Reptiles return to the sea
Land vertebrates go back into the water and become the ocean's dominant predators for 180 million years.
- When
- Known to
- ± 2 million years
- Era
- Triassic, Mesozoic
Ichthyosaurs appear by around 248 million years ago, followed by nothosaurs, placodonts and later plesiosaurs. Having evolved lungs and limbs on land, these lineages reverse course — limbs become flippers, bodies become streamlined, and ichthyosaurs eventually give birth to live young at sea. Their radiation begins barely three million years after the Great Dying, one of the fastest recoveries in the record.