Apatosaurus of gigantic sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including "Diplodocus", "Supersaurus", and "Barosaurus". "Apatosaurus" is sometimes classified in the subfamily Apatosaurinae, which may also include "Suuwassea", "Supersaurus", and "Brontosaurus". Othniel Charles Marsh described "Apatosaurus" as allied to "Atlantosaurus" within the now-defunct group Atlantosauridae. In 1878 Marsh raised his family to the rank of suborder, including "Apatosaurus", "Atlantosaurus", "Morosaurus" (="Camarasaurus") and "Diplodocus". He classified this group within Sauropoda, a group he erected in the same study. In 1903 Elmer S. Riggs said the name Sauropoda would be a junior synonym of earlier
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