Inner Children Rejoice: There Is Probably a Brontosaurus After All!
A thorough sorting of the Diplodocidae clade brings science's most famous misnomer back into use.
Brontosaurus artistic reconstruction. Image: Davide Bonadonna, Creative Commons license CC- BY NC SA
Pluto may never be a planet again, but people who think scientific reclassifications are ruining their childhoods have one less thing to complain about: the name Brontosaurus has come back from extinction and proposed as a genus distinct from Apatosaurus, which had, for 112 years, claimed the scientific name, but never the public's heart.
A new study in the open-access journal PeerJ applied a thorough, statistical analysis to the Brontosaurus branch of the Diplodocidae family tree and emerged with a cladogram where Apatasaurus and Brontosaurus are separate, if close, relatives.
For a while there, it was weird that we knew the name "brontosaurus" at all. The first brontosaurus fossil was discovered just two years after the first apatosaurus, which meant that, in 1903, when scientists determined that the brontosaurus specimen was a young apatosaurus, its genus name was supposed to die and Brontosaurus excelsus was supposed to, instead, be known as the Apatosaurus excelsus. But the name "brontosaurus" lived.
Even as new discoveries changed how the public thought the dinosaurs lived—moving them out of the swamps and onto dry land—the name remained.
According to Matt Lamanna, a curator at the Carnegie Museum of Natural History in Pittsburgh, "brontosaurus" is just too good of a word to die: "Brontosaurus means 'thunder lizard,'" he told NPR. "It's a big, evocative name, whereas Apatosaurus means 'deceptive lizard.' It's quite a bit more boring."
But researchers from the United Kingdom and Portugal dug into the entire Diplodocidae clade, the branch of the tree of life where the brontosaurus, apatosaurus, and lower-slung diplodocus had been placed. The researchers then performed a "specimen-based phylogenetic analysis" on "all holotype specimens of every putative diplodocid species yet described," the study states.
Collected from four continents, the mostly-Jurassic-era specimens were scored for 477 morphological characteristics, making it one of the most extensive phylogenetic analyses of sauropods ever. The researchers then looked at 81 operational taxonomic units, 49 of which belong to Diplodocidae, and used the others for contrast.
In the resulting sorting, the brontosaurus reemerged, or so the authors propose. We'll see if the classification sticks under further review, as taxonomic changes don't necessarily happen overnight and generally require a consensus of researchers to take effect. Still, the new study argues that Bronotosaurus excelus is indeed a distinct species, and that individuals in the Elosaurus and Eobrontosaurus genera should join Brontosaurus under the names B. yahnahpin and B. parvus.
"The differences we found between Brontosaurus and Apatosaurus were at least as numerous as the ones between other closely related genera, and much more than what you normally find between species," Roger Benson, a co-author from the University of Oxford, said in a press release.
Science is an ongoing project, and dinosaur taxonomy is no exception. One day the brontosaurus is just a young apatosaurus, and the triceratops and torosaurus are two separate species and there are nine planets. Today, the apatosaurus and the brontosaurus are separate species, the torosaurus was revealed to be a mature triceratops, and we're down to eight planets, all of which is subject to change depending on what new data is uncovered.