On the biodiversity of pseudoscorpions in Croatia: Neobisium curcici (Pseudoscorpiones: Neobisiidae), a new cave-dwelling species from Dalmatia (Croatia)

The thorough analysis of a pseudoscorpion sample collected in the Jama pod Gažnovcem Pit, Stilja, near Vrgorac, Dalmatia (Croatia) resulted in establishing a new pseudoscorpion taxon – Neobisium curcici n. sp. The main diagnostic features of the type specimens studied are illustrated, carefully analysed and compared to the closest congeners. The taxonomic interrelationships and the geographic distribution of the new pseudoscorpion species are briefly discussed.


Introduction
The Dinaric karst that runs along the coast of the Adriatic Sea is abundant in subterranean formscaves, pits and ponors (Beier 1939;Ćurčić 1988). The subterranean fauna of the Dinaric karst is rich in pseudoscorpion species. Although many new taxa (species and genera) have been established in the past 30 years mainly by Ćurčić (1987, 1988) and Ćurčić et al. (2002, 2006, 2008, 2010, 2011, 2012a, b, 2013), it is still unsufficiently investigated. The representatives of the genera Chthonius C. L. Koch and Neobisium Chamberlin are known to inhabit caves and pits. Of these, the majority are endemic and relict troglobitic forms (Ćurčić et al. 2013).

Material and Methods
The careful examination of a small pseudoscorpion sample collected by one of us (TR) revealed the presence of a new taxon -Neobisium curcici n. sp. The type specimens were carefully dissected, then mounted on slides in a gum-chloral medium (Swan's fluid), and deposited in the Collection of the Institute of Zoology, University of Belgrade -Faculty of Biology, Belgrade, Serbia.

Systematic part
Neobisiidae Chamberlin, 1930Neobisium Chamberlin, 1930 NEOBISIUM CURCICI DIMITRIJEVIĆ, NEW SPECIES (Figs. 1-16; Table 1) Etymology -The new taxon is named after late Prof. Dr. Božidar P. M. Ćurčić, the most prominent Serbian arachnologist, whose studies laid the foundations to pseudoscorpiological investigations in the second half of the XX century in Serbia.
Material examined -Holotype male, a paratype male and a paratype tritonymph from the Jama pod Gažnovcem Pit, Stilja, near Vrgorac, Dalmatia, Croatia (Fig. 17), collected by hand under stones on 29 October 2014 by Tonći Rađa. It is not unusual to erect a new species on the grounds of a sparse material collected and examined, sometimes even on a single specimen available (Ćurčić et al. 2003;Henderickx and Vets 2000;Heurtault 1975;Mahnert 1982;Muchmore 2000).
Fixed pedipalpal chelal finger carries 137 or 141 teeth, while 123 or 128 teeth found on movable chelal finger (Fig. 6). The teeth on movable chelal finger do not reach the level of trichobothrium b, whilst the teeth on fixed chelal finger end before the level of ib (Fig. 6). Four trichobothria present on movable chelal finger and eight trichobothria on fixed chelal finger (Fig. 6).
Tibia IV, metatarsus IV and tarsus IV each carry a tactile seta. The tactile seta situated in the proximal part of tibia IV. Tactile setae on both metatarsus IV and tarsus IV located in the proximal thirds. Subterminal tarsal seta furcate, each branched, with a few spinnules. Tarsal claws sickle-shaped, smooth and slender (Fig. 7).
The linear measurements (in mm) and morphometric ratios of different body structures presented in Table 1.
Manducatory process (apex) of pedipalpal coxa with three setae. Pedipalpal articles as in male adults, elongate and smooth (Fig. 14). Pedipalpal femur and tibia elongate, widening distally. Chelal palm shorter than chelal fingers, tibia and femur. Fixed and movable pedipalpal chelal fingers with 94 and 84 small and asymmetrically pointed teeth, respectively. On movable chelal finger teeth end before the level of trichobothrium b (Fig. 15).
Distribution -On the grounds of the present knowledge, the newly erected pseudoscorpion species N. curcici is known to inhabit only it's locus typicus -Jama pod Gažnovcem Pit, Stilja, near Vrgorac, Dalmatia, Croatia. It is an endemic and a relict form. Further investigations of cave-dwelling fauna in Dalmatia may result in establishing new finding places of this species; if so, that will enable better understanding of the intraspecific variability.