News Bite: Brontosaurus revived!
Brontosaurus was an extinct name for an extinct animal, but a new study brings the “Thunder Lizard” title roaring back to life! But how does a name get dropped, and how does it get brought back again? Follow us into the winding world of paleontology taxonomy, the study of names.
In the 1870s two giant hip bones were found and named by one of the great paleontologists of the age: Othniel Marsh. He thought there were a few differences and called one Apatosaurus ajax and the other, named a few years later, Brontosaurus excelsus.
The Brontosaurus and Apatosaurus parts of those names are the genus, and the second part – excelsus and ajax – are the species. In 1903 another paleontologist, Elmer Riggs, decided they weren’t different enough to be different genera. Apatosaurs was the older genus, so Brontosaurus excelsus became Apatosaurus excelsus to show other scientists how closely related it was to Apatosaurus ajax. They were two species in the same genus.
Infographic created by 4.0 PeerJ
A new study looked at every specimen from the family that includes Apatosaurus that has ever been collected: Diplodocidae. The family Diplodocidae includes long-necked dinosaurs with horse-like faces and whip-like tails. Some of the specimens were collected 150 years ago but were never really scrutinized before.
In the new analysis, the specimens once called Brontosaurus were found to be related to different specimens from Apatosaurus ajax. They aren’t each other’s closest relatives anymore, so the name Brotosaurus was brought back to describe this newly discovered cluster of specimens that are united by newly discovered anatomical features such as Brontosaurus’s narrower neck.
This is just one more hypothesis for dinosaur relationships. There are more fossils to discover in the field and in museum collections and paleontologists will keep hunting for more relatives of the Thunder lizard and its kin!
Emanuel Tschopp, Octávio Mateus, and Roger B.J. Benson. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3:e857 https://dx.doi.org/10.7717/peerj.857