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Re: A few questions about pterosaur anatomy



----- Original Message -----
From: <ee555@freenet.carleton.ca>
To: <dinosaur@usc.edu>
Sent: Wednesday, December 17, 2003 10:35 AM
Subject: A few questions about pterosaur anatomy


> I am looking for highy detailed images of membrane impressions of
pterosaurs
> (particularly the Rhamphorhychids at the British Museum of Natural
history).
> Does anyone know where I could find some?
>

How detailed?  If I remember there is a good photo of the Zittel wing of
Rhamphorhynchus in Padian and Rayner's 1993 paper on pterosaur wings
(Padian, K. and J. M. V. Rayner.  1993.  The wings of pterosaurs.  American
Journal of Science, 293-A:91-166).  There are also some new photos of
pterosaur wing membrane in Frey et al.'s paper in the Pterosaur Symposium
volume.

> I have a few more questions as well:
> Do you know were I could find muscle reconstructions or detailed drawings
of
> the wing bones of some Rhamphorhynchids and other pterosaurs?
>

I reconstructed some muscles in my paper in the Symposium volume.
Wellnhofer (1975.  Die Rhamphorhynchoidea (Pterosauria) der
Oberjura-Plattenkalke Süddeutschlands.  Palaeontographica,  A 148:1-33,
148:132-186, 149:1-30.) illustrated lots of Rhaphorhynchus bones.

> What is the back of the lower jaw of Pterodon like? Is there any evidence
to
> suggest a neck pouch?
>

You mean Pteranodon?  If I remember correctly Pterodon is a really neat big
doglike mammal with a tiny brain.  Pteranodon is illustrated in my 2001
paper:  2001 Bennett, S. C.  The osteology and functional morphology of the
Late Cretaceous pterosaur Pteranodon.  Palaeontographica, Abteilung A,
260:1-153. Do ostriches have neck pouches?  I do not think there was
anything more pouchlike than what one can see in ostriches, and there is no
evidence whatsoever of a pelican like pouch.  Comparisons to pelicans by
Eaton were ill-advised.


> The angle of the pteroid bone is often shown in reconstructions with its
> angle being less than thirty degrees from the forearm. Is there any
> possibiliy that the angle was higher? If it was closer to ninety degrees
> could it have been used to control the angle of the leading edge of part
of
> the membrane?
>

That sort of reconstruction was championed by Frey and Riess (1981.  A new
reconstruction of the pterosaur wing.  Neues Jahrbuch für Geologie und
Paläontologie Abhandlungen, 161(1):1-27.) and subsequent papers by Frey with
various other people.  I do not accept their reconstructions, but what do I
know?


> How extensive was the decline of pterosaurs through the Cretaceous? How
many
> families were left and is it true that most groups under a metre in wing
> span had been out-competed by this time? Does this trend extend back into
> the Jurassic?
>

The fossil record of late Late Cretaceous pterosaurs is very poor and it is
not clear whether it reflects a real reduction of pterosaur diversity.

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)