Abstract
A new early dinosaur, Unaysaurus tolentinoi gen. et sp. nov., from the continental Late Triassic red beds of the Caturrita Formation (Carnian-Norian, c. 225 million years old) of southern Brazil is described. U. tolentinoi is represented by a semi-articulated skeleton comprising an almost complete skull, lower jaw and postcranial elements. It differs from all other dinosaurs by several cranial (e.g. developed laterodorsally oriented process formed by frontal and parietal; deep ventral depression on the basisphenoid) and postcranial (presence of a conspicuous blunt ridge running on the lateral surface of the deltopectoral crest of humerus) characters. Unaysaurus represents the first prosauropod grade dinosaur from Brazil and a preliminary phylogenetic analysis indicates it to be closely related to the European Plateosaurus (Plateosauridae). The relationships of the Prosauropoda , however, are still controversial and more comprehensive studies are needed before a clear picture of the evolution and paleobiogeographic distributions of these dinosaurs can be presented.References
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