Dimetrodon among Alethopteris - Dimetrodon among Alethopteris - Artist's view of a dimetrodon among seed...

Dimetrodon among Alethopteris - Dimetrodon among Alethopteris - Artist's view of a dimetrodon among seed ferns (Alethopteris). Dimetrodon is a mammalian reptile (Therapside), carnivore living in Permian. Dimetrodon was the apex predator of its time and likely had few enemies save for other Dimetrodon. They came as large as 11 feet long, 4 feet tall, and weighing as much as 300 pounds. Their reptilian hide, a relative novelty for that period, ensured their survival out of water. The large sail may have helped them to regulate body temperature, a survival advantage during the extremes of hot and cold during the Early Permian. Given that Dimetrodon is more closely related to mammals than dinosaurs, it could be that our own body's ability to regulate temperature had its origin in this ancient beast. Alethopteris was a seed fern that populated much of the world during the Carboniferous and Early Permian periods. Long extinct, fossilized leaves from the Alethopteris are commonly found today