PRONUNCIATION | Die-MET-roe-don
SPECIES | Dimetrodon grandis
NAME | Two Measures of Teeth
FAMILY | Sphenacodontidae
PERIOD | Early Permian
DIET | Carnivore
SIZE | 15 feet (5m)
YEAR DISCOVERED | 1878
Dimetrodon is perhaps the most famous dinosaur that is not actually a dinosaur—it went extinct 40 million years before the first appearance of dinosaurs. It is in the synapsids group and is more closely related to mammals than dinosaurs. These meat-eating mammal-like reptiles were the apex predators of the time before dinosaurs. Their name “Two Measures of Teeth” refers to the combination of large biting fangs at the front of the mouth and the grinding canines in the rear, not dissimilar from a cat or dog of today.
With a wide reptilian stance, dimetrodon would have had a whiplike gait and run much like a crocodile or Komodo dragon. It was possibly capable of short bursts of speed.
The dimetrodon is most famous for the large sail along its spine used for regulating temperature. This blood-filled sail might have also been capable of changing colors, such as brightening in danger to ward off a threat or to attract a mate, not unlike a peacock’s tail. Various other species in dimetrodon’s Sphenacodontidae family ranged in size from large crocodiles to medium-sized lizards.
Dimetrodon was a carnivore. Its massive bull-like head was filled with large teeth similar to that of an alligator. The small eyes perched high on its head and large nasal cavity suggest the dimetrodon was a lurking hunter that possibly waded in shallow water, locating its prey by smell.
A common prey of dimetrodon, the diplocaulus was a large amphibian with a boomerang-shaped head. This salamander-like creature would have been common throughout the swamps and waterways of the Permian period feeding on small fish and giant insects. Its large, flat body would allow it to glide through muddy shallows.
Diplocaulus magnicornus
Length 3 feet (1m)