Aplacophora

Aplacophora
Scientific classification
Kingdom:	Animalia
Subkingdom:	Metazoa
Phylum:	Mollusca
Class:	Aplacophora
Subclasses and families
Subclass Chaetodermomorpha (Caudofoveata) Chaetodermidae Falcidentidae Limifossoridae Metachaetodermatidae Prochaetodermatidae Scutopidae Subclass Neomeniomorpha (Solenogastres) Acanthomeniidae Amphimeniidae Dondersiidae Drepanomeniidae Epimeniidae Gymnomeniidae Hemimeniidae Heteroherpiidae Imeroherpiidae Lepidomeniidae Macellomeniidae Meiomeniidae Neomeniidae Perimeniidae Phyllomeniidae Proneomeniidae Rhipidoherpiidae Rhopalomeniidae Sandalomeniidae Simrothiellidae Strophomeniidae Syngenoherpiidae

Aplacophora is a class of small, deep-water, exclusively benthic, shell-less marine mollusks found in all oceans of the world. The class comprises 28 families and about 320 species. Aplacophorans are mostly very small (no longer than 5 cm), cylindrical and worm-like. Some species however can reach a length of 30 cm.

Habitat

Aplacophorans mainly burrow into the substrate in water regions deeper than 20 m. These species may reach densities up to 4 or 5 specimens per m².

Taxonomy

This class was once classified as sea cucumbers in the echinoderms. In 1987, they were officially recognized as mollusks and given their own class.