CHTHONIUS ( EPHIPPIOCHTHONIUS ) RHIZON N . SP . : A NEW CAVE FALSE SCORPION FROM THE BAY OF KOTOR ( CHTHONIIDAE , PSEUDOSCORPIONES )

A new cave pseudoscorpion from Montenegro, Chthonius (Ephippiochthonius) rhizon n. sp., is described. The newly erected taxon is endemic to the Bukarička Pećina Cave, Knezlaz, Montenegro. Its taxonomic relationship with the phenetically close congeners, including comparative morphological traits, is described.


INTRODUCTION
In the present study, material from a sample of pseudoscorpions collected in the Bukarička Pećina Cave, nr.Risan, Montenegro, has been examined.This sample contained a new taxon -Chthonius (Ephippiochthonius) rhizon n. sp.To complete the study of Balkan Ephippiochthonius species, the material of other species was reexamined in order to define their precise taxonomic rank.
The new species described in this paper is an endemic and relict form, inhabiting underground habitats in the southern part of the Balkan Peninsula.
Description -The anterior carapacal border is wider than the posterior one, and the dorsal side of the cephalothorax is longer than broad (Fig. 6, Table 1).
Neither eyes nor eyespots are developed (Fig. 6).The anterior carapacal border is only slightly convex and without a differentiated epistome (Fig. 4).However, there exist tiny indentations, particularly between the two anterior and median setae.Such slight indentations can be seen on the margin almost up to the lateral anterior setae.The carapace has 18 setae arranged in five rows; four anterior, six 'ocular' , four median, two intermedian and four posterior.In the posterior row, only two median setae are long (Fig. 6).Two small setae are carried in each 'preocular' recess.
The cheliceral spinneret (galea) is represented by a tiny hyaline tubercle (Fig. 9).There is a small isolated tooth distally on the movable cheliceral finger.The first large tooth is contiguous with a series of smaller teeth that end below the insertion site of the galeal seta (gl).On the fixed finger, the teeth extend back, diminishing abruptly in size, below those on the movable finger (Fig. 9).
The movable finger carries one large galeal seta (gl) and six setae on the palm of the chelicera.The cheliceral flagellum consists of nine blades, 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.
Four trichobothria are carried on the movable and eight on the fixed chelal finger.The contour of the chelal palm on the dorsal side is depressed in front of these two trichobothria -isb and ib (Figs. 1 and 2).The teeth of the fixed finger (21-22) are distributed evenly along its inner length; of these, the distal and median teeth are prominent because of their pointed tips and the remaining are no more than small projections, proximally.The movable finger has a pronounced apodeme.This finger has 21-24 teeth; the first six or seven resemble the distal teeth of the movable finger.Proximally, the teeth decrease in size until the last six are small eruptions at the base of the finger (Fig. 1).In addition, the fixed chelal finger carries an obvious small accessory tooth at the extreme distal end of the podomere.
The measurements of the different podomeres of leg IV, as well as the tactile seta ratios are presented in Table 1.Tibia IV, metatarsus IV, and tarsus IV each carry a long tactile seta.The claws are slender, smooth and sickle-shaped.Pleural membranes granulostriate.The last segment bears two pairs of microsetae.
Remarks -The new species differs considerably from all its phenetically close congeners in morphometric ratios, linear measurements, form of different body structures, absence/presence of eyes, absence/ presence of heterodentition on chelal palm, the carapacal and sternite setation, the number of chelal teeth, the distribution areas, and in many other respects.
The diversity of underground pseudoscorpions precludes a simplified treatment of its ecology.We are still discovering and establishing, like in this paper, a number of microhabitats of soil pseudoscorpions in these ecosystems (Ćurčić, 1972, 1988;Ćurčić et al., 1993, 2004, 2010a, b, c, d, e, f, g;2011a, b, c, d, e, f, g, h, 2012a, b;Hadži, 1937).The mechanisms of habitat separation are many and different.The diversity of the pseudoscorpions of the soil fauna can be viewed as the totality of the various effects, although it is clear that the indicated effects operate more restrictively and selectively on the level of individual populations.