New localities of four Bulgarian endemic Hydrobiidae species (Mollusca: Gastropoda: Risooidea)

New localities of Belgrandiella pussila Angelov, 1959, Belgrandiella angelovi Pintér, 1968, Bythiospeum copiosus (Angelov, 1972), and Grossuana thracica Gl er & Georgiev, 2009 were reported in Bulgaria. Some notes on the generic position of Belgrandiella angelovi and Bythiospeum copiosus were done.