Phylogeography of the Highly Specialized Schizothoracine Fishes (Teleostei: Cyprinidae) in the Tibetan Plateau and Their Implications

The climatic oscillations in the Quaternary play a key role in shaping phylogeographical pattern and demographic history of species. The Tibetan Plateau, the largest and highest plateau on earth, provides an insight upon understanding the significance of the impact of the paleogeographical events and climatic shifts on the distribution pattern and evolution of the biota. Here, we use mitochondrial cytochrome b to infer the phylogeographical structures and demographic histories of seven highly specialized schizothoracine fishes in the central Tibetan Plateau. Based on a wide range sampling, comprising eighteen endorheic lakes and four exorheic river systems and 1200 individuals, we detected 149 haplotypes that were divided into three distinct clades by phylogenetic and network analyses, corresponding geographically to east Tibet (clade ET), west Tibet (clade WT) and central-southeast Tibet (clade CT). We highlighted tectonics and climate processes during the Quaternary have played an important role in shaping the genetic pattern and demography of fish populations in the central Tibetan Plateau, and support the climatic hypothesis that the glaciations and Asia monsoon generally trend diminishing since the middle Pleistocene.