cheliped

A cheliped is the pincer-bearing first pair of thoracic legs (pereiopods) in many decapod crustaceans, including crabs, lobsters, crayfish, and shrimp. The limb bears a specialized grasping organ called a chela, or claw, at its distal end. The two fingers form a pincer: a fixed finger on one side and a movable finger (the dactyl) on the other that closes against it when the muscles contract. The cheliped is usually the strongest and most conspicuous leg, often larger than the other pereiopods.

Anatomy and variation: The cheliped shows marked variation among species; in many, the first pair is enlarged for combat, prey capture, and display. In some species, notably fiddler crabs, one cheliped is dramatically enlarged in males and used mostly for signaling a rival; in others, such as lobsters and crayfish, the chelipeds are heavy and function in grasping and tearing prey. In all decapods, chelipeds can be shed and regenerated during molts, though regrowth can take multiple molts and may reduce performance temporarily. The cheliped's size and strength influence feeding ecology, defense strategies, and social interactions within populations.