Vertagopus asiaticus

Description. 8 + 8 ommatidia of which G and H much smaller (Fig. 9). PAO elliptical, about twice as long as nearest ommatidium and shorter (0.6 – 0.7) than Ant. I width. Maxillary outer lobe with 4 sublobal hairs and bifurcate palp. Labrum with 4 prelabral chaetae, labral edge with four sharp ridges. Labial palp with all usual papillae and 15 guards (e 7 absent), 4 proximal, 4 basomedian and 5 basolateral chaetae. Ventral side of head with 4 – 5 + 4 – 5 postlabial chaetae. Maxillary head with unmodified lamellae. Ant. I with 2 ventral bms at base and 4 – 5 ventral s of which 1 – 2 short in distal row (Fig. 9). Ant. III with several sens, one of which in lateral position thick. Ant. IV with bifurcate subapical pin-chaeta and very small peg-like organite. Body with almost smooth, sometimes indistinctly serrated, macrochaetae. Macrochaetae on Abd. V longer than this segment length (1.05 – 1.35, Fig. 21). Number of macrosens in full grown specimens as 4,4 / 3,3,3,4,6 (Figs 19, 21). Th. II – III with 2 accp - sens and 2 al - sens. On all segments accp - sens in p - row. On Abd. V six sens arranges as two in anterior position and four in p - row. Microsens 1,0 / 0,0,1 in number, on Abd. III ms associated with p - row. First instar has principally the same sensillar chaetotaxy (Fig. 20). Th. III without ventral chaetae, Abd. II without ventromedial group of chaetae. Legs with claws of normal shape, with two lateral and one inner tooth. Empodium with minute inner tooth. Tibiotarsi with 9 chaetae in distal whorl, T 2 and T 3 chaetae absent, T 1 and T 4 present (Figs 12, 13). Clavate tenent hairs present, usually 1 (2), 2,2 in number: A 1 on tibiotarsus 1, A 1 and A 7 on tibiotarsus 2, and A 1 and A 2 on tibiotarsus 3. Tenent hairs on tibiotarsi 2 and 3 clearly different in size, A 1 always being longer and more distinctly clavated. Length of A 1 about as long as inner edge of claw (0.8 – 1.2). Retinaculum with 4 + 4 teeth and 6 – 9 chaetae. Ventral tube (Fig. 10) with 4 + 4 (5 + 5) laterodistal, without anterior and with 5 posterior chaetae (4 in distal transversal row and one at base). Furca rather long, 1.05 – 1.30 times longer than length of antennae. Manubrium with 21 – 26 chaetae on anterior side (Fig. 14), with " single " row of chaetae on lateral sides (Fig. 11). Manubrial thickening simple. Dens continuously narrowed, crenulated, with 8 chaetae on posterior side (4 basal and 2 + 2 di- de), rarely 3 on one side in middle group (Fig. 15). Anterior side of dens strongly chitinized, with more than 50 chaetae (up to 70 in large individuals). Mucro with four teeth, " apical " tooth very small (Figs 16, 17). Ratio dens: manubrium as 1.8 – 2.2. Body size up to 1.6 mm. Regularly bluish, sometimes dark (Fig. 27).

Discussion. The species is characterized by the absence of two T - chaetae (T 2 and T 3) on tibiotarsi, a character unknown for the genus. Due to this peculiarity V. asiaticus sp. nov. is somewhat in an intermediated position between genera Vertagopus (all T - chaetae present) and Pseudisotoma (T 2, T 3, T 4 absent). Due to the shape of the mucro and independence of two last abdominal segments V. asiaticus sp. nov. is classified by us with Vertagopus while further study is needed. Another peculiarity of the new species is few posterior chaetae in di-de group combined with long and dorsally polychaetotic dens. After sensillar pattern V. asiaticus sp. nov. formally belongs to ' westerlundi ' group. Another closely related new species was collected by us in Western Caucasus, which also has no T 2 and T 3 chaetae but differs by more sens on body tergites. One species from NE China, V. arborata Fusheng, Huifen & Yueling, also has 1,2,2, clavate tenent hairs and differs by large apical tooth on mucro, two inner teeth on claw, and presence of either T 2 or T 3 on tibiotarsi. The last character is evident from the figure given in first description of V. arborata.

Distribution and ecology. V. asiaticus sp. nov. is distributed widely in the Asiatic part of Russia, but no records exist for the Arctic (Fig. 29). Literature records of V. arboreus in Asia (Uchida 1969, Martynova 1979) may refer to this species. The species lives under loose bark of dead trees and in rotten wood where it can occur together with V. pseudocinereus. Unlike the latter, V. asiaticus sp. nov. also often inhabits forest litter and organically enriched sites.

Etymology. The name reflects wide geographical distribution in Asia.

Type material. Holotype, NW Buryat Republic, at northern shore of Baikal Lake, ca. 25 km west from Severobaikal'sk, Goudjekit, 55.71031 ° N, 109.03793 ° E, larch forest, ca. 600 m. alt., rotten wood, 20. viii. 2013, coll. A. Gulgenova and M. Potapov (MSPU). Paratypes, 10 specimens on slides and 10 specimens in alcohol, ibidem (MSPU and BSU). Other material. Buryat Republic: NW Buryatia, Barguzinsky Range, ca. 10 km W Barguzin, upper flow of Gremyachaya Brook, ca. 1400 m alt., subalpine belt, mosses and lichens on wind erosion areas, 20. viii. 2008, coll. M. P. and A. G.; N Buryat Republic, Dzergynsky Nature Reserve, upper flow of Barguzin River, at " 81 km " Station, 1076 m alt., 55.34881 ° N, 111.49967 ° E, larch wood in river valley, in rotten wood, under bark of larch tree and in litter, 10 – 12. ix. 2012, coll. A. G. and M. P.; NW Buryat Republic, northern shore of Baikal Lake, Goudjekit, larch forest, ca. 600 m. alt., rotten wood, 20. viii. 2013, coll. A. G. and M. P.; Ibidem, lake nearby Goudjekit, ca. 700 m alt., Sphagnum at water edge, 16. viii. 2013, coll. A. G. and M. P.; Ibidem, Akulikan Stream, ca. 700 m alt., mosses on river bank, 15. viii. 2013, coll. M. P. and A. G.; Ibidem, mosses at bank of Goudjekit River, 15. viii. 2013, coll. M. P. and A. G.; S Buryat Republic, at Zagansky Range, Arshan, SE slope, 985 m alt., 50.81451 ° N, 107.78026 ° E, larchbirch forest, under bark, 20. viii. 2011, coll. A. G. & L. V.; E Buryat Republic, Eravninsky District, nearby Telemba, larch forest, rotten wood and under looser bark, 15. viii. 2008, coll. M. P.; S Buryat Republic, Dzidinsky District, nearby Borgoi, grass meadow in depression, soil; ibidem, under bark of dead larch tree. 1. viii. 2014, coll. M. P. Russia: Irkutskaya Region: W Khamar-Daban Range, Slyudyanka River, taiga belt, under looser bark of poplar-tree, 25. viii. 2008, coll. M. P.; Irkutsk, botanic garden, under bark, 01. ix. 2008, coll. V. Kadnikov. Russia: Ural: Middle Ural Mts., Sverdlovskaya Region, nearby Revda, impact zone of copper pollution, under bark of dead poplar trees, 29. vii. 2002, coll. M. P.; Sverdlovskaya Region, flow of Serga River, nearby Katnikova Cave, floodplain, on fallen trunk, 03. viii. 2002, coll. M. P. Russia: East Siberia: Zabaikal'sky Krai: Alkhanai National Park, valley of Ilya River, nearby Ara-Ilya Station, ca. 880 m alt., 50.925133 ° N, 113.173417 ° E and 50.930433 ° N, 113.213783 ° E, litter of birch forest with larch, litter of pine forest, mosses at bank of Ilya River, 7 – 12. vii. 2014, coll. A. G. Russia: East Siberia: Yakutia: Suntar-Khayata Range, upper flow of Kyubyume River, " Vostochnaya " meteorological station, greenhouse, 23. vii. 2002, coll. O. Makarova. Russia: Far East: Primorsky Krai: South Primorye, Shkotovsky area, valley near Vorobey Mt., under bark, 11. ix. 2011, coll. M. P.; Shkotovsky area, Anisimovka, under bark of dead poplar tree and tree stump, 20. ix. 2004, coll. M. P.; Shkotovsky area, Livadiysky Range, Khualaza Mountain, under bark of logs, 18 – 19. ix. 2004, coll. M. P.; Primorye, Lazovsky area, in mountains nearby Preobrazheniye, ca. 500 m alt., grass turf in coniferous forest, 21. ix. 2011, coll. M. P.; South Primorye, Khasansky area, near Barabash, valley forest, litter and under bark of dead tree, 27. ix. 2004, coll. M. P.; South Primorye, Khasansky area, Kedrovaya Pad' Nature Reserve, forest litter, 2. x. 2009, coll. O. Smirnova; Ussuriysky area, Ussuriysky Reserve, near water edge of Kamenushka River (sedge turf), 05. x. 2004, coll. M. P.; middle flow of Bikin River, nearby mouth of Amba River, 46.69949 ° N 135.77142 ° E, under maple tree, 20. ix. 2009, coll. O. Smirnova; Kirovsky district, Gornye Klyuchi (Shmakovka), mixed forest, coll. E. Sokolova. Russia: Far East: Kamchatka: Surroundings of Petropavlovsk-Kamchatsky, Elizovo, on tree stump in garden, 2004, coll. L. Lobkova; Kamchatka, Bystrinsky area, Anavgai village, ca. 450 m alt., 56.06059 ° N, 158.93608 ° E, floodplain of Bystraya River, under bark of dead tree, 3. vii. 2012, coll. M. P.; ibidem, mouth of Razdelny Stream, 494 m alt., mixed taiga, from pitfall-traps, 3 – 5. vii. 2012, coll. M. P. Russia: Far East: Khabarovsky Krai: Bureinsky Nature Reserve, middle flow of Pravaya Bureya, Medvezye Station, ca. 950 m alt., ~ 52.15 ° N, ~ 134.316667 ° E, larch and willow litter, 16. vii. 2005. coll. I. Lyubechansky; Middle flow of Amur River, ca. 25 km S Khabarovsk, Khekhtsyr Range, near Korfovsky, coniferous and mixed forests, litter, in rotten wood, under looser bark, 24 – 25. iv. 2010, coll. E. Sokolova and M. P.; Ibidem, Khekhtsyr Range, mixed forest (Pinus sibirica), 17. ix. 1988, coll. V. Behan; Ibidem, 10 km N Korfovsky, mixed forest, 24. ii. 2007, coll. E. Sokolova; Low flow of Amgun' River (not far from Nikolaevsk-na-Amure), forest with poplar and birch, 01. vii. 1990; Ca. 100 km N Komsomol'sk-na-Amure, Evoron Lake, silver fir forest, 03. viii. 1988, coll. N. Ryabinin; Suburbs of Khabarovsk, Voronez highlands, gorge of spring, mosses on stones sprinkled with water, 26. iv. 2010, coll. M. P.; Verknebureyskoye Reservoir, Nizniy Mel'gin Bay, mixed forest on southern slope (Larix, Betula, Abies), 12. ix. 2009, coll. M. Babykina. Russia: Far East: Amurskaya Region: Zeysky Reserve, 52 km of road Zeya – Beregovoy, ca. 300 m alt., " 52 km " Station, valley of Erakingra River and open larch forest on northern slope, under bark of fallen branch, 21 – 22. viii. 2014, coll. M. P. and N. K.; ca. 3 km N Zeya City, oak wood on southern slope, under bark, 22. viii. 2014, coll. M. P. and N. K.; nearby Antonovka (ca. 15 km NW Arkhara), under willow, 22. v. 2008, coll. M. Babykina; Arkhara, under bark of dead willow, 17. viii. 2014, coll. M. P. and N. K.; Ca. 3 km W Arkhara, northern slope, oak forest, under bark. 17. viii. 2014, coll. M. P. and N. K.; Khingansky Reserve, ca. 15 km SE Uril, oak forest, 08. x. 2009, M. Babykina; Khingansky Reserve, ca. 10 km E Uril, coniferous forest on northern slope, 07. x. 2009, M. Babykina; Khingansky Reserve, near (3 km W) Kundur, valley of Karapcha River, southern slope, dry oak forest, under bark. 19. viii. 2014, coll. M. P. and N. K. Russia: Far East: South Kuril Isls: Kunashir Isl., caldera of Golovnina Vulcano, Goryachee Lake, debris on lake shore, 24. viii. 2008, coll. K. Makarov. China. Heilongjiang Province (NW China), Small Hinggan Range, ca. 50 km W Heihe, rotten wood in mixed forest, and litter in wet grassy birch-forest, 15. viii. 2014, coll. M. P., C. - W. Huang, Y. Luan; Inner Mongolia Province, Da Hinngan Ling Mts, ca. 5 km NW BaLin, floodplain forest, under loose bark, Ibidem, ca. 3 km SE BaLin, floodplain pasture, in bushes, under loose bark, 12. viii. 2014, coll. M. P., C. - W. Huang, Y. Luan; NE China, Jilin Province, nearby Changchun, Changchun-Jingyue Lake, mixed forest, under bark of willow, 20. IV. 2010, coll. M. P. and D. Wu.