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Re: Theropods and dewlaps



Stephen Pickering (StephanPickering@cs.com) wrote:

<As noted in this forum during the past year, evidence exists some
theropod taxa possessed dewlaps. Probably the best study I have seen on
dewlaps is:

Enrique F. Font, 1988. Functional morphology and central control of 
dewlap extension in the displays of Anolis equestris (Sauria, Iguanidae).
Ph.D. dissertation, Univ. Tennessee, 102pp.>

  This may be of some functional use to animals with extensible dewlaps,
as those in anolids are controlled by the hyomandibular skeleton and
musculature. Theropod ceratobranchials are much shorter and robust, and
would not have acted in such a fashion. My own research in the works of
Aerts, Herrell, and de Vree have yielded substantial results on the matter
of the hyomandibular structure in various reptiles and that of some birds
by Burton (including psittaciforms), and mosty variation is affected in
the tongue strcture. Instead, dewlap anatomy and function is best
dissassociated from the hyomandibular skeleton as associated with merely
the neck skin and cutaneous musculature, as in zebu (Bovini, Bovidae,
Ruminantia). There does not seem to be a latitudinal variation in
expression, as water buffalo lack this flap, but are in hotter climes, and
many Southeast-Asian taxa have it...

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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