Re: Albertosaurus/Gorgosaurus (Re: Re: allosaur furcula)

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

At 06:33 PM 6/7/97 -0700, DinosØMP wrote:
>Thomas R. Holtz, Jr. wrote:
>> (And, before someone asks the question again: YES, Gorgosaurus does seem to
>> be a valid taxon, distinct from Albertosaurus, on both gradistic and
>> cladistic grounds).

>OK. Now I'm getting confused....

The short form: Anytime you see a skeleton or picture of "Albertosaurus"
libratus, it is really Gorgosaurus libratus.

On the very, very rare occasion (outside of Canada) that you see a skeleton
or picture of Albertosaurus sarcophagus (or A. arcunguis, if it is indeed
different), it is really Albertosaurus.

We know a LOT more about Gorgosaurus, since there are a lot more fossils of it.

The shorter form: Chances are, when you see something labelled
"Albertosaurus", it is really Gorgosaurus.

>If anyone does have the book The 
>Illustrated Encyclopedia of Dinosaurs, bu Dr. David Norman. In the 
>tyrannosaurid pages-the drawing of a juvenile Albertosaur,

That particular drawing is NOT based on any real specimens (more's the
pity), but is an extrapolation of what a small Gorgosaurus libratus would
look like.

>and the photo 
>of a Albertosaurus eating a ceratopid...Is it REALLY albertosaurus???

I'm not sure of the particular specimen (for example, if that skull really
came with that body: a long-standing problem with dinosaur mounts), but it
looks to be Gorgosaurus libratus.

>And there is allso a skeleton of a "Gorgosaurus" laying in a dried 
>position-lacking the tail (I think it is at the Smithsonian Institute) is 
>that REALLY Gorgosaurus?

That one is Gorgosaurus, yes.  (And it is a Smithsonian specimen).

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