Its collision with the sediment down there created a small crater, which was then soon covered by a layer of mud that prevented any oxygen – or hungry bottom-feeders – from getting to it, which inhibited both chemical and physical decomposition. Increasingly compacted by the layers of sediment above, it began to mineralize rather than break down.
It became petrified, as if it had caught the gaze of Medusa herself.
To say this is an unprecedented find would be quite the understatement. Now on display at the Royal Tyrrell Museum of Paleontology in Alberta, it looks more like a statue than a real fossil. Although it’s now lacking in any distinct color, the chemicals trapped in its mineralized skin suggests it may have once been reddish in color.
“I feel like this is the most impressive fossil I have ever seen,” Franzi Sattler, a palaeontologist specializing in evolutionary biology and biodiversity from the Free University of Berlin who was not involved in the project, told IFLScience.
“As paleontologists we get to see all kinds of vertebrate and invertebrate fossils in various states of preservation. It is very common to even see bones in different colors,” Sattler added. “But this is not just bones, it is a view of a dinosaur as it would have been when it was alive.”
“I can only imagine how exciting it would be to work on this specimen. It's beautiful!”
Around 5.5 meters (18 feet) long and weighing at least 1.1 tonnes (2,500 pounds), this four-legged, rather stout dinosaur is setting all kinds of records aside from its immaculate preservation. It’s the oldest dinosaur that has been excavated in the region, and it belongs to not just its own species, but its own genus, a higher biological “class”.
Armored though it may be, this fossil was still somewhat fragile when it was first dug out of the oil sands of Alberta. It took a team led by the museum’s fossil preparator Mark Mitchell more than 7,000 hours over the past five years to fully expose the nodosaur’s skin, bones, and armor.
The story doesn’t end here, however. The team are still working on their official paper, and as part of their research, they’ll be scanning the petrified dinosaur to see what its internal organs looked like. In fact, because the mineralization of the skin happened so quickly, there’s a chance that some of its organs may still be partially intact.
Watch this space.