A really hardy snail

During the first two centuries, a new species of invertebrate has been described in a restricted area of the Antarctic Peninsula: the first "polar" snail, Notodiscus antarcticus, also called King George snail. Even if it's technically out from the Antarctic circle, it lives in the most inhospitable place for a snail, eating mosses and lichens in the few warm months of the year, between December and February. Its origin and evolutionary history are still unknown at the moment.

Like other species of the genus Notodiscus, it possesses an excellent cold tolerance and can fall in lethargy for even 9 months, hidden under the frozen ground. This new species was once endemic to the South Shetland Islands, but it was recently observed in many southern islands and even in three locations of the Antarctic Peninsula. This sudden range expansion of this snail was probably caused by humans' accidental (or even voluntary) introductions. Some eradications were tried between 2050 and 2200, with poor success, due to the elusiveness of this species (microscopic size and mimetic coloration). Scientists have finally decided to give up since eradication methods were more deleterious to the habitat than the snail itself. Instead, the occurrence of the King George snail was beneficial in some way to flora diversity, since its grazing action disturbs dominant mosses, favoring the presence of less competitive species.

A sketch of Notodiscus antarcticus. Its shells do not exceed 5 mm in diameter (0,2 inches).