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

Re: Eating a Nautilus (attn: Gothgrrl)



At 07:48 PM 11/17/97 +0000, you wrote:
><HTML>
>I visited Tyrrell Museum a week or so ago and while there, I spoke with
>Dr. Paul Johnston. He is studying ammonite shells with holes in them that
>were supposedly made by mosasaur teeth. He suggests that some of the holes
>may not have been made by mosasaur bites. The evidence is very interesting.
>Some of that evidence comes from an experiment they did using a mechanical
>device that simulates the bite of a mosasaur. They used it on modern nautilus
>shells and compared the resulting damage to fossil specimens. The holes
>made by the device created different patterns of damage than is seen in
>the fossils. He suspects that other reasons, such as limpets, could have
>been responsible for making some of the holes.
><BR>Regards,
><BR>Shane Leuck
><BR>--
><BR>The Gateway Country Fossil Page
><BR><A
HREF="http://www.tst-medhat.com/~s.leuck";>http://www.tst-medhat.com/~s.leuck</A>
>
><P>Daniel Varner wrote:
><BLOCKQUOTE TYPE=CITE>At 10:38 PM 11/15/97 +0000, you wrote:
><BR>>Just slightly off topic for a change.
><BR>>
><BR>>Did Mosasaurs and Pliosaurs eat nautiloids whole?&nbsp; Did they crack
>them
><BR>>open with their jaws?&nbsp; Did stomach muscles crush the shells?&nbsp;
>Does the
><BR>>fossil record help with these questions?
><BR>>
><BR>>Thanks,
><BR>>Larry<A HREF="http://www.hotmail.com";></A>
>
><P>Dear Larry, I can't answer your question as far as Pliosaurs are concerned.
><BR>I am not aware of any ammonite shells with bite marks that can be
attribited
><BR>to those plesiosaurs. Remember that the shells are made of calcium
>carbonate
><BR>and are easily dissolved by the stomach acids.
><BR>&nbsp;The mosasaurs are another matter, however. Their bites are
conspicuous
>on
><BR>numerous specimens of ammonites, indicating that the animal was removed
>from
><BR>the shell. Prognathodon is a prime suspect when it comes to this behavior.
>A
><BR>new specimen is nearing completion in the prep stages at the South
>Dakota
><BR>School of Mines and Technology. The skull is massive with very robust
>teeth.
><BR>The European species, Prognathodon solvayi, has very protrusive teeth
>in the
><BR>premax that seem to be perfectly formed as an escargot fork.
><BR>&nbsp;Globidens, of course, is the mosasaurian bivalve-eater (we think).
>Another
><BR>SDSMT specimen may have stomach contents,so stay tuned. Interestingly,
><BR>Prognathodon and Globidens are very closely related. See Gorden Bell's
><BR>article in Nicholl's and Callaway's _Ancient Marine Reptile_
volume.</BLOCKQUOTE>
></HTML>
>
>I am sure many creatures were drilling, boring, and otherwise mutilating
whatever came to rest on the Cretaceous sea floor. I am at a loss, however,
how limpets could figure out how to create holes on ammonite shells that
replicate mosasaur dentitions and skull shapes then multiply those same
patterns over and over and over again from various angles on an ammonite
shell. If you haven't read it, see _Kauffman,E.G.and Kesling,R.V.1960, An
Upper Cretaceous Ammonite bitten by a mosasaur. Contributions of the Museum
of Paleontology. Univ.of Michigan, 15 (9), 193-248._ This is a classic paper.
 Dan Varner