Tetraphyllidea

Tetraphyllidea is a large tapeworm order that contains some 60 genera and about 800 described species. Tetraphyllideans are remarkable for their scolex morphologies, which are the most varied and morphologically complex amongst all tapeworm orders.

Tetraphyllidean cestodes also exhibit a remarkable degree of host specificity. The procercoid probably parasitizes copepods, which are eaten by the second intermediate hosts: teleost fishes, decapods or cephalopods, which may also serve as paratenic hosts. The verified definite hosts are sharks, skates and stingrays. Occasionally found in cetaceans, the role of these apex predators in the tetraphyllidean life cycle is not well known; whales and dolphins may be definite or dead-end hosts.