DinoDex
Armoured four-legged dinosaur with long shoulder spikes in side view
Life reconstruction of the nodosaur Borealopelta markmitchelli with its reddish-brown countershaded colouring.Image credit: Connor Ashbridge, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

Borealopelta markmitchelli

Pronounced bor-ee-AL-oh-PEL-tah mark-MICH-el-eye

Ankylosauria · Nodosauridae

A nodosaur from the Early Cretaceous of Alberta preserved in 3D with its skin, horn-covered armor, pigment and last meal. Found in an oil-sands mine in 2011, it had washed out to sea and was buried on the sea floor.

  • Armored
  • Quadrupedal
  • Exceptional preservation
  • Skin impressions known
  • Famous specimen
Compare
Period
Cretaceous· Albian
Diet
Herbivore
Length
5.5 m
Mass
1,300 kg
Location
Alberta, Canada

Quick answers

How big was Borealopelta markmitchelli?
Borealopelta markmitchelli was about 5.5 m long. It stood about 1.2–1.6 m tall at the hips. It weighed about 1.3 t. (Wikipedia: Borealopelta 2026; Paul 2016)
When did Borealopelta markmitchelli live?
Borealopelta markmitchelli lived during the Early Cretaceous, about 113–100.5 million years ago. (Brown et al. 2020; Cohen et al. 2023)
Where have Borealopelta markmitchelli fossils been found?
Fossils of Borealopelta markmitchelli have been found in Clearwater Formation (Alberta) and Canada. (Brown et al. 2017; Brown 2017)
What did Borealopelta markmitchelli eat?
Borealopelta markmitchelli was a herbivore. (Brown et al. 2017; Brown 2017)
Who named Borealopelta markmitchelli, and when?
Borealopelta markmitchelli was described by Caleb M. Brown et al. in 2017. (Brown et al. 2017; Brown 2017)

On this page

Period
Cretaceous113–100.5 Ma
Diet
Herbivore
Length
5.5 m
Mass
1.3 t
Location
Canada
Classification
Ankylosauria · Nodosauridae
Described
2017, Caleb M. Brown et al.

Overview

Borealopelta markmitchelli lived in what is now northern Alberta in the Early Cretaceous (early Albian). Its body floated out to sea and sank, and was buried in marine sediments of the Clearwater Formation. Shawn Funk found it in 2011 while digging at the Suncor Millennium Mine near Fort McMurray; technician Mark Mitchell spent nearly six years preparing it.

It is one of the best-preserved dinosaurs ever found: the front half of the body is in three dimensions, with the bony armor still capped by horn (keratin) sheaths and covered by scales. Melanin traces show it was darker on the back than on the belly, a camouflage pattern called countershading, which suggests that even a 1.3-tonne armored animal was hunted by large predators.

A mass in its belly holds its last meal: mostly fern leaves, with some twigs and about 6% charcoal. The plants point to feeding in late spring or summer, perhaps on regrowth after a wildfire (Brown et al. 2020).

Name meaning

"Northern shield", from Latin borealis ("northern") and Greek peltē ("shield"); markmitchelli honours Mark Mitchell, who prepared the specimen (Brown et al. 2017).

Biology & evidence

What scientists think about how this animal lived, and how strong the evidence for each idea is.

Feeding

  • Borealopelta fed on plants regrowing after a wildfire.

    Evidence level: Hypothesis

    About 6% of the meal is charcoal, which may mean it browsed ferns in a recently burned forest.

    Evidence for / against · 1
    Evidence for

    • Specimen · Borealopelta stomach contents

      A mass in the abdomen made of 88% leaf tissue, 85% of it leptosporangiate ferns, with stems, wood and about 6% charcoal.

      Specimen: TMP 2011.033.0001

  • The last meal of Borealopelta was mostly ferns.

    Evidence level: Direct evidence

    Plant remains preserved in its stomach are dominated by fern leaves, with few cycads or conifers. It is one meal, not a full diet.

    Evidence for / against · 1
    Evidence for

    • Specimen · Borealopelta stomach contents

      A mass in the abdomen made of 88% leaf tissue, 85% of it leptosporangiate ferns, with stems, wood and about 6% charcoal.

      Specimen: TMP 2011.033.0001

Skin & covering

  • Borealopelta was countershaded, darker above and lighter below.

    Evidence level: Moderate evidence

    Chemical traces of melanin show the pattern. Countershading is camouflage, which implies that large predators hunted even this armored animal.

    Evidence for / against · 1
    Evidence for

    • Other · Borealopelta melanin pattern

      Melanin identified by mass spectrometry in the organic residues, with a darker back and lighter underside, and paler parascapular spines.

      Specimen: TMP 2011.033.0001

  • The armor of Borealopelta was covered by horn sheaths and scales.

    Evidence level: Direct evidence

    The sheaths are preserved in place over the bony plates, which shows spines were longer in life than the bone alone suggests.

    Evidence for / against · 1
    Evidence for

    • Skin impression · Borealopelta keratin sheaths and scales

      Organic scales and horn-like keratin sheaths cap and exaggerate nearly all osteoderms along the body.

      Specimen: TMP 2011.033.0001

Location of the abdominal mass with preserved stomach contents in Borealopelta markmitchelli (Brown et al. 2020).Image credit: Caleb M. Brown, David R. Greenwood, Jessica E. Kalyniuk, Dennis R. Braman, Donald M. Henderson, Cathy L. Greenwood & James F. Basinger, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

Size

Length
5.5 m

(18 ft)

Based on TMP 2011.033.0001

Height
1.4 mpublished range 1.2–1.6 m

(4.6 ft)

Based on TMP 2011.033.0001

Mass
1,300 kg

Based on TMP 2011.033.0001

Borealopelta markmitchelli was about 5.5 m (18 ft) long, roughly 3.1 times the height of a 1.8 m adult human.

Timeline

Lived from about 113 to 100.5 million years ago (Ma), within the Mesozoic era (252–66 Ma).

Periods: Albian (113–100.5 Ma), Early Cretaceous (145–100.5 Ma)

Albian stage bounds; ammonite, pollen and foraminifera date the Wabiskaw Member to the Early Albian (Brown et al. 2020). PBDB still lists the occurrence as Aptian.

Location

Formations

Map data: Natural Earth (public domain). Modern positions, not where the continents were then.

These are the places where fossils have been found, not the full area where the animal lived.

Ecosystem

Lived in: Clearwater Sea

marine margin

An Early Cretaceous shallow sea (between fair- and storm-weather wave base) 200-400 km off the coast; Borealopelta is a land animal carried out to sea.

Classification

  1. cladeDinosauria
  2. cladeOrnithischia
  3. cladeThyreophora
  4. cladeAnkylosauria
  5. familyNodosauridae
  6. genusBorealopelta
  7. speciesBorealopelta markmitchelli

Taxonomic status: Valid

Fossil record

The Borealopelta markmitchelli holotype TMP 2011.033.0001, preserved in three dimensions with its armour in place, at the Royal Tyrrell Museum.Image credit: Etemenanki3, CC BY-SA 4.0, via Wikimedia Commons (unmodified except resizing), Royal Tyrrell Museum of PalaeontologyCC BY-SA 4.0 (unmodified)Source (opens in a new tab)
Specimens
Catalog numberStatusInstitutionFound
TMP 2011.033.0001HolotypeRoyal Tyrrell Museum of Palaeontology (TMP)2011

What has been found

Holotype: TMP 2011.033.0001

  • Preserved
  • Partial
  • Reconstructed
  • Unknown / not recorded
Region by region (table)
Skeleton regions of Holotype: TMP 2011.033.0001
RegionState
SkullPreserved
MandibleUnknown / not recorded
TeethUnknown / not recorded
Cervical vertebraePreserved
Dorsal vertebraePreserved
SacrumPartial
Caudal vertebraeUnknown / not recorded
RibsPreserved
GastraliaUnknown / not recorded
Scapula / shoulder girdleUnknown / not recorded
HumerusUnknown / not recorded
Forearm (radius / ulna)Unknown / not recorded
Hand (manus)Unknown / not recorded
PelvisUnknown / not recorded
FemurUnknown / not recorded
Tibia / fibulaUnknown / not recorded
Foot (pes)Unknown / not recorded
Dorsal view of TMP 2011.033.0001 showing the arrangement of osteoderms and scales (Brown et al. 2017); scale bar 1 m.Image credit: Caleb M. Brown, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

All specimens

Discovery

Year described
2017
Described by
Caleb M. Brown et al.
Type specimen
TMP 2011.033.0001

Discovery timeline

  1. 2011 · First material found

    Shawn Funk finds a nodosaur in an oil-sands mine

    A heavy-equipment operator hits the fossil at the Suncor Millennium Mine; the Royal Tyrrell Museum excavates it.

    People: Shawn Funk, Donald M. Henderson

  2. 2017 · Formally described

    Brown et al. name Borealopelta markmitchelli

    The new nodosaur is described with evidence of countershading.

    People: Caleb M. Brown, Donald M. Henderson

  3. 2020 · Major study

    The last meal of Borealopelta is described

    The stomach contents are analysed plant by plant.

    People: Caleb M. Brown

Sources

  1. (2026). Paleobiology Database: Borealopelta occurrences. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/occs/list.txt?base_name=Borealopelta&show=coords,paleoloc,strat,loc,ref&pgm=gplates (opens in a new tab)
  2. (2026). Wikipedia: Borealopelta. Wikipedia (English), accessed 2026-09-23. https://en.wikipedia.org/wiki/Borealopelta (opens in a new tab)
  3. Brown, C. M. (2017). An exceptionally preserved armored dinosaur reveals the morphology and allometry of osteoderms and their horny epidermal coverings. PeerJ 5: e4066. doi:10.7717/peerj.4066 (opens in a new tab)
  4. Brown, C. M., Greenwood, D. R., Kalyniuk, J. E., Braman, D. R., Henderson, D. M., Greenwood, C. L. & Basinger, J. F. (2020). Dietary palaeoecology of an Early Cretaceous armoured dinosaur (Ornithischia; Nodosauridae) based on floral analysis of stomach contents. Royal Society Open Science 7: 200305. doi:10.1098/rsos.200305 (opens in a new tab)
  5. Brown, C. M., Henderson, D. M., Vinther, J., Fletcher, I., Sistiaga, A., Herrera, J. & Summons, R. E. (2017). An exceptionally preserved three-dimensional armored dinosaur reveals insights into coloration and Cretaceous predator-prey dynamics. Current Biology 27: 2514-2521. doi:10.1016/j.cub.2017.06.071 (opens in a new tab)
  6. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf (opens in a new tab)
  7. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.