You are in the forested floodplains of China, 135 million years ago.

The air in the early Cretaceous floodplain was humid, thick with the scent of ferns—not the dry pine scent of the Jurassic. You crouched low behind a thick, fleshy cycad, your binoculars trained on the edge of the misty forest.

That’s when I saw it. It wasn't just any towering, dramatic silhouette of a stegosaur. It was lower, broader, and quieter.

A Wuerhosaurus.

It was magnificent in its own way. Nearly 8 meters long, its back was arched, and the plates running along its spine weren't high triangles, but long, low, rectangular sails, perhaps meant for display in this new, greener world. Its skin was armored and textured, mottled with shades of brownish-green to match the thick ferns. It was feeding, moving its head close to the ground, munching on a small, soft bush.

For a moment, it stopped, sensing something. Its massive tail, with four long spikes at its end, swiveled slowly, a silent threat to any predator stalking it.