Thagomizer

A cartoon of a group of cavemen. One points at a diagram of a dinosaur's tail with four spikes. The caption reads, "Now, this end is called the thagomizer...after the late Thag Simmons."
This Far Side cartoon is the source of the term thagomizer.
Best evidence for the use of the thagomizer is this Allosaurus tail (caudal) vertebra showing a punctured process. The hole perfectly matches a thagomizer spike.[1]

A thagomizer (/ˈθæɡəmaɪzər/) is the distinctive arrangement of four spikes on the tails of stegosaurian dinosaurs. These spikes are believed to have been a defensive measure against predators.[2][1]

The arrangement of spikes originally had no distinct name. Cartoonist Gary Larson invented the name "thagomizer" in 1982 as a joke in his comic strip The Far Side, and it was gradually adopted as an informal term sometimes used within scientific circles, research, and education.

A thagomizer on the tail of a Stegosaurus fossil
  1. ^ a b Carpenter, K., Sanders, F., McWhinney, L., and Wood, L. 2005. Evidence for predator-prey relationships: Example for Allosaurus and Stegosaurus. Pp. 325-350 in Carpenter, K. (ed.) The Carnivorous Dinosaurs. Indiana University Press, Bloomington.
  2. ^ Holtz, T. R., (2000) "Classification and Evolution of the Dinosaur Groups" (pp. 140–168) in The Scientific American Book of Dinosaurs, edited by Gregory S. Paul, New York: St Martin's Press ISBN 0-312-26226-4.