The titanosaurs, however, were some of the largest sauropods ever. Potential prey included ornithopods, stegosaurids, and sauropods. The sauropods were the largest and heaviest dinosaurs. It shares some attributes with giant quadrupedal sauropods like "Apatosaurus". It has arm features that are intermediate between prosauropods and sauropods. They are a highly diverse group form the dominant clade of Cretaceous sauropods. Similar aquatic behavior was commonly depicted for other large sauropods, such as "Brachiosaurus" and "Apatosaurus". This shows that dermal armour had a wide distribution in these Late Cretaceous sauropods. "Brachiosaurus" was one of the less abundant Morrison Formation sauropods. They assumed sauropods had a reptilian respiratory system. The proximal caudal vertebrae are extremely diagnostic for sauropods. Various uses have been proposed for the single claw on the forelimb of sauropods. Various uses for the single claw on the forelimb of sauropods have been proposed. The jaws also contained several fenestrae, including three that are not present in other sauropods. Internal organs of these giant sauropods were probably enormous.