HOW TO NAME A DINOSAUR

Learn all about it-then coin a name of your own!

- STORY & PHOTOS BY JIM BRACE-THOMPSON

Tyrannosaurus rex, or "tyrant lizard king," is so named for its huge size and fearsome appearance. It's said to have reigned like a king over other dinos of its day.

For 15 years, the U.S. National Park Service has sponsored National Fossil Day (www.nps.gov/fossilday/). This year, it's on October 15. Let's join in celebrating fossils by exploring what goes into the seemingly simple task of naming them. And what better fossils than dinosaurs? Scientific names often seem long and weird, and impossible to pronounce. Where do they come from? And why are there two names, like Tyrannosaurus rex? Let's find out!

MAKING IT OFFICIAL

There are no stringent rules governing so-called common names; for instance, calling a critter a bull frog. But designating a formal scientific name is another matter altogether. Going back to 1895, we've had an International Commission on Zoological Nomenclature. Using the International Code of Zoological Nomenclature, they are the ultimate arbiters in establishing that a scientific name is valid for animals, both living and fossilized. (There's a separate commission and code for naming plants.) This effort goes back to 1735, when Swedish biologist Carl Linnaeus noted confusion and duplication in efforts to catalog Earth's creatures. So he devised binomial nomenclature, first used in his most famous work, Systema Naturae. This was the origin of the two-part genus and species system we use today. Both words are italicized, with the genus name capitalized.

ESTABLISHING A HOLOTYPE