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Re: Oviraptorids as Parrots?



--- "Jaime A. Headden" <qilongia@yahoo.com> wrote:

> Jura (pristichampsus@yahoo.com) wrote:
> 
> <Schwimmer (2002) hypothesized that _Deinosuchus_
> acquired it's incredible bite
> force (18,000 N!) by originally specializing in
> turtle eating. The rear teeth
> are low and rounded. These are believed to be the
> main shell crushing tools.>
> 
>   There are quite a few alligatorids with low and
> rounded, or simply downright
> bulbous posterior teeth. Most alligatorids and
> crocodylids are opportunistic,
> and this may reveal ancestral features in the diet,
> but not neccessarily
> declare the _current_ dietary regime. Note that
> features may be exapted from an
> originally specialized function as well as be
> derived _for_ that function.

+++++++++++++++++++++++++++++++++++++++++++++++++

Extant alligatorids do maintain some rounded rear
teeth. Low and behold, these are also the only extant
crocodylians to show a dietary preference for turtles.


Morphologically, turtle eaters tend to show rounded,
separated and deeply rooted teeth. Whereas
molluscivores (the other major shell crushers) show
tightly spaced, flat and shallow rooted teeth.

Along with _Deinosuchus_, there were a few more
crocodyliformes that are believed to have been...er,
chelonivorous. _Phosphatosaurus, Brachychampsa_ and
_Albertochampsa_ also show turtle eating dentition.

Schwimmer also mentions a few more pieces evidence,
including the close association of various chelonian
species with _Deinosuchus_ and (perhaps most
compelling of all) the presence of fossilized turtle
shells showing various bite marks and puncture wounds.
Many of these wounds fit a _Deinosuchus_ tooth
remarkably well.

Indeed, Schwimmer hypothesized that east coast
_Deinosuchus_ exapted their extreme turtle crushing
jaw morphology to a diet of dinosaurs as they headed
out west. There are a few dinosaur bones that suggest
_Deinosuchus_ snacked on dinosaurs, at least, every
once in a while.

Jason

"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer

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