Mesochorus (Stictopisthus) sulaensis, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), Zootaxa 5245 (1), pp. 1-72 : 37-38

Mesochorus (Stictopisthus) sulaensis nov. sp.

( Figs 6F , 13A , 24D)

Holotype. (♀) Indonesia: Sula Isl. , Mangole, near Buya, Mal. trap 14, c 490 m, 2–22.iii.1995, C.v. Achterberg & Y. Yasir, RMNH (Leiden).

Paratype. (♁) Indonesia: Sula Isl. , Mangole, near Buya, Mal. trap 15, c 490 m, 2–22.iii.1995, C.v. Achterberg & Y. Yasir, RMNH (Leiden) .

Etymology. The species name is derived from the island Sula where the specimens were collected.

Description. ♀: Body length 2.8 mm. Fore wing 2.5 mm.

Head. Flagellum with 24 flagellomeres; 1 st flagellomere 4.9 × longer than wide and 1.4 × longer than wide, 0.6 × as long as eye; 2 nd flagellomere 3.5 × longer than wide; preapical flagellomere 2.2 × longer than wide. Occipital carina complete. Temple moderately and roundly narrowed behind eye, dorsally c 0.5 × as long as eye, almost smooth. OED 1.8 × and OOD 1.0 × ocellar diameter. Frons almost smooth, unmodified. Subantennal transverse carina not dipped medially. Face ( Fig. 13A ) moderately convex, coarsely punctate, partly rugose-punctate centrally, width 1.0 × combined length of face and clypeus and 1.0 × eye length; inner eye margins parallel. Malar space and ventral gena with sparse punctures. Malar space 0.9 × as long as width of mandibular base, with deep sulcus between lower eye margin and clypeus. Mandible rather slender, with two equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.

Mesosoma . Slightly depressed, 1.8 × longer than high. Notaulus distinct in frontal 0.3 of mesoscutum. Mesoscutum with rather dense punctures, shining. Mesopleuron with few fine punctures fronto-dorsal, almost smooth ventrally, speculum smooth. Dorsal end of epicnemial carina reaching frontal margin of mesopleuron. Metapleuron with fine very sparse punctures, juxtacoxal carina present. Scuto-scutellar groove 3.2 × wider than long, with c 4 longitudinal ridges. Scutellum rounded in profile, with fine sparse punctures, not carinate or pointed. Area basalis rectangular, 1.5 × longer than wide. Area superomedia 2.1 × longer than wide and 1.5 × longer than area petiolaris, smooth; anterior transverse carina (costula) reaching its middle. Area petiolaris wider than long. Hind femur 3.1 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.8 × longer than 2 nd hind tarsomere; hind claw without visible teeth. Areolet pointed frontally; vein 2m-cu in its middle. Vein 1cu-a postfurcal by 0.3 × its length. Postnervulus intercepted slightly distad its middle. Pterostigma 2.8 × longer than wide. Hind wing with 4 distal hamuli. Nervellus of hind wing vertical.

Metasoma. 1 st tergite 2.6 × longer than wide. Postpetiolus with some punctures, mainly smooth. 2 nd tergite 1.2 × wider than long. Thyridium comma-shaped. Ovipositor sheath ( Fig. 24D ) with sparse setae, 6.0 × longer than wide, 0.5 × as long as hind tibia and 1.0 × as long as hind metatarsus, slightly bent upwards apically.

Color. Head blackish; Palps cream-yellow. Mandible except teeth, clypeus, face and frontal orbit reddish; facial orbit narrowly reddish-yellow. Scape and pedicel yellowish; flagellum brownish, two basal flagellomeres ochreous. Mesoscutum and scutellum reddish-brown; propodeum and metapleuron brown; pronotum yellowish-red; mesopleuron red; tegula yellow. 1 st tergite black, its sternite dark reddish. 2 nd tergite brown, with narrow yellowish band in apical 0.2. 3 rd tergite brown, with narrow yellow band in basal 0.1. Following tergites and ovipositor sheath brownish. Fore and mid coxae and all trochanters cream-yellow; fore and mid legs otherwise yellow; hind coxa ochreous; hind femur brownish; hind tibia ochreous internally, yellow externally, narrowly brown basally and apically; hind tarsus ochreous. Pterostigma brown, paler proximally and distally.

♁: Body length 3.2 mm. Fore wing 2.4 mm.

Head. Flagellum with> 23 flagellomeres (tips broken off); 1 st flagellomere 6.5 × longer than wide and 0.6 × as long as eye; 2 nd flagellomere 5.0 × longer than wide. Occipital carina complete. Temple moderately and roundly narrowed behind eye, dorsally c 0.5 × as long as eye, almost smooth. OED 1.6 × and OOD 0.6 × ocellar diameter. Frons almost smooth, with fine longitudinal median ridge below anterior ocellus. Face moderately convex, coarsely punctate, width 1.0 × combined length of face and clypeus and 0.9 × eye length; inner eye margins parallel. Malar space 0.6 × as long as width of mandibular base, with deep sulcus between lower eye margin and clypeus. Mandible with two equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.

Mesosoma . 1.7 × longer than high. Mesoscutum with rather dense punctures, shining. Mesopleuron with few fine punctures fronto-dorsal and fine very sparse punctures ventrally, speculum smooth. Metapleuron with fine very sparse punctures, juxtacoxal carina indicated by some irregular rugae. Scuto-scutellar groove with c 4 longitudinal ridges. Hind femur 3.6 × longer than wide; hind metatarsus 0.6 × as long as hind tibia; hind claw without visible teeth. Areolet pointed frontally; vein 2m-cu in its middle. Vein 1cu-a postfurcal by 0.3 × its length. Postnervulus intercepted in its middle. Hind wing with 4 distal hamuli. Nervellus of hind wing vertical.

Metasoma. 1 st tergite 2.7 × longer than wide. Postpetiolus with some short rugae. 2 nd tergite 1.5 × wider than long. Paramere long, 1.2 × as long as hind metatarsus, slightly clubbed apically.

Color. Head blackish; palps cream-yellow.Mandible except teeth, clypeus and face reddish; facial orbit narrowly, scape and pedicel ventrally yellow. Flagellum brown. Mesoscutum, scutellum, pronotum and mesopleuron reddishbrown; propodeum and metapleuron black; tegula yellow. 1 st tergite black. 2 nd tergite black, with narrow yellowish band in apical 0.2. Following tergites brownish. Fore and mid coxae and all trochanters cream-yellow; fore and mid legs otherwise yellow; hind coxa brownish-red; hind femur brownish, paler basally; hind tibia ochreous internally, yellow externally, brown in basal 0.1 and apical 0.2; hind tarsus black. Pterostigma brown.

Taxonomical remark. This species belongs to the subgenus Stictopisthus and is characterized by its dark body color and the presence of a ± distinct juxtacoxal carina.

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 13. Oriental Mesochorinae, face from frontal. A−Mesochorus sulaensis n. sp. HT (♁), B−M. sulaensis n. sp. PT (m#), C−M. sumaterae n. sp. HT, D−M. templator n. sp. HT, E−M. tenebris n. sp., F−M. tonkinensis n. sp. HT, G−M. trani n. sp. HT, H−M. vietnamensis n. sp. HT.

FIGURE 24. Oriental Mesochorinae, ovipositor sheath from lateral. A−Mesochorus siamensis n. sp., B−M. stigmaticolor n. sp. HT, C−M. striatofacies n. sp. HT, D−M. sulaensis n. sp. HT, E−M. sumaterae n. sp. HT, F−M. templator n. sp. HT, G−M. tenebris n. sp., H−M.