The seven-gilled shark (Notorynchus cepedianus), or tuatini of the Maoris, differs from all other New Zealand sharks in its having seven gill slits instead of the usual five. The dorsal fin is small and rounded and situated well back towards the tail, which has the upper fluke much the larger. In colour it is sandy-grey above and white below. The teeth are distinctive and differ in each jaw; the upper ones are more or less pointed, but the lower ones have eight or nine cusps and resemble short sections of a hacksaw blade. It grows to over 9 ft, but is rather uncommon in New Zealand. In Australia it is regarded as a dangerous species.
by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.