| Violet vinegar crab | |
|---|---|
 | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Subphylum: | |
| Class: | |
| Order: | |
| Infraorder: | |
| Family: | |
| Genus: | |
| Species: | E. versicolor |
| Binomial name | |
| Episesarma versicolor (Tweedie, 1940) | |
| Synonyms | |
| |
The violet vinegar crab (Episesarma versicolor) is a swimming crab species in the genus Episesarma . [2] Distributed all over marine and brackish waters of Indo-West Pacific regions. It is harvested by many local fishermen for rich proteinaceous food.
A mangrove inhabitant, it is found all over Southeast Asian countries such as Southern China, Hong Kong, Indonesia, Malaysia, Philippines, Singapore, Thailand, northern Australia and South Asian countries like Bangladesh, India and Sri Lanka. [3] They also seem to possess an estimate of around 40 bony spine-like structures called tubercles. These are more pronounced in males and these tubercles like in other crab species that have them seemingly represent stridulatory organs used to create sound. [4]
The genus Episesarma comprises some of the largest sesarmid crabs. E. versicolor is distinguished by its white tipped violet chela (claw). [5] Males grow up to a maximum length of 5 cm. The carapace is square-shaped and relatively flat, colored brown to brownish grey. [6] The first gonopod of male E. versicolor has a narrower, shorter tip compared to other members of the genus. [7] The dorsal portion of the dactylus possess 65-80 densely packed projections called tubercles [5] These bony spine-like structures are more pronounced in males and, as seen in other crab species with tubercles, seem to be stridulatory organs for generating sound. [4]
Like most crabs they possess both male and female sexes. A ritual is generally performed utilizing both olfactory and tactile cues followed by an indirect sperm transfer. [6]
This species is well distributed in mangrove regions, inhabiting burrows at tree bases or sometimes mounds created by Thalassina lobsters. [3] Comparatively, mangroves have a high degree of biodiversity and provide a niche specific to the crab that decreases interspecific competition for food and other resources. [8] E. versicolor favors the forest more than the Thalassina mound system in comparison to other species in the Episesarma genus. [9]
Episesarma versicolor are omnivorous, but feed primarily on calyx and leaves of water plants, mangroves, and mangrove associates. [3] At Segara Anakan Lagoon, Java, Indonesia, E. versicolor feed on various food sources including detritus, bark, leaves, and on roots, algae and animal matter to a lesser extent. Their diet adapts to the environment, which helps them survive when food sources are scarce or changing. When food is abundant, such as during a feeding experiment, they prefer leaves with a high amount of nitrogen compounds. [10] They have been observed cutting leaf litter and bringing some fragments back to their burrows. [11] To remove leaves from trees, they tear off a section of the leaf with their claws and feed on those small sections they tear off. Leaves with previous damage from other herbivorous organisms are targeted by the crabs for feeding, utilizing previous holes to tear off sections more easily. [12]
E. versicolor burrow when the tide is low in day time, unless heavy rainfall forces them out of the burrows. When the tide is high, the larger crabs climb up trees, while smaller crabs stay burrowed. [9] They can climb as high as 6m up. [3] The crabs do not feed while they stay up on the trees, which indicates that they migrate to avoid predators during high tide. Predators such as fish and hard-shelled crabs can enter the larger burrows of E. versicolor, which forces larger individuals to climb up trees. However, while on the trees, E.versicolor are vulnerable to terrestrial predators and avoid detection by staying motionless on the tree trunks. [9]
Episesarma versicolor utilize three different sounds when communicating and competing with each other in the form of rapping, vibrating and leg stamping. Each form communicates a different message. Rapping is the action of repeatedly hitting their claws against the substrate. It is generally observed in displays of territory defense against other individuals. Leg stamping is when the leg repeatedly strikes against the substrate. Leg stamping has been observed when used to show dominance for mates or territory, even when the E. versicolor are fighting it is observed that they will still utilize leg stamping in their fights. Vibrating is the action of E. versicolor raising one of their legs and vibrating it in the air rapidly. This behavior is utilized by E. versicolor after competition between species resembling a victory dance against competition. [4]
E. versicolor is an important part of commercial fisheries in Southeast Asia. [13] They are harvested by hand and often pickled in vinegar and/or salt solutions to be eaten with rice or deep fried. [7] Due to their popularity in Thailand, they are being overfished. [13] 18,000 tons of sesarmid crabs like E. versicolor are harvested from mangrove habitats and are consumed by Thai people. 12,000 tons of crab harvested annually from the Thai mangroves cannot keep up with domestic demand. Hence, Thailand imports at least 6000 tons of sesarmid crabs from the neighboring countries of Myanmar and Cambodia. [14]
The fiddler crab or calling crab may be any of more than one hundred species of semiterrestrial marine crabs in the family Ocypodidae, well known for their sexually dimorphic claws; the males' major claw is much larger than the minor claw, while the females' claws are both the same size. A smaller number of ghost crab and mangrove crab species are also found in the family Ocypodidae. This entire group is composed of small crabs, the largest being slightly over two inches (5 cm) across. Fiddler crabs are found along sea beaches and brackish intertidal mud flats, lagoons, swamps, and various other types of brackish or salt-water wetlands.
Mangrove crabs are crabs that live in and around mangroves. They belong to many different species and families and have been shown to be ecologically significant by burying and consuming leaf litter. Mangrove crabs have a variety of phylogenies because mangrove crab is an umbrella term that encompasses many species of crabs. Two of the most common families are sesarmid and fiddler crabs. They are omnivorous and are predated on by a variety of mammals and fish. They are distributed widely throughout the globe on coasts where mangroves are located. Mangrove crabs have wide variety of ecological and biogeochemical impacts due to the biofilms that live in symbiosis with them as well as their burrowing habits. Like many other crustaceans, they are also a human food source and have been impacted by humans as well as climate change.
Scylla serrata is an ecologically important species of crab found in the estuaries and mangroves of Africa, Australia, and Asia. In their most common forms, their shell colours vary from a deep, mottled green to very dark brown.
Coenobita cavipes is a species of land hermit crab native to the eastern parts of Africa, the Indonesia, Philippines, China, Japan, Malaysia, Taiwan, Polynesia, and Micronesia. While these hermit crabs are terrestrial, they prefer to reside near the shores for access of both water and land.
The Grapsoidea are a superfamily of crabs; they are well known and contain many taxa which are terrestrial (land-living), semiterrestrial, or limnic. Another well-known member with a more conventional lifestyle is the Chinese mitten crab, Eriocheir sinensis.
Thalassina is a genus of mud lobsters found in the mangrove swamps of the Indian Ocean and western Pacific Ocean. Its nocturnal burrowing is important for the recycling of nutrients in the mangrove ecosystem, although it is sometimes considered a pest of fish and prawn farms.
The Sesarmidae are a family of crabs, previously included in the Grapsidae by many authors. Several species, namely in Geosesarma, Metopaulias, and Sesarma, are true terrestrial crabs. They do not need to return to the sea even for breeding.
Parasesarma pictum is a mudflat crab, belonging to the Sesarmidae family, which is endemic to East Asia. This crab typically inhabits mangrove swamps, preferring the upper intertidal region of estuaries, and living in small crevices and abandoned holes made by other species. It eats leaf litter and other vegetation. The breeding season of P. pictum is between May and September.
Aratus pisonii, commonly known as the mangrove tree crab, is a species of crab which lives in mangrove trees in tropical and subtropical parts of the Americas, from Florida to Brazil on the Atlantic coast. A.pacificus occurs from Nicaragua to Peru on the Pacific coast. A. pisoni feeds mostly on the leaves of the mangroves, but is an omnivore, and prefers animal matter when possible. A. pisonii and A. pacificus are the two species in the genus Aratus. The specific epithet pisonii commemorates the Dutch naturalist Willem Piso who travelled in Brazil in 1638 with Georg Marggraf.
The mangroves of the Straits of Malacca are found along the coast of Thailand, Malaysia, Singapore and northern Sumatra. These tropical mangrove forests are highly diverse, and are important wetlands with high conservation values. There are two Ramsar sites along the Strait of Malacca: Pulau Kukup and Tanjung Piai.
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.
Ucides cordatus, the swamp ghost crab, is one of two species of crabs in the genus Ucides. This species of crab is native to many coasts off of the western Atlantic Ocean. It has been found to be native to areas as far as Florida, to as southern as Uruguay. U. cordatus is especially noteworthy in the country in Brazil as it plays important roles in the economy and food resources at Brazil’s Atlantic borders.
Parasesarma leptosoma, also known as the arboreal crab, is an arboreal, leaf-eating mangrove crab, from East and South Africa where it is found on Rhizophora mucronata and Bruguiera gymnorhiza, but not on Avicennia marina. It occupies an ecological niche similar to that of another sesarmid, Aratus pisonii, from the Americas.
Geosesarma dennerle is a species of small land-living crabs found on Java, Indonesia.
The mangrove swimming crab, also called the crenate swimming crab or spiny rock crab, is a swimming crab species in the genus Thalamita. Distributed all over marine and brackish waters of Indo-West Pacific regions. It is widely used as an edible crab in many countries.
The Micro Mangrove Crab (Haberma tingkok) is a species of micro-mangrove crab native to Hong Kong. It was first discovered by Stefano Cannicci from the University of Hong Kong and Peter Ng from the University of Singapore in the Ting Kok Mangrove forests in the northeast of Hong Kong and listed on the World Register of Marine Species (WoRMS) in April of 2017. It was the third species placed in the genus Haberma, which was discovered in 2002.
Thalassina anomala, known as the scorpion mud lobster, is a species of crustacean in the family Thalassinidae.
Armases cinereum, also known as the squareback marsh crab or wharf crab, is a species of crab in the family Sesarmidae. The wharf crab is a small crab that is dark brown to muddy in color, which allows it to blend in with its usual surroundings. It is found on the Atlantic southeastern coast, down into the Gulf of Mexico. It is an omnivore and is prevalent in marshy coastal environments along the Southwestern Atlantic.
 | This crab article is a stub. You can help Wikipedia by expanding it. |