RE: Dromiceiomimus diagnosis request

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Hector Rivera Sylva
> Sent: Friday, June 24, 2005 10:27 AM
> To: dinosaur@usc.edu
> Subject: Dromiceiomimus diagnosis request
>
>
> Can someone help me to find the diagnosis of the ornithomimids Dromiceiomimus 
> and Ornithomimus on the web? Or someone
> have them on pdf?
>
Based on Makovicky, Kobayashi, and Currie's chapter in Dinosauria II, there is 
no differential diagnosis between these two, as they
are the same genus!

Ornithomimus as a genus is diagnosed by:
* metacarpal I longer than other metacarpals (present in type and referred 
specimen of Ornithomimus velox and in the O. edmontonicus
hypodigm).

They diagnosis Ornithomimus edmontonicus (which includes all specimens formerly 
in Dromiceiomius) by:
* bifid dorsal ramus of the quadratojugal for reception of the descending ramus 
of the squamosal
* well-defined incision of the caudal border of the quadratojugal for the 
quadrate foramen

And O. velox (primarily based on a referred specimen from the Kaiparowits Fm., 
and consequently problematic) by
* gently curved pubic shafts
* preportionately longer ungual of pedal digit II.

Should there be reason to seperate the genera, the former taxon would become 
the new combination Dromiceiomimus edmontonicus.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
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