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Concentricycloidea
Sea daisies (order Peripoda) make up a small group belonging to the echinoderms, with two species described in a single genus.
Characteristics
These species have disk-shaped flattened body and are less than 1 cm in diameter. They have a water-vascular system and are dotted with tube feet around the edge of the disk. They do not have arms, but five ambulacral areas. They do not have mouthparts either, so they seem to get nutrition through the membrane surrounding their body.
Sea daisies typically have two circummoral canals and a single peripheral ring of podia. It is not clear yet if they belong to the asteroid clade or not.
Spotting
More than a 100 specimens belonging to this order have been recorded at two main sites: off the waters of New Zealand in deep-sea environment, and in the Bahamas. They are always found in deep waters, living upon decaying wood.
Classification
They were discovered in 1986 and their position within the echinoderms has been contentious, being placed at first in a new class, Concentricycloidea. As of 2005, they are placed with starfish in the class Asteroidea.
Family Xyloplacidae
- Genus Xyloplax
- Xyloplax medusiformis
- Xyloplax turneae
Referenced By
Echinoderm | Echinodermata
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