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A systematic study is made of Early Cretaceous (late Aptian/earlyAlbian) ostracod assemblages from the Santo Antônio section. This section is characterized by sediment belonging to the post-rift sedimentary sequence of the Romualdo Formation in the southern-central region of the Araripe Basin, Brazil and represents on of the first marine ingression in the interior of the continent, during the beginning of the formation of the Atlantic Ocean. The Santo Antonio section presents ostracods in greater diversity than previously known. Nineteen samples were analyzed, yielding a total of 8,370 specimens. Fifteen taxa were identified, including six brackish ostracods: Pattersoncypris salitrensis, Pattersoncypris angulata, Pattersoncypris micropapillosa, Damonella grandiensis, Alicenula cf. leguminella and Theriosynoecum cf. quadrinodosum; and nine typically brackish-marine species, including seven new ones: Dicrorygma cf. minuta, Dicrorygma (Orthorygma?) dimorpha, Mongolianella aptianensis sp. nov., Mantelliana speculum sp. nov., Paracypris undulareventralis sp. nov., Microceratina retangularis sp. nov., Perissocytheridea oculusutilis sp. nov., Perissocytheridea poruslinearis sp. nov. and Perissocytheridea florisdorsalis sp. nov. Therefore, the detailed taxonomic study brings a new understanding of marine ostracods around the upper Aptian/lower Albian boundary of the Araripe Basin.

Novas espécies de ostracodes são propostas para rochas do Permiano Médio a Superior (Guadalupiano) da Formação Teresina, Bacia do Paraná, em duas localidades no Estado de São Paulo, sudeste do Brasil: Represa Xavante e Pedreira Pau Preto. Paranacythere nigripallus gen. nov. e sp. nov., Velatomorpha xavante sp. nov., and Velatomorpha pseudoaltilis sp. nov. são descritas. A associação entre os gêneros Velatomorpha e Paranacythere é interpretada como típica de ambientes mixoalinos da Formação Teresina, e são os ostracodes mais abundantes nas localidades aqui estudadas. Paranacythere nigripallus gen. nov. e sp. nov. é proposto para acomodar uma espécie com características tipicamente cytheroides e tentativamente atribuído à família Cytheruridae. Aspectos ecológicos são discutidos com base na estrutura populacional etária, biostratinomia e composição taxonômica das assembleias. É proposta uma emenda à diagnose de Velatomorpha Tibert & Dewey. New ostracod species are described for Middle to Upper Permian (Guadalupian) rocks of the Teresina Formation, Paraná Basin, from two localities in the São Paulo State, southwestern Brazil: Xavante Dam and Pau Preto Quarry. Paranacythere nigripallus gen. nov. and sp. nov., Velatomorpha xavante sp. nov., and Velatomorpha pseudoaltilis sp. nov. are herein described. The association Velatomorpha– Paranacythere is proposed as typical of Permian mixohaline environments of the Teresina Formation, and is the most abundant in the two studied localities. Paranacythere nigripallus gen. nov. and sp. nov. is proposed to accommodate a very abundant species with typically cytheroidean characteristics, and tentatively ascribed to the family Cytheruridae. Some ecological remarks are presented based on ostracod population age structure, biostratinomy and taxonomic composition of assemblages. The diagnosis of Velatomorpha Tibert & Dewey is emended.

Microfossils have been found in most of the Mesozoic basins of Brazil, allowing the establishment of important biozones. Despite being recognized for more than half century in the Barremian from the Reconcavo Basin, the taxonomy of the benthic foraminifera remained unsolved likewise its paleoenviromental implications. In this study, we have applied 2D and 3D imaging techniques to resolve this issue and have identified two agglutinated foraminiferal genera (Glomospirella and Paratrochamminoides) and a new species Paratrochamminoides kaminskii sp. nov. Moreover, based on the taxonomy, few paleoenvironmental insights on the foraminifera-bearing strata are discussed. The occurrence of the typically shallow marine species Glomospirella arctica in the studied section, does not allow the proposition of a marine ingression, since it is not supported by a marine/ transitional association of microfossils. On the other hand, the hypothesis of transport of foraminifera by birds (avian zoocoria) is plausible, although there are no further elements to corroborate it.

Twenty-five species of Podocopida are reported in seven localities in the Sao Paulo State, Brazil, corresponding to the Serra Alta and Teresina formations (Middle to Upper Permian). The specimens are mostly preserved as steinkerns (internal molds), except some carbonitids and cytherocopines which are predominantly recrystallized. The results indicate marginal marine environments influenced by influxes of nonmarine waters, as suggested by the occurrence of Velatomorpha, Gutschickia, Carbonita and Darwinuloidea. Velatomorpha rochacamposi sp. nov. is described, and evidences of predation are reported for the first time in Paleozoic ostracods. This study contributes to the understanding of the ecology and evolution of nonmarine ostracods during the Late Paleozoic.

At the end of the Paleozoic, several intracratonic basins developed in Gondwana, including the Parana Basin in Western Gondwana. Permian sedimentary units include the Passa Dois Group, which encompasses four formations: the Irati, Serra Alta, Teresina, and Rio do Rasto, and represents a transition from marine to continental depositional environments. Its strata correlate extensively, from Argentina to South Africa, and the Irati and Teresina formations in particular present mixed carbonate-siliciclastic successions. This interval has been speculated to have formed under several different paleoenvironmental scenarios; however, Permian Gondwana basin microfacies, with no open sea influence, have rarely been studied. In addition, in these basins there is a scarcity of micropaleontological studies and geochronological calibration, besides an absence of marine index fossils. In view of this, a comprehensive microfacies study for the unit is developed, with a large and representative surface and subsurface sample analysis of the Passa Dois Group, divided into three large geographic domains: north, central, and south of the Parana Basin, Brazil. Thin sections distributed among the four units were analyzed with an emphasis on carbonate layers where the microfossils have a better chance to be recognized. The data were interpreted within a revised biochronostratigraphic framework and integrated with bivalves, macroflora, palynology, conchostracans, and vertebrates biozones. Microfacies analysis resulted in the recognition of 13 microfacies: four siliciclastic, eight carbonate, and one siliceous (chert). We observed a predominance of fine siliciclastic microfacies, rich in organic matter, in the Southern Domain; rudaceous carbonate microfacies in the Central Domain, with diverse allochemicals and the greater diversity of bioclasts; and an increase on siliciclastic sediments influx in the Northern Domain of the basin, where only the Irati and Teresina formations occur. A shortage of microfossils was observed in the South Domain, where the carbonate microfacies are less varied than those to the north. In the Central Domain, coarse-grained carbonates are present. Bivalves, ostracods, and sponge spicules are the main bioclasts on rudstones and grainstones from the Irati and Teresina formations, and have been interpreted as allochthonous to parautochthonous. The association of detrital and authigenic glauconite to bioaccumulations of sponge spicules is interpreted as episodes of marine transgression.