Antarctosaurus (/ænˌtɑːrktoʊˈsɔːrəs/; 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, is controversial because there is uncertainty as to whether all the described remains belong to the same individual or even genus.

Remains of this dinosaur were first mentioned in print in 1916,[1] although they were not fully described and named until a 1929 monograph written by paleontologist Friedrich von Huene.

The generic name refers to the animal's reptilian nature and its geographical location on a southern continent.

Antarctosaurus wichmannianus is the type species of the genus, named in 1929 after the discoverer of its remains in 1912, geologist Ricardo Wichmann.

[2] Von Huene used the name A. wichmannianus to describe a large assemblage of bones, which are considered to come from the Anacleto Formation in Río Negro Province of Argentina,[3] which is probably early Campanian in age.

[5] Von Huene also named a fragmentary second species of Antarctosaurus in the same 1929 monograph, which he tentatively called cf.

[3] These fossils were recovered in Neuquén Province of Argentina, from the Plottier Formation,[3][6] which dates to the Coniacian-Santonian stages of the Late Cretaceous Period.

[8] In 1969, Leigh Van Valen considered A. wichmannianus and A. giganteus to be growth stages of the same species and favored the name A.

[10] In 1933, Von Huene and Charles Matley described another species, Antarctosaurus septentrionalis, meaning "northern".

It may have come from the Syuksyuk Formation (originally described as Dabrazinskaya Svita) which dates to the Santonian stage of the Late Cretaceous.

[13] The remains that have been described belong to sauropods, most probably titanosaurs,[3] a group of large-bodied, quadrupedal herbivores, usually possessing a long neck and tail, with a small head.

In particular, the very square lower jaw has frequently been suggested to belong to a rebbachisaurid sauropod similar to Nigersaurus.

[26][31] The back of the skull and the remainder of the skeleton are usually regarded as titanosaurian by researchers, although they do not necessarily belong to the same type of titanosaur.

[7][27][32] In 2005, Jeffrey Wilson considered the braincase as being referable to Nemegtosauridae but noted that other skull remains require further study.

[17] A study, published in 2012 by Ariana Paulina Carabajal, CT scanned the A. wichmannianus braincase which revealed the complete brain endocast and the inner ear structures.

He noted, however, that the comparison was potentially misleading because the overall anatomy of Saltasaurus is shorter and stouter which might facilitate a bigger skull.

[25] In 2006, Kenneth Carpenter used the relatively short-necked Saltasaurus as a guide and estimated a length of 23 meters (75 ft) long.

[14][16] Paleontologist Teresa Maryańska noted that, whilst A. jaxarticus was named, it was not properly described or diagnosed.

[42] Andesaurus Ruyangosaurus Daxiatitan Xianshanosaurus Malawisaurus Epachthosaurus Muyelensaurus Rinconsaurus Pitekunsaurus Antarctosaurus Jainosaurus Vahiny Normanniasaurus Argentinosaurus Futalognkosaurus Mendozasaurus Notocolossus Patagotitan Puertasaurus Nemegtosaurus Tapuiasaurus Aeolosaurus Rapetosaurus Alamosaurus Isisaurus Saltasaurus Opisthocoelicaudia Diamantinasaurus Savannasaurus