''Ocypode'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

ghost crab 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 predator ...

s found in the sandy shores of

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

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

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 or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

. They are primarily

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

, and are generalist

scavenger Scavengers are animals that consume Corpse decomposition, 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 he ...

s and

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s of small animals. The genus contains 21

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

Taxonomy

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

entomologist Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...

Friedrich Weber in 1795, using the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

'' Cancer ceratophthalmus'' described by the German

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Peter Simon Pallas Peter Simon Pallas Fellow of the Royal Society, FRS FRSE (22 September 1741 – 8 September 1811) was a Prussia, Prussian zoologist, botanist, Ethnography, ethnographer, Exploration, explorer, Geography, geographer, Geology, geologist, Natura ...

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 predators ...

until 2013, when Katsushi Sakai and Michael Türkay reclassified the gulf ghost crab into a separate genus, '' Hoplocypode''. It belongs to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Ocypodidae The Ocypodidae is a family of semiterrestrial crabs that includes ghost crabs and fiddler crabs. These crabs are found along tropical and temperate shorelines worldwide. Some genera previously classified within the Ocypodidae family have been r ...

. 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 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 tortoises, the unde ...

are usually not clearly defined. They have thick and elongated eyestalks with the

cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

occupying most of the lower portion. The eyestalks are also tipped with horn-like projections (styles) in seven species ('' Ocypode brevicornis'', '' 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. 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 (

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

s) 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 anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these m ...

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 environm ...

areas. They are

and are generalist

s and

s of small animals.

Distribution

''Ocypode'' ghost crabs are found in

and

regions throughout the world. Three species are found in the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

and the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

and one in the eastern

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

coast of the Americas. The rest of the species are found in the western Pacific and the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

to the tip of southern

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Species

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

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 Saint John's Island ( ), also known as St John's, is an island in the Straits of Singapore located 6.5 km off the southern coast of Singapore. With an area of , it is the largest of the Sisters' Islands Marine Park, Marine Park islands wh ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

{{Taxonbar, from=Q13908705 Ocypodoidea Decapod genera