Stenocranus chenzhouensis Ding, 1981

Fujinuma, Satoshi & Hayashi, Masami, 2025, Taxonomic revision of Japanese Stenocranus (Hemiptera: Fulgoromorpha: Delphacidae), Zootaxa 5706 (3), pp. 301-336 : 328-329

Stenocranus chenzhouensis Ding, 1981

[Japanese name: Hososuji-naga-unka]

( Figs 2 , 8–10 , 13 , 16 )

Stenocranus chenzhouensis Ding, 1981: 76 [ Type locality: China ( Hunan)].

Material examined. [Honshu] 2♂ 3♀ ( MH), Inayama, Aomori, Aomori Pref., 31. VIII. 1997 , T. Ichita; 6♂ 2♀ ( SF), Kamitakamori, Tsukidate, Kurihara , Miyagi Pref., 24. VII. 2022 , S. Fujinuma; 5♂ 2♀ ( SF), same data except 29. X. 2022 , S. Fujinuma; 2♂ ( MH), Sugao-numa, Mitsukaido , Ibaraki Pref., 20. IX. 1996 , M. Hayashi et al.; 5♂ 5♀ ( MH), Yanagiyatsu-numa, Namegawa , Saitama Pref., 18. X. 1996 , M. Hayashi et al.; 4♂ 2♀ ( MH), Akigase, Saitama-Urawa , Saitama Pref., 20. VI. 1990 ( light trap) , M. Hayashi et al.; 12♂ 11♀ ( SF), Murakuni, Iwatsuki , Saitama Pref. 26. VI. 2016 , S. Fujinuma; 5♂ 4♀ ( SF), same data except 25. IX. 2016 , S. Fujinuma; 54♂ 60♀ ( MH), Sugadaira Moor ( 1,250 m), 25. IX. 1985 , M. Hayashi et al.; 98♂ 109♀ ( MH), same data except 3. IX. 1996 ; 2♀ ( SF), Ibi Riv., Kaizucho-Fukuoka, Kaizu , Gifu Pref., 20. II. 2011 , S. Fujinuma.

Redescription. General coloration stramineous, paler in summer form. Frons with dark stripes. Genae with dark stripes. Mid-dorsal parts of vertex, pronotum, and mesonotum narrowly whitish, fringed with orange and dark stripes (orange stripes usually feeble even in winter form). Forewings as in S. kisimotoi . Male pygofer pale to dark brown.

Vertex about 1.6× as long as wide. Frons about 2.9× as long as wide; median carina forked in apical 1/3. Antennal segment II about 3.1× as long as wide. Forewing venation and hind leg spinulation as in S. niisimai . Post-tibial spur with 23–26 fine teeth.

Body length (mean): ♂ 5.1–5.6 mm ( 5.4 mm); ♀ 6.1–6.5 mm ( 6.3 mm).

Male genitalia: Similar to S. kisimotoi except gonostyles much broader; phallotheca broad in lateral view; opening near caudal side; two apical processes: left process long, falcate, slightly angulated; right process long, downcurved at right angle; anal tube with ventral margin bluntly angulated near midlength. Female genitalia: Similar to S. sapporensis except gonapophyses IX with 16–20 teeth, symmetrically diverged mostly. Gonoplacs semicircular in ventral view, broad, wider in apical half.

Distribution. Japan (Honshu), China.

Remarks. This species is similar to S. fallax in coloration and structure but can be distinguished by the following features: face with dark lines from base to apex (paler in basal two-thirds in S. fallax ), antennal segment II about 3.1× as long as wide (shorter in S. fallax ), and phallotheca with two apical processes subequal in length (right process shorter in S. fallax ).

Biological notes. This species is found in lowland to mountainous marshes and feeds on Carex dispalata Boott ( Cyperaceae ). Adults are usually observed from June to November, and females lay eggs in the host plants in late autumn as in S. sapporensis ; thus, this species may overwinter as eggs.

Figures

FIGURE 2. Habitus and faces of Stenocranus (all males except H). B, D, F, H, I, winter form; A, C, E, G, J, summer form.—A, S. tateyamanus; B, C, K, S. kisimotoi sp. nov.; D, E, L, S. takasagonis; F–H, M, S. fallax; I, J, N, S. chenzhouensis. Scales: 1.0 mm.

FIGURE 8. Female genitalia of Stenocranus, Ceratocranus gen. nov. and Terauchiana. A–H, gonapophysis IX in dorsal view; I–P, same in lateral view.—A, I, S. niisimai; B, J, S. tamagawanus; C, K, S. sapporensis; D, L, S. tateyamanus; E, M, S. kisimotoi sp. nov.; F, N, S. chenzhouensis; G, O, C. aurantius sp. nov.; H, P, T. singularis.

FIGURE 9. Male genitalia of Stenocranus and Ceratocranus gen. nov. in lateral view.—A, S. niisimai; B, S. tamagawanus; C, S. sapporensis; D, S. harimensis; E, S. tateyamanus; F, S. kisimotoi sp. nov.; G, S. takasagonis; H, S. fallax; I, S. chenzhouensis; J, S. tonghuaensis; K, C. agamopsyche; L, C. aurantius sp. nov. Scales: 0.2 mm.

FIGURE 10. Male genitalia of Stenocranus and Ceratocranus gen. nov. in ventrocaudal view.—A, S. niisimai; B, S. tamagawanus; C, S. sapporensis; D, S. harimensis; E, S. tateyamanus; F, S. kisimotoi sp. nov.; G, S. takasagonis; H, S. fallax; I, S. chenzhouensis; J, S. tonghuaensis; K, C. agamopsyche; L, C. aurantius sp. nov. Scales: 0.2 mm.

FIGURE 13. Male genitalia (A–I) and female genitalia (J–L) of Stenocranus. A–C, phallotheca in lateral view; D–F, same in ventral view; G–I, gonostyle in widest view; J–L, gonoplac in ventral view.—A, D, G, J, S. takasagonis; B, E, H, K, S. fallax; C, F, I, L, S. chenzhouensis.

FIGURE 16. Oviposition holes and eggs of stenocranine genera on plants. A, D, oviposition holes covered with wax; B, E, G, the holes removed wax; C, F, H, K, N, P, eggs in the holes.—A–C, S. fallax on Carex dispalata; D–F, S. chenzhouensis on C. dispalata; G, H, S. tonghuaensis on C. dispalata; I–K, C. agamopsyche on Phragmites australis; L–N, T. singularis on P. australis; O, P, P. yasumatsui (Ishihara) on Carex sp.