In the world of fossils, not every name lasts forever

LOS ANGELES -- Along with a state bird, butterfly, fish and tree, California boasts its own fossil, Smilodon californicus, or Californian saber-tooth cat.

Problem is, there was no such species.

Rather, there was once such an animal, skeletons of which have been found by the hundreds at the La Brea Tar Pits. But the name of the species was tossed out by scientists in the 1980s in favor of Smilodon fatalis.

For decades before then, paleontologists had attached the names to what they thought were two distinct species. They now believe they were one.

"The scientific name has changed, but it's still the same animal," said John Harris, chief curator of the Natural History Museum of Los Angeles County's George C. Page Museum of La Brea Discoveries.

While the name S. californicus remains enshrined in California law -- and, for the time being, on exhibit labels at the Tar Pits museum -- it is considered an invalid name in paleontological databases of fossil North American mammal species.

Countless more bad names lurk within those databases, which tally the currently used names of the roughly 3,300 species of mammals known to have lived over the past 146 million years.

A single species can bear multiple names: S. fatalis has had as many as six. And sometimes multiple species are fixed with a single name. In other cases, the remains of female and male examples of a creature can be mistakenly dubbed as separate species.

Living or dead

The problem is hardly rare, or even unique to extinct mammals. The brontosaurus, for one, is properly known as the apatosaurus by dinosaur experts. Nor are the living exempt: The taxonomy of living insects is notoriously muddled.

But fossil remains can be particularly vexing, as not every species is preserved in the fossil record. When remains are found, they can be so fragmentary that scientists often have little more than a single tooth on which to base the identification of a new species.

As a consequence, the name game is in constant flux.

"We all know taxonomy is a work in progress, as all science is, and nobody thinks they know the final truth," said Scott Wing, a research paleobiologist at the Smithsonian Institution's National Museum of Natural History.

The naming errors have crept in, slowly and surely, ever since Sweden's Carl Linnaeus began the modern system of classifying living things in the 1730s.

"Taxonomists aren't gods, they're people, so that's the way it goes," said John Alroy, a researcher at the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara.