Syzeuctus yamatonis 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 yamatonis

description: Syzeuctus yamatonis sp. nov.
(Figs 1 L, 2 N, R, S, 22 A–F, 23 A–D)
Type series. Holotype: F, JAPAN, Honshu, Kanagawa Pref., Yokohama City, Enkaizan, 27. V. 2009, K. Kubo leg. (KPMNH). Paratypes: JAPAN: [Hokkaido] 1 F, Sapporo City, Hitsujigaoka, 18–25. VIII. 2008, K. Konishi leg., MsT (KPMNH); 1 F, ditto, 23–25. VII. 2010, K. Takashino leg., MsT (EUM); [Honshu] 1 F, Yamagata Pref., Mamurogawa Town, 21. VIII. 2012, Y. Matsubara & K. Fukuda leg., MsT (KPMNH); 1 M, same locality of holotype, 19. VI. 2009, K. Kubo leg. (KPMNH); 1 F, Niigata Pref., Myokou, City, Suginosawa, Mt. Sasagamine, 16. VII. 2013, S. Shimizu leg. (KPMNH); 1 F, ditto, 7. VIII. 2013 (ZSM); 1 M, Yamanashi Pref., Narusawa Vil., Kouyoudai, 31. V. 2017, K. Watanabe leg. (KPMNH); 1 F, Fukui Pref., Oono City, Koike, Ropponnoki, 29. VII. 1982, T. Murota leg. (KPMNH); 1 F, Tottori Pref., Wakasa Town, Mt. Hyonosen, 6. VIII. 2011, K. Watanabe leg., Light trap (KPMNH); [Shikoku] 1 F, Ehime Pref., Mt. Ishizuchi, Jyojyusha, 29. VII. 1955, S. Ueda leg. (EUM); [Kyushu] 1 M, Kagoshima Pref., Cape Sata, 11. VII. 1961, A. Nakanishi leg. (MNHAH).
Description. Female (n = 8). Body polished and covered with punctures and silvery setae; length 9.0–10.8 (HT: 10.8) mm. Setae on head and mesosoma not exceptionally long and erect
Head 0.6 × as long as wide. Combined length of clypeus and face 0.95–1.1 (HT: 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 slightly concave, without horns or convexities. Malar space 0.5–0.6 (HT: 0.5) × as long as basal mandibular width. Genal carina lamella-like ventrally, reaching mandibular base. POL 1.6–1.8 (HT: 1.7) × as long as OD. OOL 1.2–1.4 (HT: 1.2) × as long as OD. Temple weakly roundly narrowed behind eye in dorsal view (Fig. 22 D). Antenna with 42–44 (HT: 44) flagellomeres. FL I 4.1–4.7 (HT: 4.7) × as long as maximum depth in lateral view and 1.5–1.85 (HT: 1.75) × 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 (Fig. 22 E). Epicnemial carina present latero-ventrally and ventrally (Fig. 1 L). Dorsal surface of propodeum without transverse rugae. Posterior transverse carina of propodeum largely absent medially, obsolete laterally. Fore wing length 7.6–8.2 (HT: 8.2) mm. Areolet receiving vein 2m-cu slightly basal to the outer angle, petiolated anteriorly; petiole as long as areolet (Fig. 22 B). Fore wing vein 1cu-a subvertical, slightly postfurcal to vein M&RS. Nervellus reclivous, intercepted posterior to the middle. Hind femur 5.2–5.7 (HT: 5.25) × as long as maximum depth in lateral view. Ratio of length of first to fifth hind tarsomeres 4.0–4.1 (HT: 4.1): 2.0: 1.3: 0.6–0.7 (HT: 0.7): 0.7–0.8 (HT: 0.8). Hind tarsal claws simple except for minute subbasal teeth, moderately bent apically (less than 90°) (Fig. 2 N).
Metasoma. T I 1.9–2.4 (HT: 2.2) × as long as maximum width, finely punctate laterally, smooth medially. T II 1.35–1.5 (HT: 1.5) × as long as maximum width, finely and densely punctate. T III to T V coriaceous with fine and dense punctures. Ovipositor sheath 2.1–2.5 (HT: 2.3) × as long as hind tibia, ca. 0.8–0.85 (HT: 0.8) × as long as fore wing, and shorter than body length.
Colouration (Figs 22 A–F). Body (excluding wings and legs) black. Clypeus, mandible except for teeth, malar space, a pair of small yellow spots below antennal sockets, orbits on face, frons, vertex and gena, and palpi yellow. Antenna blackish-brown to reddish-brown. Scape and pedicel usually partly tinged with yellow ventrally. Two spots of collar, a L-shape marking of dorsal margin of pronotum, a pair of antero-lateral markings and a median marking of mesoscutum, subtegular ridge, antero-dorsal and postero-ventral spots of mesopleuron, scutellum except for a median black spot, postscutellum, posterior spot of metapleuron, a pair of antero-lateral spots of propodeum, and a posterior triangle marking of propodeum yellow. Scutellum sometimes entirely yellow. Metasomal tergites black except for a pair of basal spots of T I and posterior margins of T I to T III yellow to ivory. Posterior margins of T IV sometimes tinged with yellow. Membranous parts of metasomal sternites largely yellow. Subgenital plate blackish-brown, usually partly tinged with yellowish-brown. Ovipositor reddish-brown. Wings hyaline.Apical clouded area of fore wing slightly to weakly present. Veins and pterostigma blackish-brown except for yellowish-brown wing base. Fore and mid legs yellow; mid coxa partly tinged with blackish-brown basally. Hind coxa black except for a dorsal spot and apex yellow to yellowish-brown. Hind trochanter black to blackish-brown. Hind trochantellus reddish-yellow. Hind femur reddish-brown except for apex tinged with yellow. Hind tibia and tibial spurs yellowish-brown to whitish-brown except for apical part of tibia blackish-brown. Hind tarsus brown, partly tinged with yellow.
Male (n = 3). Similar to female (Figs 23 A–D). A male with body length 8.5 mm. Malar space 0.9 × as long as basal mandibular width. Tergal spiracles enlarged and with circular felt-like area, its length less than 0.2× as long as T I (Figs 2 R, S, 23 D). Basal part of T I punctate laterally (Fig. 2 S). Hind femur 5.3–6.3 × as long as maximum depth in lateral view. T I 2.4–2.8 × as long as maximum width. T II 1.7–2.05 × as long as maximum width. Yellow area of body larger than female. Face yellow except for a small median longitudinal spot. Two yellow spots of mesopleuron united into a single C-shaped marking. Posterior segments of metasoma tinged with reddish-brown.
Distribution. Japan (Hokkaido, Honshu, Shikoku, and Kyushu).
Etymology. The specific name is from old name of Japan “Yamato”.
Bionomics. Unknown.
Remarks. This species is closely related to S. flavitarsis sp. nov. Both species were collected same locality (Yamagata Pref., Mamurogawa Vil.) on same day. This species can be distinguished by the punctures on upper part of mesopleuron which are irregular and sparser than lower part (same density in S. flavitarsis) and the first to fourth hind tarsomeres usually more or less darkened (ivory in S. flavitarsis). In the key provided by Riedel (2021), the females and males runs to couplet 47 (female of S. dusmeti) and 7 (male of S. dusmeti), but differs by the antenna with 42–44 flagellomeres (38–40 flagellomeres in female of S. dusmeti), the malar space 0.5–0.6 × as long as basal mandibular width (0.7 in female of S. dusmeti), the median part of face largely black (largely yellow in female of S. dusmeti), the yellow markings of frons and vertex narrower than S. dusmeti, and the hind coxa black with yellow apical marking(s) (yellow with black spot in the male of S. dusmeti).
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 67-70, DOI: 10.11646/zootaxa.5496.1.2, http://zenodo.org/record/13331013