Austrolittorina unifasciata

Austrolittorina unifasciata, common name the banded periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles. It is also known as the blue periwinkle.

Description
The shell size varies between 10 mm and 25 mm.

Distribution
This species is the only one of its genus found in Australia. It is distributed in the Coral Sea off Queensland, Australia and in the Indian Ocean off Western Australia. This common periwinkle also lives on the rocky shore of New Zealand. It is also commonly found in South Pacific Islands such as Norfolk Island.

Ecology
This species of periwinkle lives in the splash zone and high intertidal zone, where it is found in clusters of individuals. The banded periwinkle grazes on lichen and algae. This small snail is eaten by crabs and birds.