ON TWO NEW CAVE PSEUDOSCORPIONS , CHTHONIUS ( CHTHONIUS ) PAGUS N . SP . ( CHTHONIIDAE ) AND RONCUS NAVALIA N . SP . ( NEOBISIIDAE ) , FROM THE ISLAND OF PAG , CROATIA

An analysis of the pseudoscorpion material from Croatia has supported the elevation of two taxa to full species rank: Chthonius (Chthonius) pagus n. sp. and Roncus navalia n. sp., both from Dalmatia; Croatia. Most diagnostic characters of the analyzed species are thoroughly described or figured. Some taxonomic interrelationships and features of geographic distribution have also been briefly discussed. Both studied taxa, which currently inhabit a cave on the Island of Pag in Dalmatia (Croatia), are probably endemics and relics of the Tertiary period.


INTRODUCTION
According to the degree of development of different karst phenomena, two different zones are easily distinguished within the Dinaric Region: a western zone bordered by the Adriatic Sea (the Holokarst), and a broader eastern zone, which is closer to the intermediate karst type.Thus, the Dinaric Holokarst embraces the limestone and dolomite terrains extending from Mt. Triglav to Lake Skadar, with an average length of about 700 km (Cvijić, 1926).These limestones and dolomites are of various ages.Along the Adriatic Coast, the limestone beds extend under the sea.
It is well known that favorable conditions for the development of karst were achieved as early as the beginning of the Paleocene, when parts of the Dinaric system had become dry land.During the Paleocene, fluvial and karst erosion removed much of the Mesozoic carbonate series under conditions of a tropical humid climate (Ćurčić, 1988).
The greatest number of pseudoscorpion taxa is concentrated in regions with a Mediterranean climate.Although data on the abundance of false scorpions in the humid tropics are lacking, preliminary observations suggest that the number of species is greater in the Mediterranean than in tropical rain forests (Vitali-Di Castri, 1973).Speciation in pseudoscorpions has not been studied in detail.However, the cave taxa comprise many phyletic lines, some less specialized, others highly adapted to the cavernicolous habitats.To trace their origin, biogeography and evolution it is necessary to compare evidence about troglobites with that of the epigean forms, especially from the Dinaric region (Croatia).
The material now at our disposal results from a field trip to the Island of Pag, Dalmatia (Croatia) in 2000.It includes two species new to science: Chthonius (Chthonius) pagus n. sp. and Roncus navalia n. sp.Both taxa are described, diagnosed and thoroughly illustrated.Generally speaking, they belong to Dinaric (or more precisely to the Dalmatian) area.
Setal designations follow Beier (1963) Abdominal tergites I -X and sternites IV -X uniseriate, entire and smooth.Tergites I -X with 4 -4 -4 -4 -6 -6 -6 -6 -6 -6 setae.Twelfth abdominal segment with two pairs of small setae.Pleural membranes granulostriate.Male genital area: sternite II with 11 median and posterior setae distributed in the form of a triangle.Sternite III with a median groove in the form of a V (each side with 9-10 setae), 10 posterior setae and 3 small setae along each stigma.Sternite IV with 8 posterior setae and 2 suprastigmatic setae on either side.Setal formula of sternites V -X is .Female genital area: sternite II with 10 median and posterior setae; sternite III with 11 posterior setae and 3 microsetae along each of the stigma.Sternite IV with 10 posterior setae and 2 suprastigmatic microsetae on either side.Setal formula of sternites V -X is [8][9].
Galea is a small, but with distinct elevation of the finger margin.Fixed cheliceral finger with six setae, movable cheliceral finger with one seta.On the fixed cheliceral finger, there is a large distal tooth, which is followed by six or seven small denticles decreasing in size from distal to proximal (Figs. 7 and 10).Flagellum of nine anteriorly pinnate blades, one small blade proximally and eight blades twice this length, more or less in pairs, distally.The most distal members of the series are curved but all, to some extent, are pinnate on two sides.
Apex of pedipalpal coxa (manducatory process) with two long and acuminate setae.Trochanter small, other pedipalpal articles moderately elongate (Figs. 1, 3, 8 and 9; Table 1).Chelal fingers almost straight of nearly equal length, with only their tips being slightly curved anteriorly (Figs. 1 and 8).Chelal palm elongated (Figs. 1,3,8 and 9).Fixed chelal finger with 33 (male) and 30 (female) small and contiguous teeth that extend from the fingertip almost up to the level of ist.Distal teeth are small and triangular, but eventually become apically rounded and smaller.Movable chelal finger with 39 (male) and 25 (female) small and contiguous teeth that do not reach the level of b.Distal teeth are triangular and retroconical, and these are replaced by the median rounded teeth which eventually become lower and narrower, ending in a lamella (Figs. 1 and 8).
Disposition of trichobothria is presented in Figs. 1 and 8.
Linear measurements and morphometric ratios are presented in Table 1, and the form of different body structures in Figs. 1 -14.
Differential diagnosis -The new species is easily distinguished from its closest congener, Chthonius (Chthonius) litoralis Hadži, by a number of qualitative (Ćurčić, 1988) and quantitative characteristics (Table 1; Ćurčić, 1988): it is also clearly distinct from C. (C.) litoralis in many morphometric ratios and linear measurements (Table 1).It is evident that the new species is an endemic taxon pertaining to the ancient faunal complex whose remainders are now inhabiting underground habitats.2) Etymology -After Navalia (Latin: shipyard, port or navalis), the present-day town near the type locality of the new species.
Material examined -Holotype male and allotype female, collected by Tonći Rađa, from the Ivča Jama Pit, near Novalja, Island of Pag, Croatia, 7 October 2000.These specimens of R. navalia were found together with a male and a female of Chthonius (Chthonius) pagus n. sp.
Cheliceral spinneret small, low and rounded.Cheliceral palm with six setae, movable finger with one seta.Movable cheliceral finger with 9 teeth that diminish in size both to the distal to proximal; both distal and proximal members are apically rounded and median teeth are somewhat triangular.Fixed cheliceral finger with 8-10 low teeth of irregular size and with one slightly larger tooth.These teeth also diminish from distal to proximal (Figs.22 and 29).Flagellum of eight blades; six to seven blades are of equal size and pinnate along their anterior margin; the following blades are somewhat shorter and pinnate along two-thirds or three-fourths of their anterior margins (Figs. 16).
Manducatory process with 4 long and acuminate setae.Trochanter with a small tubercle.Only chelal palm and pedipalpal femur granulate: there is a considerable variation in this character, especially on the femur (Figs. 15 and 23).Other pedipalpal articles smooth and somewhat elongate.Chelal palm ovate (Figs. 15,17,23 and 24).Fixed chelal finger with 63 (in both sexes) small, asymmetrically pointed and close-set teeth.Distal teeth are retroconical; median teeth are somewhat round-topped, and these eventually become close-set, low, and contiguous.The most basal teeth diminish in size proximally (Figs. 17 and 24).On the fixed finger, the teeth reach the level of ib and on the movable finger they almost reach the level of b.Chelal fingers longer than chelal palm.Pedipalpal femur longer than chelal fingers and longer than carapace (Table 1).
Trichobothriotaxy as in Figs. 17 and 24.Microsetae proximal to eb and es are lacking: instead, 5 or 6 small setae are developed distal to this two trichobothria (Figs. 17 and 24).
Anterior and median rim of coxa I with few chitinous points.Trochantic foramen small.Pedal tactile seta: tibia IV, basitarsus IV and tarsus IV each with a single tactile seta (Figs. 19 and 25).Subterminal tarsal setae furcate, each branch with few spinules.
Morphometric ratios and linear measurements are presented in Table 2 and the majority of qualitative features are thoroughly illustrated .

Differential diagnosis -From Roncus trojanicus
Ćurčić (inhabiting a cave near Trogir, Dalmatia) this new species is different in many qualitative (Ćurčić, 1988) and quantitative features (Table 2).Namely, the two taxa differ in many morphometric ratios and linear measurements (Table 2), as well as in the form of almost all body structures .Needless to say, R. navalia n. sp. is probably a remainder of an old epigean fauna, which colonized the subterranean milieux and lives there since then.The type locality of R. navalia is also inhabited by C. (C.) pagus n. sp.

Distribution -In Croatia, in caves.
It is pertinent to note that the faunal exchange between Dinaric caves (where Croatian under-ground habitats also belong) and those found elsewhere has been very limited, especially in advanced phases of the karstic evolution.This is due to their geographical position and to the adaptation of their inhabitants to specific life conditions.Cave-dwelling pseudoscorpions were thus enabled to compete successfully with new immigrants.However, the life conditions in caves must be considered as relative.These conditions have certainly changed during cave existence, but not in such a manner as to have provoked the disappearance of the majority of relicts.In addition, such changes have favored the autochthonous evolution of different taxa living underground.
We have every reason to assume that the pseudoscorpion analyzed here evolved from the ancient circum-Mediterranean fauna, its origin to be sought in the Dinaric region.The underground habitats there succeeded each other in a continuous manner up to our times.More ancient caves disappeared, whilst new ones were formed, thus favoring the survival of their fauna.This continuity of different niches underground has certainly played an outstanding part in the preservation of old pseudoscorpion elements, including the taxa described herein.
Each study of cave pseudoscorpions inhabiting the Dinaric Karst offers further proofs of their great age and different origin.Such species and genera represent the last vestiges of an old fauna, which found shelter in the subterranean domain of the Dinarides, Balkanides and elsewhere (Ćurčić, 1972, 1988;Ćurčić et al., 1993, 2004, 2010a, b, f, g;2011a, b, c, d, h;Hadži, 1937).
Etymology -After its type locality: in Latin, Pagus is the name of the village which existed on the territory of the present-day Island of Pag.Material examined -Holotype male, from the Ivča Jama Pit, Pag, Island of Pag, Croatia, 7 October 2000, collected by one of us (TR); allotype female, collecting data as in holotype.This locality is also inhabited with Roncus navalia n. sp.Description -Carapace wider than longer(Figs.6and14);epistometriangular,with some indentations(Figs.6 and 14).Two anterior eyes and two posterior barely visible eyespots.Setal formula: 4 + 6 + 6 + 4 = 20 (in both sexes).Carapace reticulate throughout.A single preocular microseta is carried in each preocular recess(Figs.6 and 14).

Table 2 .
Linear measurements (in millimeters) and morphometric ratios in Roncus navalia n. sp., and R. trojanicus Ćurčić from Croatia.The distinctive traits of Roncus navalia n. sp. are in bold numbers.Abbreviations: M = male, F = female.