Atlantic Sand Fiddler Crab
leptuca pugilator
Description 8
The Atlantic sand fiddler, Uca pugilator, is one of approximately 97 species belonging to the family Ocypodidae (Rosenberg 2001). Members of this family are characterized by a thick, squarish body and herding behavior (Ruppert & Fox 1988). Male crabs also bear one greatly enlarged pincer, either right or left, for combat and mating rituals; whereas, the claws of females are roughly equal in size. Fiddler crabs share many common morphological characteristics and behaviors, but identification of species is usually easily achieved through examination of body color and claw structure. Body color of the Atlantic sand fiddler is mostly white to yellowish white, becoming paler during courtship (Crane 1975). Displaying males have a characteristic pink or purple patch on the middle of the carapace, which is often mottled brown in non-displaying males. The major cheliped (appendage bearing the major claw) of the male is yellowish white, often with pale orange at the base of the claw. The minor claw is white, and the eyestalks are buff to grayish white, never green like some similar species. Many tubercles or bumps cover the outer surfaces of the claw. However, the oblique ridge of tubercles common in several fiddler crab species is absent in U. pugilator.
Physical description 9
The Sand fiddler crab is approximately 1.5 inches(38mm) wide and 1.0 inch(25mm) long. All fiddler crabs are similar in shape, having a smooth carapace and a square-shaped body. The eyes are found at the ends of two long and slender, movable eyestalks located in the center of the carapace. Male fiddler crabs are brighter in color, having a purple grey or blue carapace with irregular markings of black or brown. The females have equal-sized claws and generally have a much more subdued coloration on their carapaces. Being that they are crabs they are considered decapods or animals with ten limbs; although both of their claws are not referred to as legs, they are actually chelipeds or claws. Males have a common characteristic of one large pincer. This pincer, which is usually brightly colored, can either be on the right or left side and is at least four times larger than the other. The large cheliped can be as fifty percent as massive as the rest of the male combined. Uca pugilator use the large claw to defend their burrows and attract mates. Fiddler crabs even get their name from the male's large claw.
(He Zhong 2001)
Size 10
The maximum carapace width for U. pugilator is approximately 2.5 cm, but most individuals collected in the field measure up to 1.4 cm and 2.1 cm for carapace length and width, respectively (Crane 1975). The major claw in males is much larger than the body, with a maximum length of 4.1 cm (Gosner 1978) and up to 3.5 cm in most specimens collected in the field (Crane 1975). Little information is reported for the maximum age and average lifespan of U. pugilator. However, the lifespan in a similar species, U. rapax, is only about 1.4 years (Koch et al. 2005).
Look alikes 11
Several other species of fiddlers occupy the estuarine habitats of Florida, including: the saltpan fiddler, U. burgersi; the redjointed fiddler, U. minax; the Atlantic marsh fiddler, U. pugnax; the mudflat fiddler and its subspecies, U. rapax and U. rapax rapax; the longfinger fiddler, U. speciosa; and the Atlantic mangrove fiddler, U. thayeri. The palm, or interior surface, of the major claw in all these species is rougher than that of U. pugilator. The saltpan fiddler is small, with a carapace length of about 1.2 cm (Kaplan 1988). The body is dark mottled brown, with red or pink on the carapace and red on the major claw. Walking legs are usually brown or striped with gray, and the palm of the major claw bears large tubercles. Most populations of U. burgersi are found in mud or muddy sand around mangroves or near the mouths of streams from eastern Florida to South America.The redjointed fiddler is large, with a carapace width reaching 2.3 cm (Kaplan 1988). It is aptly named for the red bands present on the joints of the appendages. The large claw bears many tubercles, which diminish to granules toward the bottom, and the upper finger (movable top part of the closable claw) curves down below the tip of the lower (Kaplan 1988). This species prefers muddy sediments around Spartina marshes, from brackish to nearly freshwater, in Massachusetts to northern Florida and Louisiana.The Atlantic marsh fiddler, U. pugnax, has a carapace approximately 1.2 cm long (Kaplan 1988). The body is usually brown or yellowish with a row of tubercles on the palm of the major claw (Ruppert & Fox 1988). This species is most abundant in muddy areas of salt marshes from Massachusetts to eastern Florida (Kaplan 1988).The carapace of the mudflat fiddler, U. rapax, is about 2.1 cm long and light tan in color (Kaplan 1988). The color of the major claw is similar, with a darker lower palm and finger. The center of the palm is almost smooth, but still bears small granules. This species inhabits mud banks near mangroves and mouths of streams from Florida to South America. Crane (1975) defines the Daytona Beach area on the east coast of Florida as the northern limit for U rapax. The subspecies U. rapax rapax is very similar in appearance (see Crane 1975 for diagnostic characteristics). The longfinger fiddler, U. speciosa, has a small carapace length of about 1.1 cm (Kaplan 1988). Its color is seasonally variable, but usually remains darker than the characteristic brilliant white of the major claw. The palm bears a slightly curved row of large tubercles. These crabs inhabit muddy areas, mostly around mangroves from Florida to Cuba.The Atlantic mangrove fiddler, U. thayeri, has a carapace measuring about 1.9 cm in length (Kaplan 1988). The carapace and major claw are both brown to orange-brown (Crane 1975, Kaplan 1988), and both fingers of the claw are bent down (Ruppert & Fox 1988). This species is found on mud banks of estuaries and streams near mangroves, from Florida to South America. Females often build tall mud chimneys at the entrance to their burrows during breeding season (Crane 1975, Kaplan 1988).Regional Occurrence & Habitat Preference: Populations of U. pugilator inhabit the shores from Massachusetts to Florida (Kaplan 1988), the Gulf of Mexico from Florida to Texas, and the Bahamas (Crane 1975). The Atlantic sand fiddler is found on muddy to sandy soils, but is usually more prominent in sandier areas containing scattered shells and stones (Crane 1975). Individuals also occupy areas around mangroves and in salt marshes, among stands of the cordgrass, Spartina alterniflora (Brodie et al. 2005).
Habitat 12
Fiddler crabs are found in strongly brackish to saltwater salinities all along the eastern seaboard. They live in low marshes, which have sediments that are covered by water on most high tides, characterized primarily by saltmarsh cordgrass. Uca pugilator each live in a hole or burrow that it digs for itself. The burrow can be closed with a mud cap for security. During low tide fiddler crabs abandon its dwelling to search for food, but never strays very far unless it is to court a female or scare away a neighbor.
(Priest 2000)
Aquatic Biomes: coastal
Reproduction 13
Breeding occurs approximately every two weeks for most of the summer. Reproduction occurs in burrows similar to the ones Uca pugilator live in only larger and better-maintained. The two crabs mate and then two weeks later after the incubating of the eggs for the night will return to the surface and release her eggs into the water where they develop. The female when at the water extrudeds all of her fertilized eggs, which can be as many as a quarter million, onto her abdominal flap in one small spongy cluster. The eggs will hatch after several months and will be released into the nearest tidal creek during high tide where again after several months the young fiddler crabs undergo metamorphosis and change into their final form. These new adult crabs return to the land for the rest of their lives.
(Priest 2000)
Link to Access Genomic Data 14
https://www.ncbi.nlm.nih.gov/nuccore/?term=txid6772[Organism:noexp]
Sources and Credits
- (c) Crabby Taxonomist, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/crabby_taxonomist/7212882116/
- (c) Crabby Taxonomist, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/crabby_taxonomist/7212882682/
- (c) Ianaré Sévi, some rights reserved (CC BY-SA), https://upload.wikimedia.org/wikipedia/commons/b/b8/Uca_pugilator_and_hole_crop.jpg
- (c) BJ Stacey, some rights reserved (CC BY-NC), http://www.flickr.com/photos/finaticphotography/8173557983/
- (c) Michael Rosenberg, some rights reserved (CC BY-NC), http://farm3.static.flickr.com/2617/3688548714_729e1406c7.jpg
- (c) Michael Rosenberg, some rights reserved (CC BY-NC), http://farm3.static.flickr.com/2622/3687746575_55edcae005.jpg
- (c) 2010 Barry Rice, some rights reserved (CC BY-NC-SA), http://calphotos.berkeley.edu/cgi/img_query?seq_num=324021&one=T
- (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527688
- Adapted by matbio from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/18678193
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527694
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527691
- Adapted by matbio from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/18678192
- Adapted by matbio from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/18678194
- (c) Emily Rose Sharkey, all rights reserved
