Pinnixa chaetopterana | |
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Species: | P. chaetopterana |
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Pinnixa chaetopterana Stimpson, 1860 | |
Pinnixa chaetopterana, the tube pea crab, is a small decapod crustacean that lives harmlessly within the tube of the polychaete worm, Chaetopterus variopedatus .
P. chaetopterana is a tiny, soft-bodied crab. The bodies of all species of Pinnixa are much wider than they are long. The adults are difficult to distinguish from each other and all live in the tubes or burrows of other invertebrates. [1]
The larvae are quite dissimilar to the adults. They spends some time drifting in the zooplankton and there are five zoeal stages. The carapace is caltrop-shaped and has dorsal, rostral and lateral spines. The antennae are limited to a spinous process and a single seta. The length of the dorsal spine is less than 1.5 times the length of the rostral spine. The second and third abdominal somites have dorso-lateral knobs and the fifth somite has lateral knobs that project wing-like over the telson which has a median notch. [2] [3]
This crab is found on the western side of the Atlantic Ocean, including Brazil, the Gulf of Mexico, Florida, North Carolina and Massachusetts. [2] It lives at depths of up to sixty metres. [2]
Although Chaetopterus variopedatus is of cosmopolitan distribution, P. chaetopterana and another pea crab, Polyonyx gibbesi , are only found associated with it along the eastern seaboard of America from Massachusetts to Uruguay. The latter is an obligate commensal of the tube worm whereas P. chaetopterana is a facultative one. The latter is occasionally free living and also sometimes associates with other hosts such as another polycheate worm, Amphitrite ornata . The two species of crab are intolerant of each other and if placed together in a dish will fight and tear off each other's limbs. In the tube of C. variopedatus, a pair of crabs will take up a position posterior to the worm and if the worm turns round, they move so as to remain behind it. [4] It is likely that the crabs gain protection from predators within the tubes and gather food in the form of plankton from the water pumped past them by the host worm. [5] The crabs may bite holes in the tube to increase the size of the aperture and go in and out at will. [6]
The ribbon worm, Carcinemertes pinnotheridophila , is a parasite found in the branchial chambers of this pea crab, and the worm's eggs can sometimes be seen attached to the hairs on the second abdominal appendage of the female crab alongside her own eggs. [7]
Ovalipes ocellatus, known as the lady crab, is a species of crab from eastern North America. Other names for it include the leopard crab or Atlantic leopard crab due to the leopard-like rosette patterns on its shell, the calico crab, or ocellated crab. It has a shell 3 in (7.6 cm) long and only slightly wider, which is covered in clusters of purple spots. It occurs from Canada to Georgia, and lives mainly on molluscs, such as the Atlantic surf clam.
Stenorhynchus seticornis, the yellowline arrow crab or simply arrow crab, is a species of marine crab.
Enopla is one of the classes of the worm phylum Nemertea, characterized by the presence of a peculiar armature of spines or plates in the proboscis.
Lophius americanus is a goosefish in the family Lophiidae, also called all-mouth, American anglerfish, bellows-fish, devil-fish, headfish, molligut, satchel-mouth, or wide-gape. It is native to the eastern coast of North America.
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.
Eupolymnia crassicornis is a tropical species of annelid, commonly known as a spaghetti worm. These worms are found mainly near the Florida Keys and Puerto Rico. They can be found on the sea bottom near rocks and sand. They live buried in the sand where they create a tube-like structure. They extend their thin white tentacles out of the top of the tube in which they dwell.
Chaetopterus or the parchment worm or parchment tube worm is a genus of marine polychaete worm that lives in a tube it constructs in sediments or attaches to a rocky or coral reef substrate. The common name arises from the parchment-like appearance of the tubes that house these worms. Parchment tube worms are filter feeders and spend their adult lives in their tubes, unless the tube is damaged or destroyed. They are planktonic in their juvenile forms, as is typical for polychaete annelids. Species include the recently discovered deep water Chaetopterus pugaporcinus and the well-studied Chaetopterus variopedatus.
Percnon gibbesi is a species of crab. It is one of at least two species commonly called "Sally Lightfoot", and is also referred to as the nimble spray crab or urchin crab. It has been described as "the most invasive decapod species to enter the Mediterranean".
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The larvae of crustaceans often bear little resemblance to the adult, and there are still cases where it is not known what larvae will grow into what adults. This is especially true of crustaceans which live as benthic adults, more-so than where the larvae are planktonic, and thereby easily caught.
Hepatus epheliticus, known by various names, including the calico crab and Dolly Varden crab, is a species of crab. It lives in shallow water in the western Atlantic Ocean from the Chesapeake Bay to the Dominican Republic. It has a 3-inch (76 mm)–wide carapace adorned with large red spots with darker outlines.
Haemulon flavolineatum, the French grunt, banana grunt, gold laced grunt, open-mouthed grunt, redmouth grunt, or yellow grunt, is a species of marine ray-finned fish, a grunt belonging to the family Haemulidae. It is native to the western Atlantic Ocean.
Tumidotheres maculatus is a species of crab that lives commensally or parasitically in the mantle cavity of molluscs. It is found along much of the western Atlantic Ocean and was first described by Thomas Say in 1818.
Chaetopterus variopedatus is a species of parchment worm, a marine polychaete in the family Chaetopteridae. It is found worldwide. However, recent discoveries from molecular phylogeny analysis show that Chaetopterus variopedatus sensu Hartman (1959) is not a single species.
Amphitrite ornata or ornate worm, is a species of marine polychaete worm in the family Terebellidae.
Libinia dubia, the longnose spider crab, is a species of crab in the family Epialtidae. It is found in shallow waters on the eastern coast of North America.
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.
Trachurus lathami is a species of fish in the family Carangidae and the genus Trachurus, the jack mackerels. Common names include rough scad and horse mackerel in English, as well as chinchard frappeur (French), chicharro garretón (Spanish), jurel, and carapau, garaçuma, surel, and xixarro. It is native to parts of the western Atlantic Ocean, including seas off the eastern coasts of North and South America and the Gulf of Mexico.
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.
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.