Distribución paleogeográfica de Aseptella (Productida): Conexión entre los braquiópodos carboníferos de España y Argentina

Abstract

Aseptella is a genus of productids described from Spain (Cantabrian Mts: the Bashkirian type species A. asturica and the Visean-Arnsbergian A. beetsi) and from Argentina (A. patriciae from the Lower Permian –although a Late Carboniferous age cannot be excluded– and A. aff. patriciae, from Upper Carboniferous strata slightly higher than the Lanipustula Zone). A. beetsi, ancestor of the other species, has a weakly developed median septum in the dorsal valve interior, which is absent in the adults of A. asturica and in the Argentinian forms. The brachiopods of the Lanipustula Zone show not only relations with those from Australia and the United States but also with those from the Cantabrian Mts, especially with those forms typical of a quiet water environment, which was rather deep and therefore more obscure and colder than normal for the latitude. The rather small forms could have drifted across the Tethys –possibly as larvae entangled in seaweed– at the begining of the Late Carboniferous and have adapted to the environment that reigned in Argentina at that time.