Mesochorus (Mesochorus) semipunctatus, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 33-34

Mesochorus (Mesochorus) semipunctatus nov. sp.

( Figs 6B , 12D , 19E , 23N )

Holotype. (♀) C Vietnam: Ha Tinh, Vu Quang N.P., 66 m, N 18°19´47´´ E 105°26´28´´, 4.iii. –15.iv.2011, Mal. trap 9, C. v. Achterberg, RMNH´11 (Leiden).

Etymology. The species name refers to the partly reduced punctation of the face.

Description. ♀: Body length 3.6 mm. Length of fore wing 3.2 mm.

Head. Flagellum with 29 flagellomeres; 1 st flagellomere 7.7 × longer than wide and 1.6 × longer than 2 nd flagellomere, 0.9 × as long as eye; 2 nd flagellomere 4.8 × longer than wide; preapical flagellomere 2.2 × longer than wide. Temple moderately and roundly narrowed behind eye, dorsally 0.5 × as long as eye. OED 1.5 × and OOD 0.7 × ocellar diameter. Occipital carina complete medially. Frons punctate dorsally. Face ( Fig. 12D ) densely punctate centrally, with sparse to rather dense punctures laterally, without central longitudinal ridge, width 1.1 × combined length of face and clypeus and 1.1 × eye length; inner eye margins parallel. Subantennal transverse carina dipped medially. Malar space and ventral 0.2 of facial orbit striate. Malar space 0.9 × 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 . 1.6 × longer than high. Mesoscutum rather densely punctate, punctuation very superficial on lateral lobe. Scuto-scutellar groove smooth. Scutellum moderately convex, almost smooth, without lateral carina, not pointed apically. Mesopleuron with rather dense punctures fronto-dorsally and sparse but coarse punctures ventrally. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Metapleuron with fine sparse punctures. Submetapleural carina low. Propodeum ( Fig. 19E ) completely carinate. Area basalis trapezoid, about as long as wide. Area superomedia 1.7 × longer than wide and 0.9 × as long as area petiolaris; anterior transverse carina (costula) reaching 4/10 of its length. Area petiolaris 1.3 × longer than wide. Hind femur 5.5 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.5 × longer than 2 nd hind tarsomere; hind claw with 1 long basal tooth. Areolet shortly sessile frontally; vein 2m-cu in its middle. Vein 1cu-a postfurcal by 0.3× its length. Pterostigma narrow, c 3.5 × longer than wide. Hind wing with 4 distal hamuli. Nervellus of hind wing moderately reclivous.

Metasoma. 1 st tergite 2.8 × longer than wide. Postpetiolus with some punctures and fine rugae apically. 2 nd tergite 1.2 × longer than wide. Thyridium transverse-oval. Ovipositor sheath ( Fig.22N ) densely pilose basally, sparsely pilose apically, stick-shaped, 11.3 × longer than wide, 0.6 × as long as hind tibia and 1.2 × longer than hind metatarsus.

Color. Flagellum brown, two basal flagellomeres ochreous; scape and pedicel yellowish externally. Head reddish-yellow; face and frons medially chestnut-red. Stemmaticum and occiput dorsally blackish. Face, clypeus and gena yellowish or reddish-yellow. Palps, mandible except teeth and malar space cream-yellow. Mesosoma largely black; mesoscutum black, with two paramedian dark reddish stripes; scutellum with reddish spot apically; side of pronotum dorsally and ventrally with yellowish stripes; mesopleuron reddish-brown dorsally and brown ventrally, with yellowish spot fronto-dorsally. Metapleuron and propodeum black. 1 st tergite black, yellowish basally. 2 nd tergite black, with large triangular yellow spot in apical 0.4. 3 rd tergite black, with baso-median yellow spot in basal 0.4. Following tergites brown. Sternites from 3 rd on and hypopygium brown laterally, yellow medially. Ovipositor sheath brown. Fore and mid coxae and all trochanters pale yellow; legs otherwise yellowish; hind tibia creamyellow, blackish in basal 0.1 and apical 0.2; hind tarsus except yellow base of metatarsus blackish. Pterostigma yellow-hyaline, margins darker.

♁ 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 is characterized by its brownish face with reduced punctuation, mainly brown apical tergites with narrow pale hind margins, long basal tooth on hind claw, and coarse and rather dense punctuation of ventral mesopleuron.

Figures

FIGURE 6. Oriental Mesochorinae, habitus from lateral. A−Mesochorus semifuscus n. sp. HT, B−M. semipunctatus n. sp. HT, C−M. siamensis n. sp., D−M. stigmaticolor n. sp. HT, E−M. striatofacies n. sp. HT, F−M. sulaensis n. sp. HT.

FIGURE 12. Oriental Mesochorinae, face from frontal. A− Mesochorus sapaensis n. sp. HT, B−M. semifuscus n. sp. HT (♀), C−M. semifuscus n. sp. PT (♁), D−M. semipunctatus n. sp. HT, E−M. siamensis n. sp., F−M. stigmaticolor n. sp. HT, G−M. striatofacies n. sp. HT (♀), H−M. striatofacies n. sp. PT (♁).

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 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.

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.