New findings of the little known crenobiotic snail Bythinella serborientalis Radoman, 1978 (Gastropoda: Truncatelloidea, Bythinellidae) with notes on its morphological variability

We report on two new sites for the little known crenobiotic snail Bythinella serborientalis Radoman, 1978, based on molecular and morphological analyses. A recent record of this species from western Serbia is discussed and corrected. In addition, we provide information about the intraspecific variability of B. serborientalis, both in terms of shell and penial morphology. In general, the morphological variability is observed as quite high and there are no stable characters which could distinguish this species from its congeners. Therefore, DNA analyses should be used in order to complement morphological descriptions.