Mesochorus (Stictopisthus) sabahensis, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 30-31

Mesochorus (Stictopisthus) sabahensis nov. sp.

( Figs 5E , 11H , 14E , 19B, 23K)

Holotype. (♀) Malaysia: SE Sabah, nr Danum Valley Field C, c. 150 m, WONO, Mal. trap 5, 26.x. –22.xi.1987, C. v. Achterberg, RMNH´87 (Leiden).

Paratypes: (♀) with similar label (Leiden); (#f) Malaysia: SE Sabah, nr Danum Valley Field C, c 150 m, WONO, Mal. trap 5, 26.v. –20.vi.1987, C. v. Achterberg & D. Kennedy, RMNH´87 (coll. Riedel) .

Etymology. The species name is derived from Sabah.

Description. ♀: Body length 3.5–3.6 mm. Fore wing 2.8–3.0 mm.

Head. Flagellum with 28–30 flagellomeres; 1 st flagellomere 5.5–5.6 × longer than wide and 1.7 × longer than 2 nd flagellomere, 0.6 × as long as eye; 2 nd flagellomere 3.4–3.6 × longer than wide; preapical flagellomere 2.0 × longer than wide. Occipital carina complete medially. Temple moderately and roundly narrowed behind eye, dorsally c 0.5 × as long as eye. OED 1.7–2.0 × and OOD 0.6–0.8 × ocellar diameter. Frons smooth, with microsculpture laterally and with fine median longitudinal ridge. Face ( Fig. 11H ) coarsely but partly sparsely punctate, width 1.0 × combined length of face and clypeus and 1.1 × eye length; inner eye margins slightly convergent ventrally. Subantennal transverse carina not dipped medially. Malar space, mandible and ventral 0.3 of facial orbit with fine striae. 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 . 1.7 × longer than high. Side of pronotum large smooth, with few very sparse punctures. Notaulus distinct in frontal 0.3 of mesoscutum. Mesoscutum ( Fig. 14E ) with rather dense punctures, shining. Mesopleuron densely and coarsely punctate, speculum smooth. Dorsal end of epicnemial carina reaching frontal margin of mesopleuron. Scuto-scutellar groove ( Fig. 14E ) rather large, c 2.5 × wider than long, with 8-10 fine longitudinal ridges. Scutellum rounded in profile, with fine sparse punctures. Propodeum ( Fig. 19B ) completely carinate except confluent area basalis and area superomedia. Area superomedia 1.7 × longer than wide and 1.2 × longer than area petiolaris, with some transverse rugae; anterior transverse carina (costula) reaching its middle. Area petiolaris 1.0 × as long as wide. Hind femur 3.3–3.6 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.7 × longer than 2 nd hind tarsomere; hind claw with c 3 basal tooth, distal teeth long. Areolet pointed frontally; vein 2mcu slightly proximad or in its middle. Vein 1cu-a postfurcal by 1.0–1.3 × its length. Postnervulus intercepted in or distad its middle. Pterostigma 2.9–3.3 × longer than wide. Hind wing with 4 distal hamuli. Nervellus of hind wing vertical.

Metasoma. 1 st tergite 2.6–2.8 × longer than wide. Postpetiolus with longitudinal rugae. 2 nd tergite 1.1 × wider than long. Thyridium comma-shaped. Ovipositor sheath ( Fig. 23K ) sparsely pilose, 6.8 × longer than wide, 0.5 × as long as hind tibia and 1.0 × as long as hind metatarsus, moderately bent upwards apically.

Color. Body mainly reddish. Flagellum ochreous basally, brownish distally. Palps, mandible except teeth, malar space, and wide facial orbit cream-yellow. 1 st tergite brownish, basally yellowish. 2 nd tergite yellow, with brown triangular anterolateral spots. 3 rd tergite apically and 4 th tergite basally with ± extended brown spots. Ovipositor sheath brown. Fore and mid coxae and trochanters cream-yellow, legs otherwise reddish-yellow; hind tibia not or slightly infuscate apically. Pterostigma yellowish-hyaline.

♁. Male unknown.

Taxonomical remark. Within the subgenus Stictopisthus , this new species is characterized by a somewhat reduced punctuation of face, very coarse punctuation of meso- and metapleuron, and confluent area basalis and area superomedia with some fine transverse rugae.

Figures

FIGURE 5. Oriental Mesochorinae, habitus from lateral. A−Mesochorus paratenebris n. sp. HT, B−M. pictiloides n. sp. HT, C−M. pterostigmator n. sp., D−M. rufator n. sp. HT, E−M. sabahensis n. sp. HT, F−M. sapaensis n. sp. HT.

FIGURE 11. Oriental Mesochorinae, face from frontal. A− Mesochorus nigrofemur n. sp. HT (♀), B−M. nigrofemur n. sp. PT (♁), C−M. nigromaculatus n. sp. HT, D−M. paratenebris n. sp. HT, E−M. pictiloides n. sp. HT, F−M. pterostigmator n. sp., G−M. rufator n. sp. HT, H−M. sabahensis 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 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 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.