Review of the Taiwanese Laccobius Erichson, 1837 (Coleoptera: Hydrophilidae) with description of a new species Author Liu, Hsing-Che Taiwanese Society of Insect Natural History, No. 8, Wufeng Rd., Hsinchu County 310, Taiwan. Author Fikáček, Martin 0000-0002-2078-6798 Department of Biological Sciences, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung City 80424, Taiwan. & Department of Entomology, National Museum, Cirkusová 1740, CZ- 19100 Praha 9 - Horní Počernice, Czech Republic. & Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ- 12844 Praha 2, Czech Republic. mfikacek @ gmail. com; https: // orcid. org / 0000 - 0002 - 2078 - 6798 mfikacek@gmail.com text Zootaxa 2021 2021-04-20 4963 3 587 599 journal article 7088 10.11646/zootaxa.4963.3.11 37bbbcdd-7455-4fd2-854c-49f010b3b27c 1175-5326 4704278 05C2E47F-426D-42EF-B07E-D586C63B6527 Laccobius ( Microlaccobius ) formosus Gentili, 1979 台灣flǿ牙ḃ ( Figs 11, 15 , 19 , 23 ) Laccobius ( Microlaccobius ) formosus Gentili, 1979: 48 . Material examined. TAIWAN : TAITUNG : 1 male , 3 females , ( NMNS ): Lanyu [ ae嶼 ], Yonghsing , 17-19.VIII.1998 . H.T.Shih & K.W.Huang. L.I.T, [specimens NMNS ENT 3209-1094 , 3209-1690 , 3209-1141 , 3209-1403 ] ; 1 male , ( NMNS ): Donghe [ 東河 ], Jindonglai Forest Road, 4.VIII.2012 , Y. T. Wang leg , Light . KAOHSIUNG : 1 male , 6 spec. , ( NMNS ): Liukuei , Shanping [ Oi平 ], 22-23.IV.2004 . C.S.Lin & W.T.Yang , UV light trap , [specimens NMNS ENT 4409-723 , 4409-737 , 4409-712 , 4409-919 , 4409-734 , 4409-709 , 4409-711 ] ; 1 male , ( HCLC ): Liouguei District [ 六 AE區 ], Laonong River [ Ž濃ë ], 22.996017°N 120.638178°E , 229m , 24.VI.2020 . Hsing-Che Liu & Uitsiann Ong leg. HSINCHU : 1 male , 1 female , ( HCLC ): Hengshan Township [ DZ山ė ], Youluo Stream [ 油ǎë ], 24.714584°N 121.141335°E , 172 m , 14.II.2019 . Hsing-Che Liu leg. NANTOU : 1 males , 5 spec. , ( NMNS ): Puli Township [ 埔¶ D ], Meixi [ 眉ë ], 23.988475°N 121.017601°E , 536m , 12.II.2020 . Hsing-Che Liu leg. ; 9 spec. , ( NMPC ) 4.4 km W of Puli Township start of the Shikeng Road , 530 m 23.988000 , 121.017833 15.II.2020 . Fikáček , Hu , Liang & Liu lgt. (2020-TW003) . PINGTUNG : 1 spec. , ( TARI ): Neipu [ 內埔 ], 26.II.2020 . Y.-T. Chung leg. ; 1 male , 2 spec. , ( HCLC ) Ligang Township [ ¶ffiė ], Erchong River [ 二AEë ], 22.7982°N 120.5011°E , 32m , 26.IV.2020 . Hsing- Che Liu leg. TAINAN : 1 male , ( HCLC ): Zuozhen District [ 左D區] , Jiaotan [ m潭 ], 23.V.2020 . by light trap , Kunta Ho & Wei-Chai Wang leg. TAICHUNG : 8 spec. ( NMPC ): Heping distr,, Bashianshan Mts. , Dajiaxi River at Songhe village , 24.17996°N 120.98233°E , 665 m , 5.i.2018 , stony river partly with gravel banks: in fine gravel below stones and in green algae mats at the side of the river, Fikáček, Liang & Hsiao lgt. (2018-TW01) ; 1 spec. ( NMPC ): Heping distr. , Xueshankengxi River E of Taoshan village , 24.32684°N 120.95377°E , 743 m , 6.i.2018 , in gravel and among algae at side of a large stony river, Fikáček , Liang , Hsiao lgt. (2018-TW06) . FIGURES 1–5. Laccobius ( Microlaccobius ) hoi sp. nov. , male. 1–2: habitus of the holotype (1: dorsal, 2: ventral). 3–5: aedeagus (3: dorsal view, holotype, 4: ventral view, holotype, 5: lateral view, paratype). Photos 1–2 by Uitsiann Ong. Published records. Taihoku [= Taipei ] ( Gentili 1979 ). Chipon [= Taitung County ]; Kaohsiung ; Heito [= Pintung County ]; Hualien ; Ilan [= Yilan ] ( Gentili 1989 , 1995 ); New Taipei ( Gentili 2003 ). Diagnosis. Body size 2.2–2.7 mm , body width 1.6–1.9 mm . Body oval ( Fig. 11 ). head black with preocular yellowish spots, Antennae with 8 antennomeres. Pronotum pale, with a large slightly metallic central dark spot ( Fig. 19 ). Elytra surface pale, with dense slightly irregular series of dark spots. Male genitalia ( Fig. 15 ): Aedeagus 0.7 mm long. Median lobe slender, rounded and membranous at apex; parameres much longer than median lobe, apex widely rounded and membranous, truncate inwards. Differential diagnosis. Laccobius formosus Gentili, 1979 is very similar to L. fragilis Nakane, 1966 , from which it only differs in the median lobe broadly rounded at apex. Distribution. China ( Gansu , Guandong, Guangxi , Hainan , Hubei , Hunan , Jiangxi , Liaoning , Sichuan , Shaanxi , Shandong ), Russia (Far East), Taiwan ( Fig. 27 ) ( Przewoźny 2020 , this paper). In Taiwan , L. formosus is distributed throughout the main island. Bionomics. All specimens were collected from stony streams ( Fig. 23 ).