Re: Quetzalcoatlus may have lived like a giant stork

[Michael Habib <mhabib5@jhmi.edu>]

> Keep in mind that while the distal wing is reduced, the outer part of 
> the proximal wing and the inner part of the distal wing are greatly 
> expanded. MC IV is relatively much longer than in most pterosaurs, as 
> is Ph IV-1, and the aspect ratio is still quite high.

True, good point.  Just the same, the overall span seems a bit reduced 
relative to mass in comparison to other large pterosaurs, as best I can 
tell.  The aspect ratio is still high, but not of the grade of some 
other large pterosaurs (ornithocheirids and pteranodontids being the 
obvious examples), so I still suspect that there is some adaptation to 
reduce the inertia of the wing.  Of course, there are other effects of 
shortening the distal wing elements, especially when expanding others 
more proximally (especially with regards to expanding MC IV).

> And, keep in mind that the distal wing of Qn is expanded relative to 
> the distal wing of Qsp while the somewhat transversely held r/u is 
> relatively reduced in length, so the allometry involved in increasing 
> the size of the animal is also increasing aspect ratio at the same 
> time.  Qn has a higher aspect ratio than Qsp.

Quite interesting, but not terribly surprising.  I somewhat expected 
that Qn would have a higher AR than Qsp.

> The following is speculative.  I haven't investigated it, but may 
> someday. It would please me if someone else would go on and look into 
> it now (hint, hint, Mike).  I suspect that Quetz and a number of other 
> pterosaurs may have been capable of either a pacing gait or a 3-beat 
> canter (or both) that could have been quite speedy on the ground.  
> These animals were not terrestrial klutzes.

I have similar suspicions. David Hone actually mentioned the idea of 
pacing gaits to me recently regarding pterosaurs, as well.

Cheers,

--Mike H.