Mesochorus (Mesochorus) genator Riedel & Varga, 2022

Riedel, Matthias & Varga, Oleksandr, 2022, A checklist of the subfamily Mesochorinae (Hymenoptera, Ichneumonidae) from the Ukrainian Carpathians, Zootaxa 5100 (2), pp. 224-248 : 231-233

Mesochorus (Mesochorus) genator Riedel & Varga , sp. n. ( Fig. 11 )

urn:lsid:zoobank.org:act:4E0C4737-84CE-491E-A6AC-9BC0F43300EE

Holotype. UKRAINE: Transcarpathian Region : 1 ♀, 6.5 km N of Mala Ugolka, 48.259464 N, 23.619672 E, 750 m, beech forest, Malaise trap 6, 17.vii–16.viii.2013, leg. O. Varga ( ZSSM).

Description. Body length 4.2 mm.

Head ( Fig. 11B, C ). Flagellum slender, with>39 flagellomeres (tips broken off); 1 st flagellomere 7.5 × longer than wide and 0.8 × as long as eye, 2 nd flagellomere 4.2 × longer than wide. Temple strongly narrowed behind eye, dorsally 0.5 × as long as eye. Distance between lateral ocelli 0.5 × and distance of lateral ocellus to eye and 1.2 × ocellar diameter. Face width 1.0 × combined length of clypeus and face and 1.0 × eye length, with parallel sides, densely and coarsely rugose-punctate. Malar space and ventral half of facial orbit very widely striate. Malar space 0.9 × as long as width of mandibular base.

Mesosoma ( Fig. 11C, D ). Mesoscutum densely punctate. Mesopleuron with coarse dense and partly rugose punctures ventrally and finer dense punctures dorsally. Propodeum with area basalis triangular, about as long as wide; area superomedia almost rhombic, 1.4 × as long as wide, anterior transverse carina in the middle; area petiolaris about as long as wide. Legs slender, hind femur 4.7 × longer than wide. Hind claw covered with dirt, mid claw with one large basal tooth. Areolet sessile frontally, oblique; vein 2m-cu proximal to the middle. Vein 1cu-a postfurcal by 0.3 × its length. Pterostigma slender, 3.3 × longer than wide. Vein 2r+Rs reaching its distal 0.7.

Metasoma ( Fig. 11A, E ). 1 st tergite slender, 3.6 × longer than wide; postpetiolus smooth. 2 nd tergite 1.05 × longer than wide; thyridium transverse, comma-shaped. Ovipositor sheath very slender, stab-shaped, bare, c. 16 × longer than wide and 0.9 × as long as hind metatarsus.

Color. Head and flagellum yellow; gena and facial orbit pale yellowish; frons centrally and stemmaticum blackish; occiput diffusely brownish. Mesosoma yellowish; mesopleuron with blackish spot fronto-dorsally; mesoscutum with two sublateral black stripes and frontal-medial black mark; scuto-scutellar groove black; scutellum pale yellow. Propodeum black; areae basalis and superomedia entirely and area petiolaris laterally yellowish. Metasoma with 1 st tergite tricolored, 1 st sternite ivory basally, brown apically; petiolus reddish basally, black apically; postpetiolus black, with narrow reddish hind margin; 2 nd tergite black, with large yellow triangular spot in apical 0.6; 3 rd tergite yellow in basal 0.6, blackish laterally and apically; following tergites black medially, with ± yellowish sides. Legs yellow; hind coxa with black dorso-lateral spot, hind femur yellow, with diffusely reddish-brown pattern dorsally; hind tibia ivory, blackish in basal 0.2 and apical 0.3; hind tarsus except yellow base of metatarsus brownish. Pterostigma dark brown.

Male. Unknown.

Distribution. Only known from Western Ukraine. The specimen was collected in the primeval beech forest.

Taxonomical remark. This new species belongs to the dispar -group of Mesochorus and runs to M. faciator in the key of Schwenke (1999: 48-51). It is characterized by its wide malar space and widely striated facial orbits; narrow stemmaticum; in combination with characteristic coloration of propodeum, hind coxa, hind tibia and metasoma.

Figures

FIGURE 11. Mesochorus genator Riedel & Varga, sp. n., female, holotype. A—habitus, lateral view; B—face, frontal view; C—head and mesoscutum, dorsal view; D—propodeum, dorsal view; E—ovipositor, lateral view.