Trinisaura

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Ornithopoda > Iguanodontia > Elasmaria

Overview: Trinisaura was an ornithopod dinosaur traditionally classified in the clade Elasmaria – an iguanodontian lineage found only within the southern hemisphere. Fossils of elasmarians originate mainly from South America, Australia, and Antarctica. Trinisaura is from the latter landmass, which in its time was located somewhat farther north, though still within the southern polar region. Most of the world was significantly warmer in the Late Cretaceous, including Antarctica, meaning various plants and animals thrived there, non-avian dinosaurs included. Long periods of cold and darkness still occurred, however. Trinisaura may’ve sported a coat of fur-like integument over most of its body, which we know were present on at least some ornithischian dinosaurs. The region appears to have been covered by temperate rainforests, with both poles being more or less ice free.

Known fossils of this dinosaur include the pelvis, some vertebrae, leg bones, and parts of the arms and shoulder. Based on these fossils, it seems that Trinisaura was similar in appearance to most of its elasmarian relatives. It was a relatively lightly built, bipedal animal. As of yet, no skull material is known, but it most likely possessed a keratinous beak and grinding cheek teeth. Most of its diet is assumed to have consisted of low-level vegetation. Trinisaura fossils are known from Antarctica’s Snow Hill Island Formation, which also contains the remains of another elasmarian – Morrosaurus. The two had a few differences, size included, with Trinisaura being smaller. Trinisaura was formally described in 2013, based on fossils found five years prior on James Ross Island. The generic name of the genus honors Argentine geologist Trinidad “Trini” Diaz, known for her work in Antarctica.