Here's why:
* Lobe-fins: These fish have fleshy, lobed fins with a bony internal structure, unlike the thin, ray-like fins of other fish. These fins allowed them to move in shallow water and on land.
* Tetrapodomorphs: Within the lobe-finned fish, the tetrapodomorphs possessed features that foreshadowed the transition to land animals. These include:
* Stronger shoulder girdles: For supporting weight on land.
* Bones in the fins: That resembled early limb bones.
* Neck: Giving them greater head movement.
* Lungs: For breathing air.
The most famous example of a tetrapodomorph is Tiktaalik, a fish that lived about 375 million years ago. It possessed both fish-like and tetrapod-like features, bridging the gap between aquatic and terrestrial life.
While it's not possible to definitively pinpoint the single ancestor, tetrapodomorphs represent the closest known fish relatives to the lineage that led to amphibians, reptiles, birds, and mammals.