Fiddler crabs are small, semi-terrestrial crabs are characterized by extreme cheliped asymmetry in males. They are most closely related to the Ocypode (ghost crabs). There are currently 107 recognized extant species.
| Kingdom | Animalia |
| Phylum | Arthropoda |
| Class | Crustacea |
| Sub-class | Malocostraca |
| Order | Decapoda |
| Infraorder | Brachyura |
| Superfamily | Ocypodoidea |
| Family | Ocypodidae |
| Genera | Afruca, Austruca, Cranuca, Gelasimus, Leptuca, Minuca, Paraleptuca, Petruca, Tubuca, Uca, Xeruca |
The common English name “Fiddler Crab” comes from the feeding of the males, where the movement of the small claw from the ground to its mouth resembles the motion of a someone moving a bow across a fiddle (the large claw).