Cidaroida
| Cidaroida Temporal range: | |
|---|---|
| Cidaris cidaris | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Subclass: | Perischoechinoidea |
| Order: | Cidaroida Claus, 1880 |
| Families | |
Cidaroida, also known as pencil urchins, is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic.