Tomocerus (Ocreatomurus) gyirongensis, Yu & Xue & Zhang, 2025

Tomocerus (Ocreatomurus) gyirongensis sp. nov.

Figs 1–14 View FIGURES 1–3 View FIGURES 4–9 View FIGURES 10–14 , Table 1 View TABLE 1

Type material. Holotype: male on slide, coniferous and broad-leaved mixed forest, Gyirong Valley , Gyirong County, Xigaze , Xizang Autonomous Region, China, 85°15.141′E, 28°26.352′N ( WGS84 ), alt. 2965 m, 6.viii.2018, leg. Daoyuan Yu, Yiming Wei and Chunyan Qin (Sample code 18XZ13) GoogleMaps . Paratypes: one female, two males and one juvenile on slides, 19 subadults and juveniles in ethanol, same data as holotype; four subadults in ethanol, under a wood board in Jipu Village , Gyirong County, Xigaze , Xizang Autonomous Region, China, 85°19.693′E, 28°22.523′N, alt. 2765 m, 7.viii.2018, leg. Daoyuan Yu, Yiming Wei and Chunyan Qin (Sample code 18XZ15). All types deposited in NJAU GoogleMaps .

Description. Body length 3.0– 4.3 mm (average 3.8, five specimens). Body ground color pale yellow. Ant. III and IV purple. Diffuse reddish-purple pigment present mainly on Ant. I and II, head, coxae, tibiotarsi, ventral tube, and manubrium. In juveniles ( Fig. 1 View FIGURES 1–3 ), pigment on head distributed more evenly, and light reddish-purple pigment also around bothriotricha on terga, forming diffuse patches on Th. II and spots on other segments. In subadults ( Fig. 2 View FIGURES 1–3 ) and adults ( Fig. 3 View FIGURES 1–3 ), pigment on head concentrating anteriorly around mouth and antennal bases, and the patterns around bothriotricha becoming indistinct. In fully grown adults ( Fig. 3 View FIGURES 1–3 ), purple pigment more intense, becoming brownish.

Intact four-segmented antennae 0.75–0.81 × length of body (average 0.78, two specimens). Length ratio of Ant I: II: III: IV = 1.0: 1.6: 8.5–10.1: 0.9–1.2. Ant. III basally with 3–8 scales. Cephalic dorsal macrochaetotaxy as in Fig. 4 View FIGURES 4–9 . Posterior margin of head with 35–40 chaetae on each side.

Pattern of body macrochaetotaxy as in Fig. 5 View FIGURES 4–9 .

Single chaeta of femoral organ longer than that of trochanteral organ ( Fig. 6 View FIGURES 4–9 ). Tibiotarsi I, II, III ventrally with 8–10, 8–9, 7–9 strong chaetae, 5–8, 7–8, 7–9 of them blunt and spine-like, respectively ( Fig. 7 View FIGURES 4–9 ). Tenent hair 0.8–1.0 × the length of inner edge of unguis; accessory chaetae on tibiotarsi I and II almost equal to each other, and subequal to or shorter than pretarsal chaetae; on tibiotarsus III, anterior accessory chaeta longer than pretarsal chaetae, while posterior accessory chaeta subequal to pretarsal chaetae; guard chaetae 0.8–0.9 × the length of tenent hair. Unguiculus about 0.56–0.64 × the length of unguis (average 0.58, four specimens), its inner edge with 0–1 tooth ( Fig. 8 View FIGURES 4–9 ).

Ventral tube scaled on both faces; anterior face with 28–50 (average 38, three specimens) chaetae on each side; posterior face with 82–122 (average 103, three specimens) chaetae; each lateral flap with 137–170 (average 149, three specimens) chaetae and 2–8 scales. Anterior face of tenaculum unscaled, with 14–16 (average 15, three specimens) chaetae ( Fig. 9 View FIGURES 4–9 ). Ratio manubrium: dens: mucro = 3.3–3.9: 4.4–5.0: 1.0. Manubrium laterally with 9–10 strong chaetae; dorsally with 211–301 (average 252, three specimens) chaetae of different sizes on each dorsal chaetal strip, 6–12 (average eight, four specimens) pseudopores almost arranging in a file and scale strip running from base to about 3/4 the length of manubrium ( Fig. 10 View FIGURES 10–14 ). External distal corner chaeta as large as or shorter than medium-sized mesochaetae in chaetal strip ( Fig. 11 View FIGURES 10–14 ). Dental spine formula sensu Folsom (1913) as 4–8/3–5, 1, basal spines arranged in two rows ( Fig. 12 View FIGURES 10–14 ). Denticles almost evenly distributed on dental spines except for tips ( Fig. 13 View FIGURES 10–14 ). Mucro with 4–6 (average five, four specimens) intermediate teeth ( Fig. 14 View FIGURES 10–14 ).

Etymology. Named after the type locality: Gyirong Valley.

Habitat. In leaf litter, rotten woods and live mosses in a coniferous and broad-leaved mixed forest; also under a wood board beside a cottage in a village.

Remarks. Within Tomocerus (Ocreatomurus) , T. (O.) gyirongensis sp. nov. belongs to a species group with only one large distal dental spine. This group currently contains T. (O.) spinulus Chen & Christiansen, 1998 , T. (O.) leyensis Yu & Deharveng, 2018 , T. (O.) pseudospinulus Gong, Qin & Yu, 2018 and T. (O.) paraspinulus Gong, Qin & Yu, 2018 . Among them, T. (O.) gyirongensis sp. nov. is most similar to T. (O.) spinulus in the presence of pointed prominent chaetae on manubrium and dens, and the small size of denticles on dental spines, but the new species can be distinguished from the later by the following characters ( Table 1 View TABLE 1 ): first, T. (O.) gyirongensis sp. nov. has a larger number of tibiotarsal strong inner chaetae than T. (O.) spinulus ; second, T. (O.) gyirongensis sp. nov. has 2 + 2 prominent chaetae on manubrium, while T. (O.) spinulus has only 1 + 1 of them (sensu Yu et al. 2018); third, in T. (O.) gyirongensis sp. nov. the proximal dental spines are arranged strictly in two rows, while in T. (O.) spinulus these spines are arranged in a single row. In addition to these major differences, the relative length of antennae in T. (O.) gyirongensis sp. nov. is approximately 20–40 % (average 30 %) longer than that in T. (O.) spinulus (sensu Yu et al. 2018). Likely due to its larger body size, T. (O.) gyirongensis sp. nov. also has more chaetae on the ventral tube, tenaculum, and dorsal chaetal strips of the manubrium.