Cotyorica nemethi n . gen . n . sp . , a remarkable Tertiary relict of the subfamily Phaedusinae ( Gastropoda : Pulmonata : Clausiliidae ) from northern Turkey

Cotyorica nemethi n. sp., one of the Tertiary relict western members of the geographically disjunct subfamily Phaedusinae, is described from Ordu Province of northern Turkey. It shows similarity to the species of the subterranean genera Graecophaedusa Rähle, 1982 and Nothoserrulina Németh & Szekeres, 1995 having high positioned lamellae inferior and subcolumellaris, but differs from these to an extent that justifies distinct generic status.


Introduction
Climatically well balanced coastal regions of the Mediterranean, Black and Caspian Seas with mild winters harbour a remarkably rich and diverse fauna of the land snail family Clausiliidae.Among its unique endemic elements are a few species that represent Tertiary relicts of the mainly Asiatic Phaedusinae subfamily (Nordsieck 1978).In addition to the favourable climate, the survival of most of these clausiliids was ensured by their subterranean habitats capable of providing frost-free and permanent high humidity environment.Due to the hidden life style of several members in this 'European' group (Nordsieck 1978) of the Phadusinae (also including taxa in the Caucasus and Hyrcanian areas), only recent studies (e.g., Rähle 1982;Neubert 1992;Majoros et al. 1994;Nordsieck 1994;Németh & Szekeres 1995;Gittenberger 2000;Reischütz et al. 2016) gave an idea of their previously underestimated diversity.Helped by novel collecting methods, in less then four decades these research efforts increased the number of described species substantially, from 10 (Nordsieck 1978) to 28.A recently discovered species of the subterranean Phaedusinae, representing a new endemic genus of the Black Sea coast, is a further addition to the diversity of these remarkable clausiliids.

Material and Methods
The sample containing the holotype was taken from the upper 2 cm layer of soil at the bottom of an eastexposed cliff.
Measurements and photographs were taken at the Naturhistorisches Museum (Vienna) with a Nikon DS-F2.5 camera mounted on a Nikon SMZ25 stereomicroscope, using NIS-Elements Microscope Imaging Software with an Extended Depth of Focus (EDF) patch.Line drawing of the aperture was done using a photographic template.

Diagnosis:
The diagnostic features of the new genus are the same as those of the type species.

Etymology:
The new genus is named after the ancient name (Cotyora) of Ordu, a major town near the type locality.

Description:
The colourless shell with slightly bent spire consists of 9 1 / 3 flat whorls.The dense ribs of the surface become stronger, sharper and widely spaced at the neck.The ovoid peristome is projected, at the basis not backward-bent.Its wide, reflexed margin has strong plicae all around, except at the sinulus.The lamella superior is moderately emerged, in front view not more conspicuous than the interlamellar plicae.Inward it is smoothly continuous with the lamella spiralis.Deeper than visible through the aperture the lamella inferior divides in two parallel branches, which descend along the lamella spiralis and terminate marginally as strong plicae above half height of the aperture.The uninterrupted lamella subcolumellaris also ends marginally, separated from the lower branch of the inferior by a strong plica.The plica principalis starts ventrolaterally and, gradually converging toward the suture, reaches close to the aperture.On the lateral side it is accompanied by a short upper and a farther forward reaching, twice longer lower palatal plica.The deep clausilium plate is not visible through the aperture.
Dimensions of the holotype: shell height 11.5 mm, shell width 2.9 mm, aperture height 2.2 mm, aperture width 1.7 mm.

Etymology:
The new species is named after László Németh, the collector of the type specimen and an esteemed friend of the authors, who substantially contributed to the research of the Turkish malacofauna.
Habitat: Cotyorica nemethi n. sp. was recovered as an empty shell from a litter-soil sample collected at a cliff.As its closest relatives Graecophaedusa sperrlei Rähle, 1982 andNothoserrulina subterranea Németh &Szekeres, 1995 were found in narrow underground passages between rocks (Németh & Szekeres 1995;Reischütz et al. 2008), it is assumed that this species may have similar habitat preference.This is also suggested by the highly local occurrence of the new species in a zoogeographically well researched region.The holotype may have been washed out from crevices of the cliff by rain water.

Remarks
Among non-decollated western Phaedusinae C. nemethi n. sp.shows superficial similarity to Serrulina serrulata (Pfeiffer, 1847) that differs markedly by its steeply descending and low ending lamella inferior, a feature shared between members of the genera Serrulina Mousson, 1873, Dobatia Nordsieck, 1973, Sciocochlea Boettger, 1935, and Tsoukatosia Gittenberger, 2000.By contrast, the high positioned lamellae inferior and subcolumellaris of the new species (Fig. 2) resemble those seen in the monotypic genera Graecophaedusa Rähle, 1982 andNothoserrulina Németh &Szekeres, 1995. Nevertheless, C. nemethi n. sp. is well distinguishable from Graecophaedusa sperrlei by the narrow apex and less retracted palatal plicae, from Nothoserrulina subterranea by the spindle-shaped shell and the absence of minor folds between the upper and lower plicae, and from both species by the projected aperture with non-recessed basal rim, and the strongly serrate parietal peristome margin.Considering these differences relative to the morphological coherence of species in the non-monotypic genera (e.g., Serrulina, Sciocochlea, Tsoukatosa), they justify the classification of the new species in a distinct genus.Ample all year round rainfall and the narrow, within 15°C range of monthly average temperatures of the southern and eastern Black Sea coast provide ideal climatic conditions for the survival of Phaedusinae species, which were abundant elements of the European Clausiliidae fauna before the Pleistocene period (Nordsieck 2000;Reischütz et al. 2016).This temperate region is home to four highly endemic species (Fig. 3), all of which live in shallow subterranean habitats (Culver & Pipan 2014) and, in accordance with their relict status, belong to monotypic genera.Nordsieck, 1994 (4); Truncatophaedusa evae Majoros, Németh & Szili-Kovács, 1994 (5).