RE: tyrannosaurid ancestry, raptors and other fun things...

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> T. Mike Keesey
>
> > Mike ,
> > What is the oldest , unambiguous tyrannosauroid found to date ? My
> > references are not clear on this issue . Thanks in advance .
>
> Seeing as all the non-tyrannosaurid tyrannosauroids are ambiguous, that
> would have to be _Alectrosaurus_, from the Turonian(?).

Well, _Alectrosaurus_ is the oldest NAMED tyrannosaurid.

However, Cenomanian-aged tyrannosaurid teeth are known from the Mussentuchit
Member of the Cedar Mountain Formation, and from Aptian-Albian deposits of
Japan.  These show definite tyrannosaurid characters, unlike some of the
semi-tyrannosauriform teeth (e.g., the Gumiarota teeth) which occur earlier.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-314-7843