A Big Cousin

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There once walked (and swam) a giant thunderbird in Australia, standing more than eight feet tall and weighing about 36 stone (504 lbs or 228 kg).

Scientists had long thought the extinct animal, Genyornis newtoni, was an ancestor of emus and ostriches. But in the 1990s, paleontologists suggested it was a waterfowl.

Now, a nearly intact fossil skull, between 45,000 and 50,000 years old, has helped confirm that the flightless bird was in fact much closer to geese and ducks.

“Realizing it was an intact skull was just so satisfying,” Phoebe McInerney of Flinders University in Adelaide, South Australia, who led the study based on fossils unearthed between 2013 and 2019 at Lake Callabonna, told the BBC.

The skull find is the first time such a well-preserved fossil was unearthed since the species was first reported in 1872.

And upon examination, McInerney and her team found that the structure of the skull was almost identical to that of the South American screamers, another species of waterfowl.

“They also interestingly have features that allow them to open and close their jaw underwater … without impacting their hearing or (water) going up into their palate or nose,” the paleontologist told the Australian Broadcasting Corp. This was an unexpected discovery, she added.

McInerney and her colleagues wrote that their findings supported a genetic distinction of G. newtoni, arguing that the species should not be considered a close relative of Gastornithidae, another group of prehistoric birds.

Although they had a vegetarian diet, the big birds were probably “tough animals,” McInerney told New Scientist. “They would have been able to defend themselves and would have been quite overwhelming beasts,” she added.

Hunting and egg consumption by the First Nations people, who arrived in Australia about 65,000 years ago, contributed to the species’ extinction, though McInerney argued it would have died out anyway due to climate change.