A phylum of marine invertebrates which includes starfishes, sea urchins, brittlestars, crinoids, and sea cucumbers. They have fivefold radial symmetry, a calcareous skeleton, and tube feet operated by fluid pressure.
- ‘The superphylum Deuterostomia contains the diverse phyla Chordata and Echinodermata and the minor phyla Hemichordata and Urochordata.’
- ‘Sea cucumbers, invertebrate animals of the phylum Echinodermata, might hold out some hope for the afflicted.’
- ‘Crinoids are a class of the phylum Echinodermata, which includes living starfishes, sand dollars and sea urchins, as well as approximately six hundred living species of crinoids.’
- ‘Some zoologists would put the Urochordata closer to the Echinodermata, instead of within the Chordata proper.’
- ‘A traditional hypothesis of the Echinodermata using only extant taxonomic groups places the Asteroidea and Ophiuroidea as sister groups based on the shared derived characteristic of a five-rayed body plan.’
Modern Latin (plural), from Greek ekhinos ‘hedgehog, sea urchin’ + derma ‘skin’.