Mitrocomella polydiademata is a leptomedusa hydrozoan (family Mitrocomidae) found in cold temperate and boreal oceanic waters, bearing multiple statocyst-bearing structures arranged in clusters around the bell margin providing excellent equilibrium sensing in the pelagic zone. The species is a planktonic predator of small crustaceans and invertebrate larvae. Its phylogenetic position within Leptothecata makes it valuable for comparative studies of hydrozoan medusa evolution and sensory system development. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.