Sauropod stones

["Norton, Patrick" <Patrick.Norton@state.me.us>]

On June 4th, Darren Naish wrote:

>Well, as I understand it, Gillette says that sauropods stored stones
in two places - in their crop (located at base of neck) and in their
gizzard. Apparently the taphonomy of _Seismosaurus_ shows that the
stones burst from both locations during decomposition.<

"snip"

>It has been implied that the 'choking' stone was found in the crop or   
cranial to it.<

I think there are at least 3 equally likely explanations for the   
"choking" stone that do not require the novel explanation that stones   
were stored in the crop of sauropods (assuming they even had a crop.)

1) The stone actually was ingested by the Seismosaur, stuck in its throat   
and choked it to death.  I think this is the least likely scenario, for a   
number of reasons. For one, the esophagus of living animals with gizzards   
(which this creature apparently had) is typically remarkably   
elastic--particularly in animals that consume large, rough or irregular   
food. An exception to this is the graminivorous birds, which usually have   
a narrower and less elastic esophagus. Given the likely food sources of   
the Seismosaurs, I would expect it to have a wide and very elastic   
esophagus;

2) The stone was never ingested and was simply in the proximity of the   
animal by random chance. Techniques such as Darren mentioined (analysis   
by light scattering)--that can apparently discriminate between biological   
and geological causes of abrasion--would be very useful in answering this   
question; or

3) The stone was a gizzard stone that was displaced after death.