The morphological analysis of the bones is a valuable tool for taxonomy, which has allowed the definition of the higher groups of vertebrates and descriptions and identifications of fish species. Therefore, the compared osteology provides valuable diagnostic elements in biodiversity studies, ecology and dynamics of trophic habits of piscivore fish. The goal of the present study is to make a descriptive and comparative osteological analysis that allow the identification of the main fish species occurring in Mar Chiquita coastal lagoon: the brazilian menhaden (Brevoortia aurea), the mullet (Mugil platanus), the silver side (Odontesthes argentinensis), the white croaker (Micropogonias furnieri), the black drum (Pogonias cromis), the flounder (Paralichthys orbignyanus), the blue fish (Pomatomus saltatrix), the stripped weakfish (Cynoscion guatucupa) and the southern kingfish (Menticirrhus americanus). Six specimens of each species were analyzed and methods to disarticulate skeletons in fresh and frozen specimens were used. On the basis of the diagnostic characteristics of the bones and their degree of digestibility resistance, eleven bones were selected: parasphenoid, lachrymal, premaxilla, dentary, anguloarticular, palatine, hyomandibular, ceratohyal, urohyal, preopercle and posttemporal. Each bone has been described, and according to the most important differences found among fish species, identification keys were elaborated. We conclude that bone morphology constitutes a valuable diagnostic tool for the identification of fish species occurring in Mar Chiquita coastal lagoon and coastal adjacent areas.