Antarctosaurus
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? Antartosaurus Conservation status: Fossil
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| A. giganteus A. wichmannianus(type species) ?A. brasiliensis |
Antarctosaurus (ant-ARK-to-sawr-us) meaning "southern lizard", because it was found at the southernmost tip of South America ( Greek antarktikos = southern + sauros = lizard) was a herbivorous titanosaur which existed in the late Cretaceous, approximately 75 mya. This quadruped would have reached a length of around 18m, a height of 6m, and a weight of 40 to 70 tons, making it one of the largest South American sauropods and among the largest dinosaurs ever - it is related to the similarly gigantic Argentinosaurus.
The first fossils were found in 1916, and others have since been found in India, Argentina, Uruguay, Chile, Brazil, Kazachstan and Africa [1], and it is possible that it really did live in Antarctica. Parts recovered include two femora, two incomplete pelvises and numerous other fragments. One of the femora was 2.20m in length, and it is mainly from this that the astonishing size of the dinosaur is extrapolated. The postcrania, however, suggest that its head was barely 60cm long [2].
The taxonomic classification of Antarctosaurus is, like that of many dinosaurs, highly disputed. The type specimen may actually be a small Antarctosaurus, as another specimen has recently been recovered that is double the size of the type specimen. Originally this dinosaur was placed in a separate species, but they are now both thought to be A. wichmannianus. There are other problems with the type specimen, including that its lower jaw is now thought to belong to a rebbachisaurid [3]. Whether Antarctosaurus is even a titanosaur at all is now uncertain; it was placed into Diplodocidae in 1993, but returned to Titanosauridae in 1997 [4]. Also, Jainosaurus was originally thought to be a species of Antarctosaurus, A. septentrionalis, but it is now recognised as a distinct genus.