Stenocranus sapporensis Matsumura, 1935

Fujinuma, Satoshi & Hayashi, Masami, 2025, Taxonomic revision of Japanese Stenocranus (Hemiptera: Fulgoromorpha: Delphacidae), Zootaxa 5706 (3), pp. 301-336 : 314-318

Stenocranus sapporensis Matsumura, 1935

[Japanese name: Sapporo-naga-unka (Oze-naga-unka)]

( Figs 1 , 4 , 6–11 , 15 )

Stenocranus sapporensis Matsumura, 1935: 131 [ Type locality: Japan ( Hokkaido: Jozankei and Sapporo )].

Stenocranus ozenumensis Ishihara, 1952: 35 [ Type locality: Japan ( Honshu : Oze)]. syn. nov.

Stenocranus minutus : Matsumura, 1900: 257 (nec Fabricius, 1787).

Lectotype designation. In the syntypes of Stenocranus sapporensis Matsumura , three males (all damaged, one male stored in glycerin) are preserved with a red label on the same pin; thus, one male is designated as the lectotype.

Type material examined. Lectotype ♂ (here designated; SEHU), “28/VIII Ziozan (= Jozankei) // Stenocranus sapporensis n. det. Matsumura // (red label) Type Matsumura // 13a”. Paralectotypes: 2♂ ( SEHU), same data as lectotype; 1♀ ( SEHU), “[Jozankei (in Japanese)] 8/28 // S. sapporensis M. // [Sapporo Hosozu Unka (in Japanese)]”; 1♂ ( SEHU), “16/IX Maruyama”. Holotype ♂ of S. ozenumensis (EUMJ) : “ ♂ // 21 IX-1950 OZE H.HASEGAWA, (underside) [Kamitashiro (in Japanese)] // (red label) HOLOTYPE Stenocranus ozenumensis Ishihara, 1952 ”. Paratype: 1♂ ( EUMJ): same data as holotype except “(yellow label) PARATYPE Stenocranus ozenumensis Ishihara, 1952 ”.

Other material examined. [ Hokkaido] 2♂ 1♀ ( SF), Kônomai, Mombetsu, 1. IX. 2016, S. Fujinuma; 5♂ 5♀ ( MH), Mizuho, Higashiasahikawa, Asahikawa , 3. IX. 2016 , M. Hayashi et al.; [ Honshu ] 2♂ 8♀ ( MH), Matsukawa H.S. ( 890 m), Hachimantai , Iwate Pref., 27. VIII. 2000 , M. Hayashi et al.; 4♂ ( MH), same data except 9. IX. 2001 ; 41♂ 25♀, Appi Highlands, Hachimantai , Iwate Pref., 26. VIII. 2000 , M. Hayashi et al.; 5♂ 17♀ ( MH), same data except 12. IX. 2001 ; 4♂ 3♀ ( MH), Gozaisho ( 890 m), Hachimantai , Iwate Pref., 27. VIII. 2000 , M. Hayashi et al.; 6♂ 5♀ ( MH), Fukenoyu ( 1,120 m), Kazuno , Akita Pref., 28. VIII. 2000 , M. Hayashi et al.; 1♂ 1♀ ( MH), Ôyachi ( 1,080 m), Kazuno , Akita Pref., 13. IX. 2000 , M. Hayashi et al.; 1♂ ( MH), Naganuma ( 1,100 m), Kazuno , Akita Pref., 10. IX. 2001 , M. Hayashi et al.; 1♂ ( MH), Ônuma ( 960 m), Kazuno , Akita Pref., 23. VIII. 2000 , M. Hayashi et al.; 5♂ 5♀ ( MH), Tachiyazawa, Shonai , Yamagata Pref., 18. IX. 2010 , M. Hayashi et al.; 3♂ 2♀ ( MH), Hakase Pass, Showa , Fukushima Pref., 21. VIII. 2010 , M. Hayashi et al.; 6♂ 7♀ ( SF), Yubiso, Minakami , Gunma Pref., 28. VIII. 2011 , S. Fujinuma; 4♂ 1♀ ( SF), Yunosawa, Mikuni, Yuzawa , Niigata Pref., 31. VII. 2016 , S. Fujinuma; 1♀ ( MH), Suga-ike ( 1,320 m), Sanada , Nagano Pref., 4. IX. 1996 , M. Hayashi et al.; 3♂ 2♀ ( SF), Norikura Highland, Azumi, Matsumoto , Nagano Pref., 14. IX. 2010 , S. Fujinuma; 3♂ 2♀ ( MH), Abô-daira ( 1,600 m), Hirayu , Gifu Pref., 3. IX. 1991 , M. Hayashi.

Redescription. General coloration brown. Frons and genae mostly darker, carinae paler. Mid-dorsal parts of vertex, pronotum, and mesonotum widely whitish, usually fringed with dark stripes. Forewings with dark markings on apices of apical veins; curved dark stripes on apical half of inner sides. Male pygofer pale to dark brown.

Vertex about 1.4× as long as wide. Frons about 2.6× as long as wide; two median carinae approximated. Antennal segment II about 2.8× as long as wide. Forewing venation and hind leg spinulation as in S. niisimai . Post-tibial spur with 12–16 fine teeth.

Body length (mean): ♂ 5.3–5.5 mm ( 5.4 mm); ♀ 6.0– 6.3 mm ( 6.2 mm).

Male genitalia: Pygofer triangular in lateral view, slightly produced caudad in dorsal half of caudal margin; oval in caudal view, relatively narrow, acutely angulated at lateral sides of opening for gonostyles; diaphragm broad, without armature. Suspensorium rectangular in anterior view, short, widened dorsally, with deep concavity. Gonostyles narrow in widest view, distinctly curved dorsad in apical part; basal angles very short. Phallotheca broad in lateral view; opening on left side; apical process long, falcate, with short process (rarely missing) at its base on right side. Anal tube elongate in lateral view; ventral margin bluntly angulated near midlength. Female genitalia: Gonapophyses VIII slender in ventral view, strongly serrated on lateroapical parts. Gonapophyses IX broad in dorsal view, with 16–19 acute teeth in apical 1/3; the teeth strongly diverged into asymmetrical two rows. Gonoplacs semicircular in ventral view, broad, slightly acute, narrow in basal half.

Distribution. Japan ( Hokkaido, Honshu, Shikoku).

Remarks. This species can be distinguished by the frons with two median carinae and the forewings with curved dark stripes on apical half. Matsumura (1935b) corrected his former record of Stenocranus minutus (Fabricius) from Hokkaido ( Matsumura 1900) to S. sapporensis . In contrast, Ishihara (1949) synonymized S. sapporensis with S. minutus and subsequently described Stenocranus ozenumensis Ishihara , having “a remarkable black arched marking” on the forewing as in S. sapporensis , from Honshu ( Ishihara 1952). Examination of the type material of S. sapporensis and S. ozenumensis indicates S. sapporensis is not identical to S. minutus but to S. ozenumensis based on the forewing coloration and male genital configurations. Thus, S. ozenumensis is regarded as a junior synonym of S. sapporensis .

Biological notes. This species usually inhabits mountainous marshes, particularly in cold climates, and feeds on Scirpus wichurae Boeck. and some Carex sedges ( Cyperaceae ). Females lay eggs in basal parts of leaves. Unlike other Japanese congeners, this species is probably univoltine, with females laying eggs by late autumn.

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 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.