Nuevos registros de Braquiópodos y consideraciones sobre las faunas de Tivertoniastreptorhynchus (Moscoviano) y Costatumulus amosi (Pérmico temprano) del oeste argentino: reexamen de las secciones clave de las Quebradas Agua del Jagüel y Santa Elena

The brachiopod Coolkilella aredesi sp. nov. and Calytrixia piersoni sp. nov. are proposed on the basis of specimens from the Del Salto, Río del Peñón and Agua del Jagüel formations. Their biostratigraphic implications are discussed together with new records of Septosyringothyris (Precosyringothyris) jaguelensis Lech and Streptorhynchus inaequiornatus Leanza at the top of the latter unit. The stratigraphic record, paleontological content and age of both the Tivertonia-Streptorhynchus assemblage (Moscovian) and the younger Costatumulus amosi fauna (Sakmarian–Artinskian) were reviewed and assessed based on outcrops at Quebrada Agua del Jagüel and Quebrada Santa Elena. Faunal content confirms the most recent stratigraphic, biostratigraphic and paleoclimatic frameworks. These a diachronic nature of the Agua del Jagüel and Cordón del Jagüel formations, supporting the absence of an early Permian glacial event in western Argentina.Se proponen las nuevas especies de braquiópodos Coolkilella aredesi sp. nov. y Calytrixia piersoni sp. nov. sobre la base de especímenes provenientes de las formaciones Del Salto, Río del Peñón y Agua del Jagüel. Se analizan sus implicancias bioestratigraficas junto al significado de nuevos registros de Septosyringothyris (Precosyringothyris) jaguelensis Lech y Streptorhynchus inaequiornatus Leanza en el techo de la última unidad mencionada. Se revisan y precisan el registro estratigráfico, contenido paleontológico y edades de la asociación de Tivertonia-Streptorhynchus (Moscoviano) y de la fauna más joven de Costatumulus amosi (Sakmariano—Artinskiano) en los afloramientos de las Quebradas de Agua de Jagüel y Santa Elena. El contenido faunístico permite corroborar los más recientes esquemas estratigráficos, bioestratigráficos y paleoclimáticos, reconociendo las formaciones Agua del Jagüel y Cordón del Jagüel como unidades diacrónicas y desestimando a su vez la existencia de un evento glacial Pérmico en el oeste de Argentina.Fil: Taboada, Arturo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Laboratorio de Investigaciones en Evolución y Biodiversidad; Argentin

An early Permian brachiopod–gastropod fauna from the Calytrix Formation, Barbwire Terrace, Canning Basin, Western Australia

A small brachiopod–gastropod fauna from a core close to the base of the Calytrix Formation within the Grant Group includes the brachiopods Altiplecus decipiens (Hosking), Myodelthyrium dickinsi (Thomas), Brachythyrinella narsarhensis (Reed), Neochonetes (Sommeriella) obrieni Archbold, Tivertonia barbwirensis sp. nov. and the gastropod Peruvispira canningensis sp. nov. The fauna has affinities with that of the late Sakmarian‒early Artinskian Nura Nura Member directly overlying the Grant Group in other parts of the basin but, as with all lower Cisuralian (and Pennsylvanian) glacial strata in Western Australia, its precise age remains poorly constrained, especially in terms of correlation to international stages. Although the Calytrix fauna lies within the Pseudoreticulatispora confluens Palynozone, the only real constraint on its age (and that of the associated glacially influenced strata) is from Sakmarian (Sterlitamakian) and stratigraphically younger faunas. A brief review of radiometric ages from correlative strata elsewhere in Gondwana shows that those ages need to be updated. The presence of Asselian strata and the position of the Carboniferous‒Permian boundary remain unclear in Western Australia.Arturo César Taboada [[email protected]], CONICET-Laboratorio de Investigaciones en Evolución y Biodiversidad (LIEB), Facultad de Ciencias Naturales, Sede Esquel, Universidad Nacional de la Patagonia ‘San Juan Bosco’, Edificio de Aulas, Ruta Nacional 259, km. 16,5, Esquel U9200, Chubut, Argentina; Arthur Mory [[email protected]], Geological Survey of Western Australia, 100 Plain Street, East Perth, WA 6004, School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; Guang R. Shi [[email protected]], School of Life and Environmental Sciences, Deakin University, Melbourne Burwood Campus, 221 Burwood Highway, Burwood, Victoria 3125, Australia; David W. Haig [[email protected]], School of Earth and Environment (M004), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; María Karina Pinilla [[email protected]], División Paleozoología Invertebrados, Museo de Ciencias Naturales de La Plata, Paseo del Bosque s/n, 1900 La Plata, Buenos Aires, Argentina