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Tyrannosaurids (was Re: )



At 02:16 AM 12/19/97 PST, you wrote:
>I need some input from all you guys (and gals) on the list.

>2.
>*Tyrannosaurus* is distinct from Asia to North America, one of our 
>Asiamericanan dinosaurs. There is sufficient difference between the dead 
>(no pun intended) *Tarbosaurus efremovi* and his senior synonym *T. 
>bataar* to *Tyrannosaurus rex* that I feel we have a single species on 
>our hands, but two subspecies, *Tyrannosaurus rex rex* and *T. r. 
>bataar,* the last synonymizing *Tarbosaurus,* *Jenghizkhan,* and 
>*Maleevosaurus* as age-particular individuals. This I feel is a much 
>safer (and more scientifically based) dinstinction to make than any 
>other I've seen on the subject, and I don't recall ever seeing it 
>discussed on the list before.

Hmmmm... Perhaps you could check the archives, say under my name?  Also, you
may wish to check out George Olshevsky's post for an alterantive view.

Also, sometime in the new year, check out the Tree of Life webpages for more
on the subject... :-)

>*Albertosaurus* represents a genus with a subspecies, as well. Instead 
>of assigning new genera to the several species now accepted under the 
>name of this tyrant, a better approach would be to subspeciate a few of 
>them, and group them accordingly. So, 1.) *Albertosaurus sarcophagus* 
>should stand alone, pending more complete material to work with

Which is present, and distinct from Gorgosaurus.

>2.) *A. libratus* is sufficiently complete and distinct to base a 
>species on, not to rename it *Albertogorgon* or resurrect *Gorgosaurus* 
>for it.

Based on...?  Alternatively, on what basis would you GROUP Albertosaurus
with Gorgosaurus?

>Should I go into the groupings of *Aublysodon,* who is based on a tooth 
>and is therefore a nomen dubium? I will state that I don't think 
>*Alectrosaurus* is a shanshanosaurid (aublysodontid), as based on 
>characters that separate Alectro from Shanshan.

And you have seen either the Alectrosaurus and Shanshanosaurus material
where?  The restorations of the latter, for example, are inaccurate (except
those of Tracy Ford!), based on observations of the specimen or its photos.

>*Triceratops* posed me a major headache about three years ago when I 
>picked up Glut's second version of the _Dinosaur Dictionary_ and I began 
>to set up a character map for all those species, which have now been 
>placed in two species, with one turned into a new genus.

Hmmm... Perhaps you might wish to read the work of Catherine Forster, rather
than simply look at Glut's book.

I'm not saying that you are wrong in these matters.  However, it looks as if
you have not delved into the actual taxonomic literature on the subject.

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