| Clypeaster Temporal range: | |
|---|---|
 | |
| Live Clypeaster reticulatus | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Order: | Clypeasteroida |
| Family: | Clypeasteridae |
| Genus: | Clypeaster Lamarck, 1801 |
Clypeaster, common name "cake urchins" or "sea biscuits", is a genus of echinoderms belonging to the family Clypeasteridae.
The genus name Clypeaster is derived from the Latin “clypeus” (meaning round shield) and “aster” (meaning star), with reference to the shape of these organisms.
The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.
Cidaris is a genus of pencil sea urchins.
Astropecten is a genus of sea stars of the family Astropectinidae.
Coelopleurus is an extant genus of echinoids with fossil records dating back to the Eocene, with remains found in Europe and North America.
Spatangus is a genus of heart urchins in the Spatangidae family. The genus is synonymous with the previously recognised genera Prospatangus Lambert, 1902 and Spatagus. There are nine recognised species. The type species is Spatangus purpureus Müller, 1776 by subsequent designation.
The Oreasteridae are a family of sea stars in the class Asteroidea.
Anthenea is a genus of sea stars in the family Oreasteridae. Members of this genus are most commonly observed off the coasts of Australia and southeast Asia.
Luidia is a genus of starfish in the family Luidiidae in which it is the only genus. Species of the family have a cosmopolitan distribution.
Schizaster is a genus of heart urchins belonging to the family Schizasteridae. The type species of the genus is Schizaster studeri.
Histocidaris is a genus of sea urchins in the family Histocidaridae. Some species are known from the fossil record.
Caenopedina is a genus of sea urchins of the family Pedinidae.
Stylocidaris is a genus of echinoderms belonging to the family Cidaridae.
Brissopsis is a genus of echinoderms belonging to the family Brissidae.
Ophiura is a genus of echinoderms belonging to the family Ophiuridae.
Echinocyamus is a genus of echinoderms belonging to the family Fibulariidae.
Stereocidaris is a genus of echinoderm belonging to the family Cidaridae.
Metalia is a genus of echinoderms belonging to the family Brissidae.
Echinolampas is a genus of echinoderms belonging to the family Echinolampadidae.
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