UNRAVELLING THE JURASSIC RADIATION OF AVEROSTRA (DINOSAURIA, THEROPODA) FROM NEW DATA OF ITS MOST COMPLETE ARGENTINIAN EARLY REPRESENTATIVES AND EXHAUSTIVE PHYLOGENETIC ANALYSES

ended

Averostra is the major-group of theropod dinosaurs that includes Tetanurae and Ceratosauria, and it constitutes one of the most debated monophyletic groups within Theropoda, due to the unclear interrelationship of its basal members and the relationships between their major clades. From Early to Late Jurassic, an explosive radiation of Averostra happened, the Pliensbachian-Toarcian extinction event probably being one of the major causes for the explosive evolution of theropods and the radiation of averostrans. The consequent rapid radiation following this extinction event and the increase of morphological changes might be closely related to high peaks of homoplasy in the basal nodes within these principal clades. These homoplastic peaks together with the fragmentary nature of the fossil record of the basal members could be the cause of the problematic phylogenetic relationship of its taxa. Through this research project, I aim to obtain a robust and synthetic view of the evolutionary drivers of the radiation of Averostra during the Jurassic, in order to explore when averostrans originated at the latest, and unravel the impact of the Pliensbachian-Toarcian extinction on their radiation and how the different lineages were established in the aftermath. To achieve this goal, the most complete early members of the two main averostran lineages, Ceratosauria and Tetanurae, the probably late Early Jurassic species from Chubut (Argentina), Eoabelisaurus mefi and Asfaltovenator vialidadi, will be studied in detail. These taxa are exceptionally complete and show unique character combinations, which will be essential for reconstructing character transformations and the role of homoplasy in the early evolution of Averostra. The opportunity to lead my research to the origin of the most important lineage of Theropoda would imply the enhancement of my knowledge in this matter and the development of my paleontological career.