Pedicellaria

: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea).

[1][2] Each pedicellaria is an effector organ with its own set of muscles, neuropils, and sensory receptors and is therefore capable of reflex responses to the environment.

Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organisms, and other debris in conjunction with the ciliated epidermis present in all echinoderms.

Four main forms of pedicellariae are found in sea urchins : tridactylous, ophicephalous, triphyllous and globiferous.

This is particularly the case in the family Toxopneustidae, some species such as Tripneustes gratilla and especially Toxopneustes pileolus being extremely venomous.