Georissus Latreille, 1809

Yasuda, Kohei & Yoshitomi, Hiroyuki, 2022, Revision of the genus Georissus (Coleoptera, Hydrophiloidea, Georissidae) of Japan, European Journal of Taxonomy 817 (1), pp. 111-142 : 113-115

publication ID	https://doi.org/ 10.5852/ejt.2022.817.1767
publication LSID	lsid:zoobank.org:pub:FFB05CE7-3712-4FD0-91B4-FD84863CF9D7
DOI	https://doi.org/10.5281/zenodo.6518773
persistent identifier	https://treatment.plazi.org/id/03BE8793-BE40-FFC9-FDB3-BD2E85300213
treatment provided by	Felipe
scientific name	Georissus Latreille, 1809
status

Treatment

Genus Georissus Latreille, 1809 View in CoL

Georissus Latreille, 1809: 377 View in CoL . Type species: Pimelia pygmaea Fabricius, 1798 (= Byrrhus crenulatus Rossi, 1794 ) [monotypy].

Cathammistes Illiger, 1807a: 297 View in CoL ; 1807b: 322 [suppressed, cf. ICZN 1998: 58]. Gender: masculine.

Georyssus View in CoL [unjustified emendation] – Stephens 1828: 105.

Supplementary description

BODY. Black to reddish brown, oval, strongly convex dorsally.

CLYPEUS. Uneven, with granules or carinae on its surface; articulated carinae arising at antero-lateral portion of clypeus and reaching anterior portion of frons (slr in Fig. 1A View Fig ); a pair of distinct bulges (smb in Fig. 1A View Fig ) on antero-median portion of frons (in Nipponogeorissus and Neogeorissus ); sides of frons smooth, lacking granules (lsa in Fig. 1A View Fig ). Eyes developed, not protuberant. Antennae ( Fig. 4M–O View Fig ) short, 9-segmented, with 3-segmented pubescent club (7-segmented with one-segmented club in Australian species: Fikáček 2019). Mandibles ( Fig. 4J–L View Fig ) large and well sclerotized, partly concealed beneath clypeus and labrum; antero-lateral margin forming obtuse angle; apex pointed; internal margin with microtrichia except apex. Maxillary palpi ( Fig. 4A–C View Fig ) 4-segmented; palpomere 4 longest and nearly same length as palpomeres 1–3 combined. Labrum ( Fig. 4D–F View Fig ) semicircular, widest at base; lateral margins fringed with spines. Mentum subtriangular, strongly narrowed anteriorly, with long setae on disc. Labial palpi ( Fig. 4G–I View Fig ) as long as mentum; apical palpomere oval to oblong oval, densely bearing spines in interior margin.

PRONOTUM. Half oval to trapezoidal, divided into anterior and posterior portions; anterior portion irregularly arranged with granules or short grooves and pits, with shallow median longitudinal groove (smlg in Fig. 1B View Fig ); posterior portion more convex than anterior portion, with large fovea on anteromedian portion (cd in Fig. 1B View Fig ); posterior sides of cd with a pair of distinct foveae (sdp in Fig. 1B View Fig ) (only in Neogeorissus ); sublateral potion of posterior portion with distinct bulge (slb in Fig. 1B View Fig ); behind of slb with deep groove (pg in Fig. 1B View Fig ); sides somewhat protruding laterally, having dentation (sdn in Fig. 1B View Fig ) in Neogeorissus .

LEGS. Protrochantins concealed. Procoxae large, plate-like, concealing prosternum. Femora somewhat flattened. Tibiae slender, especially protibiae rather flattened. Tarsal formula 5-5-5 (5-4- 4 in Australian species: Fikáček 2019).

ELYTRA. Provided with ten punctate rows. All or alternate intervals slightly to highly raised. Hind wings well developed or absent in some species.

VENTRITES. Ventrites 1 and 2 connate; ventrite 1 large, with distinct granules; posterior margin of ventrite 1 and anterior margin of ventrite 2 with a pair of ventral teeth (vt in Fig. 8A View Fig ).

MALE GENITALIA ( Fig. 9 View Fig ). Aedeagus trilobate type, almost symmetrical.

FEMALE GENITALIA. Gonocoxite ( Fig. 10 View Fig ) long, almost cross each other posteriorly. Gonostylus short, provided with two long setae at apex. Median sclerite unilobed, densely bearing long setae. Spermatheca ( Fig. 11E–H View Fig ) slightly sclerotized, elongated oval. Bursal sclerite ( Fig. 11A–D View Fig ) somewhat developed in subgenus Neogeorissus , slightly asymmetrical.

Key to the species of the genus Georissus from Japan

1. Posterior portion of pronotum with a shallow median longitudinal groove, lacking granules or cd and sdp. Elytra bearing seriate large punctures. Elytral interstices smooth. Aedeagus broad, median lobe short ( Fig. 9A–B View Fig ). Subgenus Georissus Latreille, 1809 View in CoL ............................................................ 2

– Posterior portion of pronotum provided with granules or foveae. Elytra bearing distinct granules. Elytral interstices raised. Aedeagus narrow, median lobe short or long ( Fig. 9C–H View Fig ) ...................... 3

2. Granules of clypeus distinct, large and dense ( Fig. 6B View Fig ). Posterior portion of pronotum lacking a longitudinal groove ( Fig. 7B View Fig ). Internal margins of parameres covered with long setae ( Fig. 9B View Fig ) ..... ...................................................................................................................... G. (G.) babai Satô, 1970 View in CoL

– Granules of clypeus indistinct, small and sparse ( Fig. 6A View Fig ). Posterior portion of pronotum having a shallow longitudinal groove ( Fig. 7A View Fig ). Internal margins of parameres covered with short setae ( Fig. 9A View Fig ) .............................................................................................. G. (G.) canalifer Sharp, 1888 View in CoL

3. Posterior portion of pronotum densely bearing granules, lacking cd and sdp. Pronotum lacking sdn ( Fig. 7C View Fig ). Aedeagus extremely narrow, phallobase posteriorly widening ( Fig. 9C View Fig ). Subgenus Nipponogeorissus Satô, 1972 View in CoL ........................................................... G. (Ni.) granulosus Satô, 1972 View in CoL

– Posterior portion of pronotum provided with granules, present cd and sdp. Pronotum having sdn ( Fig. 1B View Fig ). Aedeagus narrow, phallobase subparallel-sided ( Fig. 9D–H View Fig ). Subgenus Neogeorissus Satô, 1972 View in CoL ......................................................................................................................................... 4

4. Elytral interstices 2, 4, 6 highly raised ( Fig. 5G–H View Fig ) ............................... G. (Ne.) takahashii View in CoL sp. nov.

– All elytral interstices equally raised ( Fig. 5D–F, I View Fig ) .......................................................................... 5

5. Coloration of body black. Elytral granules indistinct ( Fig. 5E–F View Fig ) ..................................................... ....................................................................................................... G. (Ne.) kurosawai Nakane, 1963 View in CoL

– Coloration of body dark reddish brown. Elytral granules distinct ( Fig. 5D, I View Fig ) ................................ 6

6. Coloration of body black to dark brown. Granulation of pronotum distinct ( Fig. 7D View Fig ). Median lobe shorter than parameres ( Fig. 9D View Fig ) ........................................................ G. (Ne.) japonicus Satô, 1972 View in CoL

– Coloration of dark reddish brown. Granulation of pronotum indistinct ( Fig. 7I View Fig ). Median lobe longer than parameres ( Fig. 9H View Fig ) ................................................................................. G. (Ne.) satoi View in CoL sp. nov.