Sauropoda

Sauropoda is a clade of saurischian, or lizard-hipped, dinosaurs, whose members are known as sauropods. They are the largest animals ever to have lived on land, with very long necks, long tails, small heads relative to the body, and four thick, pillar-like legs supporting massive bodies. Air-filled, hollow bones are a characteristic feature of the group, lightening the enormous skeleton and aiding a bird-like system of air sacs. Well-known members include Diplodocus, Apatosaurus, Brachiosaurus, Camarasaurus, and the giant titanosaurs such as Argentinosaurus. The oldest unequivocal sauropods appear in the Early Jurassic; by the Late Jurassic groups like the diplodocids and brachiosaurids had become widespread, and by the Late Cretaceous the titanosaurs had replaced all other sauropods and achieved a near-global distribution. Their fossils have been found on every continent, including Antarctica.