Ostracod faunas from the Late Mississippian–Early Pennsylvanian, Calingasta–Uspallata Basin, central west Argentina: new records from glacial–postglacial successions

Ostracods from the late Mississippian–early Pennsylvanian (late Serpukhovian–Bashkirian) from the Calingasta–Uspallata Basin, Precordillera Argentina, are studied for the first time. The analyzed successions (Hoyada Verde, El Paso, Leoncito, and Yalguaraz formations) document the most widespread glacial event in southwestern Gondwana during the Late Paleozoic Ice Age. One new species, Aechmina cuyanensis new species, is defined, and seven species are described, two of which are new records for South America. The distribution of Carboniferous ostracods in the Argentine basins (Calingasta–Uspallata, Río Blanco, and Tepuel–Genoa) is discussed, highlighting the interesting record of this fauna in levels between or below diamictites and its absence in the mudstone interval with no evidence of glaciation. The association is characterized by ornamented palaeocopids, one binodicopid, and some metacopid species corresponding to the Assemblage III of the Eifelian Mega-Assemblage, indicating a slightly hypoxic and very calm environment between the fair-weather wave base and the storm wave base. UUID: https://zoobank.org/68fda8dc-be98-4a03-b369-a696b7d7ad99