Beginning with an excavation in 1984, an opal mine in Lightning Ridge (in rural New South Wales, Australia) suddenly became a hotbed for fossilized—and subsequently opalized—dinosaur bones. While the original team assumed the abnormally large and centralized collection of bones came from one body, researchers are now learning they are bones from multiple dinosaurs and an entirely new species—implying that a herd, which is now the first-ever found in Australia, roamed there. “The discovery of dinosaur groups unique to the Southern Hemisphere suggests that our current understanding of dinosaur evolution is incomplete,” says Ralph Molnar, a paleontologist at the Museum of Northern Arizona in Flagstaff. This discovery ultimately changes the commonly told history of prehistoric times. Read more at SmithsonianMag.