Grossuana Radoman , 1973 from Macedonia ( Greece ) ( Gastropoda : Truncatelloidea ) with the description of three new species

Four samples of hydrobiids from Macedonia (N-Greece) have been studied, two of which could be identified as Grossuana angeltsekovi, a widely distributed species in Bulgaria and N-Greece. Three species are described as new for science by morphology of the shell and penis. A distribution map, photos of the shells and the penis are presented. The material has been collected by Robert Reuselaars and Kyriakos Papavasileiou during a field trip in September 2017.


Introduction
The genus Grossuana Radoman, 1973 is widely distributed in the Eastern Balkan Peninsula (Radoman 1983, Falniowski et al. 2016, Georgiev et al. 2015) and inhabits predominantly springs.Radoman (1983) reported representatives of Grossuana from Romania, Serbia, Bulgaria and Greece but they do not occur in Asian Turkey (Yıldırım 1999).The first record of Grossuana from FYROM has been reported by Boeters et al. (2017) as G. maceradica.The highest species diversity can be found in Bulgaria with 8 nominal taxa and 6 species in Central Greece (Falniowski et al. 2015).
The first paper of the mollusk fauna of Macedonia (N-Greece) has been published by Wagner (1927) but he did not list hydrobiid snails of this region.The freshwater mollusk fauna of Macedonia (N-Greece) is not well investigated yet.

Material and Methods
The freshwater snails were collected in September of 2017 on 4 sampling sites (Table 1) using a sieve and pincer.The samples were preserved in 90% ethanol.The dissections and measurements of the genital organs and the shells were carried out using a Zeiss stereo microscope with an eyepiece-micrometer; the photographs were made with a Leica R8 camera system with a digital adapter.
The holotypes and paratypes are stored in RMNH (Rijksmuseum van Natuurlijke Historie, Leiden, The Netherlands) and in the collections of Reuselaars and Glöer.

Results
New samples of hydrobiid snails revealed some Grossuana spp.from Macedonia (N-Greece) of which three species are new for science.All these species are only known from their type localities.
Genus Grossuana Radoman, 1973 Radoman (1983) described the genus Grossuana as follows: "Shell ovoid, rarely somewhat elongated or shortened.With a strongly developed last whorl and an ovoid aperture.Operculum red.… Penis long, with a very prolonged, pointed top and a weak outgrowth on the left side, which is hardly visible in many specimens."That the shape of the penes of distinct species-groups look different in Grossuana spp.has already been depicted by Georgiev et. al. (2015).They all have in common the tapered penis-tip which is much slimmer than the rest of the penis (e.g.Fig. 3.2).
In Distribution: Grossuana angeltsekovi has been found on sampling sites 3 and 4 (see table 1 and figs.[18][19].It is widely distributed in Bulgaria (Georgiev et al. 2015, Falniowski et al. 2015), as well as in the Greek part of the Rhodope Mountains (Georgiev et al. 2013).The sampling sites mentioned above have not been reported before.Locus typicus: well near small church west of Avandas, Prefecture of Evros, Greece.Wet place quit hidden under Platanus trees, there was no stream or real waterflow, water dried up after 4-5 m. 08.09.2017R.E.Reuselaars leg.The specimens were collected from the leaves.

Description:
The yellowish brownish shell is ovate-conical with a prominent body whorl.The 4.5-5 whorls are fast increasing, convex with a clear suture.The aperture is ovate, slightly angled at the top.The periostome is thinkened at the columella.The umbilicus is closed.The operculum is red.
The shell height is 1.5-1.7 mm, shell width 1.2 mm.The mantle is black with a light-grey border.The penis has a small triangular outgrowth at the left side near the basis (Fig. 2.2).The penis-tip is long and tapered.

Description:
The horn-coloured shell is ovate with a prominent body whorl.The 4.5-5 whorls are slightly convex with a weak suture.The aperture is ovate slightly angled at the top with a sharp periostome.The umbilicus is closed.
Shell height 1.7-1.9mm, width 1.2-1.3mm.The mantle is black with a light-grey border.The penis is slim with a tapered penis-tip.At the basis of this tip is a dark spot visible.

Differentiating features:
The shell of Grossuana stenaensis n. sp. is broader than G. slavyanica and the penis-tip is shorter than in G. angeltsekovi and different from the Grossuana spp.described here as new.

Description:
The brownish shell is ovate with 4.5 fast growing whorls which are slightly convex with a weak suture.The periostome is sharp and the umbilicus is closed.The aperture is ovate, the operculum is red.
The shell height is 1.3-1.8mm, width 1.0-1.3mm.The mantle is black with a light-grey border.The penis is nearly regularly broad with a small tapered penis-tip.There is a dark spot at the basis of the penis-tip.

Differentiating features:
The penis is regularly broad with a small and thin tapered penis-tip by which it differs from G. angeltsekovi and G. slavyanica, as well as from the Grossuana spp.described here as new.
Remark: All specimens are coated with a layer of Fe/Mn (Fig. 17).

Table 1 .
The sampling sites.Spring in St. Johns gorge, north of Thiriopetra, Prefecture of Pella, Greece.Concrete construction, specimen on small stones and leaves in spilled water (spring connected to watersupply) 12.09.2017R.E.Reuselaars leg.