Mesochorus (Mesochorus) sumaterae Riedel 2023, nov. sp.

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.