Fish otoliths from the basal Oligocene Viborg Formation in Denmark

The Viborg Formation is the lowest part of the early Oligocene in Denmark and represents the upper part of nannoplankton zone NP21. Here we describe a small assemblage of otoliths from the Viborg Formation obtained from five localities that yielded 88 specimens of nine species. The composition of the otolith-based f ish species is transitional between the terminal Eocene (Priabonian) faunas from the Latdorf Formation of northern Germany and its equivalents and the middle and upper Rupelian. The Viborg otolith association witnessed the first arrivals of the subsequently dominant Gadidae (Trisopterus elegans) and the migration of certain species of the merlucciid genus Palaeogadus from the Eastern Paratethys through the Polish gateway. Furthermore, the otoliths from the Viborg Formation f ill an important gap in the previous knowledge of late Eocene and early Oligocene otolith associations in the North Sea Basin and thus facilitate some refinement of their biostratigraphic usage.