Dodatak:Popis gmazova, O
Oe uredi
- Oedodera
- Oedura
Og uredi
- Ogmodon
Ol uredi
- Oligodon
- Oligosoma
Om uredi
- Omanosaura
Omoadiphas Köhler, Wilson & Mccranie, 2001 uredi
- Omoadiphas aurula Köhler, Mccranie & Wilson, 2001
- Omoadiphas cannula Mccranie & Cruz-díaz, 2010
- Omoadiphas texiguatensis Mccranie & Castaneda, 2004
Reptilia → Squamata → Colubridae
Oo uredi
- Oocatochus
Op uredi
- Opheodrys
- Ophidiocephalus
- Ophiodes
- Ophiomorus
- Ophiophagus
- Ophioscincus
- Ophisaurus
- Ophisops
- Ophryacus
- Opipeuter
†Opisthodontosaurus Reisz et al., 2015 uredi
- †Opisthodontosaurus carrolli Reisz et al., 2015
- Opisthotropis
- Opluridae
- Oplurus
Or uredi
- Oreocalamus
- Oreocryptophis
- Oriocalotes
- Orlitia
Klada Ornithodira Gauthier 1986 uredi
- Dinosauromorpha Benton 1985
- †Pterosauromorpha Padian 1997
Animalia → Chordata → Reptilia
- Orosaura
- Orraya
- Orthriophis
Os uredi
- Osteolaemus
Ot uredi
- Otocryptis
- Otosaurus
Ou uredi
- Ouroborus
Ov uredi
- Ovophis
Ox uredi
- Oxybelis
- Oxyrhabdium
- Oxyrhopus
Oxyuranus Kinghorn, 1923 uredi
- Oxyuranus microlepidotus (McCoy, 1879) [1] kopneni taipan
- Oxyuranus scutellatus (Peters, 1867) [1] obalni taipan
- Oxyuranus scutellatus canni Slater, 1956 [1]
- Oxyuranus scutellatus scutellatus (Peters, 1867) [1]
- Oxyuranus temporalis Doughty, Maryan, Donnellan & Hutchinson, 2007 [1]