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Re: Patagium attachment Was: Re: Pterosaur.net



On Jan 18, 2010, at 8:37 AM, David Peters wrote:

For some reason a group of pterosaur experts have been applauding this sort of nonsense lately (pterosaur.net; Unwin, 2004). Sad. You're right, Mike. The uropatagia were split, as in Sharovipteryx and Pterodactylus [phylogenetic bracketing tells us that if not good ole observation].

The bracket only predicts split uropatagia in basal pterosaurs if 1) your outgroup is correct (and that is still quite contentious) 2) there are no fossil taxa within the bracket that have a broad uropatagium. As it turns out, even if you decide to argue #1, the bracket fails on #2: several basal taxa appear to preserve a broad uropatagium. Brackets only give the null model, they do not override existing anatomical evidence.

... Add more meat to those thighs to match the extent of the ilia.

Mark's hindlimb builds seem to be quite reasonable to me. There are traces of the anterior thigh compartment in some specimens when viewed under UV illumination (the most recent Anurognathus, for example) - these show that the thigh musculature, while hardly scrawny, was not as thick as you suppose. In all likelihood, a very broad iliacus ran from the anterior edge of the expanded ilium to the proximal femur, but the other anterior thigh muscles seem not to have run that far anteriorly, so the overall thigh was not terribly deep. This is not actually a surprise, if one looks closely at the particular part of the ilium which is expanded in pterosaurs.

Cheers,

--Mike Habib


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181