Revision of the genus Georissus (Coleoptera, Hydrophiloidea, Georissidae) of Japan Author Yasuda, Kohei C660A24E-D4D7-4985-951F-A4093FFBEE57 Entomological Laboratory, Faculty of Agriculture, Ehime University, Tarumi 3 - 5 - 7, Matsuyama, 790 - 8566 Japan. koheizari303@gmail.com Author Yoshitomi, Hiroyuki 744FA6FC-2D84-41B7-8A6C-C1611CC68EE1 Entomological Laboratory, Faculty of Agriculture, Ehime University, Tarumi 3 - 5 - 7, Matsuyama, 790 - 8566 Japan. hymushi@agr.ehime-u.ac.jp text European Journal of Taxonomy 2022 2022-05-03 817 1 111 142 http://dx.doi.org/10.5852/ejt.2022.817.1767 journal article 55730 10.5852/ejt.2022.817.1767 529dc516-47b9-424e-93ac-3787e407e100 2118-9773 6517928 FFB05CE7-3712-4FD0-91B4-FD84863CF9D7 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). 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. 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. 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. 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 ).