Full reference: J. W. Durham and K. E. Caster. 1963. Helicoplacoidea: a new class of echinoderms. Science 140(3568):820-822
Parent taxon: Echinodermata according to J. W. Durham and K. E. Caster 1963
See also Sepkoski 2002
Sister taxa: Asterozoa, Blastozoa, Camptostromoidea, Cincta, Crinoidea, Ctenocystoidea, Ctenoimbricata, Cyclocystoidea, Discoidea, Echinoconus, Echinozoa, Edrioasteroidea, Eleutherozoa, Helicocystitidae, Holothuroidea, Homoiostelea, Homostelea, Iheringiana, Mesocrinus, Paracrinozoa, Pediculacaudinidae, Pelmatozoa, Peripneustes, Scoteinocystis, Scutellidae, Scutellinidae, Semperitidae, Stylophora, Tubocaudinidae
Subtaxa: Helicoplacida Helicoplacidae Polyplacida Westgardellidae
Ecology: stationary low-level epifaunal suspension feeder