NEW INSIGHTS ON EARLIEST DEVONIAN (LOCHKOVIAN) OSTRACODS FROM THE ARGENTINE PRECORDILLERA?

SALAS, MARIA JOSE

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2016

0002-7014

Abstract. Ostracods from the Early Devonian (Lochkovian) of the Argentine Precordillera Basin (upper levels of Los Espejos and lowermost ones of the Talacasto formations) were studied. These units represent one of the best Lochkovian stratigraphic records in the Malvinokaffric basins. According to this revision the record of the Devonian ostracod fauna of southwestern Gondwana can be extended to older stratigraphic levels. One new genus Suinella and ten species, including five new (Suinella huarpesi gen. and sp. nov., Amphizona? argentinensis sp. nov., Bollia talacastensis sp. nov., Petrisigmoopsis? rotundum sp. nov. and Pircawayra antiqua sp. nov.) and one reassignment (Thilpsurella aff. T. putea Coryell and Cuskley, 1934) are defined. The taxonomic assemblage described differs from younger Devonian Malvinokaffric ostracod associations. Relatively diverse and composed mainly by drepanelloideans together with metacopids, the association is characterized by species with thin and spiny carapaces. This suggests a relatively deep environment, below storm wave base and of low energy. The mix of paleobiogeographic affinities of the Lochkovian ostracod fauna contrast with the clear Malvinokaffric signature of the upper Lower-Middle Devonian associations previously recognized in Argentina.