The Olfactory Mucosa of Butter Catfish Clupisoma garua (Siluriformes, Ailiidae): An Ultrastructural Study

OBJECTIVE: The olfactory system is one of the most important chemosensory systems for teleosts. The olfactory epithelium of freshwater catfish Clupisoma garua (Siluriformes, Ailiidae) was studied by the aid of light microscopy and transmission electron microscopy. MATERIALS AND METHODS: Mature sex-independent fish species were collected from Hooghly River, a distributary channel of river Ganga. Following routine procedure of ultrastructural techniques, different sensory and nonsensory cells lining the olfactory epithelium were described. RESULTS: The lamella contained two epithelia, with a central core sandwiched in between. Based on distribution pattern and structural characteristics of cell, each olfactory lamella was differentiated into sensory and nonsensory epithelium. The smaller sensory epithelium contained morphologically distinct ciliated, microvillous, and rod receptor cells, distinguished based on staining patterns, characteristic length, and architecture of their dendritic terminals. The nonsensory epithelium comprising the greater surface area was made up of labyrinth cells, mast cells, supporting cells, ciliated nonsensory cells, and basal cells. The cilia furnished a characteristic 9 + 2 microtubule arrangement. CONCLUSION: The functional significance of various cells on the olfactory epithelium was correlated with behavior of the fish concerned.