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Re: Segnosaurs



><<SEGNOSAURS! Are they really still categorized as theropods? If so, why? As
>far as I know, the only reason for that is that they have sharp claws and
>teeth, and that seems kind of rediculous. I'm sure all you who think they are
>theropods  have some good, scientific reason for it, I'd just like to hear
>what it is. >>
>
>Well, people think that segnosaurs are theropods rest everything on a newly
>discovered segnosaur called _Alxasaurus_ that they claim has a semi-lunate
>carpal in the wrist, thus making it a maniraptor.  I have seen the type
>specimen of _Alxasaurus_ and believe me, it DOES NOT have a semi-lunate
>carpal block; the wrist bones DO NOT look like the ones drawn in the paper!
> They are to me a sister taxon to Predentata, which with segnosaurs makes
>Ornithischia.  Some have also tried to make people use this god-awful name
>for them: Therizinosauroidea instead of Segnosauria.  DON'T USE IT (sorry
>Tom)!

Yeah, bite me :-)

The semilunate carpal is easily seen in the hands of Late K Mongolian
therizinosaurs (see Maleev 1976).  The skull of Erlicosaurus is clearly
theropodan. Those who do not want therizinosauroids as theropods have yet to
present a detailed data matrix of derived characters to support their
statement.  They reject the possibility of reversals in the feet of the
therizinosauroids.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084