Common Sea Urchin Heliocidaris erythrogramma
Its oval-shaped form is flattened above and below so that the test is only half as high as wide. The circular primary spines are long (25 mm) and taper gradually to a point. Secondary spines are not so tapered and have more blunt tips.
The test is covered with coarse tubercles. Test diameter to 90 mm.
The test may be light purple, green or creamy-white. The primary spines are purple to dark olive-green. Secondary spines are also purple or dark green. The tube feet are pale pink.
The Common Sea Urchin ranges from Port Stephens, New South Wales around southern shores to Shark Bay and the Abrolhos in Western Australia.
Occurs under stones and overhanging ledges in pools and gutters at low tide level and below.
This is the most common sea urchin in southern Australia. This sea urchin can carve out hemispherical hollows in the rock at the lowest tide levels and below on rocky shores and in rock pools on the exposed edge of rock platforms facing the sea.
How do you think a sea urchin can carve out a home hollow in rock ?
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