Common Periwinkle (Littorina littorea)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Littorinidae, Genus: Littorina, Species: Littorina littorea · Littorinidae (Periwinkle family) · Gastropod (snail/univalve), whole shell, spiral shape
Species
Littorina littorea
Shell Type
Gastropod (snail/univalve), whole shell, spiral shape
Family
Littorinidae (Periwinkle family)
Size
Approximately 0.75 inches (20 mm) in length and width, which is average for this species. Adults typically range from 0.5 to 1.25 inches.
Color & Pattern
Dull brownish-grey base color with subtle darker spiral banding and fine growth lines. The apical whorls show some dark purplish-grey tones. Colors appear slightly weathered and natural.
Rarity
Very Common
Habitat
Intertidal zone, typically found on rocky shores, attaching to rocks, pilings, and seaweeds in areas exposed to wave action. Marine to brackish environment.
Geographic Range
Native to the rocky shores of northeastern Atlantic (Europe), introduced and widespread along the northeastern coast of North America from Labrador to New Jersey.
Description
A compact, robust, conical snail shell with a short spire and rounded body whorl. The surface features fine spiral striae and growth lines, giving it a slightly textured feel. The aperture is oval and simple without a prominent siphonal canal.
Key Features
Rounded conical shape, relatively thick and solid walls, dark greyish-brown exterior with faint spiral bands, and lack of a distinct columellar fold.
Collector Value
Low collector value due to extreme commonness, but frequently collected by casual beachcombers and children. Valued mostly as educational specimens or for crafts.
Condition Notes
Good condition. Intact overall structure with some minor natural wear and bleaching on the spire. Collectibility grade is Good.
Interesting Facts
The common periwinkle is an edible marine snail that was introduced to North America from Europe in the 19th century. They are efficient grazers of microalgae and can tolerate long periods out of water during low tide by sealing their aperture.
Ecological Role
Acts as an important herbivore controlling algae populations on rocky intertidal shores. Serves as prey for various crabs, seabirds, and fish.
Similar Species
Rough Periwinkle (Littorina saxatilis) and Smooth Periwinkle (Littorina obtusata). Distinguished by size, texture of spiral ridges, and preferred intertidal microhabitat.
Beach Finding Tips
Look along rocky shores, tide pools, and jetties during low tide. They are often clustered near or under seaweeds and rocks in the mid-to-high intertidal zone.