Rare albino Powelliphanta snail
The fascinating find of a rare white-bodied giant Powelliphanta snail has been made in Kahurangi National Park.
Members of a Waimea Tramping Club party spotted the albino Powelliphanta hochstetteri hochstetteri snail in the Flora Stream area during a recent trip. The snail had its characteristic golden brown-spiralled shell but with a body that was a glowing white rather than the usual deep black colour.
Bill Brough, of Motueka, who has seen quite a number of Powelliphanta snails in his tramps, was one of three people at the rear of the party that saw the remarkable snail.
‘Our group had seen three or four snails already that morning as it had rained and they’d come out in the wet conditions. Then I saw the white snail and went wow! We were excited to see it, knowing how extraordinary it was.’
Department of Conservation Powelliphanta expert Kath Walker says in more than 30 years studying the native snails, seeing hundreds emerged from their shells, it is only the second instance of an albino Powelliphanta snail she has come across.
The first was 23 years ago in 1988, a Powelliphanta gilliesi gilliesi snail from Mt Burnett in Golden Bay which was only partially albino. It had dark internal patterning still visible on its otherwise white body and, like the recent find, still had a normally-coloured shell.
A snail of the same species with the usual black-coloured body
Bill said no patterning was apparent on the Powelliphanta hochstetteri hochstetteri he saw which he described as being off-white like Milky Bar white chocolate in colour.
Kath said albinism was known to occur in many animal species around the world. The absence in pigment, which could be partial or complete, was due to a genetically-inherited defect in the enzyme which produced melanin.
She has since searched the spot where the latest white Powelliphanta was seen but was unable to find it.
‘I was curious and interested to see the albino snail as it is exceptional to come across one. From the photos it looks to be an adult snail at least 10 years old and I am amazed it has survived this long. Its white body would make it clearly stand out to be picked off by weka or other predators.’
- Powelliphanta snails, found only in New Zealand, are the giants of the snail world with striking spiralled shells in an array of colours and patterns. They are carnivores, their favourite prey being earthworms but they also eat slugs.
- These snails live among the leaf litter on the forest floor from which they emerge in cool, wet weather. Shells are more often seen than snails out of their shells which are only spotted infrequently.
- The white snail is a brown-based Powelliphanta hochstetteri hochstetteri which grows up to 80 mm across. It is found on the Arthur and Lockett Ranges. A yellow-based form of the species lives north of Takaka Hill.
- The species is endangered due to predation by introduced pests: possums, rats, pigs and thrushes. DOC carries out possum control in the area primarily to protect the snails. The Friends of Flora community group also carries out pest control over around 5500 hectares in that part of the park to enhance the native vegetation and wildlife.