Borealopelta
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''Borealopelta'' (meaning "Northern shield") is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
nodosaurid Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the s ...
ankylosaur Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful l ...
from the
Lower Cretaceous Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also * Nizhny {{Disambiguation ...
of what is today
Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...
,
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
. It contains a single species, ''B. markmitchelli'', named in 2017 by Caleb Brown and colleagues from a well-preserved specimen known as the ''Suncor nodosaur''. Discovered at an
oil sands Oil sands are a type of unconventional petroleum deposit. They are either loose sands, or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen (a dense and extremely viscous ...
mine north of
Fort McMurray Fort McMurray ( ) is an urban service area in the Regional Municipality of Wood Buffalo in Alberta, Canada. It is located in northeast Alberta, in the middle of the Athabasca oil sands, surrounded by boreal forest. It has played a significa ...
, Alberta, the specimen is remarkable for being among the best-preserved dinosaur fossils of its size ever found. It preserved not only the armor (''
osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of Extant taxon, extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, Temnospondyli, ...
'') in their life positions, but also remains of their
keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hoove ...
sheaths, overlying skin, and stomach contents from the animal's last meal.
Melanosomes A melanosome is an organelle found in animal cells and is the site for synthesis, storage and transport of melanin, the most common light-absorbing pigment found in the animal kingdom. Melanosomes are responsible for color and photoprotection ...
were also found that indicate the animal had a reddish pinkish skin tone.


Discovery and history

The
holotype specimen A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was Species description, formally described. It is either the single such physical example (or illus ...
was uncovered on March 21, 2011, at the Millennium Mine, an
oil sands Oil sands are a type of unconventional petroleum deposit. They are either loose sands, or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen (a dense and extremely viscous ...
mine north of
Fort McMurray Fort McMurray ( ) is an urban service area in the Regional Municipality of Wood Buffalo in Alberta, Canada. It is located in northeast Alberta, in the middle of the Athabasca oil sands, surrounded by boreal forest. It has played a significa ...
, Alberta, that is owned and operated by
Suncor Energy Suncor Energy Inc. () is a Canada, Canadian integrated energy company based in Calgary, Alberta. It specializes in production of synthetic crude from oil sands. In the 2020 Forbes Global 2000, Suncor Energy was ranked as the 48th-largest public ...
. It was discovered by a miner, Shawn Funk, who was digging in the bank and noticed the specimen. The Wabiskaw Member sediments (belonging to the
Clearwater Formation The Clearwater Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin in northeastern Alberta, Canada. It was first defined by R.G. McConnell in 1893 and takes its name from the Clearwater Riv ...
) were being removed to allow mining of the underlying
bitumen Bitumen ( , ) is an immensely viscosity, viscous constituent of petroleum. Depending on its exact composition, it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American Engl ...
-rich sands of the
McMurray Formation The McMurray Formation is a Stratigraphy, stratigraphic unit of Early Cretaceous Geochronology, age (late Barremian to Aptian stage) of the Western Canadian Sedimentary Basin, Western Canada Sedimentary Basin in northeastern Alberta. It takes the ...
when an excavator struck the fossil. Noting the unusual nature of the exposed fragments, the operators alerted the
Royal Tyrrell Museum of Palaeontology The Royal Tyrrell Museum of Palaeontology (RTMP; often referred to as the Royal Tyrrell Museum) is a palaeontology museum and research facility in Drumheller, Alberta, Canada. The museum was named in honour of Joseph Burr Tyrrell, and is situate ...
. In accordance with Suncor's mining permit and Alberta fossil law, the specimen became the property of the Alberta government. On March 23, Royal Tyrrell Museum scientist
Donald Henderson Donald Ainslie Henderson (September 7, 1928 – August 19, 2016) was an American physician, educator, and epidemiologist who directed a 10-year international effort (1967–1977) that eradicated smallpox throughout the world and launched int ...
and senior technician
Darren Tanke Darren H. Tanke (born 1960) is a Canadian fossil preparation technician of the Dinosaur Research Program at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta. Born in Calgary, Tanke became interested in natural history at an early ...
were brought to the mine to examine the specimen, which, based on photographs, they expected to be a
plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...
or another
marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including mari ...
, as no land animals had ever been discovered in the oil sands previously. Upon correct identification, which was made on-site by Tanke, Henderson was astonished to learn that it was an
ankylosaurian Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. ...
dinosaur and not a marine reptile. The animal had apparently been washed out to sea after death. After three days of mine safety training, museum staff and Suncor employees began working to recover all pieces of the fossil. Aside from the several pieces broken free, the bulk of the specimen was still embedded up a cliff that was high. The process took fourteen days in total. As the major piece of rock containing the fossil was being lifted out, it broke under its own weight into several pieces. Museum staff salvaged the specimen by wrapping and stabilizing the pieces in plaster, after which they were able to successfully transport them to the Royal Tyrell Museum. There, technician Mark Mitchell spent six years removing the adhering rock and preparing the fossil for study, which was sponsored by the
National Geographic Society The National Geographic Society, headquartered in Washington, D.C., United States, is one of the largest nonprofit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, natural sc ...
. The species ''B. markmitchelli'' was named for him in recognition of his skilled work. The specimen was put on public exhibit on May 12, 2017, as part of the Royal Tyrrell Museum's "Grounds for Discovery" exhibition, along with other specimens discovered via industrial activity.


Description

''Borealopelta'' was a large dinosaur, measuring long and weighing . The Suncor specimen is remarkable for its three-dimensional preservation of a large, articulated dinosaur complete with soft tissue. While many small dinosaurs have been preserved with traces of soft tissues and skin, they are usually flattened and compressed during
fossilization A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
. Similar-looking
hadrosaurid Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...
"mummies" have a shriveled, desiccated appearance, due to their partial
mummification A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay furt ...
prior to fossilization. The Suncor specimen, however, appears to have sunk upside-down onto the sea floor shortly after its death, causing the top half of the body to be quickly buried with minimal distortion. The result is a specimen that preserves the animal almost as it would have looked in life, without flattening or shriveling. The Suncor specimen preserved numerous closely spaced rows of small armor plates, or osteoderms, lining the top and sides of its broad body. It had a straight tail rather than a tail club unlike any ankylosaurids, and from the shoulders protruded a pair of long spines, shaped like the horns of a bull. Study of the pigments present in remnants of skin and scales suggest that it might have had a reddish-brown coloration in life, with a countershaded pattern that was used for camouflage.


Classification

''Borealopelta'' was classified by Brown ''et al.'' within
Nodosauridae Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the ...
. In the
phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...
conducted by the authors, ''Borealopelta'' nested within nodosaurids more derived than ''
Nodosaurus ''Nodosaurus'' (meaning 'knobbed lizard') is a genus of herbivore, herbivorous nodosauridae, nodosaurid ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found exclusively in the Frontier Formation in Wyoming. Descripti ...
''. The completed
cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
was a strict consensus in 480 different trees, each with slightly different results. In both strict consensus and majority rules cladograms ''Borealopelta'' nested with ''
Pawpawsaurus ''Pawpawsaurus'', meaning "Pawpaw Lizard", is a nodosaurid ankylosaur from the Cretaceous (late Albian) of Tarrant County, Texas, discovered in May 1992. The only species yet assigned to this taxon, ''Pawpawsaurus campbelli,'' is based on a compl ...
'' and ''
Europelta ''Europelta'' (meaning “Europe’s shield”) is a monospecific genus of nodosauridae, nodosaurid dinosaur from Spain that lived during the Early Cretaceous (early Albian stage, ~113.0 Ma) in what is now the lower Escucha Formation of the Terue ...
'' in a group of Albian nodosaurs, with '' Hungarosaurus'' being the next closest taxon. The phylogeny below displays the results of the strict consensus, excluding taxa outside Nodosauridae.


Paleobiology

The discovery that ''Borealopelta'' possessed camouflage coloration, indicates that it was under threat of
predation Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...
, despite its large size, and that the armor on its back was primarily used for defensive rather than display purposes. Additionally, the spikes of ''Borealopelta'' might have had a dual function as defensive weapons and potential display structures useful in attracting mates and in species recognition.


Diet

Examination of the specimen's stomach contents indicates that ferns were a major part of the animal's diet. The fact that ferns made up the majority of ''Borealopelta's'' last meal suggested that it was a highly selective feeder. Roughly six percent of the stomach contents contained charcoal as well, leading to the conclusion that ''Borealopelta'' was feeding in an area that was experiencing regrowth after a recent wildfire. Brown and colleagues inferred that the ferns themselves had been halfway through their growing season when ingested, suggesting that the ''Borealopelta'' individual ingested them in early or mid-summer, dying only a few hours afterward. In 2023, Kalyniuk and colleagues compared the flora of the Gates Formation to the stomach contents of ''Borealopelta'' and suggested that type specimen fed on ferns selectively or in a fern-rich area that was recently disturbed.


Paleoecology

The Suncor ''Borealopelta'' was preserved in the marine
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s and
shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...
s of the Wabiskaw Member of the
Clearwater Formation The Clearwater Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin in northeastern Alberta, Canada. It was first defined by R.G. McConnell in 1893 and takes its name from the Clearwater Riv ...
, which were laid down during the Albian stage of the
Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
period, about 110–112 million years ago. At that time, the region was covered by the
Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...
, an inland sea that stretched from the
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...
to the
Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
, and the Wabiskaw sediments were being deposited in an offshore marine environment. The
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
specimen of ''Borealopelta'' must have been washed out to sea, perhaps during a flood. Initially, it was thought that it had bloated after death and floated on its back at the surface of the water for weeks before the eventual release of the built-up gases within the trunk region of the carcass at which point it sank. Larramendi and colleagues in 2020 doubted this hypothesis, as ankylosaurians would need a density comparable to modern birds for this to occur which is most certainly not the case; instead, it is thought that the animal was washed out to sea where it drowned after struggling to stay near the surface and then proceeded to sink. The fact that ankylosaurians are front-heavy is probably what led to the animal being fossilized upside down. It landed on the seabed on its back with enough force to deform the immediately underlying sediments. About of sediment settled over the carcass prior to the release of body fluids, as evidenced by fluid-escape structures preserved in the sediments, and the body cavity became filled with sand. A
siderite Siderite is a mineral composed of iron(II) carbonate (FeCO3). Its name comes from the Ancient Greek word (), meaning "iron". A valuable iron ore, it consists of 48% iron and lacks sulfur and phosphorus. Zinc, magnesium, and manganese commonly ...
concretion A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...
began to form around the carcass shortly after its arrival on the seabed, which prevented scavenging and preserved the body intact, with its scales and
osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amph ...
s in their original configuration.


See also

*
Dinosaur coloration Dinosaur coloration is generally one of the unknowns in the field of paleontology, as skin pigmentation is nearly always lost during the fossilization process. However, recent studies of feathered dinosaurs and skin impressions have shown the c ...
*
Timeline of ankylosaur research This timeline of ankylosaur research is a chronological listing of events in the History of paleontology, history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spik ...
*
2017 in archosaur paleontology The year 2017 in archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontolo ...


References


External links

*
Adrift at sea in the Early Cretaceous – the Fort McMurray armoured dinosaur
(video) – Donald Henderson for Royal Tyrrell Museum Speaker Series, 2012 {{Portal bar, Dinosaurs, Canada Nodosauridae Dinosaur genera Albian dinosaurs Fossil taxa described in 2017 Dinosaurs of Canada