Ocypode is a genus of ghost crabs found in the sandy shores of tropical and subtropical 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. They are primarily nocturnal, and are generalistscavengers and predators of small animals. The genus contains 21 species.
Ocypode was previously the only genus classified under the ghost crab subfamily Ocypodinae until 2013, when Katsushi Sakai and Michael Türkay reclassified the gulf ghost crab into a separate genus, Hoplocypode. It belongs to the familyOcypodidae. 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.[2]
Description
Ocypode ghost crabs have deep box-like bodies. The regions on the carapace 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, 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.[2][4] Most species have pale-colored bodies that blend in well with the sand,[5] though they are capable of gradually changing body coloration to match their environment and the time of day.[6][7]
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 (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 (pereiopods) 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.[2][4]
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 areas. They are nocturnal and are generalistscavengers and predators of small animals.[4][8]
Distribution
Ocypode ghost crabs are found in tropical and subtropical regions throughout the world.[9] 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.[2]
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 of O. ceratophthalma, O. brevicornis, O. convexa and O. cordimanus respectively.[2]
Medium-sized species found in the eastern Atlantic coast of Africa from Mauritania to Namibia. It is sympatric with O. cursor but can easily be distinguished from the latter by the absence of the tuft of bristles on the tip of their eyes.[2]
Large-sized species found in Oman, India, Sri Lanka, and the Nicobar Islands. They can be distinguished from other species of Ocypode in the Indian Ocean by the naked propodi of their first and second pair of walking legs and by the 23 to 28 tubercles on their stridulating ridge. Their eyestalks possess styles.[2]
Medium to large-sized species. They are one of the most widespread species in Ocypode, being found in the entirety of the Indian Ocean (except the Red Sea); and eastwards toward Polynesia and Clipperton Island, though they are not known from the eastern Pacific coast of the Americas. Their eyestalks possess styles, and they are frequently confused with similar species which share their distribution range (especially juveniles). They can be distinguished by a stridulating ridge of 10 to 11 interspaced tubercles on the upper third, 8 thick striae on the central third, and 20 to 30 closely spaced tubercles on the lower third; as well as by their slender gonopod with a palp, and the pointed tip of their smaller claw.[2]
golden ghost crab,[13][14] western ghost crab,[15] or yellow ghost crab[16]
Large-sized species found in Western Australia, from Broome to Perth. They can be distinguished by the forward-facing triangular outer edges of their eye orbits, pointed smaller claws, a stridulating ridge of 19 to 24 tubercles, and a fringe of bristles on the upper margin of the propodi of the first and second walking legs.[2]
Medium-sized species. They are one of the most widespread species in Ocypode, being found in the western Indian Ocean (including the Red Sea) to the French Polynesia in the western Pacific. As their common name implies, they can be distinguished by the absence of stridulating ridges on the palm of their claws.[2]
Large-sized species found in the eastern Atlantic, from Mauritania to Namibia; as well as the Mediterranean Sea, from Egypt to southern Greece. They are easily distinguished by the characteristic tuft of bristles on the end of their eyestalks.[2]
Medium-sized species found in Northern and Western Australia, from Darwin to Shark Bay. They closely resemble O. jousseaumei, but they are not found from the same localities.[2]
Medium to large-sized species found in the eastern Pacific coast of the Americas, from Guatemala to Chile. They share their distribution range with Hoplocypode occidentalis but are easily distinguishable by their bright coloration and the presence of styles on their eyestalks.[2]
Small to medium-sized species found only in the Gulf of Aden and the Gulf of Oman. They are very similar to O. fabricii, but they are not found in the same localities.[2]
Medium to large-sized species found in the Nicobar Islands, southern Thailand, Indonesia, and Papua New Guinea. They can be distinguished by a stridulating ridge of about 10 interspaced tubercles. The propodi of their first to fourth pair of walking legs do not possess bristles on the upper and lower surfaces.[2]
Medium-sized species found in Pakistan, India (including the Nicobar Islands), Sri Lanka, and Myanmar. In adult males, the outer edges of the eye orbits are tooth-shaped and project forward. The palm of the claws are densely covered with tubercles on the upper surface, with distinctively serrated upper and lower margins. The stridulating ridge has 35 to 56 tubercles with striae. The tip of the smaller claw is characteristically blunt. Their eyestalks possess styles.[2]
Medium-sized species found in Madagascar and the southeastern coast of Africa (from Mozambique to Natal, South Africa). Its carapace is covered densely with rough tubercles on the upper surface and wider than it is long. The outer edges of the eye orbits are broadly triangular and project forward. Their stridulating ridge has 20 to 30 tubercles.[2]
Small-sized species found in South China and southern Japan. It is closely related to O. stimpsoni which is also found in the same regions, but can be distinguished by the presence of styles on their eyestalks. They also share the same range with O. ceratophthalmus (which also possess styles), but O. mortoni have 35 to 71 striae on their stridulating ridges and their smaller claws have broadly rounded to flattened tips.[2]
Small-sized species found in the Gulf of Thailand, and the Malaysian Peninsula to northern Borneo. They are very similar to O. stimpsoni but they do not share the same distribution range.[2]
Small to medium-sized species. They are one of the most widespread species in Ocypode, being found from Hawaii to the Great Barrier Reef to Madagascar and Mauritius. It has been proposed that this species may actually be composed of two cryptic species, but it remains unclear without further molecular genetic tests. Their stridulating ridges are composed of 30 to 42 thick striae in males and 17 to 29 in females. The smaller claw is pointed.[2]
Medium to large-sized species found in the western Atlantic, from Massachusetts in the United States to Rio Grande do Sul in Brazil. They are easily distinguished as they are the only species of Ocypode in the western Atlantic.[2]
Large-sized species found in the southern coast of the Arabian Peninsula to northern India (from Oman to Bombay), including the Persian Gulf. They are very similar to O. saratan but can be distinguished by having 10 to 15 irregularly spaced elongated tubercles with striae on their stridulating ridges and a thumb-like palp on their gonopods. Their eyestalks possess styles.[2]
Medium-sized species found in the east coast of Africa, from Abd al Kuri of southern Somalia to Port Elizabeth of South Africa, and also the Seychelles. They can easily be distinguished by the presence of a characteristic red band along the inner edges of their legs.[2]
Medium to large-sized species found in the Red Sea. Very common species in the Red Sea, and one of only two species known from there (O. cordimanus has also been recorded in the Red Sea, but only rarely). Also known from Madagascar through Indian Ocean to the Western Pacific. Their eyestalks possess styles.[2]
Small-sized species found in China, the Korean Peninsula, and Japan. They closely resemble O. mortoni but can easily be distinguished because they lack styles on their eyestalks.[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 Ocypodidae are a family of semiterrestrial crabs that includes the ghost crabs and fiddler crabs. They are found on tropical and temperate shorelines around the world.
Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.
Minuca pugnax, commonly known as the Atlantic marsh fiddler crab, is a species of fiddler crab that lives on north-western shores of the Atlantic Ocean.
Ocypode ceratophthalmus, the horned ghost crab or horn-eyed ghost crab, is a species of ghost crab. It lives in the Indo-Pacific region ; from the coast of East Africa to the Philippines and from Japan to the Great Barrier Reef. They also occur in the Pacific Islands to as far east as Polynesia and Clipperton Island. As their common name implies, O. ceratophthalmus possess eyestalks extending beyond the eyes into long points, which are longer in adults, and shorter in juveniles. The crabs have a box-shaped body, 6–8 centimetres (2.4–3.1 in) across the carapace, with a darker markings towards the rear in the shape of an H. The outer edges of the eye-sheaths are also sharp and broadly triangular and distinctly pointing sideways in larger individuals. O. ceratophthalmus can run at speeds of up to 2.1 metres per second (6.9 ft/s).
Mictyris longicarpus, the light-blue soldier crab, is a species of crab that lives on sandy beaches from the Bay of Bengal to Australia; with other members of the genus Mictyris, it is "one of the most loved crabs in Australia". Adults are 25 mm (1 in) across, white, with blue on their backs, and hold their claws vertically. They feed on detritus in the sand, leaving rounded pellets of discarded sand behind them. The males may form into large "armies" which traverse the beach at low tide, before the crabs dig into the sand to wait for the next low tide.
Ocypode gaudichaudii, also known as the painted ghost crab or cart driver crab, is a species of crab found on Pacific beaches from El Salvador to Chile as well as on the Galápagos Islands. The species was first described by Henri Milne-Edwards and Hippolyte Lucas in 1843.
Pagurus sinuatus is a large species of hermit crab found in Australia and the Kermadec Islands. It is red or orange in colour with coloured bands on the legs and patches on the body.
Oregonia is a genus of crabs, comprising two extant species and one fossil species: It is classified in the family Oregoniidae under the spider crab superfamily Majoidea.
Ocypode cursor, the tufted ghost crab, is a species of ghost crab found on sandy beaches along the coasts of the eastern Atlantic Ocean and eastern Mediterranean Sea.
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-sized, reaching a maximum overall body diameter of 6 in (15 cm). They are one of only two ghost crab species found in the eastern Pacific. However, gulf ghost crabs can easily be distinguished from painted ghost crabs by the absence of "horns" on their eyes.
Ocypode africana, commonly known as the African ghost crab, is a species of ghost crabs native to the eastern Atlantic coast of western Africa, from Mauritania to Namibia. They are medium-sized ghost crabs reaching carapace width of 3.4 cm (1.3 in). They can vary in coloration from pinkish to dark grey. They are one of only two ghost crab species found in the eastern Atlantic. However, African ghost crabs can easily be distinguished from tufted ghost crabs by the absence of long tufts of hair on the tip of their eyestalks.
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 41 mm (1.6 in) and a width of 50 mm (2.0 in). They are a mottled brown to yellow in coloration. Like other ghost crabs, one of their claws is much larger than the other. Their eyestalks are large and elongated, tipped with prolongations at the tip known as styles. They are common inhabitants of open sandy beaches, living in burrows in the intertidal zone.
Ocypode convexa, commonly known as the golden ghost crab, or alternatively the western ghost crab or yellow ghost crab, is a species of ghost crabs endemic to the coast of Western Australia, from Broome to Perth. They are relatively large ghost crabs, with a carapace growing up to 45 mm (1.8 in) long and 52 mm (2.0 in) wide. They are easily recognisable by their golden yellow colouration. Like other ghost crabs they have box-like bodies with unequally sized claws. They also have large eyestalks with the cornea occupying most of the bottom part.
Ocypode fabricii is a species of ghost crabs endemic to the coast of northern and western Australia, from Darwin to Shark Bay. They are medium-sized ghost crabs with a squarish body. The carapace reaches a length of 38 mm (1.5 in) and a width of 40 mm (1.6 in). Like other ghost crabs, one of their claws is much larger than the other. They live in burrows in the intertidal zones of the muddy to sandy beaches of mangrove forests.
Calcinus laevimanus is a species of hermit crab in the genus Calcinus found in the Indo-West Pacific region, the type locality being Hawaii. It is also known as the blue-eyed hermit crab, zebra hermit crab, dwarf zebra hermit crab, left-handed hermit crab, Hawaiian reef hermit and other similar names.
Ocypode macrocera, the red ghost crab, is a species of crab in the family Ocypodidae. It is a medium-sized species of Ocypode found in Pakistan, India, Sri Lanka, and Myanmar. In adult males, the outer edges of the eye orbits are tooth-shaped and project forward. The palm of the claws are densely covered with tubercles on the upper surface, with distinctively serrated upper and lower margins. The stridulating ridge has 35 to 56 tubercles with striae. The tip of the smaller claw is characteristically blunt. Their eyestalks possess styles.
Ocypode mortoni is a small-sized species of Ocypode found in South China and southern Japan. It is closely related to O. stimpsoni which is also found in the same regions, but can be distinguished by the presence of styles on their eyestalks. They also share the same range with O. ceratophthalmus, but O. mortoni have 35 to 71 striae on their stridulating ridges and their smaller claws have broadly rounded to flattened tips.
Ocypode rotundata is a large-sized species of Ocypode found in the southern coast of the Arabian Peninsula to northern India, including the Persian Gulf. They are very similar to O. saratan but can be distinguished by having 10 to 15 irregularly spaced elongated tubercles with striae on their stridulating ridges and a thumb-like palp on their gonopods. Their eyestalks possess styles.
Ocypode saratan is a medium to large-sized species of Ocypode found in the Red Sea. Very common species in the Red Sea, and one of only two species known from there. Also known from Madagascar through Indian Ocean to the Western Pacific. Their eyestalks possess styles.
↑ Naturaliste Marine Discovery Centre. "Golden Ghost Crab". Government of Western Australia. Archived from the original on November 12, 2013. Retrieved November 12, 2013.
↑ "Ocypode cursor". SeaLifeBase. UBC - Canada. Archived from the original on September 24, 2015. Retrieved August 4, 2013.
↑ Thomas J. Trott (1988). "Note on the foraging activities of the painted ghost crab Ocypode gaudichaudii H. Milne Edwards & Lucas in Costa Rica (Decapoda, Brachyura)". Crustaceana. 55 (2): 217–219. doi:10.1163/156854088x00546. JSTOR20104392.
↑ Lynne Matthews (2007). The Coastal Guide of South Africa. Johannesburg, South Africa: Jacana Media. p.72. ISBN978-1-77009-248-8.
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