Middle and upper Devonian chitinozoan biostratigraphy of the paraná basin in Brazil and Paraguay

Abstract

Chitinozoans from Middle and Upper Devonian strata have been investigated from the Paraná Basin in southern Brazil and eastern Paraguay. These sequences are present in the Alto Garças (north) and Apucarana (south) sub‐basins in Brazil, and the “East Paraguay Sub‐basin”; in eastern Paraguay. Marine communication between the sub‐basins was established during the early Givetian. Of the 49 chitinozoan species encountered, 28 species are retained in open nomenclature, and Ancyrochitina simplex is newly described. A chitinozoan biozonation, with five zones, is proposed for the investigated interval. The zones are from oldest to youngest: concurrent range zone of Alpenachitina eisenacki and Spinachitina biconstricta (late Eifelian?‐early Givetian); the interval range zone of Ancyrochitina taouratinensis (latest early‐middle Givetian); concurrent range zone of Fungochitina pilosa and Ancyrochitina langei (late Givetian); concurrent range zone of Hoegisphaera glabra and Ramochitina derbyi (early Frasnian); and total range zone of Lagenochitinaavelinoi (early late Frasnian).