Early Miocene land and freshwater gastropods from the karst fissure filling Tomerdingen 1 (southern Germany)

Abstract

The mollusc fauna recovered from the fissure filling Tomerdingen 1 (southern Germany, 11 km NW Ulm) consists of six species of freshwater and land gastropods which are revised and figured. All except Triptychia tomerdingensis n. sp. (Clausilioidea, Filholididae) were already known from the Ulm Beds and Ehingen Beds in the area. The mammals of Tomerdingen 1 have been assigned to the early part of mammal zone MN 1; it is assumed that the molluscs, which occurred in a different, mammal-free rock matrix, have a similar age. The faunal assemblage of Tomerdingen 1 represents a new local mollusc assemblage zone, characterized by the presence of Triptychia tomerdingensis n. sp. Ties of the mollusc assemblages of the Ulm Beds and underlying Ehingen Beds with the mammal biozonation are discussed. The Tomerdingen assemblage is overlain by the Eggingen assemblage which is associated with mammal subzone MN 2a, possibly extending into late MN 1, and includes the majority of recorded mollusc occurrences; Tomerdingen is preceded by the Ehingen assemblage, from which no mammal evidence is known.