Mesochorus (Mesochorus) paratenebris, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 26-27

Mesochorus (Mesochorus) paratenebris nov. sp.

( Figs 5A , 11D , 23G )

Holotype. (♀) NW Vietnam: Tonkin, Hoang Lien N. R., 15 km W Sa Pa , c. 1900 m, 15–21.x.1999, Malaise traps, C. v. Achterberg, RMNH´99 (Leiden).

Paratype. (♀) similar label (Leiden).

Etymology. The species name refers to the color pattern which is similar to Mesochorus tenebris .

Description. ♀: Body length 3.1–3.5 mm. Length of fore wing 3.0– 3.2 mm.

Head. Flagellum with 27–29 flagellomeres; 1 st flagellomere 6.8–7.7 × longer than wide and 1.6 × longer than 2 nd flagellomere, 0.8 × as long as eye; 2 nd flagellomere 3.8–4.1 × longer than wide; preapical flagellomere 2.2–2.5 × longer than wide. Temple moderately and roundly narrowed behind eye, dorsally 0.6–0.7 × as long as eye. OED 1.5–1.8 × and OOD 1.0 × ocellar diameter. Occipital carina complete medially. Frons densely punctate and with fine transverse aciculation laterally. Face ( Fig. 11D ) densely punctate, without median longitudinal ridge, width 1.0–1.1 × combined length of face and clypeus and 1.0 × eye length; inner eye margins parallel. Subantennal transverse carina dipped medially. Malar space and ventral 0.3 of facial orbit striate. Malar space 0.9–1.0 × as long as width of mandibular base. Mandible with two equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.

Mesosoma . Rather stout, 1.5 × longer than high. Mesoscutum densely punctate. Scuto-scutellar groove smooth. Scutellum moderately convex, finely punctate, without lateral carina, not pointed apically. Mesopleuron with dense punctures fronto-dorsally and very sparse fine punctures ventrally. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Metapleuron with fine sparse punctures. Submetapleural carina low. Propodeum completely carinate. Area basalis trapezoid or triangular, c 1.5 × longer than wide. Area superomedia 1.3–1.6 × longer than wide and 0.6–0.9 × as long as area petiolaris; anterior transverse carina (costula) reaching the 3/10-4/10 of its length. Area petiolaris 1.0–1.2 × longer than wide. Hind femur 4.6–5.3 × longer than wide; hind metatarsus short, 0.4 × as long as hind tibia and 2.5 × longer than 2 nd hind tarsomere; hind claw without visible teeth. Areolet pointed frontally; vein 2m-cu in its middle. Vein 1cu-a interstitial or slightly postfurcal by 0.1 × its length. Postnervulus intercepted basad its middle. Pterostigma wide, 2.8–2.9 × longer than wide. Hind wing with 4 distal hamuli. Nervellus of hind wing slightly reclivous.

Metasoma. 1 st tergite 2.5–2.8 × longer than wide. Postpetiolus smooth. 2 nd tergite 1.5 × wider than long. Thyridium comma-shaped. Ovipositor sheath ( Fig. 23G ) densely pilose in basal half, with sparse setae apically, 10.4–11.8 × longer than wide, 0.6 × as long as hind tibia and 1.4–1.5 × longer than hind metatarsus, stick-shaped.

Color. Scape, pedicel and basal flagellum ochreous, distal flagellomeres brownish to black. Face, clypeus and orbits reddish-yellow. Palps, mandible except teeth and malar space cream-yellow. Frons medially, stemmaticum and occiput largely brown. Mesosoma brown; ventral margin of pronotum narrowly yellow (in paratype side of pronotum entirely yellow); hind edge of pronotum and tegula cream-yellow; mesoscutum brown, with H-shaped central red or reddish-brown spot; scutellum brown or red and with brown basal spot. 1 st tergite black, pale yellow basally. 2 nd tergite black, with pale yellow band in apical 0.2. 3 rd tergite black, with pale yellow band in basal 0.1. Following tergites black. 3 rd to 6 th sternites with lateral brownish spots. Ovipositor sheath brown. Fore and mid coxae and all trochanters cream-yellow; fore and mid legs otherwise pale yellow. Hind coxa reddish, with brown dorsal spot or entirely brownish. Hind femur yellow; hind tibia yellow, brown basally and in apical 0.2. Hind tarsus except ochreous metatarsus brownish. Pterostigma whitish-hyaline.

♁ unknown.

Taxonomical remark. With its sessile areolet, postfurcal vein 1cu-a, stick-shaped ovipositor and short area superomedia, this species belongs to the dispar group sensu Schwenke (1999).

It largely resembles M. tenebris nov. sp. and differs by shorter basal flagellomeres and hind metatarsus, and wider pterostigma. Hind coxa mainly brown. Hind tibia without brownish subbasal spot.

Figures

FIGURE 5. Oriental Mesochorinae, habitus from lateral. A−Mesochorus paratenebris n. sp. HT, B−M. pictiloides n. sp. HT, C−M. pterostigmator n. sp., D−M. rufator n. sp. HT, E−M. sabahensis n. sp. HT, F−M. sapaensis n. sp. HT.

FIGURE 11. Oriental Mesochorinae, face from frontal. A− Mesochorus nigrofemur n. sp. HT (♀), B−M. nigrofemur n. sp. PT (♁), C−M. nigromaculatus n. sp. HT, D−M. paratenebris n. sp. HT, E−M. pictiloides n. sp. HT, F−M. pterostigmator n. sp., G−M. rufator n. sp. HT, H−M. sabahensis n. sp. HT.

FIGURE 23. Oriental Mesochorinae, ovipositor sheath from lateral.A−Mesochorus longivalvator n. sp. HT, B−M. malaysiacus n. sp. HT, C−M. malucutus n. sp. HT, D−M. nigripleuris n. sp., E−M. nigrofemur n. sp. HT (♀), F−M. nigromaculatus n. sp. HT, G−M. paratenebris n. sp. HT, H−M. pictiloides n. sp. HT, I−M. pterostigmator n. sp., J−M. rufator n. sp. HT, K−M. sabahensis n. sp. HT, L−M. sapaensis n. sp. HT, M−M. semifuscus n. sp. HT, N−M. semipunctatus n. sp. HT.