taxonID	type	description	language	source
B75387965F44BF39FEF2FB42FD19F95D.taxon	diagnosis	Diagnosis. The genus can be distinguished from other hydrophilid genera occurring in Taiwan by the following combination of characters: body rather convex, brown to black (Fig. 1); eyes of moderate size, deeply excised internally; antenna with 9 antennomeres, antennal club loosely segmented; mesoventrite with arrow-head shaped median elevation; metaventrite longer than mesoventral elevation, with strongly raised median portion broadly projecting anteriorly and abutted to mesoventral process; elytra lacking serial punctures; sutural stria reaching basal half of elytra. Bionomics. All species inhabit moist environments, typically being found on gravely, sandy or muddy shores of rivers and pools. Some species live directly in shallow vegetated standing water (FIKÁČEK et al. 2019) and others are found on seepages and wet rocks with algae (JIA et al. 2014).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFC56FF43FBF3FAED.taxon	description	(Figs 2 A, 2 H, 3 D)	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFC56FF43FBF3FAED.taxon	materials_examined	Material examined. TAIWAN: TAITUNG: 1 (TARI): Lanyu (Ê Ṉ), 5. iv. 2011, Y. - T. Wang leg. HSINCHU: 7 spec. (HCLC): Beipu Township [ẍẘǿ], 24.707676 ° N 121.060744 ° E, 140 m, 1. vi. 2018, Hsing-Che Liu leg.; 2 (HCLC): same locality, 9. ix. 2019, Hsing-Che Liu leg. CHANGHUA: 4 (NMNS, HCLC): Huatan Township (Kñǿ), 24.030731 ° N 120.545094 ° E, 60 m, 3. xii. 2018, Hsing-Che Liu leg. TAINAN: 3 (HCLC): Guantian District [ĎOEdz], 23.182170 ° N 120.307721 ° E, 19. i. 2019, Hsing-Che Liu leg. PINGTUNG: 3 (CNUT): Nanjenshan (Ħ ḺƜ), 1. xii. 2018, Kai-Ying Zheng leg.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFC56FF43FBF3FAED.taxon	diagnosis	Diagnosis. Body length 4.8 – 5.2 mm, maximum body width 3.0 – 3.2 mm. Body oval, strongly convex, dorsal surface black to dark brown. Elytra surface densely punctate, without traces of series, sutural stria reaching basal half of elytra. Labrum black with yellow edges, its front margin deeply emarginate (Fig. 2 H). Mesofemora without dense pubescence. Male genitalia (Fig. 2 A): Median lobe bottle-shaped, narrowly rounded apically, strongly widened close to the base, gonopore situated subapically; parameres bent inwards in apical third, but not truncate apically. Differential diagnosis. Coelostoma fallaciosum is similar to C. vividum Orchymont, 1936 and C. vitalisi in genitalia morphology; it can be differentiated easily by the median lobe which is bottle-shaped and has the gonopore situated subapically.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFC56FF43FBF3FAED.taxon	distribution	Distribution. This species is known from China (Fujian, Guangdong, Hong Kong), Indonesia, Malaysia, Nepal, Taiwan (Fig. 4) and Vietnam (ORCHYMONT 1936; HANSEN 1999; JIA 2005 a; JIA et al. 2014, 2017; this paper). Bionomics. All examined specimens were collected from the surface of soil around a pond, perched on rotting aquatic plants (Fig. 3 D).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFF11FEF2FE5FF7A7.taxon	description	(Figs 2 E, 3 C)	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFF11FEF2FE5FF7A7.taxon	materials_examined	Material examined. TAIWAN: TAIPEI: 1 (TARI): Taihokn, Ankeng [% AE], 2. xi. 1941, S. Miyamoto leg.; 1 (TARI): Taihokn, 2. iv. 1940, S. Miyamoto leg. PENGHU: 1, 1 ♀♀ (NMNS): Makung [Ṛċ], 19. vi. 2000, C. - S. Lin & W. - T. Yang leg. TAICHUNG: 1 (HCLC): Wufeng District [Ẕḇdz], Tonglin Vill. [ṖIJm], 24.0768 ° N 120.7252 ° E, 110 m, 19. x. 2018, Hsing- Che Liu leg, at the edge of a stream, beneath a stone; 3 (HCLC): Wufeng District [Ẕḇdz], Tonglin Vill. [ṖIJm], 24.0768 ° N 120.7252 ° E, 110 m, 29. x. 2018, Hsing-Che Liu leg, at the edge of a stream, beneath a stone; 1 (HCLC): Wufeng District [Ẕḇdz], Tonglin Vill. [ṖIJm], 24.0768 ° N 120.7252 ° E, 110 m, 5. xi. 2018, Hsing-Che Liu leg, at the edge of a stream, beneath a stone. TAITUNG: 1 1 ♀ (NMNS): Lanyu Yurean [Ê Ṉĕƛ], III / 6 / 2012, Y. T. Wang (Ŧ ṪŽ). CHANGHUA: 3 spec. (HCLC): Fuxing Township [Ğ Ḅǿ], Fubao Village [Ğã], 24.046974 ° N 120.398450 ° E, 3 m, 24. xi. 2019, Hsing-Che Liu leg. KAOHSIUNG: 19 spec. (NCHU): Dongsha Island (ǥàƀ), 20.708 ° N, 116.71654 ° E, 21 – 25. iv. 2005, pitfall trap, leg. J. - F. Tsai, Z. - Y. Liu & B. - F. Chen (DE 03) [specimens NCHU 0007 - 1823 to NCHU 0007 - 1831]; 2 spec. (NCHU): Dongsha Island (ǥàƀ), 20.708 ° N, 116.71654 ° E, 21 – 25. iv. 2005, pitfall trap, leg. J. - F. Tsai, Z. - Y. Liu & B. - F. Chen (DE 02) [specimens NCHU 0007 - 1832 and NCHU 0007 - 1833]; 5 spec. (NCHU): Dongsha Island (ǥàƀ), 20.708 ° N, 116.716540 ° E, 26. iv. 2005, DE sample plot, leg. J. - F. Tsai, Z. - Y. Liu & B. - F. Chen, [specimens NCHU 0007 - 1834 to NCHU 0007 - 1838]; 7 spec. (NCHU): Dongsha Island (ǥàƀ), 20.708 ° N, 116.716540 ° E, 26. iv. 2005, DE sample plot, marsh, leg. J. - F. Tsai, Z. - Y. Liu & B. - F. Chen [specimens NCHU 0007 - 1839 to NCHU 0007 - 1845].	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFF11FEF2FE5FF7A7.taxon	diagnosis	Diagnosis. Body size 4.1 – 4.5 mm, body width 2.7 – 2.9 mm. Body oval. Labrum black with yellow edges, its front margin emarginate. Elytral surface densely punctate, without traces of series, sutural stria reaching basal half of elytra. Mesofemora with strong setae, but without dense pubescence. Abdominal ventrite V with row of stout setae situated in apical emargination. Male genitalia (Fig. 2 E): aedeagus 1.0 – 1.1 mm long. median lobe shorter than parameres, almost of the same width from base to apex, only slightly widened at the very base, apex subangulate; gonopore small, situated apically; parameres bent inwards in apical third, truncate apically. Differential diagnosis. This species is very similar to C. stultum, it can be distinguished from it by median lobe almost parallel-sided and slightly spoon-like, not distinctly widened basally.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFF11FEF2FE5FF7A7.taxon	discussion	Comments. It seems that this species was confused with C. stultum by previous authors. The concept of C. bhutanicum and C. stultum adopted here is based on the study of material from the Indian subcontinent (including the types of C. stultum from Sri Lanka) prepared as part of a study of the Indian Coelostoma by S. Sheth, H. Ghate and M. Fikáček and will be explained and justified in detail there. Bionomics. Specimens from Changhua and Taichung were collected among plant roots around a pond and in the mud on the river shore. All specimens from Donsha Island (Fig. 3 A) were collected by a pitfall trap which was set near a seasonal marsh.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3BFF11FEF2FE5FF7A7.taxon	distribution	Distribution. This species is so far only known from the Himalayas (India, Nepal and Bhutan) (FIKÁČEK et al. 2015). First record for Taiwan (Fig. 4).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3CFCB5FA7BFDCBF7A3.taxon	description	(Figs 2 C, 3 E)	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3CFCB5FA7BFDCBF7A3.taxon	materials_examined	Material examined. TAIWAN: TAITUNG: 1 (TARI): Hsiaotianchi (ṬXṮ), 2. iv. 2016, B. - X. Guo leg. YILAN: 2 (KMNH): ‘ Yijie (á ỡ) ʼ [incorrect spelling, correct name of the locality is Aijie (Ṟỡ)], Yunshan Township [DƜǿ], 12 – 14. ix. 2000, Takashi Shimada leg.; 2, 6 ♀♀ (NMNS): Jiaoxi Township [ḌṰǿ], Tangwei Brook Park [ȁā ặảợċă], 24 ° 49 ' 41.9 " N 121 ° 46 ' 12.4 " E, 22. iv. 2018, F. S. Hu leg., hand collecting; 5 (HCLC): Jiaoxi Township [ḌṰǿ], 24.824385 ° N 121.769800 ° E, 2. vii. 2019, Hsing-Che Liu leg; 26 spec. (HCLC): Luodong sports park (ůǥ ḋḙċă), Luodong To. [ůǥ ḃ], 24.6841 ° N, 121.7517 ° E, 19. i. 2020, leg. F. S. Hu (near pond). HSINCHU: 1 (HCLC): Emei Township [Ŕ Ḏǿ], 11. ix. 2018, Hsing-Che Liu leg; TAIPEI: 1, 1 ♀♀ (NMNS): NTU Farm [ȒŘR Ḥōö], 22. ix. 2011, Y. T. Wang (Ŧ ṪŽ).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F46BF3CFCB5FA7BFDCBF7A3.taxon	diagnosis	Diagnosis. Body length 5.2 – 5.5 mm, maximum body width 3.2 – 3.3 mm. Body black. Labrum yellowish. Maxillary and labial palpi yellowish. Elytra densely punctate, without traces of series, sutural stria reaching basal half of elytra. Ventral face of pro- and mesofemora densely pubescent. Male genitalia (Fig. 2 C). Aedeagus 1.5 mm long, apical part of the median lobe trilobed apically, much shorter than parameres; gonopore semicircular; apical third of the paramere bends inwards. Differential diagnosis. Coelostoma phallicum is unique among Taiwanese Coelostoma in having the median lobe trilobed apically. Bionomics (Fig. 3 E). The specimens of C. phallicum from Yilan were found in mud with abundant Brassica plants and from accumulations of rotten leaves in a small, artificial brook draining the water from a hot spring hotel. They were found either submerged in water or on the border of the shore zone of the stream. The specimen from Hsinchu was collected from the surface of a wet stone near the stream. The beetles were observed active at night. Distribution. This species is known from China (Guangdong, Hainan, Guangxi), Cambodia, Indonesia, Malaysia, Laos and Vietnam (ORCHYMONT 1940, HANSEN 1999, JIA et al. 2014). New record for Taiwan (Fig. 4).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F41BF3DFC21FA1AFB36FA1F.taxon	description	(Figs 2 F, 3 A) Hydrobius stultus Walker, 1858: 209.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F41BF3DFC21FA1AFB36FA1F.taxon	materials_examined	Material examined. TAIWAN: HSINCHU: 1 1 ♀ (HCLC): Zhudong [Űǥ ḃ], 28. viii. 2018, 24.784950 ° N 121.036672 ° E, 83 m, Hsing-Che Liu leg. JAPAN: YAEYAMA ISL.: 1, 1 spec. (NMPC): Iriomote Is., 28. vi. 1981, S. Morita lgt. [this specimen was used to illustrate the genitalia of C. stultum in Fig. 2 F].	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F41BF3DFC21FA1AFB36FA1F.taxon	diagnosis	Diagnosis. Body size 5.4 – 5.7 mm, body width 3.0 – 3.2 mm. Body oval. Labrum black with yellow edges, its front margin emarginate. Elytral surface densely punctate, without traces of series, sutural stria reaching basal half of elytra. Mesofemora with strong setae, but without dense pubescence. Abdominal ventrite V with row of stout setae situated in apical emargination. Male genitalia (Fig. 2 F): aedeagus 0.8 – 0.9 mm long. Median lobe shorter than parameres, wide basally, narrowing towards midlength, apical half narrowly parallelsided, rounded apically; gonopore wide, situated apically; parameres bent inwards in apical third, truncate apically. Differential diagnosis. This species differs from other Taiwanese species except C. bhutanicum in the following combination of characters: mesofemora without dense pubescence and the apical portion of abdominal ventrite 5 with a shallow emargination possessing stout setae (i. e. diagnostic characters of Holocoelostoma). It can be distinguished from C. bhutanicum by having the median lobe wide in the basal half and not spoon-like in shape. In contrast to C. bhutanicum, specimens of C. stultum are slightly larger but with a relatively smaller and less sclerotized aedeagus. Bionomics. Both examined specimens from Taiwan were found in rotten rice stems near a rice field (Fig. 3 A).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F41BF3DFC21FA1AFB36FA1F.taxon	distribution	Distribution. China (Chongqing, Fujian, Guangxi, Guangdong, Hainan, Jiangxi, Sichuan, Yunnan, Xizang), Andaman Is., India, Indonesia, Japan, Malaysia, Mascarene Is., Myanmar, Nicobar Is., Oman, Philippines, Saudi Arabia (south), South Korea, Sri Lanka, Taiwan, Thailand, United Arab Emirates, Vietnam (JIA et al. 2014, 2017; this paper). Some of these records may actually refer to C. bhutanicum (see above under that species).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F43BF3EFF2BF948FDC7F7A3.taxon	discussion	Comments. Coelostoma vagum was reported from Taiwan (without specified locality) by JIA (2005 b), but the respective specimen from the Hokkaido University Museum is lost (A. L. Suzumura, pers. comm. 2019). The aedeagus of the species resembles that of C. taiwanense sp. nov. and it is hence possible that this record in fact refers to that species. We remove this species from the Taiwanese fauna at the moment, until the vouchers or fresh specimens from Taiwan are available.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F43BF3EFF3AFDD2FD5DF981.taxon	description	(Figs 2 D, 3 B)	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F43BF3EFF3AFDD2FD5DF981.taxon	materials_examined	Material examined. TAIWAN: PINGTUNG: 2 (TARI): v. 1933, Y. Miwa leg.; 2 (TARI): Neipu Township (H ẘǿ), 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.	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F43BF3EFF3AFDD2FD5DF981.taxon	diagnosis	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. 2 D). 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. 3 B).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
B75387965F43BF3EFF3AFDD2FD5DF981.taxon	distribution	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).	en	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): 155-162, DOI: 10.37520/aemnp.2020.008
