Late Jurassic (Upper Kimmeridgian) Heterobranchia (Gastropoda) of the coral-facies of Saal near Kelheim and the viciniy of Nattheim (Germany)

Abstract

Forty gastropod species of the subclass Heterobranchia are described from the Upper Jurassic (Upper Kimmeridgian) reefal limestones of South Germany, including ten species in open nomenclature and further ten species of uncertain identity. Six species are new to science: Ceritella convexa sp. nov., Nerinea donosa sp. nov., Endoplocus acutus sp. nov., Endoplocus inflatus sp. nov., Pseudonerinea ? pseudomelaniformis sp. nov., and Itieroptygmatis cylindrata sp. nov. A lectotype is designated for Ptygmatis ? tornata (Quenstedt, 1852). With this final part of the study of the Late Jurassic gastropods from Saal and the Nattheim area, a total of 156 species have been reported. Of these species, 125 have been reported from Saal and 54 from the Nattheim area. Only 23 species occur in both Saal and the Nattheim area. The sample sizes (number of specimens) from Saal and the Nattheim area differ considerably and few species are shared. Diversity metrics suggest the same high diversity at both sites. The gastropod fauna from the Saal quarry has yielded particularly much new information – all new species are based on specimens from Saal. With 125 gastropod species from a single outcrop, the diversity at the Saal quarry is the highest from the Kimmeridgian worldwide. In total, up to 300 species of marine macro-invertebrates have been reported from this quarry, which is a very high point diversity. Gastropods are by far the most diverse group from Saal, which is a modern aspect of this fauna.