Notodiscus hookeri

Notodiscus hookeri has a wide distribution in the sub-Antarctic region. It is the only native terrestrial gastropod species found in the South Indian Ocean islands and archipelagos, and also in the South Atlantic Province: South Indian Province:

Crozet Islands. For example, Notodiscus hookeri is the only terrestrial snail among about 50 species of native invertebrates in the Crozet Islands. Kerguelen Islands Heard Island Prince Edward Islands South Atlantic Province:

Notodiscus hookeri is limited to South Georgia in the South Atlantic Province. The type locality is the Kerguelen Islands. The land snail Notodiscus hookeri is not an endangered or a protected species.

This land snail is a gregarious species that lives under moist stones, moss and wet vegetation; however, it is also widespread in fell-field areas, which are characterised by very low vegetation cover. This snail live in relatively simple ecosystems, that is caused by harsh environmental conditions on subantarctic islands. It is a litter-dwelling species. The soil is known to be a nutrient resource for Notodiscus hookeri, since this species has been found to significantly increase calcium release in solutions derived from plant litter.

Notodiscus hookeri exclusively feeds on lichens such as Orceolina kerguelensis, Usnea taylorii and Pseudocyphellaria crocata. Notodiscus hookeri appears as a generalist lichen feeder able to consume toxic metabolite-containing lichens. Hatchlings have a shell width of < 2.0 mm. Juveniles have a shell width of about 2.0-4.0 mm. Adults have a shell width larger than 4.0 mm. The biology of this species is poorly known.