Ishiharanus iguchii ( Matsumura, 1916 )

Constant, Jérôme & Pham, Hong Thai, 2025, Issid planthoppers from Bach Ma and Phong Dien in Central Vietnam: (II) Tribe Hemisphaeriini (Hemiptera: Fulgoromorpha: Issidae), European Journal of Taxonomy 994 (1), pp. 1-76 : 47-51

Ishiharanus iguchii ( Matsumura, 1916)

Figs 1 , 2A , 4B , 26–28

Gergithus igushii [sic!] Matsumura, 1916: 98 (described).

Gergithus iguchii – Matsumura 1916: 86, 97, 116 (listed), 118 (key). — Esaki 1932: [1797], pl. 13 fig. 1 (described, illustrated); 1950: 322 (described), fig. 867 (illustrated). — Esaki et al. 1938: 65, pl. 29 fig. 113-2 (described, illustrated). — Fennah 1956: 506 (described, recorded from China, Che Kiang province, now Zhejiang), figs 17e–f (head and thorax), 19A (tegmen); 1978: 265 (recorded from Vietnam, Ninh Binh Province). — Metcalf 1958: 130 (catalogued). — Ishihara 1965: 131 (described), pl. 66 fig. 8 (dorsal habitus). — Chou et al. 1985: 124 (redescribed), fig. 116 (habitus, frons). — Che et al. 2007: 612 (transferred back from Ishiharanus to Gergithus ). — Zhang & Che 2009: 182 (listed). — Meng & Wang 2012: 5 (in key to species of Gergithus ). — Gnezdilov & Constant 2012: 573 (listed from Vietnam). — Chen et al. 2014: 52 (redescribed), fig. 2-16 (habitus, details, male terminalia). — Gnezdilov et al. 2014a: 93 (recorded from Hoa Binh Province, Vietnam). — Constant & Pham 2016: 2 (notes). — Hayashi & Fujinuma 2016: 352 (listed, distribution).

Ishiharanus iguchii – Hori 1969: 60 (transferred to Ishiharanus , records from Japan), fig. 2, 1–4 (dorsal head and thorax, frons, aedeagus, anal tube), pl. 3 fig. 6 (dorsal habitus). — Gnezdilov 2018: 1343 (transferred back to Ishiharanus from Gnezdilovius Meng, Webb & Wang, 2017 ), figs 18–23 (head and male terminalia). — Constant & Pham 2024a: 78 (in list of Issidae from Vietnam).

Gnezdilovius iguchii – Meng et al. 2017: 18, 22 (transferred to Gnezdilovius ), fig. 7g –h (head). — Zhang et al. 2020: 205 (in key in Chinese), 237 (described), 548 (in key in English), fig. 84 (head, wings, male and female terminalia), pl. 18a–c (habitus, frons).

Diagnosis

Ishiharanus iguchii ( Matsumura, 1916) can be recognized by:

(1) its colour pattern with frons chestnut brown and clypeus black, separated by distinct whitish line on suture and tegmina bright orange or red with large black markings, variable, from showing black markings merging together to completely black dorsally ( Figs 26 , 28A–B );

(2) the profemora colour divided into three broad bands, successively from base to apex, black, pale yellow and chestnut/dark brown ( Figs 26B, D, G , 28G );

(3) the anal tube in dorsal view about 1.31 times as long in midline as wide, suboval in shape with apical margin bisinuate (An – Fig. 27D );

(4) the lateroventral processes of the aedeagus symmetrical (lvp – Fig. 27N–O, S ), curved following curvature of aedeagus and more or less C-shaped and apically pointing laterad.

Differential diagnosis

The species is immediately separated from the other species of Ishiharanus by its unique colour pattern in the spotted form ( Fig. 26A, C ). The dark brown/black form ( Figs 26G , 28B ) is superficially similar to the black form of Melichergithus gravidus (Melichar, 1906) but can be separated by having a narrower, longer than wide, frons (1.18 times as long in midline as wide), while it is wider than long in midline (0.85 times as long in midline as wide) in M. gravidus ( Constant & Pham 2024a: fig. 14).

Material examined

JAPAN • 1 ♂; Honshu, Nara, forest above Nara Park ; [34°41′06″ N, 135°51′00″ E]; 200–250 m a.s.l.; 3 Oct. 1994; C. Lienhard leg.; MHNG .

VIETNAM • 1 ♂; Thừa Thiên-Huế Province, Bach Ma National Park, stairs going up to Hai Vong Dai ; 16°11′53.77″ N, 107°51′26.92″ E; 1272 m a.s.l.; May 2023; [by] net; Hoai leg.; VNMN • 1 ♂, 1 ♀; Thừa Thiên-Huế Province, Bach Ma National Park , summit; 16°11′18″ N, 107°50′56″ E; 1300–1400 m a.s.l.; 11–21 May 2023; J. Constant and L. Semeraro leg.; I.G.: 34.640; RBINS • 3 ♂♂; Ninh Binh Province, Cuc Phuong National Park ; 20°20′53″ N, 105°35′52″ E; 5–7 Apr. 2017; J. Constant and J. Bresseel leg.; I.G.: 33.447; RBINS • 1 ♂; Ninh Binh Province, Cuc Phuong National Park ; 20°19′00″ N, 105°36′30″ E; 19–23 Jul. 2011; J. Constant and J. Bresseel leg.; I.G.: 31.933; RBINS • 1 ♂; Ninh Binh Province, Cuc Phuong National Park ; 20°20′53″ N, 105°35′52″ E; 28 Apr. 2018; H.T. Pham leg.; VNMN • 2 ♀♀; Ninh Binh Province, Cuc Phuong [National Park] ; 20°20′55″ N, 105°35′52″ E; 413 m a.s.l.; 16 Sep. 2015; forest; A. Soulier-Perkins leg.; MNHN ( EH 24627 and 24637 ) • 1 ♂; Ninh Binh Province, Cuc Phuong National Park ; 20°19′21″ N, 105°37′36″ E; 200 m a.s.l.; 3–5 May 2014; L. Bartolozzi, G. Chelazzi, A. Bandinelli, S. Bambi and F. Fabiano leg.; n° Magazz. 2978; MZUF • 1 ♂; Ninh Binh Province, Cuc Phuong National Park, near Bong Center ; 20°21′05″ N, 105°35′30″ E; 385 m a.s.l.; 19–22 May 2019; L. Bartolozzi and S. Bambi leg.; n° Magazz. 3121; MZUF • 1 ♂; Hai Phong Province, Cat Ba National Park ; [20°47′50″ N, 107°24′25″ E]; 17 Jul. 2003; H.T. Pham leg.; VNMN • 2 ♀♀; Hoa Binh Province, [Ngoc Son-] Ngo Luong Nature Reserve ; 20°26′16″ N, 105°20′15″ E; 25–30 Jul. 2016; GTI Project; J. Constant and J. Bresseel leg.; I.G.: 33.282; RBINS • 1 ♂, 8 ♀♀; Thanh Hoa Province, Pu Hu Nature Reserve, near Yên ; 20°28′50″ N, 104°52′32″ E; 2–5 Jul. 2023; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.661; RBINS • 1 ♂; Ha Tinh Province, Vu Quang National Park, near Khe Chè station ; 18°22′38″ N, 105°18′41″ E; 13–15 Jul. 2023; V.T. Trung and N.T.T. Hoai leg.; VNMN • 1 ♂; same data as for preceding; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.661; RBINS • 2 ♂♂, 1 ♀; Hanoi Province, Ba Vi National Park ; 21°04′04″ N, 105°21′30″ E; 25–29 Jul. 2015; daytime collecting; J. Constant and J. Bresseel leg.; I.G.: 33.092; RBINS .

Redescription

MEASUREMENTS AND RATIOS. LT: ♂ (n = 1): 5.3 mm, ♀ (n = 1): 5.8 mm; LT/BB = 1.12; LTg/BTg = 1.38; LW/BW = 1.84; BV/LV = 1.72; LF/BF = 1.18.

HEAD ( Fig. 26A–E, G ). Vertex broader than long in midline, yellow-brown with posterior margin weakly carinate; anterior margin convex, posterior one concave and lateral subparallel; disc shallowly excavate with weak median carina. Side of head yellowish brown with vertical black band under eye, reaching level of frontoclypeal suture but not including base of antenna, remaining posteroventral portion pale yellowish, prolongating band on frontoclypeal suture. Frons elongate and smooth, chestnut brown (dark brown in dark form) and clypeus black, separated by distinct whitish line on suture; base of anteclypeus pale yellowish, apex black. Labium brown with last segment longer than broad, and shorter than penultimate one. Scape short, ring-shaped, brown; pedicel bulbous, dark brown.

THORAX ( Fig. 26A, C–E, G ). Pronotum very short, less than a quarter length of mesonotum in midline; anterior and posterior margins carinate; disc concave with an impressed point on each side of median line, with extremely narrow lateral fields behind eyes; chestnut brown, black behind eyes, all dark brown/ black in dark form. Mesonotum subtriangular, smooth, yellowish orange turning darker, brownish, in anterolateral angles, on scutellum and on transverse carina along anterior margin yellowish, all dark brown/black in dark form. Tegulae blackish brown.

TEGMINA ( Figs 26A, C, E, G , 28A–B ). Strongly convex; as long as broad when taken together in dorsal view; slightly concave at basicostal angle; smooth with dense reticulum of weakly raised veins and veinlets; mains veins barely distinct basally; bright orange or red with large black markings: on each tegmen, one basal, three aligned, more or less fused, at basal third, two aligned with lateral one larger, slightly beyond half-length, one apical; costal and postclaval margins bordered with black, all dark brown/black in dark form.

HIND WINGS ( Fig. 26F ). Yellow brown, turning to brown in distal half, unilobed, with veins darker than cells in brown area; elongate, about 1.85 times as long as wide, slightly shorter than tegmina. Venation reticulate with main longitudinal veins distinct basally (C, ScP+R, MP, CuA); numerous cross-veinlets. Anal area obsolete. Costal margin sinuate, cubital margin broadly rounded, distal margin rounded.

LEGS ( Fig. 26A–E, G ). Elongate and slender; pro- and mesofemora wider and shorter than corresponding tibiae, colour divided into three broad bands, successively from base to apex, black, pale yellow and chestnut brown, more contratsed on profemora; pro- and mesotibiae pale yellowish with basal ring and line along externoventral carina, black; metafemora variegated yellowish brown and black-brown; metatibiae yellowish brown with black spines. Metatibiae with 2 lateral spines on distal half and 6 apical spines. Metatibiotarsal formula: (2) 6/ 8–9 / 2.

ABDOMEN ( Fig. 26B ). Brown.

MALE TERMINALIA. Pygofer (Py – Fig. 27A–F ) 1.9 times as high as long in lateral view; in lateral view, dorsal margin horizontal followed posteriorly by rounded angle and oblique slope leading to abrupt, obtuse angle protruding posterad at upper ⅓; ventral ⅔ obliquely bisinuate; more or less circular in caudal view. Gonostyli (G – Fig. 27A–F ) robust in lateral view, with ventral margin broadly rounded in lateral view, posterior margin with middle portion projecting caudad, dorsal margin oblique basally, then upcurved to neck of capitulum; capitulum (ca) with elongate, twisted neck, directed dorsocephalad in lateral view, subrectangular with upper angle rounded and directed mesodorsad in caudal view, with small tooth at anterodorsal angle followed posterad by carina on external side curved cephalad at a right angle and ending in a tooth projecting cephalad in lateral view, in caudal view with deep, round emargination under carina. Anal tube (An – Fig. 27A–D, F ) rather short; in dorsal view about 1.31 times as long in midline as wide, suboval in shape with apical margin distinctly bisinuate, dorsoventrally flattened; in lateral view, anal tube weakly curved posteroventrad; apical margin straight in caudal view. Aedeagus curved posterodorsally and twisted, rather simple ( Fig. 27G–S ); lateroventral processes of aedeagus symmetrical (lvp), curved following curvature of aedeagus and more or less C-shaped and apically pointing laterad; ventral lobe of periandrium (vl) well developed, lanceolate and ending in rounded angle, shorter than aedeagus; dorsal lobe of periandrium (dl) shorter than aedeagus; aedeagus largely membranous with pair of elongate, pointed processes. Connective (co) well developed and curved, with tectiductus (te) well developed, with widely open foramen.

Biology

Ishiharanus iguchii was collected in April, May, July and October on lower vegetation and bushes ( Fig. 28A–B ), in moist evergreen tropical forest, at altitudes between 200 and 1400 m a.s.l.; in Bach Ma National Park it was only found at higher altitude between about 1300 and 1400 m a.s.l. at the “summit” area ( Figs 2A (5), 4B) collecting site.

Distribution

China: Fujian, Guangdong and Zhejiang; Japan: Honshu, Kyushu, Shikoku; Korean Peninsula; Vietnam ( Fig. 28C ): Hanoi capital*, provinces of Ha Tinh *, Hai Phong *, Hoa Binh, Ninh Binh, Thanh Hoa *, Thừa Thiên-Huế* (* = new province records).

Figures

Fig. 1. Map of the sampled localities in Thừa Thiên-Huế Province, Vietnam.

Fig. 2. Bach Ma National Park, habitats. A. Detailed map of the sampling areas (1 = ‘Yes Hue Eco’; 2 = ‘pheasant trail’; 3 = ‘low altitude’; 4 = ‘roadside’; 5 = ‘summit’; 6 = ‘near ranger station’. B. Typical habitat at ‘Yes Hue Eco’ sampling area, 17 May 2023.

Fig. 4. Bach Ma National Park, habitats. A. Typical habitat at ‘roadside’ sampling area, 21 May 2023. B. Typical habitat at ‘summit’ sampling area, 11 May 2023.

Fig. 26. Ishiharanus iguchii (Matsumura, 1916). A–F. Dissected ♂ (RBINS) from Bach Ma. A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Habitus, perpendicular view of frons. E. Habitus, anterolateral view. F. Right hind wing. G. Dissected ♂ from Cuc Phuong (RBINS), anterolateral view.

Fig. 27. Ishiharanus iguchii (Matsumura, 1916), ♂ (RBINS) from Cuc Phuong National Park, terminalia. A–F. Pygofer, anal tube and gonostyli.A. Lateral view.B. Posterolateral view.C. Caudal view.D. Dorsal view. E. Ventral view. F. Posterodorsal view. G–S. Aedeagus.G. Left lateral view. H. Right lateral view. I. Caudal view. J. Caudoventral view. K. Right laterodorsal view. L. Left posterolateral view. M. Left laterocaudal view. N. Left lateroventral view. O. Right lateroventral view. P. Right laterocaudal view. Q. Anterodorsal view. R. Dorsal view. S. Ventral view. Abbreviations: see Material and methods.

Fig. 28. Ishiharanus iguchii (Matsumura, 1916). A. Live specimen, spotted morph, Bach Ma National Park, roadside near summit, 21 May 2023. B. Live specimen, dark brown morph, Pu Hu Nature Reserve, 5 Jul. 2023. C. Distribution in Vietnam.