Dimetrodon and the sail-backed synapsids
The dominant land predators of the early Permian are closer kin to us than to any reptile.
- When
- Known to
- ± 10 million years
- Era
- Permian, Paleozoic
Pelycosaurs — sprawling, sail-backed synapsids such as Dimetrodon — are the largest terrestrial carnivores of the Cisuralian, reaching over three metres. Despite constant misfiling among the dinosaurs, they predate the first dinosaur by some forty million years and sit on the mammal branch of the amniote tree. The function of the sail, whether thermoregulation or display, is still argued.