Ra
- Rabdion
- Rafetus
- Ramphotyphlops
- Rankinia
Re
- Regina
- Rena
Razred Reptilia Laurenti 1768
- †Aenigmasaurus Parrington 1953
- Amblyglossae Fitzinger 1843
- Anapsida Williston 1917
- †Cunichnoides Hitchcock 1858
- †Dravidosaurus Yadagiri and Ayyasami 1979
- †Dravidosaurus blanfordi Yadagiri and Ayyasami 1979
- †Ectocynodon ordinatus Cope 1878
- †Enaliosauria Owen 1839
- †Eupalamopus Hay 1902
- Eureptilia Olson 1947
- †Ganocephala Owen 1861
- Glauconia Gray 1845
- †Gymnarthria Case 1910
- †Herpetichnus Jardine 1850
- †Hyperosauria Jaekel 1910
- †Ichthyosaurus inexpectus Rusconi 1948
- †Ischyrotherium Leidy 1856
- †Isocampe Hitchcock 1858
- †Kintneria Ryan and Willard 1947
- Lyognatha Jaekel 1910
- †Macelognatha Marsh 1884
- †Oolithes Buckman 1859
- †Ornithocephala Bunzel 1870
- †Parareptilia Olson 1947
- †Placodontomorpha
- †Plectropterna Hitchcock 1845
- †Plesiosaurus daedicomus Owen 1840
- †Proganosauromorpha Kuhn 1968
- †Protorosauria Jaekel 1910
- †Puercosaurus Williston 1916
- †Puercosaurus obtusidens Williston 1916
- Rhamphosauria Haeckel 1866
- Rhizodonta Bonaparte 1838
- †Rigalites Huene 1931
- Seps Laurenti 1768
- †Streptosauria Cope 1869
- Testudinata Oppel 1811
- †Tocosauria Haeckel 1866
- †Triaenopus Hitchcock 1845
- †Zhengichnus Zhen et al. 1986
Animalia → Chordata → Tetrapoda → Cotylosauria → Amniota → Sauropsida
Rh
- Rhabdophis
- Rhabdops
- Rhachidelus
- Rhachisaurus
- Rhacodactylus
- Rhadinaea
- Rhadinella
- Rhadinophanes
- Rhadinophis
- Rhagerhis
- Rhamnophis
- Rhamphiophis
- Rhampholeon
- Rheodytes
- Rhinechis
- Rhinemys
- Rhineura
- Rhineuridae
- Rhinobothryum
- Rhinocerophis
- Rhinocheilus
- Rhinoclemmys
- Rhinogecko
- Rhinoleptus
- Rhinophis
- Rhinoplocephalus
- Rhinotyphlops
- Rhoptropella
- Rhoptropus
- Rhynchocalamus
- Rhynchocephalia
- Rhynchoedura
- Rhynchophis
Ri
- Riama
- Rieppeleon
- Riolama
- Ristella
Ro
- Rodriguesophis
Klada Romeriida Gauthier et al. 1988
- Diapsida Osborn 1903