Concise hierarchy
	(Kingdom) Animalia - (Phylum) Chordata - (Class) Reptilia - (Order) Ichthyornithiformes - (Family) Ichthyornithidae
Included, by definition, in branch-based clade
Current position
	Alternative positions
	
			Historical positions
			
				
					| Ornithurae (Clade) Haeckel 1866 [Gauthier 1986] {Chiappe 1991} | Ref: 
							
								J.K. O'Connor et al., 2010: fig. 9. | 
					
						| †Ichthyornithiformes ([unranked]) Fürbringer, 1888 | Ref: 
								
									K. Padian, 2004: table 11.1 (p. 216), fig. 11.8. | 
						
							| Ornithurae (Clade) Haeckel 1866 [Gauthier 1986] {Chiappe 1991} | Ref: 
									
										L.M. Chiappe, 2001: [126] (fig. 1). | 
							
								| †Archaeornithes (Subclass) Gadow, 1893 | Ref: 
										
											C.M. Perrins, 1991 (1990): 16.
										 [rough position] [indirect] | 
								
									| †Odontognathae (Superorder) Wetmore, 1930 | Ref: 
											
												T.I. Storer et al., 1979 | 
									
										| †Ichthyornithidae (Family) Marsh, 1873 | Ref: 
												
													P. Brodkorb, 1967: 176. | 
									
									Number of Subtaxa