Titanosaurs were a hugely successful and diverse group of sauropod dinosaurs – giant long-necked herbivores – and are known from Cretaceous rocks all around the world. They are particularly abundant in the Late Cretaceous of South America, and include giants like 30-meter-long Argentinosaurus and 26-meter-long Dreadnoughtus, both from Argentina. Brazil was also home to a giant titanosaur, Austroposeidon magnificus, first discovered in 1953 but only named by Kamila Bandeira and colleagues in late 2016.
Austroposeidon was discovered in rocks of the Presedente Prudente Formation near the town of Presedente Prudente, São Paulo State, southern Brazil. The Presedente Prudente Formation is part of the extensive Bauru Group, deposited in the Late Cretaceous, approximately 90 million years ago. It shared its environment with numerous other dinosaurs, including two much smaller titanosaurs, Gondwanatitan and Brasilotitan, both only around seven meters (23 ft) in length.
The name Austroposeidon is derived from the Latin word austrum meaning southern and Poseidon, the Greek god of the sea who was also responsible for earthquakes. The species name is derived from the Latin term magnificus meaning great or elevated and is a reference to the size of the specimen.