A new species of electric ray of the genus Narcine Henle, 1834 from the south-western Indian Ocean (Chondrichthyes: Torpediniformes: Narcinidae)

A new species of electric ray of the genus Narcine Henle, 1834 is described from seven specimens collected from two localities off the western coast of Madagascar, in the Mocambique Channel. Narcine insolita, sp. nov. is distinguished from all other species of the genus by the unique presence of a very prominent first dorsal fin that is much greater than the second dorsal fin in both height and length of base. A unique combination of characters further distinguishes N. insolita, including large and bulging eyes, large circular spiracles with elevated rims, interorbital distance much greater than interspiracular distance, rounded cusplets lateral to principal cusp on teeth of inner tooth rows, broadly rounded tooth bands, dorsal colouration composed of a yellowish brown background with large dark brown to reddish brown blotches at disc margins and over dorsal and caudal fins, and numbers of precaudal and total vertebral centra. N. insolita is similar but distinct from the recently described Narcine oculifera from the Gulfs of Oman and Aden, with which it is compared. An additional specimen of Narcine from the coast of Mocambique also presents features in common with our new species. However, it is not currently included in N. insolita, because it lacks its autapomorphic dorsal fin proportions. This specimen probably, represents a further undescribed species of Narcine from the south-western Indian Ocean, but more specimens from Mocambique are required for further evaluation. The new species represents only the third described species of Narcine from the western Indian Ocean.