New unornamented siphonodellids (Conodonta) of the lower Tournaisian from the Rhenish Massif and Moravian Karst (Germany and Czech Republic)

Abstract

Conodonts of lower Tournaisian successions in the Remscheid-Altena Anticline of the Rhenish Massif (Germany) and from the Moravian Karst of the Bohemian Massif (Czech Republic) have been re-studied based on previous high-resolution conodont stratigraphy. New lower Tournaisian siphonodellids without ornamentation on the oral platform side were recorded here in carbonate pe- lagic and turbiditic settings. Siphonodella belkai, which was previously unknown in western Europe, is the most abundant species among the unornamented siphonodellids. Two morphotypes of Si. belkaias well asSi. kalvodai sp. nov. are defined herein. The new faunas occur in the jii, sandbergi, andquadruplicata conodont zones. Siphonodella kalvodai sp. nov. has its FAD in the jii Zone, and Si. belkai first occurs in the basal jii Zone in both regions. The basal jii Zone can therefore be correlated with the basal belkai Zone established in neritic and pelagic settings of the East European Platform and Uralian Mountains. The new faunas enable a more precise correlation between lower Tournaisian biozones established previously in Central, South and Western Europe, North America, China, and East European and Uralian regions. Distributional restrictions of unornamented siphonodellids indicate a subordinate ecological significance but points out their palaeogeographic provincialism, tied to the northern Palaeotethys or palaeoequatorial realm.