New conodont faunas from the Late Ordovician of the Central Carnic Alps, Austria

Conodont faunas recovered from both the Uggwa and Wolayer limestones of the Central Carnic Alps, Austria documented unequivocally the Amorphognathus ordovicicus Zone. Hamarodus europaeus (Serpagli, 1967), Scabbardella altipes (Henningsmoen, 1948) and Walliserodus amplissimus (Serpagli, 1967) represent some of the characteristic species. The association closely matches in composition and age the conodont material described on the Italian side of the Alps. A younger fauna was recovered immediately above a well-known brachiopod Hirnantia Fauna in the Cellon section, a classic reference for Silurian conodont biostratigraphy. The association keeps a clear Ordovician aspect having its markers in A. cf. A. ordovicicus Branson and Mehl. 1933 and A. lindstroemi (Serpagli, 1967). Elements of "Dichodella-Birksfeldia", possibly corresponding to the distinctive North American Gamachian genus Gamachignathus, are well represented. Taxa previously common in colder regimes, such as Sagittodontina and Istorinus, are also present. The abundance and moderate diversity of this fauna, composed of about twenty species, allow a first significant definition of the Hirnantian conodont fauna from the Atlantic Faunal Region.