Valvatida
| Valvatida | |
|---|---|
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| Two Valvatida : a Solaster dawsoni attacking a Hippasteria spinosa | |
| Scientific classification | |
| Kingdom: | Animalia |
| Subkingdom: | Eumetazoa |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: |
Valvatida Perrier, 1884 |
| Families | |
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The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families.
The order encompasses both tiny species, which are only a few millimetres in diameter, like those in the genus Asterina, and species which can reach up to 75 cm, such as species in the genus Thromidia. Almost all species in this order have five arms with tube feet. This order is primarily identified by the presence of conspicuous marginal ossicles, which characterize most of the species. Most members of this order have five arms and two rows of tube feet with suckers. Some species have paxillae and in some, the main pedicellariae are clamp-like and recessed into the skeletal plates. This group includes the cushion star, and the leather star.
According to the World Register of Marine Species, the following families are included in Valvatida:
Crown-of-thorns starfish (Acanthaster planci)
Cushion star (Culcita novaeguineae)
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Wikipedia