The discovery of new fossils of Metaspriggina walcotti allowed to shed light on the origin of some of the characteristics of the chordates, animals with a backbone structure which in vertebrates has become the spine. It’s an animal lived about 500 million years ago, during the Middle Cambrian period. Due to their worm-like appearance and a length that could reach 10 centimeters (almost 4 inches), they don’t seem like much but they could be the ancestors of all vertebrates living today.