Tyrant horns (was Re: UTILITY OF CLADE NAMES_

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 04:28 AM 4/28/98 EDT, Dinogeorge wrote:
>In a message dated 98-04-28 02:46:56 EDT, jwoolf@erinet.com writes:
>
><< _Tyrannosaurus_ has brow horns, >>
>
>If this is true (and I've heard that the Larsons just discovered this in
>"Stan"), then it's another point of difference between _Jenghizkhan_, which
>has no brow horns, and _Tyrannosaurus_--and a point of similarity between
>_Tyrannosaurus_ and earlier tyrannosaurines such as _Gorgosaurus_,
>_Albertosaurus_, and _Daspletosaurus_.

The type of T. bataar DOES have postorbital rugosities, the same as most
(but not all) specimens of T. rex.  T. bataar and T. rex have very low
lacrimal prominences and a distinctive posterior angulation of the lacrimal.

I think the poster to the list is using "brow horns" for "postorbital rugosity".

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