Paranura alpicola Kasai sp. nov.

[Japanese name: Takane-ibonashi-tobimushi]

Figs 24–34, Tables 5–6

Type material. Holotype: female, Japan, Honshu, Nara Prefecture, Yoshino-gun, Totsukawa-mura, Mount Syakagatake (alt. 1,416 m, 34°05'46"N 135°52'45"E), beech forest, rotten fallen branch, 20-IX-2021, Hiro Kasai leg. (NMNS, NSMT-Ap 683) . Paratypes: 2 females (NMNS, NSMT-Ap 684–685) and male (NMNS, NSMT-Ap 686), same data as holotype; 2 females (NMNS, NSMT-Ap 687–688), same locality and habitat as holotype, 13-IX-2020, Hiro Kasai leg.

Etymology. The name of the new species refers to alpine region habitat.

Diagnosis. 3+3 black eyes on head. Yellow body color while alive and white in alcohol. Body very thick and plump. Some tubercles poorly developed on the dorsal side and reticulations absent.Ant. II with 11 chaetae. Chaetae O, A, E, and three ocular chaetae present on head. Lateral area on head with 6 chaetae Dl and 9 chaetae (L+So). Th. II–III with 2 and 3 ordinary chaetae De respectively. Abd. IV with 2 ordinary chaetae Dl. Tubercles Di on Abd. V developed and separate, each with 3 chaetae Di. Abdomen without clavate chaetae. Furcal remnant with 4 mesochaetae and no microchaetae. Tibiotarsi with chaeta M.

Description. Body length (without antennae) 1.29–2.21 mm in adults. The body yellow while alive (Fig. 24) and white in alcohol. 3+3 black eyes, two anterior and one posterior. Body very thick and plump.

Chaetal morphology. Five types of dorsal ordinary chaetae. Long macrochaetae (Ml) relatively long and thick, feebly or not serrated, and apically acuminated (Fig. 32); some lateral chaetae longer and strongly acuminate apex. Short macrochaetae (Mc) and very short macrochaetae (Mcc) morphologically similar to Ml, but much shorter. Mesochaetae (me) and microchaetae (mi) similar to ventral chaetae: thin, smooth, and pointed. S–chaetae of tergites thin and smooth.

Antennal morphology and chaetotaxy. Antenna 4-segmented. Ratio of antennal segments as I: II: III + IV = 1:1.1–1.3:1.8–2.3. Dorso-central area on Ant. III–IV granulated (Fig. 26). S-chaetae of Ant. IV short and thick, S1 and S2 slightly thinner than others (Fig. 26). Apical bulb distinct and trilobed. Chaetotaxy of antennae shown in Table 5b and Figs 26−27.

Mouthparts. Buccal cone relatively long and rounded at apex. Labrum chaetotaxy 0/2,2 (Fig. 29). Labium with 4 basal, 3 distal, and 3 lateral chaetae, papillae x absent (Fig. 28). Mandible with 3 teeth. Maxilla styliform.

Cephalic tubercles and chaetotaxy. Tubercles and reticulations not developed. Chaetotaxy of the central area complete (Fig. 25). Lateral area with 6 chaetae Dl and 9 chaetae (L+So) (L1–4, So1, So3–6). Dorsal chaetotaxy of the head shown in Table 5a and Fig. 25. Group Vi with 6+6 chaetae. Groups Vea, Vem, and Vep with 4, 2–3 and 4 chaetae respectively.

Body tubercles and chaetotaxy. Some tubercles poorly developed, reticulations absent (Fig. 25). Tubercles Di on Abd. V developed and separate, around the tubercles Di weakly raised (Fig. 25). Th. II–III with 2 (Ml+mi) and 3 (Ml+ 2mi) ordinary chaetae De respectively, microchaeta De2 situated far from long macrochaeta De1 (Figs 30, 31). Abd. VI weakly bilobed. Dorsal chaetotaxy shown in Table 6 and Fig. 25. Furcal remnant with 4 mesochaetae and no microchaetae. Genital plate with 13–23 and 26 chaetae in females and males respectively. An with 2–3 mi (1 anterior and 2 posterior), rarely absent. Ventral chaetotaxy shown in Table 6 and Fig. 34.

Legs. Tibiotarsi I, II, and III with 19, 19, and 18 chaetae respectively, chaeta M present. Unguis without inner tooth (Fig. 33). Chaetae B4 and B5 relatively long. Chaetotaxy of the legs shown in Table 6 and Fig. 33.

Remarks. Paranura alpicola sp. nov. is most similar to P. chiangdaoensis Deharveng, 1989 from Thailand, having 3+3 eyes, with chaetae O, E, and 3 ocular chaetae present on head. However, this new species is clearly distinguishable by its 2,2 labral chaetae (2,4 in P. chiangdaoensis), 6 chaetae Dl on the head (4–5in P.chiangdaoensis), tubercles Di on Abd. V separate (in P. chiangdaoensis fused), and 7 chaetae on Abd. Vl (6 in P. chiangdaoensis). This new species is also similar to P. colorata Mills, 1934 sensu Simón Benito & Palacios-Vargas (2008) . However, they differ in presence of chaeta E on the head (absent in P. colorata), 2 ordinary chaetae De on Th. II (3 in P. colorata), and 2 ordinary chaetae Dl on Abd. IV (4 in P. colorata).