Isotomidae (Collembola) of Buryat Republic. II. A revision of the genus Folsomia Author Potapov, Mikhail Author Gulgenova, Ayuna text Zootaxa 2013 3682 2 305 330 journal article 10.11646/zootaxa.3682.2.6 4930efae-7d79-426c-9cca-22ef026974ef 1175-5326 254495 E42A2F18-9226-4CA5-8C71-C1302F01D04A Folsomia fumosa sp. nov. Figs 9–15 Type material. Holotype : female. Russia (East Siberia), Irkutsk Area, W Khamar-Daban Range, valley of Slyudyanka River, ca. 10 km SW of Slyudyanka, ca. 1000 alt., litter of poplar wood near the river with Bergenia and Equisetum .), 28.viii.2008 , leg. M. Potapov & V. Kadnikov. 4 paratypes from the same locality. 10 paratypes from nearly the same locality, 1300 to 1800 m alt., in taiga belt, in coniferous litter and grass turf. Holotype and 5 paratypes in MSPU ; 5 paratypes in BSU . Other material. Vicinities of Ulan-Ude, ca. 20 km of highway Ulan-Ude–Gremyachinsk, pass, mixed taiga forest, southern slope, 24.ix.2012 ., leg. N. Nefed'yeva.Shore of Baikal Lake, estuary of Selenga River, Posol'sky Sor Bay, near Baikal'sky Priboy station, weed debris near the water, 23.viii.2011 . leg. A. Gulgenova and L. Vanyavina.NW Buryatia, Barguzinsky Range, ca. 10 km W Barguzin, upper flow of Gremyachaya Brook, subalpine belt ( Pinus pumila ), ca. 1400 m alt., under Bergenia , and ca. 900 m alt., eutrophic mosses near the brook, 20.viii.2008 . leg. A. Gulgenova and M. Potapov. Description. Body size from 0.5 to 0.7 mm. With scattered black pigment grains, general pigmentation varies from almost white (rarely) to spotty fumose ( Fig. 11 ). Body of common shape for the genus. Cuticle with bands of coarse granulation. Ocelli absent. PAO slender, weakly constricted, a little longer than width of Ant I (1.0–1.2) and 1.6–1.9 as long as inner unguis length ( Fig. 10 ). Maxillary outer lobe with 4 sublobal hairs, maxillary palp bifurcate. Labral formula as 4/5,5,4. Labium with 5 papillae (А–Е), e7 present, 3 proximal and 4 basomedian chaetae. Ventral side of a head with 4+4 chaetae. Ant.I with 2 ventral sensilla (s) and 3 small basal microsensilla (bms), 2 dorsal and 1 ventral, Ant.II with 3 bms and a latero-distal s, Ant.III without bms and with 5 distal s (including one lateral), without additional sensilla. Sensilla on Ant.4 weakly differentiated. Organite stick-like, swollen at the tip. Sensillary formula as common for the genus, 4,3/2,2,2,3,5 (s) and 1,0/1,0,0 (ms). Tergal sensilla a little shorter than common chaetae and rather well distinguishable. Medial sensilla on Th.II–Abd.III situated in mid-tergal position, on Abd.I–III between Mac1 and Mac2 ( Fig. 12 ). Abd.V with 5 sensilla arranged with 3 dorsal ones (al, accp1, accp2), long and slender, 1 lateral middle-sized slightly thickened, and a short sensillum in ventral position ( Fig. 14 ). Macrochaetae smooth and short, 1,1/3,3,3 in number, medial ones on Abd.V about as long as dens (0.9– 1.1) and 2.6–3.3 times longer than mucro. Foil chaetae at the tip of abdomen absent. Axial chaetotaxy as 8–9,7–8/ 4,4,4. Thorax without ventral chaetae. Unguis of normal shape, without lateral and inner teeth. Empodial appendage about half as long as unguis. Tibiotarsi with 1–3 additional chaetae on Leg I and II (21–24 chaetae), and with up to 6 additional chaetae on Leg III. Tibiotarsal tenent chaetae pointed. VT with 3+3 laterodistal and 5–6 posterior chaetae, anteriorly without chaetae. Tenaculum with 4+4 teeth and a chaeta. Anterior furcal subcoxae with 3–5, posterior one with 3 chaetae. Anterior side of manubrium with a pair of chaetae ( Fig. 9 ). Posterior side of manubrium as in F. palaearctica , with 3+3 laterobasal, 2 apical chaetae (ap), 2+2 chaetae in distal transversal row (M1, L1), one pair of lateral chaetae, and 2+ 2 in central part. Dens with 8 anterior chaetae arranged as 1,1,1,2,3 ( Fig. 9 ). Posterior side of dens crenulated at the middle and with 3 normal chaetae (2 basal and 1 at the middle), without subapical dorsal chaeta. Mucro bidentate. Ratio of manubrium:dens:mucro = 3.6–4.7: 2.5–3.2: 1. Discussion . The species belongs to ' quadrioculata ' group and mostly resembles F. palaearctica : they share small body size, few chaetae on VT and posterior side of manubrium, bms on Ant.III absent, 1,0/1,0,0 microsensilla. The general appearance of the two mentioned species is also similar. F. f u m o s a sp. nov. differs in the absence of ocelli (present in F. palaearctica ), 'p-position' of corner sensilla on Th.II ( Fig. 13 ) (vs. in front of p-row of chaeta), and 8 (vs. 7) anterior chaetae on dens. Both species show similar colouration of the body but in mixed populations F. palaearctica readily differs by distinct dark ocelli. Among blind forms F. f u m o s a sp. nov. resembles the Carpathians F. albens Kaprus’ & Potapov, 1999. The latter species is much paler, has a longer PAO, ms on Abd.I absent, and basal ms on Ant.III present. Distribution and ecology . F. f u m o s a sp. nov. is probably a local species since it was recorded only in mountain ranges along southern and eastern shores of the Baikal Lake ( Fig. 15 ). It is rather common in Khamar- Daban Range where it is an eurytopic species and it often occurs together with the closely related and somewhat habitually similar species F. quadrioculata , F. manolachei and F. palaearctica . F. f u m o s a sp. nov. is more rare in southern part of Barguzinsky Range and absent both in eastern and western areas (Tunkinskiye Gol'tsy) ( Fig. 1 : loc. 7, 9, 11, 12). Survives in rather dry conditions (bark of trees, sands). Etymology. The name is given after the distinctive softly “fumoso” (Latin) coloration.