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Gastroliths and Lung Ventilation
>Crocs do carry gastroliths, and not just for ballast! Radiographic
>in the 1970s showed that they aid in the digestion of meat (break up
>bones in things like rats).
Croc gastroliths are in the posterior portion of the body cavity, a
result of the vertical division associated with the hepatic-piston
diaphragmatic lung ventilation system. Now bird gastroliths and gizzards
are more anterior ( see where I'm going?). Now then we have a putative
theropod dinosaur, Protarchaeopteryx, with gastroliths in the body
cavity: does anyone with better pictures of the thing than me tell
whether the gastroliths are anterior or posterior? Because _if_
Protarchaeopteryx is a theropod and _if_ the gastroliths are anterior
then the claims that all theropods had a hepatic-piston do not apply for
at least one group of non-avian dinosaurs.
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