Gnathochorisis Foerster , 1869

Humala, Andrei E., 2021, First records of the genus Gnathochorisis Foerster (Hymenoptera, Ichneumonidae, Orthocentrinae) in the Oriental region, Journal of Hymenoptera Research 84, pp. 103-113 : 103

Genus Gnathochorisis Foerster, 1869

Gnathochorisis Forster, 1869: 152. Type species: Gnathochorisis flavipes Forster, 1871: 113.

Blapticus Forster, 1869: 171. Type species: Blapticus leucostomus Forster, 1871: 83.

Laepserus Forster, 1869: 205. Type species: Blapticus crassulus Thomson, 1888: 1289.

Acroblapticus Schmiedeknecht, 1911: 2173. Type species: Blapticus dentifer Thomson, 1888: 1288.

Description.

Fore wing 2.3-5.4 mm long. Body stout; head clearly transverse, clypeus small, weakly to strongly separated from face by a groove, flattened; occipital carina complete; face polished to slightly matt, sparsely to moderately punctate; eyes large, inner orbits subparallel to slightly divergent ventrally; mandible small, not or slightly twisted inwards, sometimes tapered and sinuous; lower tooth shorter than upper tooth; malar space with subocular sulcus; antenna moderately long; scape elongate, subcylindrical, hind margin of apical truncation not membranous; male flagellum lacking tyloids. Mesosoma finely or densely punctate on mesoscutum, polished on mesopleuron. Notauli short or reaching centre of mesoscutum, moderately deep; epomia usually weak and short. Epicnemial carina complete, dorsally distant from anterior margin of mesopleuron; propodeum polished or matt, usually with complete and distinct carinae, often with developed apophyses. Fore wing with areolet present or absent, sessile or short petiolate, rectangular when present. Hind wing with nervellus (cu-a + CU) intercepted below the middle, second abscissa of CU distinct. Hind legs stout, as a rule, hind femur strongly thickened, 2.85-4.9 times as long as broad, hind claws fairly large. First metasomal segment petiolate; sternite fused to tergite and reaching 0.5-0.6 of the segment, spiracles near middle of segment; glymma lacking. Second tergite matt or polished, often with longitudinal striae. Ovipositor upcurved, its sheath nearly as long as first tergite, with a dorsal subapical notch.

Diagnosis.

Gnathochorisis can be distinguished from other orthocentrine genera belonging to the tribe Helictini by the following combination of characters: body stout; scape subcylindrical, elongate, not inflated, and its hind margin of apical truncation not membranous; male flagellum lacking tyloids; female inner orbits subparallel or slightly divergent downwards; sternaulus short; propodeum usually with complete carinae; fore wing with sessile or shortly petiolate areolet, if areolet absent, then vein 2rs-m moderately long; hind femur stout; hind claws enlarged; first metasomal segment petiolate, its tergite and sternite fused and glymmae absent. Together with Symplecis , Catastenus Förster, 1869 and Eusterinx Förster, 1869, Gnathochorisis forms the so-called Eusterinx -group ( Wahl 1990; Wahl and Gauld 1998). This monophyletic group can be distinguished from other orthocentrines by the fused tergite and sternite of the first segment of metasoma, absence of glymmae, and mostly complete carination of the propodeum. Gnathochorisis differs from Catastenus and Symplecis in having ovipositor upcurved, with a dorsal subapical notch, 0.5-1.1 times as long as hind tibia, and female inner orbits subparallel or slightly divergent downwards. Gnathochorisis species can be distinguished from Eusterinx by stout body, transverse head and nervellus intercepted in lower half.