RE: polarity of bipedality in dinosaurs

["Cunningham, Betty" <Cunningham@sega.com>]

From: "Jonathan R. Wagner" <znc14@ttacs1.ttu.edu>

 >         Excess digits don't seem to hamper bats,

from swf@elsegundoca.ncr.com         sarima@ix.netcom.com

>Except that bats don't really have any "excess" fingers - they are
>all used as *part* *of* *the* *wing*. In the protobirds only one finger
>was involved in the wing, the others *were* excess as far as flight
>was concerned.

What function does a bat's thumb play as a flight mechanism?
 From what I've seen of them, they're more for hanging from and assisting   
in climbing and grasping-all functions of a hand or foot rather than a   
'wing'.  And those disc-thumbed bats for wedging.  Bats' thumbs don't   
seem to have any great attributes for flight, :ie: airodynamic shape.  I   
just assumed  they  tucked them when in flight so as to use the membrane   
that forms between their humerous and their body as their leading edge   
for flight.

 -Betty