Borealopelta markmitchelli

Borealopelta markmitchelli was a nodosaurid ankylosaur entombed in marine sediments after its carcass drifted away from the Early Cretaceous Alberta coast. The front half of the body survives as a three-dimensional block with armor and skin close to their life positions. Chemical evidence indicates reddish-brown pigmentation and countershading, while preserved stomach contents reveal a last meal dominated by ferns. This extraordinary specimen provides a rare evidence-based view of the external appearance and diet of a large dinosaur.

Its fossils occur between approximately 112.6 and 110.5 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

Borealopelta had a broad, low body protected by tightly arranged osteoderms and keratin-covered spikes. Large paired spines projected from the shoulders, with smaller armor along the neck and back. Preserved soft tissues show the real contours around the neck and torso rather than only the underlying skeleton. Its broad beak and small teeth cropped low vegetation.

• Three-dimensionally preserved skin and body outline
• Armor retained near its life position
• Keratinous sheaths preserved over shoulder spines
• Reddish-brown dorsal pigmentation and countershading
• Broad beak for cropping low vegetation
• Stomach contents dominated by fern material

Heavy-equipment operator Shawn Funk exposed the specimen at Suncor's Millennium Mine north of Fort McMurray on 21 March 2011. Royal Tyrrell Museum crews recovered the block from the Clearwater Formation. Technician Mark Mitchell spent more than five years and roughly 7,000 hours preparing it. Caleb Brown and colleagues named Borealopelta markmitchelli in 2017, honouring Mitchell's work.

Discovery credit: Shawn Funk, Suncor Millennium Mine workers.

Naming authors: Caleb M. Brown, Donald M. Henderson, Jakob Vinther.

Borealopelta lived on humid coastal lowlands in northern Alberta. After death, the carcass entered the Western Interior Seaway, floated offshore, sank and was rapidly buried in oxygen-poor marine mud of the Clearwater Formation.

Its stomach contents show selective feeding on ferns shortly before death and include charcoal, perhaps swallowed while browsing recently burned vegetation. Countershading suggests that camouflage remained useful despite heavy armor. Social behaviour, mating displays and parental care are unknown.

• The fossil preserves armor, skin, horn coverings, stomach contents and evidence of body colour.
• Mark Mitchell spent roughly 7,000 hours preparing the specimen.
• It was discovered accidentally in an oil-sands mine.
• The animal's last meal consisted mostly of ferns.

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1. 01
   The Paleobiology Database

   Open source
2. 02
   An exceptionally preserved three-dimensional armored dinosaur reveals insights into coloration and Cretaceous predator-prey dynamics

   Caleb M. Brown, Donald M. Henderson, Jakob Vinther and 4 coauthors · Current Biology 27(16), 2514–2521.e3 · 2017

   Open source
3. 03
   Breakthroughs: Borealopelta markmitchelli

   Royal Tyrrell Museum of Palaeontology

   Open source