When morphology meets molecules: diversity of dart-bearing Hygromia Risso, 1826 land snails (Gastropoda: Hygromiidae).

This article focuses on the taxonomic revision and species diversity assessment of the European land snail genus Hygromia using an integrative approach combining shell and genital morphology, including love dart characteristics, with genetic analyses of mitochondrial and nuclear DNA from 205 specimens across 90 European localities. The study confirms the existence of two monophyletic subgenera—Hygromia sensu stricto (s.s.) with the widespread species Hygromia cinctella, and Riedelia, which includes Hygromia limbata sensu stricto and its subspecies H. limbata hylonomia, Hygromia tassyi (synonymous with Hygromia gofasi), and the newly described species Hygromia pyrenaica. Morphological shell characters alone were insufficient for reliable species identification, whereas love dart morphology provided significant taxonomic value. The findings reveal a complex evolutionary history with several narrowly distributed endemic taxa primarily in the Pyrenees region, highlighting the need for further population genetic studies to clarify species boundaries and biogeography within the genus.