| Selatium | |
|---|---|
 | |
| Image of mangrove crab, selatium brockii. [1] | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Sesarmidae |
| Genus: | Selatium Serène & Soh, 1970 |
Selatium is a genus of crabs in the family Sesarmidae.
Selatium, or mangrove crabs, grow to around 2 cm - 2.5 cm in size, and have a distinct patterning on their dorsal side. [1] Their legs and carapace display a striped pattern. [1] The carapace itself is flat and square-shaped. [1] It is wider than it is long and has deep grooves along the surface that separate each region. [1] A large, sharp tooth is present on the carapace near the eyes. [1] Selatium morphology also consists of chelipeds, or the front pair of extremities that attach to large claws or fingers. [1] The tips of their chelipeds are cupped to facilitate feeding on algae and have sharp edges used for cutting. [1] This species does not exhibit sexual size dimorphism, however, on the dorsal side of their claw, males have a row of small, narrow teeth, while females have tubercles. [1] Mangrove crabs also have four other pairs of legs used for movement. [1] Their legs have long propodi (second most distal segment) and short dactyli (most distal segment). [1] On the underside of the carapace lies the abdomen which is triangular in shape with a rounded telson. [1]
Mangrove crabs are most commonly found in the Indo-Pacific ranging from northern Australia to India and the eastern coast of Africa. [1] They tend to live within the sandbank regions of mangroves. [2] Known to climb trees instead of burrowing, they can be found between 1.5m to 3.0m from the ground, usually residing in hollow trees and holes in tree trunks during the day. [2] Sometimes they can be found hiding under fallen tree bark or other organic matter. [1] Selatium are nocturnal to reduce the risk of predation and avoid desiccation. [1] At night, they feed on algae that grows on the lower portion of tree trunks. [1]
Selatium primarily feed on algae, however, they are opportunistic omnivores and at times will feed on vegetation or insects. [1] Rotting leaves are important supplemental sources of nutrients for mangrove crabs. [3] Selatium will occasionally hunt prey with higher protein contents to obtain missing nutrients such as nitrogen. [3] When feeding, mangrove crabs will use their chelipeds to slice food into smaller fragments which they then grind down by the mandibles and gastric mill in their abdomen. [1]
Mangrove crabs often partake in intraspecific competition for limited resources such as food, habitat space, and mates. [4] During the breeding season, crabs will fight any other male, regardless of size in order to mate with their chosen female. [5] Fights consist of a series of lunges and jabs with the crab's chelae. [1] Crabs have been found to form clusters of both males and females, using density as a way to avoid predation. [4] Within these clusters, the largest males patrol the area for predators while the smaller males and females inhabit the surrounding area. [4] Mangrove crabs are not known to travel far in search of food or mating opportunities. [4]
Following fertilization, female crabs carry eggs on their abdomen during their early stages of development. [1] When they hatch, the eggs are released into the water where they will undergo five stages of juvenile development, four zoeal stages and 1 megalopa stage. [6] During all zoeal stages, the larvae live in brackish waters. [6] During these stages, the crabs use appendages stemming from the thorax to swim and will also have a large dorsal spine. [7] Crabs in the megalopa stage also live in brackish waters, but here they have a segmented abdomen, meaning their legs will no longer stem from the abdominal area. [7] Because of this, they have an unsegmented cephalothorax in which the legs will stem from. [7] In this stage the eyes and antennae will form. After the megalopa stage, mangrove crabs have reached adulthood. Once adults, they will molt multiple times in order to reach their adult size. [1]
The Japanese spider crab is a species of marine crab and is the biggest one that lives in the waters around Japan. At around 3.7 meters, it has the largest leg-span of any arthropod. The Japanese name for this species is taka-ashi-gani,, literally translating to “tall legs crab”. It goes through three main larval stages along with a prezoeal stage to grow to its great size.
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.
Hemigrapsus crenulatus, the hairy-handed crab or papaka huruhuru, is a marine crab of the family Varunidae, endemic to the New Zealand coast, although a taxon in Chile may be conspecific. It is an intertidal species with semi-terrestrial tendencies. They are named by their characteristic setae, or patches of thick hair, on the chelipeds and legs. They can range from green to brown in coloration. Adult crabs are generally 2–4 cm (0.8–1.6 in) wide at the carapace, although the smallest mature crabs can be around just 1 cm (0.4 in) wide. and are able to survive and reproduce in environments of widely varying salinities.
The Smooth Shore Crab is a marine large-eyed crab of the family Grapsidae, found in New Zealand and the Juan Fernández Islands of Chile.
Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.
Latreilliidae is a small family of crabs. They are relatively small, long-legged crabs found on soft bottoms at depths of up 700 metres (2,300 ft) in mostly tropical and subtemperate waters around the world. Their carapace is very small and doesn’t cover the bases of their legs, which protrude from the cephalothorax in a spider-like manner. The family and its type genus are named after Pierre André Latreille. The oldest known fossils from the Latreillidae have been dated to the middle of the Cretaceous period. It comprises seven extant species.
The purple shore crab is a common crab of the family Varunidae that is indigenous to the west coast of United States, Canada, and Mexico. H. nudus was first described in 1847 by Adam White, and in 1851, James Dwight Dana formally classified the species. H. nudus is a small, amphibious crab that is similar physically and behaviorally to Pachygrapsus crassipes and Hemigrapsus oregonensis. The purple shore crab is generally a dark purple color with olive green, red, and white spots. Mating season for H. nudus begins in mid-winter and larval crabs undergo 5 zoeal stages and a juvenile stage. Adult crabs mainly feed on algae but will occasionally scavenge other animals. H. nudus prefers inter-tidal and sub-tidal zones, and it can oftentimes be found sheltering under rocks or other debris. H. nudus demonstrates complex compensatory mechanisms to counteract fluctuating salinity and water oxygen concentrations, permitting it to live in a variety of different environments.
Hemigrapsus oregonensis is a small shore crab of the family Varunidae; formerly classified under the family Grapsidae. It is known under several common names, including yellow shore crab, hairy shore crab, green shore crab, mud-flat crab, bay shore crab and Oregon shore crab. Despite its common name, the crab actually has a wide variety of coloration. It is found along the West Coast of the United States and Canada, specifically along shorelines and similar geographical areas. In 2009, H. oregonensis was included on a list of animals petitioning for the endangered species label, but there was not enough scientific information available for it to be considered as such, so it remains unevaluated to the present day.
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.
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.
Pisidia longicornis, the long-clawed porcelain crab, is a species of porcelain crab that lives in the north-eastern Atlantic Ocean. It varies from reddish to white, and grows to a carapace width of 1 cm (0.4 in). It was first named by Carl Linnaeus in 1767, although the etymology remains unclear.
Guinotellus melvillensis is a species of crabs in the family Xanthidae, the only species in the genus Guinotellus. It is a benthic crab with an ovate carapace within the subfamily Euxanthinae.
Oregonia gracilis, commonly known as the graceful decorator crab, is a species of crab belonging to the family Oregoniidae. Like other decorator crabs it habitually attaches other organisms to its back. The sessile organisms are attached to hooked setae that act as a sort of velcro attachment. This decoration provides visual and chemical camouflage thus reducing predation risk. Pacific halibut are a major predator of O. gracilis. Other predators include octopus and sea otters. The main food source of O. gracilis is floating kelp and algae that they capture utilizing a waiting strategy in order to maintain cryptosis.
Pyromaia tuberculata is a species of crab in the family Inachoididae.
The violet vinegar crab is a swimming crab species in the genus Episesarma. Distributed all over marine and brackish waters of Indo-West Pacific regions. It is harvested by many local fishermen for rich proteinaceous food.
Perisesarma guttatum, the red-claw mangrove crab, is a crab species in the genus Perisesarma and the family Sesarmidae. It is distributed in coastal brackish water habitats of the western Indian Ocean.
Thalamita crenata, the mangrove swimming crab, 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.
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 2017. It was the third species placed in the genus Haberma, which was described in 2002.
Latreillia elegans is a species of crab belonging to the family Latreilliidae. This family of crabs is identified by their appearance as small, long-legged crabs. The species belongs to the genus Latreillia which has only five identified species: L. elegans, L. metanesa, L. williamsi, L.valida, and L. pennifera. It was previously thought that L. elegans and L. mannengi were two separate species, but it has since been revealed that the two species are synonymous. All the thought to be differences between L. elegans and L. mannengi were in actuality overlaps. The L. mannengi is simply referring to the close relative to the species of L. elegans found in the western Atlantic.
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.
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