| Adapinae(noun, fauna, eocene, extinction) |
| Adapisoriculidae(noun, fauna, extinction, paleocene) |
| Afrotarsius(noun, fauna, extinction, oligocene) |
| Alagomyidae(noun, fauna, eocene, extinction) |
| Alamitophis(expression, fauna, extinction, paleogene) |
| Ambulocetidae(noun, fauna, eocene, extinction) |
| Anaptomorphinae(noun, fauna, eocene, extinction) |
| Anconodon(noun, fauna, extinction, paleocene) |
| Araripemydidae(noun, fauna, extinction, paleocene) |
| Archaeohyrax(noun, fauna, extinction, oligocene) |
| Archaeopithecidae(noun, fauna, eocene, extinction) |
| Arctocyon(noun, fauna, extinction, paleocene) |
| Arctocyonidae(noun, fauna, eocene, extinction) |
| Arctostylopida(noun, fauna, eocene, extinction) |
| Asiadapinae(noun, fauna, eocene, extinction) |
| Avitoluvarus(noun, fauna, eocene, extinction) |
| Azibiidae(noun, fauna, eocene, extinction) |
| Baenidae(noun, fauna, eocene, extinction) |
| Baiotomeus(noun, fauna, extinction, paleocene) |
| Bartonian extinction(expression, extinction, period, geochronology) |