Diognetus flavigenis ( Horváth, 1905 ) Yasunaga & Schwartz & Chérot, 2023

Yasunaga, Tomohide, Schwartz, Michael D. & Chérot, Frédéric, 2023, Revision of the plant bug genus Diognetus, with descriptions of thirteen new species from the Oriental and Eastern Palearctic Regions (Hemiptera: Heteroptera: Miridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 63 (1), pp. 1-55 : 15-18

Diognetus flavigenis ( Horváth, 1905) comb. nov.

( Figs 3A–B , 7L–M , 11 , 28 )

Lygus flavigenis Horváth, 1905: 419 (original description).

Lygus flavigenis: LINNAVUORI (1965) : 269 (diagnosis).

Pinalitus flavigenis: KERZHNER (1988) :70 (new combination); MIYAMOTO & YASUNAGA (1989): 161 (faunal list).

Yamatolygus flavigenis: YASUNAGA (1994) : 123 (new combination, redescription); SCHUH (1995): 972 (catalog); KERZHNER & JOSIFOV (1999):182 (catalog); YASUNAGA (2001):268 (diagnosis), fig. 316 [color image wrongly showing D. vernus sp. nov.]; SCHUH (2002 –2013) (online catalog); AUKEMA (2018) (online catalog).

Type material examined. SYNTYPES (?): 1J 1♀ ( EIHU; without USIs),

JAPAN: HONSHU: Gifu Pref., 13 Jul (no further data provided).We could not access the type series preserved in HNHM, but a couple of specimens from Gifu, Japan, deposited in Hokkaido University Entomological Collection, Sapporo, Japan are considered as syntypes (cf. YASUNAGA 1994).

Additional material examined. JAPAN: HONSHU: Wakayama Pref., Kumano area, Hatenashi Mts., Mt.Ando, 1,100 m alt., 33.8977 135.6200, UV lighting, 7 Jun 2000, S. Gotoh, 1J 1♀ ( AMNH _ PBI 00419456–57) ( CNC), 10 JJ 8 ♀♀ without USIs ( TYCN); Wakayama Pref., Tanabe City (previous Ohtoh Village), Mengawa, Sampo Shinto Shrine, Kumano River, 33.689689, 135.595353, sweeping flowers of Cleyera japonica Thunb. , 15 Jun 1998, T. Yasunaga & S. Gotoh, 3 JJ 3 ♀♀ ( TYCN).

Redescription. See YASUNAGA (1994). Measurements. See Table 1.

Differential diagnosis. Recognized by the following characters: body generally chocolate brown, ovoid, rather tumid; dorsum speckled with paler maculae or spots ( Figs 3A–B ); head with yellowish brown jugum contrasting to dark clypeus (tylus) ( Fig. 7M ); labium short, reaching but not exceeding apex of mesocoxa ( Fig. 28A ); apex of scutellum creamy yellow; dark reddish-brown metafemur with creamy yellow basal half; parempodia rather broad and long ( Figs 28G− H ); left paramere with sensory lobe triangularly inflated ( Fig. 11B ) and thick hypophysis ( Fig. 28I ); vesical RS with an apical pointed process that is notched basally ( Fig. 11D ); sclerotized ring thick-rimmed ( Figs 11G , 28O ); dorsal structure of posterior wall rounded, wide, toothed ( Figs 28K− L ); and interramal lobe with uniformly distributed, comb-like scaly microstructures ( Fig. 28N ).

Biology. Occurrence of Diognetus flavigenis is, thus far as known, restricted to central and western Honshu (Tokai and Kinki areas). One of the breeding hosts appears to be Cleyera japonica Thunb. (Pentaphylacaceae) ; several fresh adults were found on the flower buds and inflorescence. A univoltine life cycle is assumed for this mirid. The adults were found in June and July and the eggs presumably hibernate.

Distribution. Japan (central and western Honshu).

Comments. This Japanese-indigenous species was described by HORVÁTH (1905), based on at least three syntypes, a couple of male specimens from Gifu, central Honshu and a female from Sapporo, Hokkaido ( AUKEMA 2018). LINNA- VUORI (1965) redescribed the female syntype (with label data as Japan, Sapporo, Matsumura) which however does not match the acceptable concept of Diognetus flavigenis and most probably fits Salignus duplicatus (Reuter, 1906) , judging from the redescription. This willow-inhabiting mirid is commonly found throughout Hokkaido (TODO & YASUNAGA 1995, YASUNAGA 2001), whereas D. flavigenis is now assumed to inhabit restricted areas in central and western Honshu including Gifu. Therefore, the type-series of ‘ flavigenis ’ (partim in HNHM) could include two species, and further verification and lectotype designation are required.

As mentioned above, we could access 1J 1♀ specimens from Gifu, deposited in Hokkaido University, Sapporo (namely, Matsumura Collection, the oldest insect collection in Japan). These are presumed to be a series of material that were collected along with the syntype male (from Gifu, HNHM) or can be included in the type-series, although HORVÁTH (1905) did not state in the original description how many specimens were designated as type-series.

Figures

Fig. 3. Habitus images for Diognetus species from Japan and Taiwan.A–B – D. flavigenis (Horváth, 1905) (from Kumano, Wakayama), C – D. insulanus (Yasunaga, 1994) (from Okinawa), D–F – D. styrax sp. nov.,♀ (D–E) and 5th instar nymph (Nantou, Taiwan), G–H – D. yamato nom. nov. (from Kochi).

Fig. 7. Habitus images of Diognetus spp.A−C − D. bagmaticus sp. nov.,J (A−B) and♀ (C); D – undeterminedJ specimen from Queensland,Australia; E−F − D. dhampus sp. nov.,J; G−H − D. duwalorum sp. nov., holotype J; I − D. giganteus sp. nov., holotype ♀; J−K − D. gotohi sp. nov., holotype J; L−N − D. flavigenis (Horváth, 1905), J (M − head in frontal view). Scale bar 2 mm.

Fig. 11. Male (A–E) and female (F–I) genitalia of Diognetus flavigenis (Horváth, 1905).A − right paramere; B−C − left paramere; D−E − vesica (endosoma); F − ovipositor (gonapophysis I); G−H − genital chamber; I − posterior wall. Scale bars 0.1 mm.

Fig. 28. Scanning electron micrographs for Diognetus flavigenis (Horváth, 1905) from Honshu, Japan, J (A, C−H) and ♀ (B, K−P). A – left lateral habitus; B − dorsal habitus; C − scutellum and adjacent structures; D − head and pronotum, anterior view; E − pleura and scent efferent system, left lateral view; F − metatarsus; G−H − pretarsal structure of metaleg; I − left paramere; J − right paramere; K − posterior wall; L − dorsal structure; M − dorsal structure and interramal lobe; N − interramal lobe; O − sclerotized ring; P − apex of ovipositor (gonapophysis I).