A massive flightless bird that roamed in Queensland, South Australia might have weighed around 600 kilograms, but research revealed that its large skull had little space for a brain.
The Dromornis stirtoni, which stood as high as three meters and lived on a diet of fruit and soft leaves, was very similar to the present-day cassowary, according to researchers at Flinders University.
In their study, fossilized skulls of pre-historic birds were gathered and placed in a CT scanner.
These Dromornis are a popular species among Australian paleontologists and are among the largest of Australia's biggest bird species of "mihirungs" that were left extinct over 50,000 years ago.
Small Room for Pre-Historic Bird's Brain
Researchers CT-scanned five of the very rare fossils of Dromornis skulls using conventional and neutron CT-scanning technology and came up with models of their bird species' brains from the inside. When these fossils were scanned, the researchers compared the space for the Dromornis' brain in each image and found out that there was little room for any brain matter.
They used the skull fossils to extract brain endocasts so they could determine how they compare to modern birds, such as waterfowl and megapodes. CT scans of other Dromornis skulls from fossil sites in Queensland and Northern Territories were also taken.
The oldest fossil came from West Queensland's Riversleigh fossil site, which is among the recognized World Heritage sites that researchers say is critical to the Flinders University study. The skull fossil from Riversleigh dates around 10 million years older than the existing ones under study.
The Flinders study, titled "Endocranial Anatomy of the Giant Extinct Australian Mihirung Birds," which took three years to complete, was part of a more extensive probe into bird paleontology.
While their brains are not similar to birds living today, the 600-kg Dromornis, which are related to chickens and ducks, could also compare to an ostrich or an emu with their similar reliance on good vision for survival, researchers added in a EurekAlert report. They had a size that ranges from a cassowary to the largest ever known bird, with huge, forward-looking eyes, and their upper and lower beaks longer than their skulls.
Weird Evolutionary Experiment
The Dromornis had the largest skull but at the back of its massive bill is its strange cranium that is seen by researchers as a weird evolutionary experiment. To give way to the muscles for the enormous bill, the cranium had become taller, wider than it was long-and this made the brain flattened or tightened to fit.
The large bird species lived in Australia's forests near lakes and river channels for a very long time. Researchers told DailyMail that they are very much excited that modern imaging revealed remarkable details about demornithid morphology that were previously unknown. They are part of the Dromornithidae family, which are also called demon ducks or thunderbirds that existed through the Oligocene through Pleistocene epochs.
Fossil records show that the Dromormis remains were at least 25 million years.
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