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Re: upside down ankylosaurs
Weren't the Asiatic ankylosaurs found right side up?
From: "Ken Carpenter" <KCarpenter@dmns.org>
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 &
Dept. of Earth Sciences
Denver Museum of Natural History
2001 Colorado Blvd.
Denver, CO 80205
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