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Re: Torvosaurus



At 02:12 AM 2/15/98 PST, Jaime A. Headden wrote:
>
>Can anyone tell me if they agree that the similarity of *Torvosaurus'* 
>and *Cryolophosaurus'* lachrymals means that Torvo can be included in 
>the Carnosauria as on the same cladistic branch of *Cryolophosaurus* and 
>basal Allosauroidea?

Could be, but what does the weight of the evidence say?  Single character
resemblances are interesting, but one must figure out a) are the
resemblances derived or primitive and b) what is the distribution of other
features in the anatomy.

The skull of Cryolophosaurus is pretty puzzling as currently described,
particularly the squamosal-postorbital-jugal contact (which, in all
right-thinking theropods, do NOT form a single contact in the middle of the
infratemporal fenestra!!).  I haven't seen the postcranial material, so
that's (obviously) more difficult to judge...

In most recent studies, true carnosaurs (Allosauroidea and closely related
forms) are more closely related to coelurosaurs than either group is to
Torvosaurus.  Carnosaurs and coelurosaurs share a maxillary fenestra,
pneumatic lacrimals, and other features not known in Torvosaurus.  However,
it is possible that later studies might reveal features uniting allosauroids
and Torvosaurus within Carnosauria.  Such is the way of phylogenetic
analysis (or any science, for that matter: subject to revision based on new
data).

I think that Bakker et al.'s and Sereno's suggestion that Eustreptospondylus
is closely related to Torvosaurus may have some merit based on current data.
Unfortunately, both are less complete than one (okay, I) would like... :-(

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