MEANING: "Universidad de la República" giant
PERIOD: Late Cretaceous
CONTINENT: South America
Udelartitan is a titanosaurian sauropod from the Late Cretaceous of what is now Uruguay. It had the typical sauropod body plan, standing on four thick pillar-like legs, and possessing a long neck. Titanosaurs are a very diverse group, Udelartitan was a small one, estimated at only 15 m in body length. Though a skull has yet to be discovered, it probably had peglike teeth, and a large gut for processing vegetation.
Abstract from paper: The up to 200 m thick Upper Cretaceous deposits of Uruguay includes from base to top the Guichón, Mercedes, and Asencio formations, plus the lateral correlate of the latter, the Queguay Formation. In 2006, the most complete sauropod from the country was excavated from the Guichón Formation near Araújo, Paysandú Department. Augmented by new specimens reported here, the material includes sixty caudal vertebrae (all strongly procoelous, except for the biconvex first one), a partial coracoid, long bone fragments (proximal and distal portions of tibia, proximal portion of fibula), two astragali, and six metatarsals, as well as associated eggshell fragments. The Uruguayan titanosaur shows a unique combination of characters (biconvex first caudal centrum, pneumatic foramina in the anteriormost caudal centra, dorsal tuberosities on the transverse processes of the anterior caudal vertebrae, well developed fibular knob, pyramidal astragalus), as well as a potential autapomorphy – middle caudal centra condyles with hexagonal contour – allowing the proposition of new genus and species, Udelartitan celeste. Phylogenetic analyses were for the first time performed to assess the relations of that taxon, which was recovered either as a saltasaurine saltasaurid or a non-saltasaurid saltasauroid. Further, one of the analyses show Udelartitan celeste nested within a clade including Late Cretaceous titanosaurs with a biconvex first caudal vertebra, such as Alamosaurus sanjuanensis, Baurutitan britoi, and Pellegrinisaurus powelli. This contribution demonstrates that at least two titanosaur lineages were present in the Late Cretaceous of Uruguay: Saltasauroidea and Aeolosaurini, the latter recently recognized in the stratigraphically younger Asencio Formation.
Udelartitan is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Udelartitan is a sauropod. Sauropods are saurischian dinosaurs that had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Brachiosaurus, Diplodocus, Apatosaurus and Brontosaurus.
The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic, and by the Late Jurassic (150 million years ago), sauropods had become widespread. By the Late Cretaceous, one group of sauropods, the titanosaurs, had replaced all others and had a near-global distribution. This group included the largest animals ever to walk the earth. Estimates vary, but the largest titanosaurs are estimated at upward of around 40 m, and weighing 100 t, or possibly even more.
As with all other non-avian dinosaurs alive at the time, the titanosaurs died out in the Cretaceous–Paleogene extinction event. Fossilized remains of sauropods have been found on every continent, including Antarctica.