Abstract: The molecular phylogeny of seven species of the bidentatiformis group in the genus Neopsylla was studied based on the mutation of 16s rRNA gene in mitochondrial genome. The results showed that the interspecies mutation rate of five species (N.bidentatiformis, N. mana, N. pleski, N. teratura and N. hongyangensis) was 1%, the same as the intraspecies mutation, suggesting that the relations among these species are closer; while the mutation rate of N.abagatui is 4%, suggesting the long diversity history of N.abagatui. Four samples of N. bidentatiformis from two localities showed two genotypes, one of which was also found in N. hongyangensis. As suggested also by the morphological character, N. hongyangensis should not be classified to the setosa group. Whether N. hongyangensis and N. bidentatiformis are the same species needs further study. N. siboi showed unexpected large mutation rate (20%) compared with morphologically related species N. teratura, and the reason for this is not clear.

Key words: Neopsylla, bidentatiformis group, 16s rRNA, molecular phylogeny