Two new unique hibiscus-inhabiting species of the plant bug genus Sejanus Distant from Japan and Taiwan (Hemiptera: Heteroptera: Miridae: Phylinae) Author Yasunaga, Tomohide Research Associate, Division of Invertebrate Zoology, American Museum of Natural History, Central Park at 79 th Street, New York, NY 10024, c / o Nameshi 2 - 33 - 2, Nagasaki 852 - 8061, Japan. Author Duwal, Ram Keshari 0000-0002-2068-461X Visiting Researcher, Agriculture & Agri-Food Canada Environmental Health, K. W. Neatby: Bldg # 20, 960 Carling Avenue, Central Experimental Farm, Ottawa Ontario, Canada K 1 A 0 C 6. ramkeshariduwal @ gmail. com; https: // orcid. org / 0000 - 0002 - 2068 - 461 X ramkeshariduwal@gmail.com text Zootaxa 2022 2022-12-19 5222 2 155 167 journal article 53777 10.11646/zootaxa.5222.2.4 c60dc4ba-6d53-4a47-9460-80703bcfedce 1175-5326 7456681 55F69A43-2837-4E5F-936D-5ADD23BA5790 Sejanus epicurus n. sp. ( Figs. 1A–J ; 2I–J ; 4A–D ; 5A–G ; 6A–F ; 7A–D ) Material examined. Holotype (♁). TAIWAN : Pingtung Co., Manchu [Boánchiu], branch of Chunggang stream, near north border of Mt. Nanren , 22°06'17.0"N 120°51'24.3"E , 60 m alt., Hibiscus taiwanensis , 20 Mar 2017 , T. Yasunaga et al . ( NMNS ) ( AMNH _ PBI 00380760 ) . Paratypes : TAIWAN : Same data as for holotype, 43♁ 43♀ ( AMNH , CNC , TYCN ) ; Pingtung Co., Mudan Township , Shimen Village , Cacevakan (historic ruin), 22°06'34.9"N 120°48'06.1"E , 200 m alt., Hibiscus taiwanensis , 16 Mar 2017 , T. Yasunaga et al ., 19♁ 17♀ ( CNC , NMNS , TYCN ) ; Pingtung Co., Manchu , Lite Village , Xilaikou stream, 22°00'48.5"N 120°52'39.2"E , 20 m alt., Hibiscus taiwanensis , 21 Mar 2017 , T. Yasunaga ( TYCN ) . Diagnosis. Readily recognized by its small size; relatively fragile surface structure; creamy yellow antenna, with darkened apical 1/4 of segment II; shiny black hemelytra with white base of cuneus ( Fig. 1H–J ); and almost totally creamy yellow legs ( Fig. 2I–J ). Any other known congeners with fuscous dorsum have more or less darkened femora. FIGURE 2. Habitat (A–C), and habitus images of Sejanus ryujin n. sp. (D–H) and S. epicurus n. sp. (I–J), and Orius strigicollis (Poppius) (5th instar nymph) and an undetermined thrips sharing same niche (K); G–I showing ventral view of fresh specimens. A–C. Hibiscus hamabo , breeding host of S, ryujin n. sp. at the type locality (Ryujin Island, Omura City). D–F, H. Adult female. F–G. Adult males. I. S. epicurus n. sp. , male. J. Same, female. The immature forms are uniquely pale green with only apex of the antennal segment II reddish brown ( Fig. 1E–G ), whereas the nymphs of most Japanese species have reddish brown basic coloration (e.g. Fig. 3B, G–H ), as documented by Yasunaga (2001b) , Yasunaga et al . (2013) and Yasunaga & Duwal (2021). FIGURE 3. Habittus images of live individuals for Sejanus spp. A . S. breviniger , adult males. B. Same, final instar nymph. C. S. komabanus , male. D. Same, female. E. S. vivaricolus , adults. F. Same, female reared with brine-shrimp eggs. G. Same, third instar nymph. H. Same, final instar nymph. I. S. neofunereus , male (Iriomote Is., Ryukyus, Japan). J. Same (Nantou, Taiwan). Description. Male: Macropterous. Body elongate oval, subparallel-sided, small-sized (2.0– 2.2 mm in total length), with relatively fragile integument; dorsal surface shiny fuscous, polished, with uniformly distributed, pale brown, simple, semierect setae. Head somewhat oblique; eye small; vertex weakly carinate basally. Antenna creamy yellow, relatively short; segment I about as thick as II; apical 1/4 of segment II dark reddish brown; apical parts of segments III and IV slightly darker. Labium shiny creamy yellow, reaching apex of metacoxa; apical part of segment IV reddish brown. Pronotum polished, minutely punctate; mesoscutum elevated anteriorly; scutellum flat; pleura dark brown, with sparsely distributed, simple, reclining setae ( Fig. 5B ); metathoracic scent efferent system grayish brown, with narrow orifice and small, semi-circular peritreme ( Fig. 5C ). Hemelytron polished, fuscous; basal margin of cuneus with white crescent fascia that is usually not interrupted; membrane including veins dark smoky brown. Coxae and legs creamy yellow; base and apex of each tibia suffused with orange ( Fig. 2I–J ): apex of each tarsomere III reddish; meta-tarsomere II longer than III ( Fig. 5F ); pretarsal structure as in Fig. 5G ; parempodia setiform, short; pulvilli rather widened. Abdomen shiny dark brown, sometimes whitish anteriorly. Male genitalia ( Figs. 4A–B ; 6A–F ): Phallotheca slender, tapered and weakly curved ( Fig. 6A, D ); left paramere with short, narrow hypophysis ( Fig. 6B ); right paramere with small, blunt-tipped hypophysis ( Fig. 6C ); endosoma (vesica) C-shaped ( Fig. 6E ), with short, minutely spinulate apex ( Fig. 6F ). FIGURE 4. Male (A–B, E, H, J–K) and female (C–D, F–G, I, L–M) genitalia of Sejanus epicurus n. sp. (A–D), S. ryujin n. sp. (E–G), S. brevis (H–I), S. komabanus (J) and S. vivaricolus (K–M). A. Pygophore with parameres. B, E, H, J–K. Vesica (endosoma). C, F, I, L. Sclerotized ring and adjacent structure. D, G, M. Ovipositor (gonapophysis I). Scale bars 0.1 mm. Female : Not sexually dimorphic, but body slightly wider and ovoid ( Figs. 1H ). Antennal segment II somewhat shorter. Female genitalia (4C–D; 7A–D): Generally simple in form; sclerotized ring thin-rimmed, rather oval ( Figs. 4C , 7A ); interramal sclerite with rather sparsely distributed comb-like microstructures ( Fig. 7C ). Measurements : See Table 1 . TABLE 1. Measurements for two new Sejanus species and their close relatives. Abbreviations—F: female, FM: femur, HT: holotype, L: length, LBM: labium, M: male; PRN: pronotum, PT: paratype, TB: tibia, VTX: vertex (interocular space), W: width.

Sejanus	Body	Head	VTX	PRN	HEM	Antennomere L			LBM	Metaleg L
L	W	W	W	W	II	III	IV	L	FM	TB
epicurus sp. n. M (N=4)	MAX MIN MEAN	2.08 2.01 2.04	0.54 0.51 0.52	0.26 0.22 0.24	0.75 0.66 0.70	0.89 0.80 0.85	0.72 0.62 0.68	0.39 0.30 0.35	0.26 0.20 0.23	0.90 0.83 0.87	0.75 0.66 0.71	1.16 1.05 1.10
F (N=3)	MAX MIN MEAN	2.21 2.01 2.11	0.56 0.48 0.52	0.29 0.26 0.27	0.78 0.72 0.76	1.08 0.90 0.99	0.63 0.59 0.61	0.36 0.32 0.34	0.24 0.21 0.23	0.90 0.87 0.89	0.74 0.65 0.70	1.13 1.02 1.07
ryujin sp. n. M (N=3)	MAX MIN MEAN	2.50 2.23 2.34	0.69 0.63 0.66	0.26 0.23 0.24	0.87 0.78 0.83	1.08 0.95 1.01	0.84 0.74 0.78	0.38 0.36 0.37	0.26 0.24 0.25	0.96 0.92 0.94	0.90 0.80 0.84	1.35 1.25 1.29
F (N=4)	MAX MIN MEAN	2.28 2.03 2.16	0.63 0.60 0.62	0.30 0.27 0.29	0.89 0.80 0.84	1.14 1.07 1.08	0.71 0.62 0.65	0.39 0.29 0.36	0.27 0.23 0.25	0.96 0.93 0.95	0.86 0.78 0.81	1.19 1.16 1.17
breviniger M (N=3)	MAX MIN MEAN	2.52 2.45 2.48	0.66 0.65 0.65	0.29 0.29 0.29	0.87 0.86 0.86	1.04 0.92 0.98	0.90 0.86 0.88	0.41 0.39 0.40	0.30 0.26 0.28	0.93 0.90 0.91	0.90 0.89 0.89	1.35 1.29 1.33
F (N=3)	MAX MIN MEAN	2.52 2.47 2.50	0.66 0.66 0.66	0.33 0.32 0.32	0.98 0.92 0.94	1.19 1.16 1.17	0.75 0.72 0.74	0.41 0.33 0.37	0.26 0.24 0.25	1.02 0.92 0.98	0.95 0.89 0.91	1.35 1.23 1.28
vivaricolus M (N=9)	MAX MIN MEAN	2.67 2.11 2.46	0.71 0.63 0.68	0.29 0.26 0.27	0.92 0.78 0.88	1.07 0.90 0.99	0.90 0.74 0.82	0.36 0.32 0.34	0.29 0.23 0.25	1.02 0.90 0.94	0.93 0.86 0.90	1.40 1.20 1.32
F (N=8)	MAX MIN MEAN	2.65 2.21 2.44	0.71 0.65 0.68	0.33 0.27 0.31	1.04 0.87 0.96	1.20 0.99 1.15	0.82 0.74 0.77	0.36 0.30 0.33	0.27 0.21 0.25	1.02 0.90 0.94	0.98 0.89 0.92	1.38 1.28 1.33

Etymology. Named for an ancient Greek philosopher Epicurus, (or Epikouros, 341–270 BC); one of his philosophies suggested ‘live secretly’, which is somewhat reminiscent of the cryptic lifestyle of this new species. Biology. Both adults and every stage of immature forms of this unique new species were observed to inhabit abaxial leaves ( Fig. 1C ) and insides of bracts ( Fig. 1A, E ) of Hibiscus taiwanensis . On the same plant, an undetermined thrips, and predaceous Termatophylum orientale Poppius, 1915 (Deraeocorinae: Termatophylini) ( Fig. 1K ) and Bilia sp. ( Anthocoridae : Oriini ) were found to coexist.