| Austroposeidon | |
|---|---|
 | |
| Twelfth neck vertebra | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Macronaria |
| Clade: | †Titanosauria |
| Clade: | †Lithostrotia |
| Genus: | †Austroposeidon Bandeiraet al., 2016 |
| Species: | †A. magnificus |
| Binomial name | |
| †Austroposeidon magnificus Bandeiraet al., 2016 | |
Austroposeidon is agenus oftitanosauriansauropoddinosaur from theLate CretaceousPresidente Prudente Formation ofBrazil. It contains one species,Austroposeidon magnificus (meaning "Magnificent Southern Poseidon").[1]
Austroposeidon is known from a single specimen,MCT 1628-R, which consists of portions of the cervical (neck), dorsal (back), and sacral (hip) vertebrae (including a cervical rib and one complete dorsal vertebra). The specimen was discovered in theCampanian-MaastrichtianPresidente Prudente Formation of theBauru Group by palaeontologistLlewellyn Ivor Price in an outcrop along the Raposo Tavares Road in 1953, but the remains were not described until 2016. The animal was likely preserved by acrevasse splay on afloodplain, judging by the fine sandstone that the specimen was found in. Unfortunately, the site where the specimen was recovered has now been lost to urban development after Felipe Medeiros Simbras was unable to locate the site.[1]
The genus name combinesaustro ("southern", as in South America, fromLatinAuster, the southern wind) andposeidon, a reference tothe Greek god of earthquakes of the same name. Thespecific name is the Latin wordmagnificus ("great, elevated, noble"), referring to the large size of the specimen.[1]
Austroposeidon was a largesauropod, the largest dinosaur discovered in Brazil, with the only known specimen, an adult, having a length of about 25 metres (82 ft).[1] It is therefore one the largest dinosaurs from Brazil, alongsideUberabatitan.[2]
Several traits show thatAustroposeidon was atitanosaur; thehyposphene-hypantrum articulations are missing from the vertebrae, the cervical and dorsal vertebrae do not have forkedneural spines, and the internal texture of the bone is camellate (punctuated by many small air chambers). The describers determined thatAustroposeidon was a new genus based on a number ofautapomorphies (traits unique to the known fossils) in the vertebrae: the thirteenth cervical vertebra has columnar centropostzygapophyseallaminae, and its rear centrodiapophyseal lamina splits into two prongs; the first dorsal vertebra has front and back centrodiapophyseal laminae that curve downwards and outwards, and its diapophysis stretches down to the top margin of thecentrum; and the frontmost part of the spinoprezygapophyseal laminae forks in the dorsal vertebrae positioned towards the back of the torso. Additionally,Austroposeidon possesses a unique combination of other vertebral traits, not seen elsewhere among titanosaurs.[1]
ACT scan showed that the internal bone texture of the vertebrae possessed concentric, alternating rings of camellate tissue and dense tissue; the describers interpreted these as rings of growth within the bone.[1]
A phylogenetic analysis in 2016 recoveredAustroposeidon as the sister taxon of theLognkosauria.[1] An updated version was published by Silvaet al. (2019), where the only significant changes from the original, based on a redescription ofUberabatitan, was the movement ofUberabatitan andBrasilotitan fromSaltasaurinae toAeolosaurini.[2]
In 2022,Austroposeidon was recovered as a member of Lognkosauria by Navarroet al.:[3]
| Lognkosauria |
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