Thagomizer
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The thagomizer, or tail spikes, is an arrangement of four to ten spikes on the tails of particular dinosaurs of the clade Stegosauria, of which Stegosaurus stenops is the most familiar. The tail arrangement is believed to have been a defensive weapon against predators.[1]
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[edit] Etymology
This Far Side cartoon is the source of the term "Thagomizer".
The term "thagomizer" was coined by Gary Larson in a 1982 Far Side comic strip, in which a group of cavemen in a faux-modern lecture hall are taught by their caveman professor that the spikes were named "after the late Thag Simmons". The term was picked up initially by Ken Carpenter, a palaeontologist at the Denver Museum of Nature and Science, who used the term when describing a fossil at the Society of Vertebrate Paleontology Annual Meeting in 1993.[2]
Thagomizer has since been adopted as an informal anatomical term,[3] appearing, for example, on the website of the Smithsonian Institution.[4] The term has been used in displays at Dinosaur National Monument in Utah, in the book The Complete Dinosaur, and in the stegosaur display at the Smithsonian Institution.[2]
The fate of Thag Simmons notwithstanding, stegosaurs and humans did not exist in the same era. In The Prehistory of the Far Side, Gary Larson suggests that "there should be cartoon confessionals where we could go and say things like, 'Father, I have sinned – I have drawn dinosaurs and hominids together in the same cartoon.'"[5]
[edit] Paleobiology
There has been debate about whether the thagomizer was used for display only, as posited by Gilmore in 1914,[6] or used as a weapon. Robert Bakker noted the tail was likely to have been much more flexible than those of other dinosaurs as it lacked ossified tendons, thus lending credence to the idea of the tail as a weapon. He also observed that Stegosaurus could have maneuvered its rear easily by keeping its large hindlimbs stationary and pushing off with its very powerfully muscled but short forelimbs, allowing it to swivel deftly to deal with attack.[7]
More recently, a study of tail spikes, by McWhinney et al.,[8] showed a high incidence of trauma-related damage. This supports the theory that the spikes were used in combat.
Stegosaurus stenops had four dermal spikes, each about 60-90 cm (2 to 3 feet) long. Discoveries of articulated stegosaur armor show that, at least in some species, these spikes protruded horizontally from the tail, not vertically as is often depicted. Initially, Marsh described S. armatus as having eight spikes in its tail, unlike S. stenops. However, recent research re-examined this and concluded this species also had four.[9][10]
[edit] See also
[edit] Other scientific terms first used in comedy
[edit] References
- ^ Holtz, T.R., (2000) "Classification and Evolution of the Dinosaur Groups" (pp140-168) in The Scientific American Book of Dinosaurs, edited by Gregory S. Paul, New York: St Martin's Press ISBN 0-312-26226-4
- ^ a b The word: Thagomizer New Scientist 8 July 2006
- ^ Holtz, Thomas R., Jr. (2007). Dinosaurs:the Most Complete, Up-To-Date Encyclopedia for Dinosaur Lovers of All Ages. New York: Random House. p. 230. ISBN 978-0-375-82419-7.
- ^ [Archive copy at the Internet Archive "Stegosaurus Changes"]. Smithsonian National Museum of Natural History, Department of Paleobiology. Archive copy at the Internet Archive. Retrieved on 2007-03-03.
- ^ Larson, G. (1992) The Prehistory of the Far Side p. 137. Warner Books.
- ^ Gilmore CW (1914). "Osteology of the armored Dinosauria in the United States National Museum, with special reference to the genus Stegosaurus". Series: Smithsonian Institution. United States National Museum. Bulletin 89 (Government Printing Office, Washington) (89).
- ^ Bakker RT (1986). The Dinosaur Heresies. william Morrow, New York.
- ^ McWhinney LA, Rothschild BM & Carpenter K (2001). "Posttraumatic Chronic Osteomyelitis in Stegosaurus dermal spikes". in Carpenter, Kenneth(ed). The Armored Dinosaurs. Indiana University Press. pp. 141–156. ISBN 0-253-33964-2.
- ^ Marsh OC (1877). "A new order of extinct Reptilia (Stegosauria) from the Jurassic of the Rocky Mountains". American Journal of Science 3 (14): 513–514.
- ^ Carpenter K & Galton PM (2001). "Othniel Charles Marsh and the Eight-Spiked Stegosaurus". in Carpenter, Kenneth(ed). The Armored Dinosaurs. Indiana University Press. pp. 76–102. ISBN 0-253-33964-2.
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