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Re: A note on pterosaur nesting behavior

On Jul 24, 2009, at 7:29 AM, David Peters wrote:

Imagine a bat baby buried.
The wear and tear on the wing and hind limb membrane as it escapes its burial chamber would be problematic.

I'm not sure that's actually true, and even if it is, it may not be applicable to pterosaurs, which seem to have possessed a wing membrane with rather different material properties from those of bats. There are living bats that dig and scramble around on the ground, so membrane wings are not as much a hazard as it might seem.

While all fossils are buried, the indications of the present three embryos do not indicate intentional burial.

How so?

If buried, evidently pterosaurs buried their eggs one at a time.

This could be the case, but why do you think that need be true?

If lepidosaurs, the eggs could have been laid within a short time of hatching, which is the present indication.

Life history variables are often quite plastic; I would hypothesize that a short incubation time would be possible for many potential phylogenetic positions. Some birds have quite short incubation times. Lepidosaurs take it even further, of course, with ovi- viviparity and the like, but I would argue that the possible incubation and nesting parameters has more to do with egg structure and physiology than phylogenetic position (except to the the extent that egg morphology happens to be phylogenetically constrained - which is rather complicated).



Michael Habib, M.S.
PhD. Candidate
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280-0181