The first in a line of birds that would culminate with the world’s biggest bird ever has been discovered in Australia.

Researchers from Flinders University and the University of New South Wales have just published a study in the Journal of Vertebrate Paleontology detailing their findings on the flightless, 551-pound Dromornis murrayi, now the earliest known species in the genus Dromornis -- prehistoric birds that stood up to 10 feet tall and could weigh more than half a ton.

Giant Flightless Bird Once Roamed The Arctic

Believe it or not, even at that weight D. murrayi was the baby of the Dromornis line.

“Originally, it was the smallest, at a pretty hefty 250 kilograms [551 pounds],” said the study’s lead author Trevor Worthy. “But by eight million years ago it had evolved into D. stirtoni, which averaged a whopping 450 kilograms [992 pounds], with some individuals reaching 650 kilograms [1,433 pounds] — the largest birds the world has known.”

The new bird D. murrayi lived during the late Oligocene to early Miocene. Its Dromornis genus belonged to the Dromornithidae family of huge birds also known as "Mihirungs."

“Mihirungs were giant flightless birds only found in Australia and are known only from fossils,” explained Worthy. “The largest stood two meters [6.6 feet] high at its back and reached well over three meters [9.8 feet] at the head."

“They survived until the Pleistocene period when Genyornis newtoni, the last species, died out, probably about 50,000 years ago,” he added.

Fossil Could Settle Debate Over Flight In Earliest Birds

“The very large and distinctive bones of this new ‘Big Bird’ are quite common in the Riversleigh [northwest Queensland, Australia] fossil deposits, and are easily spotted by scientists and visitors to the site,” said study co-author Suzanne Hand, of the University of New South Wales.

The researchers realized the new bird was an ancestor of the hulking D. stirtoni after poring over skull, sternum, and breast bones as well as bones from the leg and foot of the giant bird.

“We even had some tiny bones of the wing, which showed this gigantic bird had already, by 26 million years ago, essentially lost its wings,” said Worthy.