RE: Thoughts on Tanycolagreus

[Ken.Carpenter@dmns.org]

(after much head banging on the wall)

What we noted regarding Tany is that is most closest to Coelurus of all
theropods. Much of the speculation by individuals about the placement of
Tany as basal tyrannosaurid, etc., are based on no knowledge of what the
skull of Coelurus is like; I predict it will also have a deep max. There
is an erroneous assumption that deep max is a restricted character of
tyrannosaurids. However, I would challenge this. It does APPEAR that way
on a skull viewed in profile, but only because the bone is
foreshortened. Look at JUST the premax in profile (meaning viewed
oblique to the skull) and the body  of the premax is significantly
longer relative to height than in Tany. 

Nothing was said in our paper about the referred caudals of
Stokesosaurus. All of the material of Tany was found together (as the
quarry map shows), thus there is no doubt of their association.

The height of the acromion of Coelurus is unknown because it is missing
(see p. 60 of The Carnivorous Dinosaurs), thus to state that Tany is
closer to tyrannosaurids, whereas Coelurus is not is totally
unwarranted. 

I could go on, but this is enough for a start.

Ken

Kenneth Carpenter, Ph.D. 
Curator of Lower Vertebrate Paleontology 
and Chief Preparator 
Department of Earth Sciences 
Denver Museum of Nature & Science 
2001 Colorado Blvd. 
Denver, CO 80205 USA

Ken.Carpenter@DMNS.org
ph: 303-370-6392/ or 6403 
fx: 303-331-6492 

for PDFs of my reprints, info about the Cedar Mtn. Project, etc. see:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
for fun, see also:
http://dino.lm.com/artists/display.php?name=Kcarpenter

 

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] 
> On Behalf Of Thomas R. Holtz, Jr.
> Sent: Tuesday, July 12, 2005 7:36 AM
> To: qilongia@yahoo.com; dinosaur@usc.edu
> Subject: RE: Thoughts on Tanycolagreus
> 
> > From: owner-dinosaur@usc.edu 
> [mailto:owner-dinosaur@usc.edu]On Behalf 
> > Of Jaime A. Headden
> >
> 
> [lots of stuff snipped!]
> 
> > Nonetheless, the similarities
> > between *T. topwilsoni* and *D. paradoxus* are unmistakable and 
> > provide the following hypothesis:
> >
> >   *Tanycolagreus topwilsoni* is the most basal member of 
> > Tyrannosauroidea, and provides the most complete skeletal 
> evidence for 
> > Tyrannosauroidea in the Upper Jurassic, affirming *Aviatyrannis 
> > jurassica* and *S. clevelandi* as tyrannosauroids.
> >
> >   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.
> >
> I haven't included it yet, but planned on including it for 
> the Rockford Jane symposium. However, my impressions run 
> pretty close to yours, and I wouldn't be terribly surprised 
> if it isn't a basal tyrannosauroid.
> 
> Incidentally, it is decent sized animal: Carpenter et al. 
> estimate the Cleveland-Lloyd individual at about 3.5 m long.
>