Homotropus japonicum, Morishita & Watanabe, 2025

Morishita, Shunsuke & Watanabe, Kyohei, 2025, Review of the genera Homotropus Förster and Syrphoctonus Förster (Hymenoptera, Ichneumonidae, Diplazontinae) from Japan, Zootaxa 5588 (1), pp. 49-76 : 61-62

Homotropus japonicum sp. nov.

( Figs 7 A–C )

Type series. Holotype: F, JAPAN, Honshu, Nagano Pref., Otaki Vil., Mt. Ontakesan , 25 VI–15 VII 2015, S. Shimizu leg. ( MT) ( KPMNH) . Paratypes: JAPAN: [Honshu] 1F, Toyama Pref., Toyama City, Arimine, Inonedani , 14–21 IX 2009, M. Watanabe leg. ( MT) ( KPMNH) ; 1F, Toyama Pref., Nanto City, Togamura, Kamimomose , 15–29 IX 2009, M. Watanabe leg. ( MT) ( KPMNH) ; 1F, Ishikawa Pref., Hakusan City, Yahata , 7–24 X 2009, H. Fukutomi leg. ( MT) ( MU) .

Diagnosis. Antenna with 21–23 flagellomeres. Face coriaceous and matt; densely punctate. Clypeus depressed apically; robes weakly angulated at outer corners. Mesoscutum coriaceous and polished; densely punctate. Mesopleuron smooth and polished; densely punctate except for on and below speculum. Propodeum finely rugulose; posterior part of lateromedian longitudinal carina and pleural carina present. Fore wing length 6.5–8.5 mm. Areolet present. Dorsal part of hind coxa coriaceous and polished. Metasoma dorsoventrally depressed. Latero-median carina absent. T I 0.9–1.1 × as long as maximum width; finely rugulose laterally; otherwise coriaceous. T II 0.6– 0.7 × as long as maximum width. Face without pair of yellow markings along each inner orbits ( Fig. 7 B ). Face black with a small yellow median marking which separated from clypeus ( Fig. 7 B ). Clypeus entirely yellow to brown ( Fig. 7 B ). Malar space entirely black ( Fig. 7 B ). Yellow shoulder markings of mesoscutum present ( Fig. 7 A ). Scutellum black with yellow apical marking. All coxae entirely black ( Fig. 7 A ). Hind tibia black with white subbasal marking or band ( Fig. 7 C ). Metasoma entirely black.

Description. Female (n=4). Body covered with silverly setae; length 7.5–10.5 (holotype: 10.5) mm.

Head 0.5–0.53 (holotype: 0.52) × as long as wide in dorsal view; coriaceous and densely punctate. Clypeus 1.8–2.1 (holotype: 2.1) × as maximum width as high; sparsely punctate; depressed apically; robes weakly angulate at outer corners. Face 1.9–2.1 (holotype: 2.0) × as maximum width as high; weakly convex medially in lateral view; separated from clypeus by shallow clypeal sulcus. Malar space 0.66–0.75 (holotype: 0.72) × as long as basal mandibular width. POL 1.9–2.1 (holotype: 1.9) × as OD. OOL 1.4–1.6 (holotype: 1.4) × as OD. POL 1.36–1.45 (holotype: 1.36) × as long as OOL. Antenna with 21–23 (holotype: 21) flagellomeres. FL I 1.33–1.5 (holotype: 1.4) × as long as FL II . Maxillary palp IV1.0–1.1 (holotype: 1.1) × as long as Maxillary palp V .

Mesosoma densely punctate. Lateral aspect of pronotum rugulose anteriorly. Mesopleuron smooth below speculum. Sternaulus weakly impressed. Propodeum finely rugulose; posterior part of lateromedian longitudinal carina and pleural carina present. Fore wing length 6.5–8.5 (holotype: 8.5) mm. Areolet present. Vein 1cu-a of fore wing postfurcal or interstitial to vein M&RS. Hind wing with nervellus intercepted below middle. Hind wing with 8–10 (holotype: 8) distal hamuli. Dorsal part of hind coxa coriaceous and polished. Hind femur 3.7–4.0 (holotype: 4.0) × as long as maximum depth in lateral view. Hind tibia 6.2–6.6 (holotype: 6.6) × as long as maximum depth in lateral view. Ratio of length of hind first to fifth tarsomeres 1.0: 0.55–0.6 (holotype: 0.6): 0.4: 0.2–0.25 (holotype: 0.24): 0.3.

Metasoma coriaceous; dorsoventrally depressed. T I rectangular in dorsal view; 0.9–1.1 (holotype: 1.05) × as long as maximum width; finely rugulose laterally; latero-median carina absent. T II 0.6–0.7 (holotype: 0.66) × as long as maximum width; striate anteriorly.

Coloration ( Figs 7 A–C ). Body (excluding wings and legs) black. Face with small yellow marking medially. Mandible except for apex and base yellow. Clypeus yellow to brown. Antenna blackish-brown. Tegula brown to blackish-brown. Yellow shoulder markings of mesoscutum present. Legs black. Apex of fore and mid trochanters yellow. Fore and mid trochantelli, femora, tibiae, and tarsomeres yellowish-brown to brown. Hind trochanter yellowish-brown apically. Apex of hind trochantellus and base of hind femur reddish-brown. Hind tibia with white subbasal marking or band.

Male. Unknown.

Distribution. Japan (Honshu).

Bionomics. Unknown.

Etymology. The species name is from Japan.

Remarks. This species resembles H. sundevalli in the mesopleuron with dense punctures except for on and below speculum, the yellow shoulder markings present, the scutellum with yellow marking, and the entirely black metasoma, but can be distinguished from the latter by the following combination of character states: propodeum finely rugulose (coarsely rugulose in H. sundevalli ); latero-median carina of T I absent (present in H. sundevalli ); T I 0.9–1.1 × as long as maximum width (1.1–1.4 in H. sundevalli ).

Figures

FIGURE 7. Homotropus japonicum sp. nov., female―A: lateral habitus; B: head, frontal view; C: hind tibia, lateral view.