Antarctosaurus ( //; meaning "southern lizard") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, A. wichmannianus, was described by prolific German paleontologist Friedrich von Huene in 1929, who also described a second species in 1929. Three additional species of Antarctosaurus have been named since then. Later studies indicate that none of these pertain to Antarctosaurus.
Antarctosaurus was very large, even for a dinosaur. Scientists still have much to learn about Antarctosaurus, as a complete skeleton remains elusive.
Antarctosaurus was a huge quadrupedal herbivore with a long neck and tail. It was possibly armoured. As Antarctosaurus is not known from a complete skeleton and tail lengths are highly variable among sauropods, the true size of these animals is hard to extrapolate. The type species may have been over 60 feet (18 meters) long, and a second species may have been one of the largest land animals ever. Antarctosaurus may have been as tall as 15 feet at the shoulder.
Von Huene named a second species of Antarctosaurus in 1929, which he called A. giganteus because of its enormous size. Very few remains are known of this species and it is regarded as a nomen dubium by some. The most famous of these bones are two gigantic femora, which are among the largest of any known sauropod. They measure about 7.75 feet (2.35 meters) in length. Extrapolating from the size of these bones has led to a mass estimate of approximately 69 metric tonnes (152,000 pounds) in one study, just a little smaller than the gigantic Argentinosaurus, which at nearly 73 metric tonnes (160,000 pounds) would have been the heaviest known land animal of all time.
The bones mentioned above were recovered in Neuquén Province of Argentina, from the Plottier Formation, which dates to the late Coniacian stage of the Late Cretaceous Period, or about 87 to 85 million years ago. The Plottier, like the younger Anacleto, is a member of the Neuquén Group.
As so little is known of this animal, and because the material assigned to A. wichmannianus is so confused, A. giganteus cannot be confidently assigned to the genus Antarctosaurus at this time.
Credit to Wikipedia for the article.