HISTOLOGICAL STUDY OF ODONTOGENESIS IN THE PHARYNGEAL JAWS OF TRACHINOTUS-TERAIA (CUVIER ET VALENCIENNES, 1832) (OSTEICHTHYES, TELEOSTEI, CARANGIDAE)

A histomorphological study of the development of the pharyngeal jaws in the Carangid fish Trachinotus teraia shows that they transform progressively from tiny organs with sharp superficial teeth, to thick ones with rounded teeth embedded in bony tissue. The morphological transformations take place simultaneously with a shift to a diet based on molluscs. Though odontogenesis takes place deep in the pharyngeal jaws, at all developmental stages, pharyngeal epithelium participates to the formation of teeth. Long epithelial strands penetrate in the depth of the bony jaw and here induce differentiation of ''bell organs.'' As the young teeth migrate passively toward the occlusal surface, while the jaw grows, the pharyngeal jaws of Trachinotus teraia almost behave like the ''coalesced'' teeth of the Tetraodontidae with respect to the morphogenetic processes of their growth. The developmental phenotypic plasticity of the pharyngeal jaws of Trachinotus teraia then may be compared to that of various molluscivore cichlids. (C) 1994 Wiley-Liss, Inc.