Re: A New Hypothesis for the Origin of Flight?

["Jaime A. Headden" <qilongia@yahoo.com>]

Waylon Rowley (whte_rbt_obj@yahoo.com) wrote:

<What the protoavians were doing in the trees in the first place is
anyone's guess, but I'm betting that they were insectivores, as the
conical teeth and "pointy" skulls of Archaeopteryx suggests to me.>

  "Pointy" skulls are not neccessarily insectivoran; birds that are
adapted insectivores tend to have broader jaws, as do most animals that
feast upon these protein-sinks. This is evident in many anurans; birds
like *Aegotheles* (owlet-nightjar), nighthawks and frogmouths, swifts,
etc. (incidentally, all members of the strigiform+apodiform+caprimulgiform
clade). In mammals, whose skulls are not nearly as plastic, you have bats
and many non-simian primatomorphs, and the moles and smaller "insectivore"
taxa that have broad jaws as well, though insectivore specializations
occur in mammals most evidently in the teeth (many small, spaced and
interlocking cusps and cuspules, broadening of the premolar-molar base,
etc.). Triangularization of the cranium in amniotes appears to be an
advancement of the orbital region, rather than the oral cavity, and is
almost certainly an arboreal adaptation where three-dimensional perception
is required. Such cranial morphology in fish is just as evident, as well
as projection of the eye beyond the "cheek" and orbital rim in general,
permitting visualization in multiple directions at once. Chameleons only
enhance this condition.

  that's my two cents...

  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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