Dinosaur unearthed in Fort McMurray oilsands was carried to watery grave by 'bloat and float'

A dinosaur famously unearthed from a Fort McMurray oilsands mine was likely the victim of "bloat and float," says Edmonton paleontologist Scott Persons.

The Borealopeltaankylosaur skeleton was found at the Suncor site in 2011, tens of millions of years after it had been "dumped at sea."

"It had sunk to the bottom and settled down into the very fine silty sediment of the sea floor, before scavengers could disturb it and before the skeleton fell apart," Persons said during hisdinosaur series with CBC Edmonton's Radio Active.

"Bad stuff usually happened to their bodies. They got torn apart by scavengers, or their carcasses rotted and their skeletons fell apart into a big jumble.

"But not the Borealopelta specimen."

• World's best-preserved armoured dinosaur revealed in all its bumpy glory

Much like the opening scene of a murder mystery: a few hard-working labourers were going routinely about their jobs at the remote mine, when they stumbled across the specimen.

A team of expert detectives is called in to investigate, and a slew of mysterious circumstancessurface.

The fossil, which is now the centrepiece of a recently opened exhibit at the Royal Tyrrell Museum near Drumheller, is part of a larger paleontological mystery, said Persons, a PhDstudent atthe University of Alberta.

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The armoured herbivores, not much larger than the modern hippo, were land animalsbut their fossils are most often found in areas that were once submerged in prehistoric ocean.

How did the "Suncor Ankylosaur" reach its watery grave? Paleontologists believe they have cracked the case.

The dinosaur likely died in an inland marsh, and as it began to rot, its distended body was carried out to sea, Persons said.

"Bloat and float, that's something not uncommonly observed today, when the carcasses of cattle can be found bobbing up and down in the ocean," said Persons.

"Or when the corpse of an Indian elephant is seen floating down even a shallow portion of the Ganges River."

Persons hypothesizes that the dinosaur was living in the wetlands of prehistoric Alberta, it died of natural causes.

'Like really gross balloons'

"Imagine this, you are an elder Borealopelta living it up in the wetlands of prehistoric Alberta, but the time has come to shuffle off your mortal coil."

It died, but not in a violent way, said Persons.

"You aren't torn apart limb from limb by a hungry tyrannosaur or pack of raptors. You're done in by a disease, or a heart attack, or maybe you drank some bad swamp water," Persons said.

"As your body sits in the subtropical sun, you start to rot. Bacteria feeding on your soft insides produce gas as a byproduct."

You're done in by a disease, or a heart attack, or maybe you drank some bad swamp water.- Scott Persons, paleontologist

The ankylosaur, one of the best-preserved specimens of its kind, is the perfect example of this puzzling phenomenon, said Persons.

The combination of having extra big guts and heavy armour, which would bring the carcass quickly to the bottom of the briny deep, made ankylosaurs particularly prone to bloat and float.

From fossil records, paleontologists can tell that these armoured animals had great barrel-shaped bodies designed to house lots of digestive vats and looping intestines.

"As a big-gutted ankylosaur, you have lots of big digestive chambers that fill up with the rotting gasses quickly and swell, like really gross balloons.

"That's the bloat."

Listen toRadio Activewith hostPortia Clark, weekday afternoons at CBC Radio One, 93.9 FM in Edmonton. Follow the afternooncrew on Twitter@CBCRadioActive.