Vitrea diaphana (Studer, 1829)

Kolev, Iltcho, Georgiev, Dilian & Dedov, Ivaylo, 2015, Malacofauna of the catchment area of Rusenski Lom River (North Bulgaria), ZooNotes 2015 (76), pp. 1-12 : 11

Vitrea diaphana (Studer, 1829)

12.05.2014, vill. Krepcha;

Vitrea pygmaea (Boettger, 1880)

02.11.2012, deposits of Cherni Lom River, “Varbovska Vodenitsa” area;

Vitrea subrimata (Reinhardt, 1871)

05.10.2011, Russe ; 01.01.2012, vill. Katselovo ; 29.09.2012 ,, vill. Basarbovo ; 02.11.2012, vill. Karan Varbovka ; 08.10.2013, vill. Pepelina ; 27.03.2014, vill. Nisovo ;

Xerolenta obvia (Menke, 1828)

26.5.2007, NE- border of vill. Tabachka , at limestone rocks beside cave ; 05.10.2011, under a rock arc, Russe , at the big bridge above Rusenski Lom River ; 26.12.2010, vill. Katselovo ; 29.10.2011, vill. Bazovets ; 29.11.2011, Russe ; 15.12.2011, vill. Ostritsa ; 21.04.2012, vill. Garchinovo , near watersource ; 01.05.2012, vill. Shtraklevo ; 08.08.2012, vill. Pisanets ; 19.10.2012, Stalpishte area , the hills above the fishponds ; 19.10.2012, Stalpishte, the gorge going to Trastenik ; 30.04.2013, vill. Zahari Stoyanovo ; CS – LC ;

Zebrina detrita (O. F. Müller, 1774)

26.5.2007, NE- border of vill. Tabachka, at limestone rocks beside cave; 24.03.2012, vill. Ivanovo, above “Pismata” (nest of Egyptian vulture); 19.10.2012, Stalpishte area, the hills above the fishponds;

Zonitoides nitidus (O. F. Müller, 1774)

04.07.2006, deposits of Beli Lom River near vill. Ivanovo;

At least 120 mollusc species were registered at the area (freshwater clams - 11, freshwater snails - 31, and terrestrial snails - 78 species). Some of them are still with unclear taxonomic statute as for example Bythiospeum sp. , and the species from the complexes of M. cartusiana , Limax spp.

Two bivalve species were confirmed for the region ( U. tumidus , U. crassus ), 9 are new findings. From fresh-water gastropods 12 previously reported species were confirmed for the region ( E. daudebartii acicularis , E. esperi , G. truncatula , G. laevis , H. holandrii , L. naticoides , R. auricularia , Ph. acuta , T. danubialis , T. fluviatilis , T. transversalis , V. piscinalis ) and 19 are new findings.

From the terrestrial gastropods 7 previously reported species were confirmed for the region ( A. minor , A. biplicata , B. varnensis , L. plicata , L. maximus , M. cartusiana , X. obvia ) and one was not found ( A. arbustorum ), 71 terrestrial gastropod species are new records for the region.

Second records of Bythiospeum iltchokolevi Georgiev & Glöer, 2015 , Discus rotundatus (Müller, 1774) , and Oxyloma dunkeri (L. Pfeiffer, 1865) in Bulgaria were reported. New distributional data about some invasive aquatic molluscs as Anodonta woodiana , Corbicula fluminea , and Ferissia fragilis was provided.

According Cuttelod et al. (2011) all clams from the region have conservation status: 3 species are in category NA – not applicable, 6 species – least concern and 2 ( U. crassus and U. tumidus ) are VU – vulnerable. From the fresh- water snails 24 species are in category LC – least concern, and one in EN – endangered ( T. transversalis ). One fresh water snails is Bulgarian endemic species ( B. iltchokolevi ). From the terrestrial gastropods 29 species are in category LC – least concern, 2 species are in NT – near threatened, and one ( P. seductilis ) is VU – vulnerable. Eight terrestrial gastropods are Balkan Peninsula endemics.

Two more species H. lucorum and H. pomatia are objects of the Bulgarian conservation legislation, as they are included in Section III (Regulated use of plant and animal species), Art. 41 (1), Annex 4 of “Biodiversity Act”.