Thursday, 28 June 2012

Fossil Sea Urchins

This is the third guest post done by
Sea Urchin and Sand Dollar from our collection
Who, amongst us, has not been excited at discovering the skeleton of a sea urchin. Whether found whilst exploring a rocky pool, or in a seaside souvenir shop, the aesthetic appeal is immediate. We take it home and place it in a prominent place so that its form can continue to be a source of pleasure.
The taxonomic class into which the sea urchin falls is "echinodermata", an invertebrate family of 6,000 living species including starfishes and sea lilies. Some 13,000 extinct species of echinoderms are also known.
The remnants we find of a sea urchin (scientific name: "echinoid") on the beach is the calcareous skeleton with its distinctive five-pointed pattern.
My layman's geological and anthropological interest in sea urchins has been triggered by an article in the June 2012 edition of the magazine "Geoscientist" published by the Geological Society of London, of which eldest son is a Fellow. My granddaughter's recent commencement of studies at Oxford University in archaeology and anthropology has also reinforced my interest. 
The article is entitled "Prehistoric fossil collectors" and is written by Ken McNamara, a senior lecturer at Cambridge University.
The article throws light on the collecting of fossil sea urchins, a practise known to date from as long ago as 400,000 years, when a human ancestor (Homo heldelbergensis) shaped a flint tool in which a fossil sea urchin was incorporated.
courtesy Ken McNamara
The author describes the discovery in the English Chiltern Hills in 1887 of a grave containing the skeletons of a young woman and child. Also in the grave, dating to the Bronze Age some 4,000 years ago, were hundreds of flint balls each carrying the fossilised five-pointed image of a sea urchin. As McNamara puts it "a cornucopia of fossil sea urchins seem to have been buried very carefully with the bodies in their chalky grave".
courtesy Ken McNamara
There are numerous other instances of fossil sea urchins discovered in neolithic barrows (i.e. burial mounds), and in graves set-down as recently as Anglo-Saxon times, which took place over a wide geographical area. The question McNamara attempts to answer is "Why?".
courtesy Ken McNamara
The author speculates that the fossils could have had some great spiritual significance, perhaps in ensuring the passage from this life into the next. Later practises, for example in Celtic cultures, of placing fossil sea urchins on window sills or near to doors, were part of a folklore associated with the bringing of good luck. They are also linked with Norse mythology through the god Thor in which they were called "thunder stones" thrown to earth by Thor. Thor was the peasants' god, who gave them protection; so stones were strategically placed to ward off lightning strikes and to protect the house from evil.
courtesy Ken McNamara
Fossilised Sea Urchins around a window at St Peter's church, Linkenholt, Hampshire
One of the most striking fossil Sea Urchins found was at Heliopolis, Egypt which had hieroglyphs inscribed on it in about 1500 BC. They tell the name of the priest, Tja-nefer, who found it in 'the quarry of Sopdu', a god sometimes known as the 'Morning Star'. McNamara links the five-rayed star on the fossil with the extensive use of the star symbol in Egyptian burial chambers; hence a spiritual connection with the pharaohs and their funeral rites.
He suggests that the myriad modern-day usage of the five-pointed star symbol may have evolved from this usage in ancient times.
There is a lot more fascinating information in Ken McNamara's article, and I would recommend it to those whose interest has been sparked. He is also author of a book "The Star-crossed Stone" published by University of Chicago Press.
Incidentally, fossil Sea Urchins continue to be turned up by the plough in flinty fields, such as on Salisbury Plain, and are still collected to this day! 
Personally, I believe that the aesthetic appeal of both the skeleton and the fossils probably explains, more than anything else the human fascination with these objects. 
First guest blog by H and second.

18 comments:

  1. This is very interesting to me.

    I was born in the Puglia region of Italy. As you might know, in that part of the world we have the cleanest water in the Mediterranean, and our diet is mainly based on seafood, sea urchins being one of our favourites...

    They are incredibly interesting! I have often found dry sea urchin shells on beaches, very pale, and white, kind of chalky.

    In my family, we all love the sea and diving, to catch all kinds of seafood. It's our favourite hobby, in Summer! Sea urchins live amongst bright green, shiny seaweed which look like kale.

    Sea urchins deambulate using a system of pumps, or something like that, they have an orifice, a "mouth" which looks a bit like a beak,just like a starfish, through which they feed.

    They move and "walk" even out of water. We eat sea urchins... raw... their flesh is bright read, soft and very delicate. Inside the shell is also a small amount of seaweed, which maybe the sea urchin had ingested. We eat the flesh and the seaweed inside the shell, by dipping bread in it. There is also an amount of very clean sea water in the sea urchin, which tastes fantastic!

    They are very attractive creatures: the spikes change colour (ranging from black to green and purple)in the sun.

    I find the fossils very interesting. I should imagine that the presence of a star pattern on the fossils would have inspired a kind of link between Earth and sky ( not Heaven, as Prehistoric people had not yet been contaminated by the official church!)as prehistoric people had a very special bond with nature and "things" they could experience through their senses.

    Good article. When I'm in Italy, in three weeks, I'll take a closer look at sea urchins. There is an incredible supply of it in the Adriatic, ready to be caught and "observed!"

    Thank you for an interesting post!

    ANNA

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    1. Anna - I enjoyed your most informative and stimulating comments. I am even more conscious of how little I know about the biology of sea urchins, not even being aware that their flesh is edible and is regarded as something of a delicacy. There is a vast store of knowledge out there, which is great to "dip" into. I like your idea about earth and sky. Many thanks, H.

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  2. An interesting and thoroughly informative guest post. Well done, H!! This is quite timely as many of us are heading to the beaches for summer. We'll certainly appreciate sea urchins and sand dollars even more.
    Cheers from DC,
    Loi

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    1. Hi Loi. So glad you enjoyed this! The replies have really got me thinking - for instance, what led to the name 'sea urchin' becoming common parlance. The name 'Sand dollar' has a more obvious logic to it, as is the feeling of luck when finding one in the sand. Enjoy the summer - H.

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  3. Fascinating H. that ancient people were interested in shells as we are. I collect shells and have a few sand dollars. I do discourage people at the beach from obtaining live sand dollars from the sandy ocean bottom. That causes me distress.

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    1. Hi Olive. Yes, I expect prehistoric man was interested in all sorts of sea shells, as well as those sea urchins that became fossilised. I am reminded of the thousands of medieval pilgrims that, every year, used to make their way across Europe to Santiago de Compostella in Spain. The symbol of this journey is the scallop shell, which they used as a scoop for drinking and then as a dish for food. The ancients would have found many uses for shells I'm sure. Thanks for your comment, especially the point about needless spoilage of marine life - H.

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  4. Strange that these should have been so coveted, H: in the back of my mind the mathematical beauty of them is cannonballing back and forth. A form like that must have posed such questions. And perhaps hinted at the incredible order that masquerades as chaos in this world. Rambling off on a byway, it reminds me of Alan Turing and his quest to find where the tentacles of a spherical organism should be sited- by using mathematical equations. He constructed a theoretical creature who, it was quickly discovered, was real, and swimming around in the ocean. These sea urchins must have shown the ancient civilisations that such order was possible.

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    1. Kate. Thanks for some interesting new observations on mans' fascination with the regular geometric shapes produced by nature. I think this explains the significance that early man attached to these fossils. In the absence of scientific explanations of fossil formation and the evolutionary evidence that fossils carry, the intelligence was such as to see that something extraordinary (magical?) was happening. This also explains their ritualistic treatment. Thanks again. H.

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  5. Dear Rosemary,
    Great and fascinating post.
    I especially like the Sand Dollar.
    Wish you a wonderful weekend.
    Mette

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    1. Hi Mette. What a huge variation in the species between sea urchins and sand dollars, but both carrying that distinctive pattern. One can understand early man's curiosity. Thanks. H.

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  6. A most interesting article! Here in Florida, I've been able to collect sand dollars from a nearby beach, and I've considered arranging them over and around doors, just like the Hampshire window. H, your article makes me wonder whether there's some primal recognition that the urchins and dollars are good luck (aside from being lovely decorations).

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    1. Mark. I often ponder on the distinction between "spirituality" and "superstition", the first being just a more sophisticated expression for mankinds' thoughts on the inexplicable and hence mysterious. For so many fossil sea urchins to have been placed in the bronze age grave I believe suggests there were some more profound thoughts going on in the minds of the perpetrators than simply a superstitious gesture. But we will never know! Clearly, we still have a fascination with that star shape pattern. Thanks. H.
      Incidentally our sand dollar, as you will realise, came from Florida. We do not have them here. However, coming from the same taxonomic class and showing the five point star, decided it would be interesting to include it.

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  7. Very interesting, I like the round photo compositions very much.

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    1. So pleased that you found it interesting - Rosemary made the round photo compositions. Thank you H.

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  8. Fósseis muito interessantes e as fotos estão maravilhosas.
    Beijo
    Graça

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    1. Caro Graça
      Obrigado por seu comentário tipo - Estou contente que você encontrou os fósseis interessante -H.

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  9. what a lovely blog! btw,I am a big fan of sea urchins too (when i dont step on them accidentially;)...indeed Italy is may be the best place (together with south of France) to try them in a dish and they taste so delicious! Personally I am always amazed by the different colourd the sea urchins shells have once noone lives inside anymore; from santorini(Greece) we have brought few years ago some in green and lila (have a look at the pis of them here, if curious: https://picasaweb.google.com/111089509932506348351/GRSantorini#5487057302531350210)

    thanks for this interesting info! btw last week I saw again tons of them underwater while diving in Sardinia:-)

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  10. Hi Jana. Your observation on the varying colours is interesting. Thanks for the reference. The dating of fossilisation of sea urchins to several hundred million years ago gives some idea of the success of the species in finding an enduring niche for itself in marine ecosystems. Thanks for your kind comment. H.

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