Re: Bipedalism and theorizing... was Re: Morgan and creationists

Gerrit Hanenburg (
Tue, 23 Jul 1996 16:57:33 GMT (HARRY R. ERWIN) wrote:

>: But it *is* another form of orthograde positional behavior,meaning
>: that it is positional behaviour in which the long axis of the body is
>: more or less perpendicular to the horizontal plane,just like in
>: brachiating,suspension and vertical climbing and leaping.
>: In al these forms of orthograde positional behavior primate infants
>: are able to cling,whether or not these movements are slow or fast.

>Oxnard has some wonderful pictures of this in some of his books.

"The Order of Man" has certainly expanded my ideas of locomotor
behavior and anatomy.
"Animal Lifestyles and Anatomies:The Case of the Prosimian Primates"
is even more interesting in that it is an attempt to integrate this
information with ecology.

>Actually, there's some question whether the plesiadapiforms or the bats
>are more closely related to euprimates.

What about Scandentia?

>: It may be reasonable to assume that reduced bodyhair characterizes the
>: origin of Homo sapiens but it is not reasonable to shift this to
>: A.afarensis without an indication.A.afarensis may well have retained
>: the primitive state.
>: Parsimony is not in question.The hypotheses that reduced bodyhair
>: originated first in A.afarensis or in H.sapiens are equally
>: parsimonious.

>And completely untestable without much better material than we have. I
>suspect body hair reduction occured with the emergence of H. erectus.

That's what I suspect too,assuming that the reduction of bodyhair is
related to thermoregulation and given the skeletal features that seem
to indicate adaptation to deal with heatstress (high radial and crural
indices,small bi-iliac breadth)
It may even have occured in Homo rudolfensis but the association of
cranial and postcranial material in this species is quite uncertain.