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
Barosaurus Barosaurus Barosaurus ( ) was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar "Diplodocus". Remains have been found in the Morrison Formation from the Upper Jurassic Period of Utah and South Dakota (and possibly Africa, as exemplified by the Kadsi Formation). It is present in stratigraphic zones 2-5. The composite term "Barosaurus" comes from the Greek words "barys" (βαρυς) meaning "heavy" and "sauros" (σαυρος) meaning "lizard"; thus "heavy lizard". "Barosaurus" was an enormous animal, with some adults measuring more than 26 meters (85 feet) in length and weighing more than 20 metric tons (22 short tons).