A New Species of Plateau Pit Viper (Reptilia: Serpentes: Gloydius) from the Upper Lancang (=Mekong) Valley in the Hengduan Mountain Region, Tibet, China
The Plateau Pit Viper, Gloydius strauchi, from southwest and central China has long been considered a single, widespread species despite suspicion that it represents a potential complex of distinct evolutionary lineages. Although series of works were published on the G. strauchi species complex over the last 10 yr, species boundaries and diagnostic features of different members of the complex have remained poorly understood. Combining both morphological and genetic data, we re-evaluate taxonomic statuses of populations of G. strauchi in southwest China and describe the eastern Tibetan populations as a new species. The new species is most closely related to G. monticola phylogenetically, and it differs from all congeners by having a matte dorsal body scale texture, oval and robust head shape, distinct body ornamentation and coloration, and unique hemipene morphology. In addition, we provide the first updated diagnostic key to all recognized members of the G. strauchi species complex, and discuss ongoing taxonomic problems associated with cryptic diversity within the genus in China.Abstract
Distribution of the Gloydius strauchi complex in western China. The shaded area (light blue) represents the previously recognized distribution of G. strauchi (following Zhao et al., 1999 and Zhao, 2009). The blue rectangles represent G. strauchi: (1) type locality at Kangding, Sichuan Province; (2) Litang, Sichuan Province, China. The red stars indicate localities of the new species in Chamdo Prefecture, Tibet, China: (1) Chagyab (type locality); (2) Markam. Yellow triangles represent G. angusticeps: (1) Zoige County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China; (2) Hongyuan County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China. Remaining orange shapes indicate type localities of remaining recognized members of the G. strauchi complex, which include (from west to east on the map) G. rubromaculatus (hexagon): Qumarleb, Qinghai Province, China; G. monticola (pentagon): Lijiang, Yunnan Province, China; G. liupanensis (circle): Liupanshan, Ningxia Hui Autonomous Region, China; and G. qinlingensis (trapezoid): Taibai, Shaanxi Province, China.
Phylogenetic relationships among Gloydius congeners on the basis of maximum likelihood and Bayesian analyses of four mitochondrial loci (12S, 16S, Cyt b, and ND4). Both likelihood bootstrap and Bayesian posterior probability values are mapped on the maximum clade credibility topology from Bayesian analyses for all nodes (in such order respectively), except for the terminal nodes that unify multiple individuals of G. halys and G. intermedius, which are both well supported (100/1.00).
Holotype of Gloydius huangi sp. nov. in life (adult female, KIZ 027654). (A) Dorsolateral, (B) dorsal (showing coloration of tongue), (C) body close-up, and (D) dorsal head close-up views.
Comparisons among types or topotypic individuals of members of the Gloydius strauchi complex in life. (A) Gloydius huangi sp. nov. (holotype), (B) G. strauchi (topotype), (C) G. monticola (topotype), (D) G. robromaculatus (holotype), (E) G. qinlingensis (topotype), and (F) G. liupanensis (topotype). Photos by Yufan Wang, Gernot Vogel, Bo Tan, and Hongman Chen.
Comparisons of dorsal body (1), lateral head (2), dorsal head (3), ventral head (4), and dorsal body close-up (5) among (A) Gloydius huangi sp. nov., holotype KIZ 027654, (B) G. strauchi, CIB 14359, (C) G. monticola CIB 72551, (D) G. rubromaculatus IOZ 032317, and (E) G. angusticeps holotype IVPP OV2634 in preservative.
Comparisons of hemipenes of Gloydius huangi sp. nov. KIZ 027666 (A) and G. rubromaculatus IOZ 032317 (B). Photo of G. rubromaculatus is taken from Shi et al. (2017).
Macro- (1) and microhabitats (2) of Gloydius huangi sp. nov. at (A) Jinduo, Chamdo Prefecture, Tibet, China and (B) Tongsha, Markam Prefecture, Tibet, China. Red arrows indicate the relative locations of the Lancang (=Mekong) River.
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