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Re: Another Alxasaurus query (was: thanks and ...)
At 06:44 AM 2/2/99 -0800, you wrote:
>---"Jaime A. Headden" <email@example.com> wrote:
>> Okay, I am operating on the assumption that segnosaurs are
>Aren't they considered to be?
>With all due respect to George (and I don't mean that sarcastically),
>is there real controversy among dinosaur paleontologists about the
>assignment of these dinosaurs ("therizinosaurs"/"segnosaurs")?
>If so, has anyone published a critique of the Russell/Dong analysis in
>a (all together now) peer-reviewed scientific journal?
In a sense: a few papers currently out or in press reexamine the Russell &
Dong analyses (and additional data). See Sues 1997 paper on _Chirostenotes_
(JVP 17:698-716) and Makovicky & Sues's _Microvenator_ paper in Am. Museum
Novitates for two explicit data matrices already published.
Now, to be fair, none of these studies currently *published* test what is
needed to refute Olshevsky's assertion: namely an analysis where
prosauropods and/or ornithischians are also included among the ingroups, so
that (in terms of the search mechanics) recovery of a
prosauropod-therizinosauorid clade is at least possible.
>The fourth toe is awfully odd, isn't it?
I assume you mean the first toe. Both Russell & Currie have both suggested
(at least in talks) that we are looking at it the wrong way: digit I isn't
lenghtened, the rest of the metatarsus is shortened. Yes, ad hoc and all
that, but given the rest of the character distribution that seems to be one
>Is there an analogy that can be drawn in, say, extant mammals?
Good question. I'll see if someone else can call one up (i.e., a reduced
digit which recontacts the epipodial-metapodial joint and also recontacts
I agree with George on therizinosauroids about one thing, though: it is
damned hard to make them the sister taxon to ornithomimosaurs (when so many
other maniraptoriforms share more features with them).
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:firstname.lastname@example.org
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661