| Libinia emarginata | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Epialtidae |
| Genus: | Libinia |
| Species: | L. emarginata |
| Binomial name | |
| Libinia emarginata | |
| Synonyms [2] | |
Libinia canaliculataSay, 1817 | |
Libinia emarginata, the portly spider crab, common spider crab or nine-spined spider crab, is a species of stenohaline crab that lives on the Atlantic coast of North America.
Libinia emarginata occurs from Nova Scotia to the Florida Keys and through the Gulf of Mexico. [3] It lives at depths of up to 160 ft (49 m), with exceptional records of up to 400 ft (120 m). [4]
Libinia emarginata is roughly triangular in outline and very heavily calcified, with a carapace about 4 in (100 mm) long and a leg span of 12 inches (300 mm). [4] The whole crab is khaki, and the carapace is covered in spines and tubercles, [5] and, as with other decorator crabs, often clothes itself in debris and small invertebrates. [4]
Mating takes place, and eggs are produced from June to September. The eggs are initially a bright orange-red, but turn brown during development, which takes around 25 days. The eggs then hatch as zoea larvae, and the female can produce another brood of eggs within 12 hours, unlike many other crab species whose females only mate immediately after molting. [6]
Libinia emarginata is very similar to Libinia dubia with which it is largely sympatric. They can be told apart by examining the row of spines along the center of the carapace: in L. emarginata there are nine, while in L. dubia there are only six. [5] Also, the rostrum of L. dubia is more deeply forked than that of L. emarginata. [4]
Libinia emarginata lives on various substrates, at depths of up to 150 ft (46 m). Adults are sluggish and not aggressive, and younger crabs are frequently covered with sponges and hydroids. [5]
Despite its small size, in comparison to other predatory crabs, L. emarginata feeds on large starfish such as Asterias forbesi . [7]
Unusually for crabs, L. emarginata preferentially walks forwards, rather than sideways, although they are also capable of sidelong movement. [8] Its skeletal, [9] muscular [8] and neural anatomy [10] more closely resembles that of forward-walking species, rather than that of more closely related sideways-walking species.
L. emarginata will mate in large aggregations. [11] These aggregations may function as a protective mechanism during reproduction. [11] Males of L. emarginata show an unusual "obstetrical behavior", in which gravid females who are about to release their larvae are held behind the male and aggressively protected. [6]
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The Japanese spider crab is a species of marine crab that lives in the waters around Japan. It has the largest known 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.
Stenorhynchus seticornis, the yellowline arrow crab or simply arrow crab, is a species of marine crab.
Libinia is a genus of crabs in the family Epialtidae, containing twelve extant species:
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Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.
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Dromia personata, also known as the sponge crab or sleepy crab, is a species of crab found in the North Sea, the Mediterranean Sea, and connecting parts of the northeastern Atlantic Ocean. Like most other epibenthic crustaceans, the biomass of this species is especially dense in the Mediterranean continental shelf. It mainly resides from the lower shore to a depth of 50 meters (164 ft), often in caves. Occasionally, they are found living in depths as low as 110 meters (360 ft). They serve as prey for octopus, starfish, and other fish. Their last two pairs of legs are positioned dorsally, and are used to hold a sponge in place as camouflage.
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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.
Xantho hydrophilus, the furrowed crab or Montagu's crab, is a species of crab from the family Xanthidae. It is yellowish-brown and grows to a carapace width of 70 mm (2.8 in). It is a nocturnal omnivore that lives in shallow marine waters from western Scotland to the Cape Verde Islands.
Inachus phalangium, Leach's spider crab, is a species of crabs from the north-eastern Atlantic Ocean and Mediterranean Sea. It is up to 20.5 mm (0.81 in) wide, and is very similar to other species in the genus Inachus.
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.
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Libinia ferreirae is a species of tropical spider crab in the family Epialtidae. It is found on the seabed in shallow waters off the Atlantic coast of South America.
Pyromaia tuberculata is a species of crab in the family Inachoididae.
Hepatus pudibundus, the flecked box crab, is a crab from the class Malacostraca. They are found in the Atlantic Ocean with Brazil having a dense population of H. pudibundus, as they are one of the most commonly seen crabs in the country. Many of the studies done on H. pudibubus have occurred in the Ubatuba region of Brazil, where there is a rapid expansion of tourism that is affecting marine ecosystems.
Libinia spinosa is a majoid crab found in mud and sand bottoms of the Southwestern Atlantic and Pacific oceans. It is a generalist feeder on organisms such as algae, sponges, cnidarians, mollusks, polychaetes, crustaceans, and small fish. It commonly engages in a symbiotic relationship with the medusa Lychnorhiza lucerna.
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