spinulosida

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Mosaic Sea-star - Plectaster decanus 

The Mosaic Sea-star, scientifically named Plectaster decanus (Spinulosida - Echinasteridae) is one of the most beautiful sea stars that you can find in the cooler waters of southern Australia.

The most distinctive feature of this striking sea star is a series of ridges that form a mosaic pattern across the top of the surface. Its color can vary greatly from red, pink, orange, yellow and purple. It has a maximum arm width of approximately 25 cm.

The incredibly bright colors of this sea star may be a warning that it contains toxic chemicals. If carried with bare hands it causes numbness. The mosaic sea star feeds mostly on sponges, and these may be the source of its toxins. 

Reference: [1] - [2]

Photo credits: [Top: ©John Turnbull | Locality: Bare Island, north side of Botany Bay, Sydney, Australia, 2013] - [Middle: ©Richard Ling | Locality: Inscription Pt, Botany Bay, New South Wales, Australia, 2007] - [Bottom: ©Richard Ling | Locality: Home Bommie, Ulladulla, New South Wales, Australia, 2010]

Echinaster sepositus

Sometimes known as the “Red Starfish”, Echinaster sepositus is a species of Echinasterid sea star which occurs along the coasts of western Europe, mainly France. Echinaster sepositus is typically seen on rocky, muddy, or sandy bottoms, and commonly among eel-grass where it will feed on sessile invertebrates. 

Classification

Animalia-Echinodermata-Asteroidea-Spinulosida-Echinasteridae-Echinaster-E. sepositus

Image: Tato Grasso