Mesochorus (Mesochorus) sumaterae, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 38-39

Mesochorus (Mesochorus) sumaterae nov. sp.

( Figs 7A , 13C , 19I, 24E)

Holotype. (♀) Indonesia: N Sumatra, Ketanbe , c 400 m, near N.P. Gn. Leuser, Mal. trap, iv.1994, Y. v. Nierop, C. v. Achterberg, RMNH´95 (Leiden).

Description. ♀: Body length 3.2 mm. Fore wing 2.7 mm.

Head. Flagellum slender, with> 29 flagellomeres (tips broken off); 1 st flagellomere 7.7 × longer than wide and 1.5 × longer than 2 nd flagellomere, 0.8 × as long as eye; 2 nd flagellomere 5.0 × longer than wide. Temple strongly and roundly narrowed behind eye, dorsally c 0.4 × as long as eye. OED 1.5 × and OOD 0.6 × ocellar diameter. Occipital carina complete medially. Frons almost smooth. Face ( Fig. 13C ) rather densely punctate, without central longitudinal ridge, width 0.9 × combined length of face and clypeus and 1.0 × eye length; inner eye margins slightly divergent ventrally. Subantennal transverse carina slightly dipped medially. Malar space striate, 0.8 × as long as width of mandibular base. Mandible with two rather small equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.

Mesosoma . 1.7 × longer than high. Mesoscutum densely punctate. Scuto-scutellar groove 2.2 × wider than long, with some longitudinal but superficial striae. Scutellum moderately convex, almost smooth, without lateral carina, not pointed apically. Mesopleuron with dense punctures fronto-dorsally and dense punctures ventrally. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Metapleuron with fine dense setiferous punctures. Propodeum ( Fig. 19I ) completely carinate, except confluent area basalis and area superomedia. Area basalis trapezoid, about as long as wide. Area superomedia 2.4 × longer than wide and 1.3 × as long as area petiolaris; anterior transverse carina (costula) reaching at 6/10 of its length. Area petiolaris 1.2 × longer than wide. Hind femur 4.8 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.7 × longer than 2 nd hind tarsomere; hind claw without visible teeth. Areolet pointed frontally; vein 2m-cu in its middle. Vein 1cu-a shortly postfurcal by 0.2 × its length. Postnervulus intercepted basad its middle. Hind wing with 4 distal hamuli. Nervellus of hind wing slightly reclivous.

Metasoma. 1 st tergite 3.1 × longer than wide. Postpetiolus distinctly striate. 2 nd tergite about as long as wide. Thyridium comma-shaped. Ovipositor sheath ( Fig. 24E ) densely pilose, 9.7 × longer than wide, 0.5 × as long as hind tibia and 1.0 × as long as hind metatarsus, slightly narrowed in apical 0.2.

Color. Flagellum brown. Head reddish; palps, mandible except teeth, malar space and facial orbit creamyellow; scape, pedicel and basal flagellomere ochreous; stemmaticum black; occiput reddish-brown. Pronotum red, yellow ventrally. Mesoscutum black, diffusely dark reddish apically. Scutellum and propodeum red. Mesopleuron and metapleuron yellowish-red. 1 st tergite black, yellow basally. 2 nd tergite black, with triangular yellow spot in apical 0.4. 3 rd tergite brown, was baso-median yellow spot. 4 th to 5 th tergites reddish-brown, with yellowish bands apically. Following tergites yellow. Ovipositor sheath pale brownish. Fore and mid coxae and all trochanters cream-yellow. Fore and mid legs otherwise yellow. Hind coxa yellow, with brown spot laterally; hind femur reddish, with brown lateral stripe; hind tibia yellow, blackish in basal 0.2 and apical 0.3; hind tarsus blackish. Pterostigma brown.

♁ unknown.

Taxonomical remark. This new species belongs to the pectoralis group sensu Schwenke (1999), e. g. basal tergites black, mid tergites with pale color pattern, apical tergite ± darkened. It is characterized by: face with rather dense punctures, without median ridge; area basalis and area superomedia confluent; scuto-scutellar groove with superficial ridges; hind leg darkened; mesoscutum black; postpetiolus distinctly striate.

Figures

FIGURE 7. Oriental Mesochorinae, habitus from lateral.A−Mesochorus sumaterae n. sp. HT, B−M. templator n. sp. HT, C−M. tenebris n. sp., D−M. tonkinensis n. sp. HT, E−M. trani n. sp. HT, F−M. vietnamensis n. sp. HT.

FIGURE 13. Oriental Mesochorinae, face from frontal. A−Mesochorus sulaensis n. sp. HT (♁), B−M. sulaensis n. sp. PT (m#), C−M. sumaterae n. sp. HT, D−M. templator n. sp. HT, E−M. tenebris n. sp., F−M. tonkinensis n. sp. HT, G−M. trani n. sp. HT, H−M. vietnamensis n. sp. HT.

FIGURE 19. Oriental Mesochorinae, propodeum from dorsal. A−Mesochorus rufator n. sp. HT, B−M. sabahensis n. sp. HT, C−M. sapaensis n. sp. HT, D−M. semifuscus n. sp. PT, E−M. semipunctatus n. sp. HT, F−M. siamensis n. sp. HT, G−M. stigmaticolor n. sp. HT, H−M. striatofacies n. sp. PT (♁), I−M. sumaterae n. sp. HT.

FIGURE 24. Oriental Mesochorinae, ovipositor sheath from lateral. A−Mesochorus siamensis n. sp., B−M. stigmaticolor n. sp. HT, C−M. striatofacies n. sp. HT, D−M. sulaensis n. sp. HT, E−M. sumaterae n. sp. HT, F−M. templator n. sp. HT, G−M. tenebris n. sp., H−M.