Megastylus (Dicolus) mentouense 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 : 457-459

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

Figures 1–9

Material examined. Holotype, Male, CHINA: Mentougou , 1760 m, Beijing, 3 October 2008, Tao Wang (IT) . Paratype: 1 male, same data as holotype except 26 September 2008 .

Diagnosis. Anterior tentorial pit large, upper margin distinctly below a line connecting lower margins of eyes. Malar space approximately 1.5 × as long as basal width of mandible. Postocellar line 0.9 × as long as ocular-ocellar line.Antenna with 26 flagellomeres; flagellomeres with two sorts, distinctly longer and shorter setae. Prepropodeum ( Fig. 7 ) almost smooth, shiny, 0.33 × as long as total length of prepropodeum and propodeum. Propodeum ( Fig. 7 ) without transverse and lateromedian longitudinal carinae. Fore and mid coxae yellowish white. Mesopleuron ( Figs 1 , 6 ) and mesosternum brownish red.

Description. Male ( Fig. 1 ). Body length approximately 5.0 mm. Fore wing length 4.5 mm. Antenna length 5.0– 5.3 mm.

Head. Inner orbits slightly narrowed medially, scarcely concave near antennal sockets. Face ( Fig. 2 ) 1.3–1.4 × as wide as long, almost smooth, shiny; upper margin with median longitudinal tubercle; upper lateral between eye and antennal socket with weak longitudinal depression. Clypeal sulcus distinct. Anterior tentorial pit large, upper margin distinctly below a line connecting lower margins of eyes. Clypeus strongly convex, texture as face, 1.6 × as wide as long, median portion of apical margin almost truncate. Mandible ( Fig. 2 ) small, basal portion stout, strongly narrowed apically; with two different teeth. Malar space 1.5 × as long as basal width of mandible, slightly concave. Gena ( Figs 3, 4 ) smooth, shiny, evenly and strongly converging to occipital carina. Vertex and frons almost smooth, shiny. Stemmaticum distinctly convex. Postocellar line approximately 0.9 × as long as ocular-ocellar line. Antenna with 26 flagellomeres; flagellomeres with two sorts of setae, longer setae sparse, approximately as long as diameter of flagellomere; shorter setae dense, at most as long as 0.5 diameter of flagellomere; ratio of length from first to fifth flagellomeres: 10.5:6.4:5.8:5.5:5.2. Occipital carina complete, strong, joining hypostomal carina above base of mandible.

Mesosoma. Pronotum ( Figs 4 , 6 ) almost entirely smooth, shiny; anterolateral portion with indistinct fine punctures. Epomia distinct, almost reaching to posterior margin of pronotum. Mesoscutum ( Figs 5, 6 ) strongly convex, shiny, with fine leathery texture; notauli very weak anteriorly, vestige. Scutoscutellar groove smooth, shiny. Scutellum ( Fig. 9 ) relatively convex, with texture as mesoscutum, lateral carina almost complete. Postscutellum inverted triangular, almost entirely combined with scutellum. Mesopleuron ( Fig. 6 ) almost smooth, shiny, with sparse fine setae; lower portion slightly convex; upper end of epicnemial carina approximately reaching front edge of mesopleuron, and 0.85 height to subtegular ridge. Metapleuron distinctly elongated, anterior portion with dense irregular punctures, posterior sparsely punctate; juxtacoxal carina absent. Hind leg slender. Hind femur 9.5 × as long as its maximum width. Hind tibia 12.5 × as long as its maximum width, almost as long as hind tarsus. Ratio of length of hind tarsomeres from first to fifth: 9.5:5.3:3.5:2.1:2.4. Wings hyaline. Fore wing with vein 1cu-a interstitial. Areolet absent. Vein 2m-cu with one bulla. Postnervulus intercepted at middle. Hind wing vein M+CU distinctly arched posteriorly, 1-cu 1.9 × as long as cu-a, discoidella unpigmented. Prepropodeum ( Fig. 7 ) 0.33 × as long as total length of prepropodeum and propodeum, median portion smooth, shiny; sublateral with weak sculpture. Propodeum ( Fig. 7 ) evenly convex, shiny, without transverse and lateromedian longitudinal carinae, weakly roughened; irregular indistinct longitudinal wrinkles and brownish setae; lateromedian longitudinal carinae irregular; apicomedian portion smooth. Propodeal spiracle small, circular.

Metasoma. Tergites 1–2 ( Fig. 8 ) shagreened. Tergite 1 3.8–4.0 × as long as apical width, posterior half of postpetiole slightly widened; latero-median carina absent; anterior portions of dorso-lateral carinae weakly present; spiracle convex, located at anterior 0.36 of tergite 1. Tergites 2 and 3 slightly shagreened. Tergite 2 distinctly trapezoidal, 1.2–1.4 × as long as posterior width, posterior portion smooth. Thyridium small, weakly transverse, distance to anterior margin 0.8 × as long as transverse diameter. Tergites 3 and subsequent transverse, with gray setae. Posterior margin of tergite 6 weakly concave medially. Posteromedian portion of tergite 7 strongly concave. Paramere ( Fig. 1 ) triangular, strongly narrowed posteriorly.

Coloration ( Fig. 1 ). Black, except for following: Face, clypeus, lower half of gena, mandible except teeth, maxillary palpi, labial palpi, propleuron, lower portion of pronotum, tegula except center, fore and mid coxae and trochanters, lower profile of hind coxa, hind trochanter, anterior posterior portions of tergite 3 and basal portion of tergite 4 yellowish white.Apexes of scape and pedicel, brownish yellow. Mesopleuron except upper anterior portion, and mesosternum brownish red. Fore and mid femora and tibiae, tarsomeres 1–4 of fore tarsus and tarsomeres 1–2 of mid tarsus pale yellow. Dorsal profile of hind coxa irregularly yellowish red, with blackish spot. Hind femur except dorsal profile, basal 0.7–0.8 of tibia brownish yellow.

Distribution. CHINA: Beijing.

Etymology. The specific name is derived from the type locality.

Remarks. The new species is similar to M. (D.) elegans Rossem, 1983 , but can be distinguished easily from the preceding key.

Figures

FIGURES 1–4. Megastylus (Dicolus) mentouense Sheng & Li, sp. nov. Holotype. Male. 1 Habitus, lateral view 2 Head, anterior view 3 Head, dorsal view 4 Head and pronotum, lateral view.

FIGURES 5–9. Megastylus (Dicolus) mentouense Sheng & Li, sp. nov. Holotype. Male. 5 Mesoscutum and scutellum, dorsal view 6 Mesosoma, lateral view 7 Postscutellum, Prepropodeum and propodeum 8 Tergite 1, dorsal view 9 Tergites 2–3, dorsal view