About Spondylus gaederopus Linnaeus, 1758
Spondylus gaederopus Linnaeus, 1758 attaches to its substrate using its lower valve. This lower valve is usually white, while the upper valve is typically purple, though entirely white or entirely purple specimens do exist. This species is distributed only in the Black Sea, the Mediterranean Sea, southern Portugal, and northern Morocco. The closely related species Spondylus senegalensis occupies the range south of this area, and populations found on Madeira, the Canary Islands, and the Azores belong to S. senegalensis. S. gaederopus lives on rocky bottoms from shallow water down to around 50 metres, cementing its right valve to the hard substrate. This species was formerly very common, but its colonies collapsed in the early 1980s for reasons that remain unknown. This mollusc is edible, and it is consumed in Sardinia.
