![]() ![]() Threatsĭespite being legally protected, New Zealand’s Powelliphanta land snails are under serious threat. The snails are most likely to be active on warm, moist nights after a long dry spell. They live buried in leaf mould or under logs. Powelliphanta are nocturnal, and come out at night to forage for food and to mate. You are unlikely to spot a live snail, except at night or occasionally on rainy days. Most of the alpine species have to contend with prolonged snowfalls and bitterly cold winters.Įmpty snail shells on the forest floor is a sign of their presences. For this reason, they are more common in moist high-altitude forest than in drier forests at lower altitudes.ĭifferent Powelliphanta species can be found from sea level, where they live in rich temperate rainforest, to above the bushline. In the North Island they are found in tiny parts of the Horowhenua plains, in some of the mountains of central North Island and on Mt Taranakiīecause Powelliphanta snails are prone to dehydration, they cannot survive in dry conditions. They are also found in the Marlborough Sounds and Richmond Ranges, and on coastal west coast mountain ranges as far south as Fiordland and Southland. The stronghold for Powelliphanta snails is in north west Nelson and north Westland, with more species here than anywhere else. Whatever the reason, it makes for a rich and interesting pattern of occupation, which is helping shed light on the past biogeography of New Zealand. It also relects past barriers to snail movement such as glaciers, rivers, lakes, mountains and volcanic ash. This is probably because of the patchiness of suitable habitat. This means each species and subspecies are confined to its own small area, with lots of country in between without any Powelliphanta at all. Powelliphanta are mostly "spot endemics". It is amazing it survived so long as its white body would make it clearly stand out to be picked off by weka or other predators. From the photos it looked to be an adult snail at least 10 years old. The absence in pigment, which could be partial or complete, was due to a genetically-inherited defect in the enzyme which produced melanin.ĭepartment of Conservation Powelliphanta expert Kath Walker said it was exceptional to come across an albino snail. The albino snail was a Powelliphanta hochstetteri hochstetteri that had its characteristic golden brown-spiralled shell but had a body that was a glowing white rather than the usual deep black colour.Īlbinism is known to occur in many animal species around the world. The fascinating find of a rare white-bodied giant Powelliphanta snail was made in the Flora Stream area of Kahurangi National Park in November 2011. In snail terms, that is an incredibly long life span! It is estimated that Powelliphanta snails can live up to 20 years.Each egg is up to 12 mm long, pearly pink and hard-shelled - just like a small bird’s egg! Powelliphanta snails lay about 5-10 large eggs a year.Powelliphanta snails are hermaphrodites, meaning they possess both male and female reproductive organs and therefore can mate with any other adult Powelliphanta.Now, Paryphanta refers only to kauri snails, which live north of Auckland. Powelliphanta snails used to be known as Paryphanta snails, until the 1970s.Powell, a former scientist at Auckland Museum who studied the snails during the 1930s and 1940s. These are the sumo wrestlers of the snail world, weighing in at 90 g, or the equivalent of a tui! The largest species is Powelliphanta superba prouseorum, found in Kahurangi National Park and measuring about 9 cm across.They particularly like earthworms, and suck them up through their mouth just like we eat spaghetti. A total of 40 species or subspecies are ranked as being of national conservation concern. Unfortunately, they are also one of the most threatened of New Zealand’s invertebrates. They are as representative of New Zealand’s unique evolutionary history as the kakapo, moa or kiwi. Their oversize shells come in an array of colours and patterns, ranging from hues of red and brown to yellow and black. Powelliphanta are giants of the snail world. Powelliphanta snails are not your common garden snail! In fact, they are totally unlike garden snails, which are a European import and an unwanted garden pest. Hidden away in New Zealand’s forests and grasslands is a bewildering array of native land snails, which range from the microscopic to the massive.Īmong these are at least 16 species and 57 sub-species of Powelliphanta – which represent some of the most distinctive invertebrates in New Zealand. ![]() Powelliphanta superba prouseorum can grow as big as a fist. ![]()
0 Comments
Leave a Reply. |