Powelliphanta is a genus of large, air-breathing land snails, pulmonate gastropods in the family Rhytididae, found only in New Zealand. They are carnivorous, eating invertebrates, mostly native earthworms. Often restricted to very small areas of moist forest, they are prey to introduced mammalian predators, and many species are threatened or endangered.
Powelliphanta was originally described by A. C. O'Connor in 1945 as a subgenus of the kauri snails, Paryphanta. They were named "in recognition of the great service rendered to the study of the family by Mr A. W. B. Powell", and from their similarity to Paryphanta.[1]
Shell generally, similar to Paryphanta Albers, but with the last whorl pulled in closer to the preceding whorl, and with a colour pattern of concentric or radially arranged bands, usually of alternating and contrasting colours. More important is the paucity of lime compared with conchin in the shell.
Distribution: North Island of New Zealand, in and south of the Ruahine Range (possibly once as far north as East Cape) and South Island.
Powelliphanta will include all New Zealand species previously included in Paryphanta except the type of that genus, P. busbyi (Gray, 1840) which is confined to the North Auckland Peninsula.
In 1977 Climo raised Powelliphanta to genus rank, retaining just two species in Paryphanta.[2] There are at least 21 species and 51 subspecies within the genus.[3] The relationship between the species is complex, and it has been suggested that the group Powelliphanta gilliesi-traversi-hochstetteri-rossiana-lignaria-superba forms a ring species.[4]