Re: Ornitholestes

["Mickey_Mortimer11" <Mickey_Mortimer11@email.msn.com>]

Jordan Mallon wrote-

> What, then, does he say about _Proceratosaurus_, who is also believed to
> have had some type of nasal horn?  If the two were so closely related (and
> it would certainly seem so by looking at the rest of the skull), why would
> one have a horn (or crest) and not the other?  (Seems like the answer
might
> be obvious, but I have a hard time accepting the idea that two apparently
> closely-related forms would have differed so significantly in such a
> feature.  _Dilophosaurus wetherilli_ and _D. breedorum_ aside.)

Tim supplied great answers for the various parts of this thread, but for
this question I think an obvious response has not been given- because the
presence of a cranial crest would be derived, so not necessarily expected of
all ornitholestiids.  Sort of like asking why all oviraptorids don't have
Ingenia's odd manual morphology.

Tim Williams wrote-

> No cladistic analysis
> (AFAIK) has found support for such a clade - at least not recently.

The only analyses using both Ornitholestes and Proceratosaurus I know of
are-
Rauhut (2000) placed Proceratosaurus basal to Coelurus, compsognathids and
tyrannosauroids, with Ornitholestes above these yet below maniraptoriformes.
Holtz (2000) placed Proceratosaurus down by Gasosaurus and Dryptosaurus,
with Ornitholestes the next closest to birds (Coelurus, Scipionyx and
Bagaraatan were higher still, with compsognathids as maniraptorans).
Holtz reports that Proceratosaurus comes out sister to Ornotholestes in some
of his Ostrom Symposium trees though.
Holtz's newest (SVP 2001) phylogeny has Ornitholestes and Proceratosaurus in
a polytomy with compsognathids, Nedcolbertia and Nqwebasaurus, with
Scipionyx more basal.  Tyrannosauroids, Coelurus and maniraptoriformes are
higher.
I haven't added Proceratosaurus to my analysis yet, as I want a good
illustration and description of the material first.

Mickey Mortimer