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RE: Arms into wings
<So, don't look at the forelimbs of shrews etc. to get a glimpse at the
condition in the ancestors of bats, when those of other archontans
probably
give us a much closer glimpse.>
My point remains, however, that you shouldn't look at bats to get a
glimpse of the prey capturing function of forelimbs in bird ancestors.
<Sure they did: *AFTER* they had become ornithothoracines! However, the
hands of _Archaeopteryx_ and even _Confusciusornis_ retained quite a bit
of grasping ability (as various morphometric and morphological studies
have suggested). After all, there are few morphological differences
between the forelimbs of Archie and dromaeosaurids.>
I guess I'm suggesting that overall function of the arm and hand as prey
capturing devices must have been compromised over time once selection
began acting to improve aerodynamic performance. If you are running
after a dragonfly and flapping, you can't also be grabbing for it with
your hands-- at least not without breaking the flapping rhythm. The
process involved a fundamental shift in the function of the arms and
hands from prey capture to flight. The carpometacarpus was simply the
coup de grace.