Paphies australis or pipi (from the Māori language) is a bivalve mollusc of the family Mesodesmatidae, endemic to New Zealand.
The pipi is a shellfish with a solid white, elongated symmetrical shell with the apex at the middle. It is covered by a thin yellow periostracum. Its closest relative, the tuatua (Paphies subtriangulata ), has an asymmetrical shell, with an off-centre hinge.
The pipi is abundant on flat sandy beaches, in sandy and silty mud in estuaries, and harbours where there is considerable water flow.
By releasing a thread of mucus, which makes them more buoyant, they are able to float in the water column and move to new locations. Where they find good living conditions, their numbers can exceed more than 1000 individuals per square metre.
