Zaitzevia tangliangi Jiang & Wang 2021, sp. nov.

Zaitzevia tangliangi Jiang & Wang sp. nov. (Figs 1–3) Type material (3 ♂♂, 2 ♀♀): Holotype: CHINA: ♂, labeled ‘ China: Hubei (ḋ北), Yichang City (fiȇ市), Wufeng Tujia Autonomous County (五峰ŀẋŭn治县), Wufeng Town (五峰Dz), Houhe N. R. (后河n然保护 区), 30°05′13″N, 110°33′09″E, H: 1129m, 19.VII.2018, Jiang Ri-Xin leg.’ (QUST). Paratype: 2 ♂♂, 2 ♀♀, with the same label data as the holotype (QUST). Description. Male. Body elongate, elliptical (Fig. 1A), black with tibiae, tarsi, tarsal claws and antennae reddishbrown. Dorsal surface shiny and punctuate, covered with sparse short setae. Sericeous tomentum is confined to following areas: head (both dorsal and ventral surface), pronotum, prosternum, outer part of elytra (include epipleura), outer parts of mesoventrite, metaventrite and abdomen (except median part) and surface of femora. Head (Fig. 2A), wider than long, dorsal surface covered with dense short setae and sparse big punctures, each puncture bearing a longer seta, the interspaces between the punctures about 2–3 times of the diameters of punctures. Clypeus evenly punctate with large punctures and covered with sparse long setae. Labrum transverse, shorter and broader than clypeus, covered with big punctures and long bristles at apical portion, anterior margin almost straight and anterolateral angles rounded. Antenna (Fig. 2C) short, with eight antennomeres; antennomere I slightly longer than wide, with several short setae; II distinctly longer than I, expanded, covered with several long setae, apical margin rounded with short setae; III longer than wide; IV–VII strongly transverse; VIII elliptical, elongate and strongly expanded, apex covered with dense long setae. Pronotum (Fig. 2B) wider than long, widest near base. Anterior margin arcuate with angles moderately produced and acute. Lateral margins finely curved. Basal margin trisinuate, emarginated before scutellum, posterior angles sub-orthogonal. Surface shiny, covered with sparse big punctures, each puncture with short seta; surface near apical angles microreticulate. Distinct longitudinal impression in the middle of the pronotum, short and about 1/3 length of pronotum, start from basal 1/3 and end to basal 2/3 of the pronotum; sublateral carinae thin, from base to 2/5 of pronotum, straight. Prosternal process (Fig. 2D) subtriangular with bluntly acuminated apex. Hypomera covered with dense short setae. Elytra (Fig. 2F) about twice as long as wide, subparallel in anterior 2/3, surface smooth and covered with sparse long setae. Each elytron with granulate carinae on strial intervals 5, 7 and 8, other intervals flat. Most areas from interval 5 to lateral margin include the epipleura covered with dense short setae, except the base of interval 5, apical parts of interval 1–4 covered with dense short setae; apical margin of elytra serrated. Hind wings well developed. Metaventrite (Fig. 2E), surface smooth with sparse short setae on disc; sides with sericeous tomentum. Median sulcus longitudinal, moderately wide extending from posterior margin to ca. 2/3 of metasternum. Sides of metaventrite around meso- and metacoxae with a series of distinct impressions of various lengths and shapes from transverse to circular. Abdomen with 5 visible sternites, sides of abdominal sternites with sericeous tomentum. Abdominal sternite V and VI granulated; apex of abdominal sternite V (Fig. 4F) broadly emarginate, and densely granulated, lateral sides serrated. Legs simple, femora swollen, surface covered with sericeous tomentum; inner side of tibiae with cleaning fringes; tarsi shorter than tibiae; tarsal claws simple. Aedeagus (Figs 4 A–C), slender and elongate, nearly symmetrical, apex of median lobe cuspidal. Parameres small and inconspicuous. Speculum gastrale as in Fig. 4D. Measurements: BL: 2.62–2.64 mm; HL: 0.34–0.36 mm, HW: 0.46–0.48 mm; PL: 0.68–0.74 mm, PW: 0.84– 0.92 mm; EL: 1.86–1.88 mm, EW: 1.10–1.12 mm. Female: externally similar to the male, apex of sternite V (Fig. 4G) rounded. Ovipositor as Fig. 4E. Measurements: BL: 2.54–2.62 mm; HL: 0.34–0.36 mm, HW: 0.48–0.50 mm; PL: 0.70–0.72 mm, PW: 0.86– 0.88 mm; EL: 1.90–1.94 mm, EW: 1.10–1.12 mm. Distribution and habitat. Known only from the type locality: Houhe Natural Reserve, Hubei Province, China, which is characterized by rich and diverse water environment (Figs 4A–F). Biology. All adults were collected by light trap, and no details are known about their habitat preferences. Etymology. This species is named in honor of Dr. Liang Tang (Shanghai Normal University, Shanghai, China). A teacher and also a good friend of the first author. Comparative diagnosis. Zaitzevia tangliangi sp. nov. is most similar to Z. xiongzichuni Jiang & Wang, 2020 from Yunnan Province by sharing similar body size and habitus characters, like the smooth elytra. The new species can be distinguished from Z. xiongzichuni by the following characters: 1) punctures of pronotum much thinner; 2) middle impression of pronotum much shorter, sublateral carinae thin and straight (cf. middle impression long and deep, sublateral carinae longer and curved at apical 1/ 2 in Z. xiongzichuni); 3) different form of aedeagus (apex of aedeagus of the new species is much wider than Z. xiongzichuni).Published as part of Jiang, Ri-Xin & Wang, Shuo, 2021, Zaitzevia tangliangi sp. nov. a new riffle beetle from China (Coleoptera: Elmidae Macronychini), pp. 591-596 in Zootaxa 5061 (3) on pages 592-596, DOI: 10.11646/zootaxa.5061.3.12, http://zenodo.org/record/564978