Coelostoma (Lachnocoelostoma) wui Orchymont, 1940

Liu, Hsing-Che, Hu, Fang-Shuo & Fikáček, Martin, 2020, Review of the genus Coelostoma of Taiwan with description of a new species (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 155-162 : 161

Coelostoma (Lachnocoelostoma) wui Orchymont, 1940

( Figs 2D , 3B )

Coelostoma wui Orchymont, 1940: 160 .

Material examined. TAIWAN: PINGTUNG: 2 ( TARI): v.1933, Y. Miwa leg.; 2 ( TARI): Neipu Township (Hẘǿ), 7.v.2014, Y.-T. Chung leg.; 6 spec. ( TARI): Wanluan (ḆĤ), 5.xii.2017, Y.-T. Chung leg. HSINCHU: 4 ( NMNS, HCLC): Hengshan Township [ḒƜǿ], 24.713662°N 121.141443°E, 120 m, 8.iii.2019, Hsing-Che Liu & Ryosuke Matsushima leg.

Diagnosis. Body length 5.2–5.8 mm, maximum body width 3.2–3.5 mm. Head black. Labrum yellowish. Maxillary palpi, labial palpi yellowish. Pronotum blackish brown, with broad yellowish lateral margins. Elytra black, densely punctate, without traces of series, sutural stria reaching basal half of elytra. Ventral face of pro- and mesofemora pubescent, except at extreme apex.

Male genitalia ( Fig. 2D ). Aedeagus 1.8 mm long. Median lobe much shorter than parameres, slightly widening from base to apex, apex widely rounded; gonopore subtriangular, situated subapically; parameres widened and parallel-sided in apical third.

Differential diagnosis. The aedeagus of this species is very long and hence similar to C. vagum and C. taiwanense sp. nov. Coelostoma wui can be distinguished from both the latter species by having the parameres widened and nearly parallel-sided in their apical third, and by the apex of the median lobe being rounded.

Bionomics. The specimens were found under the stones on the border of streams ( Fig. 3B ).

Distribution. This species is known from China (Hubei, Hunan, Jiangxi, Shaanxi, Shandong) and Korea ( HANSEN 1999, JIA et al. 2014). New record for Taiwan ( Fig. 4 ).

Figures

Fig. 2. male genitalia and front view of the head of Taiwanese Coelostoma species.A–F – genitals in dorsal view:A – C. fallaciosum Orchymont, 1936; B – C. vitalisi Orchymont, 1923; C – C. phallicum Orchymont, 1940; D – C. wui Orchymont, 1940; E – C. bhutanicum Jayaswal, 1972; F – C. stultum (Walker, 1858), specimen from Japan: Iriomote Island; G–H – front view of head with labrum: G – C. taiwanense sp. nov., paratype; H – C. fallaciosum.

Fig. 3. Habitat of Coelostoma species.A – Hsinchu County, Zhudong: habitat of C. stultum (Walker, 1858); B – Hsinchu County, Hengshan Township: habitat of C. wui Orchymont, 1940; C – Taichung City, Wufeng District:habitat of C. taiwanense sp.nov.and C. bhutanicum Jayaswal, 1972; D – Hsinchu County, Beipu Township: habitat of C. fallaciosum Orchymont, 1936; E – Yilan County, Jiaoxi Township: habitat of C. phallicum Orchymont, 1940; F – Taipei city, Neihu District: habitat of C. vitalisi Orchymont, 1923. Photos by H.-C. Liu (A–C, F), R. Matsushima (D) and F.-S. Hu (E).

Fig. 4. Map of Taiwan showing distribution of species of the Coelostoma species.