Portunidae is a family of crabs which contains the swimming crabs. Its members include many well-known shoreline crabs, such as the blue crab and velvet crab. Two genera in the family are contrastingly named Scylla and Charybdis; the former contains the economically important species black crab and Scylla paramamosain.
The Ocypodidae are a family of semiterrestrial crabs that includes the ghost crabs and fiddler crabs. They are found on tropical and temperate shorelines around the world.
Majidae is a family of crabs, comprising around 200 marine species inside 52 genera, with a carapace that is longer than it is broad, and which forms a point at the front. The legs can be very long in some species, leading to the name "spider crab". The exoskeleton is covered with bristles to which the crab attaches algae and other items to act as camouflage.
Liocarcinus vernalis, the grey swimming crab, is a small, shallow-water crab in the family Portunidae. L. vernalis was thought for a long time to be a predominantly Mediterranean species, but its known range was extended by a series of observations in the 1980s and 1990s. It ranges from West Africa to the southern North Sea.
Liocarcinus marmoreus, sometimes known as the marbled swimming crab, is a species of crab found in the northern Atlantic Ocean and North Sea. It may be found on sand and gravel in the sublittoral and lower littoral zones, down to a depth of 84 metres (276 ft), from the Azores and the Alboran Sea as far north as the Shetland Islands. It reaches a carapace length of 35 millimetres (1.4 in), and is distinguished from other similar species by the presence of three similarly sized teeth on the edge of the carapace, between the eyes, and by the marbled colouration on the carapace. L. marmoreus is sometimes parasitised by the barnacle Sacculina.
Liocarcinus depurator, sometimes called the harbour crab or sandy swimming crab, is a species of crab found in the North Sea, Atlantic Ocean, Mediterranean Sea, and Black Sea. It grows up to 50 millimetres (2.0 in) in width and 40 mm (1.6 in) long, and can be distinguished from other crabs, such as the shore crab Carcinus maenas, by the curved rows of white spots on its carapace.
Liocarcinus holsatus, sometimes known by the common name flying crab, is a species of swimming crab found chiefly in the North Sea, Irish Sea and English Channel. It has a carapace up to 4 centimetres (1.6 in) wide, which is brownish-grey with a green tinge. It is very similar in appearance to the harbour crab Liocarcinus depurator.
Corystidae is a family of crabs, in its own superfamily, Corystoidea. It includes what was once thought to be the oldest Eubrachyuran fossil, Hebertides jurassica, thought to be dating from the Bathonian ; the species was subsequently reinterpreted as being Cenozoic in age. Corystidae contains ten extant and five extinct species in eight genera:
Liocarcinus navigator is a species of crab in the family Portunidae.
Liocarcinus pusillus, common name dwarf swimming crab, is a species of crab in the Portunidae family.
Ciliopagurus substriatiformis was a species of hermit crab that existed during the Badenian stage.
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.
Leucosiidae is a family of crabs containing three subfamilies and a number of genera incertae sedis:
Mesoparapylocheles is an extinct hermit crab genus which existed during the Mesozoic in what is now Europe. It was described by René H.B. Fraaije, Adiël A. Klompmaker and Pedro Artal in 2012. The type species is Mesoparapylocheles michaeljacksoni from the Albian or Cenomanian of Spain; which was named after the singer Michael Jackson. Genus also includes other species from the Late Jurassic (Kimmeridgian) of Germany and from the Late Jurassic (Tithonian) of Austria.
Around 65 species of crab occur in the waters of the British Isles. All are marine, with the exception of the introduced Chinese mitten crab, Eriocheir sinensis, which occurs in fresh and brackish water. They range in size from the deep-water species Paromola cuvieri, which can reach a claw span of 1.2 metres, to the pea crab, which is only 4 mm (0.16 in) wide and lives inside mussel shells.
Goniodromites is an extinct genus of crabs. A new species, G. kubai, which existed during the Oxfordian stage of what is now Poland, was described by Natalia Starzyk, Ewa Krzemiska and Wiesław Krzemiski in 2012.
Liocarcinus zariquieyi is a species of crab found in the Mediterranean Sea. It closely resembles Liocarcinus pusillus and was for a long time confused with that species.
Calappilia is an extinct genus of box crabs belonging to the family Calappidae. The type species of the genus is Calappilia verrucosa.
Randallia is a genus of true crabs in the family Leucosiidae. There are about 17 described species in Randallia.
