First record of an autochthonous community of fluviatile freshwater molluscs from the Middle/Late Miocene Upper Freshwater Molasse (southern Germany)

The discovery of an autochthonous well-preserved assemblage from Middle/Late Miocene fluviatile deposits within the Upper Freshwater Molasse (Obere SuBwassermolasse) at Hammerschmiede north of Kaufbeuren (Allgau region, southern Germany) provides the rare opportunity to assess both composition and palaeoecology of a typical Miocene northern alpine foreland river mollusc community. Three species of bivalves, i.e. Margaritifera (Pseudunio) flabellata (GOLDFUSS), Sphaerium (Amesoda) rivicola (LAMARCK), and Pisidium (Pisidium) amnicum (PFEIFFER), accompanied by the gastropods Borysthenia sp., Bithynia sp. 1, and Bithynia sp. 2, are described. The taxonomy of Margaritifera (Pseudunio) flabellata is updated, and several nominal subspecies are rejected. Sphaerium (Amesoda) rivicola is reported for the first time from the Upper Freshwater Molasse. The eastern to middle European valvatid genus Borysthenia is first recorded from the Miocene. Most of these taxa are adapted to hard water and a well-oxygenated, sandy fluvial habitat and thus provide an excellent example for a common mollusc community of the Upper Freshwater Molasse.