Unraveling late Pennsylvanian brachiopod assemblages from the San Rafael Basin (Argentina): Biostratigraphic implications to southwestern Gondwana

New and previous fossil remains resulting biostratigraphy of the El Imperial Formation at Arroyo del Imperial, Quebrada de La Horqueta, Cañón Atuel key sections are analyzed, while faunal relationships among them clarified. Two diachronnous faunas, pTS TSAIII associations, relatives to Tivertonia-Streptorhynchus assemblage recognized constrained early late Bashkirian Moscovian ages, respectively. These age assignments supported by statistical analyses available palynological radiometric dating. Previous mentions brachiopods from Horqueta elucidated with identification Buxtonia cf. riojanae (Leanza), Streptorhynchus inaequiornatus Leanza, Spiriferellina? sp., Septosyringothyris (Precosyringothyris) aff. jaguelensis Lech, feruglioi (Amos), Saltospirifer guevarai Cisterna Archbold Pericospira sp. A new marine fauna upper part section (Cabecera Member) is reported. It includes Argentiella A. stappenbecki Archbold, Sterren, Oehlertella annae (Feruglio), Orbiculoidea saltensis Reed, Calytrixia piersoni Taboada, Coolkilella aredesi Costatumulus Septosyringothyris? bio-chronostratigraphic correlation scheme, including lithostratigraphic units biozones central-western Argentina updated.