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Re: upside down ankylosaurs

Weren't the Asiatic ankylosaurs found right side up?

From: "Ken Carpenter" <KCarpenter@dmns.org>
Reply-To: KCarpenter@dmns.org
To: <dinosaur@usc.edu>
CC: <kevinandlorrie@earthlink.net>
Subject: upside down ankylosaurs
Date: Thu, 31 Oct 2002 09:05:19 -0700

At my first SVP meeting in 1976, Dr. Ann Elk presented a landmark hypothesis about sauropod morphology. In the same vein, I have been stewing on why so many ankylosaur skeletons in North America are found upside down. Charles Sternberg (1970, Nat. Mus. Canad., Pub. Palaeon. 4:1-9) ventured the idea that a floating carcass would drift upside down because decomposition gases would expand the belly. Once the gases vented, the carcass would sink. I had accepted that idea, although I modified it because not all ankylosaurs are found in riverine sandstone. I have suggested that, like dead armadillos, bloating gases would force the legs apart, thereby causing the rotund body to flip the animal over (1984, Canad. J. Earth Sci. 21: 1491-1498.

After many years of diligent research, and monitoring the recent discussions (again!) on tyrannosaurs vs. hadrosaurs, I conclude that both Sternberg and I were wrong. I suspect what really happened was that roving bands of delinquent subadult tyrannosaurs were engaging in ankylosaur tipping at night.

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology &
Chief Preparator
Dept. of Earth Sciences
Denver Museum of Natural History
2001 Colorado Blvd.
Denver, CO 80205

Fax: (303)331-6492
email: KCarpenter@DMNS.org
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