Folsomia pseudovtorovi Potapov & Gulgenova, 2013, sp. nov.

Folsomia pseudovtorovi sp. nov.

Figs 25–30

Type material. Holotype: female. Russia (East Siberia), Buryat Republic, Vitim Highland, Konda Basin, ca. 950 m alt., bushes of Betula nana with Carex and Salix, Birkhasan river (ca 14 km N Telemba), 6.vii.2008. 29 paratypes from the same locality, leg. A. Gulgenova. Holotype and 15 paratypes in MSPU; 14 paratypes in BSU.

Other material. Vitim Highland, Konda Basin, damp meadow with Carex in depression, near Birkhasan river (ca 14 km N Telemba), ca. 950 m alt., 23.viii.2009, leg. A. Gulgenova.

Description. Body size 0.7–0.8 mm. Without pigmentation, shape of body as typical for the genus, posterior part of abdomen elongated. Cuticle with bands of more coarse granulation which on Abd.IV–VI well mark "unchaetaceous" bands between segments (Fig. 29) Ocelli absent. PAO slender, weakly constricted, 1.1–1.2 as long as width of Ant I and 1.7–2.0 as long as inner unguis length (Fig. 28). Maxillary outer lobe with 4 sublobal hairs, maxillary palp simple. Labral formula as 4/5,5,4. Labium with 5 papillae (А–Е), guard chaetae e7 present, 3 proximal and 4 basomedian chaetae. Ventral side of a head with 4–5+4–5 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 1 latero-distal s, Ant.III without bms and with 5 distal s (including 1 lateral), without additional sensilla. Sensilla on Ant.4 weakly differentiated. Organite small.

Sensillary formula as 4,3/2,2,2,3,5 (s), 1,0/1,0,0 (ms). Tergal sensilla shorter than common chaetae. Medial sensilla on Th.III–Abd.III situated in mid-tergal position, on Th.II in anterior part of the tergite, on Abd.I–III between Mac1 and Mac2. Abd.V with 5 sensilla arranged with 3 dorsal ones (al, accp1, accp2) being long and slender (al shorter than others), 1 lateral accp3 subequal to al, and short accp 4 in ventral position (Fig. 30). Macrochaetae smooth, middle-sized, 1,1/3,3,3 in number, medial ones on Abd.V 0.9–1.2 as long as dens and 2.3– 3.4 times longer than mucro. Foil chaetae absent. Axial chaetotaxy as 9–10,7/4,4,5. Thorax without ventral chaetae.

Unguis of normal shape, without lateral and inner teeth. Empodial appendage longer than half of unguis (0.6– 0.7). Tibiotarsi usually with 1–2 additional chaetae on Leg I and II (22–23 chaetae in all), and rather many ones on Leg III. Tibiotarsal tenent chaetae pointed. VT with 4+4(5) laterodistal and 6–8 posterior chaetae, anteriorly without chaetae (Fig. 27). Tenaculum with 4+4 teeth and one chaeta. Anterior furcal subcoxae with 6–8, posterior one with 3 chaetae. Anterior side of manubrium with a pair of chaetae (Fig. 26). Posterior side of manubrium with 3+3 laterobasal, 2 apical chaetae (ap), 2+2 chaetae in distal transversal row (M1, L1), one pair of lateral chaetae, and 4+4 (more rarely with 3 or 5 on one side) in central part (Fig. 26). Dens with 8 anterior chaetae arranged as 1,1,1,2,3 (Fig. 25). Posterior side of dens crenulated at the middle and with 3 normal chaetae. Mucro bidentate. Ratio of manubrium:dens:mucro = 4.4–4.7: 2.7–3.2: 1.

Discussion. The simple maxillary palp puts the species in the ' heterocellata ' group. Other important characters include the anterior position of median s on Th.II, two small dorsal basal ms on Ant.I, and foil chaetae absent. This indicate a close relation to the ' quadrioculata ' group. In the morphology of furca it resembles F. quadrioculata and related species which combine ' quadrioculata ' group sensu strictu (Fjellberg 2007). By many chaetae on VT and manubrium, ocelli absent, and microsensillar formula the new species is like F. vtorovi but differs in simple (vs. bifurcate) maxillary palp and bms on Ant.III absent (vs. present). For comparison with other species of ' quadrioculata ' group s.s. see reviews of Ding et al. (2006) and Ji et al. (2007).

Distribution and ecology. Known only from two rather damp sites of the Konda Basin (Fig. 1: loc. 1).

Etymology. The name reflects the similarity to F. vtorovi.