Isometopus amurensis Kerzhner, 1988

Figs 1 A – J, 2 A – H, 3 A – F, 6 A – G

Isometopus amurensis Kerzhner, 1988 a: 789. Lectotype (as holotype, see Kerzhner 1988 b: 4): ♂, Russia: Vityaz’, 15 km south of Sukhanovka; ZISP .

Isometopus jejuensis Kim & Jung, 2016: 138. Holotype: ♀, Korea: Jungmun-dong, Jeju Island; CNU . syn. nov.

Isometopus amurensis: Kerzhner 1988 b: 4 (redescription); Kerzhner and Josifov 1999: 3 (catalogue, distribution); Schuh 2002–2013 (web catalogue); Jung et al. 2015: 598 (distribution, Korea); Ahn et al. 2018: 381 (diagnosis, photo); KSAE and ESK 2021: 155 (list); Taszakowski et al. 2023: 185 (catalogue).

Isometopus jejuensis: KSAE and ESK 2021: 155 (list); Taszakowski et al. 2023: 186 (catalogue).

Type material examined.

Isometopus amurensis . Lectotype: ♂, “ [PRIMORSKY KRAI, Khasan \ District, Vityaz’ \ 15 km S of Sukhanovka \ Kerzhner 21. viii. 1982] ” [printed], back of the label: “ [shaking off branches of Quercus dentata] ” [handwritten] “ Holotypus Isometopus \ amurensis sp. n. \ Kerzhner det. 986 ” [printed + handwritten] “ Lectotypus \ Isometopus \ amurensis \ design. Kerzh. 1987 ” [printed + handwritten] also with ZISP catalogue number: INS _ HEM _ 0000123. Paralectotype: ♀, “ [PRIMORSKY KRAI, Khasan \ District, Vityaz’ \ 15 km S of Sukhanovka \ Kerzhner 20. viii. 1982] ” [printed], “ Paratypus Isometo- \ pus amurensis \ Kerzh. ” [printed + handwritten] “ Paralectotypus \ Isometopus \ amurensis \ design. Kerzh. 1987 ” [printed + handwritten], both deposited in ZISP, photographs examined. Isometopus jejuensis . Holotype: ♀, “ Jungmun-dong, Seogwipo-si, \ Jeju-do (Is.), Korea, 5. IX. 2015, \ on Neolitsea sericea, J. G. Kim ” [printed] “ Isometopus jejuensis \ Kim et Jung, 2016 ” [printed] “ HOLOTYPE ” [printed], deposited in CNU.

Additional material examined.

South Korea – Gyeonggi-do. • 1 ♂; 12, Byeoryang-ro, Gwacheon-si; 37°25.26'N, 126°59.42'E; on light; 15. viii. 2019; W. Kim leg. (SNU) • 1 ♀; Seoul National University Gwanak Arboretum, Anyang-si; 05. viii. 2015; M. Oh leg. (SNU) • 1 ♂, 2 nymphs (5 th); Jungang-dong, Gwacheon-si; 37°25.52'N, 126°59.27'E; 17. vi. 2023; W. Kim leg. (UMMZ) ; • 4 ♂♂, 4 ♀♀, 2 nymphs (5 th); same locality; 21. vi. 2023; W. Kim leg. (SNU) • 1 nymph; Manan-gu, Anyang-si; 37°25.96'N, 126°54.92'E; 21. vi. 2024; W. Kim leg. (UMMZ) • 2 nymphs; Ilsan lake park, Goyang-si; 37°39.17'N, 126°45.85'E; 20. vi. 2024; W. Kim leg. (SCNU) • 5 nymphs (four 5 th); Gwanggyo Park, Jangan-gu, Suwon-si; 37°18.02'N, 127°01.80'E; 22. vi. 2024; W. Kim and M. Choi leg. (SCNU) • 1 ♂, 2 ♀♀, 4 nymphs (two 5 th); same locality; 26. vi. 2024; W. Kim and M. Oh leg. (SNU) • 5 ♂♂, 4 ♀♀, 1 nymph; Jungang-dong, Gwacheon-si; 37°25.52'N, 126°59.27'E; 26. vi. 2024; W. Kim leg. (SNU, SCNU) • 1 ♂, 2 ♀♀, 2 nymph (one 5 th); same locality and collector; 28. vi. 2024 (UMMZ) . – Incheon. • 1 ♂, 2 nymphs; Sorae Wetlands Ecology Park, Nonhyeon-dong, Namdong-gu; 37°24.55'N, 126°44.72'E; 14. vi. 2023; W. Kim leg. (SCNU) . – Jeollanam-do. • 1 ♀, 2 nymphs (5 th); Yongdang-dong, Suncheon-si; 34°58.30'N, 127°29.29'E; 7. vii. 2024; W. Kim leg. (SCNU) . – Jeju-do. • 2 nymphs; Hoecheon-dong, Jeju-si; 33°26.96'N, 126°38.36'E; 5. vii. 2025; W. Kim leg. (UMMZ) .

Diagnosis.

Sexually dimorphic (Figs 1, 2, 6). Easily distinguished from congeners in East Asia by the light brown frons and distinct punctation pattern (Fig. 2 E – H); hyaline hemelytra, and apically white scutellum in males; yellowish-white hemelytra with a dark band on the posterior half of corium in females; nymphs as in Fig. 6 E – G. As suggested by Kerzhner (1988 b), this species is externally similar to I. tianjinus Hsiao, 1964, but I. amurensis can be distinguished by the tip of the left paramere not swollen in male, and the black scutellum except for the white apical 1 / 3–1 / 4 in females (Hsiao 1964; Kerzhner 1988 b; Liu et al. 2022). However, since the known descriptions and figures for I. tianjinus are brief, future works are needed to clearly elucidate the diagnostic characters between I. tianjinus and I. amurensis .

Distribution.

Russia (Far East: Amur Oblast, Primorsky Krai) (Kerzhner 1988 b), South Korea (Gyeonggi-do, Gangwon-do, Jeollabuk-do, Jeollanam-do, Jeju-do) (Jung et al. 2015; Kim and Jung 2016; Ahn et al. 2018).