Checklist of the pseudoscorpions ( Arachnida : Pseudoscorpiones ) of Montenegro

Based on current knowledge, it can be stated that a total of 50 species and seven subspecies of pseudoscorpions have been recorded in Montenegro. Out of six pseudoscorpion families and eight genera known in Montenegro, the family Neobisiidae (with two genera – Neobisium Chamberlin, 1930 and Roncus L. Koch, 1873) is the most abundant (with 34 species and seven subspecies). The pseudoscorpion fauna of Montenegro is characterized by a high degree of endemism (72% of all recorded species and 100% of all recorded subspecies are endemics), as well as by the presence of numerous cave-dwelling forms (58% of species and 57.14% of subspecies). According to their current distribution, these taxa can be relegated to nine zoogeographical categories grouped into six complexes (cosmopolitans, widely distributed taxa, European taxa, Mediterranean taxa, Europeo-Mediterranean taxa and endemics). Professor Boţidar P.M. Ćurĉić greatly contributed to a better understanding of the biodiversity of this arachnid group in Montenegro. Alone or with collaborators, he erected 52% of all pseudoscorpion species inhabiting Montenegro.


Introduction
The number of known pseudoscorpion species in the world is constantly increasing.Thus, according to Savory (1977), 1,000 species were known to science in 1939, while in the next 25 years this number doubled itself (Ćurĉić et al., 2004b).Harvey (1990) recognized 3,064 pseudoscorpion species belonging to 434 genera.Meanwhile, the same author recently reported 3,498 pseudoscorpion species at the global level (Harvey, 2011).The number of known species varies from country to country and depends on many factors.A low number of registered species in some countries can be attributed to the fact that this group of small arachnids has not yet been sufficiently investigated there.Their small body size and cryptic way of life also hinder studies on these tiny arachnids.The Balkan Peninsula is one of the regions of Europe with a very rich and versatile pseudoscorpion fauna (Vandel, 1964;Vitali-di Castri, 1973;Ćurĉić, 1988;Harvey, 2011).The countries of the former Yugoslavia are especially rich in numerous epigean and cave-dwelling genera and species.

Study of the Balkan and Montenegrin pseudoscorpion faunas
The first pseudoscorpion species recorded from the territory of the former Yugoslavia was Neobisium spelaeum (Schiødte, 1847) from the Postojna Cave in Slovenia (Schiødte, 1847).
In the 19 th century, further investigations on the Balkan pseudoscorpion fauna were carried out by the French arachnologist Eugène Simon, the English naturalist Edward Ellingsen and the Austrian-Italian entomologist Josef Müller.From 1929 onwards, the Serbian zoologist Jovan Hadţi began important systematic studies on the pseudoscorpion fauna of the Dinaric karst and other parts of the former Yugoslavia and established one new genus, 23 species and five subspecies (Hadţi, 1930a(Hadţi, , b, 1933a, b, c), b, c).An important contribution to study of the Balkan pseudoscorpion fauna was also made by the Austrian arachnologist Max Beier, who established one new genus and listed 55 species and 24 subspecies belonging to the families Chthoniidae and Neobisiidae (Beier,1939).The number of pseudoscorpion species recorded in the countries of the former Yugoslavia is constantly rising.Thus, the number has increased from one species (Schiødte, 1847) to 342 species (Harvey, 2011).Hadţi and Beier can be considered as the initiators of intensive research on this arachnid group in the former Yugoslavia (Dimitrijević, 2000).
The Montenegrin pseudoscorpion fauna is not sufficiently known.The first investigations were conducted in the first half of the 20th century by Beier (1939).The author erected 12 endemic mainly cavernicolous pseudoscorpion taxa inhabiting Montenegro (seven species and five subspecies).In the past 45 years, the main advances toward a better understanding of the pseudoscorpion fauna in Montenegro were achieved by the Serbian arachnologists Boţidar P.M. Ćurĉić and Rajko N. Dimitrijević.After several decades of intensive investigations of the pseudoscorpion fauna, both epigean and cave-dwelling, a monograph entitled "The Pseudoscorpions of Serbia, Montenegro, and the Republic of Macedonia" was published (Ćurĉić et al., 2004b).Boţidar P.M. Ćurĉić greatly contributed to our knowledge of the pseudoscorpion fauna in Montenegro.With his research team, he established 26 species (52% of all known pseudoscorpion species) from Montenegro, as well as all 10 species of the genus Roncus L. Koch, 1873 known from the country.
The purpose of the present study was two-fold: (i) to summarize knowledge about the pseudoscorpion fauna in Montenegro up to now; and (ii) to present a checklist of the taxa (species and subspecies) inhabiting its territory.Records on localities in the country and the world distribution are presented for each pseudoscorpion taxon in Montenegro.

Studied area and material
The studied area is the territory of Montenegro, a country situated in the southwestern part of the Balkan Peninsula.With a population of around 620,000, it covers an area of 13,812 km 2 .Montenegro is a maritime country with 293.5 km of the Adriatic Sea's coastline (Statistical Yearbook MNE, 2015).There are five individual relief units on the territory of Montenegro that differ markedly among themselves: i) the Montenegrin Coast, ii) the plateau of deep karst (the Katun karst, Grahovo region, and the regions of Rudine and Banjani), iii) the Central Montenegrin depression, iv) the region of high mountains and plateaus, and v) the region of Northeast Montenegro (Ćurĉić et al., 2004b).
All available records were collected and cited from the literature concerning the distribution of pseudoscorpions on the territory of Montenegro.The systematics and nomenclature of Ćurĉić et al. (2004b) and Harvey (2011Harvey ( , 2013) ) were used.For review of distributions, we used a map of Montenegro in the Universal Transverse Mercator (UTM) system (grid zone 34T, 100x100 and 10x10 km).

Results and discussion
The pseudoscorpion fauna of Montenegro is represented by 50 species and seven subspecies belonging to eight genera.Compared to all other Balkan countries, Montenegro is in sixth place, after Greece (124), Croatia (106), Romania (72), Serbia (67) and Bulgaria (56).Representatives of six pseudoscorpion families have been recorded in Montenegro.In relation to the total number of recent pseudoscorpion families in the world ( 27), this number represents 22.22% (Harvey, 2011;Ćurĉić et al., 2014b).
The pseudoscorpion fauna of Montengro is characterized by a high degree of endemism.According to current knowledge, 72% of all recorded species (36 out of 50) and 100% of all subspecies inhabiting Montenegro are endemics.
Within the genus Chthonius, nine out of 11 known species in Montenegro are endemics (81.82%).Within the family Neobisiidae, the genus Neobisium includes 17 endemic species and seven endemic subspecies (70.83% and 100%, respectively), while all representatives of the genus Roncus (10 species or 100%) are endemic to Montenegro.
Distribution of species.The pseudoscorpion fauna in Montenegro is unevenly represented in different regions mainly because not all parts of the country have been investigated to the same extent (Fig. 1).Out of the total number of recorded pseudoscorpion taxa in the country, no precise localities are known for 16 species and two subspecies.The western and southern regions of Montenegro are inhabited by the greatest number of pseudoscorpion taxa.The pseudoscorpion distribution for the most part coincides with the distribution of karst relief in Montenegro, since many pseudoscorpion taxa are cavernicolous (29 out of 50 species -58%, and four out of seven subspecies -57.14%).Different forms of the karst relief in Montenegro favoured the differentiation and genesis of cave-dwelling taxa.
The pseudoscorpion fauna in Montenegro has been least investigated in its eastern part, while the western and southern parts have been investigated the most (Fig. 1).Future investigations should include the country's central and eastern parts and cover habitats other than caves and pits.
The complex of endemics (Balkan endemics and endemics of Montenegro) forms the largest group, including 43 taxa (eight species and three subspecies endemic to the Balkans, and 28 species and four subspecies endemic to Montenegro).The majority of endemics were encountered mainly in caves, gorges and high-altitude zones of mountains.The genesis of these taxa and their diversification are connected with the Alpine Orogeny, which led to the formation of an extensive system of cavities, channels, caves and pits capable of offering shelter to this threatened fauna.Such a limited distribution of some cave-dwelling and endogean pseudoscorpion taxa in Montenegro has also been partly dictated by the competitive pressure of other species.Another factor to be considered is influence of the Pleistocene glaciations that encompassed the Balkan Peninsula (Ćurĉić et al., 2004b).
The complex of Europeo-Mediterranean taxa includes seven species, that of widely distributed taxa includes three species, there are two species in the complex of Mediterranean taxa, while the complexes of European and cosmopolitan taxa comprise one species each.

Figure 1 .
Figure 1.UTM map of the current distribution of 25 pseudoscorpion species and 4 subspecies in Montenegro (modified after Ćurĉić et al., 2004b).