NEOBISIUM DELTSHEVI (NEOBISIIDAE, PSEUDOSCORPIONES), A NEW ENDEMIC CAVE-DWELLING PSEUDOSCORPION FROM EAST SERBIA

A new endemic cave-dwelling pseudoscorpion species from the Seselačka Pećina Cave, village Seselac, nr. Soko Banja, East Serbia is presented, described and illustrated. Its main morphometric characteristics and important diagnostic features are analyzed and compared to those of its closest congener Neobisium carpaticum (Beier, 1930) from Serbia.

At present 8 cave-dwelling species are known to inhabit different underground habitats in Serbia.Based on the knowledge of the biodiversity of the genus Roncus as well as some other invertebrate groups (spiders and coleoptera) (Ćurčić, Deltshev & Gueorgiev 2005;Ćurčić 2007) we are of the opinion that the number of cavernicolous Neobisium species by far exceeds the present known number of taxa pertaining to this genus.Further investigations will most likely confirm this opinion.
A recent visit to the Seselačka pećina Cave, near the village Seselac nr.Soko Banja, East Serbia resulted in the collection of a small sample of pseudoscorpions.Careful examination of the collected pseudoscorpion material revealed the presence of a new taxon Neobisium deltshevi.The new species represents an endemic form that inhabits a cave in East Serbia.Thus, the number of known cave-dwelling pseudoscorpion species in Serbia has risen to nine.  1 and 2) Description -Male.Carapace slightly longer than broad (Fig. 8, Tab.1).Epistome small and rounded    (Fig. 7); 22 setae present on the carapace.Anterior row bears 4 setae while the ocular, intermedian and posterior row carry 6 setae each (Fig. 8).Two pairs of eyes developed, of these the anterior pair is distinctly larger than the posterior pair (Fig. 8).
Cheliceral galea low (Fig. 2), 6 and 1 seta are carried on the fixed and movable cheliceral fingers respectively (Fig. 2).The fixed finger bears 11 teeth and the movable finger 7. Flagellum 8-bladed, only two distal blades are pinnate along the anterior side.All other blades are smooth and acuminate.The proximalmost blade is the smallest (Fig. 6).Chelicera is 1.90 times longer than broad.
Trichobothriotaxy: Eight and four trichobothria are present on the fixed and movable pedipalpal fingers respectively.Trichobothria EB, ESB, B and ISB on the finger base.Trichobothrium EST equidistant from IT and ET.Trichobothrium ST closer to T than to SB; SB closer to B than to ST.
Chelal finger longer than the chelal palm (Tab.1).The pedipalpal chelal length to breadth ratio is 4.30.Pedipalpal femur is 4.29 times longer than wide.The pedipalpal tibia is 2.70 times longer than broad.
Morphometric ratios and linear measurements (in mm) are presented in Table 1.
Description -Female.Carapace slightly longer than wide (Fig. 16) with a small epistome with a rounded top.As in the male, the carapace carries almost the same number and disposition of setae in setal rows (21-22).In the paratype female 5 setae are present in the posterior row.Two pairs of eyes of uneven size present.The anterior pair of eyes larger than the posterior pair (Fig. 16).
Cheliceral galea low (Fig. 10).As in the male, the same number of seta (6 and 1) developed on the fixed and movable cheliceral finger.11 and 9 teeth present on the movable and fixed cheliceral finger.Flagelum 8-bladed.Chelicera is 1.54 (1.96) times longer than broad.
Manducatory process of the pedipalpal coxa with 5 seta.Pedipalpal articles smooth (Fig. 12).Fixed and movable chelal finger bear somewhat larger number of teeth than in the male (76 and 68 respectively).Eight and four trichobothria present on the fixed and novable chelal finger.Chelal finger 1.36 times longer than chelal palm (Tab.1).The pedipalpal chelal length to breadth ratio is 3.85.Pedipalpal femur is 4.35 times longer than broad.The pedipalpal tibia length to breadth ratio is 2.56.
Differential diagnosis -Males and females of Neobisium n. sp.can be distinguished from their corresponding counterparts of phenetically close congener Neobisium carpaticum Beier in several aspects.These differences comprise the smaller dimensions (size) of various body parts in both sexes such as: carapace (shorter vs. longer); chelicerae (shorter vs. longer); pedipalps (including all pedipalpal articles) (shorter vs. longer) and leg IV (shorter vs. longer).In N. deltshevi there are no preocular microsetae as in N. carpaticum.Furthermore, more important differences between these two species are displayed in the different morphometric ratios of body structures.
These differences are more obvious in the female specimen than in the male.
In the male, differences in the ratios of body parts are less pronounced than in the female.These differences can be clearly demonstrated in the smaller values for pedipalpal chelal length to breadth ratio (3.54-4.05 in N. carpaticum vs. 4.30-4.53 in N. deltshevi); pedipalpal chelal palm length to breadth ratio (3.53-4.05 in N. carpaticum vs. 4.30-4.53 in N. deltshevi); and leg IV TS ratio of basitarsus (0.11-0.16 in N. carpaticum vs. 1.175-0.20 in N. deltshevi).
The tergal setation (I-X) in both sexes of the compared species has similar or identical values (Tab.2).Sternal counts in the male specimen display slight differences on the sternite II and III.In N. carpaticum sternite II bears 13-16 stetae vs. 8 setae in N. deltshevi, whilst sternite III in N. carpaticum carries 30-38 setae vs. 29 setae in N. deltshevi.
Taking into account the above-mentioned differences of various body structures as well as the morphometric ratios for several body parts, we are of the opinion that N. deltshevi.represents a species closely related to N. carpaticum.Moreover, it seems likely that the newly established species originated from N. carpaticum.It represents a descendant of a population of N. carpaticum that has populated the Seselačka pećina Cave and is still going through the process of adaptation to cave conditions (reduction of the posterior pair of eyes).
Distribution -According to present knowledge, the newly established species inhabits only the Seselačka pećina Cave in East Serbia.It is regarded as an endemic neobisiid species from eastern Serbia (one that is still undergoing the process of adaptation to cave conditions).
Specimens examined: -Holotype male and female and paratype male and female from the Seselačka pećina Cave, village of Seselac, nr.Soko Banja, East Serbia collected on 26 September 2009 by Srećko Ćurčić and Romana Bosanac.The holotype specimens are deposited in the collection of the Institute of Zoology (IZB), Faculty of Biology, University of Belgrade, Belgrade, Serbia.Etymology: -The new species is named after Dr. Christo Deltshev, a world-wide known arachnologist and speleobiologist.SYSTEMATIC PART NEOBISIIDAE J.C. CHAMBERLIN, 1930 NEOBISIUM Chamberlin, 1930 NEOBISIUM DELTSHEVI NEW SPECIES (Figs. 1-16; Tables
Trichobothriotaxy: Trichobothria EB, ESB, IB and ISB positioned on the finger base.Trichobothrium EST slightly closer to ET than to IT. Trichobothrium IST closer to EST than to ISB.
Diagnostic characters of N. deltshevi n. sp. are bolded.
Diagnostic characters of N. deltshevi n. sp. are bolded.