The Powelliphanta is the largest land snail species on earth. It is air breathing and carnivorous feeding on earthworms and slugs like spaghetti. These snails are endemic to New Zealand and prefer moist environments from sea level to above the tree line.
Over 20 species have been recorded including another 51 subspecies that have evolved from different habitats, altitudes and moisture levels. The largest kind is the Powelliphanta superba prouseorum. It's shell may grow up to 9 cm in diameter and weigh up to 90 g. Since 1982, collecting the shells is illegal.
The Powelliphanta is a hermaphrodite that can only survive in moist surroundings. Powelliphanta traverse prefer to live in wet tussock lands above the treeline. Kahurangi National Park counts the greatest number of Powelliphanta in New Zealand. However, several species are threatened through introduced predators such as pigs, possums, hedgehogs and rats.
The subspecies Powelliphanta gilliesi is only to be found in an area of one hectare in the west of Nelson Lakes National Park.