Fiddler-crab
Guides
Leptuca crenulata
Mexican fiddler crab
The Mexican fiddler crab is a small intertidal crab formerly classified in the genus Uca but transferred to Leptuca in 2016. Females exhibit active mate searching behavior, which is notable as this represents a reversal of typical sex roles in fiddler crabs where males usually search for mates. The species inhabits intertidal mudflats and shows the characteristic sexual dimorphism of fiddler crabs, with males possessing one greatly enlarged claw used for signaling and combat.
Leptuca thayeri
Atlantic mangrove fiddler crab, mangrove fiddler
Leptuca thayeri is a true crab in the family Ocypodidae, commonly known as the Atlantic mangrove fiddler crab. Formerly classified in the genus Uca, it was moved to Leptuca in 2016 based on phylogenetic revisions. The species inhabits mangrove sediments along the Western Atlantic coast, where it constructs burrows and influences sediment structure through bioturbation. Males possess one greatly enlarged claw used for display and combat. The species exhibits a resource-free mating system, an unusual reproductive strategy among fiddler crabs.
Minuca longisignalis
longwave gulf fiddler, Gulf Marsh Fiddler Crab
Minuca longisignalis, formerly Uca longisignalis, is a fiddler crab endemic to Gulf of Mexico salt marshes. It exhibits striking reproductive seasonality characteristic of warm-temperate lineages, with ovigerous females appearing no earlier than April and peak ovigery in June. The species constructs burrows in vegetated marsh areas, with burrow density and depth varying by elevation and distance from shoreline. It co-occurs with congeners such as Uca spinicarpa, though shows substrate preferences for different clay compositions.
Uca
Narrow-fronted Fiddler Crabs, fiddler crabs, calling crabs
Uca is a genus of semi-terrestrial marine crabs comprising approximately 100 species, commonly known as fiddler crabs or calling crabs. Males are distinguished by one greatly enlarged claw used for visual displays and combat. These small crabs inhabit intertidal zones worldwide, where they construct burrows and feed on organic material in surface sediments. Their burrowing activity contributes significantly to sediment turnover and nutrient cycling in coastal ecosystems.
Uca minax
red-jointed fiddler crab, brackish-water fiddler crab
Minuca minax is a fiddler crab species distinguished by its tolerance for low-salinity and freshwater habitats, extending farther inland than most congeners. Males possess one greatly enlarged claw with red joints, the source of its common name. Formerly classified in genus Uca, it was transferred to Minuca in 2016. The species is abundant in salt marshes and tidal streams along the U.S. Atlantic and Gulf coasts, with documented populations occurring more than 50 km from the sea.
Uca pugilator
sand fiddler crab, Atlantic sand fiddler crab, Calico fiddler
Leptuca pugilator is a temperate fiddler crab species found on the Atlantic coast of North America, from Massachusetts to the Gulf of Mexico. It inhabits intertidal mudflats and sandy estuarine shores, where it constructs burrows and occurs in extremely high densities. Males possess one dramatically enlarged claw used for territorial defense and combat with rival males. The species was transferred from genus Uca to Leptuca in 2016 based on phylogenetic evidence.
Uca pugnax
Atlantic marsh fiddler crab, mud fiddler crab, Atlantic mud fiddler crab, marsh fiddler crab
Minuca pugnax is a small intertidal crab native to Atlantic coast salt marshes of North America. Males possess one dramatically enlarged yellow claw used for signaling and combat, while females have two small claws. The species exhibits sexual dimorphism in body size and coloration. It constructs burrows in muddy substrates and has been observed in both low-marsh and, more recently, high-marsh habitats. Larval development includes five zoeal stages and one megalopal stage before settlement.