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| [A-B] Pareas boulengeri (Angel, 1920); [C-D] Pareas dabieshanensis Zhang, Pan & Zhang; [E-F]. P. orientalis Zhang, Pan & Zhang, in C.-W. Zhang, Xu, Luo, Liu, Yu, Zhou, Pan et B.-W. Zhang, 2025. |
Abstract
The Boulenger’s slug snake (Pareas boulengeri Angel, 1920) has previously been documented as relatively widely distributed across the eastern, southern, and southwestern regions of China. In the present study, integrated morphological comparisons and molecular phylogenetic analyses were undertaken to reevaluate the taxonomic status of P. boulengeri and to describe two new species: Pareas dabieshanensis sp. nov. and Pareas orientalis sp. nov. Phylogenetic reconstruction based on CYTB gene sequences indicated that populations previously identified as P. boulengeri comprise three distinct lineages: true P. boulengeri, P. dabieshanensis sp. nov., and P. orientalis sp. nov. The two new species exhibit significant genetic divergence from their congeners, with uncorrected pairwise distances of 4.1–4.5%, consistent with interspecific divergence within the genus. Morphologically, P. dabieshanensis sp. nov. is distinguished by the presence of two subocular scales, the absence of preocular scales, and higher ventral (184–187) and subcaudal (68–74) counts. P. orientalis sp. nov. is characterized by a single preocular scale and fused subocular and postocular scales. The revised distributions restrict P. boulengeri to southwestern China, while the new species are confined to the Dabie Mountains (Anhui, Hubei, Henan) and eastern China (southern Anhui, Jiangsu, Jiangxi, Zhejiang), respectively. The non-overlapping ranges of P. dabieshanensis sp. nov. and P. orientalis sp. nov., bisected by the Yangtze River, suggest that this major hydrological system acted as a biogeographic barrier driving speciation. This study expands the genus Pareas to 33 recognized species (27 in China) and underscores the prevalence of cryptic diversity within morphologically conserved lineages.
Key Words: Cryptic species, geographic isolation, molecular phylogeny, morphology, speciation, Yangtze River
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| Comparative analysis of head scaling. Specimens include. A. Pareas boulengeri (LPSSC2024070502); B. A living specimen (GZNU2018052302); C. The holotype of P. dabieshanensis sp. nov. (AHU2024051501); D. A living specimen (AHU2021050201); E. The holotype of P. orientalis sp. nov. (AHU2024051501); and F. A living specimen (AHU2024051502). Photos by Cai-wen Zhang, Shan Shen, and Tao Luo. |
Pareas boulengeri (Angel, 1920)
Pareas dabieshanensis Zhang, Pan & Zhang, sp. nov.
Etymology. Pareas dabieshanensis sp. nov. refers to the distribution of the new species in the Dabie Mountains. We recommend designating this new species Dabie Mountains Slug-eating Snake and 大别山钝头蛇 (Dà Bié Shān Dùn Tóu Shé).
Pareas orientalis Zhang, Pan & Zhang, sp. nov.
Etymology. Pareas orientalis sp. nov. refers to the new species in eastern China. We recommend designating this new species the Eastern China slug-eating snake and 华东钝头蛇 (Huá Dōng Dùn Tóu Shé).
Cai-wen Zhang, Shi-hang Xu, Tao Luo, Chong Liu, Lei Yu, Jiang Zhou, Tao Pan and Bao-wei Zhang. 2025. Taxonomic and Distributional Revision of Pareas boulengeri (Reptilia, Squamata, Pareidae), including Two New Species from eastern and central China. Zoosystematics and Evolution. 101(4): 1621-1638. DOI: doi.org/10.3897/zse.101.156697
