Abstract
The class Hydrozoa is the most speciose among the Medusozoa, and includes the greatest diversity of cnidomes and life cycles among the Cnidaria. Yet, the phylogenetic relationships of hydrozoan groups are still poorly understood, what hinders comparative studies of model organisms (e.g., Hydra) and of the evolution of polypoid and medusoid characters. Estimating the phylogeny of hydrozoa…