ON TWO NEW CAVE PSEUDOSCORPIONS FROM DALMATIA , CROATIA ( CHTHONIIDAE AND NEOBISIIDAE , PSEUDOSCORPIONES )

Two new endemic species from the Jama Bezdan Pit between the villages of Komaji and Vignje, southeast from Ćilipi and Dubrovnik, Dalmatia (Croatia) — Chthonius (Chthonius) croaticus n. sp. B. Ćurčić & Rađa (Chthoniidae) and Roncus ragusae n. sp. B. Ćurčić & Rađa (Neobisiidae), are herein erected, described and thoroughly illustrated. Their main morphometric features and important diagnostic characters are analyzed and compared to their closest congeners, Chthonius (Chthonius) pristani Ćurčić and Roncus podaga Ćurčić, respectively.


INTRODUCTION
The Balkan Peninsula forms an irregular, inverted triangle of land that extends from central Europe in the north to the eastern Mediterranean in the south, and is bordered on both sides by the Adriatic, Ionian, Aegean, and Black Seas.The northern boundaries are not clearly demarcated by mountain chains, and are therefore not clearly defined.
Terrestrial cave dwellers in the Balkans (and in Croatia) are usually the descendants of a tropical epigean fauna that lived in Europe and North America at the end of Cretaceous and at the beginning of the Tertiary period.The tropical fauna subsequently disappeared from these regions: the species changed, were destroyed, or migrated towards the modern tropics.Only in caves have some species survived, since simultaneous karstification provided a wide variety of niches underground, which resulted in a huge new refugial zone for originally epigean species (Ćurčić, 1988).
However, the large and rapid climatic subversion that brought aridity to the Mediterranean area rendered it uninhabitable by humidity-dependant species, and the Balkan Peninsula, where sufficient moisture was preserved, offered shelter for the retreating and hygrophilic fauna.Among the main causes to have affected the history of cave invertebrates in Serbia, one should emphasize the effects of the karstification process.Very little is known about this process, and its interpretation must therefore be more or less hypothetical.
The major causes of the extraordinary variety of the troglobitic fauna of this region include: (a) the varied epigean fauna populating the Proto-Balkans in the remote past; (b) the continuity of continental phases in different areas of the Balkans; (c) the presence of mighty limestone beds and subsequent evolution of underground karst relief; (d) the succession of suitable climatic conditions favoring the colonization of subterranean habitats; and (e) the divergent differentiation of different lower and higher taxa in numerous isolated niches underground.
Generally speaking, the two new species, described herein, probably represent the descendants of some old fauna that inhabited present day Dalmatia in the remote past.
Galea (cheliceral spinneret) in the form of a small sclerotic knob (Figs. 4 and 16).Cheliceral palm bears five or six long setae and two additional small setae: movable cheliceral finger with one seta (Figs. 4,7,and 16).Fixed cheliceral finger with two distal large teeth, which are followed by a row of 7-11 small close-set and triangular denticles diminishing proximally and eventually replaced by small rounded teeth.Movable cheliceral finger has a small isolated distal tooth, one large tooth and a series of contiguous teeth that diminish in size proximally.Galeal seta inserted basal to the level of the large tooth on the movable finger (Figs. 7 and 16).The flagellum has nine blades, one small blade proximally and eight blades twice this length, more or less in pairs.The most distal members of the series are curved but all, to some extent, are pinnate on two sides.
Galea of a very small elevation of the finger margin.Fixed cheliceral finger with 6 setae, movable finger with one seta only.On the fixed finger, 10 distal teeth are very small and irregularly shaped, and these are followed by some rounded teeth, which are eventually replaced by some small teeth diminishing in size proximally.Movable finger with 8 distal denticles and a series of 3-5 teeth which are apically rounded.These teeth decrease in size from distal to proximal (Fig. 24).Flagellum of eight anteriorly pinnate blades (Fig. 22); the seven distal blades are of nearly equal size, but the most proximal blade is the smallest and dentate along its anterior margin.
Manducatory process with 4 long and acuminate setae.Trochanter with a tiny tubercle: pedipalpal tibia smooth (Fig. 18).A number of tubercles are borne by the pedipalpal femur anteriorly and laterally, and the chelal palm has distal granulations interiorly and exteriorly (Fig. 18).Chelal palm ovate (dorsal view: Figs. 17 and 18).Fixed chelal finger carries 75 small, contiguous and asymmetrically pointed teeth that reach the level of ib.Movable chelal finger with 65 teeth: only a few distal members are asymmetrically point-  2).Pedipalpal femur considerably longer than chelal fingers (Fig. 1).
Coxa I anteriorly and medially has a few small spines and transparent points.Tibia IV, basitarsus IV and tarsus IV each have a single tactile seta.Subterminal tarsal setae furcate, each branch with a few spinules.
Morphometric ratios and linear measurements are presented in Table 2.
Differential diagnosis -The new species is clearly differentiated from is closest congener R. podaga from Dalmatia in a great number of morphometric ratios and linear measurements (Table 2), as well as in the forms of different structures of the body (Figs.17-24).
Remarks -The Mediterranean pseudoscorpions are taxonomically an interesting faunal group, the greatest number of false scorpions concentrated in regions with a Mediterranean climate.Although data on the abundance of pseudoscorpion taxa in the humid tropics are lacking, preliminary observations suggest that the number of species is greater in the Mediterranean than in tropical rain forests.
According to Vandel (1964), it seems that the majority of Chthonius species are of relatively recent age.However, the cave-dwelling forms of Chthonius and Roncus comprise many phyletic lines, some less specialized, others highly adapted to the cave conditions.To trace their origin, biogeography, and evolution it is necessary to compare evidence of troglobitic species with that of the epigean forms from different habitats in Europe, and especially from Mediterranean and Dinaric habitats.
The material now at our disposal is the result of many collecting trips, complemented by material kindly given to us by different colleagues.The compilation of an inventory of pseudoscorpions in the Balkan Peninsula has indeed been very rewarding (Ćurčić, 1972, 1988;Ćurčić et al., 1993, 2004, 2010a, b, c;2011a, b;Hadži, 1937).This area seems to have been the center of an evolutionary explosion in the group of pseudoscorpions, similar to other arachnids (Deeleman-Reinhold, 1978).
The new species is a cohabitant with C. (C.) croaticus n. sp.It seems to represent an endemic and relict form in the Dalmatian coastland.
Table 1, and the form of different body structures in Figs.1-16.Differential diagnosis -The new species is clearly differentiated from Chthonius (Chthonius) pristani Ćurčić from Dalmatia in many important aspects: larger body size, larger and wider cephalothorax, in most morphometric ratios and measurements in millimeters (larger and different in the C. (C.) pristani, in the number of leg IV characteristics (Table 1), as well as in most shapes of different body structures (Figs.1-16).Material examined -Holotype female, from the Jama Bezdan Pit, between Komaji and Vignje, south-east of Ćilipi and Dubrovnik, Croatia; 7 August 2010, collected by one of us (TR).