New localities of four Bulgarian endemic Hydrobiidae species (Mollusca: Gastropoda: Risooidea) Author Georgiev, Dilian text ZooNotes 2011 2011-02-04 2011 16 1 4 journal article 300110 10.5281/zenodo.12806660 ff6f3c18-6df8-4c53-9d87-e535c82f5cb8 1313-9916 12806660 Belgrandiella pussila Angelov, 1959 Distribution in Bulgaria : Species known only from the type locality – the source of Petreska River, near Lakatnik town, Stara Planina Mts. ( Angelov 1959 , 2000 ). Material examined: 6 shells (1 fresh, 5 old), 07.03.2010 , Temnata Dupka cave, Lakatnik town, UTM FN96, D. Georgiev leg. Diagnosis: The distinctive characters of this species discerning it from the rest of the Bulgarian Belgrandiella are the cylindrical shell with obtuse apex and the oval small aperture ( Angelov 1959 ). Its shell is smaller and its morphology is very different from these ones of the two other freshwater snails found in this cave ( Wagner 1927 ): Belgrandiella hessei Wagner, 1927 and Bythiospeum bureschi ( Wagner, 1927 ) (= Paladilhiopsis bureschi Wagner, 1927 ). From the first species it differs by the smaller aperture having a simple lip, cylindrical shell, obtuse apex, and flatter whorls, and from the second – by the smaller number of whorls, having not so deep suture, its cylindrical shell, and simple aperture lip ( Fig. 1 ). Other associated molluscs: In the deposits of the river in Temnata Dupka cave studied we also collected and one juvenile shell of a freshwater mussel from the genus Pisidium Pfeiffer, 1821 .