Austroposeidon

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Massopoda > Sauropodiformes > Sauropoda > Gravisauria > Eusauropoda > Neosauropoda > Macronaria > Titanosauriformes > Somphospondyli > Titanosauria > Lithostrotia

Overview: Growing to be up to twenty-five meters long and weighing a few dozen tons, this genus is a contender for the largest known Brazilian dinosaur. Fossils of the animal originate from rocks belonging to the Presidente Prudente Formation, layers of which are today exposed in the south of Brazil. The first of these bones were found in the 1950’s, though Austroposeidon wouldn’t be fully described and properly named until 2016. Its generic name means “southern Poseidon” or “Poseidon of the south”, referring to it originating in the southern hemisphere, but also to the Greek sea deity Poseidon. Poseidon was thought to be the origin of earthquakes, so the name is often invoked for large sauropod genera. North America’s Sauroposeidon is one such example.

Austroposeidon was a member of the famous titanosaurian lineage of sauropods, making it related to dinosaurs like Paralititan and Argentinosaurus. It belonged to the clade Lithostrotia, so it was somewhat derived as far as titanosaurs go. Some believe it may’ve belonged to the Lognkosauria, which made Argentinosaurus a potential close relative, but this is debated. As large as this dinosaur was, some lognkosaurs, such as Argentinosaurus itself, grew to even greater proportions. Fully grown Austroposeidon were probably safe from most predators, though the young, weak and elderly would’ve been vulnerable to attacks from large theropods. Most of the traits that set this dinosaur apart from other titanosaurs could be seen on its vertebrae.