Amargasaurus cazaui. A sauropod dinosaur with enormous vertebral spines that, so far, have been speculated to be either horny sheath covered quills, the supports for a giant camel-like hump, or the supports for an enormous sail that could have been used for thermoregulation or display. The fact that any of the three was probably used in some sort of display tactic is a good possibility though either to ward off predators or attract mates or perhaps both. Amargasaurus is another southern hemisphere dinosaur, discovered in Argentina, and dating to the Early Cretaceous time period. It is a single species genus and a member of the family Dicraesauridae, which includes two other genera and belongs to the superfamily Diplodocoidea, which obviously includes in its ranks Diplodocus and Apatosaurs. All of these animals are considered "whip tailed" meaning that Amargasaurus most likely possessed the same type of thin gracile tail which could be used like a whip in defense and was probably able to carry out some function as a communication facilitator (Myhrvold and Currie, "Supersonic Sauropods? Tail Dynamics in the Diplodocids," 1997).