[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Large last gasp of pterosaurs



----- Original Message -----
From: "David Marjanovic" <david.marjanovic@gmx.at>
To: "DML" <dinosaur@usc.edu>
Sent: Thursday, January 22, 2004 1:25 PM
Subject: Re: Large last gasp of pterosaurs


> > There is no direct evidence of bad flying weather.
>
> Either we have next to no idea at all about what happens when a mountain
> falls from the sky. Or the impact produced lots of bad flying weather.
>
> Not quite direct evidence, but an IMHO reasonably safe inference.
>
> > > What makes you think that pterosaurs were particularly limited in
their
> > > terrestrial agility?  I've not seen any evidence of that in either
their
> > > skeletons or their trackways.
> >
> > I'm a victim of pop science portrayal of guy on crutches hypothesizing Q
> > terrestrial movt on Making of WWD--was this way off?  Sorry.
>
> Yes, it was off. Not all that far, but... give me crutches that lengthen
my
> arms by just some 30, 40 cm, and a webcam, and you'll see me gallop
> elegantly (assuming that my legs aren't still too long, so that I'd step
on
> the crutches). I've seen an animation of a pterosaur walking _fast_ and
very
> smoothly in a track found in Crayssac. For a step or two it seems to be
> galloping.
>

It is unwise to make general statements about all pterosaurs based on any
single example, just as it is unwise to suggest that all great apes are
brachiators because gibbons are.  While the wonderful trackways of Crayssac
and others from the American Jurassic demonstrate that some small
pterodactyloids were excellent walkers and runners, they do not tell us much
about the large pterodactyloids of the Upper Cretaceous in which the wing
metacarpal was hyperelongate.  One can reconstruct Pteranodon,
Quetzalcoatlus, and Nyctosaurus in quadrupedal walking postures, and I agree
that they all could walk quadrupedally, but that does not demonstrate that
they were quick or agile or spent a lot of time walking around.  The
hyperlengate wing metacarpals result in an ungainly forelimb.

Chris


S. Christopher Bennett, Ph.D.
Assistant Professor of Basic Sciences
College of Chiropractic
University of Bridgeport
Bridgeport, CT  06601
http://www.bridgeport.edu/~cbennett

"Savor the sun--but when the clouds come make animals"  (Hexum)