Holectypoida
| Holectypoida Temporal range: | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Subclass: | Euechinoidea |
| Infraclass: | Irregularia |
| Order: | Holectypoida Duncan, 1889 |
| Families[1] | |
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.
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.[2]
Taxonomy
According to World Register of Marine Species:
- †Anorthopygidae Wagner & Durham, 1966
- †Coenholectypidae Smith & Wright, 1999
- Discoididae Lambert, 1900
- †Holectypidae Lambert, 1900
References
- ^ "Holectypoida". WoRMS. World Register of Marine Species. Retrieved 29 July 2024.
- ^ Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 981. ISBN 0-03-056747-5.