Litthabitella chilodia (Westerlund, 1886) in Italy (Gastropoda : Prosobranchia : Hydrobiidae)

Bythinella opaca pollinensis Bacci (1952) is herein regarded as a junior sy nonym of Litthabitella chilodia (Westerlund, 1886). Litthabitella Boeters, 1970, is a genus of hydrobiid prosobranchs characterized by: penis apex bif id, divided into apical lobe and tip of penis proper; one-four irregularly shaped glandular swellings on ventral side of apical lobe and penis close t o base of lobe; well developed bursa copulatrix; two seminal receptacles, p roximal (RS2) smaller than distal (RS1). At present it includes only the ty pe species L. chilodia present in the western Balkans, Ionian islands and s outhern Italy. Paludinella elliptica Paladilhe, 1874, from the Pyrenees, on ce attributed to Litthabitella, still has uncertain taxonomic relationships . The current subdivision of L. chilodia into L. chilodia chilodia and L. c hilodia ionica (Schutt, 1980) is rejected. Examination of the type material of the latter from the island of Corfu, showed that it includes two differ ent taxa, one of which (the holotype) is a species of Belgrandia and the ot her L. chilodia. Due to the absence of anatomical data, the taxonomic statu s of Belgrandia ionica (Schutt, 1980) is still uncertain. Italian populatio ns of L. chilodia are characterized by wide variation in shell shape and si ze and one population, living in a small brook in the cave Grotta del Tasso in Apulia, has two distinct coexisting shell morphs, almost without interm ediates.