fiddler crab

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fiddler crab,

common name for small, amphibious crabscrab,
crustacean with an enlarged cephalothorax covered by a broad, flat shell called the carapace. Extending from the cephalothorax are the various appendages: five pairs of legs, the first pair bearing claws (or pincers), are attached at the sides; two eyes on short, movable
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 belonging to the genus Uca. They are characterized by a rectangular carapace (shell) and a narrow abdomen, which is flexed under the body. They are called fiddler crabs because the males have one enormous claw, held in front of the body like a fiddle. This claw often contrasts in color with the rest of the body, and is used by the male at certain times of the year to attract females in a complicated courtship display procedure, characteristically different in each species of Uca. The claw also functions to warn off intruders and to establish territories. The female Uca has two small claws on the first appendages. Some species of fiddler crabs live on sandy beaches that are somewhat protected from extreme wave action. Others live in muddy marshes and estuaries. The Uca species living on sandy beaches, such as the common Atlantic fiddler, U. pugilator, make burrows about 1 ft (30 cm) deep, just below the high tide line. The sand is carried to the surface by specialized legs of the crab, and pushed away from the entrance. Fiddler crabs are poor swimmers and rarely enter the water during their adult lives. During the spring and summer, the fiddlers remain in their burrows only during high tide periods. The entrances of the burrows are covered with sand, and the burrows contain a bubble of air, which the crabs use for respiration. When the tide ebbs, the fiddlers emerge and scurry about, collecting food in the drift lines left by the ebbing water. Both claws of the female and the smaller claw of the male are used to scoop up sand and pass the grains to the mouthparts. Certain specialized appendages (the first and second maxillipeds) have spoon-shaped setae, used to scour organic matter from the sand grains and pass it to the mouth. The sand grains are then rejected in the form of small sand balls. After mating, the female fiddler crab carries the fertilized eggs under her flexed abdomen. Certain cyclic changes occur in Uca (as well as in some other crustaceans), such as changes in pigmentation. During the day the crabs are dark; at night they are pale. Fiddler crabs are classified in the phylum ArthropodaArthropoda
[Gr.,=jointed feet], largest and most diverse animal phylum. The arthropods include crustaceans, insects, centipedes, millipedes, spiders, scorpions, and the extinct trilobites.
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, subphylum Crustacea, order Decapoda.
References in periodicals archive ?
The distribution of fiddler crabs (Uca) along the coast of Brazil: implications for biogeography of the western Atlantic Ocean.
Reproductive aspects of a tropical population of the fiddler crab Uca annulipes (H.
Around 97 species of fiddler crabs are currently known worldwide (Beinlich & Von Hagen, 2006; Landstofer & Schubart, 2009; Shih et al., 2009, 2010; Naderloo et al., 2010).
"It appears that fiddler crabs have evolved inbuilt sunglasses, in the same way as we use polarising sunglasses to reduce glare," Professor Marshall said.
Also, encysting metacercariae of the parasite are readily available in the green glands of Uca pugnax fiddler crabs from the marshes of southeast Georgia.
"A BUS RIDE AWAY IS TAI O, A TRANQUIL FISHING VILLAGE WITH MANGROVES, FIDDLER CRABS AND STILT HOUSES STUDDED WITH "BILLIONS OF BLISTERING BARNACLES" THAT CAPTAIN HADDOCK WOULD BE PROUD OF."
Dr Zachary Darnell and Assistant Professor Pablo Munguia tested a bunch of Gulf coast fiddler crabs (Uca Panacea) - both those who still had their major claws and those who had lost theirs.
Ecologists knew that male fiddler crabs sometimes take on an attacker who is trying to invade a neighbor's territory.
In addition, fiddler crabs normally play a crucial role in tilling the salt marsh, which helps provide oxygen to the roots of salt marsh grasses.
Egrets fish on the banks and fiddler crabs scurry to their burrows as you glide along the shoreline, listening to the sounds of shorebirds and the "drip-drip-drip" of water off your paddle.
Even fiddler crabs, I gather, display 'an elevated level of aggressive interactions' during the week of the full moon.