Itoigawacoris Yasunaga & Mashima, 2025

Yasunaga, Tomohide & Mashima, Gō, 2025, A new genus and species of mirine plant bug endemic to central Honshu, Japan, a region receiving the world’s heaviest snowfall (Insecta: Hemiptera: Heteroptera: Miridae: Mirinae: Mirini), Zootaxa 5716 (3), pp. 397-408 : 398-399

publication ID	https://doi.org/10.11646/zootaxa.5716.3.6
publication LSID	lsid:zoobank.org:pub:A7743C3B-3E22-4B26-BC2D-342C22BF7366
DOI	https://doi.org/10.5281/zenodo.17889482
persistent identifier	https://treatment.plazi.org/id/E26F781A-FFA1-6954-FF5A-145347326D72
treatment provided by	Plazi
scientific name	Itoigawacoris Yasunaga & Mashima
status	gen. nov.

Treatment

Genus Itoigawacoris Yasunaga & Mashima gen. nov.

Diagnosis. Distinguished from other superficially similar mirine taxa (e.g. Lygocoris Reuter, 1875 , Pinalitopsis Yasunaga, Schwartz & Chérot, 2002 or Pinalitus Kelton, 1955 ) by the following combination of characters: head shiny fuscous, rounded in front; eyes small; basal transverse carina of vertex weak; slender antenna with segment III entirely milky white, contrasting to darkened in other antennomeres; labium reaching but not exceeding apex of metacoxa; pronotum shallowly and uniformly punctate, with thick collar; scutellum almost flat, weakly arched; cuneus widely creamy white; tibial spines dark brown, short, sparsely distributed; pulvillus relatively thick; parempodium shorter than claw, in addition to distinct male and female genitalic structures ( Figs. 3A–E View FIGURE 3 , 5A–J View FIGURE 5 ). The generic characters and systematic position of the present new genus are discussed below.

Description. Body medium-sized ( 4.5–5.1 mm in total length, 1.5–1.7 mm in maximum width), elongate-ovoid, nearly parallel-sided, not sexually dimorphic in overall appearance and size ( Fig. 1A–B View FIGURE 1 ); dorsal surface relatively shining, with uniformly distributed, pale, simple, semierect setae ( Fig. 4A, E View FIGURE 4 ). Head: Shiny, polished, impunctate, vertical, with sparsely distributed, simple, short, upright setae ( Fig. 4C–D View FIGURE 4 ); eyes relatively small, slightly removed from anterior margin of pronotal collar; vertex and frons smooth, somewhat bulbous; basal transverse carina of vertex weak, faint ( Fig. 4C View FIGURE 4 ). Antenna: Generally slender, slightly shorter than body; segment I about 2/3 as long as IV; segment II almost linear, not clavate, longer than basal width of pronotum; remaining segments filiform; segment III entirely milky white, contrasting to darkened other antennomeres. Labium: Reaching but not exceeding apex of metacoxa, longer than metafemur. Pronotum: Totally shiny fuscous, shallowly and uniformly punctate, with uniformly distributed, pale, semierect setae; pronotal collar pale creamy brown, more or less tinged with red in fresh specimens, with somewhat shagreened surface ( Fig. 4C View FIGURE 4 ), almost equal in thickness to antennomere I; scutellum smooth, weakly arched ( Fig. 4E View FIGURE 4 ); metathoracic scent efferent system as in Fig. 4F View FIGURE 4 , with relatively narrow peritreme. Hemelytra: Weakly shining, reddish to dark brown, faintly punctate, composed of rather delicate integument, with uniformly distributed, pale semierect setae; cuneus widely creamy white; membrane about twice as long as cuneus. Legs: Relatively long; metaleg (femur + tibia + tarsus) slightly shorter than body length: tibial spines dark brown, short, weak, sparsely distributed; each tibia lacking dark spot at base of each spine; tarsi generally slender; metatarsus with shortest tarsomere I; meta-tarsomere II as long as III ( Fig. 4G View FIGURE 4 ); pretarsal structure of metaleg as in Fig. 4H–I View FIGURE 4 ; pulvillus relatively thick; parempodium shorter than claw. Male genitalia ( Figs. 3A–B View FIGURE 3 , 5A–F View FIGURE 5 ): Left paramere basally with stout, triangularly produced sensory lobe ( Fig. 5C View FIGURE 5 ); right paramere with hooked hypophysis ( Fig. 5D View FIGURE 5 ). Vesica widely furnished with spinules and a single, stout spicule that is serrate basally and tapered apically ( Fig. 3B View FIGURE 3 , 5F View FIGURE 5 ); phallotheca wrinkled ( Fig. 5F View FIGURE 5 ), lacking process. Female genitalia ( Figs. 3C–E View FIGURE 3 , 5G–J View FIGURE 5 ): Genital chamber with a pair of distinct sclerotized edges of dorsal labiate plate ( Figs. 3C View FIGURE 3 , 5G View FIGURE 5 ); sclerotized rings with thickened anterior margin, separated from each other mesally ( Figs. 3C View FIGURE 3 , 5G View FIGURE 5 ); margin of ovipositor (gonapophysis I) minutely serrate ( Fig. 3D View FIGURE 3 ). Posterior wall with lateral lobe and interramal lobe, lacking noticeable dorsal structure ( Fig. 3E View FIGURE 3 , 5H–I View FIGURE 5 ); lateral lobe with scaly microstructures and interramal lobe spinulate ( Fig. 5J View FIGURE 5 ).

Type species: Itoigawacoris venustulus Yasunaga & Mashima , new species, by original designation.

Remarks. This new genus belongs to a traditionally confused group, so-called ‘ Lygus -complex’ (cf. Chérot et al. 2025). Recent efforts by the first author and his colleagues have attempted to provide proper classification system for this garbage-group (e.g. Yasunaga et al. 2002, 2018a, 2023a, Yasunaga & Schwartz 2016, Yasunaga 2024a, b). Nonetheless, further cryptic taxa, like as Itoigawacoris , are remaining undescribed in Asia-Oriental.

The late instar (4–5th) immature forms of the present new species, Itoigawacoris venustulus , have unusual microstructures on the head (e.g. Fig. 6B–C View FIGURE 6 ). However, we currently cannot regard these structures as a generic character, as such microstructures in the plant bug nymphs have not been observed. The structures are currently considered to function as a gland or certain sense organ. Further physiological examination is required to verify the actual function.