SOME NEW FRESHWATER GASTROPODS FROM SOUTHERN EUROPE ( MOLLUSCA : GASTROPODA : TRUNCATELLOIDEA )

A western Balkan representative of the Moitessieriidae collected in a spring is described as Bosnidilhia vreloana n. gen. n. sp. A species of the Hydrobiidae from the Republic of Srpska (Bosnia and Hercegovina) is described as Islamia dmitroviciana n. sp.


INTRODUCTION
Representatives of the Moitessieriidae were previously known from Spain, France, Italy and Greece.Moitessieria simoniana Saint Simon, 1848, M. massoti Bourguignat, 1863 and Sardopaladilhia plagigeyerica Manganelli, Bodon, Cianfanelli, Talenti et Giusti, 1998 were known to occur in Italy, and only Clameia brooki Boeters et Gittenberger, 1990 was recorded from Greece.No moitessieriid was known from the area between Italy and Greece.The Moitessieriidae live in subterranean habitats; their members often occur together with or near other species of the Moitessieriidae, or of the Hydrobiidae, for example of Islamia Radoman, 1973.It seemed promising to look for Moitessieriidae and other subterranean species within the gap between Italy and Greece.
Recent field work in the northwestern Balkans (Republic of Srpska, Bosnia and Hercegovina, Fig. 1) revealed an unknown representative of the Moitessieriidae.It is the first record for this family within the area between Italy and Greece.The new species was found rather close to the locality of a new species of Islamia; the two species occur in springs and their subterranean drainage areas, respectively.
Benthic samples were collected using a Surber sampler, and freshwater snails were sorted in the laboratory with the aid of a stereo microscope.The shells and genitalia were examined under a stereo microscope; photographs were taken with a Leica digital camera system.Preservation and dissection of snails was carried out in accordance with BOETERS (1998BOETERS ( , 1999a)).Whorls were counted according to GITTENBEGER et al. (1970).
The following abbreviations of repositories are used in the text: BOE = BOETERS Collection, ZMH = Zoological Museum, Hamburg.Genus: Bosnidilhia n. gen.
Description: A genus of the Moitessieriidae.The shell is of elongated tapered shape (Fig. 2).Upon leaving the style sac the intestine does not closely surround the sac toward the stomach, but first runs toward the mantle cavity wall before turning back, to touch the distal wall of the stomach and turn straight toward the anus along the prostate, albumen and capsule glands.
The penis is simple, without any lobe.There is no gono-pericardial duct in female; the intestine ends with the anus close behind the mantle skirt, the gonopore lies about a quarter of the body whorl behind it.For other shell and body characters see the species description.
Differentiating characters: Bosnidilhia vreloana n. gen.differs from the eight known genera of the Moitessieriidae in the following characters (Table 1).Contrary to Bosnidilhia n. gen., the shells of Baldufa, Clameia, Corseria, Henrigirardia, Moitessieria, Palacanthilhiopsis, Sorholia and Spiralix have a dense spiral or grid-like sculpture.Paladilhia differs in the pallial tentacle and Palaospeum in the distal receptaculum (RS1), characters which are absent in Bosnidilhia n. gen.In Bosnidilhia n. gen. the receptaculum is not simply positioned in the gap formed by the renal oviduct with the pedunculus of the bursa, but touches  Contrary to these genera, the type species of Clameia and Spiralix show such a loop.The characters are summarised in Table 1.No pigmentation except for the style sac which is proximally surrounded by black pigment grains.The intestine leaving the style sac does not closely surround the sac toward the stomach, but runs towards the mantle cavity wall to turn back and touch the distal wall of the stomach and turn straight toward the anus along the prostate, albumen and capsule glands; no loop in the mantle cavity (Figs 7,(13)(14)(15)(16)(17)(18)(19).Sex ratio: 2XX : 1C (FL4 14b).

Male genitalia:
The simple penis is broad and long without any lobe; its short final section is teat-shaped (Figs 3-4, 8, 11).
Female genitalia: The renal oviduct runs down from the ovary and makes a Z-shaped loop in the neighbourhood of the style sac before reaching the albumen gland without any branching off of a pericardial duct (Fig. 12).The last distal bend of the loop carries a minute receptaculum which touches the bursa.The bursa is cylindrical; its pedunculus enters the renal oviduct distal to the receptaculum.The intestine ends with the anus close behind the mantle skirt; the gonopore lies about a quarter of the body whorl behind it.Male genitalia: The male copulatory organ originates in the mantle cavity under the distal branch of the V-like loop of the final section of the intestine (Fig. 31).It is apically bifid and mitten-shaped (Figs 24,(30)(31), that is on its left side the penis is provided with a large penial lobe.On its ventral side and in front of the bifurcation the copulatory organ carries a lamella which extends somewhat beyond the left side of the penial lobe when seen from above; the penial duct zigzags through the penis towards its tip (Fig. 31).Differentiating characters: At present six species of Islamia from the Balkans are well known and discussed below.Further, some comments are made on four other valvatoid species from the Balkans, of unclear generic affiliation, and also on the Italian I. ruffoi.
(5) I. graeca Radoman, 1973 and (6) I. trichoniana Radoman, 1979 are restricted to Greece and occur in a completely different habitat, i.e. lakes and not springs and their subterranean drainage areas.In both these species the penis and penial lobe are small and short.
(11) Finally, as regards Islamia in the neighbouring western Europe, reference is made to I. ruffoi Bodon et Cianfanelli, 2012.However, whereas in I. ruffoi the male copulatory organ is bifurcated into the penis and its lobe (BODON & CIANFANELLI 2012), in I. dmitroviciana n. sp. the male copulatory organ carries in addition a lamella like in other Balkan species of Islamia.Remarks: We had no opportunity to examine the types of Islamia bosniaca Radoman, 1973.No topotypes could be collected since the territory of the type locality situated in the Federation of Bosnia and Hercegovina, close to the border of the Republic of Srpska, is said to be still mined.

DISCUSSION MOITESSIERIIDAE, HYDROBIIDAE AND BYTHINELLIDAE
B O E T E R S & GITTENBERGER (1990) listed conchological and anatomical differences between Hydrobiidae and Moitessieriidae.However, since these differences have not always been confirmed by other authors, and sometimes even ignored, doubted or perhaps overlooked (BODON & GIUSTI 1989: 30;MANGANELLI et al. 1998: 54, 62, fig. 19) and since the new genus Bosnidilhia n. gen. is assigned to the Moitessieriidae, it seems reasonable to update the list of differentiating characters provided by BOETERS & GITTENBERGER (1990).This updating acknowledges the Bythinellidae as a separate family apart from the Hydrobiidae.We also take into consideration WILKE's et al. (2013: 722) statement that the Moitessieriidae are insufficiently studied and their phylogenetic relationships and taxonomic status require further study.
The discovery of Bosnidilhia n. gen.as a distinct genus has expanded our understanding of the structure of female genitalia of the Moitessieriidae.At least three types of the structure can be distinguished: one without receptaculum (Corseria, Moitessieria, Sorholia and Spiralix), another with the receptaculum branching off the renal oviduct close to the bursa pedunculus (Palaospeum), and a third one with the receptaculum carried by the bursa (Bosnidilhia n. gen., Clameia, Palacanthilhiopsis, Paladilhia and Sardopaladilhia).
At present Paladilhiopsis Pavlovic, 1913 is regarded as a junior synonym of Bythiospeum (cf.HAASE 1995).Furthermore, Iglica A. J. Wagner, 1928 has not yet been properly redefined.I. gratulabunda A. J. Wagner, 1910, the type species of the genus, was described from deposits of the river Mürz in Austria (Steiermark), however it has never been recollected and in all likelihood belongs to Bythiospeum (REISCHÜTZ 1988: 69;compare  ISLAMIA RADOMAN, 1973 Species of Islamia Radoman, 1973 are distributed from Spain to Greece.They inhabit subterranean waters and sometimes also outflows of springs downstream of their emergence, with the exception of I. graeca and I. trichoniana which live in lakes.Since 1973 our knowledge of Islamia has been remarkably expanded as several new species of Islamia have been described, especially from Spain, France and Italy.This improved knowledge has revealed that RADOMAN's approach to distinguishing species of Islamia on the basis of the characters of their male copulatory organs is often quite useful.Nevertheless, RADOMAN's (1983: 124) assumption that the male copulatory organ with the basal lamella, as in I. dmitroviciana n. sp., is characteristic of the genus, is not true, as demonstrated by the example of I. ruffoi.

Table 1 .
Differentiating features of the genera of the Moitessieriidae