Diognetus styrax, 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 : 52

Diognetus styrax sp. nov.

( Figs 3D–F , 19C–D , 21A–C , 22E–F , 34J–O , 36M–N )

Type material. HOLOTYPE: J, TAIWAN: NANTOU HSIEN: Huiseun Forest Area, along Guandao-xi, 24.0865, 121.0265, sweeping inflorescence of Styrax suberifolia, 14 Mar 2017, T. Yasunaga ( NMNS) ( AMNH _ PBI 00380755 ) . PARATYPE: TAIWAN: Same data as for holotype, 1 ♀ ( TYCN).

Additional material examined. Same data, 5th instar nymph ( TYCN).

Description. Body oval (♀, Fig. 3E ) or elongate ovoid, subparallel-sided (J, Figs 19C–D ), moderate in size, 5.5– 5.7 mm. COLORATION: Basic coloration reddish-brown, with mottled pattern ( Figs 3E , 19C ). Head shiny, pale brown; clypeus darkened. Antennae pale reddish-brown; apex of segment II, segment III (except for pale extreme base) and segment IV dark brown. Labium pale brown, partly tinged with red; apical half of segment IV darkened. Pronotum reddish-brown, with posterior half darkened and posterior margin pale brown; mesal part of mesoscutum and anteromedial scutellum narrowly infuscate; pleura broadly fuscous; propleuron brown; scent efferent system creamy yellow. Hemelytron reddish-brown, speckled with dark maculae; cuneus slightly tinged with red; membrane smoky brown, with pale veins and some transparent maculae. Coxae and legs yellowish brown; pro- and mesofemora each with two obscure rings subapically; apical half of metafemur dark brown, with two pale rings subapically. Ventral surface of abdomen pale brown, mottled with darker maculae ( Fig. 19D ). SURFACE AND VESTITURE: As in generic diagnosis; dorsal surface weakly shining; punctures on pronotum and propleuron uniformly distributed; mesoscutum and scutellum pruinosed ( Fig. 34M ); scutellum shallowly and transversely rugose; hemelytron weakly shining, minutely pruinosed. STRUCTURE: Eyes large; vertex narrow. Antennal segment II about as long as labium. Labium slightly exceeding apex of mesocoxa but not reaching apex of metacoxa. Scutellum flat ( Fig. 34K ). Metathoracic scent efferent system as in Fig. 34L . Metatarsomere III about twice as long as I, slightly longer than II. MALE GENITALIA ( Figs 21A–C , 34O ): Left paramere with round-edged protuberance on sensory lobe and relatively broad hypophysis that is hooked at apex ( Fig. 21A ). Vesica with long LS and weak TP ( Fig. 21C ). FEMALE GENITALIA ( Figs 22E–F ): Some structures were not confirmed, due to teneral specimen. Posterior wall ( Fig. 22E ) with rather widened dorsal structure and moderate-sized interramal lobe.

Measurements. See Table 1.

Differential diagnosis. Based on the similarity in external appearance and genitalic structures, the present new species is considered as a closest relative of D. cheimon sp. nov. ( Japan) or D. dhampus sp. nov. ( Nepal), from which D. styrax sp. nov. can be distinguished by the following combination of characters: Vertex narrower in J; antennal segment II about as long as labium; protuberance on sensory lobe of left paramere rather rounded, less produced; surfaces of scutellum and hemelytron pruinosed, more sparsely punctate; shorter vesical MS; and interramal lobe wider, more rounded. The final instar nymph ( Fig. 3F ) is at first sight similar to two Japanese congeners, D. cheimon

sp. nov. and D. vernus sp. nov. (cf. Fig. 5 ); distinguished from them by generally lemon-yellow coloration, a pair of dark small spots on anterior wingpads, sparser vestiture on dorsum (cf. Fig. 36K vs. 36N), faint dark spots on each tibia and orange-pink spots scattered on abdominal sterna.

Etymology. Named for the generic name of the breeding host, Styrax formosanus; noun in apposition.

Biology. A pair of adults ( Figs 3D–E ) and a final instar nymph ( Fig. 3F ) were found to co-occur on the inflorescence of Styrax formosanus Matsum. ( Styracaceae ) ( Fig. 1I ) in central montane area of Taiwan.

Distribution. Taiwan (Nantou).

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.19. Habitus images of Diognetus spp.A−B − D. schuhorum sp. nov., holotypeJ, dorsal (A) and ventral (B) views; C−D − D. styrax sp. nov., holotype J; E–F – D. yamato nom. nov., J. Scale bars 2 mm.

Fig. 21. Male genitalia of Diognetus styrax sp. nov. (A−C), D. vernus sp. nov. (D−G) and D. yamato nom. nov. (H−J). A, D, H − left paramere; B, E, I − right paramere; C, F−G, J − vesica (endosoma). Scale bars 0.2 mm.

Fig. 22. Female genitalia of Diognetus pilosus (Poppius, 1914) (A–B – 00419636 from Sumatra, C–D – from Malaysia), D. styrax sp. nov. (E−F), D. vernus sp. nov. (G−I) and D. yamato nom. nov.(J−L). A, C, H, K − genital chamber. B, D, E, G, J − posterior wall; F, I, L − ovipositor (gonapophysis I); Scale bars 0.1 mm.

Fig. 34. Scanning electron micrographs for Diognetus puspae sp. nov.,J (A−F), D.schuhorum sp. nov., holotypeJ (G−I), and D.styrax sp. nov., holotype J (J, L, M−O) and ♀ (K). A, G, J, K − anterior body, left lateral view; B, L − pleura and scent efferent system, left lateral view; C, N − metatarsus; D − left paramere; E − right paramere; F − vesica (endosoma); H − apex of labium; I − apex of pygophore with parameres, left lateral view; M − scutellum and adjacent structures, left lateral view; N − metatarsus; O − pygophore, left lateral view.

Fig. 36. Scanning electron micrographs for Diognetus yamato Yasunaga nom. nov. from Shikoku, Japan (A−I), J (A−F) and ♀ (G−I), and immature forms of D. cheimon sp. nov. from Nagasaki, Japan (J−L), D. styrax sp. nov. from Nantou, Taiwan (M−N) and D. vernus sp. nov. from Nagasaki (O). A − anterior body, left lateral view; B − apex of labium with mandibular and maxillary stylets; C − pleura and scent efferent system, left lateral view; D − metatarsus; E, L − pretarsal structure of metaleg; F − apex of pygophore with parameres, left lateral view; G − posterior wall; H − dorsal structure and interramal lobe; I − apex of ovipositor (gonapophysis I); J − 5th instar exuvia, right lateral view; K − 5th instar thorax and abdomen, dorsal view; M − 5th instar nymph, anterior body; N − same, dorsal habitus; O − 5th instar exuvia, dorsal view.

Fig. 5. Late instar immature forms and eclosion (E−H, L−M) of Diognetus cheimon sp. nov. (A−H) and D. vernus sp. nov. (I−M), observed in Nagasaki, Japan (A, J−K on Eurya japonica and B−C on E. emerginata). A − yellow-green form of 4th (left) and 5th instars; B−C − reddish form of 5th instar; D − 4 anal spots of 5th instar; E − 5th instar nymph (3 hours before eclosion, with pigmented wing-pads); F−H − emerging ♀; I − yellow-green form of 5th instar; J−K − reddish form of 5th instar; L−M − emerging ♀.

Fig. 1. Habitats and host plants, Japan (A−F), Nepal (G−H) and Taiwan (I) for Diognetus cheimon sp. nov. (A−F), D. laureus sp. nov. (A−F), D. vernus sp. nov. (A−F), D. bagmaticus sp. nov. (G), D. puspae sp. nov. (H) and D. styrax sp. nov. (I). A–C − Eurya emarginata at preserved wetland (A), house entrance (B) and seaside park (C) in Nagasaki; D − Machilus thunbergii at Satoyama zone in Nagasaki City; E−F − Castanopsis sieboldii at coastal zones in Nagasaki City; G − Quercus semecaprifolia, inflorescence, at Nagarjun, Kathmandu; H − flowers of Schima wallichii at Godawari Valley, Lalitpur; I − Styrax formosanus, flowers, in Nantou.