Megastylus (Dicolus) flavicornis Sheng & Li, 2022

Zhang, Shu-Jie, Zhou, Qing, Li, Tao & Sheng, Mao-Ling, 2022, The genus Megastylus Schiødte (Hymenoptera, Ichneumonidae, Orthocentrinae) in China with a key to the species of China and Oriental Region, Zootaxa 5091 (3), pp. 455-466 : 459-462

Megastylus (Dicolus) flavicornis Sheng & Li , sp. nov.

Figures 10–20

Material examined. Holotype, Male, CHINA: Songluo, 1030 m, Shennongjia National Natural Reserve , Hubei, 4 August 2012, Xiao-Yan Liu.

Diagnosis. Prepropodeum ( Fig. 17 ) 0.2 × as long as total length of prepropodeum and propodeum, with lateral outward arched carina. Propodeum with two strong transverse carinae. Tergite 1 and anterior half of tergite 2 with irregular longitudinal wrinkles. Posterior portion of tergite 1 from spiracle to posterior margin evenly widened posteriorly. Median rectangular spot of mesoscutum, posteromedian triangular spot of mesosternum and parameres yellowish white.

Description. Male ( Fig. 10 ). Body length 5.0 mm. Fore wing length 3.9 mm. Antenna length approximately 5.5 mm.

Head. Inner orbits slightly emarginate opposite antennal socket. Face ( Fig. 11 ) 1.3 × as wide as long, most flat, shiny; with fine indistinct; upper median portion slightly concave longitudinally, with a weak small tubercle. Upper margin of anterior tentorial pit distinctly above a line connecting lower margins of eyes. Clypeus strongly convex, texture as face, 1.5 × as wide as long, apical margin evenly arched forward. Mandible small, strongly narrowed apically. Subocular sulcus distinct. Malar space 1.5 × as long as basal width of mandible, posterior portion smooth. Gena and vertex ( Figs 12, 13 ) slightly shagreened, shiny, strongly converging to occipital carina. Stemmaticum distinctly convex. Postocellar line approximately 0.8 × as long as ocular-ocellar line. Frons evenly concave, smooth, shiny.Antenna with 26 flagellomeres. Ratio of length from first to fifth flagellomeres: 14.5:9.0:8.3:7.5:7.2. Occipital carina complete, strong, dorsal portion evenly distinctly arched.

Mesosoma. Pronotum ( Figs 13, 15 ) smooth, almost shiny; dorsoanterior margin with distinct emarginate. Epomia indistinct. Mesoscutum ( Fig. 14 ) slightly shagreened; with median pentagonal flat, smooth, shiny; notauli distinct, reaching beyond middle of mesoscutum. Scutoscutellar groove smooth, shiny, relatively shallow and wide. Scutellum with texture as mesoscutum, lateral carina almost reaching to apex of scutellum. Postscutellum ( Fig. 17 ) small, cone-shaped convex. Mesopleuron ( Fig. 15 ) with texture as pronotum, lower portion distinctly convex; upper end of epicnemial carina distance from front edge of mesopleuron, and 0.8 height to subtegular ridge. Mesosternum ( Fig. 16 ) with sparse fine punctures; medial sternal groove shallow, strongly widened posteriorly. Metapleuron weakly evenly convex, with fine obscure punctures. Hind leg slender. Hind femur 6.6 × as long as its maximum width. Hind tibia 10.6 × as long as its maximum width; longer spur 0.4 × as long as first tarsomere. Hind tarsus almost as long as hind tibia. Ratio of length of hind tarsomeres from first to fifth: 14.5:7.2:5.0:3.2:4.2; lower profile of first tarsomere with dense distinct setae. Claw simple. Wings ( Fig. 10 ) hyaline. Fore wing with vein 1cu-a almost interstitial. Areolet absent. Vein 2m-cu with one bulla. Postnervulus intercepted at lower 0.4. Hind wing vein M+CU distinctly arched posteriorly, 1-cu 2.3 × as long as cu-a, discoidella unpigmented. Prepropodeum ( Fig. 17 ) smooth, shiny, 0.2 × as long as total length of prepropodeum and propodeum, lateral with outward arched carina. Propodeum ( Fig. 17 ) with two strong transverse carinae, lateromedian longitudinal carinae absent; basal area between basal margin and anterior transverse carina granular, with fine obscure punctures, between two transverse carinae obscure sculpture, posterior area finely granular. Propodeal spiracle small, circular, distance to pleural carina less than its diameter.

Metasoma. Tergite 1 ( Fig. 18 ) 3.0 × as long as apical width, with irregular longitudinal wrinkles, posterior portion from spiracle to posterior margin evenly widened posteriorly, basal portion parallel laterally; latero-median carina absent; dorso-lateral carinae indistinct; spiracle convex, located at anterior 0.4 of tergite 1. Tergite 2 ( Fig. 19 ) 1.1 × as long as apical width, strongly widened posteriorly, anterior half with distinct longitudinal wrinkles; posterior half finely shagreened. Thyridium elliptic, closed to anterior margin. Third tergite shagreened, strongly convergent posteriorly, 0.8 × as long as anterior width. Paramere ( Fig. 20 ) short, evenly narrowed posteriorly.

Coloration ( Fig. 10 ). Mainly with three colorations. The followings are with white coloration: Face, maxillary palpi, labial palpi, lower portions of genae, lateral sides of frons, propleuron, pronotum, tegula, lower posterior portion of mesopleuron, fore and mid coxae. Black portions: upper portions of genae, vertex, frons medially, postscutellum, propodeum, metapleuron, tergites 1–2 and 6–7 almost entirely. Antenna brownish black. Clypeus and mandible yellowish brown. Scape, pedicel, basal ventral profile of flagellomeres, mesosoma except yellowish white median rectangular spot of mesoscutum, legs except apex of hind tibia, pterostigma and veins predominantly reddish brown. Posteromedian triangular spot of mesosternum, tergites 3–4 predominantly and parameres yellowish white.

Distribution. CHINA: Hubei.

Etymology. The specific name is derived from the triangular spot of posteromedian portion of mesosternum.

Remarks. The new species is similar to M. (D.) pectoralis ( Förster, 1871) , but can be distinguished from the latter by the following combination of characters: hind tibia normal, entire length almost same wide; propodeum with two strong transverse carinae; tergite 2 with distinct longitudinal wrinkles. M. (D.) pectoralis : subapical portion of hind tibia distinctly narrowed; propodeum with one transverse carina; tergite 2 without wrinkles.

Figures

FIGURE 10. Megastylus (Dicolus) flavicornis Sheng & Li, sp. nov. Holotype. Male. Habitus, dorsal view.

FIGURES 11–16. Megastylus (Dicolus) flavicornis Sheng & Li, sp. nov. Holotype. Male. 11 Head, anterior view 12 Head, dorsal view 13 Head and pronotum, lateral view 14 Mesoscutum and scutellum, dorsal view. 15 Mesosoma, lateral view 16 Mesosoma, ventral view.

FIGURES 17–20. Megastylus (Dicolus) flavicornis Sheng & Li, sp. nov. Holotype. Male. 17 Postscutellum, Prepropodeum and propodeum 18 Tergite 1, dorsal view 19 Tergites 2–3, dorsal view 20 Male. Posterior portion of metasoma, lateral view.