The Middle Ordovician Jinonicella (Mollusca) from Belarus and Ukraine

The oldest known specimens of the enigmatic mollusc Jinonicella kolebabai Pokorný, 1978 are redescribed from Middle Ordovician strata of Ukraine and Belarus. The phosphatic internal moulds preserve imprints of growth lines, hitherto only documented in Silurian specimens. The persistent distribution of Jinonicella in the Baltoscandian basin of the Russian Platform suggests that this was the centre of origin of this taxon. During the Silurian, Jinonicella inhabited Siberia and Laurentia, and the smaller European terranes of Bohemia and the Carnic Alps. In the Devonian, Jinonicella is reported from Laurentia, Bohemia and the Rhenish Massif.