Coscinasterias calamaria

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Coscinasterias calamaria

Scientific classification

Kingdom:	Animalia
Phylum:	Echinodermata
Subphylum:	Eleutherozoa
Class:	Asteroidea
Order:	Forcipulatida
Family:	Asteriidae
Genus:	Coscinasterias
Species:	C. calamaria

Binomial name

Coscinasterias calamaria
(Gray, 1840)

Coscinasterias calamaria, or the eleven-armed sea star, is a sea star of the family Asteriidae, endemic to southern Australia and New Zealand. It is found around low tide levels and below, under rocks and wandering over algae in pools. Armspread is up to 30 cm.

Coscinasterias calamaria is the largest seastar in southern Australia and New Zealand. Although called the eleven-armed sea star there can be any number up to 14, but 11 is the norm. They are often found with arms of varying lengths, regenerating to their original length. It can reproduce itself by fissiparity (self division), being capable of regenerating even one arm into a whole new body, but only if the arm includes part of the central disc. There are rows of spines on the dorsal surface, while rings of pneumatic walking pedicellariae (tubercles) are in parallel rows both underneath and on top of the arms.

There are smell sensors at the tips of the arms, and the animal can navigate precisely to any source of food, often arriving there before others. It then extends its stomach over its prey, to digest it outside its body. It can last for many weeks without food, the body steadily shrinking.

This sea star is normally blue, with shades of brown, orange, red, cream, mauve, green, grey, and white. The bi-coloured spines may be blue at the base and salmon pink at the tips.