Lampreia (Petromyson marinus)

A cyclostome fish that appears occasionally in the seas of Madeira, but to which the island's fishermen do not give any specific name. In addition to its worm-like shape, it has no pectoral or ventral fins, and is equipped with a round mouth and no jaws, with which it forms a kind of suction cup to attach to other species. The sea lamprey usually appears in the rivers of Europe during the spring.