In the present study, a distinctive lineage of lymnaeid gastropods from the deep-water deposits of the Late Miocene Lake Pannon (Central Europe) is revised. The examined material includes specimens from museum collections as well as newly collected fossils from different parts of the Pannonian Basin System. During the past 150 years, at least 30 deep-water lymnaeid species assigned to ten genera have been described from the Lake Pannon deposits; however, our examination of more than 700 specimens shows that these records represent only 11 species belonging to five genera. Lectotypes are designated for four species for which earlier type designations were invalid. Species belonging to the Radix–Velutinopsis–Undulotheca–Provalenciennesia–Valenciennius lineage form one of the most extraordinary molluscan groups of Lake Pannon. Their interest lies in their distinctive shell morphology – large (sometimes exceeding 10 cm), wide, thin, cap-like shells with reduced coiling and undulated ribs – and their deep-water mode of life, supported by occurrences in drill cores and bathymetrically calibrated by seismic sections. This taxonomic revision enables the lineage to be applied in deep-water biostratigraphy of Lake Pannon sediments. Based on first appearance datums of key lineage species and associated taxa from other mollusc groups, four new lineage zones are proposed, integrated with the established deep-water mollusc biozonation. In contrast to the anagenetic evolutionary patterns typical of biostratigraphically important Lake Pannon bivalves, this gastropod lineage shows predominantly anacladogenetic speciation.
DOI: 10.3897/zookeys.1282.186967
Publication Date: 2026-06-12