Fossil gastropods from Miocene Lake Randeck Maar and its hinterland (SW Germany)

The Randeck Maar lake sediments from southwestern Germany were deposited during the late Early to early Middle Miocene (mammal zone MN 5). Although historically well known as an important fossil Lagerstätte, there are few works that have dealt specifically with the fossil gastropods (no bivalves have ever been found). A revision is presented herein of all the material available from the site, both from historical museum collections and from new excavations, figuring much of these gastropods for the first time. The snail fauna of the Randeck Maar now comprises a total 32 continental gastropod species, among which only four are freshwater: Lymnaea cf.dilatata, Ferrissia deperdita, Gyraulus kleini and Planorbarius cornu. The terrestrial snail fauna consist mostly of land-dwelling pulmonates, being dominated by the following species: Pomatias conicus (the only operculate snail in the fauna), Cochlicopa loxostoma, Granaria sp. and Praeoestophorella phacodes. Finally, the following species are reported for the first time from Randeck Maar: Clausiliinae indet., Triptychia kleini, Palaeotachea renevieri, Deroceras sp., Milax sp., Gastrocopta sandbergeri, Testacella zellii. Such a diverse snail fauna might help elucidate paleoecological questions regarding the Randek Maar lake and its hinterland.