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RE: tooth question




        -----Original Message-----
        From:   Thomas R. Holtz, Jr. [SMTP:th81@umail.umd.edu]
        Sent:   Tuesday, January 26, 1999 7:39 AM
        To:     Dwight.Stewart@VLSI.com
        Cc:     dinosaur@usc.edu
        Subject:        RE: tooth question


        >       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
        >
        >       I'd love to get Dr. Holtz's take on Nanotyrannus!  :-)

        Funny you should mention that, because that is a concern in one of
the five
        papers that have topmost code ultra priority right now. (%-S)

        As I said at SVP 97, Nanotyrannus and Maleevosaurus come out (based
on
        character analyses) as the serial outgroups to T. rex + T. bataar.
So, the
        characters that unite the big forms COULD be phylogenetically
significant,
        or they COULD simply be the adult features lacking in Nano. &
Maleevo.

        Regardless of its position, it is *CLEARLY* juvenile: the bone
texture is
        very 'ropey', characteristic of animals still in the fast growing
stages of
        life.  The question then becomes: is it a juvie T. rex, or a juvie
something
        new.
        @@@@@@@@@@@@@@@@@@@@@@@@@@

        Thanks!  Which made me think of another question: Dr. Horner states
that there is evidence for a fast growth rate in Tyrannosaurus rex up to the
age of 4-5
        years (sorry, not sure about the exact number of years) and that
after the
        specimen neared or attained adult status, the growth rate altered.
He states that this implies that the animal may have changed metabolism
strategy after a
        certain time/age.  Do you agree and if so, what about other
Tyrannosaur
        species, such as bataar?  Is their evidence of the same or a similar
growrth pattern with them?

        @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
        >What were
        >the results of the CAT scans (MRIs... whatever) that Dr. Bakker had
        >performed
        >       on the Nanotyrannus skull?  I recall the report of this
being done,
        >but not the results.

        Never published.  New scans are planned.
        @@@@@@@@@@@@@@@@@@@@@

        Great!
        @@@@@@@@@@@@@@@@@@@@@@

        >Is Robert Bakker still convinced this is a distinct
        >species of Tyrannosaur, as opposed to a juvenile Tyrannosaurus rex?

        Yes.
        @@@@@@@@@@@@@@@@@@@@@@@@@
        Okay. :-)  Thanks!
        Dwight
        @@@@@@@@@@@@@@@@@@@@

        Thomas R. Holtz, Jr.
        Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
        Dept. of Geology              Email:tholtz@geol.umd.edu
        University of Maryland        Phone:301-405-4084
        College Park, MD  20742       Fax:  301-314-9661