Re: Rex Jaws

[chris brochu <cbrochu@fmppr.fmnh.org>]

Matthew BONNAN wrote:
> 
 In
> any case, the ability to snarl and move lips requires facial muscles
> in mammals, particularily the orbicularis oris (the ring-like muscle
> around your lips), the levator anguli oris, the depressor anguli oris,
> mentalis, etc.  These muscles arise from the platysma and other
> derived mammalian features. 


The only facial muscles seen in living archosaurs are the constrictors
around the crocodylian naris, which serve to keep water out of the
nasopharyngeal duct when the animal is submerged.  And we don't see an
increased number of mental foramina around the naris.  


chris



-- 
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Christopher A. Brochu
Department of Geology
Field Museum of Natural History
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Chicago, IL 60605

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