Holothuriidae

Lore & Background

Members of the family Holothuriidae have thick fleshy bodies and several rows of tube feet used for moving and adhering to surfaces. The body is often covered with blunt projections known as papillae. Many members can eject a mass of fine sticky threads called cuvierian tubules to distract predators, or even turn their viscera inside out. For taxonomic determination, the genera Actinopyga and Bohadschia have spicules exclusively shaped like sticks, while Holothuria and Labidodemas never have theirs shaped like tables. Actinopyga is also equipped with anal teeth (modified podia) and never throws out cuvierian tubules, just like Pearsonothuria. Most species are detritivores.

Reader's Guide

Holothuriidae is notable as the second largest family of sea cucumbers, encompassing over 200 species across five accepted genera. Its members are widely distributed in low to middle latitude oceans, often dominating coral reef habitats in the Indo-Pacific. The family is distinguished by several key traits: thick fleshy bodies, rows of tube feet, and papillae-covered surfaces. A remarkable defensive adaptation is the ejection of cuvierian tubules—sticky threads that entangle predators—or the eversion of internal viscera. Taxonomic identification relies on spicule shapes: Actinopyga and Bohadschia have stick-shaped spicules, while Holothuria and Labidodemas lack table-shaped spicules. Actinopyga uniquely possesses anal teeth and, along with Pearsonothuria, never deploys cuvierian tubules. Most species are detritivores, playing a role in nutrient recycling on coral reefs and sandy habitats. The family's diversity and ecological dominance in tropical reefs underscore its significance in marine benthic communities.

Did You Know?

• Members of Holothuriidae can eject sticky cuvierian tubules to distract predators.
• Actinopyga and Pearsonothuria never throw out cuvierian tubules.
• Actinopyga is equipped with anal teeth, which are modified podia.