The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction

ABSTRACT The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work

CroSSED sequence, a new tool for 3D processing in geosciences using the free software 3DSlicer

The research by JD was funded through a European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No 792314 (ICON-SE). The research of FJR-T was funded by projects CGL2015-66835-P and PID2019-104625RB-100 (Secretaria de Estado de Investigacion, Desarrollo e Innovacion, Spain), B-RNM-072-UGR18 (FEDER Andalucia), P18-RT-4074 (Junta de Andalucia), and Scientific Excellence Unit UCE-2016-05 (Universidad de Granada). The research was conducted within the "The Drifters Research Group" (RHUL) and the "Ichnology and Palaeoenvironment Research Group" (UGR). We thank Russell Garwood and one Anonymous Reviewer for their valuable comments on the manuscript and David Nesbitt and Jean Sanders for editing the English.The scientific application of 3D imaging has evolved significantly over recent years. These techniques make it possible to study internal features by non-destructive analysis. Despite its potential, the development of 3D imaging in the Geosciences is behind other fields due to the high cost of commercial software and the scarce free alternatives. Most free software was designed for the Health Sciences, and the pre-settled workflows are not suited to geoscientific materials. Thus, an outstanding challenge in the Geosciences is to define workflows using free alternatives for Computed Tomography (CT) data processing, promoting data sharing, reproducibility, and the development of specific extensions. We present CroSSED, a processing sequence for 3D reconstructions of CT data, using 3DSlicer, a popular application in medical imaging. Its usefulness is exemplified in the study of burrows that have low-density contrast with respect to the host sediment. For geoscientists who have access to CT data and wish to reconstruct 3D structures, this method offers a wide range of possibilities and contributes to open-science and applied CT studies.European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant 792314Secretaria de Estado de Investigacion, Desarrollo e Innovacion, Spain CGL2015-66835-P PID2019-104625RB-100FEDER Andalucia B-RNM-072-UGR18Junta de Andalucia P18-RT-4074Universidad de Granada UCE-2016-0