Re: The Peters Strikes Back (pterosaurs)

["James R. Cunningham" <jrccea@bellsouth.net>]

Jaime Headden wrote:
> It is most likely that all
> pterosaurs could assume a fully quadrupedal standing posture on the 
> substrate, ground or otherwise. The limbs could certainly move
> while on the substrate, so they could "walk;" but for some reason, it seems 
> odd to some that walking was not habitual ... even bats
> will walk if they must, however puny their hindlegs, and no pterosaur seems 
> to be as badly designed for walking as the loon is,
> quadrupedal or bipedal.

As you all know, I'm more familiar with Quetz than I am with any other
pterosaur, and based on the quetz skeleton, it seems fairly obvious to
me that they could walk quite effectively in quadrupedal mode, and
perhaps could even lope or canter (I've speculated re loping for some
time, but haven't made any effort to prove the capability yet). 
However, I have a great deal of difficulty imagining them taking more
than a few steps bipedally.  I can imagine scenarios where they would
need to do that, but not any where continuous bipedal walking or running
would be an advantage, or even possible.
 
> and though any pterosaur can assume a stable CoG while standing bipedally,

Static or dynamic?  Dynamic I can imagine (for short periods).  Static,
I can't.  Has anyone done the numbers on it yet?

Jim