RONCUS MELEDAE N . SP . AND NEOBISIUM OCULATUM N . SP . , FROM THE ISLAND OF MLJET , DALMATIA ( NEOBISIIDAE , PSEUDOSCORPIONES )

Two species of troglobitic false scorpions, Roncus meledae n. sp. and Neobisium oculatum n. sp. (Neobisiidae, Pseudoscorpiones), are described from inside underground habitat, i.e. the Jama Na Žutim Kokom Cave, the Island of Mljet, Dalmatia, Croatia. The analyzed pseudoscorpions prove to differ from all other congeners. It is possible that the subterranean pseudoscorpions analyzed represent relicts of an old north tropical faunal pattern of the Mediterranean.


INTrODuCTION
The Mediterranean is a 3.600 km-long inter-continental sea, from Gibraltar to the coast of Levant, all of it being situated on the same latitudinal belt.Despite this, the oceanographic environment and its biota show a very clear west-to-east gradient which is perhaps better seen as NNW-SSE.As the sea penetrates eastward, it encounters more and more continental and dry climate.The northwest is mountainous and rich in river input and the Southeast is dominated by low topography and limited freshwater inflow.
The Adriatic Sea is no part of this west -east gradient.Its inclusion in such discussions only confuses.This narrow, shallow sea, extending northwards into a cooler climate, abundantly supplied with nutrients by the river Po, has its own hydrography and biotic history.
Perhaps nowhere else has the history of biogeographic evolution been so closely interwoven with major environmental changes as in subrecent Mediterranean.Climate events, sea level changes and, not least, the tectonic conflagrations, have all left their mark, often recorded in memory and history.
The problems related to the changing sea levels of the Tertiary -the low glacial level of +/-150 m below the present one, have had important biogeographic consequences.The northern half of the Adriatic repeatedly felt dry.Tectonics and volcanism were also very active during the Tertiary.The coalescence of islands, or collapse of island connections, movements of tectonic uplifting of new islands and collapse of old ones were associated by destructive tsunamis.The last were probably the reason for several years of climate disruptions.
The Mediterranean Sea is a "cultural basin" (Aravantidis et al., 2003), the most familiar and possibly, despite all the restrictions, with the best species inventory among the seas of the world.It is not surprising, therefore, that it has a high percentage of endemism.
Palaeoendemic pseudoscorpions are taxa of a tropical stock (Ćurčić, 1988), which were left behind from the Mesozoic or early Cenozoic and survived in isolation after the ancient distributional continuum was disrupted.It is not easy to analyze the origin and history of the endemic pseudoscorpions of the Dinaric underground habitat because they represent an adaptive and selected fauna.The colonization of the Dinaric subterranean milieu must have begun a long time ago and passed through successive stages during the different geological times, including the development of karstic phenomena.Therefore, it is probable that the Dinaric area was colonized at the beginning of its existence by false scorpions, which already inhabited Mediterranean forests.
The study of the cave pseudoscorpions inhabiting the Dinaric karst has offered further proofs of their great age and probably different origin.These species and genera represent the last vestiges of an old fauna that found shelter in the underground domain of the Balkans and elsewhere (Ćurčić, 1986; 1988).
The discovery (1996) of some pseudoscorpions new to science revealed an underground ecosystem, that of the Jama Na Žutim Kokom Cave, Island of Mljet, middle Dalmatia, Croatia.These species have been described as Roncus meledae n. sp. and Neobisium oculatum n. sp.(both taxa inhabit the same cave).
Here is an exact study of the newly found species -Roncus meledae n. sp.  and Neobisium oculatum n. sp. .
Setal designations follow Beier (1963) Description -The dorsal side of the cephalothorax is with no eyes and, in general, it is longer than wider (Fig. 1, Table 1).The anterior margin of the carapace is wider than the posterior and the carapace resembles an irregular quadrate (Fig. 5).The epistome is low and apically rounded (Figs. 4 and 5).The carapace bears 27 setae and these lie in four rows.Four setae constitute the anterior row, seven setae belong to the 'ocular' series, ten to the median and intermedian rows and six setae constitute the posterior series.No preocular setae are developed in each preocular recess (Fig. 5).
The setal formula of abdominal tergites I -X can be expressed as 7 -11 -10 -11 -11 -11 -11 -12 -11 -9 and is remarkable for the lower number of setae on tergite I. Sternite II of the male has 17 setae along the posterior sternal margin; sternite III carries 8 anterior and 12 posterior and 3 suprastigmal microsetae on either side.The fourth sternite has 10 marginal setae and 3 small setae along each of the stigma.Sternites V -X carry 15 -16 -14 -14 -13 -12 posterior setae (Fig. 8).The cheliceral spinneret is represented by an extremely low sclerotic knob on the movable finger (Fig. 7).Immediately below, there are teeth of irregular size which diminish both proximally and distally.On the fixed cheliceral finger, the teeth are smaller.Fixed cheliceral finger with six setae, movable cheliceral finger with a single seta only (Fig. 7).
The measurements and morphometric ratios of the different structures, as well as the tactile seta ratios, are presented in Table 1 and in Figs.1-8.The tibia IV, metatarsus IV and tarsus IV each carry a long tactile seta (Fig. 3, Table 1).
Remarks -The new species is easily distinguished from its congeners, Roncus pripegala and R. insularis, from Dalmatia, Croatia, in the length of the pedipalps and pedipalpal articles, the ratio of length-to-breadth of pedipalpal femur, ratio of tibial length-to-breadth, in the chelal length-to-breadth ratio, length of chelal palm and length of leg IV (Table 1).From R. pripegala, R. meledae n. sp.differs in its pedipalpal articles, in the carapacal setation, tergal and sternal setation, number of teeth on fixed and movable chelal finger, as well as in the less elongated pedipalpal podomeres.R. meledae n. sp.differs considerably from R. insularis in the tergal and sternal setation, number of chelal teeth, form of the pedipalps, as in the number of morphometric ratios and linear measurements.Furthermore, the new species is clearly distinct from R. insularis in pedipalpal length, pedipalpal femur length-to-breadth ratio, patellar length-to-breadth ratio, chelal length-to-breadth ratio, chelal length-tobreadth ratio, total length of leg IV and in the tibia IV length-to-breadth ratio (Table 1).
Morphometric ratios and linear measurements are presented in Table 1.
Distribution -It is probable that the distribution of the new subterranean Roncus species from the island of Mljet is relict of the Miocene northern areas of once tropical or subtropical regions.Its present area probably preserves the old biogeographical dis-tribution and is therefore in line with contemporary records worldwide (Ćurčić, 1972, 1988;Ćurčić et al., 1993, 2004, 2010a, b, c, d;2011a, b, c, h;Hadži, 1937).2) Etymology -After the presence of two small eyes on each carapacal side.
Galea is a slight elevation of the finger margin (Figs. 15 and 22).Fixed cheliceral finger with six, movable cheliceral finger with a single seta.Flagellum of eight or nine blades, first eight of nearly equal size and a most proximal blade smaller than the others.Other flagellar blades pinnate along their anterior margin (Figs. 11 and 19).
Tibia IV with a single, basitarsus IV and telotarsus IV each with two tactile seta.
Morphometric ratios and linear measurements are presented in Table 2.
Remarks -The species Neobisium oculatum n. sp.differs clearly from its congener, N. dalmatinum, in the presence/absence of eyes, setation of tergites I -X and setation of sternites II -X, in the size of the galea, the form of the pedipalps, chelal dentation and in the disposition of trichobothria on both chelal fingers.Finally, in the new species the basitarsus carries two tactile setae (three N. dalmatinum) and telotarsus IV has two such setae (as in N. dalmatinum).