Bythinella temelkovi n. sp.

(Figs. 2-6)

Holotype: H= 2.5 mm, W= 1.5 mm, AH= 1.2 mm. 05.06.2012 D. Georgiev leg., ZMH 79701.

Paratypes: 10 specimens ZMH 79702, 5 shells coll. D. Georgiev, 11 specimens coll. Glöer.

Locus typicus: Strandzha Mts., spring near river at Nestinarka beach, Bulgaria; 42.1549° N, 27.85583° E; alt. 59 m asl .

Etymology: Named in memory of Dilian Georgiev's colleague Dr Blagovest Temelkov (1956 – 2010) who was specialist of fossil and recent Foraminifera, and lecturer at the University of Plovdiv.

Description

Shell.The horn-coloured shell is nearly cylindrical (Figs. 2, 6). The 4.5 whorls are slightly convex with a deep suture. The surface is silky and finely striated. The apex is very small and obtuse, the umbilicus is closed. The aperture is oval, rounded at the top, and from lateral view straight. Shell height 2.1-2.5 mm, width 1.5-1.7 mm, aperture height to shell height ratio 0.48.

Animal. The head is dark pigmented and eye spots are visible.

Anatomy. The penis is three times shorter than the penial appendix (Figs. 3-5), the tubular gland is long and regularly thick (Figs. 4, 5) with 4 half loops.

Differentiating features: Bythinella temelkovi n. sp. belongs to the small Bythinella species of Bulgaria which are smaller than 2.6 mm ( B. markovi Glöer & Georgiev, 2009, B. valkanovi Glöer & Georgiev, 2011, B. gloeeri Georgiev, 2009, and B. slavayae Glöer & Georgiev, 2011). From B. markovi, the new species differs by the closed umbilicus (slit-like in B. markovi) and the long tubular gland (short in B. markovi). B. valkanovi is much slimmer in shell shape than B. temelkovi n. sp. (1.1-1.4 mm in B. valkanovi vs. 1.5-1.7 mm in B. temelkovi). The tubular gland in B. gloeeri and B. slavayae is not regularly thick as it is in B. temelkovi n. sp.

Habitat and ecology: The new species was found in shallow spring among broad leaf bush and tree vegetation, at the bank of a small stream.

Distribution: Known only from the type locality, possibly a local endemic species.