Syzeuctus laoticus Riedel, 2022

Watanabe, Kyohei & Riedel, Matthias, 2024, Revision of the genus Syzeuctus Förster, 1869 (Hymenoptera, Ichneumonidae, Banchinae) from Japan, Zootaxa 5496 (1), pp. 35-71 : 52-54

Syzeuctus laoticus Riedel, 2022

( Figs 1 F , 2 H , 12 A–F )

Syzeuctus laoticus Riedel, 2022: 267 .

Materials examined. JAPAN: [Honshu], 1 F, Saitama Pref., Chichibu City, Otaki, Irikawa forest road, 20–21. VII. 2013, N. Kikuchi leg. ( KPMNH) . LAOS: 1 F (holotype), Prov. Hua Phan Prov., Phon-Pan , Umg. Ort Ban Saleui, 20. VI. 2013, KJa, leg. C. Holzschuh & natives (Linz) .

Description based on Japanese specimen. Female (n = 1). Body polished and covered with punctures and silvery setae; length 8.7 mm. Setae on head and mesosoma not exceptionally long and erect.

Head 0.57 × as long as wide. Combined length of clypeus and face 1.0 × facial width. Clypeus smooth except for dorsal margin sparsely punctate, slightly convex in lateral view, without central transverse ridge. Face densely punctate, slightly convex medially in lateral view, without a pair of convexities just above of each anterior tentorial pit. Frons almost flat, without horns or convexities. Malar space 0.7 × as long as basal mandibular width. Genal carina low ventrally, reaching mandibular base. POL 1.75 × as long as OD. OOL 1.0 × as long as OD. Temple weakly roundly narrowed behind eye in dorsal view ( Fig. 12 D ). Antenna with 42 flagellomeres. FL I 3.75 × as long as maximum depth in lateral view and 1.5 × as long as FL II. Preapical flagellomere 1.2 × as long as maximum width.

Mesosoma coarsely and densely punctate, 1.4 × as long as maximum height. Pronotum with small smooth area just behind of epomia. Epomia present, its dorsal end not reaching dorsal margin. Mesopleuron punctate; speculum with a large smooth area ( Fig. 12 E ). Epicnemial carina present latero-ventrally and ventrally, its dorsal end close to anterior margin of mesopleuron, with weak angulation ( Fig. 1 F ). Dorsal surface of propodeum with weak transverse rugae posteriorly. Posterior transverse carina of propodeum absent laterally, shortly and obsoletely present medially. Fore wing length 6.6 mm. Areolet receiving vein 2m-cu slightly basal to the outer angle, petiolated anteriorly; petiole as long as areolet ( Fig. 12 F ). Fore wing vein 1cu-a subvertical, slightly postfurcal to vein M&RS. Nervellus reclivous, intercepted posterior to the middle. Hind femur 5.75 × as long as maximum depth in lateral view. Ratio of length of first to fifth hind tarsomeres 3.9: 2.0: 1.4: 0.7: 0.8. Hind tarsal claws simple except for minute subbasal teeth, moderately bent apically (less than 90°) ( Fig. 2 H ).

Metasoma. T I 2.0 × as long as maximum width, finely punctate except for smooth areas on median longitudinal area, area along posterior margin and lateral sides. T II 1.2–1.4 × as long as maximum width, finely and densely punctate. T III to T V coriaceous with fine punctures. Ovipositor sheath 3.35 × as long as hind tibia, ca. 1.2 × as long as fore wing, and shorter than body length.

Colouration ( Figs 12 A–F ). Body (excluding wings and legs) black. Clypeus, face except for a dorso-median longitudinal black stripe, malar space, inner and outer orbits, ventral surfaces of scape and pedicel, and palpi yellow. Flagellum largely reddish-brown to brown. Pronotum except for antero-median part and area along posterior margin, posterior part of propleuron, a pair of antero-lateral triangular markings and a median marking of mesoscutum, scutellum except for an antero-median black spot, postscutellum, subtegular ridge, large C-shaped marking of mesopleuron, upper division of metapleuron, posterior part of metapleuron, a pair of antero-lateral spots of propodeum, and a posterior triangle marking of propodeum yellow. Base of T I with a pair of yellow markings. Posterior margins of T I to T IV each with yellow to ivory band. Posterior margins of T V to T VII largely tinged with red to reddish-brown. Metasomal tergites more or less tinged with red to reddish-brown on T III to T VII. Membranous parts of metasomal sternites and subgenital plate except for an apical blackish spot yellow. Ovipositor reddish-brown. Wings hyaline, apical part with slightly darkened clouded area. Veins and pterostigma blackish-brown except for yellowish-brown wing base. Fore and mid legs yellow. Hind coxa black laterally, yellow dorsally and ventrally. Hind trochanter black with yellow apical margin. Hind trochantellus yellow. Hind femur dark brown except for yellowish-brown apically. Hind tibia yellowish-brown, its apical part darkened. Hind tibial spurs pale yellowish-brown. Hind tarsus brown except for blackish-brown fifth tarsomere; bases of first to third tarsomeres, apex of third tarsomere, and fourth tarsomere paler than other parts.

Male. Unknown.

Distribution. Japan (Honshu) and Laos. New to Japan.

Bionomics. Unknown.

Remarks. The Japanese specimen differs from holotype by the smaller body, the T I 2.0 × as long as maximum width (2.6 × in holotype), and ovipositor sheath slightly shorter than holotype, But we conclude that these differences are intraspecific variation.

Figures

FIGURE 1. Epicnemial carina of Japanese species of Syzeuctus spp., females—A: S. apicifer (Walker, 1874); B: S. brevicaudus sp. nov. (holotype); C: S. coreanus Uchida, 1928; D: S. flavitarsis sp. nov. (paratype); E: S. flavofacialis Kang & Lee, 2020; F: S. laoticus Riedel, 2022; G: S. maculatus Sheng, 2009; H: S. nigrus sp. nov. (holotype); I: S. rufiapicalis sp. nov. (holotype); J: S. sambonis Uchida, 1928; K: S. takaozanus Uchida, 1928; L: S. yamatonis sp. nov. (holotype).

FIGURE 2. Hind tarsal claws and metasomal tergites of Japanese species of Syzeuctus spp., females (A-N) and males (O–S)— A: S. apicifer (Walker, 1874); B: S. brevicaudus sp. nov. (holotype); C: S. coreanus Uchida, 1928; D, O: S. flavitarsis sp. nov. (holotype); E–G: S. flavofacialis Kang & Lee, 2020; H: S. laoticus Riedel, 2022; I: S. maculatus Sheng, 2009; J: S. nigrus sp. nov. (holotype); K, P, Q: S. rufiapicalis sp. nov. (K: holotype; P, Q: paratype); L: S. sambonis Uchida, 1928; M: S. takaozanus Uchida, 1928; N, R, S: S. yamatonis sp. nov. (N: holotype; R, S: paratype)—A–E, G–N: outer claw; F: inner claw; O, P, R: T I and T II, lateral view; Q, S: T I and T II, dorsal view.

FIGURE 12. Syzeuctus laoticus Riedel, 2022, female from Japan—A: lateral habitus; B: head, mesosoma, and metasoma, dorsal view; C: head, frontal view; D: head, dorsal view; E: pronotum and mesopleuron, lateral view; F: fore wing.