Phylum: Echinodermata

Class: Ophiuroidea

Order: Spatangoida

Family: Spatangidae

Scientific name: Echinocardium cordatum

 

Norwegian: sjømus

(Korsvika - The Trondheim fjord/ 16 meters / 2.07.2004)

Classification: The sea potato is one of seven species of heart urchins - irregular echinoids, registered along the coast of Norway.

Distribution: The most common distribution area stretches from Rogaland in the South, to Nordland in the North. It lives buried, just below the surface (usually 8 to 15 cm), in sandy substrate. It depends on sheltered locations as their shell is very fragile. It is easily crushed if the waves were to dig it up from the sand. It has been reported on depths from 5 to 230 meters.

Characteristics: The color is grey or light brown. The spines are of variable length. The diameter is usually no more then 5 cm, but individuals as large as 9 cm have been reported. In contrast to the two other species of this family, E. flavescens (yellow sea potato) and E. pennatifidum, it has a groove at the anterior end.

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