| Taxon | Jaws | Lungs | Claws or nails | Gizzard | Feathers | Fur | Mammary glands | Keratinous scales |
|---|---|---|---|---|---|---|---|---|
| Lamprey (outgroup) | – | – | – | – | – | – | – | – |
| Perch | + | – | – | – | – | – | – | – |
| Salamander | + | + | – | – | – | – | – | – |
| Lizard | + | + | + | – | – | – | – | + |
| Crocodile | + | + | + | + | – | – | – | + |
| Pigeon | + | + | + | + | + | – | – | + |
| Mouse | + | + | + | – | – | + | + | _ |
| Chimpanzee | + | + | + | – | – | + | + | _ |