| class or subclass | order | extant species |
| egg-laying mammals | |
| marsupials | |
| marsupials | |
| marsupials | |
| marsupials | |
| marsupials | |
| marsupials | |
| marsupials | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| | class or subclass | order | extant species |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| placental mammals | |
| marsupials? | |
| lobe-finned fishes | |
| |
|