Paleobiologia da fauna marinha de bivalves permianos de Cambaí Grande - RS ; Paleobiology of the marine fauna of Permian bivalves from Cambaí Grande - RS

Paleontology is the branch of science that integrates biology and geology and comprises the investigation of fossil organisms serving as study tools that allow the understanding of the evolution of life on Earth. As invertebrate fossils, there are representatives of the Bivalvia or Pelecypoda class of the Paleozoic Cambrian, remaining to these days. During the Upper Paleozoic, this group inhabited the epicontinental seas of the supercontinent Gondwana. At this time, the Paraná Sedimentary Basin was a large epicontinental sea that recorded the occurrence of preserved bivalve mollusks in the deposits of the Rio Bonito Formation. Fossils of this study belong to this geological unit and come from the Cambaí Grande locality, in São Gabriel county – RS. This work aimed the paleobiological study of this fauna through taphonomic, paleoecological and taxonomic analyzes. For the development of the study 55 fossil samples that belong to the scientific collections of UFRGS - Porto Alegre/RS, UNISINOS - São Leopoldo/RS and UNESP-Botucatu/SP were used, and are under loan at the UTFPR-DV Laboratory of Geology, Paleontology and Pedology. The importance of this study is the occurrence of a relevant marine fauna in the context of the Eopermian postglaciation of the Paraná Basin, which was also recorded in coeval geological units of Gondwana. To develop the study 55 fossil samples were used, which were analyzed under the taphonomic, paleoecological and taxonomic aspects. Through research using internal and external shell molds, it was possible to find 7 different morphotypes in the fauna, namely: Heteropecten catharinae, Septimyalina sp., Stutchburia sp., Schizodus sp. and three of them unidentified. It was observed that the amount of left, right and unidentified valves varied among morphotypes; presence of high fragmentation; and predominance of disjoined valves in relation to articulated valves, representing a late burial in relation to the death of bioclasts. The predominant orientation of the shells is concordant in relation ...