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:
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| Echinoneus cyclostomus | |
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| Kingdom: | |
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| Order: | Holectypoida Duncan, 1889
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| Family: | Echinoneidae Agassiz, 1847
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| Genera | |
Description and characteristics edit
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 edit
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 edit
- Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 981. ISBN 0-03-056747-5.
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