Arganiella tabanensis n. sp. from Montenegro (Mollusca: Gastropoda: Hydrobiidae)

The first Balcan representative of the Central-Western Mediterranean genus Arganiella Giusti & Pezzoli, 1980 is here described. It has been collected in the Taban spring in Montenegro. Hitherto only two species of this genus are known: A. pescei Giusti & Pezzoli, 1980 from Italy and A. wolfi (Boeters & Glöer, 2007) from Spain.

of the bursa; the receptaculum is also globular but somewhat smaller than the bursa; a proximal receptaculum (PRS = RS2) could not be found.  , V-like bend of intestine in the roof of the mantle cavity seen through shell wall; B (female), sections of the intestine filled with faecal pellets and bursa copulatrix seen through shell wall; C (same female as for Fig. 3B), proximal part of the mantle removed and body lumen opened to such an extend that the V-like bend of the intestine in the roof of the mantle cavity is separated from the proximal and the distal section of the intestine to expose bursa copulatrix and receptaculum seminis. ag = albumen gland, bc = bursa copulatrix, fp = faecal pellet, in = intestine, rs = receptaculum seminis, op = operculum, ws = wall of stomach.
Habitat and distribution. Only known from type locality (Fig. 4). The new species was collected in a small rheocrene spring in deciduous forests dominated by common beech (Fagus sylvatica L.). The spring water and sediment had a smell of hydrogen sulphide.   differs by a gill with 17-18 instead of 11 lamellae, further, a coiled instead of U-like bend intestine on the pallial wall and, finally, a greater difference in size of bursa and receptaculum, that is a larger bursa and a smaller receptaculum compared to the new species. The far remote Arganiella wolfi (Boeters & Glöer, 2007) can be differentiated by a penis with a black pigmented core and an oblong and not globular bursa.
In Hauffenia tellinii, the type species, the operculum is provided with a peg and the rectum strongly coiled.
In the type species of Heraultia, H. exilis (Paladilhe, 1867), the pedunculus enters the bursa proximally and not distally.
In males of Kerkia kusceri (Bole, 1961), the type species, the penis carries a lobe.
Sardohoratia sulcata Manganelli, Bodon, Cianfanelli, Talenti & Giusti, 1998, the type species, differs by the presence of a second receptaculum (RS2 = PRS). Arganiella has been reported from Spain and Italy, inter alia from the Tyrrhenian side of Apennines and Abruzzo vis-à-vis the Dalmatian coast ( Fig. 1). This is in analogy to another genus of the Hydrobiidae, i.e. Islamia Radoman, 1973 with species with valvatoid shells. Species of Islamia are known from the mainland of Italy and from the Balkans as well.
The following list compiles characters of ctenidium, intestine, males and females of species of genera with valvatoid shells (alphabetical order) followed by a summarising table. List and table aim at a deepened characterisation of Arganiella with A. tabanenensis n. sp.
Arganiella . A species of this genus, known from Italy with its type species only (Bodon et al. 2001: 173 fig. 186), has recently been reported also from Spain . These species show a well-developed ctenidium (Giusti and Pezzoli 1981: 210-211  Bracenica Radoman, 1973. In the type species of the Balkanese genus Bracenica (Bodon et al. 2001: 173 fig. 186), that is B. spiridoni Radoman, 1973, the operculum shows an outgrowth on its inner side which twists and penetrates into the foot of the animals (Radoman 1983: 66). The penis of males shows a lobe (Radoman 1983 : 67 fig. 29). As regards the female genitalia with bursa, distal and proximal receptaculum, the distal receptaculum (RS1 or DSR) is embedded by the hollow formed by the bursa and its pedunculus (Radoman 1983: 67 fig. 29), it does not lean over the wall of the bursa as in the monotype of the new genus. The ctenidium and intestine of B. spiridoni has not yet been examined. Arconada & Ramos, 2001. Reference can be made to the foregoing comments on Boetersiella. The only species of Chondrobasis and which is only known from Spain, can be distinguished from the two known species of Boetersiella simply by a penis of their males which is not simple but provided with a papilla, and by a proximal receptaculum (RS2 or PRS) of their females which does not lean over the bursa (Arconada & Ramos 2001: 974 fig. 16D).

Chondrobasis
Dabriana Radoman, 1974. The monotype of this genus, D. bosniaca Radoman, 1974, differs from species of Arganiella by a shell with spiral striations, a caudal tentacle, a missing gill, an presumably U-like bent rectum (Radoman 1983: 169 fig. 102A) and in females a small bursa and a receptaculum much larger than the bursa. The penis is simple.
Daphniola Radoman, 1973. The shell of its type species, D. graeca Radoman, 1973, is globular and not planispiral (Radoman 1983: pl. 5 fig. 87). The penis of males carries a lobe (Radoman 1983 : 84 fig. 45). The female genitalia of the type species comprise a bursa and 2 receptacula. The distal receptculum (RS1 or DSR) is surrounded but not embedded by the hollow formed by the bursa and its pedunculus (Radoman 1983: 84 fig. 45) and does not lean over the wall of the bursa. Ctenidium and intestine of D. graeca has not yet been examined. Daphniola has only been reported from the Balkans yet (Bodon et al. 2001: 173 fig. 186).
Hauffenia Pollonera, 1898. Species of this genus have been described from the Balkans up to Austria and northeast Italy. The operculum of e.g. H. tellinii (Pollonera, 1898), the type species, is provided with a well developed peg. A ctenidium is present. The final section of the intestine is strongly coiled (double sack-like folded) (Bodon et al. 2001: 123 figs 77-79). Bursa and proximal reptaculum (RS2 = PRS) are present, but a distal receptaculum (RS1 or DRS) is missing (Bodon et al. 2001: 123 figs 78-80).