Flat Periwinkle

Littorina obtusata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.

Distribution

This marine species occurs wherever brown seaweeds grow. It is widely distributed : the Baltic Sea, in European waters from Norway down to Southern Spain, in the Mediterranean Sea, in the Northwest Atlantic Ocean along the Gulf of Maine.

Description

The maximum recorded shell length is 13.5 mm.

Habitat

This species can be found in the littoral and sublittoral zone on rocky shores and piers, usually on brown algae of the genus Fucus. Minimum recorded depth is 0 m. Maximum recorded depth is 110 m. The habitat defines its color. On sheltered shores it has a lighter and uniform color (yellow, brown, orange or olive green). On exposed shores its color is darker and chequered.