RE: Tyrannosaur stuff

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Tim Williams
>
> Ken Carpenter wrote:
>
> >It may very well be that Tany was previously named, so offer your evidence.
>
> Currently there is no evidence - I got nuttin'.  There is no reason to
> believe that there was not more than one Morrison tyrannosauroid: Tany and
> Stokesy.  In fact, there may have been several tyrannosauroids scooting
> around North America during the Late Jurassic, especially if (a) the
> tyrannosaurid/itemirid-like braincase from CLDQ that was (provisionally)
> referred to _Stokesosaurus_ represents a new taxon; and/or (b) the
> _Stokesosaurus_-like ilium from South Dakota comes from another taxon (maybe
> _Aviatyrannis_).  I was just reiterating the possibility that
> _Tanycolagreus_ and _Stokesosaurus_ *might* be the same (which,
> incidentally, would give a very decent skeleton); I was in no way endorsing
> the suggestion.

Indeed. I alluded to this fact.  However, I would add that while the damaged 
premaxillary teeth of _Tanycolagreus_ look more
typically tetanurine in form, there are much more tyrannosauroid-like 
incisiform premaxillary teeth known from Como Bluff (and which
closely resemble those of Guimarota). So there might well be at least two basal 
tyrannosauroids in the Morrison.

> This is interesting, given that there is currently no evidence that the
> small-bodied tyrannosauroids survived into the Late Cretaceous (unless
> _Itemirus_ is a tyrannosauroid - and even this critter lived much earlier
> than the big-ass tyrannosaurids of the Campano-Maastrichtian).

Well, if _Bagarataan_ is a tyrannosauroid...

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> T. Michael Keesey
{responding to the same questio)
>
> I'm not sure where the cut-off between "small-bodied" and "big-ass"
> is, but _Alectrosaurus olseni_, _Alioramus remotus_, and _Dryptosaurus
> aquilunguis_ were smaller than any tyrannosaurines, and not terribly
> larger than EK tyrannosauroids. (Errr, unless _A. olseni_ or _A.
> remotus_ are tyrannosaurine ... what is the latest on that?)

Nearly all evidence points to _Alioramus_ as a tyrannosaurine, but exactly 
where among them remains unresolved.

[Back to Tim Williams]

>  Late
> Cretaceous dromaeosaurs, by contrast, came in all sizes.

Not so much. At least, not so much in North America, at least: no real sign of 
Achillobator-sized raptors in the land of rex and
torosus.

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
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