Abdarainurus

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

Overview: Abdarainurus was a medium-sized sauropod dinosaur that roamed prehistoric Mongolia around eighty million years ago. Fossils of the animal originate from the Alagteeg Formation, so it would’ve inhabited a semi-arid region, which would later become a more desert-like environment, readily observable in the Djadochta Formation that overlies the Alagteeg. Pronounced wet and dry seasons would’ve meant that food availability probably varied throughout the year. Abdarainurus likely subsisted on conifers and other plants. Fossils now referred to Abdarainurus were originally discovered by Russian and Mongolian fossil hunters in the 1970’s, but they would sit packed away in storage, largely ignored until the 2000’s. After preparation, the bones were studied and found to be those of a new genus. Abdarainurus takes its name from the Abdrant Nuru fossil site.

Currently, the only known fossil specimens of Abdarainurus consist of some tail vertebrae, belonging to the upper portion of the tail behind the pelvis. The morphology of these vertebrae was quite odd in comparison to those of most other sauropods, seemingly being adapted for bearing different types of force. Why it evolved such a tail is unclear, though the tail may’ve played some special balancing or defensive role (some sauropods are speculated to have used their tails for defense). There were a few other notable, though more minute details that set Abdarainurus apart. Phylogenetic studies usually classify Abdarainurus as a basal titanosaur. It may’ve represented a unique Asian lineage of titanosaurs, being a possible close relative of the genus Gandititan. Abdarainurus most likely shared its environment with a variety of dromaeosaurid, ankylosaur, ceratopsian, and ornithopod dinosaurs.