Pholeuonopsis ( Pholeuonopsis ) perucensis sp . n . , a new troglobitic leiodid beetle ( Coleoptera : Leiodidae : Cholevinae : Leptodirini ) from Bosnia and Herzegovina

A new leptodirine beetle species, Pholeuonopsis (Pholeuonopsis) perucensis sp. n., from a cave in Eastern Bosnia and Herzegovina is both described and diagnosed. The structure of both male and female genitalia and other taxonomically important characters are imaged. The new beetle species is clearly distinct from all other congeners. It probably belongs to an old phyletic lineage of Tertiary origin, like other known Pholeuonopsis taxa from the Western Balkan Peninsula. The new species is both an endemic and a relict inhabiting solely Eastern Bosnia and Herzegovina.

The Pholeuonopsis taxa have a pholeuonid and elliptic external morphology, are of medium-size and found both in underground habitats (caves and pits) and soil (endogean forms) (Jeannel 1924).

Material and Methods
The type specimens were captured by hand from a wall in the posterior, totally dark part of the Peruc Cave near Foča, Eastern Bosnia and Herzegovina (GPS coordinates 43°31'57.00"N 18°36'27.90"E).
The specimens were studied in the laboratory of the Institute of Zoology, University of Belgrade -Faculty of Biology, Belgrade, Serbia.The beetles were dissected, thoroughly analyzed, and photographed.Dry specimens were stuck onto rectangular paper labels.Both male and female genitalia were fixed in a medium composed of Canada balsam and xylol.
All taxonomically important morphological characters were studied for the comparison with related taxa.Carl Zeiss -Stemi 2000 and Carl Zeiss Discovery V8 binocular stereomicroscopes with a Canon G10 digital camera, as well as Nikon Eclipse E100 microscope with a Moticam 2000 digital camera attached were used in the study.Diagnosis.-The new species clearly differs from all other existing Pholeuonopsis taxa from Bosnia and Herzegovina, Serbia and Montenegro.The phenetically closest species are Pholeuonopsis (Pholeuonopsis) setipennis Apfelbeck, 1907, P. (P.) intermedius and P. (P.) grabowskii Apfelbeck, 1907, all inhabiting Bosnia and Herzegovina.There are numerous distinctions between the new species and the mentioned three species, and these are presented below.Thus, Pholeuonopsis (Pholeuonopsis) perucensis sp.n. clearly differs from P. (P.) setipennis in the total body length (minimum-maximum values 3.44-3.73mm vs. 4.00-4.20 mm), the maximum width of the pronotum (at the posterior pronotal angles vs. at the posterior pronotal angles/at the mid-length), the form of the posterior pronotal angles (acute vs. almost right/more acute), the shape of the angle of the mesosternal carina (obtuse, with a tooth vs. hook-like), the form of the anterior edge of the mesosternal carina (very convex vs. very convex/straight), the form and length of the median lobe (more stout, thicker in the apical half, with an acute apex, slightly longer than parameres vs. more elongate, sub-parallel, with a rounded apex, as long as parameres), the shape of both the basal bulb (longer, with a long curved median process vs. shorter, with a short rounded median process) and parameres (curved exteriorwards vs. almost straight), the distribution and shape of the parameral setae (close-set, the apical and the upper inner one being somewhat closer than the two inner setae, apical seta curved vs. somewhat separated mutually, all setae equidistant, apical seta straight), and the shape of the copulatory piece (basal phanera shorter and thicker, two basal sclerotized short straight structures present vs. basal phanera longer and narrower, two basal sclerotized short straight structures absent) (Apfelbeck 1907b;Jeannel 1924;Zariquiey 1927; present study) (Figs.2-4 and 6).

Systematics
Pholeuonopsis (Pholeuonopsis) perucensis sp.n. clearly differs from P. (P.) intermedius in the total body length (minimum-maximum values 3.44-3.73mm vs. 4.60 mm) and shape (less elongate vs. more elongate), the form (thicker vs. narrower) and length of the antennae (slightly exceeding the middle of the elytra in males and ending slightly before the middle of the elytra in females vs. slightly exceeding the middle of the elytra in both sexes), the antennomere II/I length ratio (1.29 vs. 1.33), the form and length/width ratio of the antennomere VIII (globulose, slightly longer than wide vs. cylindrical, twice as long as wide), the form of the lateral pronotal margins (regularly rounded vs. obtusely rounded), the shape of the posterior pronotal angles (acute, not rounded vs. almost right, somewhat rounded), the elytra/pronotum length ratio (2.35 vs. 2.75), the maximum width of the elytra (somewhat anterior to the mid level vs. anterior to the first third), and the shape of the elytral margins (weakly arcuated vs. more rounded) (Knirsch 1929; present study) (Fig. 2).Finally, Pholeuonopsis (Pholeuonopsis) perucensis sp.n. clearly differs from P. (P.) grabowskii in the total body length (minimum-maximum values 3.44-3.73mm vs. 4.00-4.50mm), the size of the pronotum (small vs. large), the form of the lateral pronotal margins (inconspicuously constricted basally vs. profoundly constricted basally), the maximum width of the pronotum (at the posterior angles vs. at the posterior angles/around the middle), the form of the posterior pronotal angles (acute vs. acute/right), the shape of the elytra (inversely ovate vs. oval), the maximum width of the elytra (somewhat anterior to the mid level vs. in the middle), the length/width ratio of the elytra (1.34 vs. hardly 1.50), and the distribution of long erect setae on the elytra (mostly in the posterior part vs. mostly laterally, nearly missing in the posterior part) (Apfelbeck 1907a;Breit 1913;Knirsch 1928;Jeannel 1930; present study) (Fig. 2).
Head slightly longer than wide, narrower and shorter than pronotum.With sparsely distributed short erect hairs.Occipital carina inconspicuous.Without eyes.Covered with both fine puncturation and a few impressions on the frons.Mouthparts pubescent, specialized for filtering organic matter from trickling water from cave walls (Moldovan et al. 2004).Genae somewhat concave.Antennae elongate, slender, somewhat widened distally, pubescent, more elongate in males, slightly exceeding the middle of the elytra in males and ending slightly before the middle of the elytra in females.Combined pronotum and elytra length to antenna length ratio: 1.35 (males) and 1.47 (females).Antennae inserted at around the mid-head level.All antennomeres longer than wide.Antennomere I somewhat widened, with a small basal globulose appendix, around as long as antennomere III.Antennomere II narrow, 1.29 times as long as antennomere I.
Antennomere II longer than antennomere III.Antennomere VIII the shortest, globulose, slightly longer than wide.Antennomeres II-VI moderately thickening apically, while antennomeres VII and IX-XI well broadened.Distalmost antennomere ovoid, slightly longer than the penultimate one.
Pronotum small, sub-bell-shaped, wider than long (length/width ratio in both sexes 0.66), widest at the posterior angles, covered with dense, short, yellowish laid setae and impressed punctures (Fig. 2).The lateral margins bordered, inconspicuously sigmoidly shaped, somewhat rounded anteriorly.Posterior pronotal margin shorter than the base of elytra.Both anterior and posterior pronotal margins somewhat convex medially.Anterior pronotal angles rounded, obtuse, and the posterior ones acute, pointed, prominent, somewhat protruding backwards.Pronotal disc weakly convex, with two basal shallow impressions.Mesosternal carina high, sub-triangular, obtuse, carrying a tooth distally and a few teeth and a number of setae on the posterior edge (Fig. 3).The anterior edge very convex, while the posterior one somewhat concave.Metasternum without carina.Elytra elongate, inversely ovate (length/width ratio 1.34), somewhat wider than pronotum, wider in females than in males (female/male elytral width ratio 1.04) (Fig. 2).Elytra/pronotum length ratio 2.35.The maximum width reached somewhat anterior to the mid level in both sexes.The lateral margins wellchitinized, sub-parallel anteriorly, but rounded posteriorly.Marginal furrows relatively wide, shallow, gradually narrowing towards elytral apex.Shoulders obtuse, rounded.Elytral disc convex, gradually declining anteriorly, but steeply declining posteriorly, with numerous short, yellowish laid setae on the whole surface, and less numerous very long yellowish erect setae situated mostly in the posterior part.Elytral punctures densely distributed and deep.Scutellum large, triangular.Elytral apex rounded.
Legs long, slender, with the femora thickened basally (Fig. 2).Tibiae somewhat curved, moderately thickening apically.Meso-and metatibiae with a few fine spines each.Protarsi 4-segmented and narrow in both sexes.The first protarsomere slightly less than three times as long as wide, somewhat shorter than the following two protarsomeres combined.Tarsal claws long, thin, sharply pointed.
Female abdominal segment VIII large, transverse, with a short wide anterior process, possessing both short and long setae distally (Fig. 10).
Figure 11.The plan of the Peruc Cave, village of Izbišno, near Foča, Eastern Bosnia and Herzegovina (modified after Dujaković, 2004).The red circle represents the place where the specimens of the new species were found.
Bionomy and distribution.-The new species was found on a wall in the posterior, totally dark part of the Peruc Cave (Fig. 11).The species prefers wet clay cave walls, where it probably feeds on filtrated organic matter from trickling water.The additional leiodid taxa found in the cave were Leptinus testaceus Müller, 1817 and Catops sp.The Peruc Cave is also inhabited by a rich fauna of other arthropods (isopods, millipedes and spiders).
Like the other Pholeuonopsis taxa, the new species probably belongs to an old phyletic lineage of Tertiary origin (Guéorguiev 1977;Ćurčić and Brajković 2002;Ćurčić et al. 2006).Pholeuonopsis (Pholeuonopsis) perucensis sp.n. is endemic to the Dinarides in Eastern Bosnia and Herzegovina and represents a relict form (Guéorguiev 1977;Ćurčić and Brajković 2002;Ćurčić et al. 2006).The following phenomena facilitated the endemic differentiation of Pholeuonopsis taxa on the Balkan Peninsula: the Alpine Orogeny, paleoclimatic events and subsequent evolution of the underground karstic relief (Guéorguiev 1977;Ćurčić 1988).These enabled the creation of numerous new endogean and underground niches suitable for the preservation of the old and autochthonous fauna (Ćurčić 1988).
A field trip organized by Mr. Dragan Antić (Institute of Zoology, University of Belgrade -Faculty of Biology, Belgrade, Serbia) in Eastern Bosnia and Herzegovina resulted in the discovery of a new Pholeuonopsis species: P. (P.) perucensis sp.n.The description and diagnosis are given in the present paper.The diagnosis of P. (P.) perucensis sp.n. is based on a thorough analysis of the type series of three males and four females collected during 2014 in the Peruc Cave near Foča, Eastern Bosnia and Herzegovina.