Holotype female, 4 female and 1 male paratypes. China: Jilin Province: Changbai Mountain Range (alt. 1763m, 41.755265°S, 127.941123°W): 15.VIII.2009, litter and soil, Berlese extraction, Wu Dong-hui leg.

Holotype and 5 paratypes on slides are deposited in the Key laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun.

Pso formula as 32/133/44454 dorsally and 11/000/00000 ventrally; subcoxa 1 of legs I–III with 1 pso each; psx formula as 00/000/222200 ventrally, absent dorsally; S-chaetae formula as 11/011/222111 dorsally and 11/000/000100 ventrally; Ant. III sensory organ composed of 5 papillae, 5 guard chaetae, 2 small sensory rods, 2 granulated sensory clubs; Abd. V tergum with one dorsal axial chaeta (p0), Abd. VI with two axial chaetae (a0 and p0); tibiotarsi of legs I, II and III with 20, 20 and 19 chaetae; anal spines present on indistinct papillae, as long as inner edge of unguis.

Body color white in alcohol. Size 0.70–0.82 mm, holotype: 0.78 mm. Body slender and elongated.

Pseudocelli (pso) formula as 32/133/44454 dorsally and 11/000/00000 ventrally (Figs 1A, 2C); subcoxa 1 of legs I–III with 1 pso each. Parapseudocelli (psx) formula as 00/000/222200 ventrally and absent dorsally (Figs 1A, 2C); subcoxa 1 of legs I–III with 2 psx each. Pseudopore (psp) formula as 00/011/111100 dorsallyand 00/111/000x00 ventrally (Figs 1A, 2C).

S-chaetae cylindrical, well differentiated, formula as 11/011/222111 dorsallyand 11/000/000100 ventrally (Figs 1A, 2C); subcoxae 2 of legs I, II and III with 0, 0 and 1 S-chaeta respectively (Fig. 2D). Two posterior S-chaetae (Sp) present on head. S-microchaetae tiny and blunt, present on Th. II–III (Fig. 1A).

Head. Antennae short and distinctly segmented, 0.8 times as long as head. Length ratio of antennal segments I: II: III: IV = 1: 1.8: 1.8: 2. Ant. IV with two distinct thickened S-chaetae, subapical organite with apex globular and basolateral ms just above posterior chaetae (Fig. 1C). Ant. III sensory organ composed of 5 papillae, 5 guard chaetae, 2 small sensory rods, 2 granulated sensory clubs, the outer about twice as large as the inner, and a lateral ms (Fig. 1D). Ant. II with 14 chaetae. Ant. I with 8 chaetae. Antennal base without distinct granulation. PAO located on cuticular furrow built with a 3–4 lobed vesicle (Fig. 1B). Dorsal cephalic chaeta d0 absent, 3+3 p-chaetae between posterior a-pso on head (Fig. 1B). Mandible with strong molar plate and 4 apical teeth. Maxilla bearing 3 teeth and 6 lamellae. Maxillary palp simple with 1 basal chaeta and 2 sublobal hairs. Labral chaetae formula 4/342. Labium with 6 proximal, 4 basomedian (E, F, G, f) and 6 basolateral (a, b, c, d, e, e’) chaetae (Fig. 2B); labial type ABC, papillae A–E respectively with 1, 4, 0, 3, 3 guard chaetae (Fig. 1E). Postlabial chaetae 4+4 along ventral groove (Fig. 2B).

Body chaetotaxy. Ordinary chaetae differentiated in meso- and macrochaetae. Th. I tergum with 7+7 chaetae dorsally (Fig. 1A). Th. II–III and Abd. I–III terga with three chaetae on both side of axial line and no dorsal axial chaetae. Abd. IV tergum with one dorsal axial chaeta (m0), Abd. V with one dorsal axial chaeta (p0), Abd. VI with two axial chaetae (a0 and p0) (Fig. 2A). Th. I, II and III sterna with 0+0/1+1/1+1 (2+2) chaetae.

Appendages. Subcoxa 1 of legs I–III with 4, 5 and 5 chaetae, subcoxa 2 with 1, 4 and 4 chaetae respectively. Tibiotarsi of legs I, II and III with 20 (1, 8, 11), 20 (1, 8, 11) and 19 (1, 7, 11) chaetae (Fig. 1F). Unguis without teeth. Unguiculus slender and pointed, 0.6 times as long as inner edge of unguis, with inner basal lamella (Figs 1F, 2D). Ventral tube with 6+6 distal chaetae and 2+2 basal chaetae, without anterior chaetae. Furca reduced to a small cuticular fold with 1+1 dental chaetae posteriorly; two manubrial rows of chaetae present (Fig. 2C).

Female genital plate with 14 chaetae; in our specimens, the only male is juvenile. Anal valves with numerous acuminate chaetae; each lateral valve with a0 and 2a1; upper valves with chaetae a0, 2b1, 2b2, c0, 2c1, 2c2 (Fig. 2E). Anal spines present on indistinct papillae, as long as inner edge of unguis (Fig. 1A).

Named after the mountain range where we found the new species.

Found in coniferous forest.

The new species has the same dorsal pseudocelli formula (32/133/44454) and number of papillae in Ant. III sensory organ (5) as Micraphorura uralica (Khanislamova, 1986), but they can be easily distinguished by number of guard chaetae on Ant. III sensory organ (5 in changbaiensis sp. n., 4 in uralica), ventral pseudocelli formulae (11/000/00000 in changbaiensis sp. n., 11/000/11120 in uralica), ventral parapseudocelli formulae (00/000/222200 in changbaiensis sp. n., indistinct in uralica), pseudocelli on subcoxa 1 of legs I–III (1, 1, 1 in changbaiensis sp. n., 2, 3, 3 in uralica), dorsal axial chaeta on Abd. V (m0 in changbaiensis sp. n., absent in uralica), and number of chaetae on tibiotarsi (20, 20, 19 in changbaiensis sp. n., 19, 19, 18 in uralica).

Holotype male, 2 female and 5 male paratypes. China: Jilin Province: Changbai Mountain Range (alt. 689m, 43.037640°S, 128.199653°W): 3.X.2011, litter and soil, Berlese extraction, Tang Xu-guang leg.

Holotype and 7 paratypes on slides are deposited in the Key laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun.

Pso formula as 43/144/54464 dorsally and 11/000/00000 ventrally; subcoxa 1 of legs I–III with 1 pso each; psx formula as 00/000/222401 ventrally and absent dorsally; S-chaetae formula as 11/011/222111 dorsally and 11/000/000100 ventrally; Ant. III sensory organ composed of 5 papillae, 5 guard chaetae, 2 small sensory rods, 2 granulated sensory clubs; Abd. V without dorsal axial chaetae, Abd. VI with two axial chaetae (a0 and p0); tibiotarsi of legs I, II and III with 20, 20 and 19 chaetae; anal spines present on indistinct papillae, 0.75 times as long as inner edge of unguis.

Body color white in alcohol. Size 0.80–1.04 mm; holotype: 0.90 mm. Body slender and elongated.

Pseudocelli (pso) formula as 43/144/54464 dorsally and 11/000/00000 ventrally (Figs 3A, E); subcoxa 1 of legs I–III with 1 pso each (Fig. 4C). Parapseudocelli (psx) formula as 00/000/222401 ventrally and absent dorsally (Figs 3A, E); subcoxa 1 of legs I–III with 1 psx each (Fig. 4C). Pseudopore (psp) formula as 00/011/111100 dorsally and 00/111/000x00 ventrally (Figs 3A, E).

S-chaetae cylindrical, well differentiated, formula as 11/011/222111 dorsally and 11/000/000100 ventrally (Figs 3A, E); subcoxae 2 of legs I, II and III with 0, 0 and 1 S-chaeta respectively (Fig. 4C). Two posterior S-chaetae (Sp) present on head. S-microchaetae tiny and blunt, present on Th. II–III (Fig. 3A).

Head. Antennae short and distinctly segmented, as long as head. Length ratio of antennal segments I: II: III: IV = 1: 2: 2: 2. Ant. IV with two distinct thickened S-chaetae, subapical organite with apex globular and basolateral ms just above posterior chaetae (Fig. 3C). Ant. III sensory organ composed of 5 papillae, 5 guard chaetae, 2 small sensory rods, 2 granulated sensory clubs, the outer about twice as large as the inner, and a lateral ms (Fig. 3B). Ant. II with 15 chaetae. Ant. I with 9 chaetae. Antennal base with distinct granulation. PAO located on cuticular furrow built with a 3 lobed vesicle (Fig. 4A). Dorsal cephalic chaeta d0 absent, 3+3 p-chaetae between posterior a-pso on head (Fig. 4A). Mandible with strong molar plate and 4 apical teeth. Maxilla bearing 3 teeth and 6 lamellae. Maxillary palp simple with 1 basal chaeta and 2 sublobal hairs. Labral chaetae formula 4/342. Labium with 6 proximal, 4 basomedian (E, F, G, f) and 6 basolateral (a, b, c, d, e, e’) chaetae; labial type AC, papillae A–E respectively with 1, 4, 0, 3, and 2 guard chaetae (Fig. 3D). Postlabial chaetae 4+4 along ventral groove.

Body chaetotaxy. Ordinary chaetae differentiated in meso- and macrochaetae. Th. I tergum with 6+6 chaetae dorsally (Fig. 3A). Th. II–III and Abd. I–III terga with three chaetae on both side of axial line and no dorsal axial chaetae. Abd. IV tergum with one dorsal axial chaeta (m0), Abd. V without dorsal axial chaetae, Abd. VI with two axial chaetae (a0 and p0) (Fig. 3A). Th. I, II and III sterna without chaetae.

Appendages. Subcoxa 1 of legs I–III with 4, 5 and 5 chaetae, subcoxa 2 with 1, 4 and 4 chaetae respectively. Tibiotarsi of legs I, II and III with 20 (1, 8, 11), 20 (1, 8, 11) and 19 (1, 7, 11) chaetae (Fig. 4B). Unguis without inner teeth, with lateral teeth. Unguiculus slender and pointed, 0.6 times as long as inner edge of unguis, with inner basal lamella (Fig. 4B). Ventral tube with 6–7+6–7 distal chaetae and 2+2 basal chaetae, without anterior chaetae. Furca reduced to a small cuticular fold with 2+2 dental chaetae in two rows posteriorly; two manubrial rows of chaetae present (Fig. 3E).

Female genital plate with 17 chaetae (Fig. 4D), male genital plate with 19–24 chaetae. Anal valves with numerous acuminate chaetae; each lateral valve with a0 and 2a1; upper valves with chaetae a0, 2b1, 2b2, c0, 2c1, 2c2 (Fig. 4E). Anal spines present on indistinct papillae, 0.75 times as long as inner edge of unguis (Fig. 3A).

Named for the similarity with the Korean species Oligaphorura montana Weiner, 1994.

Found in coniferous forest.

The new species is very similar to the species montana collected in the mountain of North Korea, sharing the following characters: an increased number of pseudocelli dorsally; well marked base of antenna with 1 pseudocellus and 3 dorsal pseudocelli outside; subcoxa 1 of legs I–III with 1 pseudocellus each; dorsally S-chaetae formula as 11/011/22211 from head to Abd. V; S-microchaetae present on Th. II–III; head with chaeta p1 level with p2; Th. I, II and III sterna without chaetae; anal spines 0.75 times as long as inner edge of unguis; claw without inner teeth but with one lateral tooth; unguiculus with basal lamella. But they can be separated easily by the number of pseudocelli on Abd. V and VI terga (5 and 3 in montana versus 6 and 4 in pseudomontana sp. n.), parapseudocelli on the body (indistinct in montana, versus 00/000/222401 by half-sternite in pseudomontana sp. n.), the number of chaetae on Th. I tergum (7+7 in montana versus 6+6 in pseudomontana sp. n.), and the number of chaetae on tibiotarsi (19, 19, 18 in montana versus 20, 20, 19 in pseudomontana sp. n.).