PALAEONTOLOGISTS don鈥檛 get many chances to name new bones. Evolution uses the same bones over and over again, altering their shape and purpose but preserving their basic nature, so anatomists simply use the same old terms to describe them. A humerus is a humerus, whether it鈥檚 in a chicken wing, a walrus flipper, the massive front leg of a brachiosaurus or our own upper arm. A few animals evolve bones that look different enough to earn their own distinct name, like the thagomizer, the fearful-looking cluster of spikes on the end of a stegosaur鈥檚 tail.
The name comes from Gary Larson鈥檚 cartoon series, The Far Side, rather than some bygone anatomist. Dinosaurs and cavemen were among Larson鈥檚 favourite characters, and he often put both in the same frame, fully aware of the anachronism. In 1982, he drew a caveman 鈥減rofessor鈥� lecturing to a class, pointing to a drawing of the tail spikes of a stegosaur and saying, 鈥淣ow this end is called the thagomizer, after the late Thag Simmons,鈥� evidently a victim of a disagreement with a stegosaur.
鈥淭he name comes from Gary Larson鈥檚 cartoon series鈥�
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Ken Carpenter, a palaeontologist at the Denver Museum of Nature and Science, remembered the thagomizer some years later as he studied a well-preserved stegosaur. Palaeontologists had been debating the function of the tail spikes, and Carpenter found one of them had been broken and healed, indicating that the stegosaur had used it as a weapon. As a Far Side fan, Carpenter dubbed the spikes a thagomizer when he described the fossil at a meeting of the Society of Vertebrate Paleontology in 1993.
Palaeontologists are playful sorts, and the idea of the thagomizer was too good to pass up. Dan Chure gave the thagomizer label to stegosaur spikes at the Dinosaur National Monument in Utah. Then James Farlow of Indiana University-Purdue University in Fort Wayne made sure the term appeared when he edited The Complete Dinosaur. His co-editor, Mike Brett-Surman, added the label thagomizer when he updated the Smithsonian Institution鈥檚 stegosaur fossil display.
Carpenter has even turned his terminological talents to naming new dinosaur species. He tagged one early predator gojirasaurus after Gojira, the original Japanese name of the monster we know as Godzilla, because it was a giant for its time. He is not alone. Jenny Clack of Cambridge University gave the name Eucritta melanolimnetes to the fossil of an early salamander-like creature that had lived in a swamp, because it is Greek for 鈥淭he Creature from the Black Lagoon鈥�. Leigh Van Valen of the University of Chicago took the names of 20 fossil mammals from J. R. R. Tolkein鈥檚 books. A 4-metre-long fossil Australian snake was named Montypythonoides. Two insects have been named after Gary Larson, a louse called 鈥�Strigiphilus garylarsoni鈥� and a beetle named 鈥淕arylarsonus鈥�.
