Bristly Crab (Pilumnus hirtellus)
Also known as the hairy crab, this species of crab is very small, being just 2 to 3cm across when fully grown. The bristly crab is mostly found around the south and west of the British Isles, and generally stays within the intertidal zone. Its body and legs are reddish-brown in colour and are covered in hair-like structures which give this crab its name. Like all crabs it has eight legs and two claws, with one claw (usually the right) being larger than the other. Its diet is primarily made up of dead and rotting marine matter.
Masked Crab (Corystes cassivelaunus)
The masked crab is a species of crab which is present mostly around the south and west of the British Isles, although smaller isolated populations are present elsewhere across the country and is also found throughout European waters. It is a small species of crab with a carapace measuring just a few centimetres across. It lives on sandy and muddy seabeds and buries itself into the sediment with its long antenna poking out. They generally live just outside the intertidal zone and down to depths of around one hundred metres. It feeds on marine worms and any other small creatures which are found in the sand and sediment where this crab is present.
Broad Clawed Porcelain Crab (Porcellana platycheles)
This species of crab is often found under rocks and boulders in heavy rocky coastlines. It has a widespread but sporadic distribution around most of the British Isles. It is a small crab species, rarely exceeding 15 to 18mm across the carapace, and is usually a green to grey colour and can be easily distinguished by its very broad claws and very long antenna. There is a second species of porcelain crab in British waters – the long clawed porcelain crab (Pisidia longicornis). This species is smaller in size, rarely reaching 10mm across the carapace and (unsurprisingly) has longer claws. It also has a less hairy appearance and is often a more reddish colour.
Spiny Squat Lobster (Galathea strigosa)
The spiny squat lobster is the largest of the squat lobster species in UK waters and is also found throughout Europe. It has small spines which cover the claws and legs. Sometimes there can be additional growth on the claws which can look like thick hairs. There are also blue streaks going along the carapace of the spiny squat lobster which make this species easily identifiable.
Other Crab and Lobster Species Found in UK Waters
There are several other crab species which are found around the UK. These include the circular crab (Atelecyclus rotundatus) which is found around most of the UK coastline and also in offshore waters several hundred metres deep. It grows to a size of around 5cm across the carapace. There is also the furrowed crab (Xantho incisus), which is also known as the grooved crab and Montagu’s crab. This species is usually a chocolate brown in colour and also grows to 5cm across the carapace. Another species which is widely consumed but little known is Nephrops norvegicus. This is also called the Norway Lobster, Dublin Bay Prawn, and langoustine, but is without doubt best known as scampi where it is immensely popular in restaurants and in frozen form in supermarkets. It is nocturnal and feeds mostly on plant matter. Finally, there is also the pea crab (Pinnotheres Pisum). This species is tiny – literally the size of a pea – and lives as a parasite on shellfish.