A new record of the enigmatic mollusc Jinonicella from the Silurian of the Carnic Alps, Austria

10.3176/earth.2018.12

Alexander P. Gubanov；Jan Ove R. Ebbestad；Olga K. Bogolepova

Silurian ； Carnic Alps ； problematic mollusc ； Jinonicella ； palaeogeography.

Proceedings of the Estonian Academy of Sciences. Geology

67卷2期（2018 / 06 / 20）

158 - 164

英文

The small enigmatic mollusc Jinonicella kolebabai Pokorný, 1978 is described from the upper Silurian Cardiola Formation at the Rauchkofel Süd section of the Carnic Alps, Austria. The associated conodonts suggest a late Ludlow (Ludfordian) Polygnathoides siluricus conodont Zone. Previous Silurian records of Jinonicella are known from the Wenlock to Ludlow of the Czech Republic, USA, Gotland of Sweden and the Carnic Alps of Austria. The wide distribution of this taxon across different climatic zones and widely separated areas in the Silurian is problematic, and it is unclear whether Jinonicella was present in high-latitude areas before the end-Ordovician cooling and mass extinction or was dispersed during the Silurian. Possible planktotrophy in Jinonicella and Silurian ocean circulation patterns may explain the dispersal, but within the framework of current palaeogeographical reconstructions the model does not adequately explain an equatorial to polar distribution of other contemporaneous benthic faunas from these areas.