Molecular phylogeny of Asian freshwater and marine stingrays based on the DNA nucleotide and deduced amino acid sequences of the cytochrome b gene

To elucidate the phylogenetic relationship among stingrays of three freshwa ter and five marine species of the genera Himantura, Dasyatis, and Pastinac hus, belonging to the family Dasyatidae distributed in Thailand, Laos, Indi a, and Japan, we determined the nucleotide sequences of the mitochondrial D NA region encoding cytochrome b. Using two rayfish species belonging to the superfamily Myliobatoidea as out-groups, we found three clades for the col lected stingrays in the family Dasyatidae from anlayses using the neighbor- joining, maximum parsimony, and maximum likelihood algorithms. While specie s belonging to the genus Himantura formed one group, Dasyatis laosensis and Dasyatis sp. formed another group. The results obtained failed to show cle ar phylogenetic relationships of the genus Pastinachus with the genera Dasy atis and Himantura, since the corresponding bootstrap resampling values wer e 72, 55, and 65 in the neighbor-joining, maximum parsimony, and maximum li kelihood trees, respectively.