Mesochorus (Stictopisthus) flavator Riedel 2023, nov. sp.
Creators: name: Riedel, Matthias
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Mesochorus
Mesochorus flavator

description: Mesochorus (Stictopisthus) flavator nov. sp.
(Figs 2C, 9B, 22G)
Holotype. (♀) Indonesia: Sula Isl., Mangole, near Buya, Mal. trap 16, c. 500 m, 2–22.iii.1996, C. v. Achterberg & Y. Yasir, RMNH (Leiden).
Etymology. The name refers to the mainly yellow (Latin: “flavus”) coloration of this species.
Description. ♀: Body length 3.5 mm. Fore wing 3.0 mm.
Head. Flagellum with 29 flagellomeres; 1 st flagellomere 4.5 × longer than wide and 1.4 × longer than 2 nd flagellomere, 0.5 × as long as eye; 2 nd flagellomere 2.9 × longer than wide; preapical flagellomere c 1.5 × longer than wide. Occipital carina complete medially. Temple moderately and roundly narrowed behind eye, dorsally c 0.5 × as long as eye. OED 2.2 × and OOD 0.5 × ocellar diameter. Frons with transverse microsculpture laterally, with weak longitudinal ridge below anterior ocellus and with two fine paramedian ridges between antennal sockets. Face (Fig. 9B) coarsely punctate, very wide, width 1.3 × combined length of face and clypeus and 1.2 × eye length; inner eye margins parallel. Subantennal transverse carina not dipped medially. Malar space and ventral 0.2 of facial orbit with fine striae. Malar space 0.9 × as long as width of mandibular base. Mandible rather slender, with two equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.
Mesosoma. Slightly depressed, 1.9 × longer than high. Side of pronotum largely smooth. Notaulus distinct in frontal 0.3 of mesoscutum. Mesoscutum with rather dense punctures apico-medially, shining. Mesopleuron with dense punctures fronto-dorsally and with rather dense punctures ventrally, speculum smooth. Dorsal end of epicnemial carina reaching frontal margin of mesopleuron Metapleuron densely punctate; juxtacoxal carina partly present. Scuto-scutellar groove narrow, c 4.0 × wider than long, smooth and without distinct ridges. Scutellum rounded in profile, with fine sparse punctures. Area basalis trapezoid, 1.5 × wider than long. Area superomedia wide, 1.2 × longer than wide and 0.85 × as long as area petiolaris, smooth; anterior transverse carina (costula) reaching its middle.Area petiolaris 1.2 × longer than wide. Hind femur 2.9 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 3.2 × longer than 2 nd hind tarsomere; hind claw without visible teeth. Areolet shortly sessile frontally, oblique; vein 2m-cu slightly proximad its middle. Vein 1cu-a postfurcal by 1.0× its length. Postnervulus intercepted in its middle. Pterostigma 2.9 × longer than wide. Distal part of RA (metacarp) long, about as long as width of pterostigma. Hind wing with 4 distal hamuli. Nervellus of hind wing vertical.
Metasoma. 1 st tergite stout, 2.2 × longer than wide. Postpetiolus with longitudinal rugae. 2 nd tergite 1.1 × wider than long. Thyridium comma-shaped. Ovipositor sheath (Fig. 22G) with sparse setae, 6.4 × longer than wide, 0.4 × as long as hind tibia and 1.0 × as long as hind metatarsus, moderately bent upwards apically.
Color. Body mainly reddish-yellow. Flagellum brownish, basal flagellomere ochreous. Mesosoma reddishyellow; side of pronotum ventrally yellow. Tergites yellowish; ovipositor sheath pale brown. Fore and mid coxae and all trochanters cream-yellow, legs otherwise yellow; hind tibia not distinctly infuscate apically; hind tarsus pale brownish. Pterostigma ochreous-hyaline.
♁ unknown.
Taxonomical remark. The species belongs to the subgenus Stictopisthus and is characterized by its yellow body color, wide face, slightly depressed mesosoma, smooth scuto-scutellar groove and small ocelli.
description: Published as part of Riedel, Matthias, 2023, Contribution to the taxonomy of the Southeast Asian Mesochorinae (Hymenoptera, Ichneumonidae), pp. 1-72 in Zootaxa 5245 (1) on pages 12-13, DOI: 10.11646/zootaxa.5245.1.1, http://zenodo.org/record/7673309