Ipswich, about 40 kilometres west of Brisbane, appears an unlikely place to seek out dinosaur fossils. But the world has produced the oldest proof of dinosaurs in Australia.
A contemporary have a look at these fossils now reveals they aren’t what they first appeared, and it’s prompting us to rethink how the story of Australia’s dinosaurs started.
In analysis printed at this time in Historic Biology, we reanalyse a sequence of 220-million-year-old tracks from the Ipswich Coal Measures, thought to have belonged to a carnivorous dinosaur.
We present they really belonged to an early sauropodomorph — a distant relative of the plant-eating sauropods that roamed the planet a lot later, through the Jurassic and Cretaceous intervals. This the primary time fossil proof of early sauropodomorphs has been present in Australia.
Subterranean dinosaur tracks
The Ipswich space was as soon as the principal supply of coal for Queensland. Its suburbs together with Ebbw Vale, New Chum and Swanbank have been dotted with underground mines through the late 1800s and the primary half of the 20 th century.
These mining operations concerned the creation of deep shafts and tunnels, from which miners might entry deposits of coal sandwiched between different layers of rock. Some tunnels would descend tons of of metres beneath the floor.
The coal could be faraway from the seam by hand, and pillars have been left as an alternative to assist the ceiling of the ensuing underground “room”. It was tough and harmful work.
In 1964, miners working on the Rhondda colliery in New Chum made a startling discovery. As they eliminated the coal from a seam they have been following 213 metres beneath the floor, a collection of big, three-toed tracks turned uncovered within the ceiling of the mine shaft. For the miners, it was as if a dinosaur had simply walked over their heads.
Steven Salisbury, Writer offered
These tracks stay the oldest-known dinosaur fossils in the whole continent. They’d been made by a dinosaur strolling throughout a layer of swampy vegetation, which might be extracted as coal 220 million years later. Buried below tremendous silt and dust, they’d been preserved as pure casts.
It had been assumed some kind of predatory dinosaur made the tracks. The one downside was the footprints have been reportedly about 40–46 centimetres lengthy. This could counsel the track-maker was slightly below 2m excessive on the hips.
This isn’t essentially massive for a theropod resembling Allosaurus fragillis, which was about this dimension. Tyrannosaurus rex was even greater, with a hip top of about 3.2m.
However the tracks present in Ipswich have been created through the Late Triassic about 220 million years in the past — 65 million years earlier than Allosaurus and 150 million years earlier than T. rex. And fossil proof from world wide signifies theropods of a bigger dimension didn’t seem till the beginning of the Early Jurrasic Interval, 200 million years in the past.
Was one thing uncommon afoot in Australia through the Late Triassic?
As a part of a broader assessment of Australian dinosaur tracks, we determined to take a more in-depth have a look at the Rhondda colliery tracks. The mine has lengthy been closed, so the unique tracks are not accessible, however archival images and a plaster forged are held on the Queensland Museum.
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Utilizing the photographs and forged, we created a 3D digital mannequin of the observe to permit a extra detailed comparability with different dinosaur tracks from world wide.
Our examine revealed two vital issues. First, the footprints weren’t as huge as initially reported. Excluding drag marks and different unrelated floor options, they’re near 32–34cm lengthy (not 40–46cm as beforehand documented).
Second, the form of the footprints and the sequence through which they have been made is extra according to early sauropodomorphs. Sauropodomorphs have been the distant kin of the lumbering sauropods of the Late Jurassic and subsequent Cretaceous Interval.
The towering Triassic terror of the Ipswich Coal Measures was no extra. As an alternative was a peaceable plant-eater.
The stays of early sauropodomorph dinosaurs have been present in Higher Triassic rocks, aged between 220 million and 200 million years, in continental Europe, Argentina, Brazil and South Africa.
And by the beginning of the Jurassic, 200 million years in the past, they’d achieved a close to international distribution, with fossils in North America, China and Antarctica. This isn’t stunning, given the continents on the time have been nonetheless related in a single landmass known as Pangaea.
Our new interpretation of the Rhondda colliery tracks reveals early sauropodomorphs lived in Australia, too, and that Australia’s first dinosaurs have been friendlier than we thought.
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