The balanid barnacle, Amphibalanus amphitrite, is known as one of the most common fouling species in the world. A phylogenetic study using material from around the world recovered three distinct clades for this species. Material from the Persian Gulf (PG) and the Gulf of Oman (GO) were not included in that survey. In the present study, we aimed to assess the genetic diversity of the balanid barnacles of these two gulfs and to evaluate their phylogeography. In total, 94 COI DNA sequences were obtained from the PG and the GO material. Most of these sequences clustered into a single clade, corresponding to clade I of the previous global study. However, two sequences, one from the PG and one from the GO, fell into a separate clade corresponding to clade III of the previous study. These two gulfs share some common haplotypes, but host several unique ones that are separated from the most common haplotype mainly by a single mutation. Based on various indices, the genetic diversity of the PG material was higher than that of the GO. Low values of ΦST show a regular gene flow among the stations and the two gulfs. The Bayesian skyline plots and the mismatch distribution analyses both showed signs of a recent population expansion in the PG and the GO. We also modeled the potential distribution areas for A. amphitrite to reveal the separate suitable habitats for the clades. The current phylogeographic status and genetic diversity of A. amphitrite in the PG and GO appears to have been shaped by both historical events and recent human activities.
Keywords: Amphibalanus amphitrite; Barnacle; Gene flow; Phylogeography; Population Genetic.