The Painted topshell (Calliostoma zizyphinum) is a beautiful mollusc that can be found on many sheltered rocky shores in the UK. This mollusc has a distinctive conical shell and a flat base which can reach sizes of up to 3cm, both in height and width! This shell is covered in roughly 10-12 whorls usually with a white base colour that is marbled with yellows, browns, pinks and purples. If you’re really lucky, you might be able to see the snail itself, which is just as colourful. You’ll notice that these shells are very clean, this is because the snail uses its extendable foot to remove any algae – around 2 times every 24 hours.
Kingdom: Animalia (Animals)
Phylum: Mollusca (Molluscs – the largest marine phylum!)
Class: Gastropoda (Gastropods – snails and slugs)
Superfamily: Trochoidea (sea snails that have gills and an operculum)
Family: Calliostomatidae (usually sea snails with tall and pointy shell)
Species: C. zizyphinum
You can find these sea snails in European waters ranging from Norway to the Azores. In the UK, you can look for the Painted topshell on rocky and sheltered lower shores that are covered in seaweed, so have a look on holdfasts for them. They can be in shallow waters or as deep as 300m!
Like most sea snails, this topshell is an important grazer, which means it glides along feeding on algae and seaweed growing on rocks. They also pick out sporelings and organic debris in the water. When cleaning their shells, they also eat anything that has been growing on there.