The genus Plectorhinchus (sweetlips) exhibits high morphological plasticity, especially in coral reef ecosystems, which is often due to response to different environments regardless of genotype. Few studies are known on the correct taxonomic identification of the species in the Persian Gulf and Gulf of Oman. In the present study, the morphometric and meristic differences between eight sweetlips from the Persian Gulf and the Gulf of Oman were investigated using traditional and geometric morphometrics. The traditional approach based on principal component analysis (PCA) and discriminant function analysis (DFA) showed significant morphological differences among morphotypes. The main features used to discriminate between morphotypes were body depth, orbital diameter, caudal peduncle depth, dorsal fin length, gill rakers, and transverse scale rows. The geometric morphometric method (GMM) gave almost congruent results with the traditional morphometric and showed a high divergence between species except for Plectorhinchus schotaf and P. flavomaculatus. The morphometric and shape variations could be related to ecomorphological variables. Species diversity was greater in the Gulf of Oman than in the Persian Gulf, which could be due to abiotic factors, geological events, and habitat structure

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