Re: New Theropods

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

Peter Buchholz writes:

>Hi everyone.  I've got a couple of questions about some newly
>discovered theropods (hence the title).  I just got the new National
>Geographic the other day.  It's very interesting, I like it better
>than the egg one.  I have a question about Sereno's new theropod
>called _Deltadromeus_.  He says it is a Coelurosaur (in the proper
>sense), but not what kind.  Does anyone know what of Coelurosaur it
>is?  Is it possible that it is related to Baryonichids, Spinosaurids,
>Irritatorids or Troodontids?  I would think that that might be a

Those first three are all really the same clade.  Lack of serrations
on teeth which are otherwise indistinguishable does not rank (;-) up
there as justifying a new family, in my humble opinion.

Deltadromeus seems to be more like Ornitholestes or Dryptosaurus than
any of those others you mention.  And, of course, there is no stong
evidence for the coelurosaurian, much less bullatosaurian, nature of
the spinosaurs.

Sereno et omnia place it closer to "other coelurosaurs" than to
Ornitholestes. (A parenthetical comment: Why aren't my fellow theropod
systemicists including Compsognathus in their cladograms?  It's not
exactly a poorly known or poorly described taxon, and there are some
excellent casts (e.g., the Yale Peabody cast) in North America!).

>somewhat valid line of inquiry since, three of the four groups are
>known from northern Africa and or southern Europe.  Also, I must now
>admit publicly that I believe Segnosaurs (I will not say the Th word)

Why not?  It has priority.

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

"There are some who call me...  Tim."