A NEW SPECIES OF PSEUDAMNICOLA PAULUCCI , 1878 FROM KITHIRA ISLAND , GREECE

A new species of Pseudamnicola, P. magdalenae, is described from the spring at Karavas on Kithira Island, Greece. Cytochrome oxidase subunit I (COI) sequences of mtDNA indicate its species distinctness. The shell, female reproductive organs and penis are described. The shell resembles that of the geographically close P. macrostoma (Küster, 1853) from the Greek mainland, but the penis is more triangular and the bursa copulatrix is bigger in P. magdalenae. The simplified anatomy coupled with the wide variation overlapping between the congeneric species is emphasised. key words: molecular distinctness, mtDNA, cytochrome oxidase subunit I (COI), morphological distinctness, shell, penis, female reproductive organs


INTRODUCTION
The genus Pseudamnicola Paulucci, 1878 contains species which are known from the British Isles, the Netherlands and Spain, through France, Italy and the southern Balkans, to Romania (although the latter not confirmed anatomically), Turkey, Cyprus and some other circum-Mediterranean countries (e. g. delicAdo & rAmos 2012, delicAdo et al. 2014), but the systematics of this group is poorly understood (szArowskA et al. 2015).
In Greece, six nominal species of Pseudamnicola were distinguished (schütt 1980(schütt , szArowskA et al. 2006)), four of them inhabiting the islands [P. brachia (Westerlund, 1886), P. pieperi Schütt, 1980, P. chia (Martens, 1889) and P. negropontina (Clessin, 1878)], and two known from continental Greece [(P. macrostoma (Küster, 1853) andP. exilis (Frauenfeld, 1863)].However, all of them were distinguished based solely on shell characters.Recently, rAdeA et al. ( 2016) described two more species from Rhode island (P.ianthe Radea et Parmakelis, 2016 andP. ilione Radea et Parmakelis, 2016), considering molecular data as well.The taxonomy of the genus is poorly understood, the shells are very variable and the anatomy is simple and variable even within a population.Thus the morphology alone may not resolve the systematics of this group and molecular data are required.
In the Truncatelloidea, morphological characters alone are sometimes insufficient even for proper determination of a genus (e.g.szArowskA & FAlniowski 2008, FAlniowski et al. 2012) and all the characters are highly variable within species, the variation ranges overlapping between the species (FAlniowski 1987).For the Greek Pseudamnicola molecular data -mostly mtDNA cytochrome oxidase subunit I (COI) -are already available for several taxa (szArowskA et al. 2006, 2015, szArowskA & FAlniowski 2011, rAdeA et al. 2013, 2016).Molecular data suggest that the number of species of the Greek Pseudamnicola described so far is underestimated -at least 16 lineages of presumably species rank have been found in Greece (szArowskA et al. 2015).One of the most distinct lineages inhabits the spring at Karavas on Kithira Island.

MATERIAL AND METHODS
About fifty specimens of Pseudamnicola were collected from the spring at Karavas, northern part of Kithira Island; 36°20'50.4"N,22°56'57.8"E,66 m a.s.l.In this big spring, in the form of a medium-sized pond, Pseudamnicola co-occurred with Melanopsis.Snails were collected by hand or with a sieve, and fixed with 80% ethanol.The shells and the soft body parts were photographed with a CANON EOS 50D digital camera, under a NIKON SMZ18 microscope with dark field and phase contrast.Five males and five females were dissected; photographs of the soft parts were used for drawing the features of internal anatomy.Character state terminology follows that defined by hershler & Ponder (1998).1. Operculum smooth on its inner and outer surface, yellowish.Soft parts densely pigmented black.Female reproductive organs (Fig. 9) with big, spherical bursa with long duct, one small and bulky receptaculum seminis in the position of rs 1 and long loop of oviduct pigmented black.
Etymology.Named in memory of Dr Magdalena Szarowska, a malacologist, my wife and best friend, who loved Greece.Distribution and habitat.Known from the type locality only.However, considering the relatively small genetic distance (p = 0.02), the population inhabiting the spring at Viaradika, central Kithira Island, may belong to this species.

DISCUSSION
As already stated in the Introduction, external morphological features within the Truncatelloidea usually lack the states which are unique or characteristic at least; almost always the range of variation is wide and overlaps between the species or even genera (e.g.FAlniowski 1987, szArowskA & FAlniowski 2008, 2011, FAlniowski et al. 2012, szArowskA et al. 2015).Thus, considering only morphology, P. magdalenae cannot always be distinguished from the other Greek Pseudamnicola.However, p-distance values (0.021-0.063) between P. magdalenae and the other presumed species of the Greek Pseudamnicola (szArowskA et al. 2015) are within the range of values recorded for congeneric species of Truncatelloidea.The long-lasting isolation of Kithira from the mainland or from any other island most probably resulted in species distinctness of P. magdalenae, clearly visible in the maximum likelihood tree (Fig. 12, see also: szArowskA et al. 2015: fig.1).The Pseudamnicola population in the spring at Viaradika in central Kythira may also belong to P. magdalenae.It is noteworthy that at Viaradika a relatively small spring was inhabited by dozens of thousands of specimens, but only three COI haplotypes were found there.On the other hand, the spring at Karavas formed a large pond, inhabited by very few Pseudamnicola, but as many as eight COI haplotypes were found there.This was the highest number of haplotypes found at any locality in the Greek Pseudamnicola (szArowskA et al. 2015).

Table 1 .
Shell trochiform with relatively high spire and simple outer lip, soft parts pigmented black, female reproductive organs with big bursa copulatrix and long loop of oviduct, penis simple, big, broad-Measurements of the holotype and n=10 paratypes Figs 1-8.Shells of Pseudamnicola magdalenae: 1 -holotype, 2-8 -paratypes.Bar equals 1 mm ly triangular without any outgrowth.Easily distinguished from P. macrostoma, geographically close and with a similarly-shaped shell, by the more triangular penis and the bigger bursa copulatrix.Shell spire in P. magdalenae lower than in P. brachia and higher than in P. exilis.Description.Shell (Figs1-8) trochiform, up to 3.04 mm high, having 4.2-5.2whorls, spire height approximately 16% of shell height and 24.5% of body whorl width.Teleoconch whorls moderately convex, evenly rounded, growing rapidly in diameter.Aperture circular, outer lip simple, parietal lip complete, umbilicus very broad or absent.Teleoconch with delicate growth lines, periostracum pinkish or white.Shell parameters of the holotype and ten paratypes are given in Table