Georissus (Georissus) canalifer Sharp, 1888

[Japanese name: Marudoromushi]

Figs 2A, 4A, D, G, J, M, 5A, 6A, 7A, 8A, 9A, 10A, 12A; Table 1

Georyssus canalifer Sharp, 1888: 244 .

Georyssus canalifer – Miwa 1937: 163.

Georissus (Georissus) canalifer – Satô 1972: 209; 1981: 3; 1985: 205. — Hansen 1999: 50.

Diagnosis

This species resembles palearctic species G. crenulatus, and is distinguished from the latter by the presence of shallow longitudinal groove on posterior portion of pronotum (lacking in G. crenulatus).

Material examined

JAPAN – Hokkaido • 10 ex.; Atsuma-cho, Yufutsu; 12 Jun. 1995; S. Hori leg.; EUMJ • 9 ex.; Kamikawagun, Shintoku-cho, Tomuraushi; 7 Jul. 2006; M. Hanatsuka and Y. Hirano leg.; EUMJ • 12 ex.; Rumoishi, Togeshita; 4 Jun. 2004; H. Yoshitomi leg.; EUMJ • 10 ex.; Hamanaka-cho, Esashito; 1 Aug. 2004; K. Takahashi leg.; EUMJ • 2 ex.; Hamanaka-cho, Biwase; 18 Jun. 1995; I. Matoba leg.; EUMJ • 2 ex.; Kaminokuni-cho, Yunotani; 26 Jun. 1994; S. Hori leg.; EUMJ • 5 ex.; Kamikawa, Ishikari-gawa: 14 Jun. 1986; H. Matsumoto leg.; EUMJ • 2 ex.; Tokachi, Ashoro; 24–31 Jul. 1959; K. Morimoto leg.; EUMJ • 2 ex.; Sapporo-shi, Jozankei; 27 Jul. 2002; H. Yoshitomi leg.; EUMJ • 1 ex.; Akan-cho, Shunkushitakaragawa; 16 Jun. 1995; I. Matoba leg.; EUMJ • 1 ex.; Toyokoro-cho, Toyokita-kaigan; 23 Jul. 1993; S. Hori leg.; EUMJ • 1 ex.; Taiki-cho, Rekifune-kawa; 23 Jul. 1993; S. Hori leg.; EUMJ .

Redescription

COLORATION (Fig. 2A). Black, weakly shining.

HEAD (Fig. 6A). Clypeus uneven, provided with large granules on anterior portion; slr consisted of carinae and granules, granulation of anterior portion distinct, in contrast to posterior portion indistinct. Frons provided with scattered granules. Longitudinal groove distinct, wide, and surrounded by granules; lsa narrow, linear.

PRONOTUM (Fig. 7A). Relatively small, widest at posterior ⅓; anterior portion sparsely provided with short grooves and small foveae; anterior margin smooth; s mlg deep, with short longitudinal grooves; posterior portion with small granules and shallow longitudinal grooves; lateral margin except anterior portion regularly bearing granules; slb indistinct, densely covered with large granules; pg short, subobsolete.

ELYTRA (Fig. 5A). Humeral bulges distinct. All intervals slightly elevated and provided regularly with punctures. Lateral ridges indistinct, but with row of small granules. Hind wings well developed.

ABDOMEN (Fig. 8A). Lateral margin of ventrites gradually narrowing posteriorly, especially ventrites 1–2 strongly narrowing. Granules of ventrite 1 large, relatively dense; vt large. Granulation of ventrites 2–4 indistinct, 5 distinct and dense.

MALE GENITALIA (Fig. 9A). Aedeagus 0.40 mm long. Parameres slightly shorter than phallobase; basal portions combined as wide as anterior portion of phallobase; lateral margins slightly bulbous at anterior portion; internal margins asymmetrical; anterior portion with short setae densely. Median lobe shorter than parameres, gradually narrowing apically; basal struts short. Phallobase about 1.8 times as long as wide, widening posteriorly; posterior portion with large basal foramen.

FEMALE GENITALIA (Fig. 10A). Latero-tergites 8 forming acute angle; apex strongly incurved. Spines of gonostylus long.

Biological notes

This species is common in Hokkaido and inhabits wet sandy river beds in summer (Sharp 1888; Miwa 1937).

Distribution

Japan: Hokkaido (Fig. 13); Russia: Sakhalin, Kunashir (Ryndevich et al. 2021).