Re: Question

[Dann Pigdon <dannj@alphalink.com.au>]

Patrick Norton wrote:
> 
> I feel as bit foolish posting this, but I can't find an answer anywhere.
> Generally, when a reptile is depicted with its mouth open (dino's included)
> a flap of skin is usually shown stretching between its upper and lower jaws
> near the joint. That membrane is present in extant reptiles, but what is it
> called? What is its purpose?

These are the jaw adductor muscles, that are used to close the jaws.


> 
> Is it possible that some dinosaurs exapted this membrane to serve as a type
> on non-muscular "cheek" (I'm thinking of the Ornithopoda  in particular)?
> 

Jaw adductor muscles seem to be connected to the inside of the
mandibles and skull. I suspect that ornithopod "cheeks" (if they
existed) would have been adapted from muscles or skin on the outside
of the jaws.

Disclaimer: I may have got all of this completely wrong, so don't
quote me!
-- 
____________________________________________________
        Dann Pigdon
        GIS Archaeologist
        Melbourne, Australia

        Australian Dinosaurs:
        http://www.geocities.com/capecanaveral/4459/
        http://www.alphalink.com.au/~dannj
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