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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]

The elucidation of species diversity and distribution is critical within the fields of evolution, genetics, and conservation. The genus Sibynophis contains rare snakes that have historically received little attention. In this study, we conducted comprehensive sampling and use both mitochondrial and nuclear genetic markers to explore Sibynophis species diversity within China. Our findings revealed that S. c. miyiensis should be considered synonymous with S. c. grahami, and S. c. grahami should be gave a specific rank as S. grahami. In addition, we discovered S. triangularis was new to China and Myanmar. Based on the specimens and molecular phylogeny results, we redefined the species distribution boundaries of each Chinese species. [ABSTRACT FROM AUTHOR]

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Abstract: Based on a combination of six mitochondrial gene fragments (12S RNA, cyt b, ND1, ND2, ND4 and CO1) and one nuclear gene (c-mos) from 22 genera we infer phylogenetic relationships among natricine snakes and examine the date and area of origin of these snakes. Our phylogenetic results indicate: (1) the subfamily Natricinae is strongly supported as monophyletic including a majority of extant genera, and a poorly known and previously unassigned species Trachischium monticola, (2) two main clades are inferred within Natricinae, one containing solely taxa from the Old World (OW) and the other comprising taxa from a monophyletic New World (NW) group with a small number of OW relatives. Within the first clade, the genera Xenochrophis and Amphiesma are apparently not monophyletic. Divergence dating and ancestral area estimation indicate that the natricines originated in tropical Asia during the later Eocene or the Oligocene. We recover two major dispersals events out of Asia, the first to Africa in the Oligocene (28Ma) and the second to the Western Palearctic and the New World at 27Ma. This date is consistent with the dispersal of numerous other OW groups into the NW. [Copyright &y& Elsevier]

• The monophyly of Trimerodytes is strongly supported, with T. yapingi as the basal to the remaining species. • Trimerodytes likely originated in Hengduan Mountains (eastern Tibetan Plateau) in western China at 23.93 Ma (17.09–31.30). • The validity of T. yunnanensis is supported. The Asian water snake genus Trimerodytes (formerly Sinonatrix) is endemic to East and Southeast Asia. Although several species have been included in various phylogenetic studies previously, the evolution and relationships among members of this genus as a whole remain unexplored. In this study, we report the sequencing two protein-coding mitochondrial gene fragments (MTCYB and ND2) and three nuclear genes (c-mos , NT3 , and Rag1), reconstruct interspecific phylogeny, and explore biogeography for the genus Trimerodytes. Both Bayesian inference and maximum likelihood analyses consistently recover the monophyly of Trimerodytes with strong support, with T. yapingi the sister-group to the remaining species. The divergence date and ancestral area estimation suggest that Trimerodytes likely originated in Hengduan Mountains (eastern Tibetan Plateau) in western China at 23.93 Ma (95% HPD: 17.09–31.30), and intraspecific divergence began at about 4.23 Ma (95% HPD: 2.74–6.10). Analyses support the validity of T. yunnanensis. [ABSTRACT FROM AUTHOR]

[Display omitted] • All species of Rhabdophis nuchalis (sensu lato) complex did not form a monophyly, but each species was highly supported. • Incongruence was detected between nuclear and mtDNA phylogeny. • A new taxa has been described from southwestern China. • Geographic distribution boundary for each species within this species complex has been redefined. Stable taxonomy and robust phylogeny are essential for the evolution and conservation of organisms. The Rhabdophis nuchalis (sensu lato) complex presently contains three species (R. nuchalis , R. chiwen , R. pentasupralabialis). Although several studies have explored the diversity and phylogeography of this group, certain issues related to systematics and taxonomy remain unresolved. Here, based on genome-wide data, including single nucleotide polymorphisms (SNPs) generated from ddRAD-seq and mitochondrial DNA (mtDNA), we re-evaluated the phylogenetic relationships and cryptic diversity of this species group. Our results are generally consistent with previous studies but provide some new insights. Phylogenetic relationship reconstruction based on SNPs and mtDNA revealed that three species in the R. nuchalis (sensu lato) complex did not form a monophyly but each species is well supported as monophyletic lineage in SNP-based analyses. Population structure analyses showed genetic admixture between several species pairs. Additionally, the population in eastern Yunnan, China, was identified as a potential cryptic species and thus described as a new species based on morphological data. From our results and previous studies, we redefined the distribution boundary for each species in the R. nuchalis (sensu lato) species complex. [ABSTRACT FROM AUTHOR]