[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

So many tyrannosaur questions, so little time



Greetings,

I am horrendously bogged down with work right now, but there are a bunch of
recent points I wanted to make concerning the recent discussions of
tyrannosaurs and hadrosaurs and such:

1) Stokesosaurus comes out as a primitive tyrannosauroid (below Eotyrannus)
in recent soon-to-be published analyses by various workers, even when the
braincase is not considered.

2) PLEASE do not confuse news reports about recovery of specimens with the
detailed surveys of specimens found in the field!!!!  Finding T. rex is
newsworthy; sadly, finding ornithischians are not.  Consequently the former
get preferentially reported.
        A detailed survey of specimens recovered from the Hell Creek is not, to 
my
knowledge, published yet.  Therefore any statement about relative abundances
of T. rex, Triceratops, Edmontosaurus, Anatotitan, and the like is pure
speculation.

3) Ceratopsid mummies are also known: it is not a uniquely hadrosaurid
phenomena.  Consequently, do not use the existence of duckbill mummies as
evidence of superskin.  Why are hadromummies more common?  Perhaps hadros
were more common in the particular habitats favoring skin impressions.
Needs further study.

4) By and large, all tyrannosaurids are the same postcranially.  With a few
exceptions (neck length of tyrannosaurines, arm length of Tarbosaurus, etc.)
they are simply the same body.  Differences in their proportions are nearly
all allometric, so that a Daspletosaurus-sized T. rex has a
Daspletosaurus-shaped body, etc.  Thus any hypothesis you erect concerning
intra"familial" differences in Tyrannosauridae should NOT require different
postcranial adaptations.

5) A Tyrannosaurus trackWAY?!  Please, please, please state your reference!
To my knowledge, none is in the present literature!!

6) Throughout the discussion, remind yourself: is your hypothesis something
that can be preserved in the bones or in the sediment?  If so, has their
been a study to test it (or can you think of how such study would be
organized)?
        If, on the other hand, it is not something that can be preserved in 
bones
or the sediment, are there any *reasonable* ways that you could test the
idea?  If not, then you are dealing in the realm of unconstrained
speculation, and should not expect others to accept your idea
preferentially.

Hope this helps,

                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): 301-405-0796