Chondrina tatrica Ložek , 1948 : new species for the Romanian fauna ( Gastropoda : Chondrinidae )

Chondrina tatrica Ložek, 1948 is reported for the first time for Romania. The species was thought to be endemic to the Western Carpathian Mountains. The Romanian locality (Boga valley, Bihor County) is situated approximately 260 km from the nearest known site of the species in a straight line. The zoogeographical significance of this finding and the possible route of the ancestors of C. tatrica to the Carpathians is discussed.


Introduction
The genus Chondrina Reichenbach, 1828 is widely distributed in Europe from the Iberian Peninsula and the neighbouring African coastline (Morocco) as far as the Caucasus Mountains and Iran, from North Africa to Middle Europe.Some isolated populations of Chondrina arcadica clienta (Westerlund, 1883) have been reported from several southern Swedish islands as well (GiTTenBeRGeR 1973, kokshooRn & GiTTenBeRGeR 2010, WelTeR-schul-Tes 2012).However, the majority of the species inhabit Southern Europe.The genus is most diverse in terms of number of species in the Iberian Peninsula, where several endemic species are known (kokshooRn & GiTTenBeRGeR 2010).The Carpathian Basin is inhabited by only two species, namely the widely distributed Chondrina arcadica clienta, and Chondrina tatrica Ložek, 1948(Ložek 1948).The latter species has been reported from a relatively narrow area in the Western Carpathian Mountains only.Its area includes the Great Fatra Mts., the High and Low Tatra Mts., the Slovak Paradise, the Muráň Plateau, and the Slovak Karst area (lisický 1990).Most populations are known from Slovakia, but the species reaches Poland on the northern edge of the High Tatras and Hungary in the Aggtelek Karst (FaRkas 2008)

Results
During a faunistic survey in the Boga valley (=Valea Boghii, Bihor Mountains) in 2011, a soil sample was collected at the base of a huge limestone rock named Piatra Dracului.This rock is probably the highest in the Valea Boghii area, and has an enormous exposed surface facing to the south.The soil sample contained several empty Chondrina shells.Six of them were obviously different to the shells of C. arcadica clienta which were also present in the sample.The main differences were the following: the general shape of the shells were rather oval, the shell surface was smoother, with overall much weaker teeth in the aperture.Comparing the shells with Slovakian C. tatrica specimens we found no notable differences.Thus, these Romanian shells (Fig. 1) have been identified as Chondrina tatrica.The measurements of the Romanian shells are the following: height: 6.00-6.27mm, width: 2.40-2.53mm (n=4).As a comparison, keRney et al. (1983) reports 6.0-7.5 mm as shell height and 2.2-2.8mm as shell width.During a second trip in 2012 we were aiming to find living individuals, but we were not successful.In 2012, Péter Subai also collected empty shells at the same site.

Microhabitat of Chondrina tatrica
We have no direct observation regarding the microhabitat preference of the Romanian Chondrina tatrica populations, therefore we can rely on our experience in Hungarian and Slovakian sites.In those countries the species prefers huge, vertical limestone rocks, and living individuals can be found in rock surfaces directly exposed to sunlight.In the Romanian site we hypothesise that the species lives on high cliffs which are hardly accessible for collectors.

Biogeography of the Boga valley
The Boga valley is the most significant valley system of the western side of the Bihor Mountains.Because of the relatively low elevation and the vicinity of the Great Hun- The rock-dwelling Alopia genus is represented by Alopia bielzii tenius (E. A. Bielz, 1861) in some parts of the Apuseni Mountains, and it has been reported from the Boga valley as well (deli & domokos 2011).Interestingly, Alopia bielzi clathrata (E. A. Bielz, 1856), which is an isolated population of the same species, is known from the Slovak Karst.This is the northernmost representative of the genus Alopia.This Alopia species shows strikingly similar distribution pattern to that of Chondrina tatrica (Fig. 2), because both species occur in the Apuseni Mountains and in the Western Carpathians without known populations in-between.

Origin of Chondrina tatrica
In the molecular phylogeny of kokshooRn et al. ( 2010) Chondrina tatrica formed a clade ("Group A") together with C. megacheilos and C. multidentata (Southern Alps) and C. spelta (Western Balkans).The resolution of the phylogenetic tree was not sufficient to tell which of the two species is closer related to C. tatrica.Knowing the closest relatives of C. tatrica, we can assume that the ancestors of C. tatrica could have arrived to the Western Carpathians from two different directions.According to the first hypothesis, ancestors of C. tatrica are originated from the southern part of the Alps.Migration between the Alps and the Western Carpathians are known in some cases of land snails.For example, it probably happened several times in the case of also calciphilous Orcula dolium (Draparnaud, 1801) (haRl et. al. 2014).The second hypothesis suggests that they have arrived from the Western Balkans.This route has been suggested in several genera, such as Alopia and Mastus (FehéR et al. 2013).Without knowing the Romanian locality presented here, both hypotheses seemed to be possible because the current distribution of C. tatrica is in similar straight line distances from both areas.The presence of Chondrina tatrica in the Apuseni Mountains, however, suggests that the ancestors of the species could have followed the inner chains of the Carpathians to reach their present distributional area.