Arturo César Taboada

The coupled occurrence of Cimmeriella-Jakutoproductus (Brachiopoda: Productidina) in Patagonia: implications for Early Permian high to middle paleolatitudinal correlations and paleoclimatic reconstruction

The brachiopod species Jakutoproductus sabattiniae sp. nov. and Cimmeriella willi sp. nov. from the Cisuralian deposits of the Tepuel-Genoa basin are described here. Biostratigraphy and stratigraphy of the uppermost section of the Tepuel Group (Mojon de Hierro and Rio Genoa formations) are analyzed and a distinctive faunal succession is recognized: the Cimmeriella and Jakutoproductus faunal assemblages of late Sakmarian (Sterlitamakian) and early Artinskian estimated ages, respectively. The lower Permian correlations of these faunal occurrences and the chronology of mostly early Permian glacial episodes between Western and Eastern Argentina with Patagonia are discussed. The coupled Verchojania-Jakutoproductus, Eurydesma-Cimmeriella and Cimmeriella-Jakutoproductus faunal records have been used as a tool for the correlation of early Permian marine sequences from the high to middle paleolatidudinal settings of both hemispheres.

Yagonia Roberts (Brachiopoda: Chonetidina) from the Malimán Formation, Lower Carboniferous of western Argentina: palaeobiogeographical implications

A new anoplid chonetid species, Yagonia furquei sp. nov., is described from the Lower Carboniferous (late Tournaisian–early Viséan) Malimán Formation of western Argentina. The associated temperate ‘Malimanian’ fauna is suggested to indicate an initial biotic segregation that took place in western Gondwana (southwestern South America), a palaeobiogeographic event that predated the late Viséan global cooling and associated major palaeolatitudinal biotic differentiation. Occurrences of Yagonia are here interpreted as evidence of a ‘south to north’ faunal migration pathway, here named the Austropanthalassic–Rheic oceanic corridor, established in western Gondwana during the late Early Carboniferous.

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

Taboada, A.C., Mory, A.J., Shi, G.R., Haig, D.W. & Pinilla, M.K., 12.11.2014. An Early Permian brachiopod–gastropod fauna from the Calytrix Formation, Barbwire Terrace, Canning Basin, Western Australia. Alcheringa 39, xxx–xxx. ISSN 0311-5518 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 [ataboada@unpata.edu.ar], 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 [arthur.mory@dmp.wa.gov.au], 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 [grshi@deakin.edu.au], School of Life and Environmental Sciences, Deakin University, Melbourne Burwood Campus, 221 Burwood Highway, Burwood, Victoria 3125, Australia; David W. Haig [david.haig@uwa.edu.au], School of Earth and Environment (M004), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; María Karina Pinilla [mkpinilla@fcnym.unlp.edu.ar], División Paleozoología Invertebrados, Museo de Ciencias Naturales de La Plata, Paseo del Bosque s/n, 1900 La Plata, Buenos Aires, Argentina.

New Brachiopod records and considerations on the Tivertonia-Streptorhynchus (Moscovian) and Costatumulus amosi (Sakmarian–Artinskian) Faunas from Western Argentina: The Key Sections at Quebrada agua del Jaguel and Quebrada Santa Elena Revisited

Abstract. 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 recognize 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.