Stenocranus tamagawanus Matsumura, 1935

Fujinuma, Satoshi & Hayashi, Masami, 2025, Taxonomic revision of Japanese Stenocranus (Hemiptera: Fulgoromorpha: Delphacidae), Zootaxa 5706 (3), pp. 301-336 : 310-314

Stenocranus tamagawanus Matsumura, 1935

[Japanese name: Tamagawa-naga-unka (Sesuji-naga-unka)]

( Figs 1 , 3 , 4 , 6–11 , 15 )

Stenocranus tamagawanus Matsumura, 1935: 131 [ Type locality: Japan ( Honshu : Tamagawa)].

Stenocranus koreanus Matsumura, 1935: 129 [ Type locality: Korea ( Suigen )]. syn. nov.

Stenocranus vittatus Matsumura, 1935: 132 [ Type locality: Japan ( Hokkaido: Sapporo )].

Stenocranus hokkaidoensis Metcalf, 1943: 168 (replacement name for S. vittatus Matsumura, 1935 ). syn. nov.

Stenocranus minutus : Ishihara, 1949: 26 (nec Fabricius, 1787).

Stenocranus tateyamanus : Ishihara, 1949: 27 (nec Matsumura, 1935).

Lectotype designation. In the syntypes of Stenocranus tamagawanus Matsumura , one male and one female are preserved with a red label on the same pin; thus, the male is designated as the lectotype. In the syntypes of Stenocranus vittatus Matsumura , one male and one female (abdomen missing in the female) are preserved with a red label on the same pin; thus, the male is designated as the lectotype.

Type material examined. Lectotype ♂ (here designated; SEHU), “[ Tamagawa (= Tama River ) (in Japanese)] 7/25 // Stenocranus tamagawanus n. // (red label) St. tamagawanus Type ” . Paralectotypes: 1♀ ( SEHU), same data as lectotype . Lectotype ♂ of S. vittatus (here designated; SEHU), “4/20 Japan [Toyohira (Sapporo) (in Japanese)] Matsumura // Stenocranus vittatus n. det. Matsumura // (red label) Type Matsumura // 14a” . Paralectotypes: 1♀ ( SEHU), same data as lectotype ; 1♀ ( SEHU), “4/20 Japan [ Toyohira (in Japanese)] Matsumura // Stenocranus vittatus Mats. ” ; 1♂ ( SEHU), “[ Sapporo (in Japanese)] 4.20 // Stenocranus vittatus Matsum. ” . Holotype ♀ of S. koreanus (SEHU) , “[Locality Suigen (= Suwon) Date IV. 13 Collector Hasegawa 1921 (in Japanese)] // 377 // (red label) S. koreanus n.” .

Other material examined. [ Hokkaido] 1♂ 2♀ ( MH), Lake Shirarutoro, Shibecha, 30. IX. 1997, K. Ijima; 3♂ 2♀ ( MH), Kosei, Shibecha , 6. V. 1997 , K. Ijima; 1♀ ( SF), Shotoshibetsu, Rikubetsu, Ashoro , 28. VII. 2012 , S. Fujinuma; 1♂ 1♀ ( MH), Yanagizaki, Esashi , 6. X. 2010 , M. Hayashi et al.; [ Honshu ] 1♂ ( MH), Yoriki, Matsuo, Hachimantai , Iwate Pref., 17. VII. 2001 , M. Hayashi et al.; 3♂ 3♀ ( MH), Furukawa-Miyazawa, Osaki , Miyagi Pref., 16. VII. 2010 ( light trap) , M. Hayashi et al.; 3♂ 2♀ ( MH), Kurohama, Hasuda , Saitama Pref., 22. IV. 1999 , S. Ishida; 3♂ 2♀ ( MH), same data except 19. VII. 1999 ; 3♂ 10♀ ( MH), Heirinji, Iwatsuki, Saitama Pref., 8. VIII. 1999, 8. VIII. 1999 , S. Ishida; 16♂ 15♀ ( MH), Murakuni, Iwatsuki , Saitama Pref., 22. XI. 1999 , S. Ishida; 1♂ 2♀ ( MH), Higashiwada, Sakado , Saitama Pref., 8. VII. 1999 , T. Nakata; 3♂ 2♀ ( MH), Niihori, Hidaka , Saitama Pref., 8. VII. 1999 , T. Nakata; 2♀ ( MH), Akigase, Saitama-Urawa , Saitama Pref., 6. VII. 1989 , M. Hayashi et al.; 1♂ 1♀ ( MH), same data except 8. IV. 1995 ; 1♀ ( MH), Sue, Hatoyama, Saitama Pref., 27. VII. 2010 ( light trap) , S. Shibazaki; 1♂ ( MH), Nagatoro, Saitama Pref., 4. XI. 2007 , M. Hayashi et al.; 1♂ 2♀ ( SF), Tama Riv., Komaki, Ôme, Tokyo Met. , 13. IX. 2014 , S. Fujinuma; 7♂ 7♀ ( SF), Lake Biwa, Shinasahicho-Fukamizo, Takashima , Shiga Pref., 25. VII. 2008 , S. Fujinuma; 1♀ ( MH), Hamasaka, Mikata , Hyogo Pref., 15. VII. 1995 , M. Sueyoshi; 1♂ ( MH), Hamasaka-shinden, Tottori City, Tottori Pref., 18. IX. 2003 ( light trap) , M. Sueyoshi; [ Kyushu ] 2♂ 2♀ ( TUA), Mt. Hiko, Soeda , Fukuoka Pref., 29. IV. 2008 , T. Mita; 1♂ 1♀ ( MH), Hanamure, Kokonoe , Oita Pref., 26. XI. 1996 , M. Hayashi et al. 1♂ ( SF), Mt. Tômi-san, Ushibuka, Amakusa , Kumamoto Pref., 23. VII. 2015 ( light trap) , T. Nozaki; [ Tsushima Is. ] 6♀ ( MH), Tanohama, Kami-agata , 23. X. 2000 , M. Hayashi et al.; 1♀ ( MH), Yakematsu, Mitsushima , 12. VII. 1995 , M. Hayashi et al.; [ Iki Is. ] 2♂ ( SF), Katsumotocho-Higashifure , 25. III. 2021 , T. Nozaki; [ Hirado Is. ] 1♂ 2♀ ( SF), Nakatsura Riv. , 20. VIII. 2017 , T. Nozaki.

Redescription. General coloration stramineous, paler in summer form. Vertex with anterolateral compartments slightly darker. Frons with dark stripes feeble and brownish. Genae with dark stripes. Mid-dorsal parts of vertex, pronotum, and mesonotum widely whitish, fringed with orange stripes. Forewings translucent, brownish; veins paler; long dark stripes on apical 2/3 of forewings. Legs with dark stripes (sometimes lacking in summer form). Male pygofer usually stramineous.

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 0.7× as long as vertex. Mesonotum about 2.3× as long as pronotum. Forewing venation and hind leg spinulation as in S. niisimai . Post-tibial spur with 13–18 fine teeth.

Body length (mean): ♂ 5.1–5.8 mm ( 5.5 mm); ♀ 5.6–6.1 mm ( 5.8 mm).

Male genitalia: Pygofer triangular in lateral view, slightly 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 triangular in anterior view, short, narrowed dorsally, with shallow concavity. Gonostyles long in widest view, broad, directed medially at apices; basal angles long, with small protrusion on its corner. Phallotheca with narrow ventral slit in ventral view; broad in lateral view, laterally flattened and weakly produced ventrad in subapical part; apical process long, falcate, slightly recurved at apex. Anal tube rectangular in lateral view; ventral margin with two pairs of short processes near apical 1/3. Female genitalia: Gonapophyses VIII slender in ventral view, weakly serrated on lateroapical parts. Gonapophyses IX as in S. niisimai except with 24–30 teeth. Gonoplacs semicircular in ventral view, broad, wider in apical half.

Distribution. Japan ( Hokkaido, Honshu, Shikoku, Kyushu, Tsushima Is., Iki Is., Hirado Is.), Korea, Russian Far East.

Remarks. This species can be distinguished from other Japanese congeners by the forewings bearing long dark stripes from near from near base to apex (without other dark markings) and by the gonostyles with long basal angles. Examination of the syntypes of Stenocranus vittatus Matsumura (i.e., S. hokkaidoensis Metcalf ) from Japan and the holotype of Stenocranus koreanus Matsumura from Korea shows that these features (frons with brownish stripes, long dark stripes on forewings, and shape of gonostyles) are identical to those of S. tamagawanus . Although S. koreanus has page precedence over S. tamagawanus , the former was described based on a single female specimen, whereas the latter was based on both male and female specimens. Therefore, it is preferable that S. hokkaidoensis and S. koreanus become junior synonyms of S. tamagawanus for stability and universality of nomenclature (ICZN 4th edition: Recommendation 24A). The collection date given in the original description of S. koreanus ( July 30, 1921) appears to be incorrect, as the specimen label reads April 13, 1921 and the dark coloration of the holotype indicates a winter form. This species (as S. hokkaidoensis ) has been suspected by some authors (e.g., Mochida & Okada 1971, Anufriev & Emeljanov 1988) to be S. minutus (Fabricius) or its subspecies. In this study, no distinctive differences were found in the male genitalia. However, the female genitalia can be separated by the shape of the gonapophyses VIII, as illustrated by Asche & Hoch (1983) and Fujinuma (2022).

Biological notes. This species is commonly found in lowland and lower mountainous wetlands of the Japan Proper and feeds on Phalaris arundinacea L. ( Poaceae ). Females lay eggs in sheathes or leaves of the host plant near the ground and coat oviposition holes with powdery wax, as widely observed among Japanese Stenocranus species (except S. niisimai , which uses both powdery wax and cotton-like wax).

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.