Research Article |
|
Corresponding author: Xiang-Sheng Chen ( chenxs3218@163.com ) Academic editor: Felipe Barbosa
© 2025 Ri-Xin Jiang, Lin Yang, Jian-Kun Long, Zhi-Min Chang, Chuan-Liang Sun, Xiao Feng, Mao-Heng Du, Xiang-Sheng Chen.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jiang R-X, Yang L, Long J-K, Chang Z-M, Sun C-L, Feng X, Du M-H, Chen X-S (2025) Additional new species of the genus Zaitzevia (Coleoptera, Elmidae) from China with an updated key to species from mainland China. ZooKeys 1258: 199-212. https://doi.org/10.3897/zookeys.1258.169390
|
The riffle beetle genus Zaitzevia Champion, 1923 comprises 29 described species, distributed across Asia and North America. China exhibits particularly high species diversity within this genus, with 16 recorded species. In this study, we describe two new Zaitzevia species from China: Z. fodingshanus sp. nov. from Guizhou Province and Z. lipingae sp. nov. from Yunnan Province. Habitus and diagnostic features of the new species are illustrated, along with a checklist of all known Chinese Zaitzevia species, a key, and a distribution map of Zaitzevia species from mainland China. The comparative diagnoses discuss characters of the new and known species. The results show that the existing species diversity requires more detailed research acrosslarger areas of Southwest China in the future.
Aquatic beetle, checklist, China, Elmidae, identification key, Macronychini, new species, riffle beetle, taxonomy
The Macronychini genus Zaitzevia Champion, 1923 comprises 29 valid species, distributed across East, Southeast, and Central Asia as well as North America (
The Japanese fauna of Zaitzevia was recently reviewed (
As part of our ongoing aquatic beetle survey in Guizhou Province initiated in 2021, a series of new elmid beetles have been discovered and described (
The material examined during this work is deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC).
Collecting data on the specimens are quoted verbatim. The Chinese translation of each locality below the provincial level is included in parentheses at the first appearance in the text. Each type specimen bears the following label: ‘HOLOTYPE (red) (or PARATYPE (yellow)), ♂, Zaitzevia + specific name sp. nov., Jiang & Chen, 2025.
Habitus images were taken using a Canon 5D Mark IV digital camera with an MP-E 65 mm f/2.8 1–5× macro lens. A Godox MF12 flash was used as the light source. Images of the morphological details were taken either using a Canon 5D Mark IV digital camera in conjunction with a Mitutoyo Plan NIR 10 lens and a Godox MF12 flash, or with a Nikon SMZ25 stereoscopic microscope and a Nikon DS-Ri2 microscope camera. Zerene Stacker (v. 1.04) was used for image stacking. All images were improved and grouped into plates in Adobe Photoshop CS5 Extended.
Morphological terminology and the format for the descriptions follow
(4 ♂♂, 4 ♀♀): Holotype: China: • ♂, labeled ‘China: Guizhou, Tong ren City (铜仁市), Shiqian County (石阡县), Ganxi Township (甘溪乡), near Fuyan Village (扶堰村), Fodingshan National Nature Reserve (佛顶山国家级自然保护区), an unnamed stream, 27°20'56"N, 108°2'22"E; H: ~850 m, 15.07.2025, Ri-Xin Jiang leg.’ (GUGC). Paratypes: • 3 ♂♂, 4 ♀♀, with the same label data as the holotype (GUGC).
Male. Body elongately elliptical (Fig.
Head
(Fig.
Pronotum
(Fig.
Elytra
(Fig.
Mesothorax
(Fig.
Disc of ventrites I–IV and anteriorly middle of ventrite V shiny, covered with small, sparse punctures, without plastron setae; other areas of ventrites covered with plastron setae. Apical area of ventrite V granulated, apical margin distinctly emarginate at middle.
Legs simple, femora swollen, surface covered with plastron setae; inner side of distal halves of tibiae with cleaning fringes; tarsi slightly shorter than tibiae; tarsal claws simple and strong.
Aedeagus
(Fig.
Diagnostic features of Zaitzevia fodingshanus sp. nov., holotype. A. Aedeagus, ventral view; B. Ditto, lateral view; C. Ditto, dorsal view; D. Ditto, apex of median lobe, dorsal view; E. Ternite IX; F. Ovipositor; G, H. Apical part of ovipositor. Scale bars: 0.5 mm (A–C); 0.1 mm (D–G); 0.05 mm (H).
Measurements (N = 4): CL: 2.53–2.83 mm; HW: 0.47–0.51 mm; PL: 0.73–0.79 mm, PW: 0.83–0.87 mm; EL: 1.80–2.04 mm, EW: 1.13–1.18 mm.
Female: externally similar to the male, apex of sternite VIII rounded. Ovipositor as in Fig.
China: Guizhou Province.
All adults were collected from a small ravine stream (Fig.
The specific epithet refers to the type locality, Fodingshan National Nature Reserve; the name is treated as an adjective.
Zaitzevia fodingshanus sp. nov. is more or less similar to Z. tangliangi Jiang & Wang, 2021 from Hubei Province and Z. yingzuijieensis Jiang & Chen, 2023 from Hunan Province. All three species share a similar habitus, e.g., a smaller body size, and a shallow and short longitudinal impression of the pronotum. The new species can be easily distinguished from Z. tangliangi and Z. yingzuijieensis by the base of the pronotum with several pairs of small granules at middle (vs. with a pair of small foveae in the same position in Z. tangliangi and Z. yingzuijieensis) and the very different form of the aedeagus (aedeagus much slenderer and the anterior pair of sclerites much smaller in Z. tangliangi and Z. yingzuijieensis;
(3 ♂♂, 2 ♀♀): Holotype: China: • ♂, labeled ‘China: Yunnan, Bao’an City (保安市), Longyang District (隆阳区), Lujiang Town (潞江镇), near Nankang Village (赧亢村), an unnamed stream, 24°50'46"N, 98°45'38"E; H: ~2000 m, 30.07.2023, Ping Li & Lan Jia leg.’ (GUGC). • Paratypes: 2 ♂♂, 2 ♀♀, with the same label data as the holotype (GUGC).
Male. Large species, body elongately elliptical (Fig.
Diagnostic features of Zaitzevia lipingae sp. nov., paratype. A. Head, dorsal view; B. Pronotum, dorsal view; C. Elytra; D. Prosternal process and metaventrite; E. Abdomen, male, dorsal view; F. Ditto, lateral view; G. Abdomen, female, dorsal view; H. Ditto, lateral view. Scale bars: 1 mm (C, D); 0.5 mm (A, B, E–H), Note: red arrow of E–H, projection of ventrite IV.
Head
(Fig.
Pronotum
(Fig.
Elytra
(Fig.
Mesothorax
(Fig.
Disc of ventrites
I–IV and anteriorly middle of ventrite V shiny, covered with sparse small punctures, without plastron setae; other areas of ventrites covered with plastron setae. Posterior margin of ventrite IV (Fig.
Legs simple, femora swollen, surface covered with plastron setae; inner half of tibiae with cleaning fringes; tarsi slightly shorter than tibiae; tarsal claws simple.
Aedeagus
(Fig.
Measurements (N = 3): CL: 3.12–3.44 mm; HW: 0.58–0.62 mm; PL: 0.88–0.97 mm, PW: 0.98–1.05 mm; EL: 2.20–2.56 mm, EW: 1.31–1.46 mm.
Female: externally similar to the male, projection of ventrite IV (Fig.
China: Yunnan Province.
All adults were collected from a small ravine stream (Fig.
The specific epithet “lipingae” honors our friend and colleague Dr Ping Li (Guizhou University), one of the collectors of this new species.
Zaitzevia lipingae sp. nov. can be readily distinguished from all other known Zaitzevia species by the presence of a distinct projection on ventrite IV and the very long and slender aedeagus.
1. Zaitzevia acuta Bian & Hu, 2024 (Guangdong)
2. Zaitzevia babai Nomura, 1963 (Taiwan)
3. Zaitzevia chenzhitengi Jiang & Wang, 2020 (Sichuan, Shaanxi, Yunnan)
4. Zaitzevia fengtongzhaiensis Jiang & Chen, 2023 (Sichuan)
5. Zaitzevia fodingshanus Jiang & Chen sp. nov. (Guizhou)
6. Zaitzevia formosana Nomura, 1963 (Taiwan)
7. Zaitzevia gaoligongensis Bian & Zhang, 2022 (Yunnan)
8. Zaitzevia lipingae Jiang & Chen sp. nov. (Yunnan)
9. Zaitzevia muchenae Bian & Zhang, 2022 (Yunnan)
10. Zaitzevia nanlingensis Bian & Hu, 2024 (Guangdong, Hunan)
11. Zaitzevia parallela Nomura, 1963 (Taiwan)
12. Zaitzevia triangularis Peng, Bian & Wang, 2024 (Shanxi)
13. Zaitzevia reniformis Bian & Zhang, 2022 (Yunnan)
14. Zaitzevia sichuanensis Jiang & Chen, 2023 (Sichuan)
15. Zaitzevia tangliangi Jiang & Wang, 2021 (Hubei)
16. Zaitzevia tsushimana Nomura, 1963 (Jilin; Japan; Korea; Russia)
17. Zaitzevia xiongzichuni Jiang & Wang, 2020 (Yunnan)
18. Zaitzevia yingzuijieensis Jiang & Chen, 2023 (Hunan)
| 1 | Large species, CL > 3 mm | 2 |
| – | Smaller species, CL < 3 mm | 8 |
| 2 | Surface of elytra distinctly wrinkled; aedeagus short and strong, apex of median lobe of aedeagus characteristically arrowhead-like | Z. chenzhitengi |
| – | Surface of elytra shiny or only weakly wrinkled; aedeagus much slender | 3 |
| 3 | Posterior margin of ventrite IV with a small triangular projection at middle | Z. lipingae sp. nov. |
| – | Posterior margin of ventrite IV without projection | 4 |
| 4 | Surface of pronotum shiny | Z. xiongzichuni |
| – | Surface of pronotum coarse or weakly wrinkled | 5 |
| 5 | Median lobe of aedeagus curved at middle | Z. sichuanensis |
| – | Median lobe of aedeagus not curved at middle | 6 |
| 6 | Apex of median lobe of aedeagus widely triangular and strongly curved dorsally | Z. muchenae |
| – | Apex of median lobe of aedeagus not widely triangular, and not or weakly curved dorsally | 7 |
| 7 | Body larger, CL ≈ 3.5 mm, apex of median lobe of aedeagus acute | Z. fengtongzhaiensis |
| – | Body smaller, CL ≈ 3.0 mm, apex of median lobe of aedeagus blunt | Z. triangularis |
| 8 | Longitudinal impression of pronotum extends from base of pronotum | Z. tsushimana |
| – | Longitudinal impression of pronotum not contacted with base of pronotum | 9 |
| 9 | Longitudinal impression of pronotum long, longer than 1/2 length of pronotum | 10 |
| – | Longitudinal impression of pronotum short, less than 1/2 length of pronotum | 11 |
| 10 | Median lobe of aedeagus short, less than twice length of phallobase | Z. gaoligongensis |
| – | Median lobe of aedeagus long, longer than twice length of phallobase | Z. nanlingensis |
| 11 | Body length ≤ 2 mm | 12 |
| – | Body length > 2 mm | 13 |
| 12 | Median lobe of aedeagus strongly curved in lateral view, apex rounded | Z. reniformis |
| – | Median lobe of aedeagus weakly curved in lateral view, apex acute | Z. acuta |
| 13 | Sublateral carinae of pronotum long, about 1/2 length of pronotum, apical half distinctly curved | Z. fodingshanus sp. nov. |
| – | Sublateral carinae of pronotum short, about 1/3 length of pronotum, nearly straight | 14 |
| 14 | Disc of prosternal process wrinkled, apex of median lobe of aedeagus nearly symmetrical | Z. tangliangi |
| – | Disc of prosternal process shiny, apex of median lobe of aedeagus distinctly asymmetrical | Z. yingzuijieensis |
The authors express their sincere gratitude to Dr Ping Li and Miss Lan Jia (both Guizhou University, Guiyang, China) for their assistance in our investigative work. We also thank Drs Fedor Čiampor Jr (Slovak Academy of Sciences, Bratislava, Slovakia) and Maria Inês da Silva dos Passos (Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil) for reviewing this work. Dr Zhi-Teng Chen (Jiangsu University of Science and Technology, Zhenjiang, China) kindly revised the English of this work. Field work was supported by the Administrations of Fodingshan National Nature Reserve, Guizhou Province. Financial support was provided by the Program of Excellent Innovation Talents, Guizhou Province (No. 20154021), and the Program of Comprehensive Scientific Expedition of the Fodingshan National Nature Reserve in Guizhou (MCHC-DZ-ZC20255008).
The authors have declared that no competing interests exist.
No ethical statement was reported.
No use of AI was reported.
No funding was reported.
Ri-Xin Jiang wrote the manuscript; Jian-Kun Long and Zhi-Min Chang reviewed the manuscript; Lin Yang and Xiang-Sheng Chen guided and supported this work; Chuan-Liang Sun, Xiao Feng, and Mao-Heng Du participated in the field investigation and provided essential support for the collection of new species.
Zhi-Min Chang https://orcid.org/0000-0002-7247-9706
All of the data that support the findings of this study are available in the main text.