Therapsids, the proto-mammals
c. 275 million years ago · Event
The synapsid line upgrades: therapsids stand with legs under the body rather than sprawled, and their later members — the cynodonts — add differentiated teeth, warm blood and probably whiskers and fur. They rule the late Permian world, are nearly annihilated in the Great Dying, and spend the whole dinosaur age as their small nocturnal heirs: the first true mammals of 225 million years ago are their direct descendants.
On these timelines: Master, The Age of Dinosaurs
Around 275000000 BCE
- Permian–Triassic extinction (252000000 BCE)
- Mesozoic Era (252000000 BCE)
- Triassic Period (252000000 BCE)
- Permian Period (299000000 BCE)
- Dimetrodon (295000000 BCE)
- Archosaurs emerge (250000000 BCE)
- Lystrosaurus (252000000 BCE)