The palaeobiogeographic significance of the Nötsch area (Austria) during the Middle and Late Mississippian based on rugose corals

Abstract

The Carboniferous of Nötsch (South Austria) is composed of three formations: the Erlachgraben Formation, the Badstub Breccia, and the Nötsch Formation, that yielded abundant corals, several of them being new for that region. The assemblage is composed of 11 rugose coral species (Siphonophyllia sp., Pseudozaphrentoides juddi, Lublinophyllum? sp., Dibunophyllum bipartitum, Arachnolasma cylindrica, Palaeosmilia murchisoni, Aulokoninckophyllum carinatum, Siphonodendron martini, Diphyphyllum furcatum, Solenodendron furcatum, and Solenodendron horsfieldi), two tabulate species (Multithecopora sp. and Palaeacis sp.) and one heterocoral species (Hexaphyllia mirabilis). In addition, five rugosans that are not in our collection have been identified by previous authors (Clisiophyllum sp., Pseudozaphrentoides sp., Caninia sp., “Palaeosmilia isae”, and Lophophyllidium sp.). The rugose and tabulate species are described and figured. A palaeobiogeographic analysis comparing the Mississippian assemblages from Nötsch and other Austrian outcrops with other domains in Central Europe has been performed using hierarchical clustering with Simpson and Dice similarity indices. The statistical comparison of the rugose coral assemblages at the genus level allows a better perception of the distribution of the shallow water carbonate platforms in that part of the Western Palaeotethys during the Visean and Serpukhovian. The results are incorporated in a schematic palaeogeographical map of the studied area for the late Visean.