What are scyphozoans?

The scyphozoans are an exclusive marine class of the phylum Cnidaria. It may include the extinct fossil group, but its affinities are uncertain and highly debated. Scyphozoans have no durable hard parts, including no head, no skeleton and no specialized organs for respiration or excretion.

These are the jellyfish that are most familiar to beachgoers. Scyphozoans are a very integral part of marine food webs. These jellyfish are radially symmetrical and easily characterized by their bell or medusa shape. All scyphozoans have some stinging capacity, and many are bioluminescent, a feature which can intimidate predators.