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Re: POLYPHYLY IN THERIZINOSAURS



In a message dated 98-02-27 02:08:14 EST, Tetanurae@aol.com writes:

<< As for what therizinosaurs are related to, my best guess is that they are
the
 sister group to ornithomimosaurs within the Bullatosauria because of the
down-
 turned dentary, similar teeth, similar mandibular complex and pneumatic
 parasphenoid. >>

As I've posted numerous times, it's not the parasphenoid but the BASISPHENOID
that is pneumatic in segnosaurs. Segnosaurs do NOT have the bullatosaur
inflated parasphenoid seen in troodontids and ornithomimids, and their palatal
complex is quite different from the bullatosaur palatal complex. Although the
parasphenoid and basisphenoid are fused in segnosaurs, this doesn't mean
they're COINCIDENT: one is at the FRONT of the braincase, the other at the
BACK.