NARCINE LASTI, A NEW SPECIES OF NUMBFISH FROM WESTERN AUSTRALIA AND INDONESIA (CHONDRICHTHYES TORPEDINIFORMES NARCINIDAE)

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Narcine lasti, n. sp., is described from abundant material mostly collected from the Western Australian coast. The new species is distributed from Green Head and the Houtman Abrolhos in the eastern Indian Ocean to southeastern Indonesia in the Arafura Sea, along the upper continental slope. Narcine lasti is distinguished by a unique combination of characters including a tail length much longer than disc width or length, uniform yellowish-brown to yellowish-pink dorsal colouration that also extends anteriorly over preorbital snout region, lateral tail folds low and ridge-like, disc width and length with means of 40.3 and 42.1 % of total length (TL) respectively, nasal curtain much wider than long, and preorbital snout length over 10 % of TL. Narcine lasti is most similar to N. tasmaniensis and another undescribed species
of Narcine from off the Queensland coast of Australia. All three species have relatively similar proportions and dorsal colouration, but can be distinguished on the basis of preorbital snout length, disc width and length, lateral tail fold morphology and usually also in dorsal colouration. Narcine lasti is easily distinguished from Narcine westraliensis McKay, 1966, the only other species of the genus in Western Australia, by many features including disc shape, relative proportions of the tooth bands, and in dorsal colouration. Both species do not co-occur, as N. westraliensis is distributed on the continental shelf in relatively shallow waters, while N. lasti is confined to deeper waters of the continental slope.