This month, the Royal Tyrrell Museum of Paleontology, near Drumheller, Alta., unveiled a new exhibit of fossils found at industrial sites.
The centrepiece is the nodosaur, a 110-million-year- old fossil unearthed from a Suncor mine in the oil sands. Donald Henderson, the museum's curator of dinosaurs, calls it the 'best-preserved armoured dinosaur in the world.'
When did you first know something special had been unearthed?
We knew at about the middle of April, 2011. Suncor's geology people had sent us some photos and everybody here looked at them and we thought, yeah, it is probably a plesiosaur or ichthyosaur, because we'd had them from the Syncrude mine occasionally over the previous 20 years.
So Suncor flew myself and technician Darren Tanke up about two days later. And once we were on site, we looked at the pieces and they certainly weren't working as a plesiosaur. And Tanke said, "What if it is a dinosaur?" And then it all made sense. It was such a surprise.
Where do you start? First off, it is three-dimensional. Most dinosaur fossils of any size are two-dimensional. But here we had an animal that was only very lightly squished. It is basically 3-D. We're famous for our dinosaurs in the southern half of the province but they are all from about 75 to 66 million [years ago]. This thing is 110, 112 million [years old]. So it is much older. It is probably the best-preserved armoured dinosaur in the world.
How did it stay so well preserved?
It is a land animal that was found buried at sea. So it went to the seabed on its back and that tells us that the carcass must have been really bloated – classic belly up. We describe it as bloat-and-float. So there's a shallow seaway through the interior of western North America. And just like today, there were major rivers coming out of the rising mountains to the west and we think our animal got swept out to sea.
So it was good it got swept out to sea, because then it wouldn't be scavenged by any terrestrial predators. It went far out to sea before it eventually went pop and sank. And it went to the seabed really quickly and was entombed in fine mud.
And also I think because the hide was so heavily armoured, that protected it from any marine scavengers. We know that there would have been big fish and big marine reptiles. And also I think the hide was so strong it kept the body together long enough to get it way offshore and out into deeper water.
How did the nodosaur spend its days?
It was a pretty big animal – about 5.5 metres long and 1.3 metric tonnes. It was really well armoured. It didn't have to worry about being eaten. And these things have really tiny brains. It was dumb. I think its day [involved] just calmly eating and digesting large quantities of vegetation. And the sense we get from finds elsewhere in the world – these were solitary animals. A lot of people have likened them to the rhino today, the white rhino in Africa – because they are pretty aggressive solitary animals most of the time. They are actually very rare.
The specimen has remarkable detail. What can you glean from it?
The armour is all in place. And most armoured dinosaurs, when they finally got buried, they were quite decayed. The skin had started to break down and all the connective tissue is gone and the armour slides away or gets sheared off by flowing water or scavengers pulling on it. But here everything was in place. We can see the direct correspondence between the ribs and the spine and the vertebrae and where the armour was. So developmentally you can see how there's an interaction between different earlier tissues and later tissues such as the armour and the skin.
We now know where a lot of the armour goes in these animals. Previously it was a bit of a guess. We can also see the true patterns and how the armour varies as you go from the middle of the body out to the outside and how it changes from the head-neck area as you go back across the body. And because it is so well preserved, I suspect future people will look at microscopic sections of the armour and see how it grew and developed, and when you do that same analysis over a range of these armoured dinosaurs, you can get a sense of how their development evolved.
This interview has been edited and condensed.