Order Hydroida Johnston 1836
Parent taxon: Hydrozoa according to B. M. Waggoner and M. R. Langer 1993
See also Sepkoski 2002 and Taylor 1988
Sister taxa: Actinulida, Delheidia, Fistulella, Graptogeitonia, Hydrocorallinae, Kerunia, Lemniscaterina, Likinia, Limnomedusae, Milleporidae, Milleporina, Narcomedusae, Nigriporellidae, Plumalina, Rhizostromella, Roseoporella, Siphonophorida, Sphaeractinida, Spongiomorphida, Stoliczkiella, Stylasterina, Trachylinida, Tubulariae, Tubuloparietes
Subtaxa: Archaeonectris Calyptoblastina Cambrohydra Chondrophorina Clyxhydra Drevotella Flexihydra Gymnoblastina Inocaulis Lafoeidae Mazohydra Palaeacmea Palaeonectris Parleria Pontifennia Protulophila Psammactinia Rhabdohydra Thecata
Ecology: stationary epifaunal carnivore-suspension feeder