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 ( Nipponogeorissus ) granulosus Satô, 1972 [Japanese name: Sesuji-marudoromushi] Figs 2C , 3B, H , 4B, E, H–I, N , 5C , 6C , 7C , 8C , 9C ; Table 1 Georissus ( Nipponogeorissus ) granulosus Satô, 1972: 212 . Georissus ( Nipponogeorissus ) granulosus – Satô 1981: 4 ; 1985: 205 . — Hansen 1999: 49 . Diagnosis Table 1. Measurements of Georissus ( G .) spp. and G . ( Nipponogeorissus) granulosus Satô, 1972 .

G. ( G .) canalifer (N = 53)	G. ( G .) babai (N = 20)	G. ( Ni .) granulosus (N = 5)
TL (mm)	1.46–2.30 (1.91)	1.34–1.90 (1.91)	1.28–1.54 (1.38)
EL (mm)	0.86–1.62 (1.27)	0.82–1.26 (1.09)	0.86–1.02 (0.92)
EW (mm)	0.90–1.38 (1.17)	0.82–1.16 (1.05)	0.70–0.88 (0.79)
PL (mm)	0.52–0.78 (0.64)	0.52–0.66 (0.60)	0.40–0.52 (0.46)
PW (mm)	0.70–1.04 (0.85)	0.68–0.88 (0.79)	0.52–0.62 (0.58)
PW/PL	1.08–1.66 (1.33)	1.15–1.41 (1.32)	1.15–1.35 (1.26)
EL/EW	0.86–1.23 (1.08)	0.83–1.24 (1.03)	1.05–1.26 (1.16)
EL/PL	1.43–2.48 (1.98)	1.58–2.07 (1.82)	1.87–2.20 (2.00)
EW/PW	1.10–1.56 (1.38)	1.21–1.53 (1.33)	1.28–1.47 (1.37)
TL/EW	1.45–1.84 (1.64)	1.34–1.86 (1.60)	1.57–1.83 (1.74)

This species is easily distinguished from other Japanese species of Georissus by the granulated pronotum and shape of male aedeagus; shape elongated and narrow, phallobase widening. This species is distinguished from Georissus biroi described from Papua New Guinea by the carinae of frons; G . granulosus has transverse carinae, in contrast to their absence in G . biroi . Material examined Holotype JAPAN – Honshu : Mie Pref. • ♀ ; Tsu-shi , Furukawa ; 23 Aug. 1958 ; H. Ichihashi leg.; EUMJ ( Fig. 3B, L ). Other material JAPAN – Honshu : Mie Pref. • 5 ex. ; Ise-shi , Iso-cho , Miya-gawa ; 16 Jun. 2008 ; K. Akita leg.; EUMJ . Redescription COLORATION ( Fig. 2C ). Black, mat, legs dark reddish brown. HEAD ( Fig. 6C ). Clypeus uneven, provided with foveae and carinae throughout; slr , consisted of granules, connecting to smb at median portion; smb nonsequential, connecting each other, forming oblong oval; lsa connecting each other, forming U-shape. PRONOTUM ( Fig. 7C ). Relatively large, widest at the middle. Pronotal disc provided with granules densely. Anterior portion provided with indistinct granules extensively; anterior margin smooth, not crenelated; smlg distinct, with longitudinal row of pits. Posterior portion slightly convex than anterior potion, bearing granulation regularly; lateral margins protruding; slb developed; pg indistinct, short. ELYTRA. Entirely granulate. Elytral intervals 2, 4, 6 and 8 elevated, forming longitudinal carinae. Humeral bulge distinct, bearing granules. Lateral ridges indistinct. Hind wings developed. ABDOMEN ( Fig. 8C ). Lateral margin of ventrites uniformly narrowing posteriorly. Ventrite 1 with large granules extensively. Granulation of ventrites 2–5 large and relatively indistinct. MALE GENITALIA ( Fig. 9C ). Aedeagus 0.37 mm long. Parameres slightly shorter than phallobase, basal portions of parameres combined as wide as anterior portion of phallobase; lateral margins. Median lobe shorter than parameres, subparallel-sided, slightly angular at apex; basal struts short. Phallobase about 2.4 times as long as wide, widening posteriorly; posterior portion with large basal foramen. FEMALE GENITALIA. Not examined. Biological notes This species inhabits tidal flats that are submerged at high tide ( Akita 2008 ). The holotype was collected at light ( Satô 1981 ). Distribution Japan : Honshu ( Mie Pref. ) ( Fig. 13 ).