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Black Market T. rex (was CD-ROM)



> I'm surprised that nobody offered any comments on my report of black-market
>T.rex pieces. Is it a taboo subject? Does everybody have a piece of the "rock"
>except me?  :)

I wish! :-)  I didn't answer because I was mystified by some of the bizarre
statements from the original posting:

>The picture shows a
>white streak of bone(?) about two fingers wide in a piece of rock about 30 cm
>long. It is described as "a deep, rusty brown color and appears to have a
>marrow-like appearance on either end. The interior of the fossil, which is ex-
>posed on one side, has crystals growing in the cavity." "Apparently, Tyranno-
>saurus bones were quite different from other prehistoric creatures. They were
>honey-combed, not solid. They were also less dense than those of other carniv-
>orous dinosaurs.

First off, there is some confusion over what color the bone is, white (very
unlikely) or "a deep, rusty brown color" (much more likely).

The crystals growing in the cavity (chemically deposited after burial)
don't have the ring at all of a Cretaceous bone (sounds more like the bad
parts of the  Morrison).  However, I haven't seen much in the way of the
Frenchman fossils before, so maybe...  However, Tyrannosaurus bones are NOT
different from other prehistoic creatures, and are not honey-combed
(although the long bones of a T. rex, as with all theropods, are hollow).

There is no evidence that Tyrannosaurus bones are less dense than those of
other theropods (as I can vouch from personal experience).  In fact, it is
damn difficult to distinguish a complete bone of Tyrannosaurus rex from
other big tyrannosaurids (most of the difference is in the skull, and in
various body proportions.  T. rex is bigger than any other North American
tyrannosaurid, but it would be hard to tell the size of the whole animal
from an apparently nondescript fragment of longbone.

So, by the morphology of it, there doesn't seem to be anything that
indicates T. rex rather than another big theropod.  However, the bone seems
to have come from the Frenchman Formation, which is the proper age (late
Maastrichtian stage, Lancian North American Land Mammal "Age" [actually,
it's an "Assemblage Biozone", not an "Age"]) and seems to be a theropod
(since it is described as being hollow).  Tyrannosaurus rex is the only
really big theropod known from Lancian deposits (although it doesn't sound
big enough to prohibit it from being from Nanotyrannus or a big
ornithomimid, both of which come from the same age and region).

So, he may indeed have a black market Tyrannosaurus rex.
                                     
Thomas R. Holtz, Jr.
Vertebrate Paleontologist in Exile
U.S. Geological Survey
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092

email:  tholtz@geochange.er.usgs.gov 
Phone:  703-648-5280
FAX:            703-648-5420