Molecular phylogenetics
Along with the Warnowiaceae (warnowiids), polykrikoids are known for possessing unusually complex subcellular structures. In particular, an extrusome complex of two organelles called the nematocyst and taeniocyst is considered a synapomorphy for "Polykrikos". Molecular phylogenetics studies suggest some inconsistency in the taxonomy of this group, particularly in the assignment of species to one of the two genera.