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 Temporal range:
| |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Subclass: | Euechinoidea |
| Infraclass: | Irregularia |
| Order: | Holectypoida Duncan, 1889 |
| Families[1] | |
Description and characteristics
editIn 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
editAccording to World Register of Marine Species:
- †Anorthopygidae Wagner & Durham, 1966
- †Coenholectypidae Smith & Wright, 1999
- Discoididae Lambert, 1900
- †Holectypidae Lambert, 1900
References
edit- ^ "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.
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