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Lycodon gammiei (Blanford, 1878), a rarely encountered species of Asian snake, is characterized by ambiguous systematics and biology. Based on a sole specimen of L. gammiei rediscovered in southeastern Xizang, China, we conduct a detailed morphological examination and description, and investigate the systematic position of this species. Morphologically, the newly collected specimen is closely aligned with specimens previously described. Mitochondrial DNA-based phylogenetic analyses reveal that L. gammiei constitutes an independent evolutionary lineage, forming a clade with L. fasciatus (Anderson, 1879), L. gongshan Vogel & Luo, 2011, L. butleri Boulenger, 1900, and L. cavernicolus Grismer, Quah, Anuar, Muin, Wood & Nor, 2014. The closest genetic distance between L. gammiei and its congeners was 10.2%. The discovery of L. gammiei in Medog County, China, signifies an eastward expansion of its known geographical distribution. [ABSTRACT FROM AUTHOR]

Snakes of the natricid genus Trachischium Günther, 1858 are distributed in the southern Himalayas. Due to their secretive nature and fossorial habits, their taxonomy, evolution, and ecology remain poorly understood. Based on a multilocus molecular phylogeny and morphological comparisons we explored Trachischium systematics. Results indicated that all representatives of Trachischium form a strongly supported clade with their close relatives in Blythia, and that Blythia is nested within Trachischium. Therefore, we suggest that Blythia is synonymous with Trachischium. Molecular data and morphological comparisons revealed cryptic diversity within Trachischium, and thus we describe one new species from China while also excluding T. guentheri and T. tenuiceps from the Chinese fauna. [ABSTRACT FROM AUTHOR]

Aim To investigate the population history and demographics of Jerdon's pitviper, Protobothrops jerdonii, and elucidate how the unique physical conditions and heterogeneous mountain environments resulting from the uplift of the Tibetan Plateau shaped the genetic diversity and evolutionary history of the species. Location China and Vietnam. Methods We sequenced and analysed a total of 1752 base pairs from two mitochondrial genes, cytochrome b (cyt b) and NADH dehydrogenase subunit (ND4), for 81 specimens sampled from 27 localities across the species' range, and a total of 464 base pairs from two nuclear genes for 28 representative samples from all mitochondrial DNA lineages. Based on these data, we constructed the genealogical relationships and estimated the divergence times of the mitochondrial DNA clades. Results The mitochondrial DNA results revealed the existence of five distinct, strongly supported and geographically structured DNA lineages within populations of P. jerdonii that are paraphyletic with respect to Protobothrops xiangchengensis. Estimation of divergence dates suggested that P. jerdonii possibly evolved in the western Hengduan Mountains region c. 6.6 Ma in the late Miocene. Nuclear DNA data did not provide sufficient resolution to distinguish the mitochondrial DNA lineages. Main conclusions Based on the present-day distribution and intraspecific genealogy, the evolutionary history of P. jerdonii can be explained by a pattern of dispersal followed by vicariance. All lines of evidence suggest that historical biogeographical factors, particularly the north-south orientation of the higher mountains, as well as low-elevation areas in western China, had the greatest influence on the population structure, lineage formation and species distribution of this snake. However, highly heterogeneous habitats and glacial cycles appear to have affected patterns of intraspecific differentiation. While our mitochondrial data provide evidence for clear phylogeographical structure, our small sampling of nuclear genes does not, suggesting that nuclear markers may not have had sufficient time to coalesce to match patterns observed in the mitochondrial data. [ABSTRACT FROM AUTHOR]