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Taxonomy and Biogeography of the Fiddler Crabs (Ocypodidae: Genus Uca) of the Atlantic and Gulf Coasts of Eastern North America
Zoological Journal of the Linnean Society (2008)
  • F. H. Barnwell
  • Carl L. Thurman, University of Northern Iowa
Fifteen species of fiddler crabs are reported for eastern North America between Massachusetts and Quintana Roo, Mexico. Thirteen occur in the United States and 11 in Mexico, with eight in common to the two countries. Of 13 species in the Gulf of Mexico, five are endemic and a sixth is restricted largely to the peninsulas of Florida and Yucatan. The status of U. rapax in the northern Gulf remains to be resolved. Range limits of most species approximate one or the other of two sets of intersecting thermal and geological boundaries that subdivide the Gulf of Mexico along north-south and east-west axes. Species belonging to subgenus Minuca tend to replace one another at the thermally-controlled Carolinian-Caribbean marine biotic boundary across the Florida peninsula and northern Gulf. However, only U. minax of all the North American fiddler crabs exhibits the classical disjunct Carolinian distribution, and this appears basically to reflect the discontinuous distribution of temperate salt marshes that are the habitat of the species. Distributions of species belonging to subgenus Celuca adhere for the most part to the subdivision of the Gulf into western terrigenous and eastern carbonate sedimentary provinces. The northern transition occurs in the vicinity of Apalachee Bay and the southern at Laguna de Terminos. A third distributional pattern is shown by U. subcylindrica, a specialized endemic species of the hypersaline Laguna Madre system of the western Gulf. The level of endemism in the fiddler crabs is relatively high in comparison with that of other marine groups within the Gulf of Mexico. This may be a consequence of the adaptations of fiddler crabs as specialized deposit feeders to regional differences in climatic and edaphic characteristics of a marginally marine upper shore habitat. The distributional patterns of the endemics could prove useful in reconstructing palaeoecological events of evolutionary significance within the Gulf of Mexico.
  • Uca,
  • fiddler crabs,
  • taxonomy,
  • ecology,
  • biogeography,
  • Gulf of Mexico,
  • North America
Publication Date
May 15, 2008
Citation Information
F. H. Barnwell and Carl L. Thurman. "Taxonomy and Biogeography of the Fiddler Crabs (Ocypodidae: Genus Uca) of the Atlantic and Gulf Coasts of Eastern North America" Zoological Journal of the Linnean Society Vol. 81 Iss. 1 (2008) p. 23 - 87
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