Stomping across the Jurassic floodplains, the Apatosaurus was a massive sauropod dinosaur over 75 feet long and weighing more than 20 tons. With its long neck and whip-like tail, it was a tremendous sight that towered over the smaller dinosaurs of its day.

The Apatosaurus is especially unique in paleontology due to its history of discovery. Originally, the dinosaur was mistakenly mounted with other sauropod skulls. It wasn't until nearly 30 years after the first discovery that an Apatosaurus skull was found and identified.

The Apatosaurus had the typical body plan of a sauropod, with an extremely long neck for foraging at the tops of trees and a long tail for balance. However, their necks were also quite thicker than other sauropod groups. It's thought they may have swung them against each other in dominance battles, much like modern giraffes.

This specimen is a fossil bone chunk from the Apatosaurus recovered on private land in the Morrison Formation in Utah. This geologic formation is 150,000,000 years old and one of the best studied deposits of Jurassic material.

These showcase Apatosaurus specimens are shipped in a sturdy cardboard carton along with an informational card and certificate of authenticity. Several other Apatosaurus specimens are available in the collection below.

First described in 1879, Apatosaurus is one of the best-known of all sauropods. In the public mind, this popularity is due to early confusion that led to the skulls of other sauropods being mounted on their skeletons under the name of Brontosaurus. Currently the Apatosaurus and Brontosaurus genera are taken to constitute the Apatosaurinae, a subfamily of diplodocid sauropods. Apatosaurus includes at least two recognized species: Apatosaurus louisae, which may have reached 23m long (75ft) and 20 or more tons, and Apatosaurus ajax, a giant on the order of 36 to 80 tons.

The confusion between Apatosaurus and Brontosaurus stems from an incorrect reconstruction by paleontologist Othniel Charles Marsh in 1883. Marsh had found two sauropod remains, one small (dubbed Apatosaurus) and one large (dubbed Brontosaurus), but neither had a complete skull. Years later, when Marsh attempted a reconstruction of the latter, he incorrectly mounted a stubbier Camarasaurus skull onto the assemblage, further confusing matters. Later research revealed that Marsh's Apatosaurus and Brontosaurus were not distinct genera, but a younger and older specimen of the same group.

Conventions of scientific naming dictate that the original name should be kept while the subsequent is abandoned, but because of Marsh’s Camarasaurus reconstruction, the latter name was better known and it stuck. Brontosaurus was used incorrectly by the public to refer to Apatosaurus, while the actual Brontosaurus genus was believed to be dubious. The genus remains a point of controversy — research in 2015 suggested that Brontosaurus is a valid genus, closely related to Apatosaurus, but this is not entirely accepted by the paleontological community.

Apatosaurus showed the typical diplodocid design of a long neck, a very long and whip-tapered tail, and a small, low-set head with peg-like teeth. But Apatosaurs were more heavily-built sauropods than the related North American diplodocids Diplodocus and Barosaurus, with a substantially thicker neck that may have been adapted for wielding in dominance battles with their own kind, rather like the bull giraffes of today.

Contemporaneous sauropods appear to have coexisted by pursuing different modes of browsing. A 2018 analysis assessing Apatosaurus and Diplodocus specimens from the Morrison Formation in Colorado concluded that the former had higher tooth-replacement rates than the latter, suggesting Apatosaurus may have fed more heavily on tougher plant life than Diplodocus, such as conifers and cycads.