Re: Szechuanosaurus

[Dinogeorge@aol.com]

In a message dated 96-01-05 18:51:00 EST, pharrinj@PLU.edu writes:

>Ah, yes.  As I recall, the type species of _Albertosaurus_ was the 
>badly-preserved _A. sarcophagus_, correct?  However, Paul (1988) writes 
>that the type skull of _G./A. libratus_ is of the daspletosaur-like 
>morph, indicating that it is the more primitive, big-toothed form that 
>needs a new name.  As I have never seen the specimens personally, 
>however, I defer to those more in-the-know.  At any rate, either the 
>big-toothed form or the daspletosaur-like forms (the rest of _A. 
>libratus_, along with _A. arctunguis_--possibly referable to 
>_Dinotyrannus_?) need a new appellation.

Yes, well, _Daspletosaurus_ happens to be a large-maxillary-toothed
albertosaurinid (i.e., tyrannosaurine with well-developed lacrimal horn) as
well as _Gorgosaurus_. After reading the literature and examining the
figures, I concluded _Gorgosaurus_ was phyletically intermediate between
_Albertosaurus_ and _Daspletosaurus_ in relative size of maxillary teeth and
dentary tooth count. Other interpretations, such as Tom Carr's that there was
only one species of albertosaurinid with lots of random
individual/ontogenetic variation, remain possible, of course. _Dinotyrannus_
has no lacrimal horn and belongs with _Nanotyrannus_ and _Tyrannosaurus_ in
tribe Tyrannosaurini. As with tribe Albertosaurini, the three included genera
_may_ all(!) be ontogenetic variants, but of the genus _Tyrannosaurus_.