Comparative Osteology Study of Ariid Catfishes along the Coast of Gulf of Mannar and Wadge Bank, Tamil Nadu

Background: Taxonomic ambiguity still exists in ariid catfish species identification. Morphological similarities occur in ariid catfishes which lead to misidentification of the species. To overcome this taxonomic ambiguity osteology is one of the effective integrated taxonomic tools for species discrimination. From this study, we provide an osteotaxonomic key for the field identification of ariid catfish species. Methods: The fish samples were cleaned and washed with the freshwater put into the sample for 1% potassium hydroxide solution (KOH). Then fish samples were allowed for alkali digestion of muscle in the solution for 24-48 hours depending on the condition of the specimen. After the completion of the muscle digestion process, Alizarin S dye was used for staining the fish bones. Result: The present paper deals with a comparative study of the five Ariidae family species discussed, they are Arius arius (Hamilton,1822), Plicofollis layardi (Gunther,1866), Netuma thalassina (Ruppell, 1837), Nemapteryx caelata (Valenciennes, 1840) and Osteogeneiosus militaris (Linnaeus, 1758). The osteological portions used for this study like premaxillary, dentary, neurocranium, otolith, vertebral and caudal bone. The aforementioned osteological portions made the important primitive characters that will be used to differentiate the species.