Multielement Conodonts from the Upper Ordovician of the Siberian Platform

The multielement apparatuses of conodonts from the upper part of the Dzherome Formation (Baksanian and Dolborian regional stages) of the Upper Ordovician strata exposed along the Moyero and Moyerokan rivers on the Siberian Platform have been reconstructed for the first time. Multielement apparatuses include 32 formal species represented by large hyaline coniform conodont elements, described by T.A. Moskalenko in the 1970s–1980s. A new genus Acanthodistacodus gen. nov. has been described. The apparatus of the Acanthodistacodus, Dolborodina, and Acanthodina tentatively consists of 17 elements that can be classified into four morphotypes: dolaborate, quadricostate, quinquicostate, and bipennate elements. The apparatus of Ac. festus Moskalenko includes at least 13 dolaborate and bipennate elements. The species of Acanthodistacodus and Acanthodina are probably endemic to the Siberian Platform; Ac. festus Moskalenko, 1973, Dol. juktaliensis (Moskalenko, 1973), and Dol. striata Moskalenko, 2003 have also been found in northeastern Russia, which indicates that this region is biogeographically similar to the Siberian Platform.