Magnificent helicarionid land snail

By Rebecca Nadge 8 February 2014
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The extremely limited distribution of the magnificent helicarionid land snail has made it vulnerable to extinction

IUCN status
Not assessed

Critically Endangered

The snail is limited to the peaks of Mount Gower and Mount Lidgbird on Lord Howe Island. The total area occupied by the snail is thought to be less than 28 hectares.

Magnificent helicarionid land snail

Very little information has been published on the habitat of the snail.

Phylum Mollusca
Class Gastropoda
Order Pulmonata
Family Helicarionidae
Genus Gudeoconcha
Species sophiae magnifica

The magnificent helicarionid land snail has a bronze coloured shell covered in minute ripples, and grows up to 35mm in diameter and 20mm high.

Little is known about the lifecycle of the subspecies, and limited records make it difficult to determine the extent of the snails’ decline. Although 45 specimens were collected between 1907 and 1915, a more recent survey from 1998 to 2002 yielded only 29, and the last three years saw no specimens recorded on Mount Lidgbird.

Threats to the magnificent helicarionid land snail

Predation by introduced species has been detrimental to numbers of the magnificent helicarionid land snail. The ship rat, which arrived on Lord Howe Island in 1918, has been declared a major threat by the NSW Scientific Committee and is thought to be responsible for the extinction of two other snail species from the same area. In addition, feral bird species such as the song thrush and the common blackbird may prey on the snail, and invasive ant species are also listed as a potential threat.

Habitat damage has also played a part in the subspecies’ decline. Before their eradication, feral pigs and goats disrupted the snails’ fragile habitat; now the snail is susceptible to disturbance by humans, weeds and bushfires. Despite Lord Howe Island’s World Heritage Listing, the snails’ low population numbers and confinement has left it vulnerable to interference and natural events.

Recovery plans for the magnificent helicarionid land snail

There is no recovery plan in place for the snail, as the Lord Howe Island Biodiversity Management Plan is deemed sufficient. Conservation advice for the snail includes further research into the biodiversity and ecology of the subspecies, managing existing populations, and monitoring the effect of rodent eradication projects.

More Information

Australian Conservation Status
Australian endangered species list