Clade Lepidosauria Haeckel 1866 [de Queiroz & Gauthier 2020]
see Subclass Lepidosauria Duméril & Bibron, 1839
Clade Rhynchocephalia Günther 1867 [Gauthier, Estes & de Queiroz 1988]
see Order Rhynchocephalia Günther, 1867
Clade Sphenodontia Williston 1925 [Evans 2003]
Clade Acrosphenodontia Chambi-Trowell, Martinelli, Whiteside, Romo de Vivar, Soares, Schultz, Gill, Benton & Rayfield 2021
Clade Eusphenodontia Herrera-Flores, Stubbs, Elsler & Benton 2018
Genus †Opisthiamimus DeMar, Jones & Carrano, 2022 [monotypic]
1 †Opisthiamimus gregori DeMar, Jones & Carrano, 2022