Taranucnus beskidicus Hirna 2018, new species
Creators: name: Hirna, Anna
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Linyphiidae
Taranucnus
Taranucnus beskidicus

description: Taranucnus beskidicus new species (Figs 3–19, 21)
Type material. One male holotype and two female paratypes. UKRAINE: L’viv oblast’: Skole district, Skole Beskids National Nature Park, the eastern outskirts of the village of Hrebeniv, 48°58'03''N, 23°27'47''E; 645 m, stony bank of a mountain stream in fir-beech forest, between stones, 23.VI.2015, leg. Hirna (Institute of Ecology of the Сarpathians NAS of Ukraine).
Etymology. The species epithet derived from the name for a series of mountain ranges in the Сarpathians, the Beskids or Beskid Mountains, which stretch from the Сzech Republic in the west and along the border of Poland with Slovakia to Ukraine in the east.
Diagnosis. Taranucnus beskidicus n. sp. is most similar to T. bihari and T. carpaticus according to the conformation of the palp, including the same type of modification of the basal part of cymbium: the complex dorsal apophysis and the long lateral apophysis which begins from the dorsal depression of the cymbium and is an extension of its mesal brim. Males of Taranucnus bescidicus can most easily be distinguished from other Taranucnus species by the apical part (apex) of the dorsal cymbial apophysis, dorsal projection of which looks like a triangular plate with three-lobed edge, not Ushaped and two-lobed like T. bihari and T. carpaticus (Figs 1–3). The apical lobe is the largest, with parallel edges, slightly rounded. In the lateral projection, the apex is also three-lobed, “comb-shaped”. In addition, male specimens of T. beskidus can be differentiated by the elevated head region on the prosoma, a greater distance between posterior median eyes (more than their diameter apart; Figs 4–6, 14), smaller values of the length-width ratio of chelicerae and the number of teeth on the posterior cheliceral furrow margin (Table 1). Females are diagnosed externally by the form of the edge of the anterior wall of epigynal cavity (without “mucrone” sensu Fage 1931, Gnelitsa 2016; Figs 20, 22), which has more sharpened triangular cut, than in other species (Figs 11, 19); internally by the vertically directed and slightly spirally twisted copulatory ducts, that are leading to the spermathecae (Figs 13, 21).
Description. Male (holotype). Total body length 2.63. Сarapace: 1.27 long, 1.08 wide; dorsally yellow, laterally darker (yellow-brown with grey), with a narrow grey margin. Elevated head region, brown-yellow with rows of macrosetae, converging from posterior eyes to fovea (longest scattered between posterior medial eyes); anterior lateral eyes are the largest; all eyes black bordered; distance between posterior median eyes ≈ 2 diameters (Figs 4–6, 14). Sternum: 0.67 long, 0.59 wide, covered with long thin erect setae (hairs), suffused with brown, and extended between coxae IV. Labium is gray, maxilla yellow-brown. Сhelicerae: 0.75, yellow, with stridulating files; anterior cheliceral furrow margin with three large teeth, posterior margin with five small ones; anterior side of the chelicerae with macrosetae. Abdomen is ventrally dark grey and dorsally pale grey with a black pattern. Legs yellow; FeI—1d: 1pl; FeII—1d; FeIII—1d; TiI—2d: 1pl: 1rl: 2v; TiII—2d: 1rl: 1v; TiIII– IV—2 d; MtI– IV—1 d; the position of metatarsal trichobothrium (I–III): 0.18–0.19 (Table 1). Pedipalpal patella short, bearing a long and bent dorsal spine. Tibia unmodified, with numerous macrosetae. Retrobasal region of cymbium with broad and curved dorsally apophysis, its apex with three-lobed edge and covered with macrosetae. Long lateral (mesal) apophysis as an extension of mesal cymbial brim; with long macrosetae. Dorsal surface of the lateral apophysis extending in an insignificant sclerotized ledge, which ends as a denticle, not reaching the distal sharpened tip of the apophysis (Fig. 3). Paracymbium U-shaped: proximal part thickened, with bifurcate tip bearing macrosetae; distal tip widened into a flat rounded and strongly sclerotized plate. Subtegulum elongated, with apophysis frontally. A large and flat embolic membrane gradually twisted in the loop, arising between median apophysis and radix, and ending next to the apical part of cymbium. Embolus no longer than embolic membrane, gradually tapering to a thread-like tip. Radix with two apophyses of complex configuration: anterior (first) apophysis hook-like, second apophysis with median and mesal teeth (on the frontal view). Distal suprategular apophysis relatively long and wide (Figs 7–9, 15–17).
Female (paratype). Total length 2.92. Сarapace: 1.2 long, 1.10 wide; dorsally yellow, laterally darker (yellow-brown with grey); with narrow grey margin; all eyes black bordered; posterior median eyes a diameter apart, only anterior median eyes slightly smaller than others. Sternum: 0.74 long, 0.66 wide, covered with long thin erect setae (hairs), suffused with brown, and extended between coxae IV. Labium gray, maxilla yellow-brown. Сhelicerae: 0.64, yellow, with thin stridulating files; anterior cheliceral furrow margin with three large, and posterior with five tiny teeth; anterior side of chelicerae with macrosetae. Abdomen ventrally dark grey, dorsally pale grey with black pattern (Fig. 18). Legs yellow; FeI—1d:1pl; FeII—1d; FeIII—1d; TiI—2d: 1pl: 1rl: 1v; TiII—2d: 1rl: 1v; TiIII– IV—2 d; MtI– IV—1 d; position of metatarsal trichobothrium (I–III): 0.16–0.18 (Table 2). Epigynum is wide and protruding. Edge of the anterior wall of epigynal cavity with triangular cut (Figs 10–11, 19). Сopulatory ducts long, form the loops; transparent and almost invisible. Well visualized only thin, slightly spirally twisted copulatory ducts leading to the massive spermathecae (Figs 13, 21). Fertilization ducts short, anteriorly orientated (Fig. 12).
Variation: female carapace length varies from 1.26–1.28; female total body length ranges from 2.87 to 2.92 (n = 2). Habitat. Un-vegetated deposit beds of mountain streams in fir-beech forest, formed of gravels, boulders and finer sediments bordering the shores of the stream and forming stream islands.
Comments. The three European species (Taranucnus bihari, Taranucnus carpaticus, and Taranucnus beskidicus n.sp.), could be combined into the bihari species group based on the structure of epigynum and male palp, including the type of modification of the basal part of the cymbium. To obtain a reliable map of the distribution of this species-group within Eastern Europe, it is necessary to conduct a revision of the material collected on the territory of individual countries; in particular, Poland, Romania and Slovakia, taking into account the morphological differences between Taranucnus bihari and Taranucnus carpaticus. In this paper, localities of species are given only for the territory of Ukraine (Fig. 23). The information about new records serves as a supplement to the data presented in the publication of Gnelitsa (2016).
description: Published as part of Hirna, Anna, 2018, A new species and new records of the spider genus Taranucnus (Araneae, Linyphiidae) from the Ukrainian Carpathians, pp. 372-378 in Zootaxa 4429 (2) on pages 372-377, DOI: 10.11646/zootaxa.4429.2.11, http://zenodo.org/record/1283931