''Paphies subtriangulata'' is a species of edible

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

clam Clam is a common name for several kinds of bivalve mollusc. The word is often applied only to those that are deemed edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams h ...

known as tuatua in the

Māori language Māori (; endonym: 'the Māori language', commonly shortened to ) is an Eastern Polynesian languages, Eastern Polynesian language and the language of the Māori people, the indigenous population of mainland New Zealand. The southernmost membe ...

, a member of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mesodesmatidae ''Mesodesmatidae'' is a family (biology), family of saltwater clams, marine (ocean), marine bivalve mollusks in the order (biology), order Venerida.MolluscaBase eds. (2020). MolluscaBase. Mesodesmatidae Gray, 1840. Accessed through: World Registe ...

and

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to New Zealand. It is found on all three of the main New Zealand islands, buried in fine clean sand on ocean beaches. The large shell is asymmetrical, with the hinge at one side. Its closest relative, the pipi (''

Paphies australis ''Paphies australis'' or pipi (from the Māori language) is a bivalve mollusc of the family (biology), family Mesodesmatidae, endemic to New Zealand.MolluscaBase eds. (2021). MolluscaBase. Paphies australis (Gmelin, 1791). Accessed through: Wo ...

''), has a symmetrical shell. Due to their shell shape, and how they burrow underneath the sand, they can withstand the high-energy waves from the ocean. Using this knowledge, we can identify where they will adapt the most to, and this is the energetic oceanfront. Ohope Tua Tuas

The soft parts of the animal are an edible delicacy, made into

fritter A fritter is a portion of meat, seafood, fruit, vegetables, or other ingredients which have been Batter (cooking), battered or breading, breaded, or just a portion of dough without further ingredients, that is deep-frying, deep-fried. Fritters ar ...

s or boiled and served on the shell. Historically the species has been used as a food source by the Māori, and its shell is a common component of excavated Māori

midden A midden is an old dump for domestic waste. It may consist of animal bones, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and ecofacts associated with past human oc ...

s. The clam burrows beneath the sand, and does so very quickly, making it a challenge to dig for at times. It also squirts water when threatened. All tuatua are protected with legal limits on their capture. In some areas one digger may bag no more than 50 to 150 tuatuas per day, depending on location.

Subspecies

Three subspecies have been recognised: *''Paphies subtriangulata subtriangulata'' (Wood, 1828)
Distribution: throughout North and South Islands
Maximum length is , height , and thickness . *''Paphies subtriangulata porrecta'' ( Marwick, 1928)
Distribution:

Chatham Islands The Chatham Islands ( ; Moriori language, Moriori: , 'Misty Sun'; ) are an archipelago in the Pacific Ocean about east of New Zealand's South Island, administered as part of New Zealand, and consisting of about 10 islands within an approxima ...

Maximum length: , maximum height: . *''Paphies subtriangulata quoyii'' ( Deshayes, 1832)
Distribution: throughout North and South Islands
Size: Thicker relative to length - Maximum length is , height , and thickness .

References

* Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 *B. Foss Leach, Janet M. Davidson, Meredith Roberthawe, Penelope C. Leach., (2001). ''
Identification, Nutritional Yield, and Economic Role of Tuatua Shellfish, Paphies spp., in New Zealand Archaeological Sites
'', The Japanese Society for Oceanic Studies. Retrieved 19 March 2025. {{Taxonbar, from=Q3017042 Commercial molluscs Bivalves of New Zealand Endemic fauna of New Zealand Mesodesmatidae Bivalves described in 1828 Taxa named by William Wood (zoologist) New Zealand seafood Endemic molluscs of New Zealand