Re: Did pterosaurs feed by skimming?

[Michael Habib <mhabib5@jhmi.edu>]

I agree that Mark answered very well.  Tossing in my extra two cents, I 
think there is a general tendency to underestimate the degree of 
hypertrophy involved in the hind limbs of raptorial birds (and thus to 
assume similar abilities in various other creatures inappropriately, 
especially pterosaurs).  Falconiform and Strigiform birds pack a 
wallop; their hind limbs are much more robust than many realize and 
generate almost terrifying forces.  This means that the mechanical 
loads across the entire limb are quite high, and the upshot is that 
there is a distinct strength signal in the hind limbs of raptorial 
birds.  Even using the femora alone shows this signal; only some diving 
birds (such as loons) have higher mass-specific femoral bone strengths 
than raptorial birds.

By way of comparison, while pterosaur femora aren't necessarily weak 
(though some are), they do not have anything like the biomechanical 
adaptations seen in hawks, eagles, falcons, and owls.

Cheers,

--Mike H.


On Thursday, July 26, 2007, at 11:33  AM, Mark Witton wrote:

> "Could pterosaurs in general or certain genera used their feet to hold
> struggling animals?"
>
> As Jim has already stated, this trick has been played up lots in films
> (yer One Million Years B.C.s, Jurassic Park IIIs etc.) but doesn't
> really have much basis in reality. The grasping ability of pterosaur
> feet, to my knowledge, is still understudied, but a cursory glance at
> their pedal morphology suggests their ability to grasp things,
> raptor-style, was limited. Unlike raptorial birds, pterosaur phalanges
> lack the developed flexor tubules we would expect in an animal with a
> sturdy pedal grip, and their foot bones are generally slender anyway,
> implying they weren't used in any apprehensive fashion...