Brontosaurus

Brontosaurus is a genus of sauropod dinosaurs that lived during the Late Jurassic period, about 150 million years ago, in what is now western North America. The name, meaning “thunder lizard” in Greek, was assigned to the type species Brontosaurus excelsus. Its fossils have been found primarily in the Morrison Formation, a rich assemblage of dinosaur remains.

The genus was introduced by Othniel Charles Marsh in 1879. For much of the 20th century, Brontosaurus was considered a junior synonym of Apatosaurus, and the name fell out of common use. In 2015, a study argued that Brontosaurus should be recognized as a distinct genus from Apatosaurus, reinstating Brontosaurus in the scientific literature. Since then, the status has remained debated, and some researchers continue to treat Brontosaurus as a synonym of Apatosaurus or to advocate cautious, case-by-case classification. Museums and public sources differ in how they present the fossils, reflecting ongoing taxonomic discussion.

Physically, Brontosaurus was a large, long-necked, quadrupedal herbivore. It possessed a very long tail, a relatively small skull, and a massive body supported by four sturdy legs. Estimates for length generally place individuals in the range of about 15 to 25 meters (roughly 50 to 80 feet), with body masses in the tens of tons. Its teeth were small and peg-like, adapted for stripping vegetation rather to grinding. Brontosaurus, like other sauropods, likely fed on high-growing vegetation and played a significant role in its ecosystem.