Is Brontosaurus Real? The Dinosaur Science Erased for 112 Years

PALEODEX · 15 July 2026 · 7 min read

People search "is Brontosaurus real" every day, and the honest answer is not yes or no. It was named in 1879, erased by science in 1903 by the same man who named Brachiosaurus, and argued back to life in 2015, in a comeback other paleontologists still don't fully accept.

Few dinosaurs have had a stranger paper trail than Brontosaurus. It was one of the first giant sauropods ever mounted for the public, it named an entire era of museum-going childhoods, and for more than a century it was, officially, not a real genus at all. Then in 2015 it came back. This is the real sequence of events, and the honest answer to whether "Brontosaurus" is a name you can still use.

The most famous dinosaur, named in 1879

In 1879, the paleontologist Othniel Charles Marsh described a huge sauropod skeleton dug up at Como Bluff, Wyoming, in the rock of the Morrison Formation. He named it Brontosaurus excelsus ("thunder lizard"). It was mounted, illustrated, and became one of the defining images of the age of dinosaurs, reproduced in paintings, museum halls, and children's books for generations.

One scientist, one year: Brachiosaurus is born, Brontosaurus is erased

Marsh had actually named a different sauropod, Apatosaurus, two years earlier, in 1877. In 1903, the paleontologist Elmer Riggs, in the same year he named the new genus Brachiosaurus, published a monograph arguing that Brontosaurus was not its own genus at all, but a specimen of Apatosaurus, and that the two supposedly distinct skeletons were really the same animal at different growth stages. Under the rules of zoological naming, the older published name has priority. Apatosaurus had been named first, so Brontosaurus excelsus became Apatosaurus excelsus, and the name "Brontosaurus" was, officially, suppressed. One scientist, one year: he created the giant everyone would come to love, and deleted the name everyone already did.

The wrong head

It gets worse. Marsh never had a skull for his Brontosaurus skeleton — sauropod skulls are small, delicate, and rarely preserved attached to the body, so he mounted one anyway, based on a skull found nearby (catalogued as USNM 5730). Decades later, paleontologists re-examined that skull and found it did not belong to Brontosaurus, or even to Apatosaurus: it is now referred to Brachiosaurus. For most of the 20th century, the most famous dinosaur on Earth was posed wearing a different genus's face.

Revived in 2015, but not everyone agrees

In 2015, Emanuel Tschopp, Octávio Mateus, and Roger Benson published the largest specimen-level study of diplodocid sauropods ever attempted: 477 morphological characters, scored across 81 specimens. Using a statistical threshold for how different two skeletons need to be to count as separate genera, they found that Brontosaurus and Apatosaurus differed enough to justify splitting them apart again. Brontosaurus was reinstated as a valid genus, 112 years after Riggs erased it.

It is not the end of the argument. Paleontologists including Michael D'Emic and Donald Prothero have pushed back, pointing out that the criteria used to draw the line between "same genus" and "different genus" are, to a degree, a judgment call, one that a differently designed analysis could redraw. Textbooks and museum labels are still catching up, and some working sauropod specialists are simply not convinced the split should stick.

So, is Brontosaurus real?

One popular claim, that Brontosaurus and Brachiosaurus never coexisted, is also false: both come from the same Morrison Formation, the same rock, the same window of the Late Jurassic, roughly 150 million years ago. They really did share a floodplain. But the bigger question (is the name "Brontosaurus" valid?) doesn't have a clean yes or no. The 2015 study makes a real, rigorous case for reinstating it. Other specialists have a real, rigorous case for doubting that case. The most accurate answer to "is Brontosaurus real" is that scientists are still arguing about it, and that argument is exactly what good science looks like from the inside.

Why this belongs in PaleoDex

The Brontosaurus story is not a hoax and not a myth: it is a case study in how taxonomy actually works: named, sunk, mis-skulled, and reinstated, all on the paper trail, with every step attributable to a real publication. That is the whole PaleoDex idea: the real record, with the receipts, warts and unresolved arguments included. Explore its Morrison Formation neighbors on Continental Drift, and read more oddities from the record.

Sources

Every fact above is drawn from the primary literature and standard references:

• Tschopp, E., Mateus, O., & Benson, R.B.J. (2015). "A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)." PeerJ 3:e857. The 2015 study that reinstated Brontosaurus, scoring 477 characters across 81 specimens. (peerj.com/articles/857)
• Wikipedia, "Brontosaurus": naming history, the 1903 synonymy, and the 2015 reinstatement.
• Wikipedia, "Brachiosaurus": Riggs's 1903 description and the Felch Quarry (USNM 5730) skull history.
• Natural History Museum, "Brontosaurus: reinstating a prehistoric icon": a museum overview of the 2015 resurrection.