Xynobius setosiscutum van Achterberg, 2023

Han, Yunjong, van Achterberg, Cornelis, Lee, Heung-Sik & Kim, Hyojoong, 2023, Two new Palaearctic species of Xynobius Foerster (Hymenoptera, Braconidae, Opiinae), ZooKeys 1160, pp. 61-74 : 61

Xynobius setosiscutum van Achterberg sp. nov.

Figs 12 , 13-23

Type material.

Holotype, ♀ (RMNH), "Norway: RY, Sokndal, Skittmyr, 58.3509°N, 6.3054°E, 20.vii.-8.viii.2020, MT [= Malaise trap], J. Birkeland, RMNH’21”. Paratypes (5): 1 ♂ (RMNH), topotypic, but 10-20.vii.2020; 1 ♀ (MSC), "Norway: RY, Ra, Hølland, 58.5245°N, 5.8352°E, 29.vi. -16.vii.2020, MT, A.T. Mjøs, RMNH’21”; 1 ♀ (RMNH), "Norway: RY, Time, Mossige, 58.6900N 5.7239E, 17.ix.-11.x.2020, MT, A.T. Mjøs, RMNH’21”; 1 ♀ (RMNH), "Norway: RI, Hjelmeland, 59.2312°N, 6.1653°E, 16.ix.-31.x.2020, MT, A.T. Mjøs, RMNH’21”; 1 ♀ (RMNH), "Norway: ROY, Sokndal, Rekvei, Long. lat. 58.2035°N, 6.1559°E, Malaise trap, 7.ix.2019, J. Birkeland".

Diagnosis.

Antenna with 32-34 segments, flagellum dark brown but apical segments more or less brown; temple medium-sized (Fig. 19 ; roundly narrowed and eye in dorsal view 2.6 × longer than temple); mesoscutum and scutellum evenly and conspicuously setose (Fig. 15 ); notauli largely absent on mesoscutal disc (a derived character state in common with X. subparallelus sp. nov. from Japan); hind femur comparatively robust (Figs 12 , 17 ; about 4 × longer than wide); pterostigma narrow elliptical and gradually narrowed apically (Fig. 13 ); vein m-cu of fore wing distinctly antefurcal and posteriorly angulate with vein 2-CU1 (Fig. 13 ); first tergite distinctly widened posteriorly (Fig. 16 ; 1 .2-1.4 × longer than its apical width in ♀, about 1.6 × longer in ♂); second tergite regularly and costate-like striate (Fig. 16 ) and third tergite smooth; setose part of ovipositor sheath shorter than first metasomal tergite (Fig. 17 ) and at most slightly protruding beyond apex of metasoma. The new species is very similar to X. subparallelus sp. nov. from Japan because of the reduction of the notauli and the conspicuous setosity of the mesoscutum and scutellum. However, it differs by having the first tergite distinctly widened posteriorly (subparallel-sided in X. subparallelus ), distinctly wider temple (comparatively narrow), apex of third and fourth metasomal tergites yellow (blackish or dark brown), second tergite regularly and coarsely striate (finely and irregularly striate) and hind femur less slender, about 4 × longer than wide (more robust, about 5 × longer than wide).

Description.

Holotype, ♀, length of body 3.0 mm, of fore wing 3.3 mm.

Head. Antenna with 34 segments and 1.2 × as long as fore wing; third segment 1.4 × longer than fourth segment, length of third, fourth and penultimate segments 4.7 ×, 3.3 ×, and 2.5 × their width, respectively (Figs 21 , 22 ); width of head 1.8 × its median length in dorsal view; no depression behind stemmaticum; vertex flattened and punctulate; OOL: diameter of ocellus: POL= 37:15:22 (Fig. 19 ); frons largely flattened and setose (Fig. 18 ); face finely punctate, shiny and with conspicuously long setae (Fig. 18 ); clypeus convex dorsally, semi-circular, largely smooth (except punctulation because of very long setae) and its ventral margin thick and concave, width of clypeus 2.1 × its maximum height and 0.5 × minimum width of face; hypoclypeal depression large and deep (Fig. 18 ); eye in dorsal view 2.6 × longer than temple and temple behind eye roundly narrowed (Fig. 19 ); occipital carina distinct but dorsally finer and medio-dorsally absent (Fig. 19 ); temple and malar space smooth; length of malar space 0.8 × basal width of mandible and 0.2 × height of eye; malar suture nearly complete, shallow; mandible slightly twisted apically, both teeth robust, basally symmetric or nearly so, basal half with lamelliform ventral carina (Figs 18 , 20 ); length of maxillary palp 1.3 × height of head; labial palp segments elongate.

Mesosoma. Length of mesosoma 1.5 × its height (Fig. 14 ); laterally pronotum smooth only anteriorly, medially and posteriorly with few crenulae; dorsal pronope absent, medial area rather short, laterally with narrow groove; propleuron weakly evenly convex, with long setae, shiny and smooth (Fig. 14 ); mesopleuron smooth except for coarsely crenulate precoxal sulcus medially (Fig. 14 ); mesosternum densely setose; postpectal carina absent; pleural sulcus smooth or nearly so; mesosternal sulcus narrow and finely crenulate; metapleuron largely smooth dorsally and ventrally rugulose, long setose (Fig. 14 ); mesoscutum steeply raised above pronotum, densely setose, rather shiny and punctulate; notauli short, only impressed anteriorly and absent on most of mesoscutum, rather deep and largely smooth (Fig. 15 ); medio-posterior depression of mesoscutum rather deep medially, linear and medium-sized; transverse suture of mesoscutum present; scutellar sulcus deep and broad medially, with four carinae and medially 0.2 × as long as scutellum; scutellum largely smooth and setose, punctulate, weakly convex, with narrow subposterior depression (Fig. 15 ); side of scutellum partly punctate (Fig. 15 ); propodeum largely vermiculate-rugose but posteriorly largely smooth between carinae, anteriorly with short medio-longitudinal carina (Figs 15 , 16 ).

Wings. Fore wing (Fig. 13 ): pterostigma elongate-elliptical, 5 × as long as its maximum width and gradually merging into vein 1-R1; vein M+CU1 weakly curved and only distal quarter sclerotized; 1-R1 reaching wing apex; r:3-SR:SR1 = 4:45:72; 2-SR:3-SR:r-m = 20:45:16; vein r slightly widened, its length 0.3 × width of pterostigma, arising far before middle of pterostigma; 2-SR straight; m-cu distinctly antefurcal, largely unpigmented and slightly curved, angled with 2-CU1; cu-a slightly postfurcal and vertical; 1-CU1 widened; vein 3-CU1 distinctly longer than vein CU1b (Fig. 13 ). Hind wing: M+CU:1-M:1r-m = 20:21:12; cu-a straight; m-cu present.

Legs. Second to fourth fore tarsal segments hardly longer than wide; hind femur, tibia and basitarsus 4.0 ×, 9.6 ×, and 5.3 × as long as wide, respectively (Fig. 17 ); hind femur densely and long setose.

Metasoma. First tergite 1.2 × as long as wide apically and slightly widened apically, dorsope rather small, its surface convex medially and largely coarsely striate, dorsal carinae distinct in basal third of tergite (Fig. 16 ); second tergite regularly costate-like striate and following tergites smooth; second suture absent dorsally, except laterally; setose part of ovipositor sheath 0.04 × as long as fore wing (entire sheath 0.06 ×), 0.3 × first tergite, and 0.1 × as long as hind tibia; sheath slightly protruding beyond apex of metasoma; hypopygium truncate ventro-apically, membranous medially and about 0.6 × as long as first tergite (Fig. 17 ).

Colour. Black or blackish brown; scape and pedicel largely (but dorsally partly dark brown), mandible, palpi, coxae, trochanters and trochantelli and femora basally ivory or whitish; hind tarsus infuscate; remainder of legs, head except occiput, vertex and frons medially, mesoscutum antero-laterally, scutellum laterally, pronotum partly, mesopleuron antero-dorsally and ventrally, third to fifth tergites apically, sixth and seventh tergites, and metasoma ventrally yellow; scutellum mainly dark reddish brown; pronotum medially and propleuron, pterostigma, and most veins brown; antenna dark brown, ventrobasally yellowish, apically nearly brown; ovipositor sheath dark brown; wing membrane subhyaline (Fig. 13 ).

Variation. Length of body 2.9-3.1 mm, of fore wing 3.2-3.5 mm (of ♂ 2.9 mm); antennal segments in ♀ 32 (2) and 34 (2) and in ♂ 33 (1); flagellum dark brown or brown; mesoscutum posteriorly entirely black or partly brown and medio-posterior depression droplet-shaped or linear; vein m-cu of fore wing angled with vein 2-CU1 or gradually merging into vein 2-CU1; hind femur 4.0-4.2 × longer than wide; first tergite 1.2-1.4 × longer than wide apically in ♀ (about 1.6 × longer in ♂); length of setose part of ovipositor sheath 0.03-0.04 × fore wing (exposed sheath 0.06-0.08 ×).

Distribution.

Southwestern Norway.

Biology.

Unknown.

Etymology.

Named after the entirely and conspicuously setose mesoscutum; " setosus " is Latin for “bristly”, and " scutum " is Latin for “shield”.

Remarks.

This species runs to the subgenus Opius Allotypus Foerster sensu Fischer, and with difficulty to Opius saevulus Fischer, 1958 (mesosoma less than 1.5 × longer than high in lateral view) or O. irregularis Wesmael, 1835 (mesosoma 1.5 × longer than high in lateral view), in the keys by Fischer (1972). Both of these species have nothing in common with the new species and both belong to the genus Apodesmia Foerster, 1863 because the occipital carina is curved and connected to hypostomal carina. Actually, the new species is more related to X. aciculatus (Thomson, 1895) because they share the setose middle lobe of the mesoscutum, the striate second tergite, the (at least partly) yellow face and clypeus, and the comparatively robust first tergite in females. The new species has the lateral mesoscutal lobes largely setose medially (glabrous in X. aciculatus ); vein 3-CU1 of fore wing distinctly longer than vein CU1b (about of equal length); vein r of fore wing widened and shorter (narrow and longer); antenna of ♀ with 32-34 segments (with 28-31 segments); sixth metasomal tergite yellow largely dark brown); second tergite coarsely striate (finely striate); notauli largely absent on mesoscutal disc (notauli complete on disc); and vein m-cu of fore wing antefurcal (postfurcal).

Figures

Figure 1. Xynobius subparallelus Han & van Achterberg, sp. nov., holotype, ♀, Japan, habitus, lateral.

Figure 12. Xynobius setosiscutum van Achterberg, sp. nov., holotype, ♀, Norway, habitus, lateral.

Figures 13 - 23. Xynobius setosiscutum van Achterberg, sp. nov., holotype, ♀, Norway 13 wings 14 head and mesosoma lateral 15 mesosoma dorsal 16 propodeum and 1 st to 4 th metasomal segments dorsal 17 hind leg and metasoma lateral 18 head anterior 19 head dorsal 20 mandible latero-ventral 21 antenna 22 base of antenna 23 apex of antenna.