The first in a family that would breed the world’s biggest bird ever known has been found by Australian scientists – and it also appears to be a distant kin of ducks.

Researchers from Flinders University and the University of New South Wales revealed their new discoveries on the Dromornis murrayi, a 551-pound flightless bird that now emerges as the earliest ancestor of the Dromornis giant birds, which stood up to 10 feet in height and weighed more than half a ton.

At such heavy weight, the D. murrayi was even the baby in the genus Dromornis, the smallest at a relatively heavy 551 pounds. By 8 million years ago, however, it evolved into D. stirtoni, which was at 992 pounds on average and even reached 1,433 pounds in some cases.

“[They’re] the largest birds the world has known,” reports lead researcher Trevor Worthy.

The D. murrayi existed in the late Oligocene to the early Miocene period, and emerged in research as the first in the lineage of this astounding bird species. Its genus was part of the Dromornithidae family of giant birds called “Mihirungs.”

Mihirungs were huge flightless birds found only in Australia and studied only via fossil species. The largest among them was about 6.6 feet at its back and reached well more than 9.8 feet at its head, added Worthy.

The giant birds lived until the Pleistocene era when the last species, Genyornis newtoni, died out likely about 50,000 years ago.

Researchers have proposed that the Genyornis newtoni became extinct when humans – probably the earliest settlement in Australia – cooked their eggs, as attested to by the birds’ burnt eggshell remains.

The D. murrayi is the newest species recognized after 37 years, and it brings the total number of known mihirungs to eight.

The team arrived at these conclusions after analyzing the skull, breastbone, and leg and foot bones of the fossil. They even examined some tiny bones of the wing, which already demonstrated the fact that by 26 million years ago, the giant bird has practically lost its wings.

Their skull is the weirdest, recalled Worthy. He described it as the bird having had to “run into a brick wall and compressed everything from front to back, so that the bill joined on half way through the eye.”

The findings were published in the Journal of Vertebrate Paleontology.