[snipped]
Do Tinker's teeth rule out the Nano
question? Well, consider this. While Tinker may have had different teeth as a
baby, as a 60% adult sized juvenile he had the same teeth as Mom and Dad.
Tinker is the same size as an adult Nano. Adult Nanos have totally different
teeth than Tinker. This would certainly be a strong indicator that Nanos are
NOT T.rexes.
"Tinker is the same size as an adult Nano". An
interesting comment, given that our one and only specimen has juvenile bone
texture! Regardless of whether or not _Nanotyrannus_ is a juvenile _T.
rex_ or not, the only known skull of _Nanotyrannus_ is of a juvenile. If
it is a distinct taxon, we do not know its adult
size.
Also, a warning concerning so-called "adult Nano"
teeth: we DO have evidence of another Lancian
tyrannosaurid, distinct from the _Nanotyrannus_/_T. rex_ morphology,
with _Nanotyrannus_-like blade-like teeth: _"Aublysodon" (or _Stygivenator_)
molnari_. Until someone can find a way to distinguish between isolated
teeth of these two taxa, it is best not to assign such isolated maxillary or
dentary teeth to one or the other taxon.
Also, I read a description of the Nano skull that
mentioned that the snout was sharper, more 'foxlike' and that Nano's eyes may
have been set for forward on the face giving better binocular vision than a
T.rex.
From what I understand of Tinker's skull remains,
they are classic T.rex in shape."(Snipped)
As
Carr discusses in his recent JVP article, there are some major shape changes
in skulls of growing tyrannosaurids (just as there are in other dinosaurs: no
surprise there). Until such time that a _T. rex_ juvenile the same size
as (or smaller than) but distinct in form from the type of _Nanotyrannus_ is
discovered, or an adult _Nanotyrannus_ distinct in form from _T. rex_, this
matter will be a matter of debate.
So,
sorry for those who want the answer RIGHT NOW: it simply isn't available
yet.
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