The newly discovered species, Archaehierax sylvestris, is one of the oldest eagle-like raptors in the world, according to a study published Monday in the peer-reviewed journal, Historical Biology. Paleontologists from Adelaide’s Flinders University unearthed the fossil in March 2016 on a remote outback cattle station during a research trip at Lake Pinpa in South Australia.
With feet nearly 15 centimeters (6 inches) long, the eagle would have had the ability to grasp large prey. The scientists said it would have hunted an extinct species of koala, which was about the same size as those alive today, as well as possums and other animals in trees, the study said.
“The largest marsupial predators at the time were about the size of a small dog or large cat, so Archaehierax was certainly ruling the roost,” Ellen Mather, author of the study and Flinders University postdoctoral candidate, said in a statement.
The partial fossil skeleton is comprised of 63 bones, making Archaehierax sylvestris one of the best preserved species found around Lake Pinpa. The completeness of the skeleton allowed researchers to determine where it fits on the eagle family tree, Mather said.
“It shows a range of features unlike any seen among modern hawks and eagles,” she said. “It seems to have been its own unique branch of the eagle family.”
The fossil bones reveal that the wings of the species were short for its size, which made them quite agile and allowed them to dodge trees while it hunted. Its legs were relatively long, which would have given it considerable reach.
Scientists did not say why or when the species went extinct.
The Australian environment during the Oligocene was vastly different to today. Lake Pinpa, where the fossil was found, was once a lush ecosystem covered in trees and forests, the study said. Today, it is barren, dry and desolate.
Trevor Worthy, associate professor at Flinders University and co-author of the study, said in the statement that it is rare to find even one bone from a fossil eagle. This is likely due to a number of reasons, Mather added, including that bird bones can be quite fragile, which makes them easier to break.
“To have most of the skeleton is pretty exciting, especially considering how old it is,” Worthy said.
Researchers have made a number of fossil discoveries in Australia over the years, shedding light on the diversity of species that roamed the Earth eons ago.