Molecular systematics of two enigmatic fishes in the genus Schizopygopsis in the Qinghai-Tibetan Plateau
QI De-Lin, GUO Song-Chang, ZHAO Xin-Quan* Northwest Plateau Institute of Biology, Chinese Academy of Science, Xining 810001, China
The genus Schizopygopsis(Steindachner)is widely distributed in the upper reaches of almost all the main rivers and lakes in the Qinghai-Tibetan Plateau. The wide distribution range and the peculiar ecological specializations of these fishes are of biological interest. The Schizopygopsis, therefore, is an ideal model with which to investigate the speciation, diversification and evolution of freshwater fish endemic to the Qinghai-Tibetan Plateau. Although special attention was given to the biology of the genus Schizopygopsis in the past, the taxonomy of Sp.malacanthus chengi(Fang)and Sp.anteroventris(Wu, Tsao, Zhu and Chen) remain controversial owing to their morphological similarity(for example, arrangement of pharyngeal teeth, sheath morphology of the lower jaw, character state of the pharyngeal bone, and gill rakers). In the present study, the complete sequences of the mitochondrial Cyt b gene from seventeen individuals represented Sp.malacanthus chengi, Sp.anteroventris and other five species of Schizopygopsis as well as five closed species in the same subfamily Schizothoracinae were sequenced. The sequences were subjected to maximum parsimony(MP), maximum likelihood(ML)and Bayesian analyses. The molecular phylogenetic analyses showed that Sp.malacanthus chengi and Sp.malacanthus didn’t cluster together and there was a relatively high(2.06%)divergence between them. Sp.anteroventris was placed in a clade genetically distant from the other species of Schizopygopsis. Results from the molecular data, coupled with other morphological characters suggest that Sp.malacanthus chengi should be elevated to specific status, keeping the species name of Sp.chengi, while Sp.anteroventris should be retained as a distinct species in the genus Schizopygopsis.