Tetrapods moved from sea to land astonishingly briefly
The story of all land animals begins with a squat-limbed, long-bodied swamp fish. Sometime in the steamy mid-Devonian, a family of those fish followed plants and bugs onto land and became the first tetrapods, or four-legged vertebrates. But the fossil record from 390 million years ago is so sparse that it’s hard to find clues