The thunder lizard that vanished and returned: why Brontosaurus is finally back

Nature · Published 3 October 2026 Swipe more like this →

In short: For decades, the iconic Brontosaurus was dismissed as a scientific error, subsumed into the genus Apatosaurus. Despite its disappearance from formal taxonomy, the name persisted in public imagination. A landmark 2015 study finally vindicated the thunder lizard, proving that its physical differences were distinct enough to warrant its own genus.

The story of the Brontosaurus began in 1879 when American paleontologist Othniel Charles Marsh described the genus after discovering a nearly complete skeleton at Como Bluff, Wyoming. The name, derived from the Greek for thunder lizard, quickly captured the public imagination. By 1905, the American Museum of Natural History became the first institution to mount a reconstruction of the sauropod, cementing its status as an icon of the prehistoric world.

However, the dinosaur's scientific standing collapsed in 1903. Paleontologist Elmer Riggs concluded that the Brontosaurus specimen was merely a younger version of Apatosaurus, a genus described two years earlier. Under taxonomic naming rules, Apatosaurus became the official classification, and Brontosaurus was relegated to a synonym. This confusion was compounded by a lack of a skull; early reconstructions used a conjectural head based on the unrelated Camarasaurus, an error that persisted in museums and textbooks for decades.

The tide turned in 2015 when paleontologist Emanuel Tschopp and his colleagues conducted the largest phylogenetic analysis of sauropods to date. By examining 477 physical features across 81 individual specimens, they determined that the morphological differences between Brontosaurus and Apatosaurus were significant enough to separate them into two distinct genera. This study reinstated Brontosaurus as a valid genus, specifically for the species B. excelsus.

While the classification controversy is settled for many, it remains a point of nuance in paleontology, with some experts still debating the split. Today, we know the Brontosaurus was a quadrupedal herbivore that lived during the Late Jurassic. Unlike the earlier, inaccurate reconstructions, modern understanding highlights its robust build and distinct anatomy, finally separating the thunder lizard from its long-time shadow, the Apatosaurus.

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