New contributions to the taxonomy of non-marine ostracods from the Neogene megawetlands, western Amazonas state, Brazil

Abstract

The taxonomic review of the ostracods from Solimões Formation in the western Amazonas State, Brazil, allowed the identification of eight genera and twenty-two species of the genus Cyprideis Jones, 1857. Two species are new: Cyprideis goeldiensis sp. nov and Cyprideis javariensis sp. nov.; and Cyprideis sp. 1 remains in open nomenclature. For the first time, the species Cyprideis santaelenae Sousa and Ramos 2023, originally described to the Pebas Formation, in Peru, was recorded in the Solimões Formation. A new morphotype of the species Cyprideis matorae Gross et al. 2014 is here identified. The stratigraphical distribution of the Cyprideis species in the borehole 1AS-32-AM permitted the identification of four ostracod zones: Cyprideis caraionae Zone, Cyprideis minipunctata Zone, Cyprideis cyrtoma Zone and Cyprideis paralela Zone, presenting a time range from the middle Miocene (Serravallian) to the late Miocene (Tortonian). Based on the ostracod assemblage, an environment of a semiconfined lake, with mesohaline features and sporadic marine influence is attested to the western Amazonia during the Miocene. The species turnover of Cyprideis occurred during the Tortonian.