What is Apatosaurus?
{{italictitle}} {{Taxobox | name = ''Apatosaurus'' | fossil_range = [[Upper Jurassic]] 152–150 mya | image = Louisae.jpg | image_width=250px | image_caption = ''A. louisae'' skeleton, [[Carnegie Museum]] | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Sauropsid]]a | superordo = [[Dinosaur]]ia | ordo = [[Saurischia]] | subordo = [[Sauropodomorpha]] | infraordo = [[Sauropoda]] | familia = [[Diplodocidae]] | genus = '''''Apatosaurus''''' | genus_authority = [[Othniel Charles Marsh|Marsh]], 1877}} '''''Apatosaurus''''' is a [[sauropod]] [[dinosaur]] which lived in the [[Upper Jurassic]] period. It is in the same family as ''[[Diplodocus]]''. ''[[Brontosaurus]]'' was once thought a later name for ''Apatosaurus'', but is now proved to be a separate [[genus]]. ''Apatosaurus'' grew as big as 21 meters long, 4.5 meters tall at the hip, and weighed up to 23 metric tons. It ate plants. Its bones have been found in [[Wyoming]], [[Colorado]], [[Oklahoma]], and [[Utah]]. When it was first found, scientists thought that ''Apatosaurus'' lived partly under water, as if it could not hold its own weight on dry land. Now they think it lived on dry land, probably in [[herd]]s. The cervical [[vertebrae]] were less elongated and more solid than those of ''[[Diplodocus]]''. The bones of the leg were much stockier (despite being longer), implying a more robust animal. The tail was held above the ground during normal locomotion. Like most sauropods, ''Apatosaurus'' had only a single large claw on each forelimb, with the first three toes on the hind limb possessing claws. There are at least two [[species]] of ''Apatosaurus'': * ''A. ajax'' was discovered by [[Othniel Charles Marsh]] in 1877. * ''A. louisae'' was discovered by William Holland in 1915. * Another dinosaur species discovered in 1994 was at first named ''A. yahnahpin'', but in 1998, it was renamed [[Eobrontosaurus|''Eobrontosaurus yahnahpin'']]. == Lifestyle == [[File:Apatosaurus caudal vertebrae.png|thumb|Tail vertebrae of specimen FMNH P25112, sh