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Re: Pterosaur take-off movie on the NG site

A couple of comments inserted.

----- Original Message ----- From: "Mike Habib" <habib@jhmi.edu>
To: "David Peters" <davidrpeters@charter.net>
Cc: "dinosaur mailing list" <dinosaur@usc.edu>; "Mike Habib" <mhabib5@jhmi.edu>
I disagree that the wing goes from the outboard tip the elbow - there are several fossils showing that the trailing edge passes about 50% of the humeral length behind the elbow. Where it goes from there is a matter of debate, because the more elastic mesopatagium is generally a mess (or missing) in most specimens, even those that have a nice outboard wing preservation.

The most I've seen is about 40% -- pretty durned close to half.

4. The forelimbs are quite wide. A more efficient vector would have the limbs directly beneath the shoulders.

Moving the limbs inboard doesn't noticably affect the efficiency of the launch vector.

Yes, but they cannot get there. We constrained the forelimb postures according to published estimates of possible joint excursions (which we confirmed with the original specimen as best we could). Anhanguera appears to have been a relatively wide-gauge animal up front. Other pterosaurs were probably not so wide gauge.

I too, see Anhanguera as relatively wide gauge.

This relegates Anhanguera to a weak bipedal hindlimb propulsion (knees bent) with support, not propulsion, coming from the wings.

Not at all.  Various gaits are possible.

and I would not expect it to be capable of a canter or gallop, as I suspect that most azhdarchids were.

I strongly suspect the possibility of a 3-beat canter in most azhdarchids.

3. Whenever an animal leaps into the air (think of frogs, kangaroos and basketball players), after the leap the legs extend straight back trailing the rest of the body in the line of the trajectory

One wouldn't expect that to be the case in the case of pterosaurs :-)

I would not be surprised if there were a leading edge tendon in the propatagium for pterosaurs.

I would. There is no need for such a leading edge tendon, and it would create some disadvantages. Should it exist in some pterosaurs (and it is possible -- some years ago, I thought they were likely), I would expect the lack of evolutionary advantage to make its presence quite variable between species.

Note that the presence of such a tendon does not prevent relatively heavy extension of the elbow and a quad launch, as evidenced by the fact that bats have such a tendon, and quad launch well.