Marine Holocene microgastropods of northeast Buenos Aires Province, Argentina

Marine micromolluscs, especially gastropods, are found in Quaternary marine deposits on the coast of the province of Buenos Aires. In this study, the microgastropods from Holocene beach ridges of northeast Buenos Aires Province are described. Eight localities were analyzed in the SE margin of the Río de la Plata between Berisso and Cerro de la Gloria, Samborombón Bay, in which 5391 individuals of 11 species were recovered. Registration of two species of the subfamily Triphorinae Gray, 1847 not found before for the Quaternary of Argentina, is reported. The species Parvanachis isabellei (d'Orbigny, 1839), Iselica anomala (Lea, 1843), Turbonilla paralaminata Castellanos, 1982 and Turbonilla farinatiae (Pimenta and Absalão, 2004) were first recorded in Quaternary marine deposits of the study area, hence extending their geographical distribution during the Holocene. Most of the species here listed are currently living in the Atlantic Coast of the Buenos Aires Province, except for T. farinatiae, I. anomala and the Subfamily Triphorinae, which do not reach the Argentine coast. The presence of T. farinatiae, I. anomala, and the Subfamily Triphorinae, together with warm water species such as Calliostoma carcellesi (Clench and Aguayo, 1940), Heleobia australis (d'Orbigny, 1835) and Epitonium georgettinum (Kiener, 1838) in the Holocene deposits suggest warm paleotemperatures during the MIS 1 Interglacial in this region.