The lower Miocene cytherellids (Crustacea, ostracoda) from the pelotas basin and their significance for the south atlantic paleozoogeography

Abstract

A taxonomic study of the family Cytherellidae Sars was carried out in Lower Miocene deposits of the well 2-RSS-1 (Pelotas Basin, southeastern Brazilian margin). Five species were recognised, two of them describe herein: Inversacytherella atlantica sp. nov. and Cytherella pelotensis sp. nov. Cytherella pleistocenica Bergue et al. is reassigned into Inversacytherella Swanson et al. This is the first report of the genus Inversacytherella in the Atlantic. Three species are left in open nomenclature due to the scarcity of specimens. One of them is tentatively identified as Grammcythella Swanson et al., a genus that has been recorded so far only in the Oceania. The occurrences of Inversacytherella and Grammcythella constitute additional evidence for faunal interchanges between America and Oceania, triggered by hydrological changes in the Southern Ocean during the Neogene.