How Do We Know That This Thing Takes Off From the Ground?

Dmitridon is not a dinosaur, and is more closely related to modern lison. Dimetrodons went extinct forty million years before dinosaurs evolved. The way they walked was really weird. They weren't able to propel themselves with their for limbs. But they might have used them for a little bit of quadrupedal aid,. But they couldn't run and take off. Their wings would hit the ground big. And caras correct, their legs were massive. So you put all that together, that's how they must have taken off, just by jumping into the air and getting a full down stroke with their wings.