Two new stygobiotic species of Horatia Bourguignat, 1887 (Hydrobiidae) from Croatia

Abstract

In this paper we describe two new species of the freshwater snails of genus Horatia. A new stygobiotic species of Horatia Bourguignat, 1887 is described from Izvor Beguša in Croatia. It occurs in sympatry with the crenobiotic H. klecakiana Bourguignat, 1887, but is morphologically and molecularly distinct. It is characterized by the terminal part of the body whorl separated from the columella, and neither eyes nor any pigment on the soft parts. It is a stygobiont gastropod, known so far only from one living specimen and several empty shells, thus its soft part morphology and anatomy remain unknown. Another new species of stygobiotic Horatia was found inside the cave Mali Rumin, its description is based solely on numerous empty shells from the cave sediments.