New study reveals evolutionary history of Australia’s gigantic ancient bird
A flightless, plant-eating bird, mihirungs weighed 250kg and lived in the late Oligocene to the early Miocene, about 33 to 20 million years ago.
A LOT ABOUT the Mihirungs— an ancient group of birds unique to Australia—remains a mystery. But in a study released today, scientists seem to be getting closer to revealing the birds’ evolutionary history.
Prior to this most recent study undertaken by Flinders University palaeontologist Trevor Worthy, which examined the subtle features of various bird fossil bones, it was understood that these giant birds — often weighing over 600kg — were closely related to the waterfowl (Anseriformes).
Instead, Trevor says that the mihirungs, as well as a species of bird known as Gastornis, were the last survivors of a far flung group belonging to the Galloanseres family.
“The most important aspect of our study is the recognition that the Galloanseres, the group that includes waterfowl and landfowl, had in the past included another two major group of birds, thereby substantially adding to their morphological diversity,” he says.
“The mihirungs and gastornithids are a part of one these two new groups and while they died out elsewhere about 50 million years ago, in Australia, they very nearly made it to the modern world with the last mihirung going extinct about 50,000 years ago.”
The second group of birds belonging to the Galloanseres family — known as Vegavis is the only ‘modern’ bird that has existed when dinosaurs roamed the earth. “Its form perhaps reveals what the ancestor of modern birds look like,” Trevor says.
Trevor says that following on from his most recent study he wants to focus in on the ancient birds’ anatomy. “We want to look into the function of the giant skull and understand what it was used for. Also we want to determine things about their biology such as how long they lived, or how long they took to mature, and so determine what led to their extinction.”