Last year, pictures of possibly the most well-preserved dinosaur ever found wowed the world. Now, a scientific description of this precious specimen has been published, giving surprising insight into its behavior. Despite having armor a rhinoceros would envy, even this mighty beast hid from the fearsome predators of the early Cretaceous.
When the exceptional fossil was announced last year, the public was told it was a 110-million-year-old nodosaur, which like other Ankylosauria were known for their heavy armor. However, as a previously unknown species and genus, the scientific description took longer. Now, the details of Borealopelta markmitchelli, as the creature has been named, have been published in Current Biology, along with some revealing insights into its lifestyle.
"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," said Dr Caleb Brown of the Royal Tyrrell Museum in a statement. "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 scales are so well preserved that palaeontologists were able to extract organic compounds from them and analyze these to establish the dinosaur’s coloring. This revealed a reddish brown pigmentation and countershading that would have helped it hide in shaded environments. Countershading is common among species small enough to be vulnerable to predators, but rare among mid-sized mammals and unknown today for adults weighing more than a tonne. B. markmitchelli was 5.5 meters (18 feet) long and weighed 1.3 tonnes (2,800 pounds).
Ambush predators may also find camouflage useful, but B. marchmitchelli was an herbivore. Instead, it must have lived in fear of therapod dinosaurs capable of biting through its bony armor.
Occasionally, however, B. marchmitchelli wanted to show off, perhaps to attract mates or warn rivals, as one of its spines was lighter colored, apparently to use in display.
Borealopelta means northern shield, reflecting the dinosaur’s location and armor. Mark Mitchell was honored in recognition of having spent more than 7,000 hours extracting the fossil from the rocks in which it was encased and preparing it for study. The superb preservation reflects the fact that even though B. markmitchelli lived on land, it was swept out to sea after death and quickly covered in sedimentary layers in a low-oxygen environment, preserving it from scavenging and rapidly turning the carcass to stone.