Diognetus cheimon, 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 : 12-15

Diognetus cheimon sp. nov.

( Figs 4 , 5A–H , 8E− G , 10E− G , 23 , 26 , 36J− L )

Type material. HOLOTYPE: J, JAPAN: KYUSHU: Nagasaki Pref., Nagasaki City, Kurosaki-Nagata Marsh (biotope), 32.829185, 129.721365, sweeping flowers of Eurya emarginata , 13 Dec 2020, T. Yasunaga ( AMNH _ PBI 00380745 ) ( AMNH) . PARATYPES: JAPAN: HONSHU: Chiba Pref., Matsudo City, 21 Century Forest Park, 35.807500, 139.938333, 9 Sep 2012, N. Muro ( TYCN). KYUSHU: Nagasaki Pref.: Nagasaki City, Iojima Island (lighthouse-park), 32.714177, 129.761155,sweeping flowers and fruits of Eurya emarginata , 27 Dec 2019, T. Yasunaga & K. Tanaka, 3 JJ 2 ♀♀ [1 J – 5th instar immature form reared then emerging on Jan 1, 2020] ( TYCN); Nagasaki City, Kabashima Island, 32.564877, 129.780177, sweeping flowers and fruits of Eurya japonica , 27 Dec 2019, T. Yasunaga, 2 JJ and 1 J [5th instar immature form reared then emerging on Dec 30, 2019] ( TYCN); Nagasaki City, Kurosaki-Nagata Marsh (biotope), 32.829185, 129.721365, sweeping flowers and fruits of Eurya emarginata , 15 Dec 2019, T. Yasunaga, 3 ♀♀ and 1 J [5th instar immature form reared then emerging on Dec 17, 2019, dead on Jan 2, 2020] ( TYCN); same locality and plant, 13 Dec 2020, T.Yasunaga, 3 ♀♀ ( TYCN) and 1 ♀ [5th instar immature form reared then emerging on Dec 15, 2020] ( TYCN); Nagasaki City, Sotome, Higashi-Shitsu, 32.835325, 129.702280, sweeping flowers of Eurya emarginata , 13 Dec 2020, T.Yasunaga, 1♀ ( TYCN); Nagasaki City,Konoura-Ohgiyama,Konoura Dam, 32.888, 129.722, UV lighting, 20 Mar 2016, T. Nozaki, 1 J ( TYCN), 1♀ ( WCF); same data, except for date 27 May 2016, 1 ♀ ( TYCN); Nagasaki City, Tateyama, Mt. Konpira, sweeping flower buds of Eurya japonica , 32.764888, 129.879500, 13 Nov 2021, T. Yasunaga, 1 ♀ ( TYCN); same data, except for date 24 Dec 2021, 1 J 2 ♀♀ ( TYCN); Nagasaki City, Takenokubo, Nagasaki West High School, 32.765877, 129.859789, inflorescence of Osmanthus heterophyllus , 9 Dec 2021, T. Yasunaga, 1 J 2 ♀♀ ( TYCN); Nagasaki City, Nameshi 2-24, 32.809253, 129.841743, on Eurya emarginata , 6 Dec 2020, T. Yasunaga, 1 J ( TYCN); Nagasaki City, Taira (Azekari, Fishery Port), 32.807615, 129.770780, sweeping flowers and fruits of Eurya emarginata , 6 Dec 2020, T. Yasunaga, 2 JJ 1 ♀ ( TYCN) and 1J 1 ♀ [5th instar immature form reared then emerging on Dec 8–10, 2020] ( TYCN); same locality and plant, 13 Dec 2020, 2 ♀♀ [5th instar immature form reared then emerging on Dec 18, 2020] ( TYCN); same locality and plant, 29 Nov 2021, 2 JJ 1 ♀ [4–5th instar immature form reared then emerging on Dec 1–7, 2021] ( TYCN); Nagasaki City, Kinkai-Tonehara, 32.900888, 129.795522, sweeping buds of Eurya japonica , 21 Jan 2020, T. Yasunaga, 1 ♀ [freshly emerged and dead on May 7, 2020] ( TYCN); Nishisonogi-gun,Togitsu-Nagayo, Sakino Nature Park, 32.854271, 129.854646, sweeping buds of Eurya japonica , 20 Dec 2020, T. Yasunaga, 1 J 1 ♀ and 1 ♀ [5th instar immature form reared then emerging on Dec 21, 2020] ( TYCN); same data, 1 J 1 ♀ [5th instar immature form reared then emerging on Dec 25 (J) / Dec 28 (♀), 2020 and dead on Apr 28, 2021] ( TYCN); Omura City, Kushima, 32.897077, 129.952977, sweeping flowers of Eurya emarginata , 15 Jan 2020, T.Yasunaga, 1J [5th instar immature form reared then emerging on Jan 21, 2020] ( TYCN); same locality and plant, 9 Dec 2020, T. Yasunaga, 2 ♀♀ [5th instar immature form reared then emerging on Dec 15–18, 2020] ( TYCN); same locality and plant, 23 Dec 2020, T. Yasunaga, 1 J ( TYCN); Saikai City,Ohseto Town, Fukushima,Shirikusari Beach, 32.925066, 129.640533 sweeping fruits of Eurya emarginata , 2 Jan 2020, T. M. & H. Yasunaga, 1 J; Saikai City, Oshima, Mt. Yuridake, 33.040, 129.608, UV lighting, 4 May 2016, T. Nozaki ( TYCN). SHIKOKU: Kochi Pref., Tosa-Shimizu City, Cape Ashizuri, 32.73, 133.00, UV lighting, 10 Apr 1999, T. Befu, 1 J 1 ♀ ( TYCN); Kochi Pref., Cape Muroto, Muroto Skyline Road [Rt 203], 33.25232, 134.17835, sweeping Eurya emarginata , 18 Dec 2019, M. Takai, 15 JJ 24 ♀♀ ( AMNH, CNC, NIAES, NMPC, TYCN); same locality, beating Eurya emarginata , 9 Dec 2000, T. Befu ( TYCN); Kochi Pref., Tosa City, Mt. Yokose-yama, 33.4693, 133.4377, UV lighting, 27 March 2000, T. Befu, 1 ♀ ( TYCN); Kochi Pref., Sukumo City, Nakasuji Dam, 32.9282, 132.8137, UV lighting, T. Befu, 1 ♀ ( TYCN).

Additional material examined. JAPAN: KYUSHU: Kumamoto Pref., Amakusa City, Tsuruha-yama Park, 32.15, 130.04, UV lighting, 18 Oct 2015, T. Nozaki, 3 JJ 2 ♀♀ (all teneral specimens, WCF).

Description. Body elongate ovoid, moderate to large in size, 4.8–6.1 mm. COLORATION: Dorsum varying from reddish-brown ( Fig. 4B ) to chocolate brown ( Fig. 4A ), usually with mottled pattern ( Figs 4A− C ). 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. Pronotum reddish-brown, with calli and posterior half sometimes darkened ( Fig. 4A ) and posterior margin narrowly pale; pleura broadly fuscous; scent efferent system creamy yellow. Hemelytron reddish-brown, usually speckled with dark maculae; apices of exocorium (embolium) and cuneus narrowly pale; membrane smoky brown, with yellowish veins. Coxae and legs yellowish brown; mesofemur with two faint dark rings subapically; apical 1/3 of metafemur dark brown, with two pale rings subapically. Ventral surface of abdomen pale brown (somewhat greenish when alive), with more or less darkened lateral margins ( Figs 4E− F ). SURFACE AND VESTITURE: As in generic diagnosis; dorsal surface weakly shining; scutellum transversely rugose; hemelytron rather matte. STRUCTURE: Vertex with a basal transverse carina weakly arched. Antennal segment I about as thick as pronotal collar, longer than segment IV. Labium slightly exceeding apex of mesocoxa but not reaching apex of metacoxa ( Figs 4E− F ). Scutellum rather flat, shallowly and sparsely punctate, with apex weakly produced ( Fig. 26D ). Metathoracic scent efferent system as in Fig. 26C . Metatarsomere I short, about half as long as III; pretarsal structure as in Figs 26F− G ; parempodia rather long. MALE GENITALIA ( Figs 8E− G 26H–K ): Left paramere with squared, developed sensory lobe and rather broad hypophysis that is hooked at apex ( Figs 8E , 26J ). Vesica with short, branched MS and smooth LS, lacking noticeable TP ( Figs 8G , 26K ). FEMALE GENITALIA ( Figs 10E− G , 26L− P ): Sclerotized ring with thickened anterior rim ( Figs 10E , 26L ); posterior wall ( Figs 10F , 26N− P ) with narrow dorsal structure and moderate-sized interramal lobe.

Measurements. See Table 1.

Differential diagnosis. Recognized by its relatively elongate, moderate to large body; short labium slightly surpassing apex of mesocoxa; generally long wings; and shape of the male and female genitalic structures described above. Most similar in external appearance to D. bagmaticus sp. nov.; distinguished by long antennal segment IV that is obviously longer than segment I, subapically constricted sensory lobe of left paramere ( Figs 8E , 26J ), short right paramere ( Fig. 26I ); vesica with elongate MS; and wider interramal lobe with comb-like scaly microstructures laterally ( Fig. 26P ).

The final instar nymph is recognized by the following characters (cf. Figs 5A–D, E ): Body ovoid, relatively large, 3.6–3.9 mm in length; basic coloration varying from pale greenish yellow ( Fig. 5A ) to reddish-brown ( Figs 5B, E ); dorsum sometimes with mottled pattern, with densely distributed, simple, semierect setae and rather sparsely distributed, dark, stiff, upright setae ( Figs 36J–K ); antenna and legs pale greenish yellow to reddish-brown, partly with small, dark spots; abdomen with reddish spots; scent gland opening on abdominal tergum III with semicircular spot; and anal ridge with 4 dark spots ( Fig. 5D ).

Measurements. See Table 1.

Etymology. From Greek, cheimon (winter), referring to its particular emergence in December and January; most of specimens were collected during this cold season ( Table 2). Noun in apposition.

Biology. The present new species was confirmed to be associated with Pentaphylacaceae evergreen broadleaf trees, Eurya emarginata (Thunb.) Makino and E. japonica Thunb. This winter-emerging mirid was predominantly found in December and January, when the inflorescences and fruits of the host trees were abundant ( Figs 1A− C ). Within recent years, the mirid has frequently been found in urbanized zones and residential areas of southwestern Japan, as Eurya emarginata is now planted everywhere for landscaping ( Fig. 1B ) and for house hedge ( Fig. 1C ). The mirid species appears to expand its habitat to artificial environment, utilizing such available host plants. On the other hand, Eurya japonica is also common in southern Japan and sometimes used for traditional religious (Shinto) ceremonies.

A univoltine or bivoltine life cycle is assumed for Diognetus cheimon sp. nov. (cf. Table 2). The first annual generation appears to emerge in autumn (September− October) and the second generation (late instar immature forms and adult) could hibernate. In Nagasaki area, western Kyushu, the adults emerging in winter (December− January) survived until April or May when reared carefully with the host leaves and fermented milk beverage (Yasunaga, pers. observ.). Like as Diognetus vernus sp. nov. (see below), the adults of D. cheimon sp. nov. were found to have long life span (107–124 days in J / 121 days in ♀). Several adults were recently found on inflorescence of a (Japanese) holly tree, Osmanthus heterophyllus (G.Don) P.S.Green (Oleaceae) , but no immature forms were confirmed.

Distribution. Japan (Honshu, Shikoku, Kyushu); habitats are restricted to warm temperate climatic zones where the breeding hosts grow.

Figures

Fig. 4. Habitus images of Diognetus cheimon sp.nov.(all from Nagasaki, Japan).A − J sucking on Eurya emarginata fruit; B − 5th instar nymph (left) and J on flower buds of Eurya japonica; C − ♀; D − J (left) and ♀ sucking on young fruits of E. japonica; E−F − ventral habitus images ofJ (E) and ♀ (F).

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. 8. Male genitalia of Diognetus bagmaticus sp. nov. (A−D), D.cheimon sp. nov.(E−G), D. dhampus sp. nov. (H−J) and D. duwalorum sp. nov.(K−M). A−B, E − apex of pygophore with parameres; C, H, L − right paramere; I, K − left paramere; D, F−G, J, M − vesica (endosoma). Scale bars 0.2 mm.

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. 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. 26. Scanning electron micrographs for Diognetus cheimon sp. nov.from Nagasaki, Japan,J (A−K) and♀ (L−P).A−B – left lateral habitus; C − pleura and scent efferent system, left lateral view; D − head and pronotum, left lateral view; D − anterior body, left lateral view; E − metatarsus; F−G − pretarsal structure of metaleg; H − apex of pygophore with exposed vesica and left paramere; I − right paramere; J − left paramere; K − vesica (endosoma); L − sclerotized ring; M − apex of ovipositor (gonapophysis I); N − posterior wall; O − dorsal structure; P − interramal lobe.

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. 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.