| Notohippidae(noun, fauna, extinction, chattian) |
| Notostylopidae(noun, fauna, extinction, rupelian) |
| Oligocene genus extinction(expression, extinction, period, geochronology) |
| Oligopithecidae(noun, fauna, extinction, rupelian) |
| Otarocyon(noun, fauna, extinction, chattian) |
| Palaeocarpilius(noun, fauna, extinction, rupelian) |
| Paratylopus(noun, fauna, extinction, rupelian) |
| Philotrox(noun, fauna, extinction, chattian) |
| Phiomia(noun, fauna, extinction, rupelian) |
| Poebrotherium(noun, fauna, extinction, rupelian) |
| Presbyornithidae(noun, fauna, extinction, rupelian) |
| Priscocamelus(noun, fauna, extinction, chattian) |
| Proborhyaenida(noun, fauna, extinction, chattian) |
| Pycnodontidae(noun, fauna, extinction, lutetian) |
| Pycnodus(noun, fauna, extinction, lutetian) |
| Sinopa(noun, fauna, extinction, rupelian) |
| Spathorhynchus(noun, fauna, extinction, rupelian) |
| Subhyracodon(noun, fauna, extinction, chattian) |
| Sunkahetanka(noun, fauna, extinction, chattian) |
| Theelia(noun, fauna, extinction, lutetian) |