquatic. As evidence of the very end of this period of
time, we might expect the postcranial skeleton of A. ramidus to show some
adaptations to an aquatic existence (in fact, after 3 Myr in the water,
we might expect them to show very STRONG skeletal evidence for an aquatic

So, a test case for you AATers out there: predict for us what the aquatic
adaptations of the postcranial skeleton of A. ramidus will be. And a
caution: if your predictions are exactly the same as the ones the rest of
us make based upon our well known biases toward arboreal/terrestrial
adaptations, then we will have the final evidence that AAT is
intellectually empty.

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