Terrestrial crab Temporal range: | |
---|---|
Purple land crab ( Gecarcinus ruricola ) | |
Purple marsh crab ( Sesarma reticulatum ) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Section: | Eubrachyura |
Groups included | |
A number of lineages of crabs have evolved to live predominantly on land. Examples of terrestrial crabs are found in the families Gecarcinidae and Gecarcinucidae, as well as in selected genera from other families, such as Sesarma , [1] although the term "land crab" is often used to mean solely the family Gecarcinidae. [2]
No clear distinction is made between "terrestrial", "semiterrestrial", and "aquatic" crabs. [2] Rather, a continuum of terrestriality is displayed among the true crabs, although most land-adapted crabs must still return to water to release their eggs. [3] Some species of terrestrial crabs can be found many kilometres from the sea, but have to complete annual migrations to the sea. [3] For example, following the Indian Ocean monsoon, the Christmas Island red crab (Gecarcoidea natalis) migrates en masse, forming a "living carpet" of crabs. The crabs can travel up to 1.46 km (0.91 mi) in a day, and up to 4 km (2.5 mi) in total. [4] Only a few land crabs, including certain Geosesarma species, have direct development (the mother carries the eggs until they have become tiny, fully developed crabs), and these do not need access to water to breed. [5] [6] Many crabs belonging to the family Potamidae, which contains mostly freshwater crabs, have developed a semiterrestrial (for instance the genus Nanhaipotamon [7] ) to terrestrial life history, and are sometimes independent of fresh water for reproduction (for instance the genus Tiwaripotamon [8] ).
Terrestrial crabs are often similar to freshwater crabs, since the physiological changes needed for living in fresh water are preadaptations for terrestrial living. [9] On some oceanic islands, terrestrial crabs occupy the top of the energy pyramid. [2]
Ghost crabs are semiterrestrial crabs of the subfamily Ocypodinae. They are common shore crabs in tropical and subtropical regions throughout the world, inhabiting deep burrows in the intertidal zone. They are generalist scavengers and predators of small animals. The name "ghost crab" derives from their nocturnality and their generally pale coloration. They are also sometimes called sand crabs, though the name refers to various other crabs that do not belong to the subfamily.
The genus Coenobita contains 17 species of terrestrial hermit crabs. Several species in this genus are kept as pets.
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 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.
Geosesarma is genus of small freshwater or terrestrial crabs, typically less than 10 mm (0.4 in) across the carapace. They live and reproduce on land with the larval stages inside the egg. They are found from India, through Southeast Asia, to the Solomon Islands and Hawaii.
Gecarcinus lateralis, also known by the common names blackback land crab, Bermuda land crab, red land crab and moon crab, is a colourful crab from the family Gecarcinidae.
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 west 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.
Potamon is a genus of freshwater or semiterrestrial crabs mainly found from Southern Europe through the Middle East, and as far east as north-western India. The only exception is the North African P. algeriense, which also is the only potamid of mainland Africa. Twenty species are currently recognised. These crabs are omnivores that have a broad ecological tolerance. The adult Potaman reach up to 50 mm in size during their 10-12 year life span.
Guinotia is a monotypic genus of freshwater crabs in the family Pseudothelphusidae, containing only the species Guinotia dentata, commonly known as cyrique. They have few predators. Found in the West Indies, they are easily caught and thus are used locally as a food source.
Afruca tangeri is a species of fiddler crab that lives along the Atlantic coasts of western Africa and southwestern Europe.
Around 1,300 species of freshwater crabs are distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs, which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas. As a result, a large proportion are threatened with extinction.
Johngarthia weileri is a species of land crab in the genus Johngarthia from the eastern Atlantic Ocean.
Coenobita scaevola is a species of terrestrial hermit crab from the western Indian Ocean and Red Sea.
In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water, or land animals that have spent at least one life stages in aquatic environments. When referring to plants, the term describes land plants whose roots have adapted well to tolerate regular, prolonged submersion in water, as well as emergent and (occasionally) floating-leaved aquatic plants that are only partially immersed in water.
Red Devil Vampire Crabs are decapod crustaceans part of Brachyura. They are land living, freshwater crabs from tropical areas and are endemic to Indonesia. Like all other crabs, they have a carapace, two chelae and ten jointed legs. They are omnivorous.
Geosesarma dennerle is a species of small land-living crabs found on Java, Indonesia.
Coenobita rubescens is a species of terrestrial (land-living) hermit crab, family Coenobitidae.
Nanhaipotamon is a genus of freshwater crabs, in the subfamily Potamiscinae, found in southern China and Taiwan. As of 2018, 18 species have been described. The genus is named after the South China Sea, for it occurs mostly in coastal areas. The genus was first described by R. Bott in 1968 as Isolapotamon (Nanhaipotamon), i.e., a subgenus of Isolapotamon.
Nanhaipotamon hongkongense is a species of freshwater crab of the genus Nanhaipotamon, known to occur in Hong Kong and adjacent areas in Shenzhen and Dongguan, Mainland China.
Nanhaipotamon macau, the Coloane hill crab, is a species of freshwater crab found solely in twelve hill streams on the island of Coloane in Macao. A member of the genus Nanhaipotamon, it was first described in December 2018 and is closely related to other land crabs such as Nanhaipotamon hongkongense.