Re: AAT Theory

Tom Clarke (clarke@longwood.cs.ucf.edu)
5 Sep 1995 09:50:49 -0400

chris brochu <gator@mail.utexas.edu> writes:

>In article <41vfus$p82@ttis.thomtech.com> Mike Reid, mreid@thomtech.com
>writes:
>>.... What
>>if fossils of a proto-hominid creature were found in late Miocene
>>nearshore marine deposits? Wouldn€t such fossils provide solid
>>evidence to support the AAT,

>Please pardon the intrusion of a crocodylian systematist into this
>discussion.

>The Miocene Calvert Cliffs Formation produces a rich diversity of
>vertebrate fossils, including large sharks, bony fishes, whales, and
>crocodylians. Based on sedimentological evidence, the depositional
>environment was probably coastal or nearshore marine.

>The Calvert Cliffs Formation also includes the remains of horses and
>camels. These ungulate bones are probably more abundant in the Calvert
>Cliffs than hominid bones are in their respective settings. Does that
>imply that these horses and camels were aquatic?

An interesting question!
What does the presence of horse and camel fossils in a coastal or
near shore depositional environment imply?
Certainly it implies that the camels and horses at least visited
the littoral zone with enough frequency that some died and were
fossilized in large enough quantities to be noticed by systematic
crocodylians :-)

I am still bemused by the resistance of most professional palentologists
to the AAH. Admitedly E. Morgan used some hyperbole in her original
advocacy of the AAH, but this should not prevent the good explanatory
aspects of the AAH from being considered. Perhaps if it had
been called the Littoral ape hypothesis...? To me considering the
aquatic environment as an element in hominid evolution as well as
forest and savannah (and later glacial) can add much to what
is now unclear. Hominds living at the edge of the water, feeding
from trees, from such savannah as existing, from the water,
subject to selection pressures for true bipedalism arising from
feeding in the littoral zone. Later the bipedal posture "perfected"
at the shore has adaptive value on the savannah etc etc.

Too bad some AAH advocate did not make the statement prior to
the discovery of Lucy (which could have been made):
"Any fossil hominid found of an age of about 4 million years will
be fully bipedal." Before lucy the conventional wisdom was that
4 million year old fossils would be tranitionally bipedal.
Such a prediction would thus have been very powerful evidence for
the AAH.

Tom Clarke

-- 

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