Nuevos braquiópodos prodúctidos (Rhynchonelliformea, Strophomenata) del Carbonífero de la región de Nochixtlán, Oaxaca

Abstract

Fourteen species of productid brachiopods from Ixtaltepec Formation, Oaxaca State in southeast Mexico, are described. All the species and most of the genus that are reported represent first records for Mexico, in the case of Echinoconchella this is the first report of the genus for North America. The species belong to the superfamilies Echinoconchoidea (Echinoconchus zapoteco sp. nov., Echinaria knighti, Karavankina cf. fasciata, Echinoconchella elegans), Linoproductoidea (Linoproductus cf. prattenianus, Linoproductus platyumbonus, Linoproductus sp., Marginovatia minor, Marginovatia aureocollis, Marginovatia cf. pumila, Cancrinella nunduva sp. nov., Ovatia muralis and Nuanducosia sulcata, new genus and species of Subfamily Anidanthinae) and Aulostegoidea (?Sinuatella sp.). The stratigraphic distribution of E. knighti, Karavankina cf. fasciata, Linoproductus cf. prattenianus, L. platyumbonus, M. aureocollis and Marginovatia cf. pumila confirms a Pennsylvanian age (Morrowan-Desmonesian) for the strata of the middle part of Ixtaltepec Formation; the finding of Marginovatia minor and Ovatia muralis in basal strata of the formation sets a Middle-Upper Mississippian age (Chesterian) for bearing units. The fauna described has a strong similarity to species of the east-central region of the United States, similarity that confirms the existence of a connection between the two regions during the Carboniferous through a epicontinental sea.