Order Hexanchiformes de Buen 1926 (elasmobranch)
Chondrichthyes - Squalomorphii
Parent taxon: Squalomorphii according to D. Thies 1983
Sister taxon: Synechodontiformes
Subtaxa: Chlamydoselachidae, Eonotidanus, Hexanchidae, Pachyhexanchus, Paraheptranchias, Paranotidanus, Pseudonotidanidae, Thrinax, Welcommia, Weltonia
Ecology: nektonic carnivore