On Jun. 11, 2020, scientists at the Universities of Oxford, Exeter, Yunnan and Bristol announced thay had discovered the oldest fossil of the group of animals that contains earthworms, leeches, ragworms and lugworms. This discovery, published in Nature, pushes the origin of living groups of these worms (polychaetes) back tens of millions of years, demonstrating that they played an important part in the earliest animal ecosystems.

The fossil specimens are approximately 514 million years old and come from eastern Yunnan Province in China, originating from a geological time known as the early Cambrian. These rocks provide crucial fossil evidence of the dawn of early animal life, known as the ﾓCambrian Explosionﾔ.