Opole (Poland) - a key locality for middle Miocene terrestrial mollusc faunas

Abstract

We describe an early middle Miocene (late Langhian) terrestrial mollusc fauna from Nowa Wieś Królewska at Opole in Silesia (Poland). This survey is based on the rich collection stored in the Natural History Museum in Vienna and repre- sents the first revision of this classical fauna. The assemblage is extraordinarily diverse and comprises 82 gastropod spe- cies and one bivalve species. About 56% of the taxa are known so far only from Nowa Wieś Królewska, emphasizing the preeminent position of this fauna within the European Neogene. The fauna reveals taxonomic affinities with early and early middle Miocene faunas. Stratigraphic overlap of several species and genera would suggest a correlation with the mammal biozone MN 5; integrating mammal data, however, indicates correlation with the biozone MN 6. This discrep- ancy is explained best by the lack of other adequately revised European MN 6 mollusc faunas. Consequently, the fauna from Nowa Wieś Królewska is proposed here as type of a MN 6 mollusc fauna in Central Europe. As such, this fauna represents the best-documented terrestrial mollusc fauna from the late Miocene Climate Optimum. Semi-quantitative abundance data of the terrestrial gastropods suggests the presence of ephemeral ponds and fens that formed on Cret- aceous limestones, surrounded by forested environments with leaf litter and dead wood. Occidentina gen. nov., Mennoia gen. nov., Neubertella gen. nov. and Eurocystina gen. nov. are described as new genera. Martinietta kadolskyi sp. nov., Carychium stworzewiczae sp. nov., Gastrocopta (Albinula) polonica sp. nov., Leiostyla piserai sp. nov., Vertigo antipygmaea sp. nov., Mennoia sculpturata sp. nov., Neubertella pulchra sp. nov., Aegopinella depressula sp. nov., Eurocystina nordsiecki sp. nov. and Vitrea angustaeumbilicata sp. nov. are introduced as new species.