Apatosaurus considered a junior synonym of "Apatosaurus"; its only species was reclassified as "A.excelsus" in 1903. A 2015 study concluded that "Brontosaurus" is a valid genus of sauropod distinct from "Apatosaurus", but not all paleontologists agree with this division. As it existed in North America during the late Jurassic, "Apatosaurus" would have lived alongside dinosaurs such as "Allosaurus", "Camarasaurus", "Diplodocus", and "Stegosaurus". "Apatosaurus" was a large, long-necked, quadrupedal animal with a long, whip-like tail. Its forelimbs were slightly shorter than its hindlimbs. Most size estimates are based on specimen CM3018, the type specimen of "A.louisae". In 1936 this was measured to
Dinosaur Park dinosaurs at the now closed Dinosaur World in Beaver, Arkansas. The park is located at 940 Skyline Drive and is maintained by the city of Rapid City. Admission is free, however steep flagstone stairs may limit handicapped accessibility. The park was listed on the National Register of Historic Places on June 21, 1990. Dinosaurs represented in the park include "Apatosaurus", "Tyrannosaurus rex", "Triceratops", "Stegosaurus", and an "Edmontosaurus annectens" (formerly "Anatotitan" which itself formerly "Trachodon"). A "Protoceratops" and a "Dimetrodon" ("Dimetrodon" is not actually a dinosaur, but rather a synapsid, and more closely related to mammals than reptiles) were added later