Some 50 million years ago, a flightless tropical bird, related to the ostrich, roamed the forests of North America. Researchers discovered a spectacularly well-preserved fossil of the ancient species, known as Calciavis grandei, about a decade ago, but have only recently identified it as a relative of other flightless birds of the ratite family like ostriches, kiwis, and tinamous. Researchers believe the discovery could be the key to identifying other ancient bird species.

The Calciavis fossil was discovered in a former lake bed in Wyoming known for its well-preserved fish fossils. For researchers, the find was momentous: Due to the delicate nature of bird bones, intact ancient bird fossils are incredibly rare. But the Calciavis skeleton wasn’t just intact—some of its feathers and soft tissues were also preserved.

Since its discovery, the Calciavis has remained something of a mystery for researchers. Though it was a spectacular ancient specimen, its taxonomy was unknown. But now, researcher Sterling Nesbitt of Virginia Tech has published a study in the Bulletin of the American Museum of Natural History identifying the Calciavis as an ancient relative of the ostrich.

Nesbit explained in a press statement that tens of millions of years ago, when the fascinating flightless bird was living, North America was a very different place. Nowadays, Wyoming is blanketed in desert sands and sagebrush, but back when the Calciavis roamed the Earth, it was a tropical forest. Nesbit explains that the Calciavis likely went extinct as North America’s tropical forests began to disappear. Today, you’d have to travel to continents like Africa and Australia to find its relatives.

While the identification of the Calciavis fossil is exciting on its own, Nesbit also believes it could aid future research. “The new bird shows us that the bird group that includes the largest flightless birds of today had a much wider distribution and longer evolutionary history in North America,” he said. “This spectacular specimen could be a ‘keystone’ that helps interpret much of the sparse fossil [record] of birds that once lived in North America millions of years ago.”