Cook's Turban Shell

Cookia sulcata

Cook's turban shell (Cookia sulcata) is a large marine gastropod in the family Turbinidae, endemic to New Zealand. The shell reaches 50-90 mm in diameter with a thick, heavy, conical-turbinate shape displaying prominent spiral ridges and a pearly iridescent interior visible around the aperture. The exterior is typically brownish to greenish with encrusting organisms. The animal itself has a large, muscular foot with a thick, calcareous operculum for sealing the shell opening. This species inhabits rocky shore intertidal and subtidal zones at depths of 0-15 meters around New Zealand's coastline. Cook's turban shells are herbivorous, grazing on turfing and other small algae growing on rocky surfaces. They are an ecologically important species in New Zealand's temperate reef ecosystems and are culturally significant to Maori as a traditional food source. Their large, attractive shells make them easy to spot on reef walks and dives.