The variability in the jaw morphology in relation to the hard prey crushing ability (durophagy) among fishes was studied by comparing the pharyngeal jaw microstructure of two durophagous teleosts and their non- durophagous relatives. The first pair comprised of members of order Anguilliformes (durophagous Gymnomuraena zebra, and piscivorous Muraenesox bagio) and the other, by the members of Order: Perciformes (durophagous Trachinotus blochii, and piscivorous Megalaspis cordyla). The Scanning electron micrographs showed long, strong , re-curved and bluntly pointed teeth in the 5th ceratobranchial (Lower pharyngeal jaw) of G. zebra as the major durophagian adaptation over the broad pharyngeal plate with numerous fine conical teeth in M. bagio. The durophagous T. blochii possessd blunt and robust molariform teeth in the broad pharyngeal plate attributed for its crushing ability in contrast with M. cordyla that showed both conical and small molariform teeth that unevenly distributed in the tooth plate. The histological sections of the pharyngeal tooth plates revealed thick dentine architecture with numerous porous spaces and very narrow pulp cavities in durophagous species as their major adaptation. The canonical discriminant function analysis for the pharyngeal jaw variables showed 99.6% and 99.2% of variability between durophagous and non-durophagous species pairs of Anguilliformes and Perciformes respectively. The maximum DFA coefficient was recorded for the lower pharyngeal jaw length between G. zebra and M. bagio (49.71)and Lower pharyngeal depth between T. blochii and M. cordyla (46.03) and hence indicating the significance of these variables in discriminating the two species based on their feeding performances. The present study gives reasonable evidences of functional diversification of the secondary feeding apparatus (pharyngeal tooth plates) even among closely related fish species for advanced prey processing capabilities.