Lower and Middle Devonian Malvinokaffric ostracods from the Precordillera Basin of San Juan, Argentina

Ostracod from the upper Lower to Middle Devonian rocks of the Argentine Precordillera Basin (Talacasto and Punta Negra formations) are studied. One new genus Pircawayra nov. gen., and five species (including three new: Pircawayra gigantea nov. gen. and sp., Lapazites trinodis nov. sp. and Keslingiella? teresae nov. sp.) are defined. The recorded ostracod fauna closely resembles that coeval from Bolivia and South Africa, exhibiting a remarkable endemism, not only at the genus level, but also at the species level. In addition to its low-diversity, the Malvinokaffric ostracod association is also characterized by having large, thick, coarsely ornamented and swollen valves. The similar ostracod composition from the Andean and South African basins suggests faunal exchange between these two areas. Based on the ostracod faunas, the Malvinokaffric Realm is clearly recognizable at least up to the Middle Devonian.

► Lower–Middle Devonian ostracods from Argentina were studied. ► A typical Malvinokaffric association was recognized, including new taxa. ► It is recognizable up to the Middle Devonian in the Andean region. ► The ostracod fauna is characterized by giant and thick valves. ► Biostratigraphic implications were also discussed.