Diognetus laureus, 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 : 27-28

Diognetus laureus sp. nov.

( Figs 1D , 10H–K , 12G− I , 13 , 23 , 30J− O , 31 ) Yamatolygus sp. 1 : MIYAZAKI et al. (2020): 66, table 1 (life span, Japanese name).

Type material. HOLOTYPE: J, JAPAN: KYUSHU: Nagasaki Pref., Nagasaki City, Yotsue-machi, Agri-Hills Park, 32.809700, 129.797000, sweeping fruits of Machilus thunbergii Siebold et Zucc. (Lauraceae) , 25 Jun 2019, T. Yasunaga ( AMNH) ( AMNH _ PBI 00380751). PARATYPES: JAPAN: KYUSHU: Fukuoka Pref., Yame City, Mt. Shakadake, 33.20, 130.84, UV lighting, 6 Jul 2019, 1 ♀, T. Nozaki ( WCF); Nagasaki Pref., Nagasaki City,Tateyama, Mt.Konpira, sweeping flower buds of Eurya japonica , 32.764888, 129.879500, 24 Dec 2021, T.Yasunaga, 1♀ ( TYCN); Nagasaki City, Nomozaki, Kabashima Island, 32.556555, 129.777977, sweeping fruits of Machilus thunbergii , 1 Jun 2019, T. Yasunaga, 1 J [4th instar immature form reared then emerging on Jun 5, 2019, and mounted on Jun 16] ( TYCN); same data, except for date, 6 Jun 2021, T. Yasunaga, 1 J 3 ♀♀ ( TYCN); same data, from 32.556161, 129.778000, inflorescence of Cinnamomum japonicum Sieb. , 6 Jun 2021, T.Yasunaga, 1 ♀ [5th instar immature form reared then emerging on same day and dead on Jun 12] ( TYCN); Nagasaki Pref., same data as for holotype, 2 JJ 2 ♀♀ ( TYCN); Nagasaki City,Iojima Island (lighthouse-park), 32.714177, 129.761155, sweeping flowers and fruits of Eurya emarginata , 27 Dec 2019, T. Yasunaga & K. Tanaka, 1 ♀ [5th instar immature form reared then emerging on Jan 1, 2020] ( TYCN); Nagasaki City, Tateyama; Mt. Konpira, 32.765247, 129.877073, sweeping flowers and fruits of Machilus thunbergii , 19 Jun 2021, T. Yasunaga, 6 JJ ( CNC, TYCN); same data, except for detailed collecting site, 32.7640, 129.8787, 1 ♀ ( TYCN); Nagasaki Pref., Omura City, Kushima, Ryujin Island (Shrine), 32.895166, 129.952900, on flower of evergreen broadleaf, 4 Jul 2022, T.Yasunaga, 1 J ( TYCN). SHIKOKU: Kochi Pref., Otoyo Town, Osugi, 33.76, 133.66, on Ternstroemia gymnanthera (Wight &Arn.) Bedd. (Pentaphylacaceae) , 14 Jul 2004, M. Takai, 1 ♀ ( TYCN); Tosa-Shimizu City, Cape Ashizuri, 32.73, 133.00, 22 May 1999, T. Befu, 1 J ( TYCN).

Additional material examined (teneral specimens): JAPAN: KYUSHU: Kumamoto Pref., Amakusa City, Uonuki Town, 32.256, 129.999, UV lighting, 12 Jun 2015, T. Nozaki, 1 ♀ ( WCF); Nagasaki Pref., Nagasaki City, Kabashima Island, from 32.556161, 129.778000, inflorescence of Cinnamomum japonicum Sieb. , 6 Jun 2021, T. Yasunaga, 1 ♀ [5th instar immature form reared then emerging on Jun 9 and dead on Jun

12] ( TYCN); same locality and plant as for holotype, 6 Jun 2021, T. Yasunaga, 2 JJ [5th instar immature form reared then emerging on Jun 10–11 and dead on Jun 15, Jun 20] ( TYCN).

Description. Body elongate ovoid, relatively small, 4.2–5.1 mm in total length. COLORATION: Body including ventral surface generally pale reddish-brown ( Figs 13A− C, E ) (fresh specimens often bright red, cf. Fig. 13D ); dorsum without mottled pattern. Antennae pale reddish-brown; segment I red or reddish-brown; apex of segment II uniformly pale, partly tinged with red; segment III (except for pale extreme base) and segment IV brown. Labium pale reddish-brown; apex of segment IV infuscate ( Fig. 13E ). Pronotum usually brown posteriorly, with yellowish posterior margin; calli often with a pair of dark, small spots; pleura broadly reddish-brown; scent efferent system creamy yellow. Hemelytron almost uniformly pale reddish-brown, without dark maculae; membrane pale smoky brown, with pale veins and several semitransparent spots ( Figs 13A− B ). Coxae and legs reddish-brown; mesofemur with two faint pale rings subapically ( Fig. 13E ); tarsi brown; apical part of each tarsomere III brown. Ventral surface of abdomen reddish-brown, with paler median part. SURFACE AND VESTITURE: As in generic diagnosis; dorsal surface weakly shining, with densely distributed, brown, simple, semierect setae and silvery, reclining setae ( Figs 23 , 30N ); scutellum transversely rugose, sparsely and finely punctate; hemelytron rather matte; punctures on corium partly very sparse or missing. STRUCTURE: Vertex with a basal transverse carina, weakly arched. Antennal segment II obviously shorter than labium. Labium long, exceeding apex of metacoxa and reaching abdominal sterna IV− VI ( Fig. 30J ), in J longer than maximum width across hemelytron. Scutellum rather flat. Metathoracic scent efferent system as in Fig. 30L . Metatarsomere II slightly longer than III; pretarsal structure as in Fig. 31B ; parempodia rather long and broad. MALE GENITALIA ( Figs 12G− I , 31C ): Pygophore generally small in size ( Fig. 31C ). Left paramere with relatively narrow protuberance of sensory lobe and somewhat tapered hypophysis that is hooked at apex ( Fig. 12G ); right paramere slender ( Fig. 12H ). Vesica small-sized, with MS and LS that are similar in shape and size; RS minutely and sparsely spinulate, with small TP ( Fig. 12I ). FEMALE GENITALIA ( Figs 10H− K , 31D− I ): Sclerotized ring thin-rimmed ( Figs 10H− I , 31G− H ); posterior wall ( Figs 10J , 31E− F ) with rather small dorsal structure; interramal lobe with rounded lateral margin ( Fig. 31E ); spines on dorsal structure smaller than interramal lobe ( Fig. 31F ).

Measurements. See Table 1.

Differential diagnosis. Recognized by its generally pale reddish-brown, relatively small-sized, elongate oval body; long labium that is surpassing apex of metacoxa and longer than maximum width in J; generally small male genitalia; and thin-rimmed sclerotized ring. Most closely related to D. insulanus , from which D. laureus sp. nov. can be distinguished by the generally smaller size, pale reddish-brown basic coloration, longer labium, narrower apical part of the protuberance of the left paramere, thinner-rimmed sclerotized ring, rather rounded lateral margin of the interramal lobe, and shorter spines on the dorsal structure.

The immature forms (3rd to 5th instars) are recognized by the following features: Body generally bright red, rounded or ovoid (sometimes partly tinged with olive as in Fig. 13G ); antenna long, longer than body in 4th−5th ( Figs 13F, I ); and dark spot (scent gland opening) on abdominal tergum III reddish, small. By these characters, the late immature forms of D. laureus sp. nov. can be distinguished from those of D. cheimon sp. nov. and D. vernus sp. nov. (cf. Fig. 5 ).

Etymology. Named for the plant association of this new species with Lauraceae hosts; an adjective.

Biology. This new species is associated with Lauraceae evergreen broadleaf trees (flowers and fruits), Machilus thunbergii Siebold & Zucc. ( Fig. 1D ) and Cinnamomum japonicum Sieb. , on which the immature forms were found in June. The reddish general coloration both in the adults and nymphs appears to be cryptic, harmonious with the red peduncles (cf. Figs 13C, I ). On the other hand, winter- -emerging population (possibly 2nd annual generation, cf. Table 2) was discovered from the flowers or fruits of Eurya emarginata (and 1 ♀ from E. japonica ) and often co-occurred with Diognetus cheimon sp. nov. and D. vernus sp. nov. These three mirids are closely related to each other and may be derived from a common ancestor that was associated with Eurya evergreen trees, although the spring− summer generation of each species utilizes different hosts.

Distribution. Japan (Shikoku, Kyushu).

Figures

Fig 13. Habitus images of adults (A−E) and immature forms (F−I) for Diognetus laureus sp. nov. A, C − male on Machilus thunbergii (C− holotype); B, E − female; D − male and exuvia (left); F − 4th instar nymph; G − 3rd (left) and 5th instar nymphs; H−I − 5th instar nymph.

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.

Fig. 10. Female genitalia of Diognetus bagmaticus sp. nov. (A−D), D. cheimon sp. nov. (E−G) and D. laureus sp. nov. (H−K). A, E − genital chamber; B, I − sclerotized ring; C, F, J − posterior wall; D, G, K − ovipositor (gonapophysis I). Scale bars 0.1 mm.

Fig. 12. Male genitalia of Diognetus gotohi sp. nov. (A−C), D. insulanus (Yasunaga, 1994) (D−F) and D. laureus sp. nov. (G−I).A, D, G − left paramere; B, E, H − right paramere; C, F, I − vesica (endosoma). Scale bars 0.2 mm.

Fig. 23. Dorsal vestiture pattern for 4 Japanese Diognetus species: D. cheimon sp. nov., D. insulanus (Yasunaga, 1994), D. laureus sp. nov and D. vernus sp. nov.

Fig. 30. Scanning electron micrographs for Diognetus intonsus Distant, 1904,♀ from Chiang Mai, Thailand (A−I) and D. laureus sp. nov.,J from Nagasaki, Japan (J−O). A, K − anterior body, left lateral view; J − left lateral habitus; B, L − scutellum and adjacent structures, left lateral view; C − head and anterior pronotum, dorsal view; D − scutellum and adjacent structures; E−F − metatarsus; G − sclerotized ring; H − posterior wall; I − dorsal structure and interramal lobe; M − dorsal habitus; N − corium; O − posterior corium and anterior cuneus.

Fig. 31. Scanning electron micrographs for Diognetus laureus sp. nov. from Nagasaki, Japan, J (A−C), ♀ (G−I), 4th instar nymph’s exuvia (J−L) and 5th instar’s exuvia, J (M−O). A − metatarsi; B − pretarsal structure of metaleg; C − apex of pygophore with parameres, left lateral view; D−E − posterior wall; F − dorsal structure and interramal lobe; G − genital chamber, dorsal view; H − sclerotized ring; I − apex of ovipositor (gonapophysis I); J, M − anterior body, right (J) and left (M) lateral view; K, N − compound eye; L, O − metatarsus.

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 ♀.