Thorny outside, soft inside!

Dear friends of Medi sea, it is my honour today to introduce to you the Mediterranean's true oyster, Spondylus gaederopus, or as the species name suggests - donkeyfoot (gaederopus).
The thorny oyster can become quite large (15cm height) and is mostly always attached on vertical rocks, however I have found one specimen in the sand,attached on a pebble! and the first photograph is a specimen photographed on a very old bivalve shell Pinna nobilis.
This magnificent shell, is mostly found covered by a red sponge (Crambe crambe)and other organisms, so it is well camouflaged for the untrained eye.
The key characteristic of these shells is that their two valves are hinged together by a ball and a socket type hinge, instead of a tooth hinge as is more common in other bivalves. they range from 1 to 50 m depth and can be found out until the Cape Verde Islands.

The photograph above displays a dead oyster, where the sponge has spread inside and outside the valves!
These shells are very good to eat raw, they are treated as a delicacy, and thus their other common name in Greece, the Royal Oyster! However, let me remind you that this shell is a filter feeder, meaning it sieves everything that is in the water,
so, in neolithic Europe, when these were often used for bangles and ornaments, and food as long as 5000 years ago, the seas where pure, crystal clean!No technological revolution, meant anything you ate was safe, nowadays the sea can be a dangerous source of toxins, so keep that in mind before munching on too many.. (Shells of this species have been found in Kastoria-Dispilio (mainland Greece) inside the remnants of the lake city!)

Also, special care must be taken when consuming this oyster in restaurants, if you don't know what a fresh oyster looks like, don't consume, they can be dangerous.