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RE: O. grandis and the USNM?

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Nick Gardner
> George Olshevesky wrote-
> >
> >Hmm. Is this actually Ornithomimus grandis, or something different?
> I had heard that this taxon was referred to Albertosaurus, has something
> changed?  And this is at the USNM?

Okay, let's take this from the top:

The TYPE specimen of O. grandis was some tyrannosaurid material from the
Eagle Sandstone Formation (early Campanian).  It consisted of at least some
metatarsals, but possibly more material.  It was in the Yale collection, was
supposed to be sent to the USNM, but was apparently lost in transit.  The
Eagle Sandstone has not produced many dinosaur fossils, so we don't know
which (if any) of the known genera of tyrannosaurids were present there.
Its referral to "Albertosaurus" is not based on detailed study, but merely
the knee-jerk reaction of the past to place any "smaller" western North
American tyrannosaurid material into "Albertosaurus".

In his 1896 magnum opus Dinosaurs of North America, Marsh revealed that he
had two additional specimens of "O. grandis", one of which was much more
complete.  Both of these are still present in the USNM.  The more complete
one is from the Lance Formation, and is almost certainly Tyrannosaurus rex.
The second specimen is older, and possibly referrable to either
Albertosaurus, Gorgosaurus, or Daspletosaurus: when I get a chance I will
check it again.

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