Biodiversity & Conservation

Dog whelk - Nucella lapillus - General information

Nucella lapillus

Image Judith Oakley - Group of Nucella lapillus and eggs on an overhang (the photograph is upside-down to aid identification). Image width ca XX cm.
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Distribution map

Nucella lapillus 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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General information

Key Icon Researched by: Dr Harvey Tyler-Walters Text page icon Refereed by: Dr John Crothers

Taxonomy icon Taxonomy

Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Gastropoda Snails, slugs & sea butterflies
Map icon Recorded distribution in Britain and Ireland Common on all rocky coasts of Britain and Ireland.
Habitat information icon Habitat information Found on wave exposed to sheltered rocky shores from the mid shore downwards. Rarely present in the sublittoral but may be abundant in areas exposed to extremely strong tidal stress. They are gregarious and common amongst barnacles and mussels on which they feed.
Text page icon Description The shell is broadly conical, bearing spiral ridges and consisting of a short pointed spire, dominated by the last whorl. The shell is usually up to 3 cm in height by 2 cm broad but may reach up to 6 cm in height (Crothers, 1985). The shell colour is variable, usually white, but may be grey, brown, or yellow, occasionally with contrasting (usually brown) spiral banding. A short, open siphonal canal leads from base of the aperture. The outer lip of the aperture is thin in young specimens, becoming thickened and toothed internally with age. The shell shape, shell thickness and relative size of the aperture vary with wave exposure. In some populations, mainly sublittoral or from the intertidal in North Kent, the growth lines extend outwards to form flounces or ruffles, and this variety of dog whelk is called Nucella lapillus var. imbricata. The animal itself is white or cream coloured with white speckles, and a flattened head. The head bears two tentacles, each bearing a eye about one third of the length of the tentacle from its base. The egg capsules of Nucella lapillus are vase shaped, about 8mm high, usually yellow, and found attached to hard substrata in crevices and under overhangs.

This review can be cited as follows:

Dr Harvey Tyler-Walters 2007. Nucella lapillus. Dog whelk. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesfullreview.php?speciesID=3913>