The Early Cambrian Fossils

Exceptional fossil deposits at the Chengjiang site, dating to approximately 520 million years ago, have preserved soft tissues of diverse early Cambrian animals, revealing key insights into the rapid evolutionary radiation and anatomical diversification during this period. These fossils, including sponges, polyps, and bilaterians such as arthropods, demonstrate the growing separation of visceral organs from somatic features like limbs, fins, brain, and eyes. The Chengjiang community represents a global pattern, with earlier deposits at Kuanpuanchu indicating that this radiation began 15 million years prior. Additionally, even older Siberian fossils show evidence of predator-prey distinctions, suggesting complex ecological interactions had already evolved by the base of the Cambrian.

Bell, G. (2026). The Early Cambrian Fossils. The Sea-Change, 96–148. https://doi.org/10.1093/9780197797464.003.0009