RE: OLD ORNITHOMIMOSAURS

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> David Marjanovic
>
> > Well, we honestly don't have any confirmed tyrannosauroids from
> the Middle
> > Jurassic (that is, nothing which has been demonstrated as closer to
> > tyrannosaurids than to all other named clades of theropod), and the
> > troodontid teeth are just teeth.
>
> I was speaking, er writing, of the infamous Iliosuchus...

Which is what I figured.  However, as I said: we don't have any confirmed
tyrannosauroids from the Middle Jurassic.

An aside: there are a LOT of good websites out there, many by people on this
list, which show just about every non-avian dinosaur genus placed on the
tree.  This must be taken with amazingly large chunks of salt!!  The vast
majority of genera have never been subjected to phylogenetic analysis: their
addition to a data run *might* result in their placement on the tree at the
indicated spot, or it could be elsewhere, or indeed the addition may cause a
realignment of other taxa previously included in previous studies.

So, as a general warning: unless you can find the original source study,
treat any big cladogram on the web (or elsewhere) as even more provisional
than a standard analysis.

> > Well, I agree that it isn't a Triassic ornithomimosaur, but
> Oliver Rauhut
> > has offered another alternative: that _Shuvosaurus_ is a
> specialized basal
> > theropod.
>
> Interesting... Where would it lie on a cladogram?

Well, an exceedingly interesting question, as Rauhut DID run it in his
(as-yet unpublished) analyses, which transformed the traditional members of
Ceratosauria into a paraphyletic series relative to Tetanurae (and even made
Coelophysoidea a paraphyletic series relative to the
abelisaur-_Elaphrosaurus_-_Ceratosaurus_-Tetanurae clade).  If memory
serves, _Shuvosaurus_ fell among or just "inside" the coelophysoid-grade
theropods.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796