RONCUS RADGOST N. SP., R. JAREVID N. SP., AND R. CRNOBOG N. SP.: THREE NEW CAVE DWELLERS FROM EASTERN SERBIA (NEOBISIIDAE, PSEUDOSCORPIONES)

Three new endemic species of the genus Roncus L. Koch (Neobisiidae, Pseudoscorpiones) from eastern Serbia have been erected, described and fully illustrated. Their main characters and important diagnostic features have been analyzed and compared to those of their closest congeners from the area studied.


INTRODUCTION
Biogeographically, some genera and species of the Balkan (Serbian) troglobites are characterized by a disjunctive distribution.This type of partition can be attributed to some paleogeographic and climatic changes, since the distribution of these troglobites and their closest epigean relatives correspond to the distribution within the old Mediterranean dryland that existed at the very beginning of the Tertiary (Ćurčić and Dimitrijević, 1986).
Analysis of the once existing fauna helps in interpreting the origin and history of some Balkan troglobites.The primordial populations colonized the Proto-Balkans at the beginning of its existence.Subsequently, this gave birth to a number of phyletic lineages.Evidently, there existed rich epigean Paleogene and Neogene faunas in Eurasia, and their disappearance from some parts is due not only to unfavorable changes in climate, but also to the lack of migration routes or possibilities of finding shelter (Tollmann, 1968).
From the biogeographic point of view, the Mediterranean, the Pannonian and the Pontocaspian region are the main refugial zones in Europe.It is not easy to understand the origin and history of endemic faunas, particularly pseudoscorpion fauna in Balkan (Serbian) subterranean habitats, because they represent an adaptive and selected fauna.The colonization of their underground habitats must have begun a long time ago and passed through successive stages during different geological times, together with the development of different karstic phenomena.
Study of the cave pseudoscorpions of the karst in Serbia has offered further proof of their great age and different origin.These species and genera represent the vestiges of an old fauna that found shelter in the underground domain of Serbia and its adjoining regions.Apart from this, it is apparent that specific aspects of geomorphological and climatic events in the Balkan, together with peculiarities in the historical development of the fauna in Serbia, caused the peninsula to become the main center of dispersion and colonization of species and group of species, i.e. the main source for the revitalization and genesis of biological diversity not just in the Mediterranean region, but throughout all of southern Europe.
In this study, careful examination of some cave pseudoscorpions from eastern Serbia resulted in the establishing of three more species of false scorpions, which probably belong to endemic and relict fauna that inhabits the area studied.
Setal designations follow Beier (1963) 1) Derivatio nominis -This species is named after the polycephalic Slav god with one human and one lion head (the god of hospitality) (Vasiljev, 1928).
Type locality -Holotype male from the Golema Porica Pit, Mt.Rtanj, eastern Serbia, collected by Srećko Ćurčić and Dragan Antić, 29 May 2012.The specimen of R. radgost n. sp. has been collected from under stone, in total darkness.The type specimen has been deposited in the collection of the Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia.
Hydrogeologically, the corridor system of the Golema Porica Pit came into existence by the action of a subterranean watercourse.The complex has already lost its permanent hydrographic function due to the process of intense karstification of the region.
Abdomen -Tergite I carries six setae, but thereafter there is a gradual increase in the number of chaetae borne on the succeeding tergites, with a maximum of 11 setae from tergite V onwards (6 -9 -10 -10 -11 -10 -11 -11 -11 -10) in the holotype.In the male, sternite II carries a cluster of 14 setae, thinning out anteriorly.Sternite III of the male carries nine posterior and four anterior setae, while sternites IV -X carry 10 -13 -13 -13 -14 -13 -12 posterior setae.Normally, two or three microsetae are carried along each of the stigma III and three such setae along each of the stigma IV.Sternite XII with two pairs of small setae.
Chelicerae -The spinneret is represented by a low hyaline tubercle.The movable and fixed finger of the chelicerae carry 11 and 13 teeth, respectively.Six setae occur on the chelicera, and only one on the movable finger.Cheliceral dentition as in Fig. 8. Flagellum eight-bladed, characteristic of the genus (Fig. 2).
Pedipalps -Apex of pedipalpal coxa with four long setae.The movable finger of the chela carries 55 teeth and there are 54 teeth on the fixed finger (Fig. 1).The most distal pointed teeth on the movable finger give way to teeth with rounded tops and these are gradually replaced proximally by short flattened teeth.On the fixed finger, the first few teeth are pointed, slightly asymmetrical, and then there is a gradual transition to the square-topped teeth of the proximal region (Fig. 1).The granulations already noticed on the anterolateral surface of the femur also occur on the palm of the chela (Fig. 3).Pedipalpal tibia tulip-like and smooth.
Legs -Coxa I carries six or seven chaetae, coxa II two, coxa III five, and coxa IV six chaetae.
Type locality -Holotype male from the Gornja Lenovačka Pećina Cave, village of Lenovac, Mt.Tupižnica, eastern Serbia, collected by Srećko Ćurčić and Dragan Antić, 26 June 2012.The type specimen has been deposited in the collection of the Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia.
Flagellum of eight blades, pinnate along their anterior margins, characteristic of the genus (Fig. 13).
Morphometric ratios and linear measurements are presented in Table 1.
Remarks -From R. radgost n. sp., R. crnobog., as well as from R. pljakici Ćurčić, R. sotirovi Ćurčić, R. timacensis Ćurčić, and R. remesianensis Ćurčić, the new species differs in almost all important structures, as in the majority of morphometric ratios and linear measurements (Table 1).
Type locality -Holotype male and paratype female from the Ogorelička Pećina Cave, village of Sićevo, Svrljiške Planine Mts., eastern Serbia, collected by Srećko Ćurčić and Dragan Antić, 26 June 2012.The type specimen has been deposited in the Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia.
Legs -Tibia IV, basitarsus IV, and tarsus IV each with a single, long tactile seta (Figs. 19 and 27).Subterminal tarsal setae furcate, each branch with a few tiny spinules.
Tactile seta ratios and measurements as presented in Table 1.
Remarks -According to the present knowledge (Figs.1-32, Table 1), the new species differs from all known cave congeners inhabiting Serbia, i.e. the central part of the Balkan Peninsula.The establishing of new Roncus species in Serbia confirms the opinion (Ćurčić, 1992) that the taxonomy of this group is still far from being complete.On the grounds of available data it is evident that the genus is in the process of an intensive radiation and divergent differentiation into new species in Serbia (as well as in regions bordering on Serbia) (Ćurčić 1973, 1984;Ćurčić and Beron, 1981;Ćurčić and Dimitrijević, 2009;Ćurčić et al., 2010, Ćurčić et al., 2012a, b, c, d, e, f).