Littorina littorea

Common periwinkle
Periwinkle emerging from its shell, Sweden
L. littorea on the edge of a small sandy beach in Woods Hole, Massachusetts
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha
Superfamily:	Littorinoidea
Family:	Littorinidae
Genus:	Littorina
Species:	Littorina littorea
Binomial name
Littorina littorea (Linnaeus, 1758)
Synonyms
Littorina armoricana Locard, 1886 Littorina bartonensis Brown, 1843 Littorina communis Brown, 1843 Littorina litorea (Turton, 1819) Littorina litorea var. brevicula Jeffreys, 1865 Littorina litorea var. paupercula Jeffreys, 1865 Littorina litorea var. sinistrorsa Jeffreys, 1865 Littorina litorea var. turrita Jeffreys, 1865 Littorina littorea f. intermedia Brøgger, 1901 Littorina littorea var. angulata Harmer, 1920 Littorina littorea var. antiqua Wood, 1848 Littorina littorea var. balteata Dautzenberg & Durouchoux, 1912 Littorina littorea var. complanata Harmer, 1920 Littorina littorea var. conica Harmer, 1920 Littorina littorea var. deformis Wood, 1848 Littorina littorea var. delphinula Wood, 1848 Littorina littorea var. distorta Harmer, 1920 Littorina littorea var. elegans Wood, 1848 Littorina littorea var. fuscofasciatus Middendorff, 1849 Littorina littorea var. major Dautzenberg & Durouchoux, 1913 Littorina littorea var. miniata Dautzenberg & Durouchoux, 1900 Littorina littorea var. pallida Dautzenberg & Durouchoux, 1900 Littorina littorea var. pallidefasciatus Middendorff, 1849 Littorina littorea var. parva Harmer, 1920 Littorina littorea var. picta Wood, 1848 Littorina littorea var. pyramidata Wood, 1848 Littorina littorea var. sanguinea Dautzenberg & Durouchoux, 1906 Littorina littorea var. truncata Harmer, 1920 Littorina littorea var. unicarinata Raeymaekers, 1889 Littorina parva Teilman-Friis, 1898 Littorina rudis var. aurantia Dautzenberg & P. Fischer, 1925 Littorina rudis var. reevei Harmer, 1921 Littorina sphaeroidalis Locard, 1886 Littorina vulgaris J. Sowerby, 1832 Turbo bicarinatus Woodward, 1833 Turbo carinatus Woodward, 1833 Turbo elongatus Woodward, 1833 Turbo litoreus Turton, 1819 Turbo littoreus Linnaeus, 1758 (basionym) Turbo sulcatus Woodward, 1833 Turbo ustulatus Lamarck, 1822 Turbo ventricosus Woodward, 1833

External video

Dredging for periwinkles, YouTube video

Snorkeling for periwinkles, YouTube video

The common periwinkle or winkle (Littorina littorea) is a species of small edible sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles.

This is a robust intertidal species with a dark and sometimes banded shell. It is native to the rocky shores of the northeastern, and introduced to the northwestern, Atlantic Ocean.

There is another snail known as small periwinkle or Melarhaphe neritoides that looks similar, but is smaller in size.

The shell is broadly ovate, thick, and sharply pointed except when eroded. The shell contains six to seven whorls with some fine threads and wrinkles. The color is variable from grayish to gray-brown, often with dark spiral bands. The base of the columella is white. The shell lacks an umbilicus. The white outer lip is sometimes checkered with brown patches. The inside of the shell has a chocolate-brown color.

The width of the shell ranges from 10 to 12 mm at maturity, with an average length of 16–38 mm.

Shell height can reach up to 30 mm, 43 mm or 52 mm.

As a result of its robust nature, Littorina littorea can be highly variable in phenotype with several different morphs present. Its phenotypic variations may be indicative of a speciation event, as opposed to phenotypic plasticity. This is of particular importance to evolutionary biology, as it presents the possible opportunity to view a transitional phase in the evolutionary life of an organism.

Measuring the shell from the end of the aperture to the apex reveals the length of the snail. Turning the shell over with the aperture flat on a surface and measuring vertically reveals the height of the snail. These measurements can be done using a caliper.

Common periwinkles are native to the northeastern coasts of the Atlantic Ocean, including northern Spain, France, England, Wales, Scotland, Ireland, Scandinavia, and Russia.

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Wikipedia