Laccobius (Glyptolaccobius) politus Gentili, 1979

Liu, Hsing-Che & Fikáček, Martin, 2021, Review of the Taiwanese Laccobius Erichson, 1837 (Coleoptera: Hydrophilidae) with description of a new species, Zootaxa 4963 (3), pp. 587-599 : 594

Laccobius (Glyptolaccobius) politus Gentili, 1979 光澤flǿ牙ḃ

( Figs 10, 14 , 26 )

Laccobius (Microlaccobius) politus Gentili, 1979: 46 .

Laccobius (Cyclolaccobius) politus: Gentili (1995: 257) ; Gentili (2003: 414); Hansen (1999: 132).

Oocyclus flaveolus Hebauer & Wang, 1998: 41 . Synonymized with L. politus by Gentili (2012).

Laccobius (Glyptolaccobius) politus: Jia et al (2019: 72) .

Material examined. TAIWAN: NANTOU: 7 spec., ( NMPC): 5.5 km SSW of Heshe at Rd. 07 23.55263°N 120.86947°E, 1070m. 16.V.2018. Fikáček, Liang, Liu & Minoshima. (2018-TW37) ; 15 spec., ( NMPC): wet concrete wall at Kaigao Rd. 4.25 km SE of Heshe; 23.5641°N 120.91837°E. 15.V.2018. Fikáček, Liang, Liu & Minoshima. (2018-TW34) ; CHIAYI: 1 spec., ( NMPC): track down to Yuntan waterfall 3.5 km W of Meishan township 23.5327417, 120.6557500; 850m 1.v.2019; Damaška, Fikáček, Liu & Tkoč lgt. (2019-TW13) . NEw TAIPEI: 1 male, 3 spec. ( HCLC, NCHU): Pingxi District, Wanggu Waterfall [望古瀑布], 30.III.2020. on the wet rock, Hsing-Che Liu leg. HSINCHU: 2 males, 5 spec., ( HCLC): Emei Township [峨眉ė], Qixing Village [七ffl村], 24.656664°N 121.023909°E, 151m, 24.VIII.2020. on wet rock, Hsing-Che Liu leg. TAICHUNG: Heping distr, Bashianshan Mts., beginning of Bashianshan Forest Rd. , 5.i.2018 24.19808°N 121.00115°E, 722 m, exposed wet concrete/stony wall at side of the road, Fikáček, Liang, Hsiao (2018-TW03) .

Published records: New Taipei ( Gentili 1979, 2003; Hebauer & Wang 1998); Hualien ( Gentili 1995); Keelung, Kaohsiung ( Hebauer & Wang 1998); Nantou ( Gentili 2003, 2012).

Diagnosis. Body length 1.8–2.0 mm, maximum body width 1.2–1.3 mm. Body oval ( Fig. 10 ), strongly convex. Dorsal back, pronotum and elytra with lateral dark brown margin. Surface of pronotum and elytra with sparse white setae. Legs brown. Male genitalia ( Fig. 14 ): Aedeagus 0.5 mm long. Median lobe slender, wide basally, slightly narrowing towards midlength, apical rounded; parameres slightly shorter than median lobe or as long as median lobe, weakly narrowing at apex, narrowing towards basal, basal truncate.

Differential diagnosis. Laccobius politus is similar to Chinese species of L. hainanensis Jia, Gentili & Fikáček, 2013 , L. martini Jia, Song & Gentili, 2013 and L. motuoensis Jia, Chen & Fikáček, 2019 . It can be differentiated from them by the dorsal surface with sparse white setae, median lobe indistinctly constricted subapically, and parameres narrower than median lobe, rounded apically. This species is the only inhabitant of wet rocks in Taiwan, as well as that only representative of the subgenus Glyptolaccobius in Taiwan. Therefore, this species can be easily distinguished from other Taiwanese species.

Distribution. China (Yunnan), Nepal, Taiwan ( Fig. 27 ) ( Gentili 1979; Gentili 2003; Hebauer 2006; Jia et al. 2013, this paper).

Bionomics. All examined specimens were collected on wet rocks ( Fig. 26 ).

Figures

FIGURES 27. Map of Taiwan showing the distribution of the Laccobius species.

FIGURES 10–18. Dosal view of the habitus and male genitalia of Taiwanese Laccobius species (10–13: habitus, 14–18: male genitalia). 10, 14: L. politus Gentili, 1979. 11, 15: L. formosus Gentili, 1979. 12, 16: L. hammondi Gentili, 1984. 13, 17: L. roseiceps Régimbart, 1903. 18: L. fragilis Nakane, 1966, after Nakane (1966).

FIGURES 23–26. Habitat of Taiwanese Laccobius species. 23: Nantou County, Puli: habitat of L. formosus. 24: Taichung City, Wufeng: habitat of L. hammondi and L. hoi sp. nov. 25: Pingtung County, Ligang: habitat of L. formosus, L. hoi sp. nov. and L. roseiceps. 26: New Taipei City, Pingxi: habitat of L. politus.