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

description: Mesochorus (Mesochorus) sapaensis nov. sp.
(Figs 5F, 12A, 19C, 23L)
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 is derived from the town Sa Pa which is close to the collection site.
Description. ♀: Body length 4.0 mm. Length of fore wing 3.7 mm.
Head. Flagellum with 33 flagellomeres; 1 st flagellomere 6.2 × longer than wide, 0.6 × as long as eye and 1.6 × longer than 2 nd flagellomere; 2 nd flagellomere 4.3 × longer than wide; preapical flagellomere 2.5 × longer than wide. Temple moderately and roundly narrowed behind eye, dorsally 0.6 × as long as eye. OED 1.5 × and OOD 0.8 × ocellar diameter. Frons smooth medially, with sparse punctures and fine aciculation laterally. Face (Fig. 12A) densely punctate, with central longitudinal ridge in dorsal half, width 1.0 × combined length of face and clypeus and 0.8 × eye length; inner eye margins parallel. Subantennal transverse carina dipped medially. Malar space and ventral 0.2 of facial orbit striate. Malar space 0.5 × 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 densely punctate on lateral lobe, rugose-punctate apicomedially. Scuto-scutellar groove smooth. Scutellum moderately convex, with fine sparse punctures, without lateral carina and apical tubercle. Mesopleuron with rather dense punctures fronto-dorsally and with fine sparse punctures ventrally. Dorsal end of epicnemial carina separated from frontal margin of mesopleuron. Metapleuron with fine sparse punctures. Submetapleural carina low. Propodeum (Fig. 19C) completely carinate. Area basalis triangular, 1.5 × longer than wide, with short apical stalk. Area superomedia 2.0 × longer than wide and 1.3 × longer than area petiolaris; anterior transverse carina (costula) reaching 4/10 of its length. Area petiolaris as long as wide. Hind femur 4.9 × longer than wide; hind metatarsus 0.5 × as long as hind tibia and 2.6 × longer than 2 nd hind tarsomere; hind claw with c 4 long teeth. Areolet pointed frontally; vein 2m-cu in its middle. Vein 1cu-a interstitial. Postnervulus intercepted basad its middle. Hind wing with 5 distal hamuli. Nervellus of hind wing vertical.
Metasoma. 1 st tergite 2.6 × longer than wide. Postpetiolus distinctly striate. 2 nd tergite 1.1 × longer than wide. Thyridium roundish. Ovipositor sheath (Fig. 23L) densely pilose, slightly saber-shaped, 6.4 × longer than wide, 0.5 × as long as hind tibia and 0.9 × as long as hind metatarsus, moderately narrowed in apical 0.4.
Color. Flagellum brown; scape, pedicel and three basal flagellomeres ochreous. Head reddish-yellow. Palps, mandible except teeth and malar space cream-yellow. Facial orbit and ventral half of frontal orbit yellowish. Frons medially, stemmaticum and occiput dorsally blackish. Hind edge of pronotum and tegula cream-yellow. Mesoscutum black, with H-shaped reddish ventral spot. Scutellum red, brownish basally. Pronotum red, yellowish ventrally, propleuron yellow. Mesopleuron black, with some reddish suffusion. Metapleuron and propodeum black, propodeum reddish in apical third. 1 st tergite black, red basally. 2 nd tergite black, with triangular reddish spot in apical 2/3 and yellow apical band. 3 rd yellow, with brown lateral stripes. Following tergites yellowish. Ovipositor sheath ochreous. Fore and mid coxae and all trochanters cream-yellow; fore and mid legs otherwise yellow. Hind coxa yellow; hind femur reddish-yellow; hind tibia yellow, narrowly at base and in apical 0.2 blackish, with weak subbasal brown spot; hind tarsus pale brown. Pterostigma brown, proximally and distally paler.
♁. Male unknown.
Taxonomical remark. With the black basal and pale apical tergites, this new species belongs to the declinans group sensu Schwenke (1999). It is characterized by its narrow face, mainly blackish mesopleuron, striate postpetiolus, strongly pectinate hind claw, and short and saber-shaped ovipositor sheath.
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 page 31, DOI: 10.11646/zootaxa.5245.1.1, http://zenodo.org/record/7673309