A molecular phylogeny of the Persian Gulf and the Gulf of Oman oyster species

Abstract

Abstract The taxonomy of oysters along the northern coasts of the Persian Gulf and the Gulf of Oman is not well recognized. We present a phylogenetic analysis of oyster species in these regions. We combined morphological and molecular techniques to obtain the identity of oysters to the lowest taxonomic levels. Analysis of partial nucleotide sequences from mitochondrial cytochrome c oxidase subunit I (COI) was used for the phylogenetic evaluation. Based on our findings, Iranian samples nested within the genus Saccostrea and belonged to Saccostrea mordax and Saccostrea palmula clades. The shell morphology of the studied samples was variable, as in other rock oyster species. The examination of morphological features was in line with the molecular outcomes, but despite some similarities, Iranian S. palmula had well-developed and elongated chomata. The results also showed that S. mordax and S. palmula possessed significant relative abundance as dominant oysters in the Persian Gulf and the Gulf of Oman, respectively. Phylogenetic analysis revealed that Iranian samples of S. palmula formed a separate subclade from the Gulf of California and Panama samples, with large genetic distances (6–7%). Iranian specimens differed morphologically and genetically, suggesting that they could be a new species, although more research is needed.