| Fiddler crab Temporal range: Early Miocene-recent[1]
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| Red-jointed fiddler crab (Minuca minax) | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Superfamily: | Ocypodoidea |
| Family: | Ocypodidae |
| Groups included | |
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The fiddler crab or calling crab can be one of the hundred species of semiterrestrial marine crabs in the family Ocypodidae.[2] These crabs are well known for their extreme sexual dimorphism, where the male crabs have a major claw significantly larger than their minor claw, whilst females claws are both the same size.[3] The name fiddler crab comes from the appearance of their small and large claw together, looking similar to a fiddle.
A smaller number of ghost crab and mangrove crab species are also found in the family Ocypodidae. This entire group is composed of small crabs, the largest being Afruca tangeri which is slightly over two inches (5 cm) across. Fiddler crabs are found along sea beaches and brackish intertidal mud flats, lagoons, swamps, and various other types of brackish or salt-water wetlands. Whilst fiddler crabs are currently split into two subfamilies of Gelasiminae and Ucinae, there is still phylogenetic and taxonomical debate as to whether the movement from the overall genus of ‘’Uca’’ to these subfamilies and the separate 11 genera[2]
Like all crabs, fiddler crabs shed their shells as they grow. If they have lost legs or claws during their present growth cycle, a new one will be present when they molt. If the major claw is lost, males will regenerate one on the same side after their next molt.[4] Newly molted crabs are very vulnerable because of their soft shells. They are reclusive and hide until the new shell hardens.
In a controlled laboratory setting, fiddler crabs exhibit a constant circadian rhythm that mimics the ebb and flow of the tides: they turn dark during the day and light at night.[5]
- ^ "Uca Leach 1814 (fiddler crab)". PBDB.
- ^ a b Cite error: The named reference
Rosenberg2019was invoked but never defined (see the help page). - ^ Levinton, J. S., Judge, M. L. & Kurdziel, J. P. (1995) Functional differences between the major and minor claws of fiddler crabs (Uca, family Ocypodidae, order Decapoda, Subphylum Crustacea): A result of selection or developmental constraint? Journal of Experimental Marine Biology and Ecology, 193(1-2), 147-160. doi: 10.1016/0022-0981(95)00115-8
- ^ Weis, J. S. (2019). On the Other Hand: The Myth of Fiddler Crab Claw Reversal. BioScience, 69(4), 244-246. doi: 10.1093/biosci/biz011
- ^ Smith, T. & Smith, R. (2012). Elements of Ecology (8th ed.). San Francisco: Pearson Benjamin Cummings. p. 144. https://www.pearson.com/en-us/subject-catalog/p/elements-of-ecology/P200000006836/9780137502165