''Calappa hepatica'', the reef box crab, is a common

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

species of

box crab A box ( plural: boxes) is a container used for the storage or transportation of its contents. Most boxes have flat, parallel, rectangular sides. Boxes can be very small (like a matchbox) or very large (like a shipping box for furniture), and ...

of tropical and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

parts of the Indian and Pacific Oceans and the Red Sea.

Description

''Calappa hepatica'' grows to a

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

width of about ; the length is always less than two thirds of its width. The posterior portion of the shell has broad extensions with several blunt teeth on the margin, and these largely conceal the walking legs. The carapace and the exposed parts of the

chelae A chela ()also called a claw, nipper, or pinceris a pincer-like organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through New Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds. ...

(pincers) are a mottled greyish-brown colour, and are covered with small raised tubercles of various sizes, making the crabs well-camouflaged when semi-submerged in the sand. The chelae are large and powerful, and specially adapted to the crab's feeding behaviour, the crushing and eating of molluscs.

Distribution and habitat

''Calappa hepatica'' is found in the tropical and subtropical Indo-Pacific region, its range extending from the Red Sea to Hawaii,

French Polynesia )Territorial motto: ( en, "Great Tahiti of the Golden Haze") , anthem = , song_type = Regional anthem , song = " Ia Ora 'O Tahiti Nui" , image_map = French Polynesia on the globe (French Polynesia centered).svg , map_alt = Location of Frenc ...

, Cocos Island and northern Australia. Its typical habitat is on the sandy or shelly sand seabed, often in reef habitats, and seagrass meadows, at depths down to about .

Ecology

During the day, ''Calappa hepatica'' remains buried in sand with only the area round the eyes protruding. It emerges at night to hunt for prey, and can rebury itself in the substrate efficiently and fast if danger threatens. It is a predator, and largely feeds on

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

and

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

molluscs, as well as hermit crabs. It has a specially adapted right chela which it uses to break open the shell of its prey; for this purpose it has a large accessory tooth located at the base of the hinged part of the claw, which is located opposite a flat plate on the fixed part, the two working together like a vice. After breaking open the shell, it uses its left pincer, which is longer and more pointed than the right, to pick out the soft tissues. Calappe_sandwichien.png, Illustration of ''Calappa sandwichien'' made in 1852, a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of ''C. hepatica'' Calappa hepatica (MNHN-IU-2010-5033).jpeg, Preserved specimen Calappa hepatica (MNHN-IU-2013-2016).jpeg, Both of these specimens belong to the collection of the Museé National D'Histoire Naturelle (MNHN)

References

External links

* {{Taxonbar, from=Q3934032 Calappoidea Crustaceans of the Indian Ocean Crustaceans of the Pacific Ocean Crustaceans described in 1758 Taxa named by Carl Linnaeus