Phylogenetic relationships among orders within the Class Scyphozoa.
Based on Collins (2002).

Molecular data suggest strongly that the coronates, semaeostomes, and rhizostomes form a monophyletic clade. The coronates are distinct from the semaeostomes and rhizostomes, whereas the semaeostomes are paraphyletic with respect to the rhizostomes (i.e. evolutionarily, rhizostomes are a type of semaeostome, rather than a distinct form of jellyfish).

In contrast, the data provide conflicting information regarding the evolutionary placement of the Stauromedusae. They may (1) be closely related to the Cubomedusae with which they may form the sister taxon to the other scyphozoans or (2) be basal to the other Scyphozoans, the Cubozoa, and the Hydrozoa.