Zootaxa 4088 (1): 112–128 ISSN 1175-5326 (print edition) http://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2016 Magnolia Press ISSN 1175-5334 (online edition) http://doi.org/10.11646/zootaxa.4088.1.5 http://zoobank.org/urn:lsid:zoobank.org:pub:C1EA3A19-D65F-4E39-97D3-0311A85A4816 Isotomidae (Collembola) of Buryat Republic. III. The genera Vertagopus and Agrenia, with a note on 'Claw index' MIKHAIL POTAPOV1 , AYUNA GULGENOVA2 & MARINA BABYKINA3 1Moscow Pedagogical State University, Moscow 129164, Kibalchicha St. 6 b. 5, Russia. E-mail: [email protected] 2Buryat State University, Ulan-Ude 670000, Smolina St. 24a, Russia. E-mail: [email protected] 3Khingansky State Nature Reserve, Arkhara 676740, Dorozhnyi St. 6, Russia. E-mail: [email protected] Abstract Two genera are revised based on material from Buryatia (Russia, East Siberia). Vertagopus ceratus sp. nov. and V. asiat- icus sp. nov. are described of which the former species is strictly alpine and is defined by pale colouration, the presence of chaetae on the anterior side of the ventral tube, and abundant sensillar chaetotaxy. V. asiaticus sp. nov. is widely dis- tributed in Asia and is unusual due to only 9 chaetae in apical whorl on tibiotarsi. A key to species of Vertagopus Börner, recorded in the republic is given, and notes on morphology, distribution, and ecology are provided. In the genus Agrenia Börner, a form similar with A. bidenticulata was recorded in mountainous areas. Buryatian populations considerably differ from the diagnosis of the typical arctic A.bidenticulata (Tullberg) by a much longer claw. A conception of A. bidenticulata sensu lato complex is temporarily proposed basing on available materials from Palearctic, including High Arctic, sub-Arc- tic and South Siberian mountains. The complex consists of several local forms which are different in Claw index and as- sociated Tibiotarsus/Claw ratio, while the dependence of the two indexes on the latitude is shown. Key words: distribution area of species, Baikal, Buryatia, new species, springtails Introduction This paper is our fourth special contribution to taxonomy of Isotomidae of Buryatia (Potapov & Chimitova 2009, Chimitova & Potapov 2011, Potapov & Gulgenova 2013). During the progress of our sampling of Siberian Collembola we paid considerable attention to such microhabitats as decaying wood, looser bark of dead trees, and aquatic sites that made it possible to collect the representative collection of two genera of subfamily Isotominae: Vertagopus Börner and Agrenia Börner. In this work we make the revision of these two genera of the Buryat Republic. An annotated list of seven species of the genera, including new, is given. Many new records from the areas adjacent to Buryatia are also cited for the new species. Material and methods The types are deposited in the collection of the Department of Zoology & Ecology of MSPU (Moscow, Russia) and Department of Zoology of BSU (Ulan-Ude, Russia). Abbreviations: alt.—altitude; A1, A2, A7—chaetae of apical whorl in tibiotarsi; Abd.I–VI—abdominal segments I–VI; accp—accessory p-row s-chaeta; Ant.I–IV—antennal segments I–IV; as—anterosubmedial s- chaeta; bms—basal micro s-chaeta on antennal segments; BSU—Buryat State University; ca.—approximately; di, de—dorso-internal and dorso-external chaetae of dens; e7—guard of labial papilla E; Leg I,II,III—first, second and third pairs of legs; M—macrochaeta; microsens in the text or ms in the text and figures—micro s-chaeta(e) (=microsensillum(a) auct.); macrosens or sens in the text or s in the text and figures—macro s-chaeta or s-chaetae (=macrosensillum(a) or sensillum(a) auct.); MSPU—Moscow State Pedagogical University; PAO—postantennal organ; T1–T4—additional chaetae of apical whorl in tibiotarsi; Th.II–III—thoracic segments II and III; tun— tunica. 112 Accepted by W.M. Weiner: 18 Dec. 2015; published: 8 Mar. 2016 Collectors: A.G.—Ayuna Gulgenova, A.B.—Anatoly Babenko, L.V.—Lilya Vanyavina, M.P.—Mikhail Potapov, N.K.—Natalia Kuznetsova, V.B.—Valery Bulavintsev. Results List of Buryatian Vertagopus and Agrenia species Genus Vertagopus V. ceratus sp. nov. V. asiaticus sp. nov. V. laricis Martynova, 1975 V. pseudocinereus Fjellberg, 1975 V. westerlundi (Reuter, 1898) Genus Agrenia A. bidenticulata (Tullberg, 1876) s.l. A. riparia Fjellberg, 1986 Genus Vertagopus Börner In the conception of European Isotominae the genus is well defined with the presence of clavate tenent hairs on tibiotarsi, a full set of chaetae in apical tibiotarsal whorl (11), and two last abdominal segments separated. Two species of Buryatia show an incomplete set of the key characters mentioned above: V. asiaticus sp. nov. lost two T- chaetae in apical whorl (deficient set) while V. larici s has two last abdominal segments fused. Thus, Asiatic species make the status of the genus more questionable although the value of differentiating characters of Vertagopus were already doubted long before (Fjellberg 1978). The local species of the species can be classified by the ecology into two groups: xylophilic species related with rotten wood (asiaticus sp. nov., pseudocinereus) and xerophilic species inhabiting dry litter, mosses and lichens (ceratus sp. nov., laricis, westerlundi). Vertagopus ceratus sp. nov. Figs 1–8, 18, 22, 25, 26 Type material. Holotype, Russia (East Siberia): N Buryat Republic, Dzergynsky Nature Reserve, upper flow of Barguzin River, Balan-Tamur Range, ca. 1800 m alt., 55.36698°N, 111.55280°E, moss-lichen tundra, 09.ix.2012, coll. A.Gulgenova and M.Potapov (MSPU). Twenty paratypes, 10 specimens on slides and 10 specimens in alcohol, ibidem (MSPU and BSU). Other material. Russia (East Siberia): N Buryat Republic, Dzergynsky Nature Reserve, upper flow of Barguzin River, Balan-Tamur Range, ca. 1800 m alt., 55.36698°N, 111.55280°E, mossy sites, litter under Pinus pumila, dry stony slope with lichens and Empetrum, 09.ix.2012, coll. A.G. and M.P.; NW Buryat Republic, northern shore of Baikal Lake, peak nearby Goudjekit, subalpine belt with Pinus pumila, ca. 1600 m. alt., thick lichen spots, 15.viii.2013, coll. A.G. and M.P.; NW Buryat Republic, Barguzinsky Range, ca. 10 km W Barguzin, upper flow of Bol'shoi Chevyrkuy Stream, alpine belt, ca. 1970 m. alt., cold mosses in shadow between rocks, 19.viii.2008, coll. A.G. and M.P. Description. 8+8 ommatidia of which G and H much smaller and hardly visible (Fig. 1). PAO elliptical, about twice as long as nearest ommatidium (1.9–2.5). Maxillary outer lobe with 4 sublobal hairs and bifurcate palp. Labrum with 4 prelabral chaetae and about 6–7 on front, labral edge with four sharp ridges. Labial palp with all usual papillae and complete set (16) of guards (e7 present), 4 proximal, 4 basomedian and 5 basolateral chaetae. Ventral side of head with 4–6+4–6 postlabial chaetae. Maxillary head with unmodified lamellae. Ant.I with 2 ISOTOMIDAE OF BURYAT REPUBLIC Zootaxa 4088 (1) © 2016 Magnolia Press · 113 ventral microsens at base and 5–7 ventral sens of which 2–4 short in distal row (Fig. 1). Ant.II with about ten sens. Ant.IV with bifurcate subapical pin-chaeta and big globular organite. FIGURES 1–8. Vertagopus ceratus sp. nov.: 1, anterior part of head; 2, ventral tube, front view; 3, manubrium, lateral view; 4–5, distal part of tibiotarsus 3 (4) and 2 (5); 6, furca, anterior view; 7, dens, lateral view; 8, distal part of furca. di, de—dorso- internal and dorso-external chaetae, l.ch.—lateral chaetae of manubrium. Body with differentiated smooth macrochaetae. Macrochaetae on Abd.V about as long as this segment length (0.9–1.1). Number of macrosens in full grown specimens as 4–5,4–5/4(3–5),6(5–7),6(5–7),7(6–8),6 (Figs 18, 22). Th.II–III with 2–3 accp and 2 al. On all segments accp in p-row, sometimes one or two moved forward. On Abd.V six sens arranged 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. Th.III without ventral chaetae, Abd.II without ventromedial group of chaetae. Legs with claws of normal shape, with lateral teeth and minute inner tooth. Empodium with indistinct corner inner tooth. Tibiotarsi with 11 chaetae in distal whorl, all T-chaetae present (Figs 4, 5). 2,3,3 clavate tenent hairs of 114 · Zootaxa 4088 (1) © 2016 Magnolia Press POTAPOV ET AL. medium size, about as long as inner edge of claw (0.8–1.0). Retinaculum with 4+4 teeth and 5–7 chaetae. Chaetotaxy of ventral tube (Fig. 2) invariably with 4+4 laterodistal, 1+1 anterior and 3 posterior chaetae (2 in distal transversal row and one at base). Furca rather long, 1.2–1.4 times longer than length of antennae. Manubrium densely covered by chaetae, with more than 40 on anterior side (Fig. 6). With "double" row of chaetae on lateral sides (l.ch. in Fig. 3). Manubrial thickening simple. Dens gradually narrowed towards apex, crenulated (Fig. 7), with 10–12 chaetae on posterior side (4–6 basal and 3+3 di-de). Anterior side of dens with more than 70 chaetae. Mucro with four teeth as common for the genus, "apical" tooth small (Fig. 8). Ratio dens : manubrium as 1.8–2.1. Body size 1.1–1.3 mm. Pale, often totally yellowish-white (Figs 26), with dark pigment on ommatidia, at antennal bases and front of head; distal half of antennae darker. Darker specimens with weak diffuse bluish pigmentation, more concentrating on mid-dorsal area and at posterior borders of tergites (Figs 25). Feet pale. Discussion. This species is readily defined due to pale coloration, long furca, the presence of chaetae on anterior side of ventral tube, and unusual sensillar chaetotaxy.