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The process of interpreting and evaluating a fossil is a difficult task. Isopoda is a species rich group of peracarid eumalacostracans which represent quite a challenge when found as fossils, independent of whether we are working with fragmentary or more complete specimens. Here we describe a new fossil species of crustacean, Platuropodus odysseus n. gen. n. sp., from the Irati Formation, Permian of Paraná Basin, Brazil. After misinterpretations, the fossil taxon is recognised here as a representative of Isopoda. The new species presents characters found in Phreatoicidea, Asellota and Oniscidea in a unique combination for the fossil and extant record, such as two pairs of sub-chelate anterior trunk appendages, a short region after the anus and flat uropods. This chimera-like morphology and a morphometric analysis of the sub-chelae indicate convergent evolution in the early diversification of Isopoda. The morphological diversification present in the Palaeozoic and Mesozoic fossil record of Eumalacostraca indicate a “push of the past” effect in different ingroups of Peracarida., RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA , V. 127 N. 2 (2021)

Made available in DSpace on 2022-04-29T08:30:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-09 The Regência paleocanyon, recognized in the subsurface of the Espírito Santo Basin, was carved from the Cretaceous and filled up until the middle Eocene. Data from 31 seismic sections, 29 wells, and biostratigraphic markers have substantiated the conception of geological models that enhance knowledge about the evolution and morphology of the paleocanyon. The results include stratigraphic correlations, structural geology interpretations, and stratigraphic surfaces determination (tops of the Mariricu, São Mateus, Regência, and Urucutuca formations), morphologic contour maps and schematic sections. Since its beginning, the Regência paleocanyon was related to faults in the basement. A first, long shallow channel is evidenced near the top of the Aptian Mariricu Formation. The paleocanyon is divided into proximal and distal blocks by an N-S system of normal faults designated as Cedro-Rio Doce Fault Zone (ZCCRD). The morphology of the paleocanyon was also controlled by smaller normal faults with SW-NE direction. These faults originated in the basement and were active until the almost complete fill of the paleocanyon. Normal faults were also determinant in the carving of a secondary large channel in the southwestern region, as well as other smaller channels along the northern margin. In the proximal region, late Cretaceous deposits may have been preserved due to its downward movement and rotation along normal faults. It can be inferred that, during the Eocene, both the proximal region and the paleocanyon depocenter were infilled by sediments from the same source. Seismic reflectors evidence the occurrence of abundant, stacked cut-and-fill channels in the lower part of the paleocanyon and upslope gradation to scattered channels. The set of interpretations is schematically synthesized through an evolutionary and depositional geological model. Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Programa de Pós-Graduação em Geociências e Meio Ambiente, Avenida 24A, 1.515 Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Departamento de Geologia Aplicada Fundacao Para O Desenvolvimento da Universidade Estadual Paulista Julio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Laboratório de Integração de Dados Sísmicos e Geológicos Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Programa de Pós-Graduação em Geociências e Meio Ambiente, Avenida 24A, 1.515 Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Departamento de Geologia Aplicada Fundacao Para O Desenvolvimento da Universidade Estadual Paulista Julio de Mesquita Filho - UNESP Instituto de Geociências e Ciências Exatas Laboratório de Integração de Dados Sísmicos e Geológicos

Silica permineralized stem fragments from six municipalities of São Paulo, Brazil, belonging to the Passa Dois Group, Corumbataí Formation (Guadalupian, Permian), were analysed. Morpho-anatomic characteristics of the stems and steles, observed on petrographic slides or polished sections, have permitted the classification of many specimens as Tietea cf. Tietea singularis. A stem piece from the region of Casa Branca, determined as Psaronius cf. Psaronius arrojadoi, corresponds to the first true record of this genus in the Paraná Basin. A generic/specific identification was not possible for radicular mantle samples having no preserved steles. Despite the strong influence of taphonomic factors on the record, all known Marattiales fossils from the Paraná Basin in Brazil present relatively small steles and meristeles, and that may be related to hydric stress. Taphonomic, paleoecological and biogeographical aspects of the analysed fossils are discussed as well., Foram analisados fragmentos de caules permineralizados por sílica de filicíneas arborescentes, procedentes de seis municípios do estado de São Paulo, pertencentes ao Grupo Passa Dois, Formação Corumbataí (Guadalupiano, Permiano). Características morfo-anatômicas principalmente dos estelos, observadas em lâminas petrográficas e/ou superfícies polidas dos caules, contribuíram na classificação de diversos exemplares como Tietea cf. Tietea singularis. Um exemplar de Casa Branca, determinado como Psaronius cf. Psaronius arrojadoi, corresponde ao primeiro registro seguro do gênero para a Bacia do Paraná. Não foi possível a identificação genérica/específica das amostras que apresentam apenas os mantos radiculares preservados. Ainda que os fatores tafonômicos tenham influenciado no registro fossilífero, todos os fósseis conhecidos de Marattiales da Bacia do Paraná na porção brasileira exibem estelos e meristelos relativamente pequenos, o que pode sugerir estresse hídrico. São também discutidos aspectos tafonômicos, paleoecológicos e paleobiogeográficos dos fósseis analisados.