https://www.wired.com/story/a-crocodile-like-robot-helps-solve-a-300-million-year-mystery/

Nearly 300 million years ago, a curious creature called Orobates pabsti walked the land. Animals had just begun pulling themselves out of the water and exploring the big, dry world, and here was the plant-eating tetrapod Orobates, making its way on four legs. Paleontologists know it did so because one particularly well-preserved fossil has, well, four legs. And luckily enough, scientists also discovered fossilized footprints, or trackways, to match.

The assumption has been that Orobates—a cousin of the amniote lineage, which today includes mammals and reptiles—and other early tetrapods hadn’t yet evolved an “advanced” gait, instead dragging themselves along more like salamanders. But today, in an epically multidisciplinary paper in Nature, researchers detail how they married paleontology, biomechanics, computer simulations, live animal demonstrations, and even an Orobates robot to determine that the ancient critter probably walked in a far more advanced way than was previously believed possible. And that has big implications for the understanding of how locomotion evolved on land, not to mention how scientists study the ways extinct animals of all types got around.