Sea daisy

The Sea Daisies ( Xyloplax ) are a close until 1986 New Zealand discovered genus of echinoderms. The genus was after their discovery in a separate class, the Concentricycloidea found, but is now counted among the starfish.

It includes only three species, of which Xyloplax turnerae in the Atlantic ( Caribbean Sea, near the island of Andros ), Xyloplax medusiformis in the Pacific off New Zealand and Xyloplax janetae in the northeastern Pacific occurs.

The well-known representatives of this group are only a few millimeters in size and appear to be living in the deep sea at depths up to 2000 meters. X. medusiformis was found in Bohrgängen of piddock in abgesunkenem wood, X. turnerae moved to the lowered test plates, also made of wood, of.

The animals have a calcareous skeleton of overlapping plates have randliche spines and a skeleton ring around the mouth area, which probably represents a group of echinoderms occurring in the Ambulacralsystems. Between the plates, the feet protrude skeleton having no suction discs. Only X. turnerae has a bag stomach, both species probably feed on bacteria that form a film on the wood.

The animals are dioecious and reproduce probably by means of internal fertilization continued. The larval development of at least the Pacific species takes place in the ovary of the females, the animals come so fully developed to the world ( viviparous ).

The systematic classification of the Concentricycloidea is not yet fully understood, currently they are considered mostly as a sister group of sea stars ( Asteroida ). Alternatively, they could also be classified according to the current discussion in the belonging to the starfish Velatida.