Stenocranus niisimai Matsumura, 1935

Fujinuma, Satoshi & Hayashi, Masami, 2025, Taxonomic revision of Japanese Stenocranus (Hemiptera: Fulgoromorpha: Delphacidae), Zootaxa 5706 (3), pp. 301-336 : 306-310

Stenocranus niisimai Matsumura, 1935

[Japanese name: Ezo-naga-unka (Niijima-naga-unka)]

( Figs 1 , 3 , 4 , 6–11 , 15 )

Stenocranus niisimai Matsumura, 1935: 130 [ Type locality: Japan ( Hokkaido: Teshio )].

Stenocranus nijimai (!): Ishihara, 1949: 29 (misspelling).

Stenocranus breviceps Matsumura, 1935: 127 (nec Dozier, 1922) [ Type locality: Japan ( Hokkaido)].

Stenocranus matsumurai Metcalf, 1943: 172 (replacement name for S. breviceps Matsumura, 1935 ). syn. nov. Stenocranus hongtiaus Kuoh, 1980: 413 [ Type locality: China ( Gansu)].

Stenocranus macromaculatus Ding, 2006: 107 [ Type locality: China ( Jiling )]. syn. nov.

Lectotype designation. In the syntypes of Stenocranus breviceps Matsumura , one male and two females are preserved with a red type label on the same pin. The features of the females are identical to those of the original description of S. breviceps , but the male is conspecific with S. fallax Matsumura. Therefore , one female is designated as the lectotype.

Type material examined. Holotype ♀ ( SEHU), “ Japan [Niijima Teshio (in Japanese)] DR. MATSUMURA. // Niijimae sp. nov. det. Dr. Matsumura // (red label) Type Matsumura” . Lectotype ♀ of S. breviceps (here designated; SEHU), “Sapporo DR. MATSUMURA. // St. breviceps M. det. Dr. Matsumura // N // (red label) Type Matsumura” . Paralectotypes of S. breviceps : 1♀ ( SEHU), same data as lectotype ; 1♂ 1♀ ( SEHU), “Sapporo Matsum, (underside) 26/V // Stenocranus breviceps Matsum. ” .

Other material examined. [ Hokkaido] 1♀ ( MH), Misumai, Sapporo, 4. VIII. 1983, M. Hayashi; 5♂ 5♀ ( MH), Mt. Kenashi-yama, Otaru , 3. VIII. 2023 , M. Hayashi; 1♀ ( MH), Yanagizaki, Esashi , 6. X. 2010 , M. Hayashi et al.; [ Honshu ] 1♂ 4♀ ( MH), Kurohama, Hasuda , Saitama Pref., 22. IV. 1999 , S. Ishida; 3♂ 4♀ ( MH), same data except 6. VIII. 1999 ; 1♂ 2♀ ( MH), Heirinji, Iwatsuki , Saitama Pref., 16. VII. 1999 ( light trap) , S. Ishida; 2♂ 5♀ ( MH), Murakuni, Iwatsuki , Saitama Pref., 15. VII. 1999 ( light trap) , S. Ishida; 4♂ 8♀ ( MH), Higashiwada, Sakado , Saitama Pref., 12. V. 1999 , T. Nakata; 59♂ 55♀ ( MH), same data except 18. X. 1999 ; 35♂ 47♀ ( MH), Niihori, Hidaka , Saitama Pref., 30. VI. 1999 , T. Nakata; 21♂ 18♀ ( MH), same data except 2. XI. 1999 , T. Nakata; 7♂ 3♀ ( MH), Nagatoro, Saitama Pref., 8. VIII. 2006 ( light trap) , M. Hayashi et al.; 75♂ 28♀ ( MH), same data except 19. VI. 2007 ( light trap) ; 31♂ 13♀ ( MH), same data except 7. VIII. 2007 ( light trap) ; 18♂ 12♀ ( MH), same data except 4. IX. 2007 ; 8♂ 2♀ ( MH), same data except 6. XI. 2007 ; 3♂ 3♀ ( MH), Makuyama Park, Yugawara , Kanagawa Pref., 18. VII. 2015 ( light trap) , M. Hayashi et al.; 3♂ 3♀ ( MH), same data except 9. VII. 2016 ; 18♂ 14♀ ( MH), Kakuma Valley, Sanada , Nagano Pref., 5. IX. 1996 , M. Hayashi et al.; 2♂ 2♀ ( MH), Uchikubo, Miyama , Kyoto Pref., 13. XI. 1995 , M. Sueyoshi; 2♂ ( MH), Hamasaka, Mikata , Hyogo Pref., 15. VII. 1995 , M. Sueyoshi; 2♀ ( MH), Yuge, Kumenan , Okayama Pref., 15. VII. 1989 , M. Hayashi; 1♂ ( MH), Sugezawa, Nichinan , Tottori Pref., 7. V. 2003 , M. Sueyoshi; [ Kyushu ] 2♂ 2♀ ( MH), Ideno, Mitsuse , Saga Pref., 9. XI. 1995 , M. Hayashi et al.; 3♂ 3♀ ( SF), Mt. Shaka-dake, Hita , Oita Pref., 22. VI. 2019 , T. Nozaki; 1♀ ( MH), Yanase, Kokonoe , Oita Pref., 6. VII. 1996 , M. Hayashi et al.; 1♂ ( MH), Oriuzako, Miyazaki, Miyazaki Pref., 25. XI. 1996 , M. Hayashi et al.; [ Tsushima Is. ] 1♂ ( MH), Tanohama, Kami-agata , 27. X. 2002 , M. Hayashi et al.; 1♀ ( MH), Kuwa, Izuhara , 29. X. 2002 , M. Hayashi et al.; [ Shimo-Koshiki Is. ] 1♀ ( SF), Aose, Satsumasendai, Kagoshima Pref., 11. VII. 2014 ( light trap) , T. Nozaki; [ Amami-Oshima Is. ] 1♂ ( RUMF), Mt. Yuwan , 16. X. 1988 , S. Azuma.

Redescription. General coloration stramineous, paler in summer form. Vertex with anterolateral compartments darker. Frons with dark stripes along submedian carinae. Genae with dark stripes. Mid-dorsal parts of vertex, pronotum, and mesonotum widely whitish, fringed with orange stripes. Mesonotum usually with short dark stripes along inner and outer margins of lateral carinae (stripes sometimes lacking in summer form). Forewings translucent, brownish; veins darker; dark markings on apices of apical veins; dark stripes on membrane (rarely with large dark stripes from base to apex of forewings). Legs with dark stripes. Male pygofer stramineous except anterior margin narrowly darker.

Vertex about 1.4× as long as wide. Frons about 2.8× as long as wide; median carina forked in apical 1/3. Antennal segment II about 2.6× as long as wide. Pronotum about 0.8× as long as vertex. Mesonotum about 2.4× as long as pronotum. Forewing venation: ScP, RA, and RP unbranched, MP 3-branched, CuA 4-branched. Hind leg spinulation: tibia 5 (2 + 3), basitarsus 7 (2 + 5), 2nd tarsomere 4. Post-tibial spur with 18–22 fine teeth on posterior margin.

Body length (mean): ♂ 5.2–5.6 mm ( 5.4 mm); ♀ 5.9–6.2 mm (6.0 mm).

Male genitalia: Pygofer triangular in lateral view, weakly produced caudad in dorsal half of caudal margin; oval in caudal view, angulated at lateral sides of opening for gonostyles; diaphragm broad, without armature. Suspensorium rectangular in anterior view, elongated dorsally, without concavity. Gonostyles short, broad in widest view, directed medially at apices; basal angles long, with small process just above corner. Phallotheca basally bifurcated along ventral slit in ventral view, narrow in lateral view; left part short, with apical opening; right part long, laterally flattened apically, with two processes: dorsal process long, slightly downcurved; ventral process long, hooked. Anal tube rectangular in lateral view, widened in apical 2/3, with needle-shaped process connected with suspensorium on ventrobasal part; ventral margin with one pair of short processes near basal 1/3. Female genitalia: Gonapophyses VIII slender in ventral view, nearly smooth on lateroapical parts. Gonapophyses IX very broad in dorsal view, with 18–25 blunt teeth in apical 2/3. Gonoplacs semicircular in ventral view, broad, slightly acute in apical half.

Distribution. Japan ( Hokkaido, Honshu, Shikoku, Kyushu, Tsushima Is., Shimo-Koshiki Is., Amami-Oshima Is.), Korea, Taiwan, China, Russian Far East.

Remarks. This species is very similar to S. fallax Matsumura , particularly in the short dark stripes along submedian carinae of the frons but can be distinguished by the following features: mesonotum usually with short linear dark stripes along inner margins of lateral carinae (lacking in S. fallax ), pygofer mostly pale (dark except caudal margin in S. fallax ), gonostyles short and broad (slender in S. fallax ). Examination of the original description and syntypes of Stenocranus breviceps Matsumura (i.e., S. matsumurai Metcalf ) shows that the facial coloration and short gonostyles of the male genitalia are identical to those of S. niisimai . Therefore, S. matsumurai Metcalf should be considered a junior synonym of S. niisimai . Ding (2006) synonymized Stenocranus hongtiaus Kuoh with S. matsumurai and described Stenocranus macromaculatus Ding as a related species of S. matsumurai . The features of the original description of S. macromaculatus (large dark stripes on forewings and the configuration of the male genitalia) are consistent with those of S. niisimai ; thus, S. macromaculatus should be considered a junior synonym of S. niisimai .

Biological notes. This species occurs in a wide range of habitats, from mountainous regions to coastal wetlands, and feeds on Phragmites australis (Cav.) and Phragmites japonica Steud. ( Poaceae ). Females lay eggs exclusively in Phalaris arundinacea L. ( Poaceae ) growing around P. australis in field observations and laboratory rearing. However, adults and nymphs distinctly prefer P. australis , suggesting that P. arundinacea may be used for oviposition. This species is very common throughout Japan Proper and is frequently attracted to light.

Figures

FIGURE 1. Habitus and faces of Stenocranus (all males except G). A, D, H, J, winter form; B, C, E, I, summer form.—A–C, K, S. niisimai; D, E, L, S. tamagawanus; F, G, M, S. sapporensis; H, I, N, S. harimensis; J, O, S. tateyamanus. Scales: 1.0 mm.

FIGURE 3. Habitus, faces, forewings, and hind legs of Stenocranus and Ceratocranus gen. nov. (all males). A, winter form; B, summer form.—A, B, E, S. tonghuaensis; C, F, L, C. agamopsyche; D, G, M, O, C. aurantius sp. nov.; H, S. niisimai; I, N, S. tamagawanus; J, S. kisimotoi sp. nov.; K, S. takasagonis. Scales: 1.0 mm (A–D, H–M), 0.5 mm (N, O).

FIGURE 4. Habitus and labels of type material of Stenocranus (all males except A, C, I, Q). N, under side of locality label is surrounded by dotted line.—A, B, S. niisimai (holotype); C, D, S. breviceps Matsumura (lectotype); E, F, S. tamagawanus (lectotype); G, H, S. vittatus Matsumura (lectotype); I, J, S. koreanus (holotype); K, L, S. sapporensis (lectotype); M, N, S. ozenumensis (paratype); O, P, S. harimensis (lectotype); Q, R, S. elongatus (holotype).

FIGURE 6. Male genitalia of Stenocranus. A–D, suspensorium in anterior view; E–H, phallotheca in ventral view; I–L, gonostyle in widest view.—A, E, I, S. niisimai; B, F, J, S. tamagawanus; C, G, K, S. sapporensis; D, H, L, S. takasagonis.

FIGURE 7. Female genitalia of Stenocranus and Ceratocranus gen. nov. A, B, gonapophysis IX covered with gonapophysis VIII in dorsal view; C–H, apical part of gonapophysis VIII in ventral view.—A, S. takasagonis; B, C. agamopsyche; C, S. niisimai; D, S. tamagawanus; E, S. sapporensis; F, S. kisimotoi sp. nov.; G, S. fallax; H, C. aurantius sp. nov.

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 11. 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. niisimai; B, E, H, K, S. tamagawanus; C, F, I, L, S. sapporensis.

FIGURE 15. Oviposition holes and eggs of Stenocranus on plants.A, D, G, L, N, oviposition holes covered with wax; B, E, H, O, the holes removed wax; C, F, I, K, M, P, eggs in the holes.—A–C, S. niisimai on Phalaris arundinacea; D–F, S. tamagawanus on P. arundinacea; G–I, S. sapporensis on Scirpus wichurae; J, K, S. harimensis on Carex dispalata; L, M, S. tateyamanus on Carex scabrifolia; N–P, S. takasagonis on Schoenoplectiella juncoides.