Apatosaurus Vertebra on Stand

Morrison Formation, Wyoming Apatosaurus is a sauropod dinosaur that lived in North America during the Late Jurassic. A cousin to the Diplodocus dinosaur found in the Morian Hall of Paleontology, Apatosaurus was between 69-75 feet long, and weighted 16-22 tons. Apatosaurus held its head and neck parallel to the ground, rather than straight up into the air like a giraffe. To help reduce the weight of its vertebrae, the dinosaur had a series of air sacs that grew out of their lungs and throats, and into their bones.