Littorina saxatilis, common name the rough periwinkle, is a species of small sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles.

Distribution

This species is native to the shores of the North Atlantic Ocean, including Hudson Bay, Baffin Island, Greenland, and the Barents Sea, south along the American East Coast to Chesapeake Bay, and along the European coast to the Straits of Gibraltar.

This species has also been introduced to San Francisco Bay, on the West Coast of the United States, where it was first observed in 1992.

Shell description

The shell in life often appears green with algae, but the shell itself can be white, red, or brown, sometimes with checkered lines. The shell has 4-5 whorls. The average size of the shell is 18 mm.

Ecology

Habitat

This species frequently lives in salt marshes. it can also be found in crevices of intertidal bedrock, in empty barnacle shells, and under rocks. Like many other periwinkles, this species can survive long exposures out of the water.

Feeding habits

This snail is a herbivore which grazes on the surface of rocks and mud flats.

See also

• Common Periwinkle

References