Intertidal calcareous tubeworms (Annelida: Serpulidae) of the Persian Gulf and Gulf of Oman

The Serpulidae is a large family of sedentary polychaete annelids characterized by calcareous tubes. This family includes species of significant economic and ecological relevance due to their fouling ability. This study presents the first comprehensive taxonomic survey of the serpulid fauna in the Persian Gulf and Gulf of Oman. Sampling was conducted on the rocky shores of the Iranian coasts of the both gulfs from 2016 to 2020. In total, 17 species from seven genera were identified from intertidal and shallow subtidal areas. The genus Hydroides was the most speciose, with seven species, followed by Spirobranchus with four, Serpula with two, and Crucigera, Protula, Spiraserpula and Vermiliopsis, each with one. The study reports the genus Spiraserpula, H. albiceps and Spirobranchus aloni in the gulfs for the first time. Additionally, the presence of C. tricornis and Spirobranchus cf. polytrema that had been reported, formally confirmed herein. The species of Serpula and Spiraserpula are likely undescribed. For each taxon, morphological characteristics with illustrations, habitat and regional distribution are provided. We also suggest incorporating molecular data in future studies to resolve taxonomic uncertainties arising from interspecific variability and morphological similarities within serpulids. A regional identification key to the known shallow-water serpulids is provided.