Australia's prehistoric ptarmigan, once thought to be an ancestor of the emu, was actually the largest goose that ever lived.

This group was reclassified based on analysis going back 45,000 years. Genyornis neutoni The skull was found in the fossil deposits of Lake Carabonna in the South Australian desert.

The newly discovered skull is the first of the extinct species to be discovered since 1913, and the only one well-preserved enough to allow detailed anatomical study. G. Newton He weighed approximately 230 kilograms and was over 2.5 metres tall.

However, its close relativesDromornis stiltoniAt well over three metres tall and weighing up to 600 kilograms, it is not only a contender for the largest bird in history, but also the largest goose ever.

When Thunderbird fossils were first discovered in the 19th century, they were thought to be ancestors of ratites, which include emus, cassowaries and ostriches. Later, some argued that the group, officially called Dromornithiidae, with eight known species, should be classified with land birds, which also include chickens and pheasants.

now, Phoebe McInerney Researchers from Flinders University in Adelaide, Australia, concluded that the Thunderbird is a large waterbird and should be classified as part of the Anseriformes, the same group as geese.

The team was primarily convinced by the anatomy of the beak and skull, including the arrangement of muscles and the deformation of the bones to which they were attached. Genyornis The structure is nearly identical to that of South American screamers, an ancient lineage of waterbirds, and is so complex that it's unlikely it evolved independently, McInerney said.

All of the ptarmigans were herbivores, she says, but they were probably fierce creatures. “They would have been very tough animals,” McInerney says. “They could defend themselves and they would have been quite formidable beasts. They would have had a very low, loud cry.”

Adam Yates Yates, of the Northern Territory Museum and Art Gallery in Australia, said the study supports the claims of his predecessor, Peter Murray, who proposed in the early 1990s that the Thunderbird was a waterbird. “So it's not a shock to me,” Yates said. “But Genyornis It took so long to find the skull, so we're very happy that it has finally been found.”

Many Thunderbird species became extinct before humans arrived in Australia around 65,000 years ago, which is thought to have been due to climate change.G. Newtoni Humans had inhabited the continent for tens of thousands of years, and some researchers speculate that hunting may have also played a role in their extinction.