Distribution.The species is distributed throughout Europe and almost all West Siberia (Beriozkina et al., 1995). In some parts of its range it is rare or very rare (e. g. in Poland, Falniowski et al., 2004). In Ukraine the species is known from limited number of locations in the west part and in Steppe zone of the country (e. g. Anistratenko, Chernogorenko, 1989; Anistratenko, Stadnichenko, 1995). Recently it was mentioned as regionally new species for the Transcarpathian Region of Ukraine (Anistratenko et al., 2018). Since B. troschelii is recorded here only one time (locality 13) we suggest it is rare species in the Ukrainian Transcarpathia.

R e m a r k s. Some authors (e. g. Welter-Schultes, 2012) use the name Bithynia transsilvanica (Bielz) for this species while others (Glöer, 2002; Falniowski et al.,2004) consider the valid name is B.troschelii.In 1995 Beriozkina et al.(1995) established a distinct generic name Opisthorchophorus for Paludina troschelii Paasch, 1842 and few others nominal species with peg-top-shaped shell having convex whorls separated by a deep suture. By the shell shape the specimens we found in Transcarpathia (fig. 3, 6) demonstrate a close resemblance to ‘ O. hispanicus’ sensu Beriozkina et al.(1995: fig.4, E).However we are not sure if ‘ O. hispanicus’ might represent a distinctinct species or is just a morphotype and prefer name the snails found as B. troschelii. As in the whole area of its distribution the species lives in Transcarpathia in temporary and semipermanent waterbodies, e.g. in small shallow artificial pools.