Felipe Simbras

A Bacia Bauru constitui uma depressao desenvolvida na parte centro-meridional da Plataforma Sul-Americana, formada por subsidencia termo-mecânica no Cretaceo, apos a ruptura do continente gondwânico e abertura do Oceano Atlântico. Na regiao sudoeste do estado de Sao Paulo, porcao central desta bacia, existem quatro propostas estratigraficas. Uma destas mapeia as formacoes Caiua, Santo Anastacio, Adamantina e Presidente Prudente. Aqui sao reportados os resultados da analise estratigrafica das sucessoes sedimentares do intervalo superior do Grupo Bauru na regiao de Alfredo Marcondes, inicialmente mapeada como Formacao Adamantina, Cretaceo Superior. Para identificar o paleoambiente e a unidade estratigrafica foi feita a analise de elementos arquiteturais com perfis litofaciologicos e com paineis estratigraficos dos afloramentos levantados, alem da analise petrografica. As principais macroformas identificadas sao a planicie de inundacao (OF), que alcanca 10 metros de espessura em alguns...

Abstract Over the past few decades, important fossils of dinosaurs, crocodylomorphs, and other latest Cretaceous vertebrates have been recovered from the Bauru Group of Brazil, giving unique insight into how Gondwanan faunas were evolving before the end-Cretaceous asteroid impact. Most of these records, however, come from a few regions, most notably Mato Grosso, western Sao Paulo, and Triângulo Mineiro. Here we describe a fossil reptile assemblage from the Late Cretaceous of the Adamantina and Marilia formations (Bauru Group, Parana Basin) in a region that has gone largely unexplored: southern Goias State. Although these fossils are isolated and largely incomplete, they record a high diversity of vertebrates, including podocnemidoid turtles, crocodyliforms, and titanosaurid dinosaurs. As previous records from this region were limited to a single indeterminate sauropod bone, these new fossils are the first diagnostic members of their groups from southern Goias State. Despite the fragmentary condition of the new fossils, they demonstrate that the local fauna was diverse during the latest Cretaceous, and generally similar to Bauru Group faunas from other parts of Brazil. These fossils lend further support to the hypothesis that a diverse terrestrial fauna, dominated by dinosaurs and crocodylomorphs but also including turtles, was widespread across South America (and possibly Gondwana) during the very end of the Cretaceous Period.

ABSTRACT The South American sauropod dinosaurs fossil record is one of the world’s most relevant for their abundance (51 taxa) and biogeographical implications. Their historical biogeography was influenced by the continental fragmentation of Gondwana. The scenery of biogeographic and stratigraphic distributions can provide new insight into the causes of the evolution of the sauropods in South America. One of the most important events of the sauropods evolution is the progressive replacement of Diplodocimorpha by the Titanosauriformes during the early Late Cretaceous. The fluctuation of the sea levels is frequently related to the diversity of sauropods, but it is necessary to take into account the geological context in each continent. During the Maastrichthian, a global sea level drop has been described; in contrast, in South America there was a significant rise in sea level (named ‘Atlantic transgression’) which is confirmed by sedimentary sequences and the fossil record of marine vertebrates. This process occurred during the Maastrichtian, when the hadrosaurs arrived from North America. The titanosaurs were amazingly diverse during the Late Cretaceous, both in size and morphology, but they declined prior to their final extinction in the Cretaceous/Paleocene boundary (65.5Yrs).

ABSTRACT We report new theropod dinosaur material from the Presidente Prudente Formation (Campanian–Maastrichtian), Bauru Group, in southwestern São Paulo state. The material comprises a fragment of right maxilla of Carcharodontosauridae, an anterior portion of a left ilium of Abelisauroidea and a proximal portion of a right fibula of a coelurosaurian. Previous theropod records from the Bauru Basin comprise Abelisauridae and Tetanurae and in São Paulo state these have been represented by only a right premaxilla of an abelisaurid and isolated abelisaurid and carcharodontosaurid teeth. The new material reported here represents the first theropod remains from the Presidente Prudente Formation, and includes the first abelisauroid and coelurosaurian postcranial remains from the Bauru Basin in São Paulo state and the first latest Cretaceous carcharodontosaurid known from non-dental remains anywhere.

The Crocodyliformes are the most represented vertebrate clade in the Upper Cretaceous sequences of the Bauru Group, Paraná Basin. However, some of the species described have an uncertain taxonomic status and phylogenetic position. For instance, "Goniopholis" paulistanus has been assigned as a nomem dubium, due to its description being based on scarce material. The "G". paulistanus specimens (i.e. teeth and a left tibia) were discovered in two different localities in São Paulo state: Mirandópolis and Valparaíso municipalities; where the upper interval of the Adamantina Formation (Early Maastrichtian of Bauru Group) crops out. Revisiting these specimens, we observed multicrenulated teeth in middle dentary toot- row, a remarkable feature only shared with teleosaurids Machimosaurus hugii (Upper Jurassic of Laurasia) and M. rex (Lower Cretaceous of Tunisia). This apomorphy was also recognized in new material from the Alfredo Marcondes municipality (Presidente Prudente...

The mesoeucrocodylian record from the Bauru Group (Paraná Basin, Brazil) comes from three formations: Adamantina (Late Turonian-Early Maastrichtian), Presidente Prudente (Early Campanian-Early Maastrichtian) and Marília (Maastrichtian). These records are restricted to the Early Coniacian-Early Maastrichtian. Here, we report a new crocodyliform record from the Bauru Group, which was the first of the Araçatuba Formation, from a new locality of Coronel Goulart district, in Álvares Machado municipality. Coronelsuchus civali gen. nov. et sp. nov. comprises two related specimens - FFP PG 13 and FFP PG 14 recovered close to each other and on the same muddy sandstone level. We perform a phylogenetic analysis with 392 characters (five new added) and 88 taxa. Our analyses supported the new clades: Sphagesauria, Sphagesaurinae and Caipirasuchinae. Our phylogenetic results suggest C. civali as a basal Sphagesauria. Regarding the Crocodyliform Assemblage Zones (CAZ), the new species is correlate...