Mesochorus (Mesochorus) cariniscuta, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 9-10

Mesochorus (Mesochorus) cariniscuta nov. sp.

( Figs 1F , 8F , 14B , 17E, 22D)

Holotype. (♀) Indonesia: Sula Isl. , Mangole, near Buya, 2–22.iii.1996, C. v. Achterberg & Y. Yasir, RMNH (Leiden).

Etymology. The species name refers to the characteristic transverse carina of the scutellum.

Description. ♀: Body length 5.0 mm.

Head. Flagellum slender and long, with 35 flagellomeres; 1 st flagellomere 5.6 × longer than wide and 1.7 × longer than 2 nd flagellomere, 0.6 × as long as eye; 2 nd flagellomere 3.3 × longer than wide; preapical flagellomere 2.8 × longer than wide. Temple strongly and roundly narrowed behind eye, dorsally c 0.5 × as long as eye. OED 0.8 × and OOD 0.8 × ocellar diameter. Frons with microsculpture, not punctate. Face ( Fig. 8F ) coarsely punctate, without central longitudinal ridge, width 1.1 × combined length of face and clypeus and 1.0 × eye length; inner eye margins parallel. Subantennal transverse carina dipped medially. Malar space with fine striae. Malar space 0.6 × 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 . Stout, 1.5 × longer than high. Mesoscutum coarsely and densely punctate centrally, with sparse punctures laterally, shining. Frontal margin of scuto-scutellar groove rounded. Scutellum ( Fig. 14B ) weakly convex, without lateral carina, but with apical transverse carina, not pointed apically. Mesopleuron and metapleuron with very sparse setiferous punctures, speculum smooth. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Juxtacoxal carina partly present at basal and apical margins of metapleuron. Submetapleural carina strongly lamelliform frontally. Propodeum ( Fig. 17E ) short and strongly declining towards apex, completely carinate. Area basalis triangular, slightly longer than wide. Area superomedia short, 1.2 × longer than wide and 0.7 × as long as area petiolaris; anterior transverse carina (costula) reaching its middle. Area petiolaris very large, 1.4 × longer than wide and 0.6× as long as propodeum. Hind femur 4.4 × longer than wide; hind metatarsus 0.4 × as long as hind tibia and 2.4 × longer than 2 nd hind tarsomere; hind claw with 3 basal teeth.Areolet pointed frontally, slightly oblique; vein 2m-cu proximad its middle. Vein 1cu-a antefurcal by 1.0 × its width. Postnervulus intercepted basad its middle. Hind wing with 5 distal hamuli. Nervellus of hind wing vertical.

Metasoma. 1 st tergite 2.5 × longer than wide. Postpetiolus smooth. 2 nd tergite 1.4 × wider than long. Thyridium roundish. Ovipositor sheath ( Fig. 22D ) densely pilose, 6.0 × longer than wide, 0.5 × as long as hind tibia and 1.1 × longer than hind metatarsus, moderately narrowed in apical 0.4.

Color. Body mainly yellow. Flagellum brownish, scape and pedicel yellow, two basal flagellomeres ochreous. Palps, clypeus, mandible except teeth, malar space and facial orbit cream-yellow. 2 nd tergite with narrow ivory hind margin. Fore and mid coxae and trochanters cream-yellow, legs otherwise yellow; hind tibia brownish in apical 0.1 (0.5× tibial width); hind tarsus ochreous. Pterostigma brown.

♁ unknown.

Taxonomical remark. This species belongs to the fulvus group sensu Schwenke (1999), e. g. body entirely reddish, without dark spots. It is characterized by a stout mesosoma, transversely carinate scutellum, partly present juxtacoxal carina and presence of 5 distal hamuli on hind wing.

The carination of propodeum (e. g. very short area superomedia and long area petiolaris) resembles the Taiwanese M. takizawai Kusigemati, 1985 , but M. cariniscuta nov. sp. differs by the entire red mesosoma without brown stripes, and the transversely carinate scutellum.

Figures

FIGURE 1. Oriental Mesochorinae, habitus from lateral. A−Orientochorus tonkinensis n. sp. HT, B−Astiphromma bicoloratus n. sp. HT, C−Mesochorus achterbergi n. sp. HT, D−M. annamensis n. sp. HT, E−M. brevipunctatus n. sp. HT, F−M. cariniscuta n. sp. HT.

FIGURE 8. Oriental Mesochorinae, face from frontal. A−Orientochorus tonkinensis n. sp. holotype (HT), B−Astiphromma bicoloratus n. sp. HT, C−Mesochorus achterbergi n. sp. HT, D−M. annamensis n. sp. HT, E−M. brevipunctatus n. sp. HT, F−M. cariniscuta n. sp. HT, G−M. controversus n. sp. HT, H−M. diversidens n. sp. HT (♀).

FIGURE 14. Oriental Mesochorinae, mesoscutum from dorsal.A−Mesochorus achterbergi n. sp. HT (♁), B−M. carinisctua n. sp. HT with carinate scutellum, C−M. flavopronotalis n. sp. HT, D−M. kinabaluensis n. sp. HT, E−M. sabahensis n. sp., F−M. malucutus n. sp. HT.

FIGURE 17. Oriental Mesochorinae, propodeum from dorsal. A−Orientochorus tonkinensis n. sp. HT, B−Astiphromma bicoloratus n. sp. HT, C−Mesochorus annamensis n. sp. HT, D−M. brevipunctatus n. sp. HT, E−M. cariniscuta n. sp. HT, F−M. diversidens n. sp. HT (♀), G−M. fuscomaculatus n. sp. HT, H−M. halmaherae n. sp. HT, I−M. harlequinus n.sp. HT.

FIGURE 22. Oriental Mesochorinae, ovipositor sheath from lateral. A−Orientochorus tonkinensis n. sp. holotype (HT), B−Mesochorus annamensis n. sp. HT, C−M. brevipunctatus n. sp. HT, D−M. cariniscuta n. sp. HT, E−M. controversus n. sp. HT, F−M. diversidens n. sp. HT, G−M. flavator n. sp. HT, H−M. flavopronotalis n. sp. HT, I−M. fuscomaculatus n. sp. HT, J−M. halmaherae n. sp. HT, K−M. harlequinus n.sp. HT, L−M. kinabaluensis n. sp. HT, M−M. lamdongensis n. sp. HT, N−M. longimurus n. sp. HT.