Bythinella istoka, Glöer & Pešić, 2014

Glöer, Peter & Pešić, Vladimir, 2014, Two new species of the genusBythinella Moquin-Tandon, 1856 (Mollusca: Gastropoda: Hydrobiidae) from the Western Balkan Peninsula), Ecologica Montenegrina 1 (4), pp. 249-255 : 252-253

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.

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).