The Arabian blackspot threadfin, Polydactylus mullani, is an endemic species of the Arabian Sea, occurring along the Indian and Pakistani coasts. Its presence is recorded here for the first time at the south-western end of the Gulf of Oman. It could be that P. mullani was confused until now with Polydactylus sextarius as, until 2001, the former species was regarded only as a subspecies of the latter. However, P. mullani is not mentioned in any work dealing with fish diversity in Oman since 2001. The number of species of Polynemidae known in Oman thus amounts today to three: Eleutheronema tetradactylum, P. mullani and P. plebeius.