The Chengjiang biota from eastern Yunnan in China are one of the most significant Lower Cambrian fossil assemblages in the world. The sediments containing the Chengjiang fossils were deposited in a shallow marine setting on the Yangtze Platform, which, during this period, was situated near the equator.

This diverse range of organisms provides clues to rapid evolution during the Cambrian Explosion and reveals information on modes of life in a complex ancient ecological system. Diversification meant that animals were already developing new ecological niches and strategies such as active swimming and hunting, pelagic as well as benthic lifestyles, and crawling on the seabed or burrowing deeply into sediments.