S. Amiri - Marine Biology Group, Marine Science and Technology Department, Islamic Azad University Science and Research Branch, Tehran, Iran.
P. Ghavam Mostafavi - Marine Biology Group, Marine Science and Technology Department, Islamic Azad University Science and Research Branch, Tehran, Iran.
M.B. Nabavi - Marine Biology Group, Oceanic and Marine Science Department, Khorramshahr Marine Science and Technology University, Khorramshahr, Iran
M.H. Shahhosseini - Islamic Azad University Shar-e-Qods Branch, Qods, Iran.

Although polychaetes are the most abundant organisms in marine ecosystems, still their genetic diversity is understood inadequately. In this study, molecular identification of Nereididae polychaetes was performed by sequencing a segment of mitochondrial COI gene, isolated from mitochondrial DNA, and comparing nucleotide divergence, Molecular taxonomy, interspecific and intraspecific relations of Nereid species among ۴ intertidal stations assigned in Persian Gulf of Iran. Analysis of ۱۰۹ identified specimens, revealed ۷۸ provisional gene sequences, related to ۹ species and ۶ genera, in which interspecific divergence was ۱.۴ times higher than intraspecific divergence (۲.۸۲% versus ۱.۹۵%). The average pairwise sequence divergence for all sequences was estimated at ۱.۳۷%. In three cases maximum divergence within a lineage exceeded the minimum nearest-neighbor distance: Perinereis sp., Platynereis sp. and Platynereis bicanaliculata. Maximum species similarity was observed amongst ۳ sampling sites assigned in Bushehr Province whilst Bandar Abbas`s specimens showed less similarity to Bushehr station. Out of the ۱۰۹ COI gene sequences of Nereididae polychaetes in this study, ۳۴ contained multiple lineages. These results support the assertion that many Nereid populations in the Persian Gulf previously thought of as a single species, actually consist of two or more divergent lineages.

Polychaetes, Nereididae, COI, Barcoding, Persian Gulf