†order Helodontiformes (chimaera)
Parent taxon: Holocephali according to J. A. Long 2011
Sister taxa: Chimaeriformes, Cranodus, Cymatodus, Debeeriformes, Delphyodontos, Dichelodus, Helodontidae, Helodopsis, Holocephalomorpha, Icanodus, Iniopterygiformes, Macrodontacanthus, Menaspacanthus, Paraselachiamorpha, Physonemus, Platyodus, Ptyktoptychion, Synthetodus, Thoralodus, Venustodus, Xenodus
Subtaxa: none
Ecology: nektonic carnivore