Thanks to fossil discoveries from as early as the mid-1800s, over a thousand dinosaur species have been identified to date. But of all the extinct reptiles documented, most people are probably only familiar with those found in popular culture — including the tyrannosaurus, brontosaurus, stegosaurus, and triceratops.
It may therefore come as a surprise to many that the brontosaurus was actually revoked of its name in 1903. The re-designation occurred when scientists realized that the species had been previously documented under a different name, apatosaurus, at an earlier point in time.
Recently, researchers have suggested that stegosaurus may face a similar fate. In an article published in the Swiss Journal of Geosciences, Peter Galton of Yale University indicated a potential discrepancy between the designation of “stegosaurus” and the species of dinosaurs they represent.
But while news sources have been abuzz with talk of stegosaurus’s demise in the nomenclature system, the reality is far less substantial. In his original article, Professor Galton proposes that the “type species” of the stegosaurus — which is currently based on the Stegosaurus stenops model — should be delegated to a more complete version of another existing fossil, the Stegosaurus armatus. This means that the stegosaurus name will not be removed, but rather, that the term be re-designated to a more accurate model of the fossilized creature.
Dr. David Evans, the associate curator for the Royal Ontario Museum and an assistant professor at the University of Toronto, compares this change in nomenclature to our original designation for birds as being creatures with feathers. This designation was later redefined when reptiles — namely dinosaurs — were also found to have sported feathers.
“Many new species are initially defined by fragmented [incomplete] fossils, but over time, it can be shown that these original defining features may actually be much more widely distributed among a broader class of species,” says Evans.
The classification of species, known as taxonomy, is often an overly detailed examination of morphological and genetic characteristics and a re-designation such as this is not entirely uncommon.
Professor Galton states that he plans to approach the International Code of Zoological Nomenclature — the agency that regulates the naming of animals — to rectify the designation of stegosaurus with the Stegosaurus armatus type species.
The stegosaurus situation contrasts with that of the brontosaurus, in which the ICZN was forced to rename the entire species based on previous fossilization records. But regardless of the ICZN’s final conclusions, the name “brontosaurus” has survived the test of time and continues to be used regularly in everything from children’s books to newspapers.
So even if stegosaurus had met the same fate as its troubled cousin, would this change really travel outside of the academic community, where these fine details seem to matter most? Not very likely.
