Re: Sauropod necks????

[Phil Bigelow <bigelowp@juno.com>]

On Sat, 21 May 2005 11:57:17 -0700 (PDT) don ohmes <d_ohmes@yahoo.com>
writes:

> That said, if there is no coprolitic material
> conceivably attributable to sauropods that contains
> large quantities of (ground by gizzard stone?) mollusc
> shell, then I don't think it is very robust. 

Even if sauropods ate mollusks, sauropod coprolites might not contain any
trace of the shells.  Stomach acid can be pretty brutal on calcium
carbonate.

And there is no evidence that sauropods yacked up pellets, so that is a
dead end.

On the other hand, analysis of stomach contents may prove to be a
fruitful avenue of study.  If the animal died soon after it had dined,
then traces of shell material may be interspersed with the gizzard
stones.  The shell traces may not be easy to spot.  They may be sand-size
or smaller, etched, and mixed with the matrix.  Unless paleo field crews
are specifically interested in analyzing the microconstituents of
sauropod gizzards, this matrix will probably wind up being discarded
during field excavation and lab preparation.

Another avenue of study would involve the analysis of isotopic ratios in
sauropod bones.  if the isotopic ratios of nitrogen and carbon in mollusk
meat are different from the ratios found in terrestrial protein sources,
then it may provide some clues.  That is, assuming the above assumption
is true. (a comparative study of the isotopic ratios in sea otter bones
vs. ursid bones would be useful).

Regardless if some/all sauropods ate mollusks, it is clear that a major
portion of their diet was plant material.  Sauropod jaws and teeth are
perfectly designed to strip vegetation, involving little or no chewing. 
Mollusks may have only supplemented their diet.


<pb>
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