Absolute gem of a find: Opalised dinosaur fossil studied using innovative 3D printing technology

Palaeontologists at Adelaide’s Flinders University have used cutting edge micro-CT scanning and 3D printing technology to look inside a 100-million-year-old dinosaur fossil. But this was no ordinary fossil.

In a rare find, collectors unearthed fossils of a small dinosaur which had opalised. They believe it might be a new species of Australian dinosaur.

The dinosaur was a small bipedal herbivore called a hypsilophodont. The fossils were found in the opal mining town of Lightning Ridge, in outback New South Wales and were recovered and rescued for scientific study in 2019.

A collaboration between the Australian Opal Centre at Lightning Ridge and the Palaeo Pictures documentary team led by Paul Willis, associate professor at Flinders University, will see the dinosaur reconstructed from the opalised fossils.

Lead palaeontologist Assoc Prof Paul Willis mounts specimens in stacks of polystyrene ahead of scanning. Credit: Palaeo Pictures.

Opals are formed when silicon dioxide dissolved in water trickles through the Earth until it reaches cavities in rocks. Once the water evaporates, a silica deposit is left behind.

Read more: Mini yet mighty: New two-legged, armoured dinosaur found in Argentina is the first of its kind

Sometimes, the cavities in which opals form are there because a living thing was buried in sand or clay before it hardened into stone. The opal forms in the mould leaving behind the fossil replica of the creature.

The bones are preserved as common opal, or potch, and are mostly embedded within a white sandstone. Credit: Palaeo Pictures.

Fossils found at Lightning Ridge are often colourless and “valueless” (monetarily speaking) potch. But occasionally the fossils are composed of precious opal – even the treasured black opal – and are very high in value.

But Willis insists that all fossil specimens are “priceless” to science.

His team has begun using the latest imaging technology to learn more about the animal that left the impressions behind.

“We’re using the Flinders CT Scanning Facility at Tonsley to look inside lumps of rock that contain the remains of a small dinosaur,” says Willis. The scans show the fossil preserved in exquisite detail.

“Not only do the scans allow us to better understand exactly what we have as a dinosaur skeleton, they will be an invaluable aid to the next stage of studying this specimen, by removing the surrounding rock.

“Prior to using scans on specimens like this, the removal of surrounding rock was very much a case of ‘doing it blind’, feeling our way in to reveal the bones. Now we can do that with more confidence because we know where the rock stops and the bone starts.” 

Around 20% of the fossil specimens have been scanned so far. Once the rest are processed the team will work on a detailed study of the skeleton and produce, using 3D printing, as complete a reconstruction as possible from the puzzle pieces.

On the right is the opal fossil still in the rock and on the left is a 3D print of the fossil generated from the CT scans. Credit: Palaeo Pictures.

The palaeontologists hope the reconstruction will reveal if this is indeed a new species of dinosaur, and they will then try to give “life” back to the fossils by learning about how the animal lived and died.

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