Hydrobia Hartmann 1821, s.l.

Genus Hydrobia Hartmann, 1821 s.l. Type species: Cyclostoma acutum Draparnaud, 1805; by original designation. Remarks: The type species of this genus is an extant brackish water species distributed in the coastal region of the western Mediterranean (Wilke et al. 2000). It is characterized by a smooth, conical shell with a shell height of ca. 2.5–3 mm (Giusti et al. 1998). The genus is considered to have diverged from its closest relatives in the Early to Middle Miocene (ca. 10–20 Mya) (Delicado et al. 2023). Hydrobia has traditionally served as a wastebasket taxon for Cenozoic and Mesozoic species (MolluscaBase 2026). Currently 220 species are assigned to this genus, the majority of which (207 species) are known only from the fossil record. While there is evidence for morphological conservatism from the Cretaceous until today, resulting in genera living for a hundred million years (Hirano et al. 2019), many of these classifications are probably the result of too few diagnostic characters. The same applies to the case of Hydrobia veszprimica, which is retained in the genus only tentatively due to the paucity of diagnostic characters.