Bat wing digits (was Re: Tiktaalik)

[David Peters <davidrpeters@earthlink.net>]

Re: bat wing


<http://www.pnas.org/cgi/content/abstract/0509716103v1> wrote:

This absence of transitional forms in the fossil record led us to look
elsewhere to understand bat wing evolution.


Everyone looking for transitional forms in bats has been staring too
long at the wings and not looking at all at the rest of the bat. Same
thing happened in pterosaurs awhile back and some guy without a PhD
figured out the phylogeny based on the feet.


Interesting thing about bat embryos: They start off with incredibly
large hands, as large as the skull, and the metacarpals are widespread
from the beginning. Starting with that original limb bud, there is no
cell death between the fingers, as in virtually all other tetrapods. But
then the hands stop growing and they're not so big as one might assume
at birth. Then, with a dose of mother's milk, they grow to adult
proportions.

DP
StL