A review of Copelatus Erichson, 1832 of Mainland China, with description of ten new species from the japonicus complex (Coleoptera: Dytiscidae: Copelatinae) Author Jiang, Zhuo-Yin 0000-0001-6825-4283 State Key Laboratory of Biocontrol and Institute of Entomology, Sun Yat-sen University, Guangzhou 510275, China. zhuoyin _ jiang @ 126. com; https: // orcid. org / 0000 - 0001 - 6825 - 4283 Author Zhao, Shuang Guangzhou Customs Technology Center, Nansha District, Guangzhou, China. Author Yang, Zhen-Yu Brilliant Landscaping and Gardening Company Limited, Macau. Author Jia, Feng-Long 0000-0003-2391-5038 State Key Laboratory of Biocontrol and Institute of Entomology, Sun Yat-sen University, Guangzhou 510275, China. fenglongjia @ aliyun. com; lssjfl @ mail. sysu. edu. cn; http: // orcid. org / 0000 - 0003 - 2391 - 5038 fenglongjia@aliyun.com Author Hájek, Jiří 0000-0001-5779-1542 Department of Entomology, National Museum, Cirkusová 1740, CZ- 193 00 Praha 9 - Horní Počernice, Czech Republic. jiri. hajek @ nm. cz; https: // orcid. org / 0000 - 0001 - 5779 - 1542 jiri.hajek@nm.cz text Zootaxa 2022 2022-04-04 5124 3 251 295 journal article 53387 10.11646/zootaxa.5124.3.1 de55f596-c349-4ca2-a826-0e2bad912aa3 1175-5326 6410696 67D4C618-C7C2-4FFC-925B-B260E11CD7B4 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 ).