Biodiversity & Conservation

Rough periwinkle - Littorina saxatilis

Littorina saxatilis

Image Sue Scott - Littorina saxatilis, rough periwinkles amongst barnacles, Semibalanus balanoides. Image width ca 12 cm.
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Distribution map

Littorina saxatilis recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Littorina saxatilis is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Gastropoda Snails, slugs & sea butterflies
Authority (Olivi, 1792)
Recent synonyms See Additional information
Map icon Recorded Distribution in Britain and Ireland Common around the coasts of Britain and Ireland.
Habitat information icon Habitat information Littorina saxatilis occurs from the upper eulittoral zone down to the littoral fringe of the intertidal and is typically found in crevices of bedrock, empty barnacle shells and under stones. Littorina saxatilis occurs on salt marshes on the base of Spartina species and on firm mud banks. It also occurs submerged in sheltered, brackish lagoons generally attached to Zostera, Fucus, Ruppia and Potamogeton species.
Text page icon Description Littorina saxatilis has a plump shell, up to 18 mm in height and 14mm wide with a low spire of 4-5 whorls. The sculpture of the whorls are often V-shaped in section, with deep sutures. The aperture is large and rounded, with the outer lip everted slightly where it meets the columella. The colour of the shell is variable - yellowish white, greenish, reddish, brown - but usually has some pattern and a dark throat.
Identifying features
  • A plump shell with 4-5 whorls and deep sutures.
  • The shell is 18 mm high and 14 mm wide.
  • The aperture of the shell is large, rounded and has a slightly everted lip.
  • The throat of the shell is darker than the outer shell surface.
Additional information icon Additional information Littorina saxatilis is a highly polymorphic species and there is disagreement about whether morphologically and genetically varied populations should be considered as sub-species or ecotypes. For a full review of littorinids in general, and a comprehensive discussion of past and current views on separating Littorina saxatilis into sub-species see Reid (1996). Reid (1996) also lists all previous synonyms for Littorina saxatilis. Littorina compressa and Littorina arcana are very similar in appearance to Littorina saxatilis. All three species occur together on rocky shores between the Barents Sea and southern Brittany, including the British Isles. See Reid (1996) for distinguishing features.

This review can be cited as follows:

Susie Ballerstedt 2007. Littorina saxatilis. Rough periwinkle. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 22/05/2012]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3715>