| Extant Thanetian first appearance(expression, appearance, period, geochronology) |
| Aequornithes(noun, animal, geohistory, appearance) |
| Afroaves(noun, animal, geohistory, appearance) |
| Afrotheria(noun, animal, geohistory, appearance) |
| Aldrovanda(noun, animal, geohistory, appearance) |
| Alligatorinae(noun, animal, geohistory, appearance) |
| Ampullinopsis(noun, animal, geohistory, appearance) |
| Andrias(noun, animal, geohistory, appearance) |
| Anguillidae(noun, animal, geohistory, appearance) |
| Apodiformes(noun, animal, geohistory, appearance) |
| Astraea(noun, animal, geohistory, appearance) |
| Atlantogenata(noun, animal, geohistory, appearance) |
| Australidelphia(noun, animal, geohistory, appearance) |
| Bathytoma(noun, animal, geohistory, appearance) |
| Boidae(noun, animal, geohistory, appearance) |
| Boinae(noun, animal, geohistory, appearance) |
| Bonefishes(noun, animal, geohistory, appearance) |
| Budgerigar(noun, animal, geohistory, appearance) |
| Caiman(noun, animal, geohistory, appearance) |
| Callichthyidae(noun, animal, geohistory, appearance) |