Sea urchin
For other uses, see Sea Urchin (disambiguation). Sea urchin Temporal range: Ordovician–Present PreЄ Є O S D C P T J K Pg N Tripneustes ventricosus and Echinometra viridis Scientific classification Kingdom: Animalia Phylum: Echinodermata Subphylum: Echinozoa Class: Echinoidea Leske, 1778 Subclasses Subclass Perischoechinoidea Order Cidaroida (pencil urchins) Subclass Euechinoidea Superorder Atelostomata Order Cassiduloida Order Spatangoida (heart urchins) Superorder Diadematacea Order Diadematoida Order Echinothurioida Order Pedinoida Superorder Echinacea Order Arbacioida Order Echinoida Order Phymosomatoida Order Salenioida Order Temnopleuroida Superorder Gnathostomata Order Clypeasteroida (sand dollars) Order Holectypoida Sea urchins or urchins ( / ˈ ɜːr tʃ ɪ n z / ) are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on ...