Heterotoma planicornis

Heterotoma planicornis (Pallas, 1772) Figs 1, 2, 3, 4, 5, 6 Cimex planicornis Pallas, 1772: 23. (original description). Cimex spissicornis Fabricius, 1777: 300 (original description). Synonymized by Costa (1843: 55). Acanthia crassicornis Fabricius, 1794: 70 (original description). Synonymized by Reuter (1888: 667). Cimex crassipennis Turton, 1802: 609 (new name for Cimex crassicornis). Synonymized by Reuter (1888: 667). Heterotoma acinaciformis Costa, 1839: 20 (original description). Synonymized by Wagner (1968: 185), tentatively. Heterotoma planicornis: Tamanini (1962: 136) (diagnosis, description); Schuh (1995: 121) (catalog); Kerzhner and Josifov (1999: 248) (catalog); Schuh (2002–2013) (online catalog); Kment and Bryja (2006: 11) (redescription, figures, neotype designation, distribution, biology); Kment and Bryja (2012: 117) (correction); Aukema (2018) (online catalog). Diagnosis. This species can be distinguished by the combination of the following characters: dorsum covered with brown, suberect setae and pale, reclining sericeous setae (Figs 1 A – E, 2 A, D); antennal segment blackish brown, segments I and II densely covered with fuscous, suberect setae; segment II thick and elongated, somewhat flattened (Figs 1 A – E, 2 A – F); segments III and IV short, thin, and linear, basally pale; hemelytra entirely dark brown; labium reaching mesocoxae; femora pale green, without dark or reddish tinge; tibiae yellowish green, subbasally tinged with green; tarsus yellowish green, widely darkened at segments I and III; pygophore with one elongated, pointed-end structure and short, bifurcate structure (Fig. 3 A – C); male endosoma with two elongated, apically spinulate sclerites and thick and smooth, pointed-end basal sclerite (Fig. 4 A – D); sensory lobe of left paramere with thick structure covered with stiff setae, hypophysis with minute, hook-like structure (Fig. 4 E – G); sensory lobe of right paramere moderately curved and laterally with two dentation, hypophysis stout, apically blunt (Fig. 4 H – J); female genitalia with thick sclerotized ring (Fig. 5 A – C); interramal lobe spinulate, bifurcate proximally (Fig. 5 D, E). For more diagnostic characters and figures, see Tamanini (1962, 1981) and Kment and Bryja (2006, 2012). Measurements. Male (n = 5) / Female (n = 2). Total body length 4.45–5.00 / 4.75–4.85; head width across eyes 0.79–0.84 / 0.83–0.85; vertex width 0.33–0.36 / 0.35–0.39; lengths of antennal segments I – IV 0.53–0.59, 1.66–1.79, 0.49–0.53, 0.42–0.47 / 0.54–0.55, 1.64–1.70, 0.49–0.50, 0.44; labial length 1.57–1.63 / 1.53–1.65; mesal pronotal length including collar 0.63–0.71 / 0.61–0.62; basal pronotal width 1.01–1.12 / 1.04–1.10; width across hemelytron 1.28–1.39 / 1.39–1.63; cuneal length 0.69–0.88 / 0.76–0.78; cuneal width 0.33–0.39 / 0.33–0.35; lengths of metafemur, tibia, and tarsus 1.49–1.66, 2.05–2.40, 0.47–0.55 / 1.56–1.65, 2.13–2.22, 0.53–0.54. Distribution. Europe: most of the territory. Asia: Türkiye, South Korea (introduced) (new record). North America: Canada, USA (Wheeler and Henry 1992; Kerzhner and Josifov 1999; Kment and Bryja 2006) (introduced). Biology. This species exhibits a wide host range, feeding on plants from 12 angiosperm families (Kment and Bryja 2006). Our observations revealed that the Korean population inhabits Spiraea japonica (Rosaceae) (Fig. 1 F). The habitat of H. planicornis discovered in this study was limited to narrow artificial landscapes in urbanized areas, excluding larger available natural habitats such as parks. Material examined. South Korea, Seoul: 5 ♂, 1 ♀, near Hannam station, Dokseodang-ro 6, Yongsan-gu, on Spiraea japonica 3. vi. 2024, Soojeong Cho (SNU); 1 ♀, ditto, 17. vi. 2023, Soojeong Cho (SNU); 1 ♂, ditto, 5. vi. 2024, Minsuk Oh (NIBR).