A heavily armoured dinosaur whose remains were found in a Suncor mine in Canada used camouflage to hide from predators despite being built like a tank, say scientists.
Fossilised remains of the creature found in the mine were so well preserved experts have been able to determine the colour of its scaly skin.
Borealopelta markmitchelli, which lived 110 million years ago in the Cretaceous period, was 18ft (5.5m) long and weighed a hefty 1.3 tonnes (2,800 pounds).
Chemical analysis showed that the dinosaur would have had reddish brown knobbly skin and countershading – a common form of camouflage seen in animals with dark backs and lighter undersides.
“Strong predation on a massive, heavily-armoured dinosaur illustrates just how dangerous the dinosaur predators of the Cretaceous must have been,” said lead researcher Dr Caleb Brown from the Royal Tyrrell Museum of Palaeontology in Alberta.
The Cretaceous was a time when giant theropods, meat-eating dinosaurs that stood on two legs, roamed the Earth.
Although the king of them all, Tyrannosaurus rex, lived millions of years after Borealopelta, the armoured dinosaur may have been hunted by some of its formidable ancestors. They include Acrocanthosaurus, a 38ft (11.5m) long monster weighing six tonnes.
A machine operator at the Suncor Millennium oil sand mine in northern Alberta stumbled on the fossil in 2011.
Experts from the Royal Tyrrell Museum took more than five years to remove the surrounding rock and reveal one of the best preserved dinosaur specimens ever uncovered.
The creature, from a family of armoured beasts known as “nodosaurs”, was named after museum technician Mark Mitchell, who spent more than 7,000 hours on the painstaking work.
Dr Brown said: “This nodosaur is truly remarkable in that it is completely covered in preserved scaly skin, yet is also preserved in three dimensions, retaining the original shape of the animal.
“The result is that the animal looks almost the same today as it did back in the Early Cretaceous. You don’t need to use much imagination to reconstruct it; if you just squint your eyes a bit, you could almost believe it was sleeping.
“It will go down in science history as one of the most beautiful and best preserved dinosaur specimens – the Mona Lisa of dinosaurs.”
The scientists, whose latest findings appear in the journal Current Biology, believe Borealopelta was washed out to sea after it died and mummified in mud.
The dinosaur, now on display at the Royal Tyrrell Museum, was covered in thick plate-like scales that formed fearsome spikes around its head and shoulders.
Its colouring was inferred by analysing organic compounds found in the scales.
The discovery of countershading was a surprise because of Borealopelta’s size and heavy protective armour. It suggests the threat from predators was high enough for natural selection to favour concealment, despite the animal’s natural defences.
On-going research is expected to produce more dramatic results.
The dinosaur was so well preserved the scientists even hope to find clues about its last meal by examining its stomach contents.