Holectypoida
The Holectypoida are an order of sea urchins related to the sand dollars. The order consists of just two living genera, but was once more diverse.
| Holectypoida | |
|---|---|
 | |
| Echinoneus cyclostomus | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Superorder: | |
| Order: | Holectypoida Duncan, 1889 |
| Family: | Echinoneidae Agassiz, 1847 |
| Genera | |
|
Echinoneus | |
Description and characteristics
In appearance, the living holectypoids are similar to sand dollars, but with less flattened bodies and an oval outline. They also lack the petal-like patterns found on the bodies of sand dollars.
Taxonomy
According to World Register of Marine Species :
- family Anorthopygidae Wagner & Durham, 1966b †
- family Coenholectypidae Smith & Wright, 1999 †
- family Discoididae Lambert, 1900
- family Holectypidae Lambert, 1900 †
References
- Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 981. ISBN 0-03-056747-5.
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