Name:
Borealopelta
(Northern shield).
Phonetic: Bor-e-al-pel-tah.
Named By: Caleb M. Brown, Donald M.
Henderson, Jakob Vinther, Ainara Sistiaga, Jorsua Herrera
& Roger E. Summons - 2017
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia, Nodosauridae.
Species: B. markmitchelli
(type).
Diet: Herbivore.
Size: Holotype individual estimated to be about
5.5 meters long.
Known locations: Canada, Alberta - Clearwater
Formation.
Time period: Albian of the Cretaceous.
Fossil representation: Skull and articulated partial
post cranial skeleton including armour. Holotype also preserves
keratinous heaths for armour, skin and stomach contents.
Melanosomes have also been identified in the skin.
The
level of preservation in the holotype individual of Borealopelta
is
exceptional to say the least. Somehow this land dwelling dinosaur
ended up in being preserved in marine sediment, possible
suggesting that this individual may have been washed out to sea,
perhaps in some sort of flood or land slide. It is probable that
this individual dinosaur drowned. This individual dinosaur eventually
sank down to the sea floor ending up resting on its back. This
allowed the soft sediment of the sea floor to begin preserving the
top half of the dinosaur. This has allowed for not just bones and
armour plates which is what we usually get with dinosaurs, but some
softer tissues, skin, stomach contents and even melanosomes, the
colour pigments within the skin!
To
begin, Borealopelta was a nodosaurid
dinosaur, a
quadrupedal
dinosaur with heavy armour plates running down its back. As a
nodosaur, Borealopelta would have lacked the tail
club that would
have been present in its ankylosaur cousins. The bony plates
(technically known as osteoderms) would have had a softer keratinous
covering. Analysis of melanosomes shows that Borealopelta
likely had
a reddish brown colour to at least the top half (preserved area)
of its body. Borealopelta may have also had a
counter shaded
pattern that served as camouflage.
The
nodosaurs have usually been interpreted as being selective browsers of
low growing plants, and the stomach contents of Borealopelta
certainly support this long held theory. Most of the plant material
within the stomach of this individual Borealopelta
were of ferns, and
their level of digestion suggests that this individual Borealopelta
may
have died only a few hours after eating them. The level of growth of
these ferns seems to suggest that they would have been within their
active growing period when eaten, remarkably revealing that this
Borealopelta died during the early-mid-summer
months. Charcoal was
also found within the stomach leading researchers to suggest that this
Borealopelta had been feeding upon the fresh growth
of plants that had
begun growing in an area recently ravaged by a wild fire.
Further reading
- Supplemental Information: An Exceptionally Preserved
Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and
Cretaceous Predator-Prey Dynamics. - Current Biology. 27
(16): 2514–2521.e3. - Caleb M. Brown, Donald M.
Henderson, Jakob Vinther, Ainara Sistiaga, Jorsua Herrera
& Roger E. Summons - 2017.
- Supplemental Information: An Exceptionally Preserved
Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and
Cretaceous Predator-Prey Dynamics. - Current Biology. 27
(16): 2514–2521.e3 - Caleb M. Brown, Donald M.
Henderson, Jakob Vinther, Ainara Sistiaga, Jorsua Herrera
& Roger E. Summons - 2017.
- An exceptionally preserved armored dinosaur reveals the morphology
and allometry of osteoderms and their horny epidermal coverings. -
PeerJ. 5: e4066. - Caleb M. Brow - 2017.
- Dietary palaeoecology of an Early Cretaceous armoured dinosaur
(Ornithischia; Nodosauridae) based on floral analysis of stomach
contents. - Royal Society. 7 (6): 200305. - Caleb M.
Brown, David R. Greenwood, Jessica E. Kalyniuk, Dennis R.
Braman, Donald M. Henderson, Cathy L. Greenwood &
James F. Basinger - 2020.