Description ⁶

 The conical shell of Patella vulgata is up to 6 cm long with radiating ridges and the apex central or slightly anterior. Individuals from the high shore generally have a taller shell and smaller shell length when compared to juveniles and low shore animals. The outer surface of the shell is greyish white or ashen, sometimes with a yellow tint, and has coarse radiating ridges and well-marked growth lines. The inner surface is smooth and greenish-grey in colour. The sole of the foot is yellowish, dull orange or brown with a grey or greenish tinge. The mantle skirt is fringed with translucent pallial tentacles arranged in three series of different lengths, internal to which lies a complete circlet of pallial gills.

Habitat ⁷

 Patella vulgata is found wherever there is substratum firm enough for its attachment on rocks, stones and in rock pools, from the high shore to the sublittoral fringe. It is abundant on all rocky shores of all degrees of wave exposure although the highest densities of Patella vulgata coincide with wave exposed conditions. The species is usually not abundant on shores with a dense growth of seaweed. Patella vulgata extends into estuaries, surviving salinities down to about 20 psu.

Biology ⁸

Although they may seem to be fixed to the rock, common limpets actually move around to graze on algae during moist conditions or when they are submerged by the tide. They return to the same spot by following the mucus trail that they deposit. This spot becomes worn by the edges of the shell, and eventually an obvious 'scar' in the rock is created. This helps the limpet to attach even more tenaciously to the rock, a strategy that protects it from desiccation (2). Common limpets begin their life as males, becoming sexually mature at around 9 months of age. Most individuals undergo a sex change, typically becoming female at 2 or 3 years of age, although some remain as males (3). Spawning takes place once a year, usually from October to December, although the timing varies around the British Isles (2). Fertilisation occurs externally; the larvae spend their first few days of life in the water column, after which time they settle on the shore (2). Life-span varies, but is between 10 and 20 years (3). In many areas, limpets have been collected as a food source for many centuries (3).

Sources and Credits

1. (c) Sandy__R, some rights reserved (CC BY), http://www.flickr.com/photos/35142635@N05/5041149585/
2. (c) Biodiversity Heritage Library, some rights reserved (CC BY), http://www.flickr.com/photos/biodivlibrary/6311725545/
3. (c) Biopix, some rights reserved (CC BY-NC), http://www.biopix.com/PhotosMedium/GDR%20Patella%20vulgata%2008268.jpg
4. (c) anonymous, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Napfschnecke3.jpg
5. (c) anonymous, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Napfschnecken_Galizien2005.jpg
6. (c)  The Marine Biological Association of the United Kingdom, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/16196852
7. (c)  The Marine Biological Association of the United Kingdom, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/10658326
8. (c) Wildscreen, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/5670892

More Info

• iNat taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
• BOLD Systems BIN search
• Global Biodiversity Information Facility (GBIF)
• NBN Atlas
• SeaLifeBase
• World Register of Marine Species

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