Georissus (Nipponogeorissus), Sato, 1972

Yasuda, Kohei & Yoshitomi, Hiroyuki, 2022, Revision of the genus Georissus (Coleoptera, Hydrophiloidea, Georissidae) of Japan, European Journal of Taxonomy 817 (1), pp. 111-142 : 121

Subgenus Nipponogeorissus Satô, 1972

Nipponogeorissus Satô, 1972: 212 . Type species: Georissus granulosus Satô, 1972 (by original designation).

Redescription

HEAD. Both clypeus and frons uneven, provided extensively with foveae, with distinct carinae; slr reaching anterior margin of frons; lsa connecting each other, forming U-shape. Granulation of clypeus indistinct. Mandibles ( Fig. 4K ) relatively large; lateral margin linear, apex unidentate; mola not developed. Antennae ( Fig. 4N ) relatively short; antennomere 4 as wide as antennomere 3, about twice as long as antennomere 3; pubescence of club short. Labrum ( Fig. 4E ) protruding anteriorly; spines on anterior margin indistinct. Apical labial palpomere ( Fig. 4H ) elongated oval, densely bearing short spines. Galea ( Fig. 4B ) densely bearing short setae.

PRONOTUM. Half oval; lateral portion slightly projecting laterally; disc densely provided with granules; smlg distinct; without sdn.

ELYTRA. Bearing four longitudinal costae consisting of granules. Humeral bulges distinct. Lateral ridges indistinct.

ABDOMEN. Ventrites densely bearing granules; ventrites 1–2 without vt and excavation.

MALE GENITALIA. Aedeagus elongated. Parameres as long as phallobase. Median lobe little shorter than parameres. Basal struts short. Phallobase bulbous at basal portion.

Remarks

This subgenus is distinguished by the combination of the following characters: pronotum provided with large granules extensively (not extensively in subgenera Georissus and Neogeorissus ); disc of clypeus and frons provided with many carinae, granulation indistinct (in other subgenera, granulation distinct). This subgenus comprises only two species from Japan and Papua New Guinea: the Japanese species is G. (Ni.) granulosus Satô, 1972 , and the other species is G. (Ni.) biroi Delève, 1969 . Georissus (Neogeorissus) maritimus Fikáček et al., 2012 described from Socotra Island ( Yemen) is similar to Nipponogeorissus species in the entirely granulated pronotum, and narrow, elongated aedeagus ( Fikáček et al. 2012).

Figures

Fig. 4. Mouth parts and antennae of Georissus spp. A–C. Left maxillae. D–F. Labrum. G–I. Labial palpi. J–L. Left mandibles. M–O. Left antennae. A, D, G, J, M. G. (G.) canalifer Sharp, 1888. B, E, H, K, N. G. (Ni.) granulosus Satô, 1972. C, F, I, L, O. G. (Ne.) japonicus Satô, 1972. Scale bars = 0.1 mm.