Georissus ( Neogeorissus ) kurosawai Nakane, 1963

Yasuda, Kohei & Yoshitomi, Hiroyuki, 2022, Revision of the genus Georissus (Coleoptera, Hydrophiloidea, Georissidae) of Japan, European Journal of Taxonomy 817 (1), pp. 111-142 : 126-130

Georissus ( Neogeorissus) kurosawai Nakane, 1963

[Japanese name: Shiwamune-marudoromushi]

Figs 1 , 2E , 3C, I , 5E–F , 6E–F , 7E–F , 8E–F , 9E , 10D , 11B, F , 12C ; Table 2

Georyssus kurosawai Nakane, 1963: 63 .

Georyssus kurosawai – Nakane 1966: 58.

Georissus ( Neogeorissus) kurosawai – Satô 1972: 211; 1981: 3; 1985: 206. — Hansen 1999: 47.

Georyssus laesicollis Germar, 1831 – Kurosawa 1950: 1107 [misidentification].

Diagnosis

This species is similar to the European species, G. laesicollis Germar, 1831 , and is distinguished by the oblong oval body shape(more rounded body shape in G. laesicollis ) and length of median lobe: G. kurosawai longer than paramere, in contrast to shorter than paramere in G. laesicollis (see Fikáček 2012).

Material examined

Holotype JAPAN – Honshu : Aichi Pref. • ♂; Owari , Nagoya , Higashiyama ; 13 Jun. 1948; S. Osawa leg.; SEHU ( Fig. 3C, H ).

Other material

JAPAN – Hokkaido • 4 ex.; Otohuke-cho, Shihoro-gawa ; 1–3 Aug. 2003; H. Yoshitomi leg.; EUMJ • 25 ex.; Okushiri Isl., Tsurikakegawa ; 2Aug.2005; S. Hori leg.; EUMJ • 1 ex.; Okushiri Is. , Tsurikakegawa, Yachi Riv. ; 6–9 Jun. 2003; S. Hori leg.; pitfall trap; EUMJ. – Honshu : Miyagi Pref. • 1 ex.; Yakuraionsen ; 21 Aug. 1998; M. Satô leg.; EUMJ. – Honshu : Tochigi Pref. • 2 ex.; Ootawara-shi, Sabigawa ; 25 Jul. 1994; H. Yoshitomi leg.; EUMJ. – Honshu : Chiba Pref. • 2 ex.; Futtsu-shi ; 19 May 1998; H. Hamaji leg.; EUMJ • 1 ex.; Kimitsu-shi, Takihara ; 29 Jul. 2002; H. Ono leg.; EUMJ. – Honshu : Tokyo Pref. • 1 ex.; Nakagawara ; 26 Aug. 1941; I. Fujiyama leg.; EUMJ. – Honshu : Yamanashi Pref. • 15 ex.; Tsukiyono, Doushi ; 16 Aug. 1986; Y. Hirano leg.; EUMJ. – Honshu : Nagano Pref. • 8 ex.; Ina-shi, Todai-gawa ; 28 Aug. 2009; T. Yoshida leg.; EUMJ. – Honshu : Gifu Pref. • 17 ex.; Tokuyamamura, near Shiratani; ca 450 m alt.; 7 Jul. 1988; M. Hasegawa leg.; EUMJ. – Honshu : Aichi Pref. • 3 ex.; Toyota, Yahagi-gawa ; 8 Aug. 2001; Y. Utsunomiya leg.; EUMJ. – Honshu : Mie Pref. • 4 ex.; Yokkaichi ; 27 Jul. 1984; A. Amagasu leg.; EUMJ • 1 ex.; Yokkaichi ; 20 Jun. 1985; H. Ichihashi leg.; EUMJ • 4 ex.; Suzuka-shi, Ifuna-cho, Onbe-gawa ; 3 Jul. 2004; N. Narukawa leg.; EUMJ • 19 ex.; Asake-gawa, Yokkaichi ; 11 Jun. 1988; A. Amagasu leg.; EUMJ. – Honshu : Wakayama Pref. • 1 ex.; Honguu-cho ; 29 Sep. 2007; K. Takahashi leg.; EUMJ. – Honshu : Kyoto Pref. • 1 ex.; Katsura-gawa, Yose ; 25 Apr. 1941; M. Kubota leg.; EUMJ. – Shikoku : Ehime Pref. • 1 ex.; Shuso-gun, Tanbaracho, Yanadani ; 15 Jul. 2003; Y. Kashitani leg.; EUMJ • 3 ex.; Toon-shi, Yamanouchi, Shigenobu-gawa ; 1 Nov. 2020; K. Yasuda leg.; EUMJ • 9 ex.; same collection data as for preceding; 3 Nov. 2020; EUMJ • 7 ex.; same collection data as for preceding; 9 Dec. 2020; EUMJ • 5 ex.; same collection data as for preceding; 20 Dec. 2020; EUMJ • 6 ex.; same collection data as for preceding; 31 Dec. 2020; EUMJ .

Redescription

COLORATION ( Fig. 2E ). Black, weakly shining, legs dark reddish brown. Body surface often covered with greyish substance.

HEAD ( Fig. 6E ). Clypeus relatively smooth, provided with a few large granules on median portion; slr consisted of carinae and indistinct granules, reaching to mid-length of frons, posteriorly connected to smb by an arc of sparsely arranged large granules and formed a pair of half-rounded foveae; smb V-shaped and not connected each other, with indistinct granules; lsa with a few small granules at lateral portion.

PRONOTUM ( Fig. 7E ). Relatively small, widest at the middle. Anterior portion provided with granules and pits densely; anterior margin crenellated; smlg shallow and narrow, with distinct longitudinal row of pits. Posterior portion somewhat convex than anterior portion; cd circular and relatively small, surrounded by many granules; sdp oblong oval to rectangle, larger than cd, with some granules; slb well developed, provided with distinct granules at posterior portion; pg short and narrow, not reaching median portion of sdp; sdn poorly developed, provided with a few teeth.

ELYTRA. Widest at middle, slightly wider than pronotum in basal margin; suture and intervals slightly elevate, regularly bearing indistinct granules; punctures distinct and regular. Humeral bulge distinct, bearing with granules. Lateral ridges on each elytron weakly developed. Hind wings fully developed.

ABDOMEN ( Fig. 8E ). Lateral margin of ventrites gradually narrowing posterior, especially ventrites 1 and 2 strongly narrowing. All ventrites bearing sparse scattered granules.

MALE GENITALIA ( Fig. 9E ). Aedeagus 0.43 mm long. Parameres shorter than phallobase, their basal portions combined as wide as anterior portion of phallobase; lateral margins slightly articulated: internal margins slightly widening. Median lobe longer than parameres, the sides almost paralleled, but slightly bulbous at base; slightly angular at apex; basal struts long. Phallobase about 2.2 times as long as wide, sides paralleled: posterior portion with large basal foramen.

FEMALE GENITALIA. Latero-tergites 8 ( Fig. 10D ) forming obtuse angle; apex slightly or not incurved. Setae of gonostylus short. Spermatheca ( Fig. 11F ) elongated oval, relatively bulbous at apical portion. Bursal sclerite ( Fig. 11B ) slightly asymmetrical, well sclerotized.

Biological notes

This is a common species collected in all seasons. It inhabits wet sandy river beds and is often observed under rocks ( Fig. 12B ). This species was also collected using pitfall traps or light traps ( Arai 2006; Iwata & Iwata 2012).

Distribution

Japan: Hokkaido, Honshu ( Miyagi, Fukushima, Tochigi, Saitama, Chiba, Tokyo, Yamanashi, Shizuoka ( Tabira 2005) Gifu, Aichi, Mie, Wakayama, Kyoto Prefs), Shikoku ( Ehime Pref.) ( Fig. 13 ).

Figures

Fig. 1. Georissus (Ne.) kurosawai Nakane, 1963, showing terminology. A. Head. B. Pronotum. Abbreviations: cd = central depression; lsa = lateral smooth area; pg = posterior grooves; sdn = subbasal dentation; sdp = subbasal depression; slb = sublateral bulge; slr = sublateral ridge; smb = submedian bulge; smlg = shallow median longitudinal groove.

Fig. 2. Dorsal view of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E. G. (Ne.) kurosawai Nakane, 1963. F. G. (Ne.) takahashii sp. nov., holotype, ♂ (EUMJ). G. G. (Ne.) satoi sp. nov., holotype (EUMJ). Scale bars = 0.5 mm.

Fig. 3. Holotypes of Georissus spp. A–F. Dorsal habitus. G–L. Labels. A, K. G. (G.) babai Satô, 1970, ♂ (EUMJ). B, L. G. (Ni.) granulosus Satô, 1972, ♀ (EUMJ). C, H. G. (Ne.) kurosawai Nakane, 1963, ♂ (SEHU). D, J. G. (Ne.) japonicus Satô, 1972, ♂ (EUMJ). E, G. G. (Ne.) sakaii Satô, 1972, ♂ (EUMJ). F, I. G. (Ne.) katsuoi Nakane, 1995 (SEHU). Scale bars = 0.5 mm.

Fig. 5. Dorsal habitus of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 6. Head of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 7. Pronotum of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (H). I. G. (Ne.) satoi sp. nov.

Fig. 8. Ventrites of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E–F. G. (Ne.) kurosawai Nakane, 1963 from Hokkaido (E) and Nagano (F). G–H. G. (Ne.) takahashii sp. nov. from Kochi (G) and Okinawa (F). I. G. (Ne.) satoi sp. nov. Abbreviation: vt = ventral teeth. Scale bars = 100 μm.

Fig. 9. Male aedeagus of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ni.) granulosus Satô, 1972. D. G. (Ne.) japonicus Satô, 1972. E. G. (Ne.) kurosawai Nakane, 1963. F–G. G. (Ne.) takahashii sp. nov. from Kochi (F) and Okinawa (G). H. G. (Ne.) satoi sp. nov. Scale bar = 0.1 mm.

Fig. 10. Female ovipositor of Georissus spp. A. G. (G.) canalifer Sharp, 1888. B. G. (G.) babai Satô, 1970. C. G. (Ne.) japonicus Satô, 1972. D. G. (Ne.) kurosawai Nakane, 1963. E. G. (Ne.) takahashii sp. nov. F. G. (Ne.) satoi sp. nov. Abbreviations: gsty = gonostylus; ltg8 = latero-tergite 8. Scale bar = 0.1 mm.

Fig. 11. Female genital organs of subgenus Neogeorissus spp. A–D. Bursal sclerite. E–H. Spermatheca. A, E. G. (Ne.) japonicus Satô, 1972. B, F. G. (Ne.) kurosawai Nakane, 1963. C, G. G. (Ne.) takahashii sp. nov. D, H. G. (Ne.) satoi sp. nov. Scale bar = 0.1 mm.

Fig. 12. Living individuals (A, C) and habitat (B, D) of Georissus spp. A–B. G. (G.) canalifer Sharp, 1888 in Hokkaido; C–D. G. (Ne.) kurosawai Nakane, 1963 in Ehime. Photographs by HY (A–B) and KY (C–D).

Fig. 13. Distribution map of Georissus spp. Russian localities for Georissus (G.) canalifer Sharp, 1888 and G. (Ne.) japonicus Satô, 1972 are omitted.