A seven-year-old Calgary girl’s curiosity at a local playground has led to the discovery of a rare fossil that may be hundreds of millions of years old.Alyssa was playing at a Calgary park when she began examining medium-sized stacked boulders around the playground’s perimeter. While looking for bugs and collecting rocks, she noticed a dark shape embedded in the top of one of the stones.Fascinated by dinosaurs and palaeontology, Alyssa believed she had found something important and urged her parents to contact experts at the Royal Tyrrell Museum.Museum officials confirmed the discovery was a rare sea star fossil, estimated to be between 250 million and 400 million years old and measuring approximately five centimetres across.Dr. Don Henderson, curator of dinosaurs at the Royal Tyrrell Museum, said sea stars require very specific conditions to fossilize, making specimens of that age extremely rare. He said fossils like Alyssa’s are found at only a handful of sites around the world.The boulder containing the fossil had been placed at the playground when it was built in 2005, meaning the fossil may have sat unnoticed at the park for more than 20 years.Henderson said officials have tried to determine where the boulders were originally sourced, but the exact location has not yet been confirmed.Sitting near the playground where she made the discovery, Alyssa said her favourite part of the fossil was its condition.“I love how preserved it is,” she said.Her parents said the discovery was a proud and exciting moment for their family. They said Alyssa’s passion for palaeontology was evident in the thoughtful questions she brought to the Tyrrell team, including how sea stars fossilize without bones..Henderson said the Royal Tyrrell Museum’s mandate is to preserve Alberta’s fossil heritage, meaning the fossil had to be carefully removed and stored in a controlled environment for research and conservation.Museum staff used a diamond saw to cut into the stone and remove the section containing the fossil while leaving the rest of the boulder in place. City crews are smoothing the area and pouring new concrete to reconstruct the remaining rock.The fossil was taken to the Royal Tyrrell Museum, where it will be cleaned, catalogued and may eventually be placed on display.Alyssa watched the removal from a distance, climbing to the highest point of the playground for a better view. After the rock was lifted out, she was allowed to hold the fossil she had discovered.Laureen Bryant, an archaeologist with the City of Calgary’s Cultural Landscapes group, said fossils in Alberta are protected under the Historical Resources Act.Residents who believe they have found a fossil are encouraged to report it to the Royal Tyrrell Museum, record the location, take photos and leave the fossil undisturbed.City officials praised Alyssa’s commitment to conservation and her enthusiasm for science.As a thank-you, Calgary Parks & Open Spaces presented her with swimming passes, admission to the Calgary Zoo, TELUS Spark Science Centre and Heritage Park, and a tree to plant in memory of the day she uncovered a remarkable piece of Alberta history.