Starfish, usually Asterias rubens, sometimes get washed ashore in huge numbers on Rhossili beach in Gower, South Wales. Then they disappear again, either washed back out to sea or buried in the sand. Birds peck at them but they do not seem to like to eat them very much. This April, for the first time, I saw ghostly star shapes in the dry sand high on the shore. The long buried stranded starfish were reappearing in skeletal form. You may not have realised that Asteroidean Echinoderms like the Common Starfish had a skeleton. Hidden beneath their often brightly coloured and bumpy skins, bound together by connective tissue, is a lattice network of small calcareous ossicles in the shape of rods, crosses or plates. Spines and tubercles are also part of the skeleton, sometimes separate pieces resting on the deeper dermal ossicles or as extensions of them that project to the outer surface (Barnes 1963).

In these photographs of the dessicated remnants of starfish it is possible to see many small holes in the sand around them. These holes are the places where the scavenging sand hoppers are hiding from the dry hot air and waiting from the tide to return in the cool of the day to recommence cleaning up all the vegetable and animal debris that ends up on the strand-line – like dead starfish.

Reference

Barnes, R. D. (1963) Invertebrate Zoology, R. B. Saunders Company, 526-539.

12 Replies to “Starfish Skeletons”

  1. Thank you, Adrian. You’re right about the fossils! Although, strangely enough, I have never seen fossils of the starfish skeletons. I wonder if they exist? It would be surprising if they didn’t. I must look into it.

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  2. what a fascinating find – thanks for sharing – has whet my appetite to get to the coast next week!

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  3. Thank you, Coleshed. You just never know what you are going to find when you get to the beach. It is always exciting. Have fun when you get there yourself next week.

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