Velatida
| Velatida | |
|---|---|
 | |
| Pteraster capensis | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Subphylum: | Eleutherozoa |
| Class: | Asteroidea |
| Order: | Velatida Perrier, 1884 |
| Families | |
|
| |
The Velatida are an order of sea stars containing about 200 species in five families. These asteroids normally have thick bodies with large discs.[1]
Description and characteristics
This order contains mostly deep or cold seas sea stars, often with a wide distribution (sometimes global). They have a pentagonal or star shape, with between 5 and 15 arms. Their skeleton is weakly developed, which confers them a good flexibility, and the numerous papillae which cover their aborale face allow them to breathe in poorly oxygenated waters. Their pedicellariae are often provided with spines. The smallest are Caymanostellidae (between 0,5 and 3 cm) and the biggest Pterasteridae (up to 30 cm).[2]
Taxonomy
New molecular evidence now suggests a relationship between some velatid and valvatid families.
List of families according to World Register of Marine Species:[3]
- Caymanostellidae Belyaev, 1974
- Korethrasteridae Danielssen & Koren, 1884
- Myxasteridae Perrier, 1885
- Pterasteridae Perrier, 1875
Myxaster sp., a Myxasteridae
Hymenaster sp., a Pterasteridae
References
- ↑ "Asterozoa: Fossil groups: SciComms 05-06: Earth Sciences". Palaeo.gly.bris.ac.uk. 2005-11-22. Retrieved 2010-07-30.
- ↑ Mah, Christopher L. "Velatida". www.accessscience.com.
- ↑ "The World Asteroidea Database - Velatida". Marinespecies.org. Retrieved 2010-07-30.