Diversity and Distribution of Fiddler Crabs (Crustacea: Brachyura: Ocypodidae) around the Arabian Sea.

Nine species of fiddler crabs (Crustacea: Ocypodidae: Gelasiminae) are known from the Arabian Sea and adjacent waters (Red Sea, Gulf of Aden, Gulf of Oman and Arabian/Persian Gulf): five species of , one , two and one . sequence data match morphological species boundaries and shows high connectivity within each. The fauna is highly endemic, with three species of (, and ) confined to this region, and four others restricted to the Indian Ocean. restricted to the Indian Ocean. and speciated locally and now have narrowly overlapping ranges in Oman. Our results confirm the westernmost distributions of and are Pakistan and the Red Sea, respectively. A key for the nine species is also provided to help identification.