It was getting late and the team of paleontologists excavating a previously unexplored outcrop of the Burgess Shale was ready to call it a day. A camera crew filming the dig in Kootenay National Park had already packed it in. Then one of the team members split open a large plate of shale. “I just remember the gasps all around,” said Joe Moysiuk of the Royal Ontario Museum. “Everyone was running to come and see what had been found. It was clearly a new animal.” What that 2018 dig revealed was something that stood out even in the bizarre world of the Burgess Shale, an outcrop of 500−million−year−old rocks in the Canadian Rockies of British Columbia that is chock−a−block with fossils from the earliest days of complex life on Earth. Most of those fossils are little−finger size. Not this one. “We uncovered this huge carapace,” Moysiuk recalled. “The whole animal …