| Parapinnixa affinis | |
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| Species: | P. affinis |
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| Parapinnixa affinis | |
Parapinnixa affinis, the California Bay pea crab, is a species of pinnotherid crab endemic to Southern California. [1] It is a small crab that lives commensally in the tube of a tube-dwelling worm. It was one of the first marine crustaceans to be included on the IUCN Red List in 1996.
Parapinnixa affinis is similar to other pea crabs of the genus Parapinnixa , especially P. nitida . It differs from P. nitida in the proportions of its carapace, which is more than twice as wide as long in P. nitida but less than twice as wide as long in P. affinis. [3] The carapace is approximately 4.5 mm × 2.5 mm (0.177 in × 0.098 in) wide, with a maximum of 6.0 mm × 3.6 mm (0.24 in × 0.14 in). [4] The carapace is usually "light amber mottled with dark ochre", [4] but 5% of crabs are albino. [4]
Parapinnixa affinis appears to be endemic to Southern California, having been recorded from San Pedro, Anaheim Landing, Newport Bay and San Diego. [4] It was once recorded from Siberia, but this record is doubtful. [5]
Parapinnixa affinis was one of only two marine crustaceans to be included on the IUCN's list of endangered species in 1996, the other being the coconut crab. [6] Many others have been added later.
It lives commensally in the tubes of the polychaete worms Terebella californica and Loimia . [7] A bryozoan from the family Vesiculariidae is sometimes found on the legs of P. affinis. [4]
Parapinnixa affinis was first described by Samuel Jackson Holmes in 1900, in his Synopsis of California stalk-eyed Crustacea. The type specimen was a single female, collected in July 1895 from Dead Man's Island, San Pedro, California (now part of the Port of Los Angeles); it was donated to the University of California. [3] P. affinis no longer lives at the type locality, which has been made unsuitable by the accumulation of "harbor refuse and oil". [4] No further specimens were collected for over thirty years, until one was collected in 1930, and Steve Glassell collected specimens including an allotype in 1932. [4]
Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attacked, and use their large claws for maintaining territories. They first appeared in the Tithonian age of the Late Jurassic epoch, 145-152 million years ago.
Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width up to 25 centimetres and weigh up to 3 kilograms. C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred on the coasts of the British Isles, with more than 60,000 tonnes caught annually.
Metanephrops challengeri is a species of slim, pink lobster that lives around the coast of New Zealand. It is typically 13–18 cm (5–7 in) long and weighs around 100 g (3.5 oz). The carapace and abdomen are smooth, and adults are white with pink and brown markings and a conspicuous pair of long, slim claws. M. challengeri lives in burrows at depths of 140–640 m (460–2,100 ft) in a variety of sediments. Although individuals can live for up to 15 years, the species shows low fecundity, where small numbers of larvae hatch at an advanced stage.
The pea crab, Pinnotheres pisum, is a small crab in the family Pinnotheridae that lives as a parasite in oysters, clams, mussels, and other species of bivalves.
Ibacus peronii, the Balmain bug or butterfly fan lobster, is a species of slipper lobster. It lives in shallow waters around Australia and is the subject of small-scale fishery. It is a flattened, reddish brown animal, up to 23 cm (9 in) long and 14 cm (6 in) wide, with flattened antennae and no claws.
Parapinnixa is a genus of crab in the family Pinnotheridae. Originally described by Samuel Jackson Holmes as Pseudopinnixa, he published the replacement name Parapinnixa the following year, after learning of the senior homonym Pseudopinnixa Ortmann, 1894.
Pinnixa faba, known as the pea crab, mantle pea crab or large pea crab, is a pea crab which lives harmlessly within a large edible clam. This species is a symbiont of Tresus capax and Tresus nuttallii in its mature stage.
Periclimenes dardanicola is a species of shrimp found in the western Pacific Ocean. It lives in association with sea anemones that live on the gastropod shells carried by hermit crabs. It was first named by Alexander J. Bruce and Junji Okuno in 2006. It is mainly white, and grows up to a carapace length of 4 mm (0.16 in).
Hemigrapsus estellinensis is an extinct species of crab, formerly endemic to the Texas Panhandle. It was discovered by Gordon C. Creel in 1962 and was probably already extinct before his description was published in 1964, after the Estelline Salt Springs where it lived were contained by the United States Army Corps of Engineers. H. estellinensis is closely related to species from the Pacific Ocean such as Hemigrapsus oregonensis, but lived 800 km (500 mi) inland in a hypersaline spring. It differed from its relatives by the pattern of spots on its back, and by the relative sizes of its limbs.
Hapalogaster cavicauda is a species of king crab that lives on the Pacific coast of North America.
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.
Pinnixa chaetopterana, the tube pea crab, is a small decapod crustacean that lives harmlessly within the tube of the polychaete worm, Chaetopterus variopedatus.
Allopetrolisthes spinifrons is a species of porcelain crab. It displays "hypercarcinisation", whereby the resemblance to a true crab is enhanced by sexual dimorphism of the abdomen. It lives along the Pacific coast of Peru and Chile, as a symbiont of a sea anemone.
Pilumnoides inglei is a species of crab, known only from a few specimens collected on derelict boats on the south coast of England.
Oregonia bifurca, commonly known as the split-nose crab or the split-nose decorator crab, is a species of crabs belonging to the family Oregoniidae. It is a rare deep-water species that inhabits the tops of seamounts and guyots in the northeastern Pacific Ocean; from the Aleutian Islands, the Bering Sea, the Hawaiian–Emperor seamount chain, to the waters off British Columbia. It is closely related to the more common shallow-water species Oregonia gracilis, the graceful decorator crab.
Crustaceans form a large, diverse arthropod taxon which includes such animals as crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata; because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the clade Pancrustacea other than hexapods. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
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.
Labidochirus splendescens, commonly known as the splendid hermit crab, is a species of hermit crab found in the northeastern Pacific Ocean off the coast of North America. It is more heavily calcified and inhabits smaller mollusc shells than most hermit crabs.
Tunicotheres is a monotypic genus of crabs in the family Pinnotheridae, and Tunicotheres moseri is the only species in the genus. This crab lives commensally in the atrial chamber of a small ascidian. It is found in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Calyptraeotheres garthi is a species of pea crab in the family Pinnotheridae. It is found in the southwestern Atlantic Ocean and is a parasitic castrator of the slipper limpet Crepidula cachimilla.
