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Re: Patagium attachment Was: Re: Pterosaur.net



I'm not aware of any preserved membrane for which the trailing edge of the membrane in the vicinity of the elbow is located more than about 45% of the length of the humerus behind the elbow. As Mike points out, that has no implications whatever for the extent of the hindlimb attachment, which may be quite variable between species, and even possibly non-existant in some (I'm not pushing that latter scenario -- just pointing out that the fossil materials don't yet exclude it). Personally, I suspect that hindlimb attachments may have been quite variable both between species and across the eons -- but, I do not see any current evidence for broad wings. The narrow wing implies a fairly tight radius for the trailing edge of the wing membrane in the vicinity of the elbow as the membrane fillets into the hindlimb and also weakly implies that the fillet was not normally heavily loaded.
JimC

----- Original Message ----- From: "Mike Habib" <habib@jhmi.edu>
To: <davidpeters@att.net>
Cc: "Mark Witton" <Mark.Witton@port.ac.uk>; "jrc" <jrccea@bellsouth.net>; <dinosaur@usc.edu>; "Mike Hanson" <mhanson54@comcast.net>
Sent: Tuesday, January 19, 2010 11:50 AM
Subject: Re: Patagium attachment Was: Re: Pterosaur.net


On Jan 19, 2010, at 10:27 AM, David Peters wrote:

It would probably help in understanding. Jim, if this model wing of yours is a deep wing attached to the ankles or a shallow wing attached at mid thigh. I'm guessing the former because you mentioned, "Increasing the inner wing tension of the retracted wings during a dive by use of hindlimb positioning..."

Just worth noting here that a wing can be attached to the ankles and still be primarily narrow in its chord through most of its length. Therefore presuming a broad or narrow overall wing, based only on attachment, is a error. The outboard wing in every well preserved brachiopatagium is narrow. At the same time, several specimens seem to show some hindlimb attachment - the most simple explanation is therefore that the attachment was broad but the wing was narrow.

Cheers,

--Mike


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