Chiridotidae

Background

Chiridotidae are found worldwide and typically inhabit benthic ecosystems, where they feed on detritus. They undergo direct development, with the gastrula developing directly into the doliolaria larvae, bypassing the Auricularia stage. This allows internal brooding of young within the coelom or ovaries.

Chiridotidae are mostly nocturnal and dependent on light for regulating body processes. They are known for burrowing into the seafloor. The body wall is thin and mostly transparent.

An amino acid peptide called Stichopin affects stiffness in connective tissues and muscle contraction. The calcareous ring is composed of small plates bound by connective tissues, providing structural support to the pharynx, tentacles, water vascular system, and radial nerve ring. Ciliary urns are coelomic organs that gather and excrete waste, aiding immunity. Ossicles are generally wheel-shaped with six spokes, and include rods, hooks, denticles, and miliary granules.

Hooks are found only in three living genera: Taeniogyrus, Scoliorhapis, and Trochodota. Movement relies on peristaltic movements and anchors, as the family lacks tube feet. Tentacles around the mouth are forked and help guide food into the mouth.