Re: T Rex Poop Contents

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 08:37 PM 6/23/98 -0600, Richard Travsky wrote:
>The current issue of Science News (6/20) has a short article
>on the T rex coprolite.
>
>Now, I swear I read - either here or one of the web related
>articles - that the meal appeared to have been that of a young
>hadrosaur.
>
>The Science News article - quoting Gregory Erickson of U of Cal
>Berkeley and Karen Chin of the US Geo Survey, coauthors of the
>Nature article - states that the meal instead appears to contain
>the frill of a triceratops.

The authors themselves cannot determine for certain the identity of the
bones, but the press generally wants some kind of answere.  Here is what
Chin, Tokaryk, Erickson & Calk actually say in the paper:

"The absence of secondary osteons indicates that the bone was ontogentically
juvenile, so the ingested animal appears to have been a subadult dinosaur.
Although bone histology is not species-specific, the absence of arrested
growth lines may indicate an ornithischian dinosaur.  Lines of arrested
growth have been observed in several theropods but have not been observed in
the long bones of _Triceratops_ and _Edmontosaurus_ (G.M.E., unpublished
observation), the most common dinosaurs found in the Frenchman Formation.
Other ornithischians from the formation include _Torosaurus_,
_Thescelosaurus_ and an ankylosaur.
    The thickness of the cortical bone indicates that the fragments may be
derived from appendicular bone or ceratopsian frill."

(p. 681)

Hope this helps.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661