Vitronura clavata Jiang, Wang & Zhu, 2025, sp. nov.

Vitronura clavata sp. nov. Figs 3, 14–22, Tables 3–5 Type material. Holotype: Female, Liansanguai, Shaping Town, Taoyuan County, Hunan Province, China. coordinates: 28°33’13.37”N, 111°23’42.43”E, alt. 444m, under leaves nearby a road in evergreen and deciduous broad-leaved mixed forest (Fig. 13). leg. Ji-Gang Jiang, Yi Wang, Pei-Ting Zhu, Jing Shu, Hong Qi, 17.XI.2023 (2023111704). Paratypes: two females and two males, same data as the holotype. Type material is deposited at the Key Laboratory of Zoology, Hunan University of Arts and Science (HUAS), Changde, Hunan Province, China. Etymology. The name of the species is derived from its clavate macrochaetae on dorsum. Diagnosis. Two eyes per side; cephalic chaeta O present; body tubercles well differentiated; cephalic tubercles Dl, L and So fused; mandible with a basal tooth, a middle tooth and four apical teeth; maxilla with two lamellae, each with one tooth; dorsal body macrochaetae usually clavate. Description. Body length: holotype female 2.0 mm, females 2.0– 2.9 mm; males 1.4–1.8 mm. Color: living specimens red, whitish in ethanol (Fig. 3). Chaetal morphology. Dorsal ordinary chaetae of five types. Long macrochaetae (Ml) smooth, clavate or with pointed tip (Fig. 14a–c). Short macrochaetae (Mc) shorter than Ml, clavate and with variable lengths (Fig. 14d–f). Very short macrochaetae (Mcc) morphologically similar to but shorter than Mc, with variable lengths (Fig. 14g –j). Mesochaetae (me) on the dorsum, usually thicker than those on the ventral side. All me smooth, pointed and with variable lengths (Fig. 14k–m). S-chaetae (s) on terga thin, smooth, usually shorter than Mc and equal to the longest me (Fig. 14n). Head. Eyes 2+2, uncolored, one anterior, but not included in Oc tubercle, the other one on the posterior part of Oc tubercle. Antenna four-segmented (Fig. 15). Ant. I with 7 chaetae. Ant. II with 11 chaetae. Ant. III dorsally fused to Ant. IV. Guard chaeta sgd of Ant. III not migrated distally, slightly below to the level of the two sensory rods. Ant. IV dorsally with eight subequal, slightly thickened blunt sensilla (S1–8), apical bulb trilobed, subapical organite (or) present. Ventral side of Ant. IV with some pointed or slightly blunt chaetae (Fig. 16). On ventral side of Ant. III, Vi, Vc and Ve with 4, 4, 5 chaetae respectively (Fig. 16). Mandible consisting of one basal, one middle and four apical teeth (Fig. 17). Maxilla consisting of two lamellae, each lamella apically with a tooth, the two lamellae usually stuck together, so only one apical tooth clearly observable (Fig. 18). Oral cone long, labrum ogival, labral formula as 0/2, 2. Labium with 11 chaetae, with no papillae x (Fig. 19). Cephalic dorsal tubercles and chaetotaxy as in Table 3 and Fig. 20. Central area of head with six tubercles: one Cl, one Fr, two Oc and two An; chaeta O present on tubercle Fr as a me. Dorso-posterior area with four separate tubercles: two Di and two De, chaeta Di2 and De2 as mes on tubercle De. Line of chaetae Di1–De1 crossing line Di2–De2 on head (cross-type). Tubercles Dl, L and So on dorsal lateral area fused, with 12 chaetae. Ventral chaetotaxy of head. Group Vi with five chaetae, groups Vea with four, Vem with three and Vep with four chaetae, respectively (Fig. 19). Thorax (Fig. 20 and Table 4). Th. I with 3+3 tubercles, Di, De, Dl with 1, 2, 1 chaeta respectively; Th. II with 4+4 tubercles, Di with three chaetae, De with four (3+s) chaetae, Dl with five (3+s+ms) chaetae, tubercle L with three chaetae. Th. III with 4+4 tubercles, Di with three chaetae, De with five (4+s) chaetae, Dl with four (3+s) chaetae, and L with three chaetae. Chaetotaxy of thorax and legs listed in Table 4. Unguis with a basal inner tooth; unguiculus absent. Chaeta M present on tibiotarsus. Abdomen (Figs 21–22 and Table 4). Abd. I–III with 4+4 tubercles each, Di with two, De with four (3+s), Dl with two and L with 3 chaetae, respectively. Abd. IV with 4+4 tubercles, Di with two, De with three (2+s), Dl with three and L with six chaetae, respectively. Abd. V dorsally with 2+2 tubercles, two Di separated, each with three chaetae, tubercle De with only one sensillum, and fused to tubercle Dl, Dl with four chaetae. Abd. VI with 1+1 tubercles, with seven chaetae on each tubercle (Fig. 21). VT with 4+4 chaetae (Fig. 22). Furcular remnant with 4 chaetae (Fig. 22). Ecology. The new species was found in the forest litter. Remarks. Vitronura clavata sp. nov. strongly resembles V. qingchengensis Jiang & Yin, 2012, V. paraacuta Wang, Wang & Jiang, 2016, V. setaebarbulata Gao, Bu & Palacios-Vargas 2012 and V. dentata Deharveng & Weiner, 1984 in the presence of three chaetae on cephalic tubercle Oc, three chaetae on cephalic tubercle De, chaeta O on tubercle Fr, the distinctly separate Di tubercles on head, an inner tooth on claw. However, the new species can be distinguished from the above species by the following features: structure of mandible (mandible with six teeth in the new species, versus with three teeth in V. dentata, four teeth in V. paraacuta, five teeth in V. qingchengensis, and 7–8 teeth in V. setaebarbulata); shape of body macrochaetae (smooth and clavate in the new species versus blunt and strongly barbulate in V. setaebarbulata, smooth and blunt in V. qingchengensis); number of chaetae on tubercle De+DL of Abd. V (5 (4+s) in the new species versus 4 (3+s) in V. dentata); the arrangement of tubercles Dl, L and So on head (tubercles Dl, L and So fused to each other in the new species versus Dl separate from tubercle L+So in V. paraacuta). Vitronura clavata sp. nov. is also similar to V. joanna (Coates, 1968) from South Africa by having six teeth on mandible, chaeta O on tubercle Fr, three chaetae on tubercle Oc, five chaetae on tubercle De+Dl of Abd. V and similar shape of body chaetae. However, they differ in the claw inner tooth (with an inner tooth in V. clavata sp. nov., without in V. Joanna), and number of chaetae on cephalic tubercle De (three chaetae in V. clavata sp. nov., two in V. Joanna). Differences between V. clavata sp. nov. and its congeners are summarized in Table 5.