Rheiformes (Rheas)
Family: Rheidae
| Scientific Name | Author/s | Common Name | Last Record | Distribution | Status | Taxon Profile |
| Rhea fossilis | Ameghino, 1882 | Fossil rhea | Late Pleistocene | Argentina | Extinct | Access |
| Rhea nana | Lydekker, 1894 | Dwarf rhea | 1894 or before | Patagonia, Argentina | Invalid (synonym) | Access |
| Rhea pampeana | Moreno and Mercerat, 1891 | Pampean rhea | Late Pleistocene | Argentina | Extinct | Access |