The Cambrian Explosion saw most major animal phyla appear suddenly in the fossil record. Continents were largely scattered across the southern hemisphere and trilobites flourished in the seas.
Explore the Cambrian Earth in 3D →The Cambrian began about 538.8 million years ago. Over roughly its first 20 million years, animal body plans and ways of life diversified rapidly. Some lineages already existed in the Ediacaran, so this “explosion” was an extended diversification, not an instant origin of life.
Some roughly 518-million-year-old myllokunmingiids, early jawless vertebrates from China, had two large lateral eyes and two smaller central eyes. A 2026 study identified pigment and lens-like structures in the extra pair, supporting image-forming vision.