Echinocardium australe
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| Echinocardium australe | ||||||||||||||||
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| Echinocardium australe Gray, 1855 |
Echinocardium australe, or the New Zealand heart urchin is a sea urchin of the family Loveniidae, endemic to New Zealand. Length is up to 40 mm.
Echinocardium australe are common but difficult to find animals living buried in soft-sediment habitats. There is a small ventilation slit in the surface of the sediment, or a characteristic track, but often even these small signs are missing. These small sediment-coloured urchins move with almost imperceptible slowness beneath the sediment surface - generally less than 1.5 m per day.
The animal is covered in slender spines of different lengths, which are directed rearwards to streamline the body for burrowing. The tube feet are arranged in two groups, upper and lower. The upper tube feet are long and used to fashion and maintain the vertical ventilation shaft.
Heart urchins ingest organic matter and microscopic plants as they move horizontally in the upper 3 to 4 cm of the sediment. The movement of the animal displaces sediment particles, a process called bioturbation. This movement influences the transport of oxygen and nutrients across the sediment–water interface, and are important to algae which in turn are an important source of food for soft-sediment organisms and indeed the base of the entire marine food web.
[edit] References
- Miller M & Batt G, Reef and Beach Life of New Zealand, William Collins (New Zealand) Ltd, Auckland, New Zealand 1973
- NIWA
