Tunicata is a subphylum of marine chordate animal closely related to the familiar vertebrates in clade Olfactores. The known living members of this clade include tunicates, which superficially resemble poriferans but are quite different in biology. Tunicata is separated into 3 classes; Thaliacea, Larvacea, & the polyphyletic Ascidiacea.
Tunicates, when mature, attach themselves to a rigid surface and siphon for microscopic nutrients much like a sponge.