Phylogeography of freshwater fishes of the Qilian Mountains area (Triplophysa leptosoma, Cobitidae: Cypriniformes)

Abstract

The effects of the physical environment on populations of organisms endemic to the Tibetan Plateau and its surrounding areas have attracted increased scientific interest in recent years. Triplophysa leptosoma (Cobitidae: Cypriniformes) is an endemic species restricted to the Tibet Plateau and adjacent areas. Its distribution includes river systems around the Qilian mountains areas which located in the northeast edge of Tibet Plateau, including the Shiyang River, Heihe River and Shule River in the Hexi Corridor, Qaidam Basin river system and Yellow River system. In this study, we use mitochondrial DNA sequences (cytochrome b gene 1000 bp and cytochrome oxidase I gene 635 bp) to investigate the effects of geomorphological changes associated with the uplift of the Qilian Mountains on the major patterns of intraspecific diversification and population structure of the T. leptosoma. Based on our data, phylogenetic relationships among the 48 haplotypes revealed five major clades with strong geographic orientation. Our results suggest that the origin of these clades may correspond to the intermittent uprise of the Qilian Mountains. The Quaternary climatic changes and glacial-interglacial cycles had an important effect on the differentiation of haplotypes and the genetic diversity of the T. leptosoma. Meanwhile, population expansion also occurred during the repeated glacial event and the basin interconnections in the past.