Fossil terrestrial and freshwater Gastropoda from the Early/Middle Miocene of Heuchlingen, Germany

The present study is a report of fossil terrestrial and freshwater gastropods from a new outcrop exposed in the 1990s in Heuchlingen (Baden-Württemberg, SW Germany). The fossils occur in the Silvana Beds of the Upper Freshwater Molasse (OSM), dating from the Early/Middle Miocene (European Land Mammal Zone MN 5). Thirty gastropod species (6 aquatic and the remainder terrestrial) were found, belonging to the families Pomatiidae, Lymnaeidae, Planorbidae, Ellobiidae, Succineidae, Cochlicopidae, Chondrinidae, Vertiginidae, Gastrocoptidae, Clausiliidae, Ferussaciidae, Subulinidae, Discidae, Zonitidae, Agriolimacidae, Helicidae, Helicodontidae, Hygromiidae, and Trissexodontidae. These fossils are used as paleoecological proxies in an actualistic genus-level analysis to present a first attempt at an environmental reconstruction of the Heuchlingen locality. The gastropod fauna points to a paleoenvironment consisting of a shallow lake (or a shallow margin of a larger lake) surrounded by humid forests and scrublands. Literature records from Heuchlingen and the nearby locality Dettingen am Albuch, as well as the surviving voucher material, are also reviewed.