Mesochorus (Mesochorus) controversus, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 10-11

Mesochorus (Mesochorus) controversus nov. sp.

( Figs 2A , 8G , 22E )

Holotype. (♀) NW Vietnam: Tonkin, Hoang Lien N. R. 10 km SW Sa Pa , c. 1550 m, 22–29.x.1999, Malaise traps, C. v. Achterberg, RMNH´99 (Leiden).

Etymology. The species name refers to the questionable differences to the closely related species.

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

Head. Flagellum with 29 flagellomeres; 1 st flagellomere 6.1 × longer than wide and 1.5 × longer than 2 nd flagellomere, 0.7 × as long as eye; 2 nd flagellomere 3.9 × longer than wide; preapical flagellomere 2.7 × longer than wide. Temple moderately and roundly narrowed behind eye, dorsally 0.6 × as long as eye. OED 2.0 × and OOD 0.7 × ocellar diameter. Occipital carina complete medially. Frons with microsculpture and rather dense coarse punctures laterally. Face ( Fig. 8G ) densely punctate, with median ridge, width 1.1 × combined length of face and clypeus and 1.1 × eye length; inner eye margins parallel. Subantennal transverse carina strong, dipped medially. Malar space, mandible and ventral 0.5 of facial orbit widely striate. Malar space 0.7 × 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 . 1.7× longer than high. Mesoscutum densely punctate. Scuto-scutellar groove smooth. Scutellum moderately convex, with fine sparse punctures, without lateral carina, not pointed apically. Mesopleuron with rather dense punctures fronto-dorsally, ventral part with rather dense punctures frontally and very sparse fine punctures posteriorly. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Metapleuron with sparse punctures. Submetapleural carina low. Propodeum completely carinate. Area basalis triangular, slightly longer than wide. Area superomedia 1.9 × longer than wide and 0.9 × as long as area petiolaris; anterior transverse carina (costula) reaching its middle. Area petiolaris 1.1 × longer than wide. Hind femur 4.6 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.6 × longer than 2 nd hind tarsomere; hind claw without visible teeth. Areolet pointed frontally; vein 2m-cu slightly proximad its middle. Vein 1cu-a postfurcal by 0.3 × its length. Postnervulus intercepted basad its middle. Pterostigma 3.5× longer than wide. Hind wing with 4 distal hamuli. Nervellus of hind wing vertical.

Metasoma. 1 st tergite 2.4 × longer than wide. Postpetiolus smooth. 2 nd tergite 1.1 × wider than long. Thyridium transverse-oval. Ovipositor sheath ( Fig. 22E ) slender, with sparse setae in apical 1/2, 11.5 × longer than wide, 0.7 × as long as hind tibia and 1.3 × as long as hind metatarsus, moderately narrowed in apical 0.3.

Color. Flagellum brown; scape and pedicel ochreous. Head reddish-yellow. Palps, mandible except teeth, malar space and facial orbit cream-yellow; frons medially and stemmaticum black; occiput dorsally brown. Mesoscutum black, with two paramedian reddish-brown stripes. Scutellum black, reddish laterally and apically. Propodeum reddish-yellow; area basalis, area externa and basal half of area dentipara black. Propleuron and pronotum ochreous; pronotum yellow ventrally. Hind edge of pronotum and tegulae cream-yellow; mesopleuron and metapleuron brown. 1 st tergite black, basally yellowish, with apical reddish spot. 2 nd tergite black, with triangular yellowish spot in apical 0.6. 3 rd tergite black, with rectangular yellow spot in basal 0.4. Following tergites brown dorsally, yellow laterally. Sternites yellow. Ovipositor sheath brown. Fore and mid legs cream-yellow. Hind coxa yellow, weakly brownish dorsally; hind femur yellow; hind tibia cream-yellow, black in basal 0.1 and apical 0.2; hind tarsus except yellow base of metatarsus brownish. Pterostigma brownish, pale proximally and distally.

♁ 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). This small species resembles several other Vietnamese Mesochorus species, such as M. flavopronotalis nov. sp., M. harlequinus nov. sp. and M. semipunctatus nov. sp. The separation of these species is not always definitive with the available material, because the structural and color differences might be due to intra-specific variability.

Figures

FIGURE 2. Oriental Mesochorinae, habitus from lateral. A−Mesochorus controversus n. sp. HT, B−M. diversidens n. sp. HT, C−M. flavator n. sp., D−M. flavopronotalis n. sp. HT, E−M. fuscomaculatus n. sp. HT, F−M. halmaherae 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 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.