Copelatus nanlingensis Hájek, Jiang, & Jia, 2022

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), Zootaxa 5124 (3), pp. 251-295 : 264-265

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 ).

Figures

FIGURE 82. Map of distribution of Copelatus in China Mainland.

FIGURES 13–16. Habitus of Copelatus in China. 13. C. nanlingensis sp. nov. (holotype ♂; Dadongshan, Guangdong); 14. C. oblitus (♂; Cotai Ecological Zone, Macao); 15. C. oblitus (♀; Lantau, Hongkong); 16. C. parallelus (♀; Shanghai). Scale bar 1 mm.

FIGURES 39–50. Male genitalia of Copelatus. 39, 41, 43, 45, 47, 49. median lobe in lateral view; 40, 42, 44, 46, 48, 50. paramere. 39–40. C. japonicus (Shanghai); 41. C. malaisei (a. Gaoligongshan, Yunnan; b. Renjiafen, Yunnan); 42. C. malaisei (Renjiafen, Yunnan); 43–44. C. miaowangi sp. nov. (paratype, Liupanshui, Guizhou); 45–46. C. mopanshanensis sp. nov. (holotype, Mopanshan, Yunnan); 47–48. C. nanlingensis sp. nov. (holotype, Dadongshan, Guangdong); 49–50. C. oblitus (Macao). Scale bar 0.5 mm.

FIGURES 71–78. Habitat of Copelatus in China. 71. Tianmushan, Zhejiang (C. chinensis); 72. Jinggangshan, Jiangxi (C. dentatipenis sp. nov.); 73. Tongbiguan, Yunnan (C. diversistriatus sp. nov.). 74. Dadongshan, Guangdong (C. nanlingensis sp. nov.); 75. Macao (C. oblitus in wet soil); 76. Dali, Yunnan (C. rimosus); 77. Kongshu, Yunnan (C. rosulae sp. nov.); 78. Danxiashan, Guangdong (C. oblitus and C. zimmermanni).