Historic chook tracks on the Wonthaggi Formation in south-east Australia
Martin et al., 2023, PLOS ONE (CC-BY 4.0)
A set of fossilised footprints present in Australia, which date from over 120 million years in the past, are the oldest traces of birds within the southern continents.
The earliest birds advanced from theropod dinosaurs about 150 million years in the past. However fossil proof for birds within the Jurassic and Cretaceous durations is extraordinarily uncommon. “The further back in time, there is less chance of delicate bird skeletons being preserved,” says Julian Hume on the Pure Historical past Museum in London.
That is very true for birds that lived in Gondwana, an unlimited land mass that later broke as much as type South America, Africa, Antarctica, Australia, Arabia and the Indian subcontinent.
Beforehand, the oldest proof for birds in Gondwana was a wishbone and a feather present in south-east Australia, courting again to roughly 118 million years in the past.
Now, Anthony Martin at Emory College in Atlanta, Georgia, and his colleagues have discovered chook tracks that had been made a minimum of 2 million years earlier.
Throughout surveys of the fossil-rich Wonthaggi Formation in Victoria, the group stumbled throughout marks within the floor. “I realised they were bird tracks, which was very exciting,” says Martin. “I knew these must be the oldest bird tracks found in Australia and the southern hemisphere,” he says, because the rocks within the formation date again to between 129 and 120 million years in the past.
The group discovered a complete of 27 footprints, which have a wide range of shapes and measure between 7 and 14 centimetres, suggesting they had been made by various kinds of birds of various ages.
Within the Cretaceous interval, the Wonthaggi was a lot nearer to the south pole than it’s in the present day. However Earth was additionally round 10°C hotter than now, so the local weather would have been much like locations such because the UK, with nice summers and colder winters, says Martin.
The footprints seem in a number of layers of rock representing completely different occasions. As a result of the area would have been chilly and darkish within the winter, the researchers suppose the birds didn’t keep there all yr spherical, however stopped there on a migration route yearly. “They probably felt quite at home there,” says Martin.
“Any evidence of a fossil record, albeit the preservation of bird footprints, is of real significance in the world of avian palaeontology,” says Hume.
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