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Re: Removing segnosaurs from ...



<<>1) A relatively large premaxillary (compaired to theropods).
>2) Elongate vomers.

Also typical of theropods.>>

The theropods that you are claiming that segnosaurs evolved from however, all
have tiny vomers.  You can't tell me that the oviraptors that you claim have
a sister relationship with the segnosaurs don't have some of the smallest
vomers ever encountered.  And, quite obviously, segnosaur premaxillaries are
gigantic, while theropods' are small.

<<>3) Elongate nares.
>4) Deep narial shelf.
>5) Deeply recessed anteorbital fossa and fenestra.

Actually, this is a VERY theropod (or at least avetheropodan) character.>>

Funny, this is from the list of characters that Barsbold and Osmolska put in
"The Dinosauria" linking prosauropods with segnosaurs.  I would very much
like you to find me a theropod that has as large nares as _Erlikosaurus_.

<<>7) General tooth structure.

Same tooth structure in troodontids, and similar to those of toothed
ornithomimosaurs.>>

Are you saying that Troodonts have no teeth in the fronts of their jaws?  You
yourself agree that segnosaurs are herbivorous, how can you claim that their
teeth are identical to Troodonts?

<<>17) Lack of the maniraptoran "pulley-action" elbow-wrist complex 
>   (i.e. the arms don't fold like birds').

Actually, as per the Russian lit listed above, the hands of
therizinosauroids DO have a very nice semilunate carpal pulley structure,
and probably could fold their hands inward.>>

I have a photograph in my hands of the type specimen of _Alxasaurus'_ wrist.
 For two and a half weeks I have not been able to find the "semi-lunate"
carpal from the photograph just as I could not see it when I saw it in person
in Vancouver.  Would you please be so kind as to tell me where it is?  As far
as I am concerned, it is not there.

I cannot see any characters linking theropods to segnosaurs.  The semi-lunate
carpal block is not there, the tetradactyl pes is identicle to prosauropods,
and the head and jaws show no great affinities to theropods.

Peter Buchholz
Stang1996@aol.com