Orange cup coral

Photo: verolam · CC BY-NC

Unlike most Mediterranean corals, Astroides calycularis is an azooxanthellate species — it requires no sunlight and gains all nutrition by catching zooplankton with its neon-orange tentacles. It carpets the ceilings and walls of caves and overhangs, forming some of the most visually striking biological communities in the western Mediterranean. Its range is contracting northward as warming waters shift its thermal envelope, making sites like the Calanques increasingly important reference populations.