Dinosaur diversity and associated faunas in the Cretaceous of South America

Abstract

The Cretaceous Period (ca. 145-66 Ma) encompasses almost the entire second half of dinosaur's evolutionary history, congregating about 70% of its fossil record. Dinosaur diversity at the time was already highly segregated, both geographically and phylogenetically. Hence, groups like hadrosaurs, ankylosaurs, tyrannosaurids, and marginocephalians abound in continents derived from the fragmentation of Laurasia, whereas abelisaurids, spinosaurids, and titanosaurs were more common in gondwanic areas. In South America, Cretaceous dinosaurs are well known from Argentina and some parts of Brazil, as the Bauru and Araripe basins. They are, however, much rarer in other countries and Brazilian basins, what represents an important gap in the knowledge about the group, especially as it comes to the Northwestern third of the continent. Accordingly, this project aims to: 1 - develop a fieldwork program to prospect South-American deposits of Cretaceous age in search for fossil remains of dinosaurs and the associated biota; 2 - conduct revision studies on the anatomy, palaeobiology, and systematics of the recovered key-taxa; 3 - integrate their bearing strata into a comprehensive palaeoenvironmental and chronostratigraphical (based on U-Pb radioisotopic ages from detrital zircon) framework. Fieldwork will explore deposits of three Brazilian basins, i.e., Bauru (in São Paulo and Paraná), Sanfranciscana (in Minas Gerais), and Recôncavo (in Bahia), as well as of three other South American countries, i.e., Bolivia (Cajones Formation), Peru (Fundo el Triunfo Formation), and Uruguay (Paysandú Group). The final aim is to assemble phylogenetic, palaeobiological, geochronological, and palaeoenvironmental data together, in order to advance in the understanding of dinosaur evolution in the Cretaceous of South America. (AU)