Phylogeography And Speciation Of Genera Rhinogobio And Pseudogobio In China

The bottom dwelling Rhinogobio and Pseudogobio belonging to Gobioninae, Cyprinidae, Cypriniformes, are endemic to East Asian. In the present study, based on molecular data, morphological characters and distribution information, the phylogenetic relationships and speciation process of Rhinogobio and Pseudogobio were analyzed respectively, which lead to the following results.1. The cytochrome b (cyt b) gene in 55 specimens representing 4 species of Rhinogobio and the S7 ribosomal protein gene in 13 specimens, representing 3 species of Rhinogobio were analyzed. The phylogenetic relationships were constructed using neighbor-joining, maximum parsimony, and bayesian methods. Trees resulted from three analyses are almost the same topology. The average pairwise distances of cyt b gene (1140bp) among Rhinogobio was 4.13%—12.15%. The divergent time among these four species were 6.05- 2.06 million years ago (mya). The average pairwise distances of the S7 ribosomal protein gene (579bp) among Rhinogobio was 2.08%—3.78%. Combining the molecular data and morphological characters, we concluded that R. typus, R. cylindricus, R. hunanensis and R.ventralis are four vaild species, the speciation of R. typus and R. cylindricus are in paraphyletic stage and not completed.2. The cyt b gene in 61 specimens representing Pseudogobio was analyzed. The average pairwise distances of cyt b gene (1140bp) were 0.09%-11.95% among 45 haplotypes. Based on cyt b sequences, the phylogenetic relationships were constructed using neighbour-joining, maximum parsimony, and bayesian methods. Three analyses yielded almost the same topology, indicating that there exist five branches. They are Changjiang1, Zhujiang, Hainan, Changjiang2, Liaohe. The analysis based on the molecular clock principle indicated that the pattern formed 5.16 to 3.00 mya. Phylogenetic analyses suggested that there exist different genetic units, corresponding to different ecotype or geotypes, however, we propose that they belong a single species due to their weak morphological difference.3. We compared the speciation between Rhinogobio and Pseudogobio in three aspects and concluded that Rhinogobio species are more active than Pseudogobio species.