A Description of a new Valvata (Mollusca: Valvatidae) from Armenia

A new species of Valvata (Tropidina) is described from Armenia. It is similar to Valvata nowshahrensis Glöer & Pešić 2012 from Iran and V. kebapcii Odabaşi, Glöer & Yıldırım 2015 from Turkey, but has a smaller shell with a narrower umbilicus. We provide data on the sampling site, photos of the new species in comparison with related species. Additionally, the taxonomy of Valvata brandti Westerlund, 1897 from Armenia is shortly discussed.


Introduction
From the holarctic family Valvatidae Gray, 1840 two species have been mentioned from Armenia: Valvata (Cincinna) piscinalis (O.F. Müller 1774) (Akramowski 1976, Vinarski & Kantor 2016, Mashkova et al. 2018 and V. (Tropidina) pulchella Studer 1820 (Akramowski 1968(Akramowski , 1976. The name V. pulchella Studer is a little problematic because V. pulchella Studer, 1798 is not identical with V. pulchella Studer, 1820. Kennard & Woodward (1926: 29) attributed both references to Valvata macrostoma Mörch, 1864, but Boeters & Falkner (1998) stated that V. pulchella Studer, 1789 is a junior synonym of V. piscinalis (Müller, 1774) and established the new name V. studeri Boeters & Falkner, 1998 for the taxon described by Studer in 1820. Nevertheless do the most records of V. pulchella actually refer to V. macrostoma, an European-Siberian lowland species with a scattered distribution from Great Britain in the west to Siberia in the east and from southern Sweden in the north to Bulgaria (Odabaşi et al. 2015) in the south. However, V. macrostoma does not occur in Armenia (Zhadin 1952, Vinarski & Kantor 2016, Bank & Neubert 2017) and Akramowski's records refer to a hitherto undescribed species of Valvata (Tropidina). The aim of this paper is to describe this new species Valvata armeniaca n. sp., and to expand the knowledge about the freshwater molluscs of Armenia.

Materials and Methods
The snails were collected by FW fixed in 70% isopropanol. The photographs were made with a digital camera system (Leica R8). The type material is stored in the Zoological Museum of Hamburg (ZMH) and the collection of the second author (FW).

Etymology:
The new species is named after Armenia, the country of its origin.

Description:
The corneous shell has 2.5 circular whorls with a low spire and a blunt apex. The surface has weak growth lines. Within the umbilicus, the penultimate whorl is covered to 75% of its width by the body whorl (measured at the aperture). Shell height 1.2-1.7 mm, diameter 2.2-2.5 mm. The umbilicus is 0.8 mm wide (32-36 % of the shell diameter). The aperture is circular.

Anatomy:
The penis is long and cylindrical, tapered at the distal end, which corresponds to the drawing of Akramowski (1976: 89), and as it is in Valvata nowshahrenis (Glöer & Pešić 2012, fig. 14) and all other Valvata spp. The male and female sex tract in Valvata spp. is very simple and not suitable for species identification. Differentiating features: Valvata armeniaca n. sp. has a smaller shell with a narrower umbilicus than V. nowsharensis and V. kebapcii Odabaşi, Glöer & Yıldırım, 2015. The exact differences between the species are displayed in Table 1.
Distribution: In addition to the type locality, V. armeniaca n. sp, is also known from Jrahovit, from where Akramowski (1976: pl . 1 fig. 3) figured it as V. pulchella. Both localities are in the drainage area of river Aras making it likely that the new species is also distributed in other wetlands of the Aras drainage system. Records of V. pulchella from the lower part of river Aras in Azerbaijan (Aliyev 2014) could refer to the new species. Habitat (Fig. 3): Living specimens were collected in dense submerged vegetation. At the type locality river Kasakh has a relatively weak current and carries less water than further upstream due to water withdrawal for the intense agriculture of the surrounding areas. At Jrahovit it was found among partly submersed Nasturtium at a small open spot in the dense reed vegetation of a ditch. Akramowski (1976) mentions the species from weakly flowing water of summer-dry marshes around springs and in drainage canals. Associated species: Hippeuthis complanatus (Linnaeus, 1758); Lymnaea spec.; Pisidium spec., Shadinia terpoghassiani (Zhadin, 1952) and an unidentified bithyniid.
Discussion: When describing a new Valvata from Armenia it is necessary to discuss the identity of Valvata brandti Westerlund, 1897, the only Valvata species described from that country before. Although we had no access to the type material we feel entitled to correct some inaccuracies in Haszprunar (2014) concerning the origin and the synonymy of the taxon. The original description of V. brandti is based on two lots. One was collected by A. Brandt in Lake Sevan, while the other was found by L. Młokosiewicz near Lagodekhi in Georgia. Between both localities is a distance of more than 150 km. The Lagodekhi record belongs to Caspicyclotus sieversi, the only Caucasian member of the terrestrial prosobranch family Cyclophoridae and indeed very similar to some Valvata species. The other lot, however, seems to belong to Valvata piscinalis, which is known to occur in Lake Sevan (e.g. Mashkova et al. 2018). The name V. brandti could therefore also be a synonym of V. piscinalis according to a later definition of the taxon by a lectotype. In any case, V. brandti is very different from the species described above.