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Re: pneumatic bones

Rob Gay wrote-

> If only I had my monograph with me here on break! From what I remember,
> Welles lists pleurocoels being present in the dorsals, and unless I don't
> really know what a pleurocoel is (quite possible), then I've seen at least
> dorsal with at least 1 pleurocoel from a specimen of _Dilophosaurus_.

Well, first we have to recognize "pectorals 2-5" of Welles (1984) are
homologous to dorsals 1-4 of other theropods.  They will be referred to as
dorsals in this message.  Welles states single pleurocoels are present in
the first four dorsals, but the fourth is shallow.  A lateral depression is
said to be found on the fifth.  The first dorsal does actually have a small
pleurocoel in the lateral depression.  Both the text and figures indicate
the other dorsals merely have lateral depressions without the aperture into
the central cavity that distinguishes a true pleurocoel however.  So you are
correct, I revise my previous listing to indicate the first dorsal (eleventh
presacral) of Dilophosaurus has a single pair of pleurocoels.  I was
apparently misled by both the referral of anterior dorsals as pectoral
vertebrae and the figure of the first dorsal that does not show the small
pleurocoel in the depression.

Mickey Mortimer