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Re: Limusaurus Inextricabilis



--- On Sun, 6/21/09, Augusto Haro <augustoharo@gmail.com> wrote:

> From: Augusto Haro <augustoharo@gmail.com>
> Subject: Re: Limusaurus Inextricabilis
> To: david.marjanovic@gmx.at
> Cc: "DML" <dinosaur@usc.edu>
> Date: Sunday, June 21, 2009, 11:28 AM
> 2009/6/20 David Marjanovic <david.marjanovic@gmx.at>:
> >> I suppose gastroliths may be useful to crush a
> rat-sized prey in an
> >> alligator-sized predator
> >
> > ...but that's not what happens. The alligator that was
> filmed was in fact
> > fed a dead rat with stones sewed into it. As the film
> shows, the rat was
> > digested, and the stones just lay around and did
> nothing.
> 
> Ok., so apparently there is no evidence for carnivorous
> archosaurs
> (although to be fair, the fact that new films indicate the
> stones do
> not crush a rat do not invalidate Bakker's 1986
> observations of the
> contrary -and would mean that both things can happen,
> perhaps under
> different conditions not considered-, unless we hypothesize
> technical
> inferiority for Bakker's means of observations).
> 
+++++++++++++++++++++++++++++++++++++

Adding more to the confusion is this paper:

Fitch-Snyder, H. and Lance, V.A. 1993. Behavioral Observations of Lithophagy in 
Captive Juvenile Alligators. J. Herp. 27(3):335-337

The authors observed juvenile _A.mississippiensis_ purposefully ingesting 
stones right after being fed. The authors point out that free stones are rare 
in alligator habitats, and that digestion appears not to go any faster with the 
stones. 

The consensus of Fitch-Snyder and Lance, was that the function of gastroliths 
in crocodylians remains a mystery, but since lithophagy occurred right after 
feeding, it actually might be an evolutionary hold over from when the animals 
used to use rocks to help digest prey.

Oh, and to help make things even muddier. Lithophagy is also known in a variety 
of other reptiles too.

Jason