Clessin, 1882 : 119 gracilis Brusina 1886 : 53 Clessin 1887 : 628 Karaman 1935 : 53 Schütt 1975 : 1 Phylogenetic relationships of the Balkan Moitessieriidae (Caenogastropoda: Truncatelloidea) Hofman, Sebastian Rysiewska, Aleksandra Osikowski, Artur Grego, Jozef Sket, Boris Prevorčnik, Simona Zagmajster, Maja Falniowski, Andrzej Zootaxa 2018 2018-09-28 4486 3 311 339 (Clessin, 1882) Clessin 1882 [151,544,1196,1222] Gastropoda Hydrobiidae Iglica GBIF Animalia Littorinimorpha 18 329 Mollusca species gracilis    Vitrella  gracilis  Clessin, 1882: 119, pl. 1; fig. 6.   Vitrella gracilis—  Brusina 1886: 53.    Vitrella gracilis—  Clessin 1887: 628, Abb. 422.    Iglica gracilis—  Karaman 1935: 53.    Iglica gracilis—  Schütt 1975: 1–14.   Iglica gracilis, det. Kuščer—De Mattia 2005: fig. 55  “ Iglica” gracilis— De Mattia 2007: fig. 5.   Material examined:ZMUJ2108–ZMUJ2113, ZMUJ 2134–2136  Clessin (1882)described this species from “Krain (leg. Hofmann et Robic)”; only empty shells were available. Despite our efforts it has been impossible to find any information on the typespecimens. The species is endemic to Sloveniaand inhabits caves and springs in the river Krka basin ( Karaman 1935, Schütt 1975, Bole & Velkovrh 1986, Bole 1992, Bole et al.1993, Bole & Slapnik 1997, Sket & Velkovrh 2002, De Mattia 2007, Seddon 2010a) to the junction of the Krka with the Sava River, that covers much of the catchment of the river Krka ( De Mattia 2007. Our specimens were obtained from interstitial waters pumped from sediments of the river Sava, Čatež ob Savi, Slovenia. Our specimens have been collected within the geographic range given by Schütt (1975)and De Mattia (2007), and the shells of our specimens present character states described by Clessin (1882)and resemble the ones of  I. gracilispresented by Clessin (1882), Schütt (1975)and De Mattia (2007).