NORTH-WESTERN JOURNAL OF ZOOLOGY 9 (1): 103-112 ©NwjZ, Oradea, Romania, 2013 Article No.: 131301 http://biozoojournals.3x.ro/nwjz/index.html Identification key of the Rissooidea (Mollusca: Gastropoda) from Bulgaria with a description of six new species and one new genus Dilian GEORGIEV1 and Peter GLÖER2 1. Paisii Hilendarski University of Plovdiv, Faculty of Biology, Department of Ecology and Nature Conservation, 24 Tsar Assen Str., 4000 Plovdiv, Bulgaria, E-mail: [email protected] 2. Biodiversity Research Laboratory, Schulstrasse 3, D-25491 Hetlingen, Germany, E-mail: [email protected] * Corresponding authors, D. Georgiev, E-mail: [email protected] Received: 06. January 2012 / Accepted: 15. November 2012 / Available online: 04. January 2013 / Printed: June 2013 Abstract. New investigations of freshwater habitats in mountainous regions and caves revealed six new species of the Rissooidea in Bulgaria. The new species are described here and photos of the holotypes are provided. In addition we added photos of the type localities. An identification key of the genera of the Rissooidea of Bulgaria gives an overview of the diversity of this group. The following species are described as new: Strandzhia bythinellopenia sp. n., gen. n., Grossuana slavyanica n. sp., G. derventica n. sp., Radomaniola strandzhica n. sp., Bythiospeum devetakium n. sp., Bythinella rilaensis n. sp. Key words: Bulgaria, Rissooidea, new descriptions. Introduction 2009, 2011, Georgiev and Glöer 2011, Georgiev and Stoy- cheva, 2011, Georgiev 2009, 2011a, 2011b, 2011c, in press) When Angelov (2000) summarized the freshwater and also a few summary works considering this group of aquatic snails on larger areas (Radoman 1983, Hershler molluscs of Bulgaria he listed 16 species of the Ris- and Ponder 1984, Kabat and Hershler 1993, Glöer 2002, sooidea. By the investigations of mountainous re- Arconada and Ramos 2003). gions and caves, carried out by the senior author, The opinion of Radoman (1983) that most of the spe- now up to 58 species of the Rissooidea are known. cies of Rissooidea differ by their penis morphology was Because the number of species of a checklist de- accepted for this paper. The female genitalia were not in- pends not only on the actual diversity, but also on vestigated. the thoroughness of the investigation as well as on IUCN criteria (2001) in evaluating the conservational status of the species were used. the taxonomical expertise, the species diversity Abbreviations used: H – shell height, W – shell could have been occasioned by the great number width, AH – aperture height. of samples that could be studied by us. The type material was deposited in the Zoological This paper is intended (i) to expand the Museum of Hamburg (ZMH, Germany). knowledge of the molluscan biodiversity of Bul- garia, and (ii) to describe the new species. Taxonomic descriptions Material and Methods Family Hydrobiidae Troschel, 1857 The living snails were collected by hand and preserved in Genus: Strandzhia gen.n. 75% ethanol. The shells were collected by sieving by 1x1 Etymology: Strandzhia because it was found in the and 2x2 mm mesh width sieves. The material from the Strandza Mts. smaller meshed sieve was dried in the laboratory. Later it Description: The conical shell is horn colored was put into water again and the floating shells were col- and consists of 3.5-4 whorls that are slightly lected by a strainer and small brush. The dissections and measurements of the shells were rounded with a weak suture. The aperture is carried out by means of stereo microscope and an eye- ovoid and slightly angled at the top, with a sharp piece micrometer considering the criteria of Radoman periostome that is thickened at the columella. The (1983), and Hershler & Ponder (1984). The photographs penis is regularly broad, smoothly tapering dis- were made with a camera system with a digital adapter. tally and has an appendix shorter than the penis The identification key of the genera of the Bulgarian with a sucker-like apical part (similar to that char- Rissooidea was made with a critical overview on all pub- acteristic of the genus Bythinella Moquin-Tandon, lished papers for Bulgaria considering new descriptions of taxa or summary works (Wagner 1927, Angelov 1959, 1856). The penial appendix in some specimens 1965, 1967, 1972, 1976, 2000, Pintér 1968, Radoman 1983, could bear a small lobe as a brunch of its base. A Hubenov 2005, Glöer and Pešić 2006, Glöer and Georgiev flagellum is missing. 104 D. Georgiev & P. Glöer Differentiating features: The lack of a flagel- ity (Fig. 13). lum discern the new genus from the genera Bythi- Ecology: The species was found on stones at nella, and the newly described Agrafia, Szarowska the bottom of a small stream situated on a & Falniowski, 2011 (Szarowska & Falniowski, meadow on calcareous terrain, it lives together 2011) from Greece. The new genus differs from the with Bythinella margritae Glöer & Georgiev, 2011. rest of the Rissooidea by the presence of a penial Conservation status: As the spring waters of appendix, similar to that of Bythinella. the type locality were already captured for drink- Type species: Strandzhia bythinellopenia sp.n., ing needs, we consider the species as Endangered gen.n. (EN), vulnerable of any further negative anthro- pogenic influence on it. Strandzhia bythinellopenia sp.n., gen.n. Material: 26.09.2009, 29 ex. from the type locality Genus Grossuana Radoman, 1983 (4 males dissected), D. Georgiev leg. Holotype: height 1.8 mm, width 1.4 mm. ZMH Grossuana slavyanica sp.n. 79333 Material: 10.05.2010, 38 ex. from the type locality Paratypes: 10 ex. in ethanol from type locality. (3 males dissected), D. Georgiev leg. ZMH 79334, 18 excoll. Glöer, 10 excoll Georgiev. Holotype: height 2.2 mm, width 1.5 mm. ZMH Locus typicus: Stream below water source 79335. near Mladezhko village, Strandzha Mt, South-East Paratypes: 10 ex. in ethanol from type locality. Bulgaria, N42° 09' 04.6'' E27° 21' 49.3'', 129 m alt. ZMH 79336, 27 excoll. Glöer, 5 excoll. Georgiev. (Fig. 2). Locus typicus: Stream below water source at Differential diagnosis: The penis bears a large Goleshovo village, Slavyanka Mts, South-Western penial appendix but does not have a flagellum. Bulgaria, N41° 25' 52.8'' E23° 35' 19.0'', 762 m alt. Description: Shell: The conical shell is horn (Fig. 4). colored and consists of 3.5-4 whorls that are Differentiating features: The G. slavyanica sp.n. slightly rounded with a weak suture. The surface has the slimmest shell from all known species is glossy with fine growth lines. The apex is very from the genus. small and flattened, the umbilicus is closed. The Description: Shell: The slim, elongate conical aperture is ovoid and slightly angled at the top, shell is horn colored and consists of 4.5 regularly with a sharp periostome that is thickened at the growing whorls that are slightly rounded with a columella (Fig. 1). The operculum is orange- weak suture. The surface is glossy with fine reddish. H = 1.7-1.8 mm, W = 1.4 mm, AH/H = growth lines. The umbilicus is closed. The aper- 0.49. ture is ovoid and slightly angled at the top, with a Animal: The mantle is pigmented in black sharp periostome that is thickened at the colu- with a white border. The head and the bases of the mella (Fig. 3). The operculum is orange-reddish. H snout and the sole are black with white-yellowish = 1.9-2.2 mm, W = 1.3-1.5 mm, AH/H = 0.43-0.45. distal parts. The tentacles are grey with rounded Animal: The mantle is black with a white bor- apical parts. der. The head and tentacle base are grey, the Anatomy: The penis is regularly broad, snout, sole and distal tentacle parts are white. smoothly tapering distally and has an appendix Anatomy: The penis bears a small lobe on its shorter than the penis with a sucker-like apical left side and is pointed at its apical part. A dark part (similar to that characteristic of the genus spot on the penis is present. Bythinella Moquin-Tandon, 1856) (Fig. 1). The Etymology: Named after the Slavyanka Mts penial appendix in some specimens could bear a where the species was found. small lobe as a brunch of its base. A flagellum is Distribution: Known only from the type local- missing. The penis color is yellowish and in some ity (Fig. 13). specimens with very small dark spot at its distal Ecology: The species was found on stones at part. the bottom of a small stream below the water Etymology: Strandzhia because it was found in source at a village, on calcareous terrain. the Strandza Mts., – bythinellopenia because it has a Conservation status: As the spring waters of penis which looks at a first glance similar to the the type locality were already captured for drink- penis of Bythinella. ing needs, we consider the species as Endangered Distribution: Known only from the type local- (EN), vulnerable of any further negative anthro- Identification key of the Rissooidea (Mollusca: Gastropoda) 105 Figure 1. Strandzhia bythinellopenia sp.n., gen.n.: A – shell of the holotype, B, C – penes of two dissected specimens [p – penis, pa – penial appendix, e – eye, t – tentacle]. Figure 2. The type locality of Strandzhia bythinellopenia sp.n., gen.n. near village of Mladezhko, Strandzha Mts. Figure 3. Grossuana slavyanica sp.n.: A – shell of the holotype, B – paratype, C – penis and head [p – penis, e – eye, s – snout]. Figure 4. The type locality of Grossuana slavyanica sp.n. from two views, at village of Goleshovo, Slavyanka Mt. 106 D. Georgiev & P. Glöer pogenic influence on it. meters deep, and the outer stream. Troglophilous species. Grossuana derventica sp.n.