New taxa of freshwater snails from Macedonia ( Gastropoda : Hydrobiidae , Amnicolidae )

A new representative of a new genus and a new Bythinella species have been found in Macedonia, Sumia macedonica n. gen. n. sp. and Bythinella golemoensis n. sp. The shells of the holotypes and paratypes as well as the penis morphology are depicted.


Introduction
From R. Macedonia only two Bythinella species are known so far: Bythinella drimica drimica Radoman, 1976 and Bythinella melovskii Glöer & Slavevska-Stamenković, 2015, both of which occur at the border to Albania, north of Lake Ohrid (Radoman 1983, Glöer & Slavevska-Stamenković 2015).In the other mountainous surrounding countries many more Bythinella species are known: from Croatia to Montenegro and Serbia 12 Bythinella spp.(Glöer & Pešić 2014), from Montenegro three species (Glöer & Pešić 2010), and from Bulgaria 21 species (Glöer & Pešić 2006, Georgiev & Glöer 2013, 2014, Georgiev & Hubenov 2013).This indicates that the freshwater molluscs in the abundant springs of R. Macedonia are not well investigated.Only the ancient Lakes Ohrid and Prespa and some springs in their vicinity as Sveti Naum with many endemic species have been in the focus of many malacologists.From springs in the Ohrid basin some endemic species are known, for example Pyrgohydrobia jablanicensis Radoman, 1955 which has been described from the (nowadays not accessible) cave just beneath the sampling site of Sumia macedonica n. gen.n. sp., which was not found by Radoman.

Material and Methods
The living animals were collected by hand from stones in the artificial lake in front of the Šum spring and from stones in the springs near Golemo Ezero.Photos of the habitat and living animals were taken by A.C. Mrkvicka and I. Drozdowski.The measurements were carried out by means of ZEISS stereo microscope and an eye-piece micrometer.The photographs were taken with a digital camera system (LEICA).Morphological

Research Article
terms used for descriptions are in accordance with Hershler & Ponder (1998).The material is stored in the National History Museum Vienna (NHMW).Description.The shell is ovate-conic with 4-5 whorls.The whorls are slightly convex, the aperture is ovate with a simple outer lip.The penis is long and slender.

Differentiating features:
The penis of Grossuana spp.resemble that of Sumia but the shells are much smaller and the whorls are less convex.Pyrgohydrobia Radoman, 1955 has a long triangular penis with a broad basis, very different from Sumia.At least no species could be found in the Balkans with a similar morphology of the penis and the shell.

Description
Shell.The light brown shell is ovate-conic with 4-5 whorls and a deep suture.The surface is rough with fine growth lines.The whorls are slightly convex, the aperture is ovate with a simple outer lip, the periostome is sharp, thickened at the columella.The operculum is reddish-brown, umbilicus is closed.Shell height 2.9-3.1 mm, width 1.8 mm.
Animal.The mantle is grayish black, the snout is white, the black eyes are surrounded by white areas.The tentacles are cylindrical, long and rounded at the tip.Morphology of the penis.The penis is long and slender without any outgrowth, usually bent twice (fig.6), not pigmented and sharply tapered at the distal end.

Habitat and ecology:
The powerful cold spring emerges from a cave, it is fed by carstic waters from Jablanica mountains.Due to the drinkwater catchment supplying the city of Struga, the cave is not accessible.In front of the cave an artificial lake (1-3 m deep, size about 150x50 meters) with concrete walls and stony ground contains clear and cold water from the springs.Growth of aquatic macrophytes (Ranunculus trichophyllos, Berula erecta, Myriophyllum spicatum) is abundant, Sumia macedonica was observed on and under stones in the lake and in the watercourse from the cave/water catchment to the lake.
Distribution: Only known from type locality.
Soft body.Mantel black with a white border, tentacles long and thin.
Morphology of the penis.Penis as long as the penial appendix, flagellum relative short and regularly thick.Differentiating features: From Bythinella drimica drimica, it differs in shell morphometry: shell height 1. 97-2.31 in B. d. drimica vs. 2.7-2.9 mm in B. golemoensis n. sp., and shell width 1.13-1.30 in B. d. drimica vs. 1.6-1.7 mm in B. golemoensis n. sp. (measurements of B. d. drimica after Radoman 1983).The umbilicus in B. d. drimica is slit-like, closed in B. golemoensis n. sp.From B. melovskii it differs in aperture height to shell height ratio which is in B. melovskii 0.44-0.47 and 0.39-0.44 in B. golemoensis n. sp.In addition the penis is longer than in B. melovskii while the tubular gland is shorter.

Habitat and ecology:
The cold springs where B. golemoensis lives are situated at the foot of a natural dam and fed by the lake, which is situated above the dam.The water emerges from the base of the dam at about 120 m length.Vegetation is like in alpine springs with abundant growth of mosses on and between stones.Living B. golemoensis were found on and under stones.Water temperature was about 8°C in July.In Bulgaria Bythinella spp.could not be found above 2000 m alt.