Euechinoidea

The subclass Euechinoidea includes almost all living species of sea urchin, with fossil forms going back as far as the Triassic.

Taxonomy
List of orders according to World Register of Marine Species:
 * Infraclass Acroechinoidea
 * Order Aspidodiadematoida
 * Order Diadematoida
 * Order Micropygoida
 * Order Pedinoida
 * Infraclass Carinacea
 * Superorder Calycina
 * Order Phymosomatoida†
 * Order Salenioida
 * Superorder Echinacea
 * Order Arbacioida
 * Order Camarodonta
 * Order Stomopneustoida
 * Order Echinothurioida
 * Infraclass Irregularia
 * Superorder Atelostomata
 * Order Holasteroida
 * Order Spatangoida
 * Order Echinoneoida
 * Order Holectypoida†
 * Superorder Neognathostomata
 * Order Cassiduloida
 * Order Clypeasteroida
 * Order Echinolampadoida
 * Order Nucleolitidae†