Species status of Chinese Pinctada fucata, Japanese P. fucata martensii and Australian P. imbricata using ITS and AFLP markers

Species status for Chinese Pinctada fucata, Japanese P. fucata martensii and Australian P. imbricata was investigated using ITSs and AFLP. The results indicated that genetic differentiation among populations of the three nominal species is low, and intraspecific and interspecific genetic distances are overlapping, as revealed by ITSs and AFLP markers. Based on AFLP data, phylogenetic analysis showed that most individuals from P. imbricata population are clustered together, consistent with the result from principal component analysis. It was found that the three nominal species are genetically isolated by geographic distance. AMOVA indicated that no more than 6% of the total variation is attributed to interspecific differences. These observations support the hypothesis that the three species are conspecific. According to the priority rule of nomination, the correct name of the species should be P. fucata because Atlantic P. imbricata is reported to be genetically different from Australian P. imbricata.