RE: Daspletosaurus temporal/stratigraphic range

[henry mendoza <hxmendoza@yahoo.com>]

--- "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
wrote:
> > From: owner-dinosaur@usc.edu
> [mailto:owner-dinosaur@usc.edu]On Behalf Of
> > Tim Donovan
> >
> > Is Daspletosaurus known exclusively from Campanian
> units, or is there
> > evidence of it in the Horseshoe Canyon or
> equivalents?
> 
> At present, Campanian only.  See Carr and Williamson
> (2000, NM Mus. Nat.
> Hist. & Sci. Bulletin 17: 113-145) for a review of
> the southern part of the
> range.  Some consider CMN 11315 from the Horseshoe
> Canyon a posssible
> Daspletosaurus, but I have seen no evidence in that
> specimen that it is
> anything other than Albertosaurus.
> 
> > What is
> > the age of a
> > daspletosaur reported to resemble Tyrannosaurus
> more than others?
> 
> If by this you mean the Two Medicine specimen
> briefly described by Horner et
> al. (which, in fact, may simply be Daspletosaurus
> torosus, or it could be a
> new species of D.), it is late Campanian.
> 
> > Is there
> > any possibility that TMM 41436-1 represents a
> Daspletosaurus?
> 
> Possible, yes.  Any evidence pointing to it being a
> Daspletosaurus rather
> than a juvie T. rex, no.
> 
>               Thomas R. Holtz, Jr.
>               Vertebrate Paleontologist
> Department of Geology         Director, Earth, Life & Time
> Program
> University of Maryland                College Park Scholars
>               College Park, MD  20742
> http://www.geol.umd.edu/~tholtz/tholtz.htm
> 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
> 

Hey Dr. Holtz,

What is he current status of the genus Gorgosaurus.
Carr continued to lump it in with Albertosaurus,
apparently just accepting Russell's analysis, but not
really elaborating on why. Yet, I have heard
hints/comments throughout the last few years from
Currie and you that it is distinct from Albertosaurus.

While we are at it. Any comments on the
Tarbosaurus/Tyrannosaurus generic problem too? I
believe them to be congeneric yet distinct species
(bataar, rex) I keep reading G. Olschevsky's reasoning
for maintaining Tarbo but it doesn't fly with me. No
disrespect to George though, I just don't agree with
him. As an example, I don't see any real difference
between the "pendant" nature of the postorbital bar
that intrudes into the orbit. There is SO MUCH
variation in all the T.rex skull, including that area,
that I see no real differences than can be accounted
for by other than species dinstinctiveness. Tooth
count does not fly with me either. Again, I believe it
only a species distinction. 

My only concern morphologically would be the odd
looking scapulocoracoid of one of the Tarbo skeletons.
Namely the larger of the two skeletons displayed in
the Great Russian Dinosaur Exhibit. The coracoid looks
very different from any tyrannosaurid specimens I have
seen. I figured it was just a restoration error. As it
is obvious in the illustrations of the russian
monograph that the coracoid was incomplete (but then
why not restore it like all the others?). Any comments
on that?

Regards,

Henry Mendoza

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