Article · Wikipedia archive · Last revised Jun 15, 2026

Achalinus

Achalinus is a genus of harmless snakes in the family Xenodermidae. Species of the genus are found in China, Japan, Taiwan, and northern Vietnam. Ten species are recognized as being valid. Achalinus was previously placed in Colubridae. The nickname "odd-scaled" is because their dorsal scales do not overlap one another as in most snakes, but instead are spread out and lie individually similar to pieces of a puzzle. Odd-scaled snakes are burrowers that crawl below the fallen leaves of the forest.

Last revised
Jun 15, 2026
Read time
≈ 4 min
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902 w
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Achalinus
Formosa odd-scaled snake, Achalinus f. formosanus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Xenodermidae
Genus: Achalinus
W. Peters, 18691

Achalinus (common name: odd-scaled snakes)2 is a genus of harmless snakes in the family Xenodermidae. Species of the genus are found in China, Japan, Taiwan, and northern Vietnam. Ten species are recognized as being valid.13 Achalinus was previously placed in Colubridae (along with other xenodermids).4 The nickname "odd-scaled" is because their dorsal scales do not overlap one another as in most snakes, but instead are spread out and lie individually similar to pieces of a puzzle. Odd-scaled snakes are burrowers that crawl below the fallen leaves of the forest.

Species

Image Species3 Taxon author3 Subsp.*3 Common name3 Geographic range13
A. ater Bourret, 1937 0 Bourret's odd-scaled snake Northern Vietnam and China in Guizhou and Guangxi
A. dabieshanensis C. Zhang, Liu, R. Huang & B. Zhang, 2023 0 Dabie Mountains odd-scaled snake China
A. damingensis Y. Xu, Yang, J. Wu, Gong, R. Huang & S. Huang, 2023 0 China (Guangxi)
A. dehuaensis K. Li, Y. Wu, R. Xu, Zhu, Ren, Guo & Dong, 2021 0 Dehua odd-scaled snake China
A. emilyae Ziegler, T.Q. Nguyen, C. Pham, T.Th. Nguyen, A. Pham, van Schingen, Th.Th. Nguyen & Le, 2019 0 Emily's burrowing snake Vietnam
Achalinus formosanus formosanus A. formosanus Boulenger, 1908 1 Formosa odd-scaled snake Taiwan and Japan in the southern Ryukyu Islands
A. hainanus C. Huang, 1975 0 Hainan odd-scaled snake China on Hainan island
A. huangjietangi R. Huang, Peng & S. Huang, 2021 0 Huang's odd-scaled snake Huangshan City, Anhui Province, China
Achalinus hunanensis A. hunanensis S. Ma, Shi, Xiang, Shu & J. Jiang, 2023 Hunan odd-scaled snake Hunan Province, China
Achalinus jinggangensis A. jinggangensis (Zong & J. Ma, 1983) 0 Zong's odd-scaled snake China in Jiangxi
A. juliani Ziegler, T.Q. Nguyen, C. Pham, T.Th. Nguyen, A. Pham, van Schingen, Th.Th. Nguyen & Le, 2019 0 Julian's burrowing snake Vietnam
A. meiguensis Hu & Zhao, 1966 0 Szechwan odd-scaled snake China in western Sichuan at elevations of 1200–1400 m
A. mirabilis Xu et al., 2026 5 0 Kuocang Mountain Odd-scaled Snake China
A. niger Maki, 1931 0 Black odd-scaled snake Taiwan
A. ningshanensis Yang, R. Huang, K. Jiang, Burbrink & S. Huang, 2022 0 Ningshan odd-scaled snake China
A. panzhihuaensis Hou, K. Wang, Guo, Chen, Yuan & Che, 2021 0 Panzhihua odd-scaled snake China
A. pingbianensis K. Li, Yu, Y. Wu, Liao, K. Tang, Liu & Guo, 2020 0 Pingbian odd-scaled snake China
Achalinus rufescens A. rufescens Boulenger, 1888 0 Boulenger's odd-scaled snake Northern Vietnam and China in Hong Kong, Hainan and west to Guizhou, Shaanxi, Guangdong and Fujian
A. sheni S. Ma, Xu, Qi, Y. Wang, S. Tang, Huang & J. Jiang, 2023 0 Shen's odd-scaled snake Hunan Province, China
A. spinalis W. Peters, 1869 0 Peters' odd-scaled snake Northern Vietnam, Japan (Kyūshū, Honshū, the Ryukyu Islands, Koshiki, Tokuno-shima: Kametoku and Inokawa), and central China (east to Fujian, west to Yunnan and Sichuan, and north to Gansu and Shaanxi. Also in Zhejiang, Jiangxi, Jiangsu and Hubei) at an elevation of 1,230 m
A. timi Ziegler, T.Q. Nguyen, C. Pham, T.Th. Nguyen, A. Pham, van Schingen, Th.Th. Nguyen & Le, 2019 0 Tim's burrowing snake Vietnam
Achalinus tranganensis A. tranganensis6 Luu, Ziegler, Ha, Lo, Hoang, Ngo, Le, Tran & T.Q. Nguyen, 2020 0 Vietnam: Ninh Binh province
A. vanhoensis Ha, Ziegler, Sy, Le, T.Q. Nguyen & Luu, 2022 0 Vietnam
Achalinus werneri A. werneri Van Denburgh, 1912 0 Amami odd-scaled snake Japan in the central Ryukyu Islands
A. yangdatongi Hou, K. Wang, Guo, Chen, Yuan & Che, 2021 0 Yang's odd-scaled snake China
A. yunkaiensis J. Wang, Y. Li & Y. Wang, 2019 0 Yunkai Mountain's odd-scaled snake, Yunkai Mountain's burrowing snake China
A. zugorum Miller, Davis, Luong, Do, C. Pham, Ziegler, Lee, de Queiroz, Reynolds & T.Q. Nguyen, 2020 0 Zug's odd-scaled snake 7 Northern Vietnam

*) Not including the nominate subspecies.

Nota bene: A taxon author (binomial authority) in parentheses indicates that the species was originally described in a genus other than Achalinus.

References

References

  1. Wallach, Van; Williams, Kenneth L.; Boundy, Jeff (2014). Snakes of the World: A Catalogue of Living and Extinct Species. Boca Raton, Florida: CRC Press. pp. 5–6. ISBN 978-1-4822-0848-1.
  2. Durso, Andrew (2016). "Dragonsnakes and Filesnakes Revisited". Life is Short, but Snakes are Long. Retrieved 27 February 2016.
  3. Achalinus at the Reptarium.cz Reptile Database. Accessed 27 February 2016.
  4. Durso, Andrew (2013). "Basics of Snake Taxonomy". Life is Short, but Snakes are Long. Retrieved 27 February 2016.
  5. Xu, Yu-Hao; Hu, Jia-Hao; Qi, Shuo; Ma, Shun; Chen, Hao-Jun; Zhang, Tie-Rui; Zhang, Yun-Fei; Sun, Fan-Yue; Zhou, Jia-Jun; Xu, Jin-An; Wang, Ying-Yong; Peng, Li-Fang (2026). "Taxonomic reassessment of Achalinus jinggangensis (Zong & Ma, 1983) (Serpentes, Xenodermidae), with description of a new species from Zhejiang Province, China". Zoosystematics and Evolution. 102 (2): 387–409. Bibcode:2026ZooEv.102..387X. doi:10.3897/zse.102.183453.
  6. Luu, Vinh Quang; Ziegler, Thomas; Ha, Nghia Van; Lo, Oanh Van; Hoang, Tuoi Thi; Ngo, Hanh Thi; Le, Minh Duc; Tran, Dung Hoang; Nguyen, Truong Quang (2020). "A new species of Achalinus (Squamata: Xenodermidae) from Trang An Landscape Complex, Ninh Binh Province, Vietnam". Zootaxa. 4877 (1): 174–184. doi:10.11646/zootaxa.4877.1.8. ISSN 1175-5334. PMID 33311331. S2CID 228819391.
  7. Miller, Aryeh H.; Davis, Hayden R.; Luong, Anh Mai; Do, Quyen Hanh; Pham, Cuong The; Ziegler, Thomas; Lee, Justin L.; de Queiroz, Kevin; Reynolds, R. Graham; Nguyen, Truong Quang (2020). "Discovery of a New Species of Enigmatic Odd-Scaled Snake (Serpentes: Xenodermidae: Achalinus) from Ha Giang Province, Vietnam". Copeia. 108 (4). doi:10.1643/CH2020060. S2CID 230507219.