A Late Ordovician conodont fauna from the Uqua Section, Carnic Alps, Italy

The Uqua Section of the western Carnic Alps (Italy) represents the reference succession where conodont studies in the Ordovician of southern Europe were initated. The pioneer paper by Serpagli (1967) described the fauna there recovered as morphospecies, in use at that time, with the introduction of several new taxa that were carefully designated but illustrated only with drawings. A biostratigraphically diagnostic conodont fauna of more than 1500 specimens, preliminarily reported by Vai & Spalletta (1980) but never described, is herein analyzed and figured for the first time. The Amorphognathus ordovicicus Biozone is represented by a well-preserved conodont assemblage of 15 species belonging to 15 genera. Common taxa are representatives of Hamarodus brevirameus, Scabbardella altipes and Amorphognathus ordovicicus. They co-occur with less common species including Dapsilodus mutatus, Eocarniodus gracilis and Plectodina alpina. This fauna, documenting the Hamarodus brevirameus-Dapsilodus mutatus-Scabbardella altipes biofacies, is strikingly similar to other occurrences elsewhere in the Carnic Alps. The uppermost calcareous blocks, associated with an Hirnantian brachiopod fauna, do not vary significantly in conodont content from the lower levels. The Uqua Section does not reveal the typical Hirnantian conodont signature, indicated by the genera Sagittodontina and Istorinus, reported in the Carnic Alps only from the Cellon Section.