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Re: Segnosauria! (really!)



James Close wrote:

<I'm not looking to rehash an old thread here.. according to the
archives, it was a topic of some debate. But I couldn't find the
"conclusion"..
 
Does Segnosauria still reside in Theropoda? and Is feet the only
qualifier for being a Theropod?> 

  The most parsimonious position found for Segnosauria (aka,
Therizinosauroidea, the correct name [but see below]) is Dinosauria.
In the book _the Dinosauria_ it is considered _sedis mutabilis_, or
"changing place" largely because of the mosaic of characters they
possess. Please, Greg Paul and Jack Conrad are better at arguing this
point than I, and their positions argue for two things: a non-theropod
condition for segnosaurs (Paul) and a polyphyletic position for
segnosaurs, where true therizinosaurs (which includes *Alxasaurus*)
are theropods and the others are somewhere between the ornithschian
and saurischians (Jack), or as Greg argued in '87 (?) in _JVP_,
segnosaurs may be more similar to prosauropods, and you've got to
admit, there's a whole lot of similarity in the jaw and foot. However,
many characters of the skull and postctrania (except the foot) are
similar to ornithomimosaurs and oviraptorosaurs, a position I've found
best advocated by Peter Buchholtz.

  Search back int he archives near the beginning of this year: Jack
posted the list of characters that segnosaurs have, and they pretty
much fell equally among the prosauropod and theropod groupings.

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