Hidden treasures

7 Dwarf cushion-star

Perusing a rock pool in the intertidal zone will yield a wide variety of sea life, but if you look really closely you can find some hidden treasures camouflaged amongst the algae and rocks. Dwarf cushion-stars Parvulastra exigua are small starfish roughly 2 cm in size, which are found along the Indian Ocean coastline and have beautiful patterns in orange, brown, green and white. These starfish are flattened, and have under-developed arms appearing more like a pentagon than a well-defined star. The dorsal/upper surface of the animal is made up of a number of tile-like plates which each have knobbly spines. Dwarf cushion-stars feed by extruding their stomachs through their mouths and digesting microscopic algae off the rocks they are attached to.

Written by: Minke Witteveen

For more reading:
• Branch, G.M., Griffiths, C.L., Branch, M.L. and Beckley, L.E. 2010. Two Oceans: A guide to the marine life of southern Africa. Pp. 224. Random House Struik Publishers, Cape Town.

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