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Cybister laevis Falkenström, 1936 (Figs 5A–C; 20A) Cybister laevis Falkenström, 1936: 243 (orig. descr.). Cybister tripunctatus var. laevis: GSCHWENDTNER (1938: 64). Type material. HOLOTYPE: ♀ (NHRS), labelled: “Giufu-Shan [Chongqing, Jinfoshan Mt.] / Szechuan / Em. Reitter [p] // Cybister ♀ / laevis / Falk. [hw] / det. Falkenström [p] // Typus [red label with black frame, p] // 7533 / E91 + [blue label, p] // NHRS-JLKB / 000073974 [p]”. Diagnosis. See Cybister tripunctatus lateralis. Ventral side yellowish. Comments to classification. The female type specimen has smooth elytra without any striolae – a condition which can be observed also in all females of C. tripuncatus lateralis. Since it is an odd, old museum specimen, it has a yellowish ventral side, which is not the case for C. tripunctatus lateralis from China, where the ventral side is always black or ferruginous in freshly hatched specimens. The size (26 mm) and the coloration of the dorsal side also indicate that C. laevis is conspecific with the variable and widespread C. tripunctatus lateralis, as already suggested by GSCHWENDTNER (1938). Distribution. China (Chongqing) (Fig. 20A)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Mai, Zu-Qi, Jia, Feng-Long & Hendrich, Lars, 2023, Review of the genus Cybister in China, with description of a new species from Guangdong (Coleoptera: Dytiscidae), pp. 75-102 in Acta Entomologica Musei Nationalis Pragae 63 (1) on page 80, DOI: 10.37520/aemnp.2023.003, http://zenodo.org/record/7887332, {"references":["FALKENSTROM G. 1936: Halipliden, Dytisciden und Gyriniden aus West- und Zentral-China (Coleoptera). Lingnan Science Journal 15: 225 - 248.","GSCHWENDTNER L. 1938: Monographie der palaarktischen Dytisciden. IX. Dytiscinae. Koleopterologische Rundschau 24: 33 - 76."]}

Cybister bengalensis Aubé, 1838 (Figs 1A–E) Cybister bengalensis Aubé, 1838: 61 (orig. descr.). Material examined. CHINA: JIANGXI: 1 ♀, Pingshiang [Pingxiang], coll.A.Zimmermann (ZSMG). TAIWAN: 2JJ, Formosa,coll.A.Zimmermann (ZSMG); 1 J, Ku Sia, coll. A. Zimmermann (ZSMG). WITHOUT ඉRECISE DATA: 1 ♀, China, coll. A. Zimmermann (ZSMG)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Mai, Zu-Qi, Jia, Feng-Long & Hendrich, Lars, 2023, Review of the genus Cybister in China, with description of a new species from Guangdong (Coleoptera: Dytiscidae), pp. 75-102 in Acta Entomologica Musei Nationalis Pragae 63 (1) on page 76, DOI: 10.37520/aemnp.2023.003, http://zenodo.org/record/7887332, {"references":["AUBE C. 1838: Species general des hydrocanthares et gyriniens; pour faire suite au species general des coleopteres de la collection de M. le comte Dejean. Mequignon Pere et Fils, Paris, xvi + 804 pp."]}

Subgenus Cybister Curtis, 1827 Type species. Dytiscus lateralis Fabricius, 1798. Diagnosis. With distinctive yellow margins laterally on the pronotum and elytron. Males with a single claw per metatarsus; females usually with single claws, except in some North and Central American species. Included (Chinese) species. Cybister bengalensis Aubé, 1838; C. chinensis Motschulsky, 1854; C. fumatus Sharp, 1882; C. guerini Aubé, 1838; C. laevis Falkenström, 1936; C. lateralimarginalis torquatus (Fischer von Waldheim, 1829); C. lewisianus Sharp, 1873; C. limbatus (Fabricius, 1775); C. rugosus (W. S. Macleay, 1825); C. tripunctatus lateralis (Fabricius, 1798); C. ventralis Sharp, 1882., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Mai, Zu-Qi, Jia, Feng-Long & Hendrich, Lars, 2023, Review of the genus Cybister in China, with description of a new species from Guangdong (Coleoptera: Dytiscidae), pp. 75-102 in Acta Entomologica Musei Nationalis Pragae 63 (1) on page 76, DOI: 10.37520/aemnp.2023.003, http://zenodo.org/record/7887332, {"references":["FABRICIUS J. C. 1798: Supplementum entomologiae systematicae. C. G. Proft et Storch, Hafniae, 4 + 572 pp.","AUBE C. 1838: Species general des hydrocanthares et gyriniens; pour faire suite au species general des coleopteres de la collection de M. le comte Dejean. Mequignon Pere et Fils, Paris, xvi + 804 pp.","MOTSCHULSKY V. DE 1854: Diagnoses de coleopteres nouveaux, trouves par M. M. Tatarinoff et Gaschkewitsch aux environs de Pekin. Etudes Entomologiques 2 (1853): 44 - 51.","SHARP D. 1882: On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Dublin Society, Series II 2: 179 - 1003 + pls 7 - 18.","FALKENSTROM G. 1936: Halipliden, Dytisciden und Gyriniden aus West- und Zentral-China (Coleoptera). Lingnan Science Journal 15: 225 - 248.","FISCHER VON WALDHEIM G. 1829: Museum historiae naturalis Universitatis Caesareae Mosquensis. Pars II, Insecta. Typis Universitatis Caesareae, Mosquae, 147 pp.","SHARP D. 1873: The water beetles of Japan. Transactions of the Entomological Society of London 1873: 45 - 67.","FABRICIUS J. C. 1775: Systema entomologiae, sistens Insectorum classes, ordines, genera, species adiectis synonymis, locis, descriptionibus, observationibus. Libraria Korte, Flensburgi et Lipsiae, xxxii + 832 pp.","MACLEAY W. S. 1825: Annulosa Javanica, or an attempt to illustrate the natural affinities and analogies of the insects collected in Java by Thomas Horsfield, M. D. F. L. & G. S. and deposited by him in the museum of the honourable East-India Company. Number I. Kingsbury, Parbury & Allen, London, xii + 50 pp. + 1 pl."]}

Subgenus Melanectes Brinck, 1945 Type species. Cybister owas Laporte, 1835. Diagnosis. Without distinctive yellow or pale margins on the elytron and pronotum. Males with a single metatarsal claw; females with two claws, the posterior claw small. Included (Chinese) species. Cybister brevis Aubé, 1838; C. convexus Sharp, 1882; C. danxiaensis sp. nov.; C. posticus Aubé, 1838; C. sugillatus Erichson, 1834., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Mai, Zu-Qi, Jia, Feng-Long & Hendrich, Lars, 2023, Review of the genus Cybister in China, with description of a new species from Guangdong (Coleoptera: Dytiscidae), pp. 75-102 in Acta Entomologica Musei Nationalis Pragae 63 (1) on page 91, DOI: 10.37520/aemnp.2023.003, http://zenodo.org/record/7887332, {"references":["BRINCK P. 1945: Nomenklatorische und systematische Studien uber Dytisciden. III. Die Klassifikation der Cybisterinen. Kungliga Fysiografiska Sallskapets Handlingar 56 (4): 1 - 20.","AUBE C. 1838: Species general des hydrocanthares et gyriniens; pour faire suite au species general des coleopteres de la collection de M. le comte Dejean. Mequignon Pere et Fils, Paris, xvi + 804 pp.","SHARP D. 1882: On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Dublin Society, Series II 2: 179 - 1003 + pls 7 - 18.","ERICHSON W. F. 1834: Coleoptera. In: MEYEN F. J. F. (ed.): Beitrage zur Zoologie, gesammelt auf einer Reise um die Erde. Nova Acta Academiae Caesareae Leopoldino-Carolinae Germanicae Naturae Curiosorum 16 (Supplement 28): 219 - 276."]}

Platynectes kashmiranus lemberki Šťastný, 2003 (Figs 4A–B, 7C–E, 9B, 12A) Platynectes kashmiranus lemberki Šťastný, 2003: 230 (orig. descr.). Platynectes kashmiranus J. Balfour-Browne, 1944: Nilsson 1998: 117 (China, Yunnan). Type locality. “ China, Yunnan Province, 10 km NE of Tengchong, Behai ZingHai lake env”. Type material. Holotype ♂, deposited in NHMW. Material examined. CHINA: Xizang: 2 ♀, Mêdog, Beibeng, 850 m, 25.v.1983, Y. Han leg. (SYSU); 1 ♂, 1 ♀, Linzhi, Mêdog, A’ni Bridge, 1080 m, 13.viii.2006, M. Bai leg. (SYSU); 1 ♂, Mêdog County, Dexing Township 29°19′56″N, 95°18′24″E, 887 m, 22.vi.2018, S. Wang & Z. Liang leg. (SYSU); 3 ♂, 1 ♀, Mêdog County, Miri Village, 29°25′6″N, 95°24′23″E, 820 m, 23.vi.2018, S. Wang & Z. Liang leg. (SYSU); Yunnan: 3 ♂, 3 ♀, Baoshan, Baihualing, Zaotang River, 25.3087N, 98.7936E, 1480 m, 11.v.2021, Z. Jiang, Z. Yang, Z. Mai & B. Huang leg. (SYSU); 3 ♂, 4 ♀, Tengchong, Houqiao Town, Y015, 25.2281N, 98.2985E, 1750 m, 12.v.2021, Z. Jiang, Z. Yang & Z. Mai leg. (SYSU); 1 ♀, Tengchong, Houqiao Town, Xintang River, 25.1599N, 98.2450E, 1890 m, 12.v.2021, Z. Jiang, Z. Yang & Z. Mai leg. (SYSU); 13 ♂, 6 ♀, Lushui, Pianma Town, S 316, 26.0143N, 98.6506E, 2135 m, 17.v.2021, Z. Jiang, Z. Yang & Z. Mai leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 4A–B and 7C–E. Collection details. The specimens from Pianma Town were collected among gravel in a crevice at the bottom of a wet rock wall (Fig. 9B). Distribution. Southern China (Yunnan, Xizang) (Fig. 12A). First record from Xizang Autonomous Region. Notes. The median lobe of the specimens from Xizang (Fig. 7D) is similar to that of P. kasmiranus lemberki specimens from Yunnan (Fig. 7C) but more strongly curved. The geographical conditions between Xizang and Yunnan are very different, so the differences are understandable. Except for curvature of the median lobe, no other distinct differences were found between the specimens from Xizang and Yunnan., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on pages 409-410, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Balfour-Browne, J. (1944) New names and new synonymies in the Dytiscidae (Col.). The Annals and Magazine of Natural History, Series 11, 11 (78), 345 - 359. https: // doi. org / 10.1080 / 00222934408527440","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121."]}

Platynectes nanlingensis Šťastný, 2003 (Figs 5A, 7H–I, 12B) Platynectes nanlingensis Šťastný, 2003: 236 (orig. descr.). Platynectes dissimilis dissimilis (Sharp, 1873): Nilsson 1998: 111 (partim, #208 Wuyi Shan). Type locality. “ China, Guangdong Province, Nanling N. P., Yao Shan”, ca. 24°53′03″N, 112°57′37″E, 950 m. Type material. Holotype ♂, deposited in IAECAS. Material examined. CHINA: Guangdong: 1 ♂, “ Guangdong Prov., Chengjia-Ruyuan rd. ca. 40 km E Chengjia 5.11.2001 Jäch & Komarek (CWBS 471)” (JSCL); Jiangxi: 1 ♂, Jinggangshan Mt., Jingzhushan Scenic Area, 910 m, 25.iv.2011, S. Zhao leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 5A and 7H–I. Collection details. Found in streams at moderate altitude (400–500 m a.s.l.) (Šťastný 2003). Distribution. Southeastern China (Fujian, Guangdong, Jiangxi) (Fig. 12B). First record from Jiangxi province., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 415, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Sharp, D. (1873) The water beetles of Japan. The Transactions of the Entomological Society of London, 1873, 45 - 67. https: // doi. org / 10.1111 / j. 1365 - 2311.1873. tb 00636. x","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121."]}

Platynectes pangu sp. nov. (Figs 1B, E–F, 9D, 12B) Type locality. China, Yunnan Province, Lvchun County, Huanglianshan Reservoir, ca. 22.8898N, 102.2952E, 1720 m. Type material. Holotype ♂ (SYSU), labelled: “ ř南ḂữƀhĦḖƜṁw / 22.8898N,102.2952E / 1717.3 m, 2021.IV.30 / ƃfflDz,KflM,RDZƛ,ĦÍṮ [p] // CHINA: Yunnan Province / Lvchun County / Huanglianshan Reservoir / 22.8898N, 102.2952E / 1717.3 m, 30.iv.2021 / Z. Jiang, Z. Yang, Z. Mai & / B. Huang leg. [p] // HOLOTYPE / PLATYNECTES / pangu sp. nov. / Jiang, Jia & Šťastný det. 2022 [red label, p]”. Paratypes: 18 ♂, 5 ♀, same label data as holotype and with respective paratype labels (SYSU). Description of male holotype. Habitus (Fig. 1B) oblong-oval, with continuous outline, broadest before middle of elytral length, moderately convex. Dorsal surface slightly matt due to distinct reticulation. Colouration. Head orange-brown, with black triangular spots on frons between eyes, antero-lateral part to eyes and vertex reddish-brown; pronotum black with anterior angles and lateral margins orange-brown, anterior margin and transverse medial band reddish-brown; elytra black with yellow transverse basal fascia and with eight longitudinal vittae; appendages reddish-brown; ventral side black with reddish-brown spot on each side of abdominal ventrites II–IV. Head. Moderately broad, ca. 0.65× width of pronotum. Anterior margin of clypeus semicircular, with pair of sublateral foveae. Antenna with antennomeres long and slender. Eyes emarginate anterolaterally. Punctation double; several coarse setigerous punctures present in fronto-clypeal grooves and in depressions along inner margin of eyes; fine punctures distributed sparsely and irregularly on head surface, mainly at intersections of reticulation. Reticulation deeply impressed consisting of heterogeneous, somewhat elongate, polygonal meshes; most meshes closed, usually with several micropunctures inside. Pronotum. Transverse (width/length ratio = 3.5), broadest between posterior angles. Sides moderately curved, with distinct bead. Anterior margin nearly straight, posterior margin slightly sinuate. Punctation double, similar to that of head; rows of coarse setigerous punctures present along anterior margin and lateral parts of basal margin; fine punctures distributed irregularly on pronotal surface, mainly at intersections of meshes. Reticulation similar to that of head, on disc meshes larger and less impressed, sometimes not closed, near sides becoming much smaller and more deeply impressed. Centre of disc with small indistinct longitudinal furrow. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra moderately curved. Yellow transverse fascia presents at base of elytra, interrupted only sublaterally. Eight yellow longitudinal vittae present on each elytron: vitta 1 almost continuous, vittae 2–7 formed by series of dots, vitta 8 continuous, vitta 5 bifurcate anteriorly; all vittae beginning at transverse basal fascia and ending at apex. Punctation double; coarse setigerous punctures present along vittae 1, 3, 5, 7 and lateral margins of elytra; fine punctures distributed irregularly over elytral surface, mainly at intersections of reticulation. Reticulation well impressed, similar to that of head and pronotum, meshes usually with several micropunctures inside, sometimes not closed. Legs. Meso- and metafemora with tuft of spiniform setae along ventral margin of anteroapical angle. Pro- and mesotibia broadened, club shaped, densely punctured with spinigerous punctures over ventral surface. Metatibia with two lines of coarse spinigerous punctures on ventral surface. Pro- and mesotarsomeres 1–3 moderately broadened, with adhesive setae on ventral side; claws simple. Metatarsal claws subequal; anterior claw slightly shorter than posterior one. Surface of legs with distinct reticulation consisting of elongate meshes. Ventral side. Anterior margin of prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, with distinct lateral bead in basal half, apex pointed; surface with irregular sparse double punctation. Medial part of metaventrite without microsculpture, shiny, with sparse fine punctation; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender, reaching lateral margins. Metacoxal lines distinct, well impressed, subparallel anteriorly, divergent posteriorly. Metacoxal plates covered with shallow transverse wrinkles; reticulation consisting of polygonal meshes, punctation consisting of sparse fine punctures. Conjoint posterior margin of metacoxal processes slightly concave. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I, oblique on ventrite II and transverse on ventrites III–V; ventrites III–V additionally with numerous fine transverse wrinkles medially. Punctation double; ventrites III–V with setigerous punctures arranged sparsely in transverse line in medial part and with one coarser setigerous puncture presents in the middle; fine punctures distributed sparsely and irregularly on ventrite surface. Abdominal ventrite VI with sublateral rugose area comprising more than 10 deep longitudinal grooves on each side; reticulation present only baso-laterally; punctation double, coarse setigerous punctures present along posterior margin, fine punctures distributed densely on middle part. Male genitalia. Median lobe of aedeagus in lateral view strongly curved; strongly broadened in apical fifth, with distinct setae subapically along both ventral and dorsal margins; apex rounded, bevelled on both dorsal and ventral sides (Fig. 1E). Parameres slender, with dense setae dorsally, with distinct subbasal tooth on ventral side (Fig. 1F). Female. Identical to male in habitus. Meshes of dorsal surface reticulation more deeply impressed and longitudinally stretched; in some specimens reticulation consists of extremely dense meshes, all meshes closed, elongate mainly on elytra; surface appearing more matt. Abdominal ventrite VI without deep longitudinal grooves sublaterally. Pro- and mesotibia less broadened; pro- and mesotarsomeres not broadened, without adhesive setae ventrally. Variability. All specimens of the type series are rather uniform, being variable in body size. Ventrite II sometimes without reddish-brown spot on each side. Measurements. TL: 7.3–8.2 mm (mean value: 7.8 ± 0.1 mm); holotype: 7.8 mm. TL-h: 6.6–7.5 mm (mean value: 7.1 ± 0.1 mm); holotype: 7.2 mm. MW: 4.2–4.8 mm (mean value: 4.5 ± 0.1 mm); holotype: 4.6 mm. Differential diagnosis. The new species can be easily distinguished from other Chinese Platynectes by its large size. In terms of habitus, P. pangu sp. nov. is similar to another large species P. njai Brancucci, 2008 from Laos; however the shape of median lobe is distinctive: in both species, strongly broadened in apical fifth, but with apex widely rounded (see Brancucci 2008, Figs 2–3) in P. njai and rounded but bevelled on both dorsal and ventral sides in P. pangu sp. nov.. Collection details. Except for one specimen collected by light trap, all other type specimens were collected in a puddle on the bottom of spillway of the Huanglianshan reservoir (Fig. 9D). Etymology. The species name “ pangu ” refers to a giant in ancient Chinese mythology, representing the large size of the species of subgenus Gueorguievtes Vazirani, 1976. The species name is a noun standing in apposition. Distribution. So far known only from the type locality in Huanglianshan Mt., southern Yunnan, China (Fig. 12B). Notes. Brancucci (2008) described a large-sized species P. njai from Laos. He was pretty sure that the two large female specimens from Yunnan (Naturhistorisches Museum Wien) cited by Nilsson (1998) were not conspecific with P. njai. According to the information provided by Nilsson (1998) and Šťastný (2003), these two females probably belong to P. pangu sp. nov.

[Platynectes kashmiranus kashmiranus J. Balfour-Browne, 1944] Notes. This subspecies was mentioned from China (Tibet and Yunnan) by Nilsson (1998). The record of Tibet was based on some specimens labelled “Tibet-Nepal border, Kodari, Tatopani”. The locality actually belongs to Nepal and not Xizang in China. Šťastný (2003) just followed the Nilsson’s record but without studying any other specimens from Xizang. On the other hand, the specimens from Baoshan (Yunnan) studied by Nilsson (1998) were treated as a new subspecies— P. kashmiranus lemberki by Šťastný (2003). Therefore, we remove P. kashmiranus kashmiranus from the Chinese fauna., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 409, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Balfour-Browne, J. (1944) New names and new synonymies in the Dytiscidae (Col.). The Annals and Magazine of Natural History, Series 11, 11 (78), 345 - 359. https: // doi. org / 10.1080 / 00222934408527440","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121.","Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259."]}

Key to Chinese species of the genus Platynectes Régimbart 1 Elytra with or without yellow transverse basal fascia, without longitudinal vittae................................... 2 - Elytra with transverse basal yellow fascia and eight longitudinal vittae........................................... 5 2 Elytra with yellow transverse basal fascia (Fig. 5B).................................. Platynectes rihai Šťastný, 2003 - Elytra without yellow transverse basal fascia............................................................... 3 3 Size larger (TL: 6.4–7.0 mm); elytra without yellow preapical spots (Fig. 3D); median lobe of aedeagus subapically moderately broadened (Fig. 7A)..................................................... Platynectes hainanensis Nilsson, 1998 - Size smaller (TL: 4.9–6.0 mm); elytra with yellow preapical spots; median lobe of aedeagus subapically slightly or not broadened................................................................................................ 4 4 Size larger (TL: 5.4–6.0 mm), body moderately convex, elongate oblong oval (Fig. 2A); median lobe of aedeagus subapically not broadened, apex pointed (Fig. 6A)............................................... Platynectes babai Satô, 1982 - Size smaller (TL: 4.9–5.5 mm), body distinctly more convex, broadly oval (Fig. 2B); median lobe of aedeagus subapically slightly broadened, apex rounded (Fig. 6C)............. Platynectes davidorum Hájek, Alarie, Šťastný & Vondráček, 2019 5 Median lobe of aedeagus subapically constricted before broadened and widely truncate rounded apex (Figs 7C–D)..................................................................... Platynectes kashmiranus lemberki Šťastný, 2003 - Median lobe of aedeagus subapically not constricted, apex rounded or pointed..................................... 6 6 Size larger (TL: 6.4–8.2 mm); median lobe of aedeagus subapically moderately to strongly broadened.................. 7 - Size smaller (TL: 5.2–6.5 mm); median lobe of aedeagus subapically slightly or not broadened....................... 8 7 Elytron with transverse basal fascia narrow, interrupted laterally (Fig. 1B); median lobe of aedeagus strongly broadened in apical fifth, with apex rounded, bevelled on both dorsal and ventral sides (Fig. 1E)............... Platynectes pangu sp. nov. - Elytron with transverse basal fascia broad, uninterrupted and broadened laterally (Fig. 4D); median lobe of aedeagus in apical quarter markedly bent, moderately broadened, apex rounded (as in Šťastný 2003, Fig. 25).................................................................................................... Platynectes mazzoldii Šťastný, 2003 8 Median lobe of aedeagus with distinct protuberance near apex of basal piece on dorsal side, apical region elongate, apex rounded............................................................................................. 9 - Median lobe of aedeagus without distinct protuberance near apex of basal piece on dorsal side, apical region not elongate, apex rounded to bluntly pointed............................................................................. 10 9 Apical quarter of median lobe of aedeagus in lateral view almost of even width (Fig. 1C)..... Platynectes maizuqii sp. nov. - Median lobe of aedeagus in lateral view slightly broadened subapically (Fig. 7H)... Platynectes nanlingensis Šťastný, 2003 10 Size larger (TL: 5.9–6.1 mm); median lobe of aedeagus abruptly narrowing from subapical part to apex (Fig. 7F).................................................................................... Platynectes major Nilsson, 1998 - Size smaller (TL: 5.2–5.8 mm); median lobe of aedeagus not abruptly narrowing from subapical part to apex........... 11 11 Elytral longitudinal vittae not reduced basally (Fig. 2C), or indistinct basally (Fig. 2D), or even vanishing on basal third (Fig. 3A); apex of median lobe of aedeagus more pointed (Figs 6E–H)................... Platynectes dissimilis (Sharp, 1873) - Elytral longitudinal vittae not reduced basally (Figs 3B–C); apex of median lobe of aedeagus less pointed (Figs 6J–N)............................................................................ Platynectes gemellatus Šťastný, 2003, Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on pages 417-418, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121.","Sato, M. (1982) Two new Platynectes species from the Ryukyus and Formosa (Coleoptera, Dytiscidae). Special Issue in Memory of Retired Emeritus Professor Michio Chujo, 1982, 1 - 4.","Hajek, J., Alarie, Y., Stastny, J. & Vondracek, D. (2019) The first hygropetric Platynectes and its larva from eastern China (Coleoptera: Dytiscidae). Acta Entomologica Musei Nationalis Pragae, 59 (1), 217 - 228. https: // doi. org / 10.2478 / aemnp- 2019 - 0019","Sharp, D. (1873) The water beetles of Japan. The Transactions of the Entomological Society of London, 1873, 45 - 67. https: // doi. org / 10.1111 / j. 1365 - 2311.1873. tb 00636. x"]}

Platynectes mazzoldii Šťastný, 2003 (Figs 4D, 12A) Platynectes mazzoldii Šťastný, 2003: 240 (orig. descr.). Type locality. “ Thailand, Phu Hin Rongkla National Park, Huai Khamunoi ”. Type material. Holotype ♂, deposited in NHMW. Material examined. CHINA: Yunnan: 1 ♀, “ China: Yünnan, Xishuangbanna ca. 15 km NW Menglun 5.11.1999, ca. 700–800 m leg. Jäch, et al. (CWBS 354)” (NHMW). Notes. Habitus is given in Fig. 4D. Collection details. Found in primary forest streams and pools near waterfalls at altitudes ranging from 700 to 1250 m a.s.l. (Šťastný 2003). Distribution. Southern China (Yunnan, Xishuangbanna) (Fig. 12A). Notes. This species was reported from China based on only a single female specimen from Xishuangbanna, Yunnan (CWBS 354) by Šťastný (2003). This female was studied in great detail by one of us (J. Šťastný) and because it was identical in all characters with specimens from the type series it was identified as P. mazzoldii. It was not included in the type series (Šťastný 2003) because it was found about 500 km from the type locality of P. mazzoldii. There is currently a gap in the known distribution, but it is likely that it may occur from Thailand to southern China. The occurrence and distribution of this species in China need to be confirmed by further records., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 410, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259."]}

Platynectes dissimilis (Sharp, 1873) (Figs 2C–D, 3A, 6E–I, 8B–C, 10B) Agabus dissimilis Sharp, 1873: 50 (orig. descr.). Platynectes dissimilis (Sharp, 1873): Sharp 1882: 543 (n. comb.), Régimbart 1899: 288 (descr.), Guéorguiev 1972: 46 (descr.), Brancucci 1979: 202 (fauna), Satô 1982: 2 (syntype illustrated), Nilsson 1995: 56 (fauna), Šťastný 2003: 231 (descr.). Platynectes dissimilis dissimilis (Sharp, 1873): Nilsson 1998: 111 (descr.). Type locality. “ Japan ” (possibly mislabelled as never confirmed to occur in Japan). Type material. Syntype, deposited in BMNH. Material examined. CHINA: Guangdong: 4 ♂, 1 ♀, Zhaoqing, Dinghu, 19.vi.1958, C. Li leg. (SYSU); 7 ♂, 12 ♀, Dinghushan Mt., 23.vii.1964, T. Peng leg. (SYSU); 4 ♂, 4 ♀, Danxiashan Mt., 23.v.2008, F. Jia leg. (SYSU); 3 ♂, 4 ♀, Danxiashan Mt., Zhanglaofeng, 10.vi.2011, F. Jia leg. (SYSU); 1 ♀, Danxiashan Mt., Yangyuanshan, 10.vi.2011, F. Jia leg. (SYSU); 7 ♂, 11 ♀, Danxiashan Mt., Jinshi, puddle under rock wall, 11.vi.2011, F. Jia leg. (SYSU); 1 ♂, 1 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Feishuitan, 23.1754N, 112.5415E, 100 m, 2.iv.2021, Z. Jiang leg. (SYSU); 4 ♂, 5 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Feiqianqiao, 23.1748N, 112.5385E, 195 m, 3.iv.2021, Z. Jiang leg. (SYSU); 2 ♂, 2 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Dizhi management station, 23.1609N, 112.5323E, 90 m, 11.vii.2021, Z. Jiang, Z. Mai & Z. Liang leg. (SYSU); 2 ♂, 1 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Qingyunsi management station, 23.1736N, 112.5361E, 250 m, 12.vii.2021, Z. Jiang, Z. Mai & Z. Liang leg. (SYSU); 1 ♂, Zhaoqing, Dinghu distr., Dinghushan Mt., Qingyunsi management station, 23.1732N, 112.5354E, 260 m, 17.x.2021, Z. Jiang, Z. Mai & W. Xie leg. (SYSU); 3 ♂, 2 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Feiqianqiao-Qingyunsi, 23.1748N, 112.5385E, 195 m, 15.iii.2022, Z. Jiang & Z. Mai leg. (SYSU); 2 ♂, Zhaoqing, Dinghu distr., Dinghushan Mt., Qingyunsi management station, 23.1732N, 112.5354E, 260 m, 15.iii.2022, Z. Jiang & Z. Mai leg. (SYSU); 1 ♀, Zhaoqing, Dinghu distr., Dinghushan Mt., Tingquan Stone Carving, 23.1730N, 112.5434E, 60 m, 15.iii.2022, Z. Jiang & Z. Mai leg. (SYSU); Guangxi: 3 ♂, 5 ♀, Guilin, Longsheng County, Huaping Nature Reserve, 25.6239N, 109.9196E, 820 m, 22.viii.2020, day, Z. Jiang leg. (SYSU); 1 ♂, Guilin, Ziyuan County, Maoershan Mt., Huilong Tmple, 25.9125N, 110.4656E, 1560 m, 30.viii.2020, day, Z. Jiang leg. (SYSU); 7 ♂, 3 ♀, Guilin, Xingan County, Maoershan Mt., Huilong Tmple, 25°54′27″N, 110°28′3″E, 1070 m, 2.ix.2020, Z. Yang leg. (SYSU); Hunan: 3 ♂, 1 ♀, Yongzhou, Jiangyong County, Dupangling, Shangmuyuan, 25.3850N, 111.2932E, 320 m, 2.ix.2020, night & light trap, Z. Jiang leg. (SYSU); 3 ♂, Yiyang, Anhua County, Meicheng Town, Yunhe Village, 28.ii.2022, H. Mao leg. (SYSU); Jiangxi: 3 ♂, 3 ♀, Sanqingshan Mt., 15.viii.2006, F. Jia & H. Chen leg. (SYSU); 4 ♂, 8 ♀, Jinggangshan Mt., Dabali, 28. iv.2011, S. Zhao leg. (SYSU); Shaanxi: 1 ♂, 1 ♀, Huashan Mt., 24.viii.1984, Z. Huang leg. (SYSU); Zhejiang: 1 ♂, Quzhou, Qujiang distr., Caojiang Line (near Mingguo Temple), 29.1725N, 118.9054E, 240 m, 14.iii.2020, Z. Jiang leg. (SYSU); 7 ♂, 4 ♀, Quzhou, Jiangshan, Jinjia, 28.8734N, 118.6985E, 180 m, 20.iv.2020, Z. Jiang leg. (SYSU); 5 ♂, 6 ♀, Quzhou, Qujiang distr., Chacao, 29.2158N, 118.8261E, 455 m, 29.iv.2020, Z. Jiang leg. (SYSU); 3 ♂, 10 ♀, Quzhou, Qujiang distr., Liuchun Lake, Taoyuanjian, 28.7425N, 119.0389E, 780 m, 3.v.2020, Z. Jiang & X. Ye leg. (SYSU); 4 ♂, 4 ♀, Quzhou, Changshan County, Tianpu Village, 29.0727N, 118.6930E, 760 m, 24.vi.2020, Z. Jiang & X. Ye leg. (SYSU); 1 ♂, 1 ♀, Quzhou, Kaihua County, Gutianshan Nature Reserve, 29.2499N, 118.1402E, 695 m, 20.ii.2021, Z. Jiang & X. Ye leg. (SYSU); 2 ♂, 1 ♀, Quzhou, Qujiang distr., Yaowangshan Mt., Shennong Waterfall, 28.7632N, 118.9731E, 340 m, 24.viii.2021, Z. Jiang & X. Ye leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 2C–D, 3A and 6E–I. Collection details. In Zhejiang, the specimens were collected together with P. gemellatus among decaying leaves in a stream within the Gutianshan Nature Reserve (Fig. 8B) and in a puddle at the bottom of a rock wall covered with a film of seeping water, near Tianpu Village (Fig. 8C). Distribution. Central and southeastern China (Anhui, Fujian, Guangdong, Guizhou, Guangxi, Hunan, Jiangxi, Shaanxi, Shanxi, Zhejiang) (Fig. 10B). First record from Guangxi Zhuang Autonomous Region. Notes. Platynectes dissimilis exhibits highly variable elytral pattern. Examined specimens of P. dissimilis from Zhejiang and Sanqingshan Mt. (Jiangxi) had the elytral yellow vittae absent from the basal third of the elytra (Fig. 3A), two specimens from Shaanxi and a single specimen from Anhua County (Hunan) had the elytral yellow vittae indistinct only basally (Fig. 2D), whereas other specimens examined from south China were fully coloured (Fig. 2C). Since specimens we checked from southern areas (Guangdong, Guangxi and south Hunan) are more fully coloured, this variation might be related to temperature., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 407, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Sharp, D. (1873) The water beetles of Japan. The Transactions of the Entomological Society of London, 1873, 45 - 67. https: // doi. org / 10.1111 / j. 1365 - 2311.1873. tb 00636. x","Sharp, D. (1882) On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Dublin Society, Series 2, 2, 179 - 1003, pls. 7 - 18. https: // doi. org / 10.5962 / bhl. title. 9530","Regimbart, M. (1899) Revision des Dytiscidae de la region Indo-Sino-Malaise. Annales de la Societe Entomologique de France, 68, 186 - 367.","Gueorguiev, V. B. (1972) Notes sur les Agabini (Coleoptera, Dytiscidae). II. Revision des genres Platynectes Regimbart et Colymbinectes Falk. Izvestija na Zoologitjeskija Institut s Musei Sofia, 34, 33 - 62.","Brancucci, M. (1979) Dytiscidae aus dem Himalaja (Col.). Entomologica Basiliensia, 4, 193 - 212.","Sato, M. (1982) Two new Platynectes species from the Ryukyus and Formosa (Coleoptera, Dytiscidae). Special Issue in Memory of Retired Emeritus Professor Michio Chujo, 1982, 1 - 4.","Nilsson, A. N. (1995) Noteridae and Dytiscidae: Annotated check list of the Noteridae and Dytiscidae of China (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume I. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 35 - 96.","Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121."]}

Platynectes hainanensis Nilsson, 1998 (Figs 3D, 7A–B, 9A, 11B) Platynectes hainanensis Nilsson, 1998: 110 (orig. descr.); Šťastný 2003: 246 (notes). Type locality. “ China, Hainan, 30km E Maoyang, Wuzhi Shan Resort ”, ca. 18.9092N, 109.6776E, 700–800 m. Type material. Holotype ♂, deposited in IAECAS. Material examined. CHINA: Hainan: 1 ♀, Jianfengling Mt. (Five), 25.vi.1981, light trap, H. Rao leg. (SYSU); 5 ♂, 4 ♀, Limushan Mt., Limu Temple, 5.v.2011, S. Zhao leg. (SYSU); 6 ♂, 3 ♀, main peak of Limushan Mt., 6.v.2011, S. Zhao leg. (SYSU); 2 ♂, third and fifth divisions of Jianfengling Mt., 9.v.2011, S. Zhao leg. (SYSU); 6 ♂, 2 ♀, Changjiang County, Bawangling Mt., Bawang Stone Sea, 19.0814N, 109.1233E, 550 m, 22.v.2022, Z. Jiang leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 3D and 7A–B. Collection details. Platynectes hainanensis was collected at stream bottoms among decaying leaves in Limushan Mt. (Hainan) (Fig. 9A). Distribution. Known only from the Hainan Province, China (Fig. 11B)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 409, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121.","Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259."]}

Platynectes gemellatus Šťastný, 2003 (Figs 3B–C, 6J–O, 8B, D, 11A) Platynectes gemellatus Šťastný, 2003: 235 (orig. descr.); Liu 2020: 32 (descr.). Type locality. “ China, Hong Kong ”. Type material. Holotype ♂, deposited in NHMW. Material examined. CHINA: Guangdong: 1 ♂, 2 ♀, Fengkai, Heishiding, 10.iv.1985, W. Wu leg. (SYSU); 3 ♀, Fengkai, Heishiding, 2.v.2011, F. Jia leg. (SYSU); 2 ♀, Lian County, Dadongshan Mt., 7.vii.1995, F. Jia & Y. Liu leg. (SYSU); 1 ♂, 4 ♀, Lian County, Dadongshan Mt., 22.vi.2004, X. Fang leg. (SYSU); 1 ♂, Nanling, Dadongshan Mt., vi.2004, F. Jia leg. (SYSU); 2 ♂, 1 ♀, Lian County, Dadongshan Mt., 6.vii.2008, F. Jia leg. (SYSU); 2 ♀, Nanling, Dadongshan Mt., 23-27.vi.2009, F. Jia leg. (SYSU); 3 ♂, Shaoguan, Chebaling, Fanchifeng, 24°42′9″N, 114°11′10″E, 485 m, 20.viii.2020, Z. Yang leg. (SYSU); 4 ♂, 5 ♀, Shaoguan, Chebaling Nature Reserve, 24°43′6″N, 114°15′8″E, 450 m, 21.viii.2020, Z. Yang leg. (SYSU); 2 ♂, 2 ♀, Huizhou, Longmen County, Nankunshan Reserve, 23.6349N, 113.8409E, 550 m, 23.iii.2021, Z. Jiang leg. (SYSU); 5 ♂, 3 ♀, Huizhou, Longmen County, Nankunshan Mt., Gaoshanbieshu, 23.6249N, 113.8709E, 640 m, 7-9.vii.2021, Z. Jiang, Z. Mai & Z. Liang leg. (SYSU); 3 ♂, 3 ♀, Guangzhou, Conghua distr., Liuxihe, Wuzhishan Scenic Spot, 23.7339N, 113.8075E, 295 m, 26.iii.2021, Z. Jiang leg. (SYSU); 3 ♂, 4 ♀, Ruyuan, Nanling, mid-mountain protection station, 1000m, 23.viii.2010, S. Zhao leg. (SYSU); 3 ♂, 1 ♀, Shaoguan, Ruyuan County, Nanling, Ruyang Management Station, 24.9281N, 113.0177E, 980 m, 2.xi.2021, Z. Mai leg. (SYSU); 1 ♂, 1 ♀, Shaoguan, Ruyuan County, Nanling, Laopengyidui, 24.9304N, 113.0131E, 1050 m, 3.xi.2021, Z. Mai leg. (SYSU); 3 ♂, Shaoguan, Ruyuan County, Nanling, 24.9252N, 112.9800E, 1600 m, 4.xi.2021, Z. Mai leg. (SYSU); Hongkong: 1 ♂, Dabujiao (Hexi), 22°25.697′N, 114°10.834′E, 145 m, 10.iv.2014, F. Jia, W. Xie & J. Chen leg. (SYSU); 1 ♂, 1 ♀, Rongshuao, 22°32.646′N, 114°14.926′E, 10 m, 11.iv.2014, F. Jia, W. Xie & J. Chen leg. (SYSU); 2 ♂, 1 ♀, Fengkeng, 22°31.695′N, 114°13.450′E, 13 m, 9.vi.2014, F. Jia, W. Xie & J. Chen leg. (SYSU); 1 ♂, Rongshuao, 22°25.641′N, 114°17.410′E, 10 m, 11.vi.2014, F. Jia, W. Xie & J. Chen leg. (SYSU); 1 ♂, Datan (Lejuyuan), 22°15.513′N, 114°12.163′E, 240 m, 13.vi.2014, F. Jia, Y. Li & J. Chen leg. (SYSU); 1 ♀, Shaluodong, 22°28.555′N, 114°10.909′E, 185m, light trap, F. Jia, W. Xie & Alex leg. (SYSU); Hunan: 3 ♂, 4 ♀, Shaoyang, Chengbu County, Baimaoping Town, Xiatang Road, 26.2643N, 110.3585E, 530 m, 23.viii.2020, night & light trap, Z. Jiang leg. (SYSU); 1 ♀, Shaoyang, Chengbu County, Jinzishan forest farm, Yaorenping, 26.2524N, 110.4976E, 825 m, 25.viii.2020, day, Z. Jiang leg. (SYSU); 3 ♂, 1 ♀, Shaoyang, Chengbu Miao Autonomous County, Lanrong Township, Jintongshan Mt., 26°17′51″N, 110°28′58″E, 1095 m, 8.ix.2020, Z. Yang leg. (SYSU); 1 ♀, Shaoyang, Chengbu Miao Autonomous County, Lanrong Township, Jintongshan Mt., 26°14′64″N, 110°22′25″E, 565 m, 8.ix.2020, light trap, Z. Yang leg. (SYSU); 3 ♀, Chenzhou, Mangshan Mt., Jiangjunzhai, 24°57′1″N, 112°55′58″E, 1260 m, 27.viii.2020, Z. Yang leg. (SYSU); 1 ♂, Chenzhou, Yizhang County, Mangshan Mt., 24.9457N, 112.9824E, 1480 m, 5.ix.2020, Z. Ma leg. (SYSU); Jiangxi: 7 ♂, 3 ♀, Jinggangshan Mt., Jingzhushan Scenic Area, 4.x.2010, S. Zhao leg. (SYSU); 3 ♂, 1 ♀, Jinggangshan Mt., Shuangxikou, 5.x.2010, S. Zhao leg. (SYSU); 2 ♂, 1 ♀, Jinggangshan Mt., Shuangxikou, 24.iv.2011, S. Zhao leg. (SYSU); 1 ♀, Jinggangshan Mt., Huyangta, 28.iv.2011, S. Zhao leg. (SYSU); 11 ♂, 8 ♀, main peak of Jinggangshan Mt., 605 m, 29.iv.2011, S. Zhao leg. (SYSU); 1 ♂, Jinggangshan Mt., Xiazhuang, 29.iv.2011, S. Zhao leg. (SYSU); 1 ♀, Jinggangshan Mt., 1.iv.2011, Y. Li leg. (SYSU); 1 ♂, Jinggangshan Mt., Xiangzhou, 28.v.2011, L. Yang leg. (SYSU); 16 ♂, 8 ♀, Ganzhou, Jiulianshan Mt., Xiagongtang, 24°32′28″N, 114°27′32″E, 525 m, 18.viii.2020, Z. Yang leg. (SYSU); Macao: 1 ♂, Luhuan, Zhugutang, 27.iii.2014, W. Xie leg. (SYSU); 5 ♂, 6 ♀, Luhuan, Dieshitang, 27.iii.2014, F. Jia, W. Xie & J. Wang leg. (SYSU); Zhejiang: 1 ♂, Quzhou, Kaihua County, Gutianshan Nature Reserve, 29.2499N, 118.1402E, 695 m, 20.ii.2021, Z. Jiang & X. Ye leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 3B–C and 6J–O. Collection details. The specimen from Gutianshan Nature Reserve was collected together with P. dissimilis among decaying leaves in a stream (Fig. 8B); in Liuxihe, specimens were also collected in small shallow puddles on a mountain dirty road (Fig. 8D). Distribution. Southern and eastern China (Fujian, Guangdong, Guangxi, Guizhou, Hunan, Hongkong, Jiangxi, Macao, Taiwan, Zhejiang) (Fig. 11A). First record from Hunan and Zhejiang provinces. Notes. During field collections by the senior author in Gutianshan Mt. (Zhejiang), it was observed that P. gemellatus and P. dissimilis were living together in the same place of the same stream. However, P. gemellatus is much rarer than P. dissimilis here, probably because drifting through the water facilitates dispersal. At other localities both species probably do not occur in the same habitat. These two species may have different ecological requirements, but this needs to be confirmed by more observations in the future. Specimens of both species from Gutianshan Mt. are easy to distinguish, in P. gemellatus with elytral yellow vittae not reduced basally (Fig. 3C) and apex of median lobe of aedeagus less pointed (Fig. 6M), and in P. dissimilis with elytral yellow vittae vanishing on basal third of elytra (Fig. 3A) and apex of median lobe of aedeagus more pointed (Fig. 6H). However, when the full spectrum of the colour range is considered, P. gemellatus can closely resemble P. dissimilis (Fig. 2C). Except for the shape of the median lobe of aedeagus, other characters such as body size and aspect of longitudinal grooves on male abdominal ventrite VI are not stable and cannot be used reliably for identification. Even the shape of the median lobe of aedeagus of specimens of these two species from different areas is somewhat variable (Figs 6E–H, 6J–N), and there are intermediate forms difficult to distinguish. In addition, fully coloured specimens of P. dissimilis may also occur syntopically with P. gemellatus as that in Gutianshan Mt. stated above, which increases the difficulty., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on pages 408-409, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Liu, H. C. (2020) Review of the Genus Platynectes Straneo [sic!], 1939 (Coleoptera: Dytiscidae) from Taiwan. Taiwanese Journal of Entomological Studies, 5 (2), 31 - 35."]}

Platynectes davidorum Hájek, Alarie, Šťastný & Vondráček, 2019 (Figs 2B, 6C–D, 8A, 10A) Platynectes davidorum Hájek, Alarie, Šťastný & Vondráček, 2019: 221 (orig. descr.). Type locality. “ China, Fujian Province, Nanping Prefecture, Wuyishan Mts., Tongmu –Sangang vill.”, ca. 27°45.0′N, 117°40.7′E, 720 m. Type material. Holotype ♂, deposited in IZCAS. Material studied. CHINA: Jiangxi: 1 ♂, Shangrao, Sanqingshan Mt., 15-20.iv.2007, F. Jia leg. (SYSU); Zhejiang: 5 ♂, 10 ♀, Quzhou, Qujiang distr., Yaowangshan Mt., Shennong Waterfall, 28.7632N, 118.9731E, 340 m, 24.viii.2021, Z. Jiang & X. Ye leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 2B and 6C–D. Collection details. In Yaowangshan Mt. (Zhejiang), Platynectes davidorum was collected during the day under mosses on wet rock, and at night in crevice or surface of rock covered with water film near waterfall (Fig. 8A). Distribution. Eastern China (Fujian, Jiangxi, Zhejiang) (Fig. 10A). First record from Jiangxi province. Notes. Platynectes davidorum seems to be strictly hygropetric, all specimens examined and also the type material (Hájek et al. 2019) were found in water films on rock surface. The strongly convex body and short appendages of the adults are likely adaptive features associated with this hygropetric lifestyle (Hájek et al. 2019). Besides this, another hygropetric species Hydrotrupes chinensis Nilsson, 2003, collected together with P. davidorum in Yaowangshan Mt. (Zhejiang), also displays a strongly convex body and short appendages, and furthermore absence of natatory setae on legs. These characters reflect adaptation to life on wet rock walls and limited ability to swim. Although Hydrotrupes palpalis Sharp, 1882 from North America has been shown capable of swimming (Hering 1998), individuals of this species often stay on rock surface within water films (Larson et al. 2000). The presence of natatory setae on the legs of P. davidorum may suggest that this species retains an ability to swim, as has been shown for the well-known North American hygropetric Hydrotrupes palpalis., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 406, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Hajek, J., Alarie, Y., Stastny, J. & Vondracek, D. (2019) The first hygropetric Platynectes and its larva from eastern China (Coleoptera: Dytiscidae). Acta Entomologica Musei Nationalis Pragae, 59 (1), 217 - 228. https: // doi. org / 10.2478 / aemnp- 2019 - 0019","Nilsson, A. N. (2003) A new species of Hydrotrupes Sharp from China, an example of Pacific intercontinental disjunction. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 279 - 284.","Sharp, D. (1882) On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Dublin Society, Series 2, 2, 179 - 1003, pls. 7 - 18. https: // doi. org / 10.5962 / bhl. title. 9530","Hering, D. (1998) Riparian beetles (Coleoptera) along a small stream in the Oregon Coast Range and their interactions with the aquatic environment. The Coleopterists Bulletin, 52, 161 - 170.","Larson, D. J., Alarie, Y. & Roughley, R. E. (2000) Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska. NRC Research Press, Ottawa, 982 pp."]}

Platynectes maizuqii sp. nov. (Figs 1A, C–D, 12A) Type locality. China, Guangdong Province, Shaoguan, Renhua County, Danxiashan Mt., ca. 25.0347N, 113.7407E, 100 m. Type material. Holotype ♂ (SYSU), labelled: “ ŨAE ḂOiẌffiḩẇh / BDƜ / 25.0347N,113.7407E / 98.0 m, 20.ix.2021 / RDZƛ [p] // CHINA: Guangdong Province / Shaoguan, Renhua County / Danxiashan Mt. / 25.0347N, 113.7407E / 98.0 m, 20.ix.2021 / Zuqi Mai leg. [p] // HOLOTYPE / PLATYNECTES / maizuqii sp. nov. / Jiang, Jia & Šťastný det. 2022 [red label, p]”. Paratypes: 1 ♂, same label data as holotype (SYSU); 2 ♀, labelled: “ ŨAEBDƜ / 2008.5.23 / NJΦλ:AEṂÄ [p] // CHINA: Guangdong Province / Danxiashan Mt. / 23.v.2008 / Fenglong Jia leg. [p]” (SYSU). All paratypes with the respective red printed label. Description of holotype. Habitus (Fig. 1A) oblong-oval, with continuous outline, broadest before middle of elytral length, moderately convex. Dorsal surface slightly matt due to distinct reticulation. Colouration. Head yellow, with black triangular spots on frons between eyes; pronotum black with anterior angles and lateral margins yellow, anterior margin and transverse medial band reddish-brown; elytra black with yellow transverse basal fascia and eight longitudinal vittae, sublaterally behind middle of elytral length and near apex with irregular yellow spots; appendages reddish-brown; ventral side black with reddish-brown spot on each side of abdominal ventrites II–IV. Head. Moderately broad, width ca. 0.6× that of pronotum. Anterior margin of clypeus semicircular, with pair of sublateral foveae. Antenna with antennomeres long and slender. Eyes emarginate anterolaterally. Punctation double; several coarse setigerous punctures present in fronto-clypeal grooves and in depressions along inner margin of eyes; fine punctures distributed sparsely and irregularly on head surface, mainly at intersections of meshes. Reticulation deeply impressed consisting of heterogeneous, somewhat elongate, polygonal meshes; most meshes closed, usually with several micropunctures inside. Pronotum. Transverse (width/length ratio = 3.5), broadest between posterior angles. Sides moderately curved, with distinct bead. Anterior margin nearly straight, posterior margin slightly sinuate. Punctation double, similar to that of head; rows of coarse setigerous punctures present along anterior margin and lateral parts of basal margin; fine punctures distributed irregularly on pronotal surface, mainly at intersections of reticulation. Reticulation similar to that of head, on disc meshes larger and less impressed, sometimes not closed, near sides becoming much smaller and more deeply impressed. Centre of disc with small indistinct longitudinal furrow. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra moderately curved. Transverse yellow fascia present at base of elytra, interrupted only sublaterally. Eight yellow longitudinal vittae present on each elytron: vitta 1 almost continuous, vittae 2–7 formed by series of dots, vitta 8 interrupted medially, vitta 5 bifurcate anteriorly; vittae 1–5 and 8 beginning from transverse basal fascia and ending at apex, vittae 6 and 7 beginning slightly behind transverse basal fascia and ending at apex. Punctation double; coarse setigerous punctures present along vittae 1, 3, 5, 7 and lateral margins of elytra; fine punctures distributed irregularly over elytral surface, mainly at intersections of reticulation. Reticulation well impressed, similar to that of head and pronotum, meshes usually with several micropunctures inside, sometimes not closed. Legs. Meso- and metafemora with tuft of spiniform setae along ventral margin of anteroapical angle. Pro- and mesotibia broadened, club shaped, densely punctured with spinigerous punctures over ventral surface. Metatibia with two lines of coarse spinigerous punctures on ventral surface. Pro- and mesotarsomeres 1–3 moderately broadened, with adhesive setae on ventral side; claws simple. Metatarsal claws subequal; anterior claw slightly shorter than posterior one. Surface of legs with distinct reticulation consisting of elongate meshes. Ventral side. Anterior margin of prosternum sinuate, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, with distinct lateral bead in basal half, apex pointed; surface with irregular sparse double punctation. Medial part of metaventrite without microsculpture, shiny, with sparse fine punctation; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender, reaching lateral margins. Metacoxal lines distinct, well impressed, subparallel anteriorly, divergent posteriorly. Metacoxal plates covered with shallow transverse wrinkles; reticulation consisting of polygonal meshes, punctation consisting of sparse fine punctures. Conjoint posterior margin of metacoxal processes slightly concave. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrite I, oblique on ventrite II and transverse on ventrites III–V; ventrites III–V additionally with numerous fine transverse wrinkles medially. Punctation double; ventrites III–V with setigerous punctures arranged sparsely in transverse line in medial part and with one coarser setigerous puncture presents in middle; fine punctures distributed sparsely and irregularly on ventrite surface. Abdominal ventrite VI with sublateral rugose area comprising nearly 10 deep longitudinal grooves on each side; reticulation present only baso-laterally; punctation double, coarse setigerous punctures present along posterior margin, fine punctures distributed densely on middle part. Male genitalia. Median lobe of aedeagus in lateral view strongly curved; with distinct setae subapically along both ventral and dorsal margins; basal piece with distinct protuberance subapically on dorsal side; apical region moderately elongate, apex rounded (Fig. 1C). Parameres slender, with dense setae dorsally, with distinct subbasal tooth on ventral side (Fig. 1D). Female. Identical to male in habitus. Meshes of dorsal surface reticulation more deeply impressed and longitudinally stretched, reticulation postero-laterally to eyes densely consists of elongate closed meshes, surface appearing more matt. Abdominal ventrite VI without deep longitudinal grooves sublaterally. Pro- and mesotibia less broadened; pro- and mesotarsomeres not broadened, without adhesive setae ventrally. Variability. Sublaterally behind middle of elytral length sometimes without irregular yellow spots. Measurements. TL: 6.3–6.5 mm (mean value: 6.4 ± 0.1 mm); holotype: 6.4 mm. TL-h: 5.7–5.9 mm (mean value: 5.8 ± 0.1 mm); holotype: 5.8 mm. MW: 3.8–4.0 mm (mean value: 3.9 ± 0.1 mm); holotype: 3.8 mm. Differential diagnosis. The new species is similar to P. nanlingensis Šťastný. Some specimens of P. maizuqii sp. nov. with irregular yellow spots sublaterally behind middle of elytral length, but this is not stable. The two species can be reliably distinguished by the shape of the median lobe: apical region in lateral view almost of even width in P. maizuqii sp. nov., but slightly broadened in P. nanlingensis. Collection details. The two male specimens were collected among crevices between stones in a rainwater ditch alongside a mountain road. Etymology. The species is dedicated to its collector, Zu-qi Mai (SYSU), a specialist of water scavenger beetles (Hydrophilidae). The species name is a noun in the genitive singular. Distribution. So far known only from the type locality in Danxiashan Mt., northern Guangdong, China (Fig. 12A).

Platynectes major Nilsson, 1998 (Figs 4C, 7F–G, 9C, 12A) Platynectes dissimilis major Nilsson, 1998: 114 (orig. descr.). Platynectes major Nilsson, 1998: Šťastný 2003: 233 (n. stat.). Type locality. “S Vietnam, N Dalat, Lang Bian”. Type material. Holotype ♂, deposited in NHMW. Material examined. CHINA: Yunnan: 2 ♂, 4 ♀, Lvchun County, ditches and terraces by the roadside, 22.8856N, 102.3264E, 1440 m, 1.v.2021, Z. Jiang, Z. Yang & Z. Mai leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 4C and 7F–G. Collection details. The specimens from Lvchun were collected in ditches by the roadside (Fig. 9C). Distribution. Southern China (Yunnan) (Fig. 12A)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on page 410, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121.","Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259."]}

Platynectes rihai Šťastný, 2003 (Figs 5B, 7J–K, 12B) Platynectes rihai Šťastný, 2003: 243 (orig. descr.). Type locality. “ China, Shandong Province, Tai’an Prefecture, Tai Shan Nature Reserve ”, ca. 36.2634N, 117.0822E, 350 m. Type material. Holotype ♂, deposited in IAECAS. Material studied. CHINA: Shandong: 4 ♂, 11 ♀, Taishan Mt., foot of Tianzhufeng, 15.vii.2008, Y. Liu leg. (SYSU). Notes. Habitus and male genitalia are given in Figs 5B and 7J–K. Collection details. In Tai Shan Nature Reserve, specimens were collected in a small, slowly flowing stream and also in ground water pools among big rocks (Nilsson 1998; Šťastný 2003). Distribution. Known only from Taishan Mt., Shandong Province, China (Fig. 12B)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), pp. 401-425 in Zootaxa 5227 (4) on pages 415-417, DOI: 10.11646/zootaxa.5227.4.1, http://zenodo.org/record/7518878, {"references":["Stastny, J. (2003) Review of Platynectes subgen. Gueorguievtes Vazirani from Southeast Asia. In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. III. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 217 - 259.","Nilsson, A. N. (1998) Dytiscidae: V. The genus Platynectes Regimbart in China, with a revision of the dissimilis - complex (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Volume II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 107 - 121."]}

Copelatus zimmermanni Gschwendtner, 1934 (Figs 27, 69–70) Copelatus zimmermanni Gschwendtner in Zimmermann, 1934: 143. Type locality. “ China (Hangchow)” [China, Zhejiang Province, Hangzhou, ca. 30°16′N 120°09′E]. Type material. Holotype ♀, originally deposited in Yenching University, Beijing, China; destroyed during fire in 1980’. Material examined. CHINA: Guangdong: 3 ♂, 4 ♀, Danxiashan Mts., 23.v.2008, F. Jia leg. (SYSU); 9 spec., 30 km NE Shaoguan, Duanshi vill., Danxiashan NP, 25°02.7′N 113°43.8′E, 125 m, pool, 4.-5.v.2011, J. Hájek leg. (NMPC); 1 ♂, Danxiashan Mts., Yangyuanshan, 10.vi.2011, F. Jia leg. (SYSU). Diagnosis. Medium sized (TL: 5.4–5.7 mm), oblong-oval species; dorsal surface distinctly convex. Head reddish, with dark band along eyes and infuscation on frons between eyes; pronotum reddish brown, laterally broadly testaceous; elytra brown, with very broad, irregularly shaped, transverse basal orange band. Pronotum with few short longitudinal strioles laterally. Each elytron with 11 superficially impressed discal striae: sutural stria usually strongly reduced to few short strioles, or almost absent in some specimens; all striae abbreviated posteriorly, striae 2, 3, 5, 7 and 9 ending in posterior fourth of elytral length, striae 4, 6, 8 and 11 reaching apical fourth of elytral length; striae 7 and 9 often fragmented to strioles throughout their length (Fig. 27). Median lobe broad, club-shaped, with two protuberances on dorsal side, sinuate on ventral margin; apex beak-shaped (Fig. 69). Paramere slender ‘C’-shaped; apex slender; apical lobe long, club-shaped (Fig 70). Female similar to male; strioles on pronotum more numerous, elytral striae more impressed. Collection details. The specimens from Danxiashan were collected in shallow open pool with sparse littoral vegetation, and in a pool on a stream (Fig. 78). Distribution. A species described from Zhejiang (China), and subsequently recorded also from Japan and Korea (Satô 1985, Park et al. 2008). First record from Guangdong province (Fig. 83)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 275-276, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Zimmermann, A. (1934) Monographie der palaarktischen Dytisciden. V. Colymbetinae (1. Teil). (Copelatini, Agabini: Gattung Gaurodytes Thoms.). Koleopterologische Rundschau, 20, 138 - 214.","Sato, M. (1985) The genus Copelatus of Japan (Coleoptera: Dytiscidae). Transactions of the Shikoku Entomological Society, 17, 57 - 67.","Park, H. C., Lee, Y. B. & Lee, H. A. (2008) Taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea. Entomological Research, 38 (1), 73 - 76. https: // doi. org / 10.1111 / j. 1748 - 5967.2008.00134. x"]}

Copelatus weymarni J. Balfour-Browne, 1947 (Figs 25, 62–66) Copelatus weymarni J. Balfour-Browne, 1947: 440; Zeng 1989: 6 (Shanghai); Li 1992: 35 (Liaoning); Nilsson 1995: 42 (Hebei: Beidaihe). Type locality. “Manchuria: Djalantun” [China, Nei Mongol, Zalantun, ca. 48°00′N 122°44′E]. Type material. Holotype ♂, deposited in BMNH (not studied). Material examined. CHINA: Liaoning: 1 ♂, 92 km SE Benxi, 200 m, 29.ix.1994, Ji & Wang leg. (NHMW); Shanghai: 6 spec., Shanghai (IZCAS). Diagnosis. Medium sized (TL: 5.1–5.5 mm), oblong-oval species. Head reddish-brown, clypeus somewhat paler – testaceous; pronotum reddish-brown with broadly testaceous anterior margin and lateral sides; elytra dark brown, basal margin and especially lateral sides paler – testaceous. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: all striae beginning at base and ending close to apex, only stria 6 shorter and ending at apical fourth; submarginal stria long, beginning at about elytral mid-length (Fig. 25). Median lobe of aedeagus in lateral view sickle-shaped with apex slightly turned dorsally, with large irregular process on dorsal side near mid-length (Fig. 65). Parameres moderately broad, ‘C’-shaped; apex rather slender; apical lobe long, club-shaped (Fig. 66). Female similar to male, strioles on pronotum more numerous. Distribution. A species described from Inner Mongolia (not Heilongjiang, as stated by Nilsson 1995), and subsequently recorded also from Hebei, Shanghai and Liaoning in northeastern China (Zeng 1989, Li 1992, Nilsson 1995) (Fig. 83). In addition to China, C. weymarni occurs in the Far East of Russia, Japan and Korea (Satô 1985, Nilsson 1995, Park et al. 2008)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 274, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Balfour-Browne, J. (1947) The aquatic Coleoptera of Manchuria (Weymarn collection). The Annals and Magazine of Natural History, Eleventh Series, 13 (1946), 433 - 460. https: // doi. org / 10.1080 / 00222934608654567","Zeng, H. (1989) Classification of Dytiscidae (Insecta: Coleoptera) - A study of the collections of Dytiscidae from major museums in China. Unpublished PhD Thesis, Department of Biology, University of Sun Yat-sen University, Guangzhou, 152 pp. [in Chinese with English abstract]","Li, J. (1992) The Coleoptera Fauna of Northeast China. Jilin Education Publishing House, Jilin, 205 pp.","Nilsson, A. N. (1995) Noteridae and Dytiscidae: Annotated check list of the Noteridae and Dytiscidae of China (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 35 - 96.","Sato, M. (1985) The genus Copelatus of Japan (Coleoptera: Dytiscidae). Transactions of the Shikoku Entomological Society, 17, 57 - 67.","Park, H. C., Lee, Y. B. & Lee, H. A. (2008) Taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea. Entomological Research, 38 (1), 73 - 76. https: // doi. org / 10.1111 / j. 1748 - 5967.2008.00134. x"]}

Copelatus tenebrosus Régimbart, 1880 (Figs 22, 61–62) Copelatus tenebrosus Régimbart, 1880: 210. For full list of synonyms, see Nilsson & Hájek (2022a: 61); Zimmermann 1927: 32 (Yunnan); Feng 1933: 326 (Fujian: Amoy); Jäch & Easton 1998: 44 (Macao: Friendship Monument). Type locality. “Solok, district of Rawas and Soeroelangoen” [Indonesia, Sumatra Island]. Type material. Syntypes deposited in Naturalis Biodiversity Center [former Rijksmuseum van Natuurlijke Historie], Leiden, Netherlands (not studied). Material examined. CHINA: Guangdong: 3 ♂, 1 ♀, Zhuhai, Hengqin Island, 10.vii.2006, F. Jia leg. (SYSU); 3 ♂, Zhuhai, Qi’ao Island, 13.-15.vii.2005, Y. Jia leg. (SYSU). Macao: 1 ♂, Cotai Ecological Zone, 4.-5.iv.2013, F. Jia & W. Xie leg. (SYSU); 4 ♂, 3 ♀, Cotai Ecological Zone, 10.x.2020, F. Jia & W. Xie leg. (SYSU). Yunnan: 7 ♂, 8 ♀, Jinghong, xii.1984 (SYSU); 4 ♂, 7 ♀, Xishuangbanna Agricultural Science Institute, xii.1985 (SYSU); 1 ♂, 2 ♀, Xishuangbanna, xii.1985 (SYSU); 2 ♂, 3 ♀, Xishuangbanna, Jinghong, eastern city, 500m, 12.xi.1999, M. Jäch et al. leg. (NHMW, NMPC); 1 ♀, Mengla County, Shangyong Town, 2.viii.2007, L. Shi leg. (SYSU); 1 ♂, Mengla County, Shangyong Town, 1.-3.viii.2007, J. Li leg. (SYSU); 1 ♀, Mengla Nature Reserve, 4.-5.viii.2007, J. Li leg. (SYSU). Diagnosis. Smaller (TL: 4.0– 4.9 mm), oblong-oval species. Head dark brown, clypeus and anterior part of frons usually paler, reddish; pronotum dark brown, laterally broadly reddish, anterior and posterior margin sometimes reddish translucent; elytra dark brown to black, with paler, reddish brown sides laterally from stria 6. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: striae 1 and 5 beginning slightly posteriorly from base, stria 6 more distinctly so; even striae ending close to apex, odd striae usually shorter, ending more subapically; stria 6 shortest, ending at apical fourth; submarginal stria long, beginning at elytral mid-length and ending at apical fourth (Fig. 22). Median lobe of aedeagus in lateral view sickle-shaped, simple, regularly turned in apical half to obtusely pointed apex (Fig. 61). Parameres broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 62). Female identical to male. Collection details. Copelatus tenebrosus inhabits various kinds of stagnant water bodies, especially puddles and small pools with at least some vegetation; abundant in paddy fields; frequently attracted at light traps. Distribution. One of the most widespread Copelatus species, occurring in the Oriental and Australian Regions, from the Indian subcontinent to Australia (Sheth et al. 2018, Hendrich et al. 2019). Its northernmost distribution is confined to southern China (Fujian, Macao, Taiwan, Yunnan) and Ryukyus (Satô 1985, Nilsson 1995); first record from Guangdong (Fig. 83)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 272, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Regimbart, M. (1880) The new Dytiscidae and Gyrinidae collected during the recent scientific Sumatra-expedition. Notes from the Leyden Museum, 2, 209 - 216.","Nilsson, A. N. & Hajek, J. (2022 a) A World Catalogue of the family Dytiscidae, or the Diving Beetles (Coleoptera, Adephaga). Version 1. I. 2022. Distributed as a PDF file via Internet. Available from: http: // www. waterbeetles. eu (accessed 20 January 2022)","Zimmermann, A. (1927) Fauna sumatrensis. (Beitrag Nr. 45). Revision der Haliplidae et Dytiscidae von Sumatra. Supplementa Entomologica, Berlin Dahlem, 16, 1 - 44.","Feng, H. T. (1933) Aquatic insects of China. Article VIII. Additions and corrections to the catalogue of Chinese Dytiscidae. Peking Natural History Bulletin, 7 (1932 - 33), 323 - 333.","Jach, M. A. & Easton, E. R. (1998) Water beetles of Macao (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.) Water beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 43 - 50","Sheth, S. D., Ghate, H. V. & Hajek, J. (2018) Copelatus Erichson, 1832 from Maharashtra, India, with description of three new species and notes on other taxa of the genus (Coleoptera: Dytiscidae: Copelatinae). Zootaxa, 4459 (2), 235 - 260. https: // doi. org / 10.11646 / zootaxa. 4459.2.2","Hendrich, L., Shaverdo, H., Hajek, J. & Balke, M. (2019) Taxonomic revision of Australian Copelatus Erichson, 1832 (Coleoptera, Dytiscidae, Copelatinae). ZooKeys, 889, 81 - 152. https: // doi. org / 10.3897 / zookeys. 889.39090","Sato, M. (1985) The genus Copelatus of Japan (Coleoptera: Dytiscidae). Transactions of the Shikoku Entomological Society, 17, 57 - 67.","Nilsson, A. N. (1995) Noteridae and Dytiscidae: Annotated check list of the Noteridae and Dytiscidae of China (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 35 - 96."]}

Key to species (males predominantly) 1. Each elytron with five discal striae. Dark brown with reddish head and lateral sides of pronotum, elytra with broad orange transverse basal band, lateral sides and subapical spot (Fig. 16). Small (TL: 3.5–4.0 mm), parallel-sided species from central and eastern China, Korea and Japan........................................... C. parallelus Zimmermann, 1920 - Each elytron with six or more discal striae................................................................. 2 2. Each elytron with six discal striae........................................................................ 3 - Each elytron with more than six discal striae; even striae may be short (occupying only basal fourth of elytral length) or fragmented into several strioles (Fig. 5).................................................................. 22 3. Broader species. Median lobe of aedeagus near mid-length with distinct finger-like process on ventral side (Figs 49, 59)... 4 - Narrower species. Median lobe of aedeagus usually sickle-shaped, without distinct process on ventral side.............. 5 4. Smaller (TL: 4.3–5.3 mm), widely distributed Oriental species reaching southern China. Median lobe of aedeagus near midlength with small dent on dorsal side (Fig. 49). Brown blackish, elytra usually with thin basal orange transverse band (Figs 14–15). Females dimorphic........................................................... C. oblitus Sharp, 1882 - Larger (TL: 5.2–6.1 mm), widely distributed Oriental species reaching southern and eastern China. Median lobe of aedeagus near mid-length with broad spoon-like process on dorsal side (Fig. 59). Brown blackish, elytra usually with broad comb-like shaped basal orange transverse band and orange-brown sides laterally from elytral stria 3 (Fig. 21). Females similar to males ….................................................................. C. sociennus J. Balfour-Browne, 1952 5. Elytra yellow orangish with two irregular transverse blackish bands, one medially and one subapically (Fig. 28). Male unknown. Smaller (TL: 4.5–4.8 mm) species from Hongkong................................................ Copelatus sp. - Elytra brown to black, at most with paler lateral sides and transverse basal band................................... 6 6. Median lobe of aedeagus near mid-length with large irregular process on dorsal side (Fig. 65). Dark brown, head, lateral sides of pronotum, and base and lateral sides of elytra usually paler (Fig. 25). Larger (TL: 5.1–5.5 mm) species from northeastern China............................................................... C. weymarni J. Balfour-Browne, 1947 - Median lobe of aedeagus with dorsal side simple, continuous.................................................. 7 7. Elytra blackish with paler lateral sides, without pale transverse basal band (Fig. 22). Elytral striae 1, 5 and 6 beginning posteriorly to base. Median lobe of aedeagus sickle-shaped, simple; in apical half regularly curved and only slightly narrowed to apex (Fig. 61). Smaller (TL: 4.0– 4.9 mm), widely distributed species........................... C. tenebrosus Régimbart, 1880 - Elytra light to dark brown, often with pale transverse basal band. Elytral striae usually beginning at base. Larger (TL:> 4.5 mm) species............................................................................................. 8 8. Apical part of median lobe of aedeagus bisinuous (Figs 35, 45)................................................ 9 - Apical part of median lobe of aedeagus straight or sinuous................................................... 10 9. Median lobe of aedeagus in third quarter with a distinct shallow swelling on ventral side; apical fourth slender (Fig. 35). Brown, with lateral sides of pronotum, base and lateral sides of elytra indistinctly paler (Fig. 7). Larger (TL: 5.5 mm) species from northwestern Yunnan..................................................................... C. felicis sp. nov. - Median lobe of aedeagus without swelling on ventral side; apical part broader (Fig. 45). Brown, with head, lateral sides of pronotum and thin transverse basal band on elytra orange-brown (Fig. 12). Larger (TL: 5.3–5.8 mm) species from central Yunnan........................................................................................................................................................................... C. mopanshanensis sp. nov. 10. Median lobe of aedeagus in lateral view in shape of letter “Γ” (Figs 55, 67)...................................... 11 - Median lobe of aedeagus more sickle- or hook-shaped...................................................... 12 11. Median lobe of aedeagus in mid-length with distinct trapezoidal swelling on ventral side; apical part narrow; apex pointed, turned dorsally (Fig. 55). Brown, with orange-brown lateral sides of pronotum and thin comb-like shaped transverse basal band on elytra (Fig. 19). Larger (TL: 5.0– 5.9 mm) species from Yunnan and western Guizhou....... C. rimosus Guignot, 1952 - Median lobe of aedeagus in mid-length without any swelling, medially sinuous on dorsal side; apical part broader, narrowing continuously to straight apex (Fig. 67). Brown, with orange-brown head, lateral sides of pronotum and broad transverse basal band on elytra (Fig. 26). Larger (TL: 5.5 mm) species from southwestern Guizhou................ C. xiniudong sp. nov. 12. Median lobe of aedeagus straight in middle three fifths of its length; apical fifth strongly curved, hook-shaped (Fig. 47). Head and pronotum brown, elytra pale brown with broad orange transverse basal band (Fig. 13). Smaller (TL: 4.6–4.9 mm) species from northern Guangdong........................................................... C. nanlingensis sp. nov. - Median lobe of aedeagus curved in basal three fourths of its length; apical fourth straight or sinuous, but never hook-shaped.................................................................................................… 13 13. Median lobe of aedeagus in apical third almost straight or slightly turned ventrally (Figs 31, 33, 43) …................ 14 - Median lobe of aedeagus in apical third distinctly curved dorsally............................................. 16 14. Median lobe of aedeagus in apical third slightly turned ventrally; distinctly narrowing to slender apical part (Fig. 43). Dark brown, with orange-brown clypeus, lateral sides of pronotum and thin transverse basal band on elytra (Fig. 11). Larger (TL: 5.6–6.1 mm) species from western Guizhou............................................... C. miaowangi sp. nov. - Median lobe of aedeagus in apical third straight, slightly but continually narrowing to skewed apex. Head and pronotum dark brown with orange clypeus and lateral sides of pronotum; elytra brown with broad orange transverse basal band. Comparatively smaller (TL: 4.6–5.6 mm) species....................................................................... 15 15. Median lobe of aedeagus in two thirds of its length with small tooth on ventral side (Fig. 33). Larger (TL: 5.2–5.6 mm) species from southeastern China............................................................. C. dentatipenis sp. nov. - Median lobe of aedeagus without tooth on ventral side (Fig. 31). Medium sized (TL: 4.6–5.3 mm) species from central and eastern China................................................................ C. chinensis Régimbart, 1899 16. Median lobe of aedeagus strongly arched; broad in basal two thirds of its length, very narrow in apical third (Fig. 39). Head and pronotum dark brown with orange clypeus and lateral sides of pronotum; elytra brown with comb-like shaped yellowish orange transverse basal band (Fig. 8). Larger (TL: 5.3–5.7 mm) species from eastern China and Japan... C. japonicus Sharp, 1884 - Median lobe of aedeagus weakly to moderately arched; at least in apical third continuously narrowing to apex.......... 17 17. Median lobe of aedeagus only weakly arched; narrowing continuously from basal part to apex; apex slightly turned ventrally (Fig. 29). Brown, with orange clypeus, lateral sides of pronotum and transverse basal band on elytra (Fig. 1). Medium sized (TL: 4.9–5.3 mm), widely distributed Oriental species reaching southern part of China........ C. bacchusi Wewalka, 1981 - Median lobe of aedeagus moderately arched; in basal half (or basal two thirds) broad, then narrowing to apex; apex not turned ventrally........................................................................................... 18 18. Median lobe of aedeagus broad in basal three fourths of its length, then narrowing to obtusely pointed apex (Fig. 37); lateral carina of median lobe with small spines in apical half (Fig. 37 aa). Head and pronotum dark brown with orange clypeus and lateral sides of pronotum; elytra brown with orange transverse basal band (Figs 5–6). Medium sized (TL: 4.7–5.5 mm), widely distributed Oriental species reaching China in southern Yunnan..................... C. diversistriatus sp. nov. (partim) - Median lobe of aedeagus broad in basal half of its length, then narrowing to obtusely pointed apex; lateral carina of median lobe without small spines in apical half...................................................................... 19 19. Median lobe of aedeagus broadest in mid-length, apical part relatively broad (Fig. 63). Dark brown, with orange clypeus, lateral sides of pronotum and thin transverse basal band on clypeus (Figs 23–24). Larger (TL: 5.1–5.9 mm) species from western Yunnan........................................................................ C. tengchongensis sp. nov. - Median lobe of aedeagus broadest in basal part, apical part narrow............................................. 20 20. Median lobe of aedeagus more arched; subapically nearly straight on dorsal side; apex very thin, distinctly turned dorsally (Fig. 57). Elytral stria 1 may be fragmented or absent basally. Dark brown, with orange lateral sides of pronotum and indistinct thin transverse basal band on elytra (Fig. 20). Females dimorphic. Larger (TL: 5.1–5.9 mm) species from western Yunnan........................................................................................... C. rosulae sp. nov. - Median lobe of aedeagus less arched; in apical half distinctly curved on dorsal side; apex not turned dorsally (Figs 41, 53). Head and pronotum dark brown with orange clypeus and lateral sides of pronotum; elytra brown, sometimes with slightly paler base............................................................................................... 21 21. Median lobe of aedeagus more arched, distinctly curved throughout its whole length (Fig. 41). Larger (TL: 5.1–5.7 mm) species from northern Myanmar and western Yunnan, China.................................... C. malaisei Guignot, 1954 - Median lobe of aedeagus less arched, in midpart nearly straight (Fig. 53). Larger (TL: 4.8–5.8 mm) species from southern Yunnan, China and neighbouring areas of northeastern Laos and northern Vietnam................ C. puzhelongi sp. nov. 22. Each elytron with six complete, well impressed discal striae and 1–4 short striae in between; short striae may be fragmented into several strioles or absent; submarginal stria present, long. Dark brown, with orange clypeus, lateral sides of pronotum and transverse basal band on elytra (Fig. 5). Median lobe of aedeagus sickle-shaped; broad in basal three fourths of its length, then narrowing to obtusely pointed apex (Fig. 37); lateral carina of median lobe with small spines in apical half (Fig. 37 aa). Medium sized (TL: 4.7–5.5 mm), widely distributed Oriental species reaching China in southern Yunnan............................................................................................... C. diversistriatus sp. nov. (partim) - Each elytron with 11 complete, shallowly impressed discal striae; submarginal stria fragmented into several short strioles or absent. Brown, with orange head, lateral sides of pronotum and broad transverse basal band on elytra (Fig. 27). Median lobe of aedeagus broad, club-shaped, with two protuberances on dorsal side; apex beak-shaped (Fig. 69). Larger (TL: 5.4–5.7 mm) species from southeastern China.......................................... C. zimmermanni Gschwendtner, 1934, Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 276-278, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Zimmermann, A. (1920) Bemerkenswerte Neuerwerbungen des Zoologischen Museums in Hamburg. Haliplidae, Dytiscidae et Gyrinidae. Entomologische Blatter, 16, 224 - 234.","Sharp, D. (1882) On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Dublin Society, Series 2, 2, 179 - 1003, pls. 7 - 18. https: // doi. org / 10.5962 / bhl. title. 9530","Balfour-Browne, J. (1947) The aquatic Coleoptera of Manchuria (Weymarn collection). The Annals and Magazine of Natural History, Eleventh Series, 13 (1946), 433 - 460. https: // doi. org / 10.1080 / 00222934608654567","Regimbart, M. (1880) The new Dytiscidae and Gyrinidae collected during the recent scientific Sumatra-expedition. Notes from the Leyden Museum, 2, 209 - 216.","Guignot, F. (1952) Description de dytiscides inedits de la collection Regimbart. Revue Francaise d'Entomologie, 19, 17 - 31.","Regimbart, M. (1899) Revision des Dytiscidae de la region Indo-Sino-Malaise. Annales de la Societe Entomologique de France, 68, 186 - 367.","Sharp, D. (1884) The water-beetles of Japan. The Transactions of the Entomological Society of London, 1884, 439 - 464.","Wewalka, G. (1981) Drei neue Arten der Gattung Copelatus aus Indien (Dytiscidae, Col.). Koleopterologische Rundschau, 55, 65 - 70.","Guignot, F. (1954) Entomological results from the Swedish expedition 1934 to Burma and British India. Coleoptera: Haliplidae et Dytiscidae. Recueillis par Rene Malaise. Arkiv for Zoologi, 6 (32), 563 - 567."]}

Copelatus sp. (Fig. 28) Material examined. CHINA: Hongkong: 6 ♀, Lantau Isl., Ngong Ping vill., Po Lin Monastery env., 22°15.2-5′N 113°54.6′E, 480-590 m, stream, 26.-28.vi.2007, J. Hájek & J. Růžička leg. (NMPC). Diagnosis. Medium sized (TL: 4.5–4.8 mm), oblong-oval species. Head testaceous, with dark band along eyes and infuscation on frons between eyes; pronotum brown blackish, laterally broadly testaceous; elytra yellow orangish with two irregular transverse blackish bands, one medially and one subapically. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: all striae beginning at base; stria 1 longest; striae 2–5 shorter, ending subapically; stria 6 shortest ending at apical fourth; submarginal stria long, beginning before elytral mid-length (Fig. 28). Comments on the classification. Based on presence of six discal and a submarginal stria on each elytron, the species can be included in the C. irinus species group. With the distinctive yellow-black colour pattern of elytra, it could not be associated with any species currently known from the Sino-Japanese region and may represent an undescribed species. However, without a male available for the study, we prefer to leave this taxon unidentified at the species level. Collection details. All specimens were collected at night in a small, shaded stream flowing in subtropical broadleaved forest (Fig. 80). Despite considerable efforts of our colleagues, the species was never collected again; most streams in the area are currently captured in pipes and dried (P. Aston, pers. comm.). Distribution. The species is known only from one locality on Lantau Island, Hongkong., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 276, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696

Copelatus chinensis Régimbart, 1899 stat. rest. (Figs 2–3, 31–32) Copelatus chinensis Régimbart, 1899: 298. Copelatus collocallosus Falkenström, 1932: 192, syn. nov. Copelatus collocallosus Falkenström, 1933: 14; synonymy by Gschwendtner (1939: 40). Type locality. Copelatus chinensis: Chine: Chang-Yang [China, Hubei Province, Changyang Tujia Autonomous County]. Copelatus collocallosus: “ China: NO Szechuan” [China, northeast Sichuan Province or Chongqing Municipality]. Type material. Copelatus chinensis: Holotype ♂ (MNHN), labelled: “Chang- / Yang [hw] // MUSEUM PARIS / COLL MAURICE REGIMBART / 1908 [p] // TYPE [red label, p] // chinensis Rég. [hw] // GUIGNOT det., 19 [p] 51 [hw] / Copelatus / japonicus Sharp [hw]”. Copelatus collocallosus: Holotype ♀ (NHRS), labelled: “Kina / N. O. Szechuan [p] // Sven Hedins / Exp. Ctr. Asien / Dr Hummel [p] // 22.5 [hw] // Typus [red label with black frame, p] // Cop. collocallosus / n. sp. / Typ. [hw] / det. Falkenström [p] // 5606 / E91 [blue label, p] // NHRS/JLKB / 000027137 [p]”. Additional material examined. CHINA: Hunan: 1 ♂, 1 ♀, 80 km N Dayong, Yanjiajie, 27.-29.v.2005, O. Nakládal leg. (NMPC); 2 ♂, 1 ♀, Shaoyang, Chengbu County, Jinzishan forest farm, Shuangjiangkou, 26.3046N 110.4961E, 1371 m, 24.viii.2020, Z. Jiang leg. (SYSU). Shandong: 1 ♀, Qingdao City, 17.ix.1994, Ji & Wang leg.; 1 ♀, Taishan Nat. Res., 200 m, 18.x.1994, Ji & Wang leg.; 1 ♂, Taishan Nat. Res., 420 m, 19.x.1994, Ji & Wang leg. (all NHMW). Zhejiang: 45 spec., West Tianmu Shan (Mts.) reserve, border of secondary mixed forest nr entrance of reserve, 30°18.9′N 119°26.5′E, 320 m, pool, 23.vi.-6.vii.2017, J. Hájek & J. Růžička leg. (NMPC, SNUC, ZSMG); 1 ♂, 1 ♀, Quzhou, Kecheng distr., Lankeshan Mt., 28.8781N 118.9199E, 118 m, 18.iii.2020, Z. Jiang leg. (SYSU); 1 ♂, Quzhou, Qujiang distr., Tongshanyuan reservoir, 29.1300N 118.9434E, 93 m, 14.iii.2020, Z. Jiang leg. (SYSU). Diagnosis. Medium sized (TL: 4.6–5.3 mm), oblong-oval species. Head with reddish clypeus, frons and vertex darkened, brown blackish; pronotum brown blackish, laterally broadly testaceous; elytra brown with broad, irregularly shaped, basal orange band reaching suture. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: all striae beginning at base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth (Fig. 2). Median lobe of aedeagus in lateral view sickle-shaped, narrowing in apical fourth to skewed, dorsally slightly extended apex; dorsal and ventral side of apical part straight (Fig. 31). Parameres moderately broad, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 32). Female similar to male, strioles on pronotum more numerous. Comments on the classification. Guignot (1952) synonymized C. chinensis with C. japonicus Sharp, 1884 based on the drawing of median lobe of the latter species by Balfour-Browne (1947). However, the dissection of the holotype of C. chinensis revealed that the genitalia of both taxa are quite different (see Figs 31 and 39). Therefore, we reinstate C. chinensis as a valid species. Copelatus collocallosus was described twice, based on a single teneral female (Fig. 3); the first brief description (Falkenström 1932) was subsequently supplemented with a differential diagnosis from C. chinensis: pale colouration, different body shape, indistinct punctation, small number of extremely short strioles on the pronotum, rather long submarginal stria (Falkenström 1933). Gschwendtner (1939) was the first who considered C. collocallosus as a synonym of C. chinensis; however, probably based on synonymy of C. chinensis with C. japonicus by Guignot (1952), Satô (1982) mentioned C. collocallosus as a synonym of C. japonicus – a state which was largely accepted until now (cf. Nilsson 1995, Nilsson & Hájek 2022a). However, our study confirmed specific status of C. chinensis (see above). Further, in accordance with Gschwendtner (1939), the comparison of the C. collocallosus holotype with the extensive material of C. chinensis showed that both taxa are morphologically indistinguishable, including identical punctation of dorsal surface, presence of strioles on pronotum and length of elytral striae. Therefore, we consider C. collocallosus as a junior subjective synonym of C. chinensis, although we are aware that the identity of C. collocallosus is doubtful as the teneral female does not possess characters usable for species identification – the species of the C. japonicus complex are recognisable predominantly based on male genitalia. Anyway, the synonym of C. chinensis and C. collocallosus also seems reasonable from a biogeographical point of view: C. chinensis is widely distributed in Central China, and its type locality in Hubei lies only ca. 100 apart from the border of Chongqing Municipality (a presumed type locality of C. collocallosus). Collection details. In Tianmushan (Zhejiang), Copelatus chinensis was collected in number in exposed side pool of a river with sandy bottom (Fig. 71); few specimens were found also in shaded forest puddle with muddy bottom. Distribution. Central and eastern China (Hubei, Hunan, Shandong, Sichuan or Chongqing, and Zhejiang provinces) (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 253-254, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Regimbart, M. (1899) Revision des Dytiscidae de la region Indo-Sino-Malaise. Annales de la Societe Entomologique de France, 68, 186 - 367.","Falkenstrom, G. A. (1932) Vorlaufige Mitteilung uber die neuen Halipliden und Dytisciden, von Dr. D. Hummel in den Jahren 1927 - 30 wahrend Dr. Sven Hedins China-Expedition eingesammelt. Entomologisk Tidskrift, 53, 191 - 192.","Falkenstrom, G. A. (1933) Schwedisch-chinesische wissenschaftliche Expedition nach den nordwestlichen Provinzen Chinas, unter Leitung von Dr. Sven Hedin und Prof. Su Ping-chang. Insekten gesammelt vom schwedischen Arzt der Expedition Dr. David Hummel 1927 - 1930. 15. Coleoptera. 1. Haliplidae und Dytiscidae. Arkiv for Zoologi, 27 A (1), 1 - 22.","Gschwendtner, L. (1939) Monographie der palaarktischen Dytisciden. X. Erganzungen und Register. Koleopterologische Rundschau, 25, 23 - 69.","Guignot, F. (1952) Description de dytiscides inedits de la collection Regimbart. Revue Francaise d'Entomologie, 19, 17 - 31.","Sharp, D. (1884) The water-beetles of Japan. The Transactions of the Entomological Society of London, 1884, 439 - 464.","Balfour-Browne, J. (1947) The aquatic Coleoptera of Manchuria (Weymarn collection). The Annals and Magazine of Natural History, Eleventh Series, 13 (1946), 433 - 460. https: // doi. org / 10.1080 / 00222934608654567","Nilsson, A. N. (1995) Noteridae and Dytiscidae: Annotated check list of the Noteridae and Dytiscidae of China (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 35 - 96.","Nilsson, A. N. & Hajek, J. (2022 a) A World Catalogue of the family Dytiscidae, or the Diving Beetles (Coleoptera, Adephaga). Version 1. I. 2022. Distributed as a PDF file via Internet. Available from: http: // www. waterbeetles. eu (accessed 20 January 2022)"]}

Copelatus mopanshanensis Jiang, Zhao & Hájek sp. nov. (Figs 12, 45–46) Type locality. China, Yunnan Province, Xinping Yi and Dai Autonomous County, Mopan Mountain National Forestry Park, 23°56′18.71″N 101°59′17.16″E, ca. 2520 m. Type material. Holotype ♂ (ZSMG), labelled: “ China: Yunnan, Mo Pan shan / Liao Wa Ta, 2526m, 19.v.2011 / 23.93853 N 101.98810 E, Song / Keking M (1398) [p] // DNA / M.Balke / 6576 [p, green typing] // HOLOTYPE / COPELATUS / mopanshanensis sp. nov. / Jiang, Zhao & Hájek det. 2021 [red label, p]”. Paratypes: 1 ♂, 1 ♀, same label data as holotype (NMPC, ZSMG); 1 ♂, 3 ♀, labelled: “ CHINA: Yunnan Province / Mopanshan Mt., Yuelianghu / 23.947N 101.965E / 1973 m, 19.v.2011 / Keqing Song leg. [p]” (SYSU). All paratypes with the respective paratype label. Description of male holotype. Habitus (Fig. 12) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, convex. Dorsal surface shiny. Colouration. Head brownish black, clypeus and two oval spots on vertex reddish brown; pronotum brownish black, laterally broadly orange-brown, anterior and posterior margin somewhat orange-brown translucent; elytra brown, lateral sides and base indistinctly paler – orange-brown; appendages orange-brown; ventral side brownish black. Head. Moderately broad, ca. 0.61× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present also in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.76), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading thin but distinct, except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum without strioles, surface baso-laterally only with indistinct wrinkles. Centre of disc with shallowly impressed medial longitudinal groove. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six complete discal and one submarginal longitudinal striae present on each elytron: striae 2–4 beginning at base, striae 1, 5–6 beginning slightly posteriorly to base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fifth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes, laterally with oblique strioles; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short oblique strioles; reticulation consisting of elongate, oblique, polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view sickle-shaped, broad in basal two thirds of its length, with bulge on ventral side in two thirds; apical third slender, bisinuous, apex obtusely pointed (Fig. 45). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 46). Female. Identical to male in habitus. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Pronotum baso-laterally with several irregular longitudinal strioles. Very short and sparse irregular strioles present between striae in basal half of elytra. Variability. In addition to differences of female described above, no substantial variability can be seen in the limited number of specimens available to us. Measurements. TL: 5.3–5.8 mm (mean value: 5.6 ± 0.2 mm); holotype: 5.8 mm. TL-h: 4.8–5.4 mm (mean value: 5.0 ± 0.2 mm); holotype: 5.4 mm. MW: 2.6–2.9 mm (mean value: 2.8 ± 0.1 mm); holotype: 2.9 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. mopanshanensis sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: median lobe is broad in basal two thirds; apical part is slenderer, bisinuous. The most similar genitalia are those of Copelatus felicis sp. nov., but the median lobe is broader and with distinct swelling on ventral side in three fourths of its length, and the apical part is slenderer in the latter species (see Figs 35 and 45). Etymology. The species is named after the Mopan Shan mountains where it was collected. The specific epithet is an adjective in the nominative singular. Distribution. A species endemic to China, so far known only from two very close localities in Mopan Shan mountains in central Yunnan (Fig. 82).

Copelatus nanlingensis Hájek, Jiang, & Jia sp. nov. (Figs 13, 47–48) Type locality. China, Guangdong Province, Nanling National Nature Reserve, Dadongshan mountains, ca. 24°56.0′N 112°42.9′E, 690 m. Type material. Holotype ♂ (NMPC), labelled: “ CHINA, GUANGDONG Prov., / Nanling National Nature Reserve / Dadongshan, 18-21.iv.2013 / (shallow pool with sandy bottom) / 24°56.0′N 112°42.9′E, 690 m / J. Hájek & J. Růžička leg. [p] // HOLOTYPE / COPELATUS / nanlingensis sp. nov. / Hájek, Jiang & Jia det. 2021 [red label, p]”. Paratypes: 2 ♀, same label data as holotype and the respective paratype label (NMPC, SYSU). Description of male holotype. Habitus (Fig. 13) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, convex. Dorsal surface shiny. Colouration. Head brownish black, clypeus and two indistinct oval spots on vertex reddish brown; pronotum brownish black, laterally broadly orange-brown; elytra brown, laterally somewhat paler, base with not well delimited very broad orange band reaching suture; appendages orange brown; ventral side brownish black. Head. Moderately broad, ca. 0.62× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.62), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading thin but distinct, except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum basolaterally and especially laterally with several, irregularly distributed short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six complete discal and one submarginal longitudinal striae present on each elytron: all striae beginning at base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fifth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes, laterally with oblique strioles; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only very close to metaventrite. Metacoxal plates covered with short oblique strioles; reticulation consisting of elongate, oblique, polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view straight in middle three fifths, with dorsally bent hooklike apical part narrowing to pointed apex (Fig. 47). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 48). Female. Identical to male in habitus and sculpture. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Variability. No substantial variability can be seen in the limited number of specimens available to us. Measurements. TL: 4.6–4.9 mm (mean value: 4.8 ± 0.2 mm); holotype: 4.9 mm. TL-h: 4.0– 4.5 mm (mean value: 4.3 ± 0.2 mm); holotype: 4.4 mm. MW: 2.2–2.4 mm (mean value: 2.4 ± 0.1 mm); holotype: 2.4 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. nanlingensis sp. nov. in the C. japonicus complex. Within the complex, the new species can be recognised based on smaller size and very broad basal orange band on elytra; however, the indubitable identification of C. nanlingensis sp. nov. is only possible based on the shape of male genitalia: straight median lobe with hook-like apical part is very characteristic for the new species, and unique among Chinese Copelatus. Collection details. All type specimens were collected at the border of shallow pool with sand bottom and numerous decaying tree leaves (Fig. 74). Etymology. The species is named after the Nanling mountain range where it was collected. The specific epithet is an adjective in the nominative singular. Distribution. So far known only from the type locality in Dadongshan mountains, Nanling mountain range, northern Guangdong, China (Fig. 82)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 264-265, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696

[Copelatus takakurai Satô, 1985] Comments. This Japanese species was mentioned from China without any precise data by Zeng (1989). We were not able to study the respective material, but we consider the presence of the species in China rather improbable. We believe that Zeng probably studied Copelatus chinensis from central-eastern China (see under that species). Therefore, we remove C. takakurai Chinese fauna., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 271, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Sato, M. (1985) The genus Copelatus of Japan (Coleoptera: Dytiscidae). Transactions of the Shikoku Entomological Society, 17, 57 - 67.","Zeng, H. (1989) Classification of Dytiscidae (Insecta: Coleoptera) - A study of the collections of Dytiscidae from major museums in China. Unpublished PhD Thesis, Department of Biology, University of Sun Yat-sen University, Guangzhou, 152 pp. [in Chinese with English abstract]"]}

Copelatus diversistriatus Jiang, Hájek & Jia, sp. nov. (Figs 5–6, 37–38) Type locality. China, Yunnan Province, Pu’er City, Laiyanghe, Xinzhai village, ca. 22°37′52″N 101°07′55″E; 1487 m. Type material. Holotype, ♂ (SYSU), labelled: “ CHINA: Yunnan Province / Pu’er City, Laiyanghe / Xinzhai Village / 22.631N, 101.132E / 1487 m, 21.v.2011 / Keqing Song leg. [p] // HOLOTYPE / COPELATUS / diversistriatus sp. nov. / Jiang, Hájek & Jia det. 2021 [red label, p]”. Paratypes: 2 ♀, same label data as holotype (SYSU); 1 ♂, labelled: “ China: Yunnan, Lai yang he / Xin zhai, 1481m, 21.v.2011, / N22.63161 E101.13255, / S. Keqing (IRS 1399) [p] // DNA / M.Balke / 6587 [p, green typing]” (ZSMG); 1 ♂, labelled: “ YUNNAN 1500-2500m / 25.22N 98.49E 17-24.5 / GAOLIGONG mts. / Vít Kubáň leg. 1995 [p]” (ZSMG); 6 ♂, 11 ♀, labelled: “ China, Yünnan prov.; / Gaoligong Shan; 2800m a.s.l. / ca 30km E Tengchong; meadow / holokren [Sic!] spring, muddy pools / 24.10.1999, leg. J. Šťastný [p]” (JSCL); 1 ♀, labelled: “ CHINA: Yünnan, Xishuangbanna / ca. 10km NW Menglun / 7.11.1999, ca. 700 m / leg. Jäch, et al. (CWBS 359) [p]” (NHMW); 2 ♂, 8 ♀, labelled: “ CHINA: Yünnan, Xishuangbanna / ca. 10km NW Menglun / 7.11.1999, ca. 700 - 800 m / leg. Jäch, et al. (CWBS 360) [p]” (NHMW); 3 ♂, labelled: “ CHINA: Yunnan province, / REHAI hot springs, 5.VI. 2007 / 6 km SW of TENGCHONG, / 24°57.1′N 098°26.2′, 1400 m, / J. Hájek & J. Růžička leg. // individually collected in small / pool with clay bottom, and on / plants and shrubs margin of / grove above the rice fields [p]” (NMPC); 1 ♂, labelled: “ CHINA: Yunnan Province / Baoshan City / Gaoligong Nature Park / 24.91N, 98.81E / 1751 m, 22.v.2016 / Y. Tang & R. Zhang leg. [p]” (SYSU); 1 ♂, labelled: “ CHINA: YUNNAN Prov. / 6 km SSW Tengchong / Rehai Hot Springs / 24°56.9′N 98°26.9′E, 1445 m / J. Hájek & J. Růžička leg. // 22.vi.2016; individually from / vegetation, in artificial watering / pools and in stream; / border of ruderal and orchards [p]” (NMPC); 21 ♂, 13 ♀, labelled: “ CHINA: YUNNAN PROV. / 14 km SE Tengchong / Renjiafen env., 2025-2145 m / 24°56.0-5′N, 98°35.0-7′E, / J. Hájek & J. Růžička leg. // 23.vi.2016 / individually from pool / border of ruderal, orchards and / secondary mixed forest [p]” (IZCAS, NHRS, NMPC, SNUC, ZFMK); 1 ♂, 1 ♀, labelled: “ CHINA: YUNNAN Prov. / TONGBIGUAN env., 1340-1380 m / 24°36.0-37.0′N, 97°35.1-4′E, / J. Hájek, J. Růžička leg. // 24.-26.vi.2016; individually from / ruderal vegetation, from fungi / on dead wood, in Bos excre- / ments, in puddles near river [p]” (NMPC); 3 ♂, 5 ♀, labelled: “ CHINA: YUNNAN Prov. / 6.5- 5.2 km W Tongbiguan / 24°36.6-8′N, 97°35.5-36.4′E, / 1290-1325 m / J. Hájek & J. Růžička leg. // 25.+ 27.vi.2016; / individually from puddle, / vegetation, fungi; / broadleaved tropical forest [p]” (NMPC); 1 ♂, labelled: “ CHINA: Yunnan Province / Lvchun County / roadside ditches and terraces / 22.8856N, 102.3264E / 1443.5 m, 1.v.2021 / Z. Jiang, Z. Yang, Z. Mai & / B. Huang leg. [p]” (SYSU). All paratypes with the appropriate printed red label. Additional material examined. LAOS: 1 ♂, 1 ♀, Attapeu Prov., Annam Highlands Mts., Dong Amphan NBCA, Nong fa (crater lake) env., 15°05.9′N 107°25.6′E, 1160 m, 30.iv.-6.v.2010, J. Hájek leg. (NMPC). MYANMAR: 2 ♂, Shan State, 35 km N Aungban, 20°55.20′N 96°33.60′E, 1320 m, flight intercept trap, 31.v.-8.vi.2002 (NHMW, NMPC); 85 spec., Shan State, NE Mintaingbin Forest Camp, 20°55.640′N 96°33.634′E, 1290 m, puddles, 14.- 20.vi.2004, H. Shaverdo leg. (NHMW, NMPC); 81 spec., Shan State, SE Mintaingbin Forest Camp, forest pools and leaf litter near stream, 17.vi.2004, H. Shaverdo leg. (NHMW, NMPC); 52 spec., Mandalay Reg., Mogok Township, S Panlin vill., W slopes of Mt. Taung Mae, ca. °58′09.7″N 96°27′11″E, 1710 m, 12.vi.2014, H. Schillhammer leg. (NHMW). THAILAND: 1 ♀, Nakhon Ratchasima Prov., Khao Yai NP, 8.-10.xii.2011, J. Šťastný leg. (ZSMG); 1 ♂, Phitsanulok Prov., Nakhon Thai Distr., Phu Hin NP, Rong Kla, 16°59′49.1″N 101°00′34.8″E, in waterfall, 7.iii.2016, A. Damaška leg. (NMPC). See the Variability section. Description of male holotype. Habitus (Fig. 5) oblong oval, with continuous outline, broadest in anterior 1/3 of elytral length, slightly convex. Dorsal surface shiny. Colouration. Head dark brown, clypeus and two oval spots on vertex rufous; pronotum dark brown, laterally broadly orange; elytra brown, laterally somewhat paler, with moderately broad, irregularly shaped, basal orange band not reaching suture; appendages orange-brown; ventral side dark brown to black. Head. Moderately broad, ca. 0.62× width of pronotum, trapezoidal. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions. Pronotum. Strongly transverse (width/length ratio = 3.03), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading very thin and indistinct. Reticulation similar to that of head. Punctation double; rows of coarse setigerous punctures present along anterior margin, close to lateral sides, several punctures present also in shallow baso-lateral depressions along basal margin; fine puncture smaller and sparser than on head, spread throughout whole surface. Pronotum, except for centre of disc, with numerous, irregularly distributed short longitudinal or oblique strioles. Centre of disc with shallowly impressed median longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Ten discal and one submarginal longitudinal striae present on each elytron: all striae beginning more or less at base; striae 1, 3, 5, 7, 9–10 complete; stria 1 longest, ending close to apex; striae 3, 5, 7, 9 somewhat shorter, ending subapically, stria 10 ending at apical fourth; striae 2, 4, 6 short, presented only in basal third of elytral mid-length, apically usually fragmented into several short strioles; stria 8 shortest, present only in basal fourth of elytra; submarginal stria long, beginning at elytral mid-length and ending at apical fourth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation consisting of shallow, hardly perceptible polygonal meshes. Metaventrite with microsculpture consisting of polygonal meshes; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with long, longitudinal strioles; reticulation consisting of elongate, oblique polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures; coarse setigerous punctures present medially on ventrite III, and medio-laterally on ventrite VI. Male genitalia. Median lobe of aedeagus in lateral view sickle-shaped; broad in basal three quarters, slightly narrowing in apical quarter; curved in basal third, then almost parallel-sided until apical quarter, and then curved to obtusely pointed apex (Fig. 37); lateral carina of median lobe with small spines in apical half (Fig. 37 aa). Parameres moderately broad, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 38). Female. Identical to male in habitus. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Short irregular strioles present between stria 1 and lateral margin in anterior third of elytra in some specimens. Variability. The specimens of the new species vary slightly in dorsal surface colouration, especially in extent of orange basal elytral band, which may be comb-like shaped. The specimens vary also in extent of striolation on pronotum. However, the most apparent variability is in the elytral striation: short striae 2, 4, 6, 8 vary in length, occupying from one fourth to nearly a half of elytral length; those striae may be also fragmented into several short strioles, or partly or completely reduced, thus the beetles have only six dorsal elytral striae (see below). On the other hand, several short strioles may present between regular striae. While most of the specimens from Yunnan and specimens from central Thailand agree with the holotype in the elytral striation, one population from Yunnan (6.5– 5.2 km W Tongbiguan) and the specimens from southern Laos have the even elytral striae 2, 4, 6, 8 partly reduced, and the majority of specimens from Myanmar have elytra with six discal striae only (Fig. 6). The male genitalia are identical in all studied specimens. Although we have no doubts that all material belongs to one nominal species, due to the large variability between populations and extended area of distribution, we have decided to exclude the specimens from outside Yunnan province, China from the type material. Measurements. TL: 4.7–5.5 mm (mean value: 5.2 ± 0.2 mm); holotype: 5.2 mm. TL-h: 4.3–5.0 mm (mean value: 4.7 ± 0.2 mm); holotype: 4.8 mm. MW: 2.3–2.8 mm (mean value: 2.6 ± 0.1 mm); holotype: 2.6 mm. Differential diagnosis. Based on the presence of 10 dorsal striae and a submarginal stria on each elytron, the new species can be classified within the C. erichsonii Guérin-Méneville species group. This large group is in the Oriental region represented with only three species from India and Indonesia respectively (Nilsson & Hájek 2022a). From all these species, C. diversistriatus sp. nov. clearly differs in the short even elytral striae 2, 4, 6 and 8. However, the reduction of elytral striae to six indicates that C. diversistriatus sp. nov. is in fact more closely related to species of the C. japonicus Sharp complex in the C. irinus species group. This fact is confirmed with the molecular analysis (M. Balke et al., unpublished data).The similar reduction of elytral striae was recently documented and discussed by Manuel et al. (2018) in Neotropical Copelatus. Within the members of the C. japonicus complex, the specimens of the new species with six dorsal striae on each elytron can be undoubtedly recognized only based on the median lobe of male genitalia, which is simple, sickle-shaped, broad in basal three fourths, and then slightly narrowed to obtusely pointed apex. Collection details. Copelatus diversistriatus sp. nov. was collected predominantly in small temporary pools or ditches with muddy bottom, both densely vegetated and without any vegetation (Fig. 73). In western Yunnan, it was repeatedly collected syntopically with C. malaisei Guignot, 1954. Etymology. The species name is composed from the Latin adjectives diversus (-a, -um) (= diverse), and striatus (-a, -um) (= with striae), referring to the diverse length of odd and even elytral striae. Distribution. Widely distributed species, recorded from southwest China (southern Yunnan) (Fig. 81), neighbouring Shan State in eastern Myanmar, as well as Mandalay Region in central Myanmar, central Thailand (Nakhon Ratchasima and Phitsanulok provinces) to southern Laos (Attapeu province)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 256-258, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Nilsson, A. N. & Hajek, J. (2022 a) A World Catalogue of the family Dytiscidae, or the Diving Beetles (Coleoptera, Adephaga). Version 1. I. 2022. Distributed as a PDF file via Internet. Available from: http: // www. waterbeetles. eu (accessed 20 January 2022)","Manuel, M., Deler-Hernandez, A., Megna, Y. S. & Hajek, J. (2018) Copelatus Erichson from the Dominican Republic, with the description of a new species, comments on elytral striation and faunistic notes on Antillean species (Coleoptera: Dytiscidae: Copelatinae). Zootaxa, 4399 (3), 371 - 385. https: // doi. org / 10.11646 / zootaxa. 4399.3.7","Guignot, F. (1954) Entomological results from the Swedish expedition 1934 to Burma and British India. Coleoptera: Haliplidae et Dytiscidae. Recueillis par Rene Malaise. Arkiv for Zoologi, 6 (32), 563 - 567."]}

Copelatus parallelus Zimmermann, 1920 (Figs 16, 51–52) Copelatus parallelus Zimmermann, 1920: 226. Type locality. “Setsu, Zentral-Japan” [Japan, Honshu, Osaka Prefecture, Settsu, ca. 34°46′N 135°33′]. Type material. Holotype ♂, originally deposited in Zoologisches Museum, Centrum für Naturkunde, Universität Hamburg, Hamburg, Germany; destroyed during WW2. Material examined. CHINA: Hebei: 1 ♀, Baiyangdian, Mapu vill., 16.vii.-11.viii.2012, J. Wang & P. Wei leg. Hubei: 1 ♀, Wuchang, 17.v.1961, Z. Pu leg. Hunan: 1 ♂, Huaihua, Yushuwan, 17.vi.1965, Z. Chen leg. Shanghai: 1 ♀, 20.iv.1950 (all SYSU). Diagnosis. Small species (TL: 3.5–4.0 mm), oblong-oval species, lateral sides of elytra nearly parallel in basal two thirds of their length. Head reddish; pronotum dark brown with reddish anterior margin and lateral sides; elytra brownish black, with broadly orange base and thin lateral orange band broadening posteriorly to lateral subapical spot. Pronotum with several short strioles basally and laterally. Each elytron with five longitudinal discal striae: all striae beginning at base and ending approximately in apical fifth of elytral length (Fig. 16). Median lobe simple, sickle shaped, broad (widest at middle), only slightly narrowing to beak-shaped apex (Fig. 51). Parameres broad, ‘D’-shaped; apex long and slender; apical lobes long, club-shaped (Fig. 52). Female similar to male in habitus. Distribution. A species described from Japan and recently recorded also from Korea (Jung et al. 2020). First records from China (Hebei, Hubei, Hunan and Shanghai) (Fig. 82)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 266, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Zimmermann, A. (1920) Bemerkenswerte Neuerwerbungen des Zoologischen Museums in Hamburg. Haliplidae, Dytiscidae et Gyrinidae. Entomologische Blatter, 16, 224 - 234.","Jung, S. W., Min, H. K. & Lee, D. - H. (2020) Aquatic beetles fauna in Nohwa and Bogil Islands, and Copelatus parallelus (Coleoptera: Dytiscidae) and Scirtes sobrinus (Coleoptera: Scirtidae) new to South Korea. Animal Systematics, Evolution, and Diversity, 36 (2), 128 - 138. https: // doi. org / 10.5635 / ASED. 2020.36.2.004"]}

Copelatus bacchusi Wewalka, 1981 (Figs 1, 29–30) Copelatus bacchusi Wewalka, 1981: 66. Type locality. “Indien, Utar Pradesh, Kumaun, Haldwani” [India, Uttarakhand State, Kumaon Division, Haldwani, ca. 29°13′N 79°31′E]. Type material. Holotype ♂, deposited in BMNH (not studied). Material studied. CHINA: Hainan: 1 ♂, Jianfeng Mts., Tian Chi, 750 m, 23.i.1996, Ji & Wang leg. (NHMW). Yunnan: 1 ♂, Xishuangbanna, ca. 15 km W Menglun, ca. 700-800 m, 5.xi.1999, M. Jäch et al. leg. (NHMW). Diagnosis. Medium sized (TL: 4.9–5.3 mm), oblong-oval species. Head with testaceous clypeus, frons and vertex usually darkened, brown; pronotum orange-brown to dark brown, laterally broadly testaceous; elytra brown with testaceous lateral sides and broad basal testaceous band not reaching suture. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: striae 1–5 beginning at base and ending close to apex, odd striae somewhat longer than even ones; stria 6 shorter, absent at base and ending at apical fourth; submarginal stria rather short, presenting only in third fourth of elytral length (Fig. 1). Median lobe of aedeagus in lateral view weakly sickle-shaped with apex slightly skewed on ventral side (Fig. 29). Parameres slender, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 30). Female similar to male, strioles on pronotum more numerous. Distribution. The species was described, and for 40 years known only from the Uttarakhand State in northern India. Recently, Shaverdo et al. (2021) provided additional records not only from Bhutan and Nepal in the Himalayan Region, but also from Myanmar, Thailand and Vietnam, suggesting that C. bacchusi is widespread in the continental southeast Asia. The present records from two distant Chinese provinces confirm this statement. First records from China (Hainan and Yunnan provinces) (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 253, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Wewalka, G. (1981) Drei neue Arten der Gattung Copelatus aus Indien (Dytiscidae, Col.). Koleopterologische Rundschau, 55, 65 - 70.","Shaverdo, H., Wewalka, G., Stastny, J., Hendrich, L., Fery, H. & Hajek, J. (2021) New records of diving beetles and corrections updating the Catalogue of Palearctic Dytiscidae (Coleoptera). Aquatic Insects, 42 (2), 179 - 196. https: // doi. org / 10.1080 / 01650424.2021.1903509"]}

Copelatus xiniudong Jiang, Hájek & Jia sp. nov. (Figs 26, 67–68) Type locality. China, Guizhou Province, Anlong County, Dushan Township, Xiniu Dong cave env., ca. 25°18.9′N 105°35.3′E, ca. 1030 m. Type material. Holotype ♂ (SYSU), labelled: “ DZ州ṘAEẸ山犀牛洞 / ffi洞口‖ 50 ※水潭/Ṗ志洪 Ā 2009- VII-14 // CHINA: Guizhou Province / Anlong County, Dushan / Township, Xiniudong / pool about 50 metres from / entrance of the cave / 14.vii.2009, Zhihong Xue leg. [p] // HOLOTYPE / COPELATUS / xiniudong sp. nov. / Jiang, Hájek & Jia det. 2021 [red label, p]”. Paratypes: 1 ♂, 1 ♀, same label data as holotype and the respective paratype label (SYSU). Description of male holotype. Habitus (Fig. 26) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, slightly convex. Dorsal surface shiny. Colouration. Head dark brown, clypeus orange brown; pronotum dark brown, laterally broadly orange brown; elytra dark brown, with very broad, irregularly shaped, transverse basal orange brown band not reaching suture; appendages orange brown; ventral side dark brown. Head. Moderately broad, ca. 0.64× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.76), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading very thin but distinct except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum baso-laterally and especially laterally with several, irregularly distributed short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal groove. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six discal and one submarginal longitudinal striae present on each elytron: all striae beginning at base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth. Reticulation similar to that of head and pronotum. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation imperceptible. Metaventrite with microsculpture consisting of polygonal meshes; lateral parts of metaventrite (“metasternal wings”) tongueshaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short, longitudinal strioles and some transverse wrinkles; reticulation consisting of elongate, longitudinal and oblique polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present antero-medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view in shape of letter “Γ”, broadest at basal part, middle part narrower, curved at apical third, narrowing to pointed apex; middle part ca. 1.75 times longer than basal part (Fig. 67). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 68). Female. Identical to male in habitus and sculpture. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Variability. No substantial variability can be seen in the limited number of specimens available to us. Measurements. TL: 5.5 mm; TL-h: 4.8 mm. MW: 2.6 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. xiniudong sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: the median lobe of aedeagus of C. xiniudong sp. nov. is most similar to that of C. rimosus. However, it is without any swelling in mid-length; medially the median lobe is sinuous on dorsal side; its apical part is broader, narrowing continuously to straight apex (see Figs 55 and 67). In addition, C. xiniudong sp. nov. is characteristic with the broad pale transverse basal band on elytra, while the basal band of C. rimosus is usually narrow (or even indistinct). Etymology. The species is named after the type locality, Xiniudong – a karst cave in Guizhou Province, China. The specific epithet is a noun in the nominative singular. Distribution. So far known only from the type locality in southwestern Guizhou, China (Fig. 83)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 274-275, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696

Copelatus felicis Hájek, Jiang, & Jia, sp. nov. (Figs 7, 35–36) Type locality. China, Yunnan Province, Yulong Naxi Autonomous County, Baishui village, ca. 27°08′N 100°15′E, 2800 m. Type material. Holotype ♂ (NMPC), labelled: “ China, Yünnan prov.; / 2800m, 20 km N LIJIANG; / Baishui; gravely, muddy / stream (0,5m wide) / 21.10.1999, leg. J. Šťastný [p] // HOLOTYPE / COPELATUS / felicis sp. nov. / Hájek, Jiang & Jia det. 2021 [red label, p]”. Paratype: 1 ♂, same label data as holotype and the respective paratype label (JSCL). Description of male holotype. Habitus (Fig. 7) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, convex. Dorsal surface shiny. Colouration. Head brownish black, clypeus reddish brown; pronotum brownish black, laterally broadly orangebrown, anterior and posterior margin somewhat orange-brown translucent; elytra brown, base and lateral sides indistinctly paler; appendages orange-brown; ventral side brown blackish. Head. Moderately broad, ca. 0.63× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present also in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.54), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading thin but distinct, except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum without strioles, surface baso-laterally only with indistinct wrinkles. Centre of disc with shallowly impressed medial longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six discal and one submarginal longitudinal striae present on each elytron: striae 2–4 beginning at base, striae 1 and 5 beginning slightly posteriorly to base, stria 6 beginning with few punctures; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning at elytral mid-length and ending at apical fifth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes; lateral parts of metaventrite (“metasternal wings”) tongueshaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short oblique strioles; reticulation consisting of elongate, oblique, polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view broad in basal three fourths, broadest in third fourth where distinct shallow swelling present on ventral side; apical fourth slender and bisinuous, apex pointed (Fig. 35). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 36). Female. Unknown. Variability. No substantial variability can be seen between the two specimens available. Measurements. TL: 5.5 mm; TL-h: 5.0 mm. MW: 2.6 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. felicis sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: median lobe is broad in basal three fourths, on ventral side with distinct swelling, apical part is slender, bisinuous. The most similar genitalia are those of Copelatus mopanshanensis sp. nov.; but the median lobe is slenderer and without swelling on ventral side in basal three fourths of its length, and its apical part is broader in the latter species (see Figs 35 and 45). Collection details. Both type specimens were collected in rather polluted, ca. 0.5 m wide, muddy gutter surrounding the garden of famous local Chinese herbalist He Shixiu (called also “Dr. Ho”) in Baishui village (J. Šťastný, pers. comm.). At the locality it was syntopical with C. rimosus Guignot, 1952. Etymology. The species is dedicated to its collector, Jaroslav Šťastný (Liberec, Czech Republic), well known specialist on diving beetles. The Latin word felix is a translation of the surname “Šťastný”, meaning “the happy one” in Czech. The specific epithet is a noun in the genitive singular. Distribution. So far known only from the type locality in Yulong Xueshan mountains, northern Yunnan, China (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 258-260, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Guignot, F. (1952) Description de dytiscides inedits de la collection Regimbart. Revue Francaise d'Entomologie, 19, 17 - 31."]}

Copelatus tengchongensis Hájek, Jiang & Jia sp. nov. (Figs 23–24, 63–64) Type locality. China, Yunnan Province, 12 km NE Tengchong, Beihai Wetlands, Zing Hai lake env., ca. 25°07.5′N 98°33.3′E, ca. 1730 m. Type material. Holotype ♂ (NMPC), labelled: “ China, Yünnan prov. / 10 km NE Tengchong; Behai [Sic! See the type locality.] / ZingHai lake env; / small flowing pools, dense veget. / 27.10.1999, leg. J. Šťastný [p] // HOLOTYPE / COPELATUS / tengchongensis sp. nov. / Hájek, Jiang & Jia det. 2021 [red label, p]”. Paratypes: 2 ♂, 4 ♀, same label data as holotype (JSCL, NMPC); 7 ♂, 7 ♀, labelled: “ CHINA (Yunnan) / Baoshan Pref., Gaoligong Shan / 65 km NNE Tengchong 1750 m / 25°35′20″N, 98°40′21″E / (small brook at edge of sec. / mixed forest) / 27.VIII.2009 D.W.Wrase (10G) [p]” (NMPC, SYSU, ZSMG). All paratypes with the respective paratype label. Description of male holotype. Habitus (Fig. 23) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, slightly convex. Dorsal surface shiny. Colouration. Head brown blackish, clypeus reddish brown; pronotum brown blackish, laterally broadly orangebrown, anterior and posterior margin orange translucent; elytra dark brown, paler laterally, base with distinct, orange, comb-like shaped transverse band reaching neither lateral margin nor suture; appendages orange-brown; ventral side brown blackish. Head. Moderately broad, ca. 0.63× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.69), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading very thin and indistinct. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin.Pronotum baso-laterally and especially laterally with irregular wrinkles and very few short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six discal and one submarginal longitudinal striae present on each elytron: striae 1 and 5 beginning slightly posteriorly to base; striae 2–4, 6 beginning at base; stria 1 longest, ending close to apex; striae 2–5 ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes, laterally with oblique strioles; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with long, oblique strioles; reticulation consisting of elongate, longitudinal or oblique polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present antero-medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side.Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view simple, sickle-shaped, broadest at mid-length due to shallow swelling on ventral side; in apical third narrowing continuously to pointed apex (Fig. 63). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 64). Female. Identical to male in habitus. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Females dimorphic; smooth form differs from male in more developed striolation laterally on pronotum; striolate form submatt, with long strioles covering pronotum and elytra except for apical fifth (Fig. 24). Variability. All specimens of the type series are rather uniform. There is only slight variability in dorsal surface colouration, especially in extent and brightness of pale basal band on elytra. Minor variability can be seen also in number and length of strioles presenting laterally on pronotum. Measurements. TL: 4.7–5.5 mm (mean value: 5.3 ± 0.2 mm); holotype: 5.0 mm. TL-h: 4.2–5.1 mm (mean value: 4.8 ± 0.2 mm); holotype: 4.5 mm. MW: 2.3–2.8 mm (mean value: 2.6 ± 0.1 mm); holotype: 2.5 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. tengchongensis sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: C. tengchongensis sp. nov. is characteristic with the median lobe broadest in midpart and the apical part only slightly narrowing to apex (Fig. 63). Etymology. The new species is named after its area of occurrence – Tengchong County, where both known localities of the species lie. The specific epithet is an adjective in the nominative singular. Distribution. The species is so far known only from two close localities on western side of the Gaoligong mountains, western Yunnan, China (Fig. 83).

Copelatus rosulae Hájek, Jiang, & Jia sp. nov. (Figs 20, 57–58) Type locality. China, Yunnan Province, Lushui County, Pianma Township, ca. 26°01′N 98°37′E, 1900 m. Type material. Holotype ♂ (SYSU), labelled: “ 云南省泸水县片Ljdz / 26.01N 98.62E / 1908m 2016-V-19 / 唐余丹 张 Ṅae // CHINA: Yunnan Province / Lushui County / Pianma Township / 26.01N, 98.62E / 1908 m, 19.v.2016 / Y. Tang & R. Zhang leg. [p] // HOLOTYPE / COPELATUS / rosulae sp. nov. / Hájek, Jiang & Jia det. 2021 [red label, p]”. Paratypes: 12 ♂, 17 ♀, same label data as holotype (SYSU); 1 ♀, labelled: “ CHINA: Yunnan Province / Lushui County / Pianma Township, S316 / 25.9956N, 98.6548E / 2504.9 m, 15.v.2021 / Z. Jiang, Z. Yang & Z. Mai leg. [p]” (SYSU); 7 ♂, 6 ♀, labelled: “ CHINA: YUNNAN Prov. / Gaoligong Mts NNR / E of Kongshu vill., 2035-2230m / 25°43.2-5′N, 98°34.4-40.0′E / J. Hájek & J. Růžička leg. [p] // 1.vii.2016; pasture / individually from densely / vegetated pool near river [p]” (JSCL, NHMW, NMPC, ZSMG). All paratypes with the respective paratype label. Description of male holotype. Habitus (Fig. 20) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, slightly convex. Dorsal surface shiny. Colouration. Head dark brown, clypeus reddish brown; pronotum brown blackish, laterally broadly orangebrown; elytra dark brown, base with rather indistinct, orange brown transverse band not reaching suture; appendages orange brown; ventral side brown blackish. Head. Moderately broad, ca. 0.63× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.82), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading thin but distinct except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum basolaterally and especially laterally with irregular wrinkles and several short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six discal and one submarginal longitudinal striae present on each elytron: stria 1 fragmented in basal fourth, ending close to apex; striae 2–4, 6 beginning at base; stria 5 beginning slightly posteriorly to base; striae 2–5 ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes, laterally with elongate strioles; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short, oblique strioles; reticulation consisting of elongate, longitudinal or oblique polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present antero-medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side.Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view simple, sickle-shaped, continuously narrowing to pointed apex (Fig. 57). Parameres moderately broad, ‘D’-shaped; apex short and broad; apical lobes long, clubshaped (Fig. 58). Female. Identical to male in habitus. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Females dimorphic; smooth form differs from male in more developed striolation laterally on pronotum; striolate form submatt, with long but rather fine and sparsely distributed strioles in basal two thirds of elytra. Variability. All specimens of the type series are rather uniform. There is only slight variability in dorsal surface colouration, especially in extent and brightness of pale basal band on elytra. Minor variability can be seen also in number and length of strioles presenting laterally on pronotum. Elytral stria 1 is complete (beginning at base) in some specimens, but it is fragmented or absent up to mid-length of elytra in other specimens. Measurements. TL: 5.1–5.9 mm (mean value: 5.5 ± 0.2 mm); holotype: 5.6 mm. TL-h: 4.7–5.1 mm (mean value: 4.9 ± 0.1 mm); holotype: 5.1 mm. MW: 2.5–2.8 mm (mean value: 2.7 ± 0.1 mm); holotype: 2.7 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. rosulae sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: with the shape of simple slender arc, the median lobe of the new species is very similar to that of C. malaisei, however, the arc is deeper in the C. rosulae sp. nov., and the narrowing apical part is longer and slenderer with pointed apex turned distinctly dorsally (see Figs 41 and 57). In addition, most of the specimens of C. rosulae sp. nov. have elytral stria 1 fragmented or absent at the base, while all specimens of C. malaisei have elytral stria 1 complete (beginning at elytral base); striolate females of C. rosulae sp. nov. have sparsely distributed shorter strioles in basal two thirds of elytra, while all studied females of C. malaisei have densely distributed longer strioles on pronotum and elytra except for the apex. Collection details. The specimens from Kongshu were collected in a deep, exposed pool near the river; the diameter of the pool was ca. 3 m, littoral was densely vegetated, bottom muddy (Fig. 77). Etymology. The species is dedicated to Jan Růžička (Praha, Czech Republic), a specialist on Silphidae and Leiodidae, who accompanied one of us (JH) on many Chinese collecting trips. The Latin noun rosula (-ae, femininum) is a translation of the surname “Růžička”, meaning “a small rose” in Czech. The specific epithet is a noun in the genitive singular. Distribution. So far known only from two close localities in Gaoligong mountains, western Yunnan, China (Fig. 82)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 269-270, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696

Copelatus malaisei Guignot, 1954 (Figs 9–10, 41–42) Copelatus malaisei Guignot, 1954: 566. Type locality. “Kambaiti” [ Myanmar, Kachin State, Kambaiti Pass, ca. 25°24′N 98°09′E]. Type material. Holotype ♂ (NHRS), labelled: “N. E. BURMA / Kambaiti. 7000 ft. [p] / 5/4 1934 [hw] / R. MALAISE [p] // 5684 / E91 + [blue label, p] // Type [red label with black frame, p] // F. Guignot det., 19 [p] 53 [hw] / Copelatus / malaisei Guign / Type ♂ [hw] // NHRS-JLKB / 000027122”. Allotype ♀ (NHRS), labelled: “N. E. BURMA / Kambaiti. 7000 ft. [p] / 8/4 1934 [hw] / R. MALAISE [p] // 5685 / E91 + [blue label, p] // Allotype [red label with black frame, p] // F. Guignot det., 19 [p] 53 [hw] / Copelatus / malaisei Guign / Allotype ♀ [hw] // NHRS-JLKB / 000027123”. Additional material examined. CHINA: Yunnan: 1 ♂, Gaoligong Mts., 24.57N 98.45E, 2200-2500 m, 8.- 16.v.1995, V. Kubáň leg. (ZSMG); 5 ♂, 1 ♀, Gaoligong Shan Mts., 30 km E Tengchong, 2800 m, meadow, helocrene spring, muddy pools, 24.x.1999, J. Šťastný leg. (JSCL, NMPC); 1 ♂, 4 ♀, 14 km SE Tengchong, Renjiafen env., 24°56.0-5′N 98°35.0-7′E, 2025-2145 m, shallow pool with clayey bottom, 23.vi.2016, J. Hájek & J. Růžička leg. (NMPC); 10 ♂, 7 ♀, Baoshan, Gaoligong Nature Park, 24.91N 98.81E, 1751 m, 22.v.2016, Y. Tang & R. Zhang leg. (SYSU); 2 ♂, 5 ♀, Tengchong, Houqiao Town, Xintang, 25.1303N 98.2572E, 1974 m, 12.v.2021, Z. Jiang, Z. Yang & Z. Mai leg. (SYSU). Diagnosis. Larger (TL: 5.1–5.7 mm), oblong-oval species. Head brownish black, usually with reddish clypeus and two oval spots on vertex; pronotum brownish black, laterally broadly testaceous and with testaceous translucent anterior margin; elytra brown with somewhat paler base. Pronotum with only very few short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: striae 5–6 beginning slightly posteriorly from base; stria 1 longest, ending close to apex, odd striae somewhat longer than even ones; stria 6 shortest, ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth (Fig. 9). Median lobe of aedeagus in lateral view simple, sickle shaped, regularly curved to bluntly pointed apex (Fig. 41). Parameres moderately broad, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 42). Females dimorphic; striolate form with whole pronotum and elytra except for apex densely covered with short irregular longitudinal strioles (Fig. 10). Collection details. At the locality Renjiafen, C. malaisei was collected in ruderal habitat, in a small (diameter ca. 1 m), temporary pool with clayey bottom and dense vegetation; the species was syntopical there, although less abundant, with C. diversistriatus sp. nov. In Tengchong, C. malaisei was found in a marsh with dense emergent water macrophytes (Fig. 79). Distribution. A species occurring in the northeastern Myanmar (Kachin State) and western Yunnan, China (Gaoligong Shan Mts.). First record from China (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 260-261, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Guignot, F. (1954) Entomological results from the Swedish expedition 1934 to Burma and British India. Coleoptera: Haliplidae et Dytiscidae. Recueillis par Rene Malaise. Arkiv for Zoologi, 6 (32), 563 - 567."]}

Copelatus japonicus Sharp, 1884 (Figs 8, 39–40) Copelatus japonicus Sharp, 1884: 445. Type locality. “Kiishiu” [ Japan, Honshu Island, Wakayama Prefecture]. Type material. Syntype ♂ (BMNH), labelled: “ Copelatus / japonicus. / Type D.S. / Japan. Lewis [hw] // Type [round label with red frame, p] // Sharp Coll / 1905-313.”; Syntype ♀ (BMNH), labelled: “Kii, 1879 / Wada [hw] // Japan. / G. Lewis. / 1910–320. [p] // Copelatus / japonicus. [hw] // Copelatus / japonicus, / ♀ Sharp. / teste. D.Sharp. [hw]”. Additional material examined. CHINA: Shanghai: 1 ♂, 1 ♀, Jiading District, Jiading new town, 10.ix.2021, D. Zhou leg. (SYSU). Diagnosis. Larger (TL: 5.3–5.7 mm), oblong-oval species. Head brown, with reddish clypeus and two oval spots on vertex; pronotum brown, laterally broadly orange, anterior and posterior margin orange translucent; elytra pale brown on disc, base and lateral sides yellowish brown. Pronotum with only several short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: all striae beginning at base; stria 1 longest, ending close to apex, odd striae somewhat longer than even ones; stria 6 shortest, ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth (Fig. 8). Median lobe of aedeagus in lateral view simple, sickle shaped, strongly curved; broad in basal half and slender in apical half; apex pointed (Fig. 39). Parameres slender, ‘C’-shaped; apex short and broad; apical lobes moderately long, club-shaped (Fig. 40). Female similar to male; strioles on pronotum more numerous, microreticulation of pronotum and elytra slightly more impressed. Comments on the classification. This Japanese species was recorded from several Chinese provinces by various authors (see Nilsson 1995 for summary), also under the names C. chinensis and C. collocallosus which were synonymized with C. japonicus by Guignot (1952) and Satô (1985) respectively. However, the study of the type material of C. chinensis proved that it is a valid species separate from C. japonicus, while the extensive material collected recently in various localities in southern China belongs to numerous taxa new to science. At present, we are aware of only a single reliable record of C. japonicus from China – Shanghai, presented above. Distribution. A species occurring in Japan, South Korea and eastern China (Shanghai) (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 260, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Sharp, D. (1884) The water-beetles of Japan. The Transactions of the Entomological Society of London, 1884, 439 - 464.","Nilsson, A. N. (1995) Noteridae and Dytiscidae: Annotated check list of the Noteridae and Dytiscidae of China (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.), Water beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 35 - 96.","Guignot, F. (1952) Description de dytiscides inedits de la collection Regimbart. Revue Francaise d'Entomologie, 19, 17 - 31.","Sato, M. (1985) The genus Copelatus of Japan (Coleoptera: Dytiscidae). Transactions of the Shikoku Entomological Society, 17, 57 - 67."]}

Copelatus sociennus J. Balfour-Browne, 1952 (Figs 21, 59–60) Copelatus sociennus J. Balfour-Browne in Guignot, 1952: 26; Jäch & Easton 1998: 44 (Macao: Friendship Monument). Copelatus bangalorensis Vazirani, 1970: 311; Zeng 1989: 98 (Guangxi: Guilin, Yanshan; Shanghai; Yunnan: Xishuangbanna). Type locality. “ China: (Hong Kong)”. Type material. Holotype ♂ (BMNH), labelled: “833 [hw, round label] // Hong Kong / [on reverse:] 48 / 60 [hw] // Copelatus / discoideus Shp [hw] // Copelatus / japonicus / ♂ Sharp. / det. J.Balfour-Browne [hw, blue ink] // Copelatus ♂ / chinensis Rég. [hw] / J.Balfour-Browne det. [p] / Det. from Descr. [p] ii.1946 [hw] // HOLOTYPE ♂ / COPELATUS / sociennus / J.Balfour-Browne, 1952 / labelled by J. Hájek 2016 [p, red label]”. Paratypes: 1 ♂ (BMNH), labelled: “Bowring / China [hw] // 457 / 17/8/49 [hw, round label] // Copelatus / japonicus / ♂ Sharp. / det. J.Balfour-Browne [hw, blue ink] // Copelatus ♂ / chinensis Rég. [hw] / J.Balfour-Browne det. [p] / Det.from Descr. [p] ii.1946 [hw]”; 1 ♂ (BMNH), labelled: “Bowring / China [hw] // 457 / 7/8/53 [hw, round label] // Copelatus /? chinensis Rég. [hw] / J.Balfour-Browne det. [p]”; 1 ♀ (BMNH), labelled: “Bowring / China [hw] // 457 / 9/6/52 [hw, round label]”. All paratypes provided with additional label “ PARATYPE ♂ [♀, respectively] / COPELATUS / sociennus / J.Balfour-Browne, 1952 / labelled by J. Hájek 2016 [p, red label]”. Additional material examined. CHINA: Guangdong: 3 ♂, 3 ♀, Zhuhai, Hengqin Island, 10.vii.2006, F. Jia leg. (SYSU); 4 ♀, Zhuhai, Qi’ao Island, 13.-15.vii.2005, Y. Jia leg. (SYSU); 2 ♂, Zhuhai, back mountain of Sun Yat-Sen University, 5.-8.vii.2011, F. Jia leg. (SYSU). Guangxi: 6 ♂, 9 ♀, Jingxi, Bangliang Nature Reserve, 6.viii.2010, J. Huang leg. (SYSU); 1 ♂, Shiwandashan National Forest Park, 21°54.4′N 107°54.2′E, 300 m, pool, 5.-9.iv.2013, M. Fikáček, J. Hájek & J. Růžička leg. (NMPC); 1 ♂, Du’an County, Sanzhiyang Township, Keli vill., 24.vi.2013, Tian, Lin, Yin, Huang leg. (SYSU). Hainan: 1 ♂, 3 ♀, 6 km W Dongxing, 50 m, 25.i.1996, M. Jäch leg. (NHMW). Macao: 1 ♂, Coloane Isl., Siac Pai Van Agric. Park, 19.iii.1998, E. Easton leg. (NHMW); 1 ♀, Cotai Ecological Zone, 5.vii.2017, F. Jia leg. (SYSU); 1 ♂, Cotai Ecological Zone, 10.x.2020, F. Jia & W. Xie leg. (SYSU). Yunnan: 3 ♀, Xishuangbanna, xii.1985 (SYSU). Diagnosis. Larger (TL: 5.2–6.1 mm), broadly oblong-oval species. Head dark brown, clypeus and anterior part of frons usually paler, reddish; pronotum dark brown, laterally broadly reddish; elytra dark brown, with broad, comblike shaped, basal orange band not reaching suture, band confluent with orange-brown lateral part of elytra usually laterally from stria 3, apical fifth of elytra orange-brown. Pronotum with short longitudinal strioles laterally. Each elytron with six complete discal striae and one submarginal stria: all striae beginning at base; stria 1 and 4 ending close to elytral apex; striae 2–3 and 5 ending subapically; stria 6 shortest, ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth (Fig. 21). Median lobe of aedeagus in lateral view sickle-shaped with apex slightly turned dorsally, near mid-length with broad spoon-like process on dorsal side and finger-like process on ventral side (Fig. 59). Parameres broad, ‘D’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 60). Female similar to male, microreticulation of dorsal side slightly more impressed. Collection details. The single specimen from Shiwandashan (Guangxi) was collected in a small pool of artificial stream in the resort; specimens from Hainan were found in roadside rainwater ditches and small man-made ground water pool in rubber plantation (Jäch & Ji 1998). Distribution. A species occurring in the Indian subcontinent (especially in the Himalayan Area), China and continental Southeast Asia. In China, it is recorded from southern and eastern part of the country (Guangxi, Hong Kong, Macao, Shanghai, Taiwan, Yunnan). First records from Guangdong and Hainan (Fig. 83)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on page 271, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Guignot, F. (1952) Description de dytiscides inedits de la collection Regimbart. Revue Francaise d'Entomologie, 19, 17 - 31.","Jach, M. A. & Easton, E. R. (1998) Water beetles of Macao (Coleoptera). In: Jach, M. A. & Ji, L. (Eds.) Water beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, pp. 43 - 50","Vazirani, T. G. (1970) Contributions to the study of aquatic beetles (Coleoptera). VII. A revision of Indian Colymbetinae (Dytiscidae). Oriental Insects, 4 (3), 303 - 362. https: // doi. org / 10.1080 / 00305316.1970.10433967","Zeng, H. (1989) Classification of Dytiscidae (Insecta: Coleoptera) - A study of the collections of Dytiscidae from major museums in China. Unpublished PhD Thesis, Department of Biology, University of Sun Yat-sen University, Guangzhou, 152 pp. [in Chinese with English abstract]","Jach, M. A. & Ji, L. (1998) China water beetle survey (1995 - 1998), pp. 1 - 23. In: Jach, M. A. & Ji, L. (Eds.) Water beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, 371 pp."]}

Copelatus puzhelongi Jiang, Hájek & Jia sp. nov. (Figs 17–18, 53–54) Type locality. China, Yunnan Province, Pu’er City, Laiyanghe Nature Reserve, ca. 22°36.4′N 101°00.4′E. Type material. Holotype ♂ (SYSU), labelled: “ 云南Ḃ洱ǨÑ河保护区 / 2007.VII.29 / Āφ人:DZṂ AE // CHINA: Yunnan Province / Pu’er City / Laiyanghe Nature Reserve / 29.vii.2007, Fenglong Jia leg. [p] // HOLOTYPE / COPELATUS / puzhelongi sp. nov. / Jiang, Hájek & Jia det. 2021 [red label, p]”. Paratypes: 4 ♂, 4 ♀, same data as holotype (NMPC, SYSU); 1 ♀, labelled: “ China: Yunnan Prov. / Nabanhe N. R. / Bengganghani / Shanshenmiao / N22.08.450 E100.35.289 [p] // Alt. 1750m / 12-XI-2008 / HU Jia-Yao & / TANG Liang leg. [p]” (SNUC); 1 ♂, labelled: “ China: Yunnan Prov. / Nabanhe N. R. / Shanshenmiao / Bengganghani / alt. 1700m, 27-IV-2009 / Jia-Yao Hu & / Zi-Wei Yin leg. [p]” (SNUC); 2 ♂, labelled: “ China: Yunnan Prov. / Nabanhe N. R. / Chuguohe / Bengganghani [p] // alt. 1750m, 28-IV-2009 / Jia-Yao Hu & / Zi-Wei Yin leg. [p]” (NMPC, SNUC); 1 ♂, 2 ♀, labelled: “ CHINA: Yunnan Province / Lvchun County / Huanglianshan Reservoir / 22.8898N 102.2952E / 1717.3m, 30.iv.2021 / Z. Jiang, Z. Yang, Z. Mai & / B. Huang leg. [p]” (SYSU); 1 ♂, 2 ♀, labelled: “NE LAOS, Hua Phan Prov. / BAN SALUEI, Phu Phan Mt. / 20°15′N 104°02′E, / 1500–2000 m, / J. Bezděk leg. 26.iv.-11.v.2001 [p]” (NMPC); 2 ♂, labelled: “ LAOS –NE, Houa Phan prov. / 20°12′01-30″ N 104°00′ / 34-55″ E, 1750-1850 m, / PHOU PANE Mt. / 8.v.2008, Vít Kubáň lgt. [p]” (NMPC); 1 ♂, 1 ♀, labelled: “LAOS-NE, Houa Phan prov., / 20°12′01-30″N 104°00′34- / 55″E, 1750-1850m, / PHOU PANE Mt. 4.+ 10.vi. / 2009, Vít Kubáň lgt. [p]” (NMPC); 1 ♂, labelled: “LAOS-NE, Xieng Khouan prov., / 19°38.20′N 103°20.20′E, / Phonsavan (30km NE), / Phou Sane Mt., 10.-30.v.2009, / 1400-1600m, V. Kubáň leg. [p]” (NMPC). 1 ♂, 1 ♀ + 6 spec., labelled: “N-Vietnam – pass 8 km / NW Sa Pa, 22°21’10’’N / 103°46’01’’E, 2010 m, / second. forest, 12.VIII. / 2013, V. Assing [7b+2]” (ZMHB); 1 ♂, labelled: “ Vietnam: Cao Bang Prov., Tinh / Tuc, Son Dong, Nui Pia Oac / Nature Reserve, 850-1300m, / 9-15.v.2014, 22°37′55″N / 105°52′98″E, A. Skale [p] // DNA / M. Balke / 6665 [p, green typing]” (ZSMG). All paratypes with the respective paratype label. Description of male holotype. Habitus (Fig. 17) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, slightly convex. Dorsal surface shiny. Colouration. Head dark brown, clypeus and two oval spots on vertex orange; pronotum dark brown, laterally broadly orange, anterior and posterior margin orange translucent; elytra orange-brown, base and lateral sides indistinctly paler, orange; appendages orange; ventral side dark brown. Head. Moderately broad, ca. 0.62× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present at frontal level of eyes, and antero-laterally to eyes in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.92), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading very thin but distinct except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum baso-laterally and especially laterally with several, irregularly distributed short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal groove. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six discal and one submarginal longitudinal striae present on each elytron: striae 1–4 beginning at base, striae 5–6 beginning slightly posteriorly to base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fourth. Reticulation similar to that of head and pronotum. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation imperceptible. Metaventrite with microsculpture consisting of polygonal meshes; lateral parts of metaventrite (“metasternal wings”) tongueshaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short, longitudinal strioles and some transverse wrinkles; reticulation consisting of elongate, longitudinal and oblique polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present antero-medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view simple, sickle-shaped; in middle part almost straight on ventral side, regularly curved to bluntly pointed apex (Fig. 53). Parameres moderately broad, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 54). Female. Identical to male in habitus. Protibia simple, not angled basally and only slightly broadened distally; pro- and mesotarsomeres not broadened, without adhesive setae. Females dimorphic; smooth form differs from male in more developed striolation presenting laterally on pronotum; striolate form matt, one female from Pu’er with long strioles on elytra except for apical fourth (Fig. 18), females from Laos additionally with long strioles covering whole surface of pronotum. Variability. All specimens of the type series are rather uniform. There is only slight variability in dorsal surface colouration – the pale base of elytra is not perceptible in some specimens and elytra are uniformly orange-brown; some specimens are somewhat darker with elytra brown. Minor variability can be seen also in number and length of strioles presenting laterally on pronotum. Measurements. TL: 4.8–5.8 mm (mean value: 5.3 ± 0.2 mm); holotype: 5.4 mm. TL-h: 4.4–5.3 mm (mean value: 4.8 ± 0.2 mm); holotype: 4.9 mm. MW: 2.2–2.9 mm (mean value: 2.6 ± 0.1 mm); holotype: 2.7 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. puzhelongi sp. nov. in the C. japonicus complex. Within the complex, the new species can be undoubtedly recognised only based on the shape of male genitalia: with the shape of simple slender arc, the median lobe of the new species is very similar to that of C. malaisei, however, the arc is shallower and in middle part almost straight on ventral side (see Figs 41 and 53). Etymology. The new species is dedicated to the late Dr. Zhelong Pu (SYSU), the founder of aquatic beetle taxonomy in China. The specific epithet is a noun in the genitive singular. Distribution. This species is so far known from the border area between China (southern Yunnan) (Fig. 82), Laos (Houaphanh and Xiangkhouang provinces) and Vietnam (Lao Cai province)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 267-268, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696

Copelatus miaowangi Hájek, Jiang, & Jia sp. nov. (Figs 11, 43–44) Type locality. China, Guizhou Province, Liupanshui City Region, 10 km W Liupanshui City, Yaoshang reservoir, ca. 26°36′N 104°47′E, ca. 1820 m. Type material. Holotype ♂ (IAECAS), labelled: “ CHINA: Guizhou / 10km W Lipanshui [Sic! See the type locality.] City / 27.7.1997, ca. 1800m / leg. M. Wang (CWBS 268) [p] // HOLOTYPE / COPELATUS / miaowangi sp. nov. / Hájek, Jiang & Jia det. 2021 [red label, p]”. Paratypes: 6 ♂, same label data as holotype and the respective paratype label (NHMW, NMPC, SYSU). Description of male holotype. Habitus (Fig. 11) oblong-oval, with continuous outline, broadest in anterior 1/3 of elytral length, convex. Dorsal surface shiny. Colouration. Head brownish black, clypeus reddish brown; pronotum brownish black, laterally broadly orangebrown, anterior and posterior margin somewhat orange-brown translucent; elytra brown with moderately broad, irregularly shaped, basal orange band not reaching suture; appendages orange-brown; ventral side brown. Head. Moderately broad, ca. 0.60× width of pronotum, semicircular. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and fine punctures spread sparsely on surface; row of coarse punctures present alongside inner margin of eyes, several punctures present also in fronto-clypeal depressions; fine punctures smaller and sparser on clypeus, becoming larger and more dense posteriorly. Pronotum. Transverse (width/length ratio = 2.80), broadest between posterior angles, lateral margins moderately curved. Lateral sides with beading thin but distinct, except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally close to sides, several punctures present also in shallow baso-lateral depressions along basal margin. Pronotum basolaterally and especially laterally with several, irregularly distributed short longitudinal strioles. Centre of disc with shallowly impressed medial longitudinal smooth line. Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, then distinctly narrowing to apex. Six complete discal and one submarginal longitudinal striae present on each elytron: striae 2–4, 6 beginning at base, striae 1 and 5 beginning slightly posteriorly to base; stria 1 longest, ending close to apex; striae 2–5 somewhat shorter, ending subapically, even striae generally shorter than odd striae; stria 6 ending at apical fourth; submarginal stria long, beginning before elytral mid-length and ending at apical fifth. Reticulation similar to that of head and pronotum, but less impressed. Punctation consisting of coarse setigerous punctures and very fine sparse punctures; coarse punctures present along elytral striae and lateral margins of elytra. Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side; claws simple. Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation not perceptible. Metaventrite with microsculpture consisting of polygonal meshes, laterally with oblique strioles; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender. Metacoxal lines nearly complete, absent only close to metaventrite. Metacoxal plates covered with short oblique strioles; reticulation consisting of elongate, oblique, polygonal meshes. Metacoxal processes rounded at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally. Tuft of setae present medially on ventrites III–V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine, sparsely distributed punctures. Male genitalia. Median lobe of aedeagus in lateral view sickle-shaped, narrowing in apical third to obtusely pointed apex; dorsal side of apical part straight, ventral side slightly concave (Fig. 43). Parameres moderately broad, ‘C’-shaped; apex short and broad; apical lobes long, club-shaped (Fig. 44). Female. Unknown. Variability. All specimens of the type series are rather uniform. Minor variability can be seen in dorsal surface colouration, especially in the shape and extent of basal elytral band. The paratypes vary also slightly in number and extent of pronotal striolation. Measurements. TL: 5.6–6.1 mm (mean value: 5.8 ± 0.1 mm); holotype: 5.8 mm. TL-h: 5.0– 5.5 mm (mean value: 5.2 ± 0.1 mm); holotype: 5.2 mm. MW: 2.8–3.0 mm (mean value: 2.9 ± 0.1 mm); holotype: 2.9 mm. Differential diagnosis. Based on the presence of six dorsal striae and a submarginal stria on each elytron, the new species can be classified within Copelatus irinus species group. Elongate habitus, complete elytral striation and male median lobe without distinct process place C. miaowangi sp. nov. in the C. japonicus complex. Based on the shape of male genitalia, the new species is very similar to C. chinensis. It is, however, distinctly bigger than the latter species; and its median lobe has the slender apical part longer (ca. 1/3 of median lobe length), with dorsal side straight and ventral side slightly concave (see Figs 31 and 43). Collection details. The specimens of the type series were collected at the Yao Shang Reservoir; the bank had mud and sand bottom, with aquatic vegetation; it was slightly polluted, surrounded by agricultural fields (Jäch & Ji 1998). Etymology. The new species is dedicated to its collector, Miao Wang (Shenyang, China). The specific epithet is a noun in the genitive singular. Distribution. So far known only from the type locality in western Guizhou, China (Fig. 81)., Published as part of Jiang, Zhuo-Yin, Zhao, Shuang, Yang, Zhen-Yu, Jia, Feng-Long & Hájek, Jiří, 2022, A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae), pp. 251-295 in Zootaxa 5124 (3) on pages 261-262, DOI: 10.11646/zootaxa.5124.3.1, http://zenodo.org/record/6410696, {"references":["Jach, M. A. & Ji, L. (1998) China water beetle survey (1995 - 1998), pp. 1 - 23. In: Jach, M. A. & Ji, L. (Eds.) Water beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Osterreich and Wiener Coleopterologenverein, Wien, 371 pp."]}