Gnathochorisis leleji Humala, 2021

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

Gnathochorisis leleji Humala sp. nov.

Figures 1-5 , 6-8

Material examined.

Holotype: Malaysia • ♀; N. Borneo, Sabah, Sipitang, Mendolong ; [4.93°N, 115.76°E, exact locality uncertain]; T4/R; 14 Mar. 1989; S. Adebratt leg.; MZLU . Paratypes: Malaysia; same data as for holotype, but T3/W5; • 2 ♀♀; 2 Mar. 1989; MZLU and ZISP • 1 ♂; 8 Mar. 1989; ZISP • 1 ♂; 31 Mar. 1989; MZLU .

Diagnosis.

Gnathochorisis leleji sp. nov. can be distinguished from the majority of species of the genus by the lack of closed areolet. From the other two similar known species without areolet ( G. flavipes and G. fuscipes Humala & Lee, 2016), the new species differs in the strongly transverse head, and stronger apophyses on propodeum. From the East Palaearctic G. fuscipes , the new species differs in having a narrow face with width 0.45 times head width at the level of antennal sockets (0.51-0.53 times in G. fuscipes ), slenderer flagellum with first flagellomere about 4.7 times as long as wide (3.9 times in G. fuscipes ), predominantly yellow hind legs (hind coxa dark brown in G. fuscipes ), and a shorter ovipositor - 0.8 times as long as first tergite (as long as first tergite in G. fuscipes ). From the Palaearctic G. flavipes it differs in lack of yellowish posterior band on T2 (present in G. flavipes ) and inclivous nervellus (almost vertical in G. flavipes ). The new species is also characterized by the unique semicircular formation with reticulate microsculpture of T4 of male metasoma, not known in other congeners.

Description.

Female (Figs 1-5 ). Body length 4.0-4.1 mm; fore wing length 3.3-3.4 mm.

Head. Head width 1.25 times its height; face width at level of antennal sockets 1.7 times its height, 0.45 times head width, subpolished and closely punctate with long sparse setae; frons, vertex and occiput matt; occipital carina present; eyes large, convex, without setae, inner orbits slightly divergent ventrally (Fig. 2 ); clypeus width 1.6 times its height, weakly separated from face, with posterior margin truncate; anterior tentorial pits distinct; malar space 1.8 times as long as basal width of mandible; subocular sulcus nearly straight; mandibles bidentate, tapered, lower tooth shorter than upper tooth (Fig. 2 ). Antenna long, with 21 flagellomeres, scape long, subcylindrical, about 2.3 times as long as wide; first flagellomere 4.4-4.7 times as long as wide apically, second flagellomere 3.5-3.6 times as long as wide apically. Head strongly transverse, temple very short; ocelli of moderate size, ocular-ocellar line 1.1 times as long as maximum diameter of lateral ocellus; postocellar line 1.3 times as long as maximum diameter of lateral ocellus (Fig. 3 ).

Mesosoma. Mesosoma 1.4 times as long as maximum height; epomia well developed; mesoscutum nearly polished, notauli deep, extending to centre of mesoscutum, forming rugulose area there (Fig. 3 ); epicnemial carina complete, ending close to upper anterior corner of mesopleuron; sternaulus short but distinct; scutellum high; propodeum polished, with complete carination, area superomedia clearly transverse, 0.7 times as long as wide (Fig. 4 ), apophyses well developed with rounded apices (Fig. 5 ). Mesopleuron and metapleuron polished. Fore wing without areolet; vein 2m-cu with two bullae; hind wing with nervellus (cu-a + CU) inclivous, intercepted in lower 0.3. Hind leg with coxa punctate; femur somewhat inflated, 3.0 times as long as maximum width; basitarsus 0.4 times as long as hind tibia, tibial spurs slender, and claws strongly curved.

Metasoma. First metasomal segment 1.6 times as long as its maximum posterior width, postpetiole with dorsal carinae and irregular longitudinal striae; dorso-lateral carina distinct, extending above spiracle; glymma absent, spiracle situated at 0.5 length of first tergite, apex of first sternite at 0.4 of segment; T2 0.8 times as long as its maximum posterior width, with small indistinct first thyridium and more conspicuous second thyridium behind the middle, longitudinally striate in anterior 3/4, subpolished in posterior 1/4 (Fig. 5 ). Remaining tergites subpolished; sternites membranous with sclerotized patches on S2 to S7. Ovipositor upcurved with dorsal subapical notch, ovipositor sheath 0.8 times as long as first tergite and 0.75 times as long as hind tibia.

Colour. Dark brown. Clypeus, mandibles, excluding brown teeth, palpi, mouthparts, scape and pedicel ventrally, dorso-lateral corner of pronotum, tegula, fore and mid coxae and trochanters yellowish white. Face, flagellum, lower malar space, propleuron, mesepisternum, tergites 2-7 and sclerotized patches of sternites brown. Fore and mid femur, tibia and tarsus and hind leg yellowish, excluding dark brown hind femur posteriorly, anterior narrow band and posterior third of hind tibia. Wings hyaline, veins and pterostigma brown.

Male (Figs 6-8 ). Body length 4.1 mm; fore wing length 2.9 mm.

Similar to female, but slenderer. Antenna with 20-21 flagellomeres, first flagellomere 4.5 times as long as wide; T4 anteriorly with weakly sclerotized triangular area surrounding a medio-anterior semicircular formation with reticulate microsculpture (Fig. 8 ).

Face, clypeus, mandibles, lower frontal orbits, malar space, gena, palpi, mouth parts, scape, pedicel, upper posterior corner of pronotum, tegula, bases of wings, fore and mid coxae and trochanters yellowish white. Subtegular ridge, rest of fore and mid legs, and hind legs yellowish, excluding brown hind femur posteriorly, anterior narrow band and posterior third of hind tibia. Flagellum brownish; T1 dark brown, rest of metasoma brown, excluding yellowish anterior part of T4 and bases of T5 to T7.

Etymology.

The new species is named in honour of Prof. Arkady S. Lelej - a well-known Russian entomologist, in recognition of his significant contribution to the study of Hymenoptera , and also in celebration of his 75th birthday.

Distribution.

Malaysia (Sabah).

Figures

Figures 1 - 5. Gnathochorisis leleji sp. nov., holotype female 1 habitus, lateral view 2 head, anterior view 3 head and mesoscutum, dorsal view 4 propodeum, dorsal view 5 metasoma, tergites 1 - 2, dorsal view. Scale bar: 1.0 mm (1).

Figures 6 - 8. Gnathochorisis leleji sp. nov., paratype male 6 habitus, lateral view 7 head, anterior view 8 metasoma, tergites 3 - 5, dorsal view. Scale bar: 1.0 mm (6).