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Re: "Fighting specimen" GI 100/25



At 01:37 PM 12/17/96 -0500, T.A. Curtis wrote:

>     A comment on GI 100/25.
>     Is it generally accepted that this is an example of interspecific
>combat?  I mean, is it _really_ accepted that these two critters just
>_happened_  to be locked in a death struggle when they were perfectly
>entombed for fossilization?
>     Sure, it's possible. . .But the odds on fossilization (and discovery)
>are already lower than low; _this_ strains credulity.  Isn't there any
>other explanation?

Dave Unwin can speak to the specifics.  Post-mortem association was
suggested by some of the Polish and Mongolian workers, but the Unwin et al.
study refutes most of the earlier conclusions.

There are plenty of other fossils in the Djadochta Formation and equivalents
which demonstrate VERY rapid burial (e.g., Protoceratops specimens caught in
mid-struggle while digging their way up out of sand).  Only in unusual
settings can you get behavioral preservation like this, but the sands of the
Djadochta seem to have been pretty nasty at times.  Similar burials are
known to occur in sandy deserts today.

Spectacular preservation DOES happen (i.e., limulids at the end of a "death
march" trail in the Solnhofen; entombed rhinoceratoids preserved vertically
in ash layers, etc.), but, as you note, it is VERY rare.

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

"To trace that life in its manifold changes through past ages to the present
is a ... difficult task, but one from which modern science does not shrink.
In this wide field, every earnest effort will meet with some degree of
success; every year will add new and important facts; and every generation
will bring to light some law, in accordance with which ancient life has been
changed into life as we see it around us to-day."
        --O.C. Marsh, Vice Presidential Address, AAAS, August 30, 1877