Blasconura cordis sp. nov.

[Japanese name: inome-niseamime-ibotobimushi]

Figures 25–36, Table 3

Type material. Holotype: female, Japan, Okinawa, Miyako-jima (alt. 101 m, 24°45'05"N 125°22'31"E), 24-XII- 2021, Hiro Kasai leg. (NMNS, NSMT-Ap 604) . Paratypes: 3 females (NMNS, NSMT-Ap 605–607), same data as holotype .

Diagnosis. 2+2 unpigmented eyes on head. Body color light red alive and white in alcohol. Dorsal tubercles well developed, with tertiary granulation. Tubercle An fused to Cl and not fused to Fr. 2 tubercle Di very close to each other. Labrum chaetotaxy as 0/ 2, 2. Mandible with three teeth. Maxilla consists of 2 styliform lamellae. Ant. I and II with 7 and 11 chaetae respectively. Cephalic chaeta O absent. Cephalic tubercles Dl, L, and So fused with 14 chaetae. Chaetae formula of tubercle Di on Th. I–Abd. V as 1, 3, 3/2, 2, 2, 2, 3. Length of chaeta Di 1 in Abd. V 182–207µm. Tibiotarsi I–III with 19, 19, and 18 chaetae respectively. Unguis without an inner tooth.

Description. Body length:1.3–1.61 mm in adults.Color:Light red alive,white in alcohol.Eyes:2+2,unpigmented. Tubercles well developed on the dorsal side of head and tergite with tertiary granulation (Fig. 25). Types of dorsal ordinary chaetae: Macrochaetae Ml long, thickened, and barbulated (Figs 28, 33), some lateral and ventral chaetae weakly acuminate and slightly serrated. Macrochaetae Mc morphologically similar to long macrochaetae, but much shorter. Macrochaetae Mcc shorter than Mc, slightly barbulated, apically pointed. Mesochaetae and microchaetae similar to ventral chaetae, thin, smooth, and apically pointed. S–chaetae of tergites thin, smooth.

Antennal morphology and chaetotaxy (Figs 26–27 and Table 3c). Antenna 4-segmented. Ratio of antennal segments as I: II: III + IV = 1: 1: 1.8. Ant. I with 7 chaetae: dorsal 2 long chaetae serrated, others smooth. Ant. II with 11 chaetae: dorsal 2 long chaetae serrated and 1 short chaeta smooth or serrated, others smooth. Antennal macrochaetae located in subcuticular reticulation areas (Fig. 26). Ant. III dorsally fused to Ant. IV. AOIII comprises 2 short rods, each rod exposed in separate pits. Guard chaeta sgd positioned near the 2 rods (Fig. 26). Apical bulb trilobed.

Mouthparts. Labrum chaetotaxy 0/2, 2 (Fig. 31). Labium with 11 chaetae and papillae x absent (Fig. 32). Mandible with 3 teeth (Fig. 29). Maxilla styliform, maxillary head comprising 2 lamellae (Fig. 30).

Cephalic tubercles and chaetotaxy (Figs 25, 33, 36 and Table 3a, 3b). Tubercle An fused to Cl, not fused to Fr (Figs 25, 33). The middle of the anterior margin on tubercle An+Cl deeply furrow, forming a heart shape (Fig. 33). Dorso-lateral area with fused tubercle (Dl+L+So), with 14 chaetae (rarely 15 chaetae). 2 tubercles Di very close to each other, but not fused (Fig. 33). Length of macrochaetae in adults (n = 4); chaeta F 96 µm (89–116 µm), chaeta B 123µm (116–123 μm), chaeta A 100 µm (92–119 μm), chaeta Ocm 136 µm (122–139 μm), chaeta Ocp 90 µm (80– 90 μm), Chaeta Di1 135µm (113–135 µm), chaeta De1 140 µm (125–140 µm), lateral Ml 121–152 µm (110–163 µm), and lateral Mc 49 µm (40–57 µm). On the ventral side of head, group Vi with 6+6 chaetae, groups Vea, Vem and Vep with 5, 3, and 4 chaetae respectively (Fig. 36).

Body tubercles and chaetotaxy (Figs 25, 34 and Table 3d). Tubercle L on Abd. I-IV shifts backward or to the ventral side. Abd. V with 6 tubercles, De and Dl fused, and L situated ventrally. Weak cryptopygy. The length of chaeta Di1 on Abd. V in adults (n = 4) 190 µm (182–207 µm) (Fig. 28). Ventral chaetotaxy of Abd. I–VI (Fig. 34). Chaeta L2 on Abd. V thick and serrated (Fig. 34), and sometimes weakly pointed apically. VT with 4+4 chaetae. Furcular remnant with 4 chaetae. Genital plate with 20–29 chaetae in female.

Legs (Fig. 35 and Table 3d). Tibiotarsi I, II and III with 19, 19, and 18 chaetae respectively. Chaetae M present. Unguis without inner tooth and tenent hair (Fig. 35).

Etymology. The species epithet “cordis” is used here to mean “heart” and is in reference to the cephalic tubercle Cl + An heart shape.

Ecology. The new species inhabits among fallen branches in secondary forest in evergreen broad-leaved forests.

Remark. The new species is unique in the genus, with a cephalic tubercle An fused to Cl. Blasconura cordis sp. nov. is most similar to B. anamalensis Cassagnau, 1988 in having cephalic chaeta O absent, Ant. I and II with 7 and 11 chaetae respectively, and tubercle Di of Th. I with 1 chaeta. However, B. cordis sp. nov. differs from B. anamalensis in its cephalic tubercle Oc with 3 chaetae (in anamalensis 1), labrum chaetotaxy 0/2, 2 (in anamalensis 0/4, 2), tubercle De of Th. III with 5 chaetae (in anamalensis 4), and tubercle Di of Th. II with 3 chaetae (in anamalensis 2). B. triangulum sp. nov. is particularly similar in chaetotaxy to B. cordis sp. nov. However, the two differ in the following characteristics: number of chaetae of tubercle (Dl+L+So) on head (in B. cordis sp. nov. 14, in B. triangulum sp. nov. 15), length of cephalic chaeta F (in B. cordis sp. nov. 89–116 µm, in B. triangulum sp. nov. 63–86 µm), length of cephalic chaeta De1 (in B. cordis sp. nov. 125–140 µm, in B. triangulum sp. nov. 88–121 µm), length of chaeta Di1 on Abd. V (in B. cordis sp. nov. 182–207 µm, in B. triangulum sp. nov. 146–163µm), and chaeta L2 on Abd. V (in B. cordis sp. nov. developed, in B. triangulum sp. nov. weakly developed). The key for all species of the genus is as follows:

c) Chaetotaxy of antennae.