Scientists in China have unearthed remarkably well-preserved trace fossils of a giant horseshoe crab dating back 240 million years. The fossils, belonging to a crab reaching 70cm in length, provide new insight into the locomotion of these ancient creatures. Researchers found that ancient horseshoe crabs swam differently compared to their modern counterparts. This discovery offers valuable information regarding the recovery of marine life following Earth’s most devastating mass extinction event. The findings suggest a unique evolutionary pathway for horseshoe crabs. These fossils contribute to understanding the resilience and adaptation of life after catastrophic events in Earth’s history, illuminating the ancient marine ecosystems of China.