Stenaoplus yakushimae, Riedel & Watanabe, 2025

Stenaoplus yakushimae sp. nov.

( Figs 40–43 View FIGURES 40–43 )

Holotype. ( ♀) [ Japan] Kagoshima Pref., Yakushima Isl., Malaise trap (Y3), 1200 m alt., 2. V. – 4. VI. 2007, T. Yamauchi et al. leg. ( Kanagawa).

Paratypes. ( ♀) [ Japan] Kagoshima Pref., Yakushima Isl. , Malaise trap (H2), 250 m alt., 8–28. VI. 2007, T. Yamauchi et al. leg.; ( ♂) Kagoshima Pref., Yakushima Isl. , Malaise trap (Y3), 1200 m alt., 25. VIII. – 22. IX. 2006, T. Yamauchi et al. leg. ( 1 ♀ 4 ♂♂) Kagoshima Pref., Yakushima Isl. , Malaise trap (Y3, 1200 m alt.), 22. VII. – 22. VIII. 2006, T. Yamauchi et al. leg.; ( ♂) Kagoshima Pref., Yakushima Isl. , Malaise trap (Y3), 1200 m alt., 2. V. – 4. VI. 2007, T. Yamauchi et al. leg.; ( ♂) Kagoshima Pref., Yakushima Isl. , Malaise trap (Y3), 1200 m alt., 28. VI. – 29. VII. 2007, T. Yamauchi et al. leg. ( Kanagawa and coll. Riedel) .

Etymology. The species name refers to the collection site, Yakushima Island.

Description. Female. Body length 9.5–10.0 mm.

Head. Flagellum with 34–36 flagellomeres, slender and slightly lanceolate; 1 st flagellomere 3.8–4.5× as long as wide, c 12 th flagellomere square, widest flagellomere 1.4× as wide as long. Temple short, distinctly and roundly narrowed behind eye. OED 1.0–1.3× and OOD 0.8–1.2× ocellar diameter. Frons shagreened, with sparse superficial punctures dorsally. Face densely punctate, with fine transverse rugae medially, finely shagreened, ± shining.Anterior tentorial pits large. Clypeus slightly convex, rather densely punctate; apical margin blunt and almost straight. Mandible long, rather slender; ventral tooth much smaller than dorsal tooth and moderately bent inwards (by 45°). MI 1.0–1.1. Gena rather densely punctate ventrally. Genal carina reaching hypostomal carina close to mandibular base, both carinae low.

Mesosoma . Notaulus shortly impressed at frontal margin of mesoscutum. Mesoscutum densely punctate and finely granulate, dull. Mesopleuron densely punctate, partly rugose-punctate posteriorly; speculum smooth. Metapleuron densely punctate, punctation sparser centrally; juxtacoxal carina present. Scutellum moderately and roundly raised medially, slightly wider than long, with dense punctures and complete lateral carina. Propodeum largely punctate or rugose-punctate, completely carinate, without apophysis; spiracle slit-shaped. Area basalis moderately bulging medially. Area superomedia large, horseshoe- or heart-shaped, slightly wider than long; costula reaching at 4/10 of its length. Hind coxa densely punctate, without scopa. Hind femur densely and superficially punctulate, 3.7–4.1× as long as wide. External surface of hind tibia densely pilose and with multiple fine spines. Claws simple. Areolet pentagonal, frontal distance between veins 2rs-m and 3rs-m 1.0–2.0× their width; vein 2m-cu reaching slightly distal to its middle. Vein 1cu-a postfurcal by 2.0× its width.

Metasoma. Oxypyygous. Postpetiole moderately widened, without latero-median carina, median field slightly elevated and with fine longitudinal rugae; lateral field punctate. Gastrocoelus impressed, with some rugae.Thyridium large, slightly oblique, 1.8–2.2× as wide as interval between thyridia. 2 nd to 4 th sternites with median folds. 2 nd tergite 1.0–1.1× as wide as long; 2 nd and 3 rd tergites densely rugose-punctate, dull; 2 nd tergite with fine striation between thyridia. Ovipositor sheath slender, widely reaching beyond metasomal apex (by length of 2 nd hind tarsomere).

Color . Black, with extensive ivory coloration. Flagellomeres 7–12/13 ivory dorsally. Palps, mandible except teeth, clypeus, face, gena and complete orbits, ventral spot of scape, frontal and upper margins of pronotum, long paramedian stripe of mesoscutum, subtegular ridge, epicnemium laterally and longitudinal band of ventral mesopleuron, upper division and posterior spot of metapleuron, prescutellar ridge, sides of scutellum and postscutellum, and area posteroexterna of propodeum ivory. Tergites black; 1 st to 3 rd tergite with ivory posterolateral spots (narrowly confluent medially on 1 st and 2 nd tergites); apical band on 6 th tergite and 7 th and 8 th tergites entirely ivory. Coxae black, usually with apical ivory spots. Fore and mid trochanters entirely and hind trochanter entirely or apically ivory. Fore and mid legs otherwise red to chestnut-red, its femora and tibiae ± yellowish frontally. Hind femur black; hind tibia black, reddish in basal 0.6–0.7; hind tarsus except red base of metatarsus black. Wings almost hyaline; pterostigma pale reddish-brown or brown.

Male. Body length 10.0–12.0 mm.

Structure. Flagellum with 32–35 flagellomeres, bristle-shaped; 1 st flagellomere 2.7–2.9× as long as wide, distal segments ± nodose. Tyloids on flagellomeres 7–14, linear to long-oval, maximally 0.6× as long as their flagellomeres. OED 1.0–1.2× ocellar diameter. MI 0.7. Mesopleuron densely punctate, speculum smooth. Metapleuron usually with sparse punctures in frontal half.Area superomedia heart-shaped, slightly wider than long. Hind femur 3.7–3.9× as long as wide. 2 nd tergite 0.9–1.1× as long as wide. Apical margin of hypopygium slightly rounded. Structure otherwise as described for the ♀.

Color . As described for the female, except: Flagellum black, sometimes basal flagellomeres ± reddish ventrally; flagellomeres 12/13–16/18 ivory dorsally. Ivory orbital stripe sometimes interrupted at vertex. Mesoscutum with anterolateral ivory spot, without paramedian stripe. 6 th tergite ivory apically; 7 th tergite, hypopygium and paramere entirely ivory. Hind tibia blackish, ± yellowish sub-basally.

Distribution. Japan (Yakushima Isl.).

Remarks. This species differs from Stenaoplus japonicus (Cameron, 1886) by its yellow scutellum and from Stenaoplus maculipes (Smith, 1874) by the ivory face. It also differs from both species by the rich ivory maculation of mesosoma and apical ivory bands on basal tergites.