''Ocypode'' is a genus of ghost crabs found in the sandy shores 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 ...

regions throughout the world. They have a box-like body, thick and elongated eyestalks, and one claw is larger than the other in both males and females. They inhabit deep burrows in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

. They are primarily

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

, and are

generalist A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to: Occupations * a physician who provides general health care, as opposed to a medical specialist; see also: ** General pract ...

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

s and predators of small animals. The genus contains 21 species.

Taxonomy

The genus ''Ocypode'' was first established by the German

entomologist Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...

Friedrich Weber in 1795, using the type species '' Cancer ceratophthalmus'' described by the German naturalist Peter Simon Pallas in 1772. ''Ocypode'' was previously the only genus classified under the ghost crab subfamily

Ocypodinae 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 preda ...

until 2013, when Katsushi Sakai and Michael Türkay reclassified the

gulf ghost crab The gulf ghost crab, ''Hoplocypode occidentalis'', is a species of ghost crabs native to the Pacific coast of the Americas, from the Gulf of California to Colombia. It is the only species in the genus ''Hoplocypode''. Gulf ghost crabs are medium- ...

into a separate genus, ''

Hoplocypode The gulf ghost crab, ''Hoplocypode occidentalis'', is a species of ghost crabs native to the Pacific coast of the Americas, from the Gulf of California to Colombia. It is the only species in the genus ''Hoplocypode''. Gulf ghost crabs are medium ...

''. It belongs to the family Ocypodidae. Ghost crabs of the genus ''Hoplocypode'' can be distinguished from those in ''Ocypode'' by examining their gonopods. In the former, the first gonopod has a complex hoof-shaped tip, while in the latter they are simple and curved.

Description

''Ocypode'' ghost crabs have deep box-like bodies. The regions on the

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 ...

are usually not clearly defined. They have thick and elongated eyestalks with the cornea occupying most of the lower portion. The eyestalks are also tipped with horn-like projections (styles) in seven species (''

Ocypode brevicornis ''Ocypode brevicornis'' is a species of ghost crab native to the Indian Ocean, from the Gulf of Oman to the Nicobar Islands. They are relatively large ghost crabs with a somewhat trapezoidal body. The carapace reaches a length of and a width ...

'', '' O. ceratophthalma'', '' O. gaudichaudii'', '' O. macrocera'', '' O. mortoni'', '' O. rotundata'', and '' O. saratan''). Though these may be shorter or even absent altogether in juvenile specimens. While in '' O. cursor'' the eyestalks are tipped with a tuft of bristles (setae). The eyestalks are held vertically when the crab is active. Most species have pale-colored bodies that blend in well with the sand, though they are capable of gradually changing body coloration to match their environment and the time of day. The claw-bearing legs ( chelipeds) of both sexes are unequal in size, with one much larger than the other. The palm of the claws also possess

stridulating Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...

(sound-producing) ridges which they use for communication. These ridges are also important morphological characters useful for identifying species. The chelipeds are shorter than the walking legs. The last pair of walking legs (

pereiopod The decapod (crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various g ...

s) is also usually shorter and thinner than the other pairs of walking legs. A cavity, with edges fringed by long setae are also found in between the bases of the second and third walking legs.

Ecology

''Ocypode'' ghost crabs construct simple to complex deep burrows in soft sandy and/or muddy substrates. They can be found in sandy beaches, rubble flats, and in

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

areas. They are

and are

s and predators of small animals.

Distribution

''Ocypode'' ghost crabs are found in tropical and

regions throughout the world. Three species are found in the Atlantic Ocean and the Mediterranean Sea and one in the eastern Pacific coast of the Americas. The rest of the species are found in the western Pacific and the Indian Ocean to the tip of southern Africa.

Species

''Ocypode'' currently contains 21 valid species. The ghost crab formerly known as '' O. occidentalis'' was transferred to its own genus ''

'' in 2013. ''O. longicornuta'', ''O. platytarsis'', ''O. pygoides'' and ''O. sinensis'' were determined to be

synonyms 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 ''O. ceratophthalma'', ''O. brevicornis'', ''O. convexa'' and ''O. cordimanus'' respectively.

References

External links

Video
of ''Ocypode ceratophthalma'' eating a moon crab in Saint John's Island, Singapore {{Taxonbar, from=Q13908705 Ocypodoidea