Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic Period.
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless.
Ovalipes ocellatus, known as the lady crab, is a species of crab from eastern North America. Other names for it include the leopard crab or Atlantic leopard crab due to the leopard-like rosette patterns on its shell, the calico crab, or ocellated crab. It has a shell 3 in (7.6 cm) long and only slightly wider, which is covered in clusters of purple spots. It occurs from Canada to Georgia, and lives mainly on molluscs, such as the Atlantic surf clam.
The Ecuadorian hermit crab also known as the Pacific hermit crab is a species of land hermit crab. It is one of the two land hermit crabs commonly sold in North America as pets, the other being the Caribbean hermit crab.
The Australian land hermit crab is a terrestrial hermit crab species, native to Australia. It is a nocturnal, omnivorous crustacean. They are gregarious and thrive in tropical areas near water.
The Coenobitidae are the family of terrestrial hermit crabs, widely known for their land-living habits as adults. They are found in coastal tropical regions around the world and require access to the ocean to breed.
The genus Coenobita contains 17 species of terrestrial hermit crabs. Several species in this genus are kept as pets.
Gecarcinus quadratus, known as the red land crab, whitespot crab, Halloween crab, moon crab, Halloween moon crab, mouthless crab, or harlequin land crab, is a colourful land crab from the family Gecarcinidae.
Soldier crab is a term used in different parts of the world for different crustaceans:
Coenobita perlatus is a species of terrestrial hermit crab. It is known as the strawberry hermit crab because of its reddish-orange colours. It is a widespread scavenger across the Indo-Pacific, and wild-caught specimens are traded to hobby aquarists.
Coenobita cavipes is a species of land hermit crab native to the eastern parts of Africa, the Indonesia, Philippines, China, Japan, Malaysia, Taiwan, Polynesia, and Micronesia. While these hermit crabs are terrestrial, they prefer to reside near the shores for access of both water and land.
Coenobita rugosus is a species of land hermit crab native to Indonesia, Australia and the east African coast to the south west Pacific.
Coenobita brevimanus is a species of terrestrial hermit crab belonging to the family Coenobitidae, which is composed of coastal living terrestrial hermit crabs. From there it belongs to the genus Coenobita, one of two genera split from the family, which contains sixteen species. The Latin origins of the species name, brevimanus, come from the adjective brevis ("small") and the noun manus ("hands"). It is known as the Indos crab or Indonesian crab because it is primarily distributed throughout the Indo-Pacific.
Thalassina is a genus of mud lobsters found in the mangrove swamps of the Indian Ocean and western Pacific Ocean. Its nocturnal burrowing is important for the recycling of nutrients in the mangrove ecosystem, although it is sometimes considered a pest of fish and prawn farms.
The coconut crab is a terrestrial species of giant hermit crab, and is also known as the robber crab or palm thief. It is the largest terrestrial arthropod known, with a weight of up to 4.1 kg (9 lb). The distance from the tip of one leg to the tip of another can be as wide as 1 m. It is found on islands across the Indian and Pacific Oceans, as far east as the Gambier Islands, Pitcairn Islands and Caroline Island and as far south as Zanzibar. While its range broadly shadows the distribution of the coconut palm, the coconut crab has been extirpated from most areas with a significant human population such as mainland Australia and Madagascar.
Gecarcinus ruricola is a species of terrestrial crab. It is the most terrestrial of the Caribbean land crabs, and is found from western Cuba across the Antilles as far east as Barbados. Common names for G. ruricola include the purple land crab, black land crab, red land crab, and zombie crab.
Johngarthia lagostoma is a species of terrestrial crab that lives on Ascension Island and three other islands in the South Atlantic. It grows to a carapace width of 110 mm (4.3 in) on Ascension Island, where it is the largest native land animal. It exists in two distinct colour morphs, one yellow and one purple, with few intermediates. The yellow morph dominates on Ascension Island, while the purple morph is more frequent on Rocas Atoll. The species differs from other Johngarthia species by the form of the third maxilliped.
Coenobita scaevola is a species of terrestrial hermit crab from the western Indian Ocean and Red Sea.
Coenobita rubescens is a species of terrestrial (land-living) hermit crab, family Coenobitidae.
Coenobita pseudorugosus is a species of terrestrial hermit crab, family Coenobitidae.
