Bythinella gregoi n. sp.

(Figs 6-9, Fig. 1)

Holotype: 2.7 mm height, 1.4 mm width, NHMH 99693.

Paratypes: 15 sp. NHMH 99694, 4 sp. coll. Glöer, 3 sp. coll. Grego.

Type locality: Romania, Salaj county, 3, 7 km SE of Vălişoara (Dióspatak), below the lowest pond, spring, right side of the brook. N47.356° E23.428°; 15.07.2015 Erőss et Kenéz leg.

Etymology: The species is dedicated to the junior author’s friend and colleague Jozef Grego, Malacologist of Horná Mičiná, Slovakia in honor to his engagement in Hydrobiidae studies.

Description: The horn-colored shell has 4.5 whorls which are slightly convex with a deep suture. The shell is elongated cylindrical-ovate. The aperture is ovate and slightly angled at the top. The peristome is sharp. The umbilicus is slit-like to closed. Aperture height to shell height: 0.4, shell height to shell width 1.6-1.9, height of body whorl to height of spire 1.9-2.1, shell height 2.2-2.6 mm, width 1.3-1.4 mm.

Male copulatory organ: unknown.

Differentiating features: The shells are smaller than the other species of this region. In addition the shells differ in the ratio of height of body whorl to spire.

Ecology: The spring has cold water, shaded by some close conifers. There are water pipes for water collection but the outlet brook is open.

Distribution: Only known from type locality.

Remark: We could only find empty shells of this species. Thus this species possibly lives in the underground of this spring.