A 500-million-year-old clawed predator rewrites the origin of spiders and horseshoe crabs

A 500-million-year-old clawed predator rewrites the origin of spiders and horseshoe crabs It had been a long day of teaching for Rudy Lerosey-Aubril. As a reward, he returned to cleaning an intriguing Cambrian arthropod fossil he had recently received for review. At first, the specimen showed all…