Theba macandrewiana

Theba macandrewiana is a species of land snail of the family Helicidae, endemic to the Savage Islands of Portugal. Its shell is around in length.

Distribution and habitat

It is present in the three islands where it occurs on rocky and sandy soils, beneath rocks or associated to grasses from in altitude. It is the only non-marine gastropod species known from the archipelago.

Threats

The species was threatened by previous introduction of rabbits, mice and the tobacco tree to the Selvagem Grande which were effectively eradicated in the early 2000's. Today, the species is susceptible to soil erosion and consequent landslides from rainstorms that affect the arid archipelago and also native lizards that may predate on eggs. In the longer term the species could be threatened by increased frequency of droughts and sea level changes due to climate change.
It represents about 35% of the diet of yellow-legged gulls that breed on the islands.