RE: Thoughts on Tanycolagreus

[Tim Williams <twilliams_alpha@hotmail.com>]

Jaime Headden wrote:

>   Carpenter et al. describe the premaxilla as short and deep, and 
> comparing well enough with a premaxilla referred to *Stokesosaurus 
> clevelandi* that they referred the bone as a paratype of *T. topwilsoni* 
> (UUVP 7821), leaving *S. clevelandi* represented by ilia, an inschium, 
> caudal vertebrae, and a partial braincase.

I'm not 100% certain that any of these elements actually belong to a single 
taxon.  The ilium (type) and braincase both look tyrannosaurid-like, so it 
would make sense for them to belong in the same taxon.  However, none of the 
_Stokesosaurus_ elements were found associated.  Thus, there is no evidence 
that the caudals referred to _Stokesosaurus_ actually come from this 
species.  AFAIK they were referred to _Stokesosaurus_ somewhat arbitrarily.

>   Further data would arrive in the form of a more indepth analysis and 
> inclusion of *T. topwilsoni* into a cladistic analysis, such as Holtz' 
> latest monster, and the presence of two tyrannosauroids in the Morrison 
> Formation may argue that *S. clevelandi* and *T. topwilsoni* are synonyms, 
> yet the only comparable material so far are caudal vertebrae.

My copy of the new theropod volume is still in transit, so maybe this is 
covered, but... if the caudals of _Stokesosaurus_ do resemble those of 
_Tanycolagreus_, then maybe they actually belong to _Tanycolagreus_.  After 
all, this is what happened with the premaxilla.

Cheers

Tim