Scientific name: Paphies subtriangulata

The Tuatua lives in crowded beds on open beaches exposed to surf. It is smooth, and wedge shaped, with a thick shell. It lives at or below the low tide level and uses its strong foot to dig in quickly if a wave washes it out of the sand - something that happens often as they live just below the surface of the sand. On west coast beaches they form dense, but localised beds which migrate as a group up and down the shore. This makes them difficult to measure as the beds don't remain in one place from one survey to the next and even finding them can be a problem.

Tuatua are found around most of the New Zealand coast, and the east coast specimens are generally smaller than those of the west coast.

Tuatua grow to about 60-mm in shell length and, like other bivalves, filter the sea water for planktonic organisms through two very short siphons.

Tuatua are greatly prized, and have a sweeter flesh than the larger Toheroa. Many of the Maori shell middens are testimony to the long standing enjoyment of these shellfish by New Zealanders.