Shining symmetry

Sea urchins are beautiful and fascinating, whether alive or dead. Some would say delicious, too, but I haven’t sampled them, despite living and working in Japan and Hong Kong for a bit and backpacking solo all over South-East Asia for three months.

Sunshine through sea urchin

Hundreds of little hydraulic-driven feet move them about, and are protected by their spines.

Sea urchin (Tripneustes gratilla?) at Flat Rock, Ballina

Pink sea urchin, photo by Mo Dickson

You can see the little tube feet between the spines in the pink sea urchin (Holopneustes pycnotilus, sometimes called the thickened sea urchin) above.  According to Davey’s A Photographic Guide to Seashore Life, it is confined to NSW between the Richmond River and Ulladulla (south of Sydney). This one is from Flat Rock, just north of where the Richmond River comes out into the sea at Ballina.

The photo below (Heliocidaris erythrogramma?) shows, in the centre, the ‘Aristotle’s lantern‘ – the hard central mouthparts – which the animal uses to scrape off algae for eating.

Worse for wear, but still alive and kicking, photo by Mo Dickson

The red-spined sea urchin (Holopneustes porosissimus, below) is ‘almost always found wrapped up in algal fronds during feeding’ (according to Sea Stars of Australasia and their Relatives, by Coleman).


Red-spined sea urchin

Sea shell, sea shell, sing a song for me
Tell me about the ocean, tell me about the sea.

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3 Responses to Shining symmetry

  1. brian says:

    Good job with the photo’s & explanations… I love
    these little creatures. Looks like it was a fun discovery.

  2. Cath Clark says:

    SPINEY. So this is where you put the glowing urchin photo. I thought by the title it would have been spiders.

  3. Lilly Green says:

    The pink sea urchin is my favorite picture. Sea urchins are quite beautiful creatures.

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