Xenarcha (Xenarcha) pacifica subsp. brevisculpta Belokobylskij & Ku 2025, ssp. nov.
Creators: name: Belokobylskij, Sergey A.
name: Ku, Deokseo
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Braconidae
Xenarcha
Xenarcha pacifica
Xenarcha (xenarcha) pacifica (belokobylskij, 1998) ssp. brevisculpta belokobylskij &amp; ku

description: Xenarcha (Xenarcha) pacifica (Belokobylskij, 1998) ssp. brevisculpta Belokobylskij & Ku ssp. nov.
Fig. 7
Type material.
Holotype • female, South Korea, [GW], Taebaek-si, Mt. Taebaek, 13.VIII.1989 (Seungman Ryu) (NIBR). Paratypes • Same label as holotype. 5 females, 1 male (SMNE, ZISP) • same label, but 13.VIII.1989 (Wonyeong Choi), 1 female (SMNE).
Description.
Female. Body length 3.0– 3.5 mm; fore wing length 3.4–3.8 mm. Head width 1.8–1.9 × its medial length (dorsal view), ~ 1.2 × wider than mesoscutum. Temple distinctly and convex-curvedly narrowed behind eye. Transverse diameter of eye 1.2–1.3 × longer than temple (dorsal view). Ocelli small, arranged almost in equilateral triangle. POL 1.0–1.2 × Od, 0.3–0.4 × OOL. Eye oval, glabrous, 1.25–1.30 × as high as broad (lateral view). Malar space 0.4–0.5 × height of eye, 0.9–1.3 × basal width of mandible. Malar suture very fine. Face width 1.1–1.2 × height of face and clypeus combined, 1.0–1.1 × height of eye. Hypoclypeal depression circular, its width almost equal to distance from edge of depression to eye, ~ 0.4 × width of face. Head distinctly and almost linearly narrowed below eyes. Antenna rather slender, weakly setiform, 37–38 - segmented, ~ 1.3 × longer than body. First flagellar segment 3.5–3.8 × longer than its apical width, 1.2–1.3 × longer than second segment. Penultimate segment 2.3–2.6 × longer than wide, ~ 0.5 × as long as first segment, 0.8–0.9 × as long as apical segment; the latter acuminate apically and with short ‘ spine’.
Mesosoma 1.7–1.8 × longer than its height. Pronotum dorsally with distinct, deep and smooth round pit (pronope), without transverse pronotal carina. Mesoscutum distinctly and curvedly elevated above prothorax. Notauli complete, rather deep, but more shallow posteriorly, smooth. Prescutellar depression short, coarsely rugulose-crenulate, 0.25 × as long as scutellum. Scutellum without transverse furrow and smooth posteriorly. Precoxal sulcus completely absent. Wings. Fore wing 2.8–3.0 × longer than maximum width. Pterostigma narrow, 5.0–5.3 × its maximum width, 0.7–0.8 × as long as metacarp (1 - R 1). Radial vein (r) arising distinctly before middle of pterostigma, from its basal ~ 0.3. Second radial abscissa (3 - SR) 2.7–3.0 × longer than first abscissa (r) and forming very obtuse angle with it, 0.5–0.6 × as long as the straight third abscissa (SR 1), 1.6–1.8 × longer than first radiomedial vein (2 - SR). Recurrent vein (m-cu) weakly antefurcal. Second radiomedial (submarginal) cell not narrowed distally, its length 2.6–2.8 × maximum width, 1.7–1.9 × longer than brachial (subdiscal) cell. Brachial (subdiscal) cell distinctly widened distally. First abscissa of medial vein (1 - SR + M) sinuate. Distance (1 - CU 1) from nervulus (cu-a) to basal vein (1 - M) 1.2–1.3 × nervulus (cu-a) length. Parallel vein (CU 1 a) arising from posterior 0.4 of distal margin (3 - CU 1) of brachial (subdiscal) cell. In hind wing, first abscissa of mediocubital vein (M + CU) 1.0–1.1 × as long as second abscissa (1 - M). First abscissa of costal vein (C + SC + R) 0.6–0.7 × as long as second abscissa (1 - SC + R). Recurrent vein (m-cu) not long, mainly unsclerotised, infuscate basally, weakly antefurcal and weakly curved. Legs. Hind femur 5.5–5.6 × longer than wide. Inner spur of hind tibia ~ 0.2 × as long as hind basitarsus. Hind tarsus approximately as long as hind tibia. Hind basitarsus ~ 0.6 × as long as combined length of second to fifth segments. Second tarsal segment of hind leg 0.5–0.6 × as long as basitarsus, 1.5–1.7 × as long as fifth segment (without pretarsus).
Metasoma 1.0–1.1 × longer than head and mesosoma combined. First tergite comparatively slender, evenly and linearly widened from base to apex, with very weak spiracular tubercles, with distinct dorsal carinae fused in basal one-third by additional transverse carina. Length of first tergite 1.0–1.1 (rarely 1.15) × its anterior width, anterior width 2.0–2.3 × its posterior width. Second suture weak, shallow, weakly curved, smooth. Medial length of second tergite 0.8–0.9 × its anterior width, 1.6–1.7 × length of third tergite. Setose part of ovipositor sheath ~ 0.2 × as long as metasoma, usually as long as first tergite, 0.7–1.0 × as long as hind basitarsus, ~ 0.1 × as long as fore wing.
Sculpture and pubescence. Vertex, frons and temple smooth; face mainly densely granulate, smooth or almost smooth medially in upper 0.3. Mesoscutum mainly smooth, with striation in narrow area in medioposterior quarter; scutellum and mesopleuron smooth. Metapleuron mainly coarsely transverse striate with rugosity, almost smooth in anterior 0.3. Propodeum entirely or almost entirely coarsely rugose-reticulate, with distinct medial carina in basal 0.6–0.7; without delineated areas. Legs mainly smooth, but hind coxa almost entirely rugose-reticulate. First metasomal tergite entirely and densely curvedly striate, with dense and coarse reticulation between striae; second tergite finely striate in anterior 0.3–0.5, smooth on remaining posterior part; remaining tergites entirely smooth. Mesoscutum mainly glabrous, with short, sparse and semi-erect pale setae arranged along notauli and in medio-posterior area. Hind tibia dorsally with short, very dense and semi-erect pale setae.
Colour. Body mainly black; metasoma behind first tergite reddish brown or dark reddish brown. Antenna mainly dark brown or black, 2–3 basal segments faintly paler. Palpi pale yellow. Legs mainly yellow, hind tarsus faintly infuscate. Wings hyaline. Pterostigma brown.
Male. Body length 3.4 mm; fore wing length 3.2 mm. Antenna 36 - segmented. Pterostigma of fore wing additionally sclerotised, dark brown, 3.2 × its maximum width. Length of first tergite 1.4 × its anterior width. Second suture finely and shortly crenulate. Second tergite striate-rugulose in anterior 0.7, its medial length 0.9 × anterior width, 1.2 × length of third tergite. Otherwise similar to female.
Discussion.
This new subspecies is very similar to Xenarcha (Xenarcha) pacifica ssp. pacifica (Belokobylskij, 1998) (Fig. 8), but differs from later by having the second metasomal tergite striate-rugulose only in anterior 0.3–0.4 (entirely or basically striate-rugulose in X. pacifica ssp. pacifica).
Etymology.
Named from the combination of the Latin words “ brevis ” (= short) and “ sculpta ” (= sculptural) because its second tergite of metasoma is sculptured only in the basal 1 / 2.
Distribution.
Korean peninsula.
description: Published as part of Belokobylskij, Sergey A. & Ku, Deokseo, 2025, Genera Colastes Haliday, Colastinus Belokobylskij, and Xenarcha Foerster (Hymenoptera, Braconidae, Exothecinae) from the Korean Peninsula with a discussion on the Exothecinae genus and subgenus composition, pp. 141-183 in ZooKeys 1236 on pages 141-183, DOI: 10.3897/zookeys.1236.148928