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Re: titanosaurs

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Somphospondyli is united by the namegiving spongy vertebrae the
distribution  of which has been miscoded by Wilson & Sereno, according to
Wedel's big Acta> Pal. Pol. paper on *Sauroposeidon* ... >

  There are, however, more supportive features relating *Euhelopus* to
titanosaurs, aside from the name-giving feature (which is still generally
apomorphic in the increasing smaller and more complex camellate structure
of the vertebrae and progressive invagination of the vertebrae by these
camellae), but I was actually referring to the nature of the form as a
titanosauriform (i.e., including *Brachiosaurus*) including the structure
of the arm, shoulder, cervicals, etc. In these, *Euhelopus* qualifies as a
titanosaur relative of some close association and worth consideration
above the structure of a "Euhelopodidae" that has been supported by more
generally plesiomorphic features that are typically only absent in
diplodocimorphs or titanosaurs proper, relegating the unity to
symplesiomorphy and less likely to be truly autapomorphic than my broad
face and large eyes being a special autapomorphy with tarsiers than with
the apes. What seems more tenable is a Mamenchisauridae of which
*Shunosaurus* may be a basal member of or the sister group to
Mamenchisaurus and other sauropods, exclusive of *Euhelopus*.


Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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