Syzeuctus rufiapicalis Watanabe & Riedel, 2024, sp. nov.
Creators: name: Watanabe, Kyohei
name: Riedel, Matthias
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Syzeuctus
Syzeuctus rufiapicalis

description: Syzeuctus rufiapicalis sp. nov.
(Figs 1 I, 2 K, P, Q, 17 A–H, 18 A–C)
Type series. Holotype: F, JAPAN, Honshu, Ishikawa Pref., Kaga City, Mt. Kariyasu-yama, 19–31. VII. 2022, K. Esaki leg., MsT (KPMNH). Paratypes: JAPAN: [Honshu] 1 F, Yamagata Pref., Mamurogawa Town, 18. VIII. 2012, Y. Matsubara & K. Fukuda leg., MsT (KPMNH); 1 F, Saitama Pref., Ogawa Town, Kinshouzan, 23. IX. 1995, M. Uchida leg. (KPMNH); 15 F, same data of holotype (10 F: KPMNH; 4 F: ZSM; 1 F, OMNH); 1 F & 1 M, ditto, 28. VI.–18. VII. 2002 (KPMNH); [Shikoku] 1 F, Ehime Pref., Kumakogen, Yurano, 31. VII. 2007, E. Yamamoto leg., MsT (EUM).
Description. Female (n = 20). Body polished and covered with punctures and silvery setae; length 9.25–12.2 (HT: 9.8) mm. Setae on head and mesosoma not exceptionally long and erect.
Head 0.55 × as long as wide. Combined length of clypeus and face 0.9–1.0 (HT: 0.9) × 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, with a pair of indistinct convexities just above of each anterior tentorial pit. Frons slightly concave, without horns or convexities. Malar space 0.75–0.8 (HT: 0.75) × as long as basal mandibular width. Genal carina low ventrally, reaching mandibular base. POL 1.5–1.9 (HT: 1.8) × as long as OD. OOL 1.25–1.7 (HT: 1.6) × as long as OD. Temple slightly roundly narrowed behind eye in dorsal view (Fig. 17 E). Antenna with 43–45 (HT: 45) flagellomeres. FL I 4.15–4.8 (HT: 4.3) × as long as maximum depth in lateral view and 1.6–1.8 (HT: 1.6) × as long as FL II. Preapical flagellomere 1.0 × as long as maximum width.
Mesosoma coarsely and densely punctate, 1.4–1.45 (HT: 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 densely punctate ventrally, sparsely punctate dorsally; speculum with a large smooth area, its ventral part with a rather deep concavity (Figs 17 F, G). Epicnemial carina present latero-ventrally and ventrally, its dorsal end remote from anterior margin of mesopleuron, without or with angulation (Fig. 1 I). Dorsal surface of propodeum without transverse rugae. Posterior transverse carina of propodeum largely absent medially, present laterally. Fore wing length 7.5–9.75 (HT: 7.6) mm. Areolet receiving vein 2m-cu slightly basal to the outer angle, petiolated anteriorly; petiole longer than areolet (Fig. 17 H). Fore wing vein 1cu-a slightly inclivous to subvertical, slightly postfurcal to vein M&RS. Nervellus reclivous, intercepted posterior to the middle. Hind femur 6.0–6.5 (HT: 6.5) × as long as maximum depth in lateral view. Ratio of length of first to fifth hind tarsomeres 4.0–4.1 (HT: 4.0): 2.0: 1.3–1.45 (HT: 1.4): 0.6–0.75 (HT: 0.7): 0.8–0.95 (HT: 0.9). Hind tarsal claws simple except for minute subbasal teeth, moderately bent apically (less than 90°) (Fig. 2 K).
Metasoma. T I 2.55–2.95 (HT: 2.85) × as long as maximum width, finely punctate except for smooth areas on median longitudinal area, area along posterior margin and lateral sides. T II 1.85–2.1 (HT: 1.85) × as long as maximum width, finely and densely punctate. T III to T V coriaceous with fine punctures. Ovipositor sheath 1.95–2.05 (HT: 1.95) × as long as hind tibia, ca. 0.7–0.8 (HT: 0.75) × as long as fore wing, and shorter than body length.
Colouration (Figs 17 A–H). Body (excluding wings and legs) black. Clypeus, mandible except for teeth, face except for three longitudinal stripes and area around anterior tentorial pits, malar space, inner orbit on frons and vertex, and outer orbit yellow. Antenna blackish-brown to brown. Pronotum with a pair of transverse yellow stripes. Mesoscutum with a pair of antero-lateral yellow markings and a median yellow marking (the latter sometimes divided into a pair of markings). Subtegular ridge, antero-dorsal spot of mesopleuron, tegula, scutellum except a median small black spot, postscutellum, a pair of antero-lateral spots of propodeum, and a posterior triangle marking of metapleuron and propodeum yellow. Mesopleuron sometimes (including holotype) with an antero-median yellow marking. Upper division of metapleuron sometimes (including holotype) yellow. Base and posterior margin of T I yellow. Posterior margins of T II and T III yellow. T IV to T VII largely reddish-yellow to red. Membranous parts of metasomal sternites largely yellow. Subgenital plate reddish-yellow. Ovipositor reddish-brown. Wings hyaline. Apical clouded area of fore wing slightly present. Veins and pterostigma blackish-brown except for yellowish-brown wing base. Fore and mid legs yellow except for black area of mid coxa and black mid fifth tarsomere. Hind leg blackish-brown to black except for a dorsal small yellow spot of coxa, trochantellus, apex of femur, bases of tibia and first tarsomere.
Male (n = 1). Similar to female (Figs 18 A–C). Malar space 0.9 × as long as basal mandibular width. Antenna with 46 flagellomeres. Tergal spiracles enlarged and with circular felt-like area, its length more than 0.2 × as long as T I (Figs 2 P, Q, 18 A, C). Basal part of T I almost smooth (Fig. 2 Q). Yellow area of body larger than female. Mesosternum with a large yellow area.
Distribution. Japan (Honshu and Shikoku).
Etymology. The specific name is from red apical part of metasomal tergites.
Bionomics. Unknown.
Remarks. In the key provided by Riedel (2021), the female runs to couplet 44 (S. maroccanus Riedel, 2021), but differs by the T I and (at least) basal part of T II black (red in S. maroccanus), the fore wing without a strong apical clouded area (with a strong brown apical spot in S. maroccanus), and the malar space 0.75–0.8 × as long as basal mandibular width (0.5 × in S. maroccanus). The male runs to couplet 7 (S. dusmeti Seyrig, 1928) of the key, but differs by the posterior transversal carina of propodeum more or less complete (absent medially in S. dusmeti) and T II and T III without a conspicuous yellow posterior band (with yellow bands in S. dusmeti). The female of this species also resembles S. sparsus Sheng, 2009 but can be distinguished by the antenna with 43–45 flagellomeres (51–52 flagellomeres in S. sparsus) and a longer malar space (0.75–0.8 × versus 0.5 × in S. sparsus).
description: Published as part of Watanabe, Kyohei & Riedel, Matthias, 2024, Revision of the genus Syzeuctus Förster, 1869 (Hymenoptera, Ichneumonidae, Banchinae) from Japan, pp. 35-71 in Zootaxa 5496 (1) on pages 60-62, DOI: 10.11646/zootaxa.5496.1.2, http://zenodo.org/record/13331013