Bipedal and quadrupedal refers to a shift from using two legs to four legs, by the way. It continues: “Here, we use virtual analytical methods to reconstruct the endocast of extinct dinosaurs ...

Lesothosaurus was small, agile, and bipedal, bearing seemingly little resemblance to the gigantic, quadrupedal ornithischians that came later. But physical features, such as hip structure and jaws ...