A Classification Vertebrates and Their Relatives
Kingdom: Animalia
Superphylum Protostomia
Phylum: Mollusca
Phylum: Arthropoda
Phylum: Annelida
Superphylum: Deuterostomia
Phylum: Chaetognatha
Phylum: Echinodermata
Subphylum: Calcichordata = (?) 2
Phylum: Hemichordata
Class: Enteropneusta
Class: Pterobranchia
Phylum: Chordata
Subphylum: Tunicata (Urochordata)
Class: Ascidiacea
Class: Thaliacea
Subphylum: Cephalochordata
Subphylum: Vertebrata (Craniata) 3
Superclass: Conodontophorida = (?)
Superclass: Agnatha
Order: Myxiniformes
Order: Petromyzontiformes
Order: "Ostracoderm" 4
Superclass: Gnathostomata
Class: Placodermi =
Class: Chondrichthyes
Subclass: Elasmobranchii
Class: Osteichthyes
Subclass: Actinopterygii
Infraclass: Neopterygii
Division: Teleostei
Subclass: Sarcopterygii
Order: Coelacanthiformes
Order: Dipnoi (?) 5
Order: Osteolepimorpha (Rhipidistia) =
Subclass: Tetrapoda
Class: Amphibia
Subclass: Labyrinthodontia =
Order: Ichthyostegalia
Subclass: Lissamphibia
Order: Anura (Salientia)
Order: Urodela (Caudata)
Order: Gymnophonia (Caecilia)
Superclass: Amniota
Superdivision: Synapsida
Division: Pelycosauria =
Division: Therapsida
Class: Mammalia
Subclass: Prototheria (Monotremata)
Subclass: Theria
Infraclass: Metatheria (Marsupialia)
Infraclass: Eutheria (Placentalia)
Order: Insectivora
Order: Carnivora
Order: Chiroptera
Order: Primates
Order: Rodentia
Order: Lagamorpha
Order: Perissodactyla
Order: Artiodactyla
Order: Cetacea
Class: Reptilia
Order: Chelonia (Testudines)(?)
Division: Diapsida
Subclass: Lepidosauria
Order: Rhynchocephalia
Superorder: Squamata
Order: Amphisbaenia
Order: Lacertilia
Order: Serpentes (Ophidia)
Subclass: Archosauria
Order: Crocodilia
Order: Pterosauria =
Order: Dinosauria
Suborder: Ornithischia =
Suborder: Saurischia
Cohort: Aves
= Indicates extinct taxon.
1 Follows basic classification provided by: Walker, W.F. and K. F. Liem., 1994. Functional Anatomy of the Vertebrates, 2nd Ed. Saunders College Publ. Ft. Worth; with modifications based on: Kemp, T. S. 1982. Mammal-like Reptiles and the Origin of Mammals. Academic Press, NY.; Nelson, J. S. 1994. Fishes of the World, 3rd Ed. John Wiley and Sons Inc., NY; Wiley, E. O. 1981. Phylogenetics: The Theory and Practice of Phylogenetic Systematics. John Wiley and Sons, NY; Pough, F. H., Janis, C.M., and Heiser, J. B. 1999. Vertebrate Life, 5thEd. Prentice Hall.
2 A question mark (?) indicates: A) that the placement of a taxon in this position is questionable or debatable and that some authors may place that taxon in a different position; or B) that taxon may not represent a monophyletic group.
3 Names in parentheses represent alternative names that are often used for a particular taxon.
4 This is a paraphyletic taxon. I use the term here simply to follow the usage in the textbook.
5 There are arguments as to who is really the sister taxon to the tetrapods; the alternative hypothesis is that the Dipnoi are the sister taxon to tetrapods.
