Research Article ISSN 2336-9744 (online) | ISSN 2337-0173 (print) The journal is available on line at www.ecol-mne.com
http://zoobank.org/urn:lsid:zoobank.org:pub:724A7D13-BF8C-4643-91BD-44B9BB2ADE45
Two new species of the genus Bythinella Moquin-Tandon, 1856 (Mollusca: Gastropoda: Hydrobiidae) from the Western Balkan Peninsula)
PETER GLÖER 1 and VLADIMIR PEŠI Ć2
1Biodiversity Research Laboratory, Schulstr. 3, D-25491 Hetlingen, Germany. E-mail: [email protected] .3Department of Biology, University of Montenegro, Cetinjski put b.b, 81000 Podgorica, Montenegro. E-mail: [email protected].
Received 12 December 2014 │ Accepted 19 December 2014 │ Published online 20 December 2014.
Abstract Two new species of the genus Bythinella Moquin-Tandon, 1856 , i.e. B. marici n. sp. from Bosnia and Hercegovina, and B. istoka n. sp. from Kosovo were described. The holotypes of both species as well as the penis morphology are depicted. In addition a list and distribution map of the Bythinella spp. occuring in the Western Balkan Peninsula is provided.
Key words : new descriptions, gastropoda, Bosnia & Hercegovina, Kosovo.
Introduction
The genus Bythinella Moquin-Tandon, 1856 is distributed from west Europe (the Iberian Peninsula), to west Asia. The genus have at least two centers of the species richness, France with 42 known species (Bichain et al . 2007), and Bulgaria with 22 species (Georgiev and Glöer 2014). Species of the genus Bythinella occur predominantly in springs and spring-fed brooks, where they can form large populations. Passive dispersal is difficult due to its habitat preferences, thus most of the species are locally endemic, especially in mountainous regions (Glöer and Georgiev 2011). Phylogeographic studies show that the Balkan Peninsula (along with two other peninsulas of Southern Europe—Iberian and Apennine) was a refuge of genetic diversity during the Pleistocene (Hewitt 1999). The recent phylogenentical analysis by Falniowski et al . (2012) on the Bythinella populations in the Balkans showed the presence of two large clades, although they were weakly supported. One of them comprised the Romanian and populations from the Western Balkan Peninsula (Montenegro, and one population from Western Serbia), the other one (less genetically diversified) consisted of populations from the Eastern Balkan Peninsula (Bulgarian and Greek populations, and one population from Eastern Serbia). According to Bank (2011) ten species of the genus Bythinella occur in region of the Western Balkan (Albania and the former Yugoslavia, except Slovenia) which is under discussion here. Glöer (2008) added two Bythinella species from Serbia, B. nonveilleri Glöer, 2008 (East Serbia) and B. pesterica Glöer, 2008 (West Serbia). According to Falniowski et al . (2012) phylogeographic analysis, the latter species belong to the ‘Western Balkan Clade’, while B. nonvelierri belong to clade which includes populations from Greece and Bulgaria. These two large clades in the inferred phylogeny are well-defined geographically (Falniowski
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NEW BYTHINELLA FROM BALKAN PENINSULA et al . 2012), and we can speculate that the third Serbian Bythinella species, B. serborientalis Radoman, 1976, from East Serbia, belong to the latter clade. The karst areas in the Dinaric region of the Western Balkan Peninsula are a hotspot of freshwater biodiversity. Most of the Bythinella species listed for the Western Balkan Peninsula are local or regional endemic, and only B. opaca (M. von Gallenstein, 1848) is widely distributed. However, it is very likely that B. opaca represents a species aggregate with many populations over a wide range of countries (Feher 2010). The aim of this paper is to give a review of the Bythinella spp. of the Western Balkan Peninsula, and to describe the new species from Bosnia and Hercegovina and Kosovo.
Figure 1 . Distribution of the species of the genus Bythinella in the Western Balkan Peninsula. Sampling sites of the new Bythinella species are marked by red dots. The distribution map is made considering the papers by Radoman (1976, 1983), Glöer (2008), Fehér & Er őss (2009), and Glöer & Peši ć (2010).
Material and Methods
The snails were collected with a sieve or by hand, sorted on the spot from living material and preserved in 75% ethanol. The dissections and measurements of the genital organs and the shells were carried out using a stereo microscope (Zeiss); the photographs were taken with a digital camera system (Leica). The following characteristics are used in identification of Bythinella spp.: (i) the shell: shape, height, ratio of aperture height of shell height, umbilicus, aperture, and (ii) the male copulatory organ: ratio of the length of the penis to the penial appendix, flagellum length, width of the proximal and distal part of the
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flagellum. The shape of flagellum has been often overlooked, but this seems to be an important feature to distinguish Bythinella spp (Glöer and Georgiev 2011). The male copulatory organ was studied on at least three specimens from every sample to find the constant features of this organ. The studied material is stored in the Zoological Museum Hamburg (ZMH) and the private collection of the senior author. . Table 1 . Species of the genus Bythinella in the Western Balkan Peninsula.
Taxon Distribution Taxon Distribution Bythinella dispersa Radoman, 1976 Montenegro, Bythinella nonveilleri Glöer, 2008 Serbia Serbia Bythinella drimica drimica Macedonia, Bythinella opaca (M. von Croatia, Bosnia & Radoman, 1976 Albania Gallenstein, 1848) Hercegovina, (= B. schmidti (Küster, 1852)) Serbia Bythinella drimica alba Radoman, Kosovo Bythinella pesterica Glöer, 2008 Serbia 1976 Bythinella luteola Radoman, 1976 Montenegro Bythinella samecana Clessin, 1911 Bosnia and Hercegovina Bythinella kapelana Radoman, Croatia Bythinella serborientalis Radoman, Serbia 1976 1976 Bythinella magna Radoman, 1976 Croatia Bythinella taraensis Glöer & Peši ć, Montenegro 2010
Figure 2-6. Photos of some selected species of the genus Bythinella from the Western Balkan Peninsula. 2 B. opaca (M. von Gallenstein, 1848) (topotype). 3 B. luteola Radoman, 1976. 4 B. dispersa Radoman, 1976. 5 B. taraensis Glöer & Peši ć, 2010. 6 B. pesterica Glöer, 2008 .
Systematics
Genus Bythinella Moquin-Tandona, 1856
Bythinella marici n. sp. (Figs. 7-10)
Type series. Holotype (ZMH 79884): Shell height 3.5 mm, shell width 2.1 mm; Bosnia and Hercegovina, Grahovsko Polje, Bosansko Grahovo town, River Korana near village Luka, leg. Mari ć. Paratypes (ZMH 79885): 6 ex.; 6 ex. coll. Glöer, same data and locality as holotype.
Locus typicus. Bosnia and Hercegovina, Grahovsko Polje, Bosansko Grahovo town, River Korana near village Luka, 44° 9'41.07"N, 16°23'14.82"E.
Etymology. Named after Prof dr Drago Mari ć (Department of Biology, Podgorica), collector of the new species, in appreciation of his studies on Montenegrian biodiversity.
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Figures 7-10 . Bythinella marici n. sp.: 7 shell (holotype), 8 shell (paratype), 9 penis in situ, 10 penis with flagellum.
Description Shell. The large shell is whitish and cylindrical. The 4.5 whorls are convex with a very deep suture. The surface is silky and finely striated. The apex is obtuse, the umbilicus is slit-like. The aperture is oval. Shell height 3.3-3.5 mm, width 2.0-2.1 mm mm, height aperture/shell ratio 0.43.
Soft body. The mantle is black with a greyish boarder, the head is whitish.The penis is shorter than the penial appendix. The flagellum is long, thin at the proximal end and broad at the distal end.
Differentiating features . It is one of the largest species of this genus in the Balkan Peninsula. Only two Bythinella species from the Gacko polje, a karstic field (= polje) in Croatia, are larger: B. magna Radoman 1976, with a shell height of 4.55-5.21 (Radoman 1983: 209) and B. kapelana Radoman 1976 with a shell height of 4.33-4.70. In addition to the dimensions, these species differ in the shape of aperture: in B. magna the aperture is a relatively low (height aperture/shell ratio 0.38, data taken from Radoman 1983) while in B. kapelana aperture is nearly elliptical.
Distribution . Bosnia and Hercegovina; known only from the type locality (Fig. 14).
Bythinella istoka n. sp. (Figs. 11-13)
Type series . Holotype (ZMH 79886): Shell height 2.8 mm, shell width 1.6 mm; Kosovo, Istok town, spring Vrelo, leg. Berlajolli. Paratypes (ZMH 79887): 10 ex.; 17 ex. coll. Glöer, same data and locality as holotype.
Locus typicus . Kosovo, Istok town, spring Vrelo, 42°46'29.6"N, 20°23'58.1"E.
Etymology . Named after the town (Istok) where the species was found.
Description Shell : Shell whitish, cylindrical, its 4.5 whorls slightly convex, with a deep suture. The first two whorls small in height, the other whorls are fast growing. Surface silky and finely striated. Apex obtuse, umbilicus closed. Aperture oval, its top angled, periostome thickened at the columella. Shell height 2.7-2.8 mm, width 1.5–1.6 mm, height aperture/shell ratio 0.46.
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Figures 11-13 . Bythinella istoka n. sp.: 11 shell (holotype), 12 penis in situ, 13 penis and flagellum.
Soft body. The mantle is black, the head is greyish with a dark stripe from eye to eye. Penis shorter than penial appendix. The flagellum is long, attenuated proximally.
Differentiating features . Bythinella istoka n. sp. can be distinguished from the other species of this genus from the Western Balkan by the first two whorls, which are small in height. The similar shape of the first two whorls is found in B. taraensis , but the shell of the latter species is broader (1.8-1.9 mm vs . 1.5-1.6 mm in Bythinella istoka n. sp.) by nearly the same shell’s height. In addition B. taraensis differs by the flagellum which is longer, and thin along the entire length.
Distribution . Kosovo; known only from the type locality (Fig. 15).
Figure 14 . Photo of the type locality (river Korana near village Luka, Grahovsko Polje, Bosnia and Hercegovina) of Bythinella marici n. sp. Photo. D. Mari ć.
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Figure 15 . Photo of the type locality (spring Vrelo near town Istok, Kosovo) of Bythinella istoka n. sp. Photo. V. Berlajolli.
Acknowledgements We like to express our thanks to Willy De Mattia (Trieste) and Dilian Georgiev (Plovdiv) for helpful comments to the manuscript. Furthermore, we are thankful to Dr Drago Mari ć (Podgorica) and Violeta Berlajolli (Pejë) for the collecting material examined in this study.
References
Bank, R.A. (2011) Checklist of the land and freshwater Gastropoda of Albania and former Yugoslavia. In: Fauna Europaea Project,
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Papers dedicated to the memory of Guido Nonveiller . Institute for Nature Conservation of Serbia, Monograph, 22, 349–356. Glöer, P. & Georgiev, D. (2011) Bulgaria, a hot spot of biodiversity (Gastropoda: Rissooidea)? Journal of Conchology , 40 (5), 1–16. Glöer, P. & Peši ć, V. (2010) The freshwater snails of the genus Bythinella Moquin-Tandon (Gastropoda; Rissooidea: Hydrobiidae) from Montenegro. Archives of Biological Sciences , 62, 441–447. Hewitt, G. M. (1999) Post-glacial re-colonization of European biota. Biological Journal of the Linnean Society , 68, 87–112. Fehér, Z. (2010) Bythinella opaca . The IUCN Red List of Threatened Species. Version 2014.3.
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