Comparative phylogeography of the Yellow River schizothoracine fishes (Cyprinidae): Vicariance, expansion, and recent coalescence in response to the Quaternary environmental upheaval in the Tibetan Plateau

May 1, 2009

A comparative phylogeographic assessment of all the Yellow River schizothoracine fishes revealed three main phylogenetic patterns: the three deeply subdivided lineages of the Gymnocypris species complex, the weak intraspecific subdivisions of Schizopygopsis pylzovi and Chuanchia labiosa, and the large-scale uniformity of Platypharodon extremus and Gymnodiptychus pachycheilus. These observations suggest that the boundaries of ancient basins in the head-water area of the Yellow River formed hydrological barriers to gene flow. We hypothesize that oscillating Quaternary geographical and climatic conditions in the Tibetan Plateau forced the repeated contraction, vicariance, and expansion of the distribution region and were followed by a very recent coalescence event. We infer that those greater ancient lake basins acted as Quaternary glacial refugia, while the historical vicariance and the Yellow River capture are largely responsible for the present-day spatial distribution of genetic variations within the Yellow River schizothoracine fishes.