Did the ancestors of sharks swim before the first forests?

Imagine a world with sharks but without trees reverses our spontaneous chronology. The Natural History Museum in London, however, traces an evolutionary history that begins before the first forests. The oldest clues are tiny fossil scales, about 450 million years old.

These remains impose a precaution: specialists are still discussing their attribution to real sharks or related animals. The ancient forms were not copies of the present great white shark. Over time, this vast lineage has produced very different bodies and lifestyles.

Some branches have disappeared, others have gone through major biological crises. The survival of the group does not mean immortality or the absence of evolution. The real surprise is larger than a supposedly unchanged animal: behind modern sharks lies a succession of species whose history goes back to an almost unrecognizable Earth.