Re: More on the Jeholopterus pycnofibre study

["jrc" <jrccea@bellsouth.net>]

comments inserted.
JimC

----- Original Message ----- 
From: "David Peters" <davidrpeters@charter.net>
To: "dinosaur mailing list" <dinosaur@usc.edu>
Sent: Friday, August 28, 2009 5:53 AM
Subject: re: More on the Jeholopterus pycnofibre study


> In bats the wing shape is dynamic and ever-changing, tightening and 
> stretching between the various elements (several fingers and the hind 
> limbs). In birds the wing shape is more constrained by the orientation  of 
> the stiff feathers of unyielding length and the bending of the  elbow and 
> wrist. The hindlimbs are not involved. Which of these two  are pterosaurs 
> more similar to?

Neither.

> Certainly the forelimb membrane has  the flexibility to extend as a wing 
> and contract to almost nothingness  during folding, as in bats, but 
> pterosaurs have only one wing finger  and the akinofibres restrict the 
> shape of the wing.

Actually, within the limits of their range of motion, they modulate the 
shape of the wing, rather than restricting it.