518-Million-Year-Old Fossil Reveals Origins of Spider Fangs

Half a billion years before the first spider spun its first web, a creature smaller than a thumbnail was already carrying the blueprint for one of nature's most successful predatory tools. Researchers from Yunnan University and the University of Leicester have identified Urokodia, a 518-million-year-old marine fossil from southern China, as the earliest known ancestor of chelicerates — the vast group that includes spiders, scorpions, ticks, and horseshoe crabs. Hidden within the stone for millennia, its pincer-like limbs were only revealed through X-ray tomography, offering science a rare glim