Ancient Mammal Tooth Marks in Prehistoric Animal Bones

Scientists have identified the tiny and faint scratch marks made by the teeth of ancient, primitive mammals as they gnawed on the remains of dinosaurs and other prehistoric animals. Evidence has been found of ancient mammal tooth marks in fossil bones.  In a paper published in the scientific journal “Paleontology”, the researchers from Yale University and the Cleveland Museum of Natural History report on the mammalian tooth marks left on the bones of several fossil bones, including the bones of dinosaurs.

Whilst studying the fossil collections at the University of Alberta Laboratory for Vertebrate Palaeontology at the Royal Tyrrell Museum (Drumheller, Alberta, Canada), Nicholas Longrich of Yale University and Michael J. Ryan of the Cleveland Museum discovered several of the bones showed signs of tooth marks.  Additional bones that seemed to have been gnawed upon were found during fieldwork in Alberta.  All the bones studied date from 75 million years ago (Campanian faunal stage of the Late Cretaceous).

The team discovered tooth marks on a femur bone (thigh bone) from a Champsosaurus, a crocodile-like, aquatic reptile that grew up to 1.5 metres long, the rib of a dinosaur, most likely a herbivorous hadrosaurid or ceratopsid; the femur of another large dinosaur that was likely another ornithischian and a lower jaw bone from a small marsupial.

The researchers believe the marks were made by mammals because they were created by opposing pairs of teeth—a trait seen only in mammals from that time.  They think they were most likely made by Multituberculates, an extinct order of archaic mammals that resemble rodents and had paired upper and lower incisors.  Several of the bones display multiple, overlapping bites made along the curve of the bone, revealing a pattern similar to the way people eat corn on the cob.

Ancient Mammal Tooth Marks

Pictures show parallel groves cut into the rib bone of a dinosaur, evidence of a mammal gnawing on bones preserved for 75 million years.

The Multituberculates are a mammalian subclass that first appeared in the Middle Jurassic and went extinct in the Eocene.  These mammals were relatively abundant in the northern hemisphere during the Late Cretaceous, probably herbivorous; many scientists believe that these creatures were mainly nocturnal.  Many Multituberculates resembled rodents although they were not closely related to modern placental mammals.

Diagrams show the typical skull of a Multituberculate mammal, showing that the tell-tale tooth marks found in the bone were probably made by the incisors as the grawed on the bone, not to strip meat but perhaps to gain important minerals and vitamins.  It was these unobtrusive animals that were to outlast the dinosaurs, as the Multituberculates survived into the Cenozoic.

Commenting on the tooth marks, the team conclude that the animals that left evidence of gnawed bones in the mega faunal fossil record of Alberta were probably no bigger than a squirrel.

Nicholas Longrich stated:

“The bones were kind of a nutritional supplement for these animals.”

He went onto add that there were probably a lot more fossils in museum collections and awating discovery that would show this behavioural evidence of primitive mammals.

“The marks stood out for me because I remember seeing the gnaw marks on the antlers of a deer my father brought home when I was young,  So when I saw it in the fossils, it was something I paid attention to.”

But he points out that the Late Cretaceous creatures that chewed on these bones were not nearly as adept at gnawing as today’s rodents, which developed that ability long after dinosaurs went extinct.

For models of prehistoric mammals: Prehistoric Mammal Replicas and Figures.

Theropod Dinosaurs –  A Range of Biting Styles

Bristol University researchers examine dinosaur biting techniques.  A subject area for the eager students to get their teeth into.

A new study into the biting styles and the forces that could be generated as a dinosaur bit into its prey has been published in the scientific journal “The Proceedings of the Royal Society – Biology”.  This study carried out by researchers at the University of Bristol, identifies at least four different biting techniques, it seems some dinosaurs were fast “nippers” whilst others had slower but more powerful bites.

The study focused on the bites of theropod dinosaurs.  Theropods (Theropoda) were bipedal and mostly meat-eating although a number of forms evolved to exploit different environmental niches resulting in a non-carnivorous diet in some cases.  The research shows that following a careful analysis of tooth position, tooth size, length of the jaws and the shape and design of theropod dinosaur skulls, four basic biting techniques were identified with a trade-off between bite strength and the speed of the bite.

Dinosaur Biting Techniques

The study indicates that meat-eating dinosaurs ranged from weak biters but fast biters such as the dromaeosaurs (Velociraptor, Deinonychus etc.) and the strong, more efficient biters such as the last of the tyrannosaurs (Tyrannosaurus rex).

The author of this new research, Manabu Sakamoto, a scientist in the Department of Earth Sciences at the University of Bristol (England), examined the biting characteristics of 41 different theropod dinosaurs, from Triassic, fleet-footed meat-eaters such as Coelophysis to the mighty allosaurs and tyrannosaurs.

Not surprisingly, the study shows that tyrannosaurs and allosaurs inflicted the most damaging, efficient bites.  These large predators probably relied on an swift ambush attack, then withdrawing to let their victim weaken through shock and blood-loss.  Tyrannosaurus rex had one of the best developed senses of smell known to science.  It could have used this superb sense of smell to track down its victim, even though the hapless animal may have wandered many miles from the scene of the attack.

The ceratosaurs, are also revealed as being efficient strong, biters.  Again, this is not surprising, as dinosaurs from the  Ceratosaurus genus (Ceratosaurus sp.) have some of the largest teeth in proportion to the size and width of the jaws in the reptilian fossil record.  Their dagger-like teeth seem almost too big for their own mouths.  One Ceratosaurus species Ceratosaurus ingens is only known from fossils of huge teeth that have been found.  The teeth indicate that this particular species of ceratosaurid may have been one of the biggest carnivores around during the Late Jurassic.

Ceratosaurus – Big Teeth = Fearsome Bite

Picture credit: Everything Dinosaur

The picture above shows a scale drawing of a typical ceratosaurid.

Interestingly, the oviraptorids come out very favourably in terms of the efficiency of their bites in this new study.  Oviraptorids were very bird-like dinosaurs, not only in their general build but also as a result of the presence of a beak.  Some scientists have suggested that this particular family of dinosaurs should not be classified as Dinosauria but as members of the Aves (birds).

Illustration of a Typical Oviraptorid

The head of Oviraptor.

Picture credit: Mike Fredericks

Everything Dinosaur stocks a wide range of theropod dinosaur figures and replicas: Theropod Dinosaur Models.

Studying Oviraptorids

Scientists are uncertain as to what sort of food oviraptorids ate.  The jaws seem to have evolved for a crushing action, perhaps these Cretaceous animals fed on nuts or hard fruit.  It has even been suggested that oviraptorids fed on shell fish, their strong jaws would have easily cracked open clams and the shells of other molluscs.

The research from the Bristol team shows that even though some dinosaurs did not have as many teeth as others, the teeth they did possess did a very efficient job.

Manabu Sakamoto commented on the efficiency on the bites of allosaurs and tyrannosaurs, he stated:

“These dinosaurs have consistently high efficiency in biting along the entirety of their relatively short tooth rows.”

The bite strength of the theropod dinosaurs studied was calculated by determining the ratio between the size of the muscles in the jaws and the biting force they could potentially generate.  This is termed “the mechanical advantage” and unlike previous studies into dinosaur bite forces, the Bristol University researchers calculated the bite strength for each tooth and biting position in the jaws.

Sakamoto discovered that the most primitive type of biting belonged to dinosaurs such as Herrerasaurus, Carcharodontosaurus, and Ceratosaurus.  Their back teeth did much of the work.

One of the most bizarre biting styles belonged to the coelophysoid dinosaurs, animals such as Coelophysis and Syntarsus.  These fast running, relatively small, meat-eaters were widespread during the Late Triassic and Early Jurassic.  Typically, they had long necks and small skulls with narrow jaws.  Coelophysids could bite with a great deal of force at the back of their mouths, but their front teeth were limited to a really weak and fast bite.  These particular dinosaurs probably preyed on smaller, fast moving prey such as lizards and other dinosaurs, but their long necks and narrow muzzles may have permitted them to scavenge the kills from larger meat-eaters.

The final type of carnivorous dino bite belonged to what Sakamoto called “the ostrich-like dinosaurs,” such as Velociraptor (dromaeosaurs).  Typically, these dinosaurs had more teeth in their jaws when compared to the larger allosaurs and tyrannosaurs.

Manabu commented on the findings:

“These dinosaurs have consistently low efficient biting across their tooth rows so they have relatively weak bites.  But, in effect, this also means that they have relatively fast biting speeds.”

He added that the research into the bite force and technique of Archaeopteryx (A. lithographica), showed that this ancient bird bit in a similar style to the Velociraptors.

Various Biting Styles

Another component of the study involved testing whether or not closely related dinosaurs bit in similar ways.  For the most part, this was true, providing evidence that the various biting styles were inherited, evolved behaviours.

However, there were one or two exceptions to this rule thrown up by the study.  The parrot-like oviraptorids and the therizinosaurs (Scythe Lizards), a bizarre type of theropod dinosaur that adapted to a vegetarian diet and are believed to have filled a “sloth-like” niche in Northern Hemisphere ecosystems; did not have predictable biting styles based on their evolutionary history.  Although, relatives of these two groups of dinosaurs were weak, yet fast biters, the oviraptosaurids and the therizinosaurids were highly efficient, strong biters.

Commenting on this aspect of the research Manabu suggested:

“A possible explanation is that the ancestral stock of this group underwent adaptive evolution and filled an open ecological and functional niche.”

Coahuilaceratops magnacuerna – The First Horned Dinosaur from Mexico

No sooner do we write an article about the discovery of a new genus of ceratopsian (horned dinosaur) from the western United States (Medusaceratops lokii), then the University of Utah, publishes a press release about a new genus of horned dinosaur, the first to be discovered in Mexico.

To read more about Medusaceratops lokii: Mystery Horned Dinosaur from Montana.

Unlike M. lokii, there is no doubting from the fossil remains that this particular ceratopsian is a chasmosaurine, the huge brow horns are a dead give away, and although the scientists admit they have yet to find an entire horn they estimate that the brow horns on C. magnacuerna are some of the biggest known in the fossil record.

New Genus of Horned Dinosaur

This discovery has given scientists fresh insights into the ancient history of western North America, according to a research team led by palaeontologists from the Utah Museum of Natural History at the University of Utah.

“We know very little about the dinosaurs of Mexico, and this find increases immeasurably our knowledge of the dinosaurs living in Mexico during the Late Cretaceous.”

Commented Mark Loewen, a palaeontologist with the museum and lead author of the study.

The 72-million-year-old rhino-sized creature – Coahuilaceratops magnacuerna – would have weighed perhaps as much as 4 tonnes.  The fossils date from the (Maastrichtian faunal stage of the Late Cretaceous).   The name Coahuilaceratops magnacuerna (pronounced Koh-WHE-lah-SARA-tops mag-NAH-KWER-na), refers to the Mexican state of Coahuila where it was found, and to the Greek word “ceratops” meaning “horned face.”  The second part of the name, or the specific name, magnacuerna, is a combination of Latin and Spanish meaning “great horn,” in reference to the huge horns above the eyes of this dinosaur (the brow horns).

An Illustration of Coahuilaceratops magnacuerna

Picture credit: Lukas Panzarin/Utah Museum of Natural History, the University of Utah.

The illustration above shows an artist’s interpretation of the ceratopsian skull material.  The huge and strongly re-curved brow horns are depicted.

The study, partially funded by the National Geographic Society, was conducted by Mark Loewen, Scott Sampson, Eric Lund and Mike Getty, palaeontologists at the Utah Museum of Natural History.  Also involved were Andrew Farke of the Raymond M. Alf Museum in Claremont, California.; Martha Aguillón-Martínez, Claudio de Leon and Rubén Rodríguez-de la Rosa from the Museum of the Desert in Saltillo, Mexico; and David Eberth of the Royal Tyrrell Museum of Palaeontology in Alberta, Canada.

Coahuilaceratops magnacuerna

The new species is to be announced in the book “New Perspectives on Horned Dinosaurs” to be released next week by Indiana University Press.  The lead author for this publication is Dr Michael J. Ryan and the book will contain more information on the new Montana Ceratopsian M. lokii.

For most of the Late Cretaceous Period, from 97 million to 65 million years ago, high global sea levels resulted in flooding of the central, low-lying portion of North America. As a result, a warm, shallow sea extended from the Gulf of Mexico to the Arctic Ocean, splitting the continent into eastern and western landmasses.  This sea is known as the Western Interior Seaway.

The Fossil skull of this Dinosaur

Coahuilaceratops Illustration.

Picture credit: Utah Museum of Natural History, the University of Utah

Dinosaurs living on the narrow, peninsula-like western landmass – known as Laramidia – occupied only a narrow belt of plains that were sandwiched between the seaway to the east and rising mountains to the west.  Central America had not formed at the time, which made Mexico the southern tip of this island continent.

Late Cretaceous Dinosaurs

In many ways, the Late Cretaceous is the best-understood time during the Age of Dinosaurs, thanks in large part to more than 120 years of dinosaur hunting in Canada, Montana, New Mexico and the Dakotas.  Recent work has revealed new dinosaurs living at the same time in Utah, New Mexico and Texas, yet the dinosaurs from Mexico have remained virtually unknown.

Scott Sampson commented:

“As the southernmost dinosaurs on Laramidia, Mexican dinosaurs will be a critical element in unravelling the ancient mystery of this island continent.”

Loewen described the arid, desert terrain where the dinosaur was recovered as nothing like Mexico during the Late Cretaceous.  About 72 million years ago, the region was a humid estuary with lush vegetation, an area where salt water from the ocean mixed with fresh water from rivers, much like the modern Gulf Coast of the southeastern United States (ruptured oil pipelines not permitting).  Many dinosaur bones in the area are covered with fossilised snails and marine clams, indicating that the dinosaurs inhabited environments adjacent to the seashore.

The Fossil Material Superimposed on a Line Drawing of the Skull

Fearsome Ceratopsian.

Picture credit: Utah Museum of Natural History, the University of Utah

The neck crest is assumed to be fenestrated (exhibiting holes in the bone, that in life would have been covered by skin).  A pair of fenestra are believed to be present, these would have helped lighten the neck crest and the skin patches could have been flushed with blood to make vivid display patterns, perhaps a part of chasmosaurine courtship.

The rocks in which Coahuilaceratops was found also contain large fossil deposits of jumbled duck-bill dinosaur skeletons.  These sites appear to represent mass death events, perhaps associated with storms such as hurricanes that occur in the region today.

Scott Sampson went on to add:

“Sitting near the southern tip of Laramidia, this region may have been hammered by monstrous storms.  If so, such periodic cataclysms likely devastated miles of coastline, killing off large numbers of dinosaurs.”

Until recent years, there have been few large-scale palaeontological projects in Mexico focused on the Mesozoic Era.  Indeed Coahuilaceratops is among the first dinosaurs from Mexico to be named.

Coahuilaceratops comes from a rock unit known as the Cerro del Pueblo Formation, which dates to between 71.5 million and 72.5 million years ago.  The skeletons, which de Leon discovered in 2001 near the town of Porvenir de Jalpa, approximately 40 miles west of Saltillo, were excavated in 2003.  The fossils then were prepared at the Utah Museum of Natural History, requiring two years of meticulous work by skilled volunteer preparator Jerry Golden.

Based on the bone development of the skull and skeleton, the scientists believe that this animal was an adult at the time of death.  Remains of a juvenile animal of the same species were also found at the site.

Coahuilaceratops was about 7 metres long as an adult, more than 2 metres high at the shoulder and hips, with a 1.8 metre long skull, it would have weighed more than an adult male Indian elephant.

By far the most obvious characteristic of Coahuilaceratops is its massive pair of horns, one above each eye.  While the researchers lack a complete horn, they estimate from fossils they excavated that the horns were more than one metre in length.

Although such horns are common features of ceratopsian dinosaurs, those of Coahuilaceratops appear to be the largest known for the group, exceeding the size of eye horns even in Triceratops horridus.  Scientists are uncertain of the massive eye horns’ purpose, but the most widely accepted idea is that they were related to reproductive success, functioning to attract mates and fight with rivals of the same species, although they would have acted as a substantial deterrent against hungry tyrannosaurs.

Mark Loewen explained that Coahuilaceratops represents the first occurrence of an identifiable species of horned dinosaur in southern Mexico.

He added:

“The horned dinosaurs are an extraordinary example of vertebrate evolution.  They evolved and diversified on Laramidia along a thin strip of land that stretched from Alaska to Mexico. Finding this horned dinosaur so far south in Mexico offers us a different picture of what the ancestors of Triceratops were like.”

In addition to Coahuilaceratops, the research team found remains of two other horned dinosaurs, which are less well understood.  The researchers are hoping to find more fossil material so that they can gain more information on these two other types of ceratopsian.

Other Dinosaurs Found

The latest expedition also recovered remains of two duck-bill dinosaurs, as well as the remains of carnivores, including large tyrannosaurs (smaller, older relatives of T. rex) and more diminutive Velociraptor-like predators armed with sickle-claws on their feet (dromaeosaurs).

Together with an abundance of fossilised bones, researchers discovered the largest assemblage of dinosaur trackways known from Mexico, an extensive area criss-crossed with the tracks of different kinds of dinosaurs.  In all, the emerging picture shows a diverse group of dinosaurian herbivores and carnivores, perhaps representing a previously unknown assemblage of species.

Commenting on the rich and diverse fossil material Mark Loewen stated:

“Rather than focusing only on individual varieties of dinosaurs, we are attempting to reveal what life was like in Mexico 72 million years ago, and understand how the unique ecosystem of Mexico relates to ecosystems to the north at the time.”

Few North American dinosaurs from this time period are known outside of the Drumheller region of Alberta. David Eberth explained that researchers now have two points of comparison to examine not only different dinosaurs, but also different environments and ecologies.

As might be suspected, paleontologists are excited about the future palaeontological potential of this area, they are confident that more dinosaur discoveries will be made.

Don Brinkman, a researcher at the Royal Tyrrell Museum (Drumheller, Alberta) added:

“Dinosaurs from this particular period are important because this is a time that is relatively poorly understood.”

Don is studying non-dinosaur vertebrates found at the site, including turtles, fish, and lizards.

He went onto state:

“The locality in Mexico goes a long way to filling in a gap in our knowledge of the record of changes in dinosaur assemblages throughout the Late Cretaceous.”

New Genus of Horned Dinosaur

Everything Dinosaur stocks a wide range of models and figures of Late Cretaceous ceratopsians.  For example, the UK-based company stocks the Beasts of the Mesozoic articulated model range: Beasts of the Mesozoic Models.

Everything Dinosaur acknowledges the assistance of a press release from the University of Utah in the compilation of this article.

Huge Chasmosaurine Medusaceratops lokii a Montana Dinosaur Mystery

Scientists at the Cleveland Museum of Natural History have announced the discovery of a new genus of horned dinosaur (Ceratopsian) from Late Cretaceous sediments in Montana.  This new dinosaur, that roamed this part of the United States in herds, approximately 78 million years ago, is estimated to have exceeded 6 metres in length and weighed over 2 tonnes.  This new prehistoric animal, a member of the same group of horned dinosaurs (Chasmosaurine) as Pentaceratops and Triceratops, has been named Medusaceratops lokii, the genus name relating to the flamboyant crest with numerous epoccipitals (lumps, bumps, and horns around the head crest), resembling the fearsome snake covered head of Medusa from Greek legend.  The species name is in deference to the Norse God of mischief – Loki, as when fossils of this dinosaur were first discovered it confused scientists as to whether is was a member of the chamosaurine or centrosaurines (two sub-groups of ceratopsians).

A Model of the Newly Described Dinosaur Medusaceratops

Named after the Greek Gorgon Medusa who had snakes for hair. A CollectA Medusaceratops dinosaur model.

The image (above) shows a replica from the CollectA Prehistoric Life model range: CollectA Age of Dinosaurs Prehistoric Life Models.

Horned Dinosaur

The announcement was made by the distinguished scientist and dinosaur expert Dr Michael J Ryan, who is based at the Cleveland Museum of Natural History (Ohio,United States).  The fossils of this new ornithischian ceratopsid have been dated to the Campanian faunal stage of the Cretaceous.

Dr Ryan, the curator and head of Vertebrate Palaeontology at the Cleveland museum has published his findings as lead author of a new book on North American horned dinosaurs; “New Perspectives on Horned Dinosaurs:  The Royal Tyrrell Museum Ceratopsian Symposium”.

We at Everything Dinosaur, have had the pleasure of reading a number of DrcRyan’s publications, as we sit here checking this article, a copy of “Dinosaur Provincial Park”, a volume on the ancient ecosystem of Alberta, Canada, is on a shelf in front of us.  DrcRyan was a contributor to this publication and many of the chapters written about Dinosauria contain references to his published work.

Medusaceratops belongs to the Chasmosaurinae subfamily of the horned dinosaur family Ceratopsidae.  The other subfamily is Centrosaurinae.  The specimen is the first Campanian-aged chasmosaurine ceratopsian found in Montana.  It is also the oldest known chasmosaurine ceratopsian known to science

Fossils of Medusaceratops were discovered in a bonebed on private land adjacent to the Milk river in north, central Montana.  Fossils and other material was acquired by Canada Fossil Inc. (Calgary, Alberta) in mid 1990s.  The company consulted Dr Ryan and his colleagues about the fossils, but at first the scientists were unable to make a positive identification.

Medusaceratops had giant brow bones more than 3 feet long over each eye, and a large, shield-like frill off the back of its skull adorned with large curling hooks.  Medusaceratops lokii means “Loki’s horned-faced Medusa,” referring to the thickened, fossilised, snake-like hooks on the side of the frill (the epoccipitals).

Commenting on this discovery, Dr Ryan stated:

“At first we could not figure out what we had.  Some of the material looked as if it came from a form related to Centrosaurus [centrosaurine ceratopsian, like Pachyrhinosaurus or Achelousaurus] a centrosaurine noted for having short brow horns.  The rest of the pieces had giant brow horns similar to Triceratops [Chasmosaurine].  That’s one of the problems with bonebeds – even though you can collect a large amount of material, much of it is broken and all of it is disarticulated, so the story is rarely clear cut.”

Eventually Dr Ryan found a complete articulated skull of a centrosaur with long brow horns in southern Alberta of what appeared to be the new animal from Montana, and named it Albertaceratops in 2007.  At that time, he assumed he was looking at a stray that had literally crossed the international border between what was to become Canada and the United States.

To read an article on the discovery of Albertaceratops: “Alberta Horned Face” – An Ancestor of Triceratops.

Medusaceratops lokii

After re-examining the material from Montana, Dr Ryan realised that at least some of the material in the Montana bonebed was not Albertaceratops.  Some of the elements were much larger than any other horned dinosaur from the same time period, including Albertaceratops.  Even though Albertaceratops and Medusaceratops are superficially very similar, the shape and number of the hooks and ornaments along the edge of the frill actually puts them in separate horned dinosaur groups, with Medusaceratops being a chasmosaur and Albertaceratops a centrosaurine.

Commenting on the huge frill on Medusaceratops, Dr Anthony Russell, Professor of Biological Sciences at the University of Calgary (Alberta) stated:

“Although the ornamentation on the frill is pretty spectacular, it probably was not used for defence against predators, rather it was more likely prehistoric “bling” used to attract a mate.”

The descriptive terms, used to distinguish centrosaurines from chasmosaurines are often not adequate to permit a genus to be ascribed to the appropriate subfamily of ceratopsians.  For example, the centrosaurines are often referred to as “short-frilled” dinosaurs, with large nose horns, often bigger than any brow horns, if brow horns were present.  In contrast, the chasmosaurines are known as “long-frilled” dinosaurs with large, neck frills and long snouts.  The brow horns are usually much bigger than any nose horn, if a nose horn was present.

An Illustration of Medusaceratops

An illustration of Medusaceratops. Picture credit: Caldey.

Dr Ryan said:

“Medusaceratops is the oldest member of the Chasmosaurinae in North America and shows that the group, like its most famous member, Triceratops, had long brow horns and were fairly large when they first evolved.  Later chasmosaurs that are just a bit younger [found in later strata], tend to have much shorter horns and have much lighter, smaller bodies.”

If this large, herbivore evolved large brow horns to fend off the attacks from predatory dinosaurs, then this poses an intriguing question for the scientists.  What types of really big predatory dinosaurs shared this environment with Medusaceratops?

A number of tyrannosaurid genera are known from the western part of North America (Campanian faunal stage), perhaps awaiting discovery are the fossils of a large carnivore bigger than Daspletosaurus or Gorgosaurus.

Dr Ryan said:

“Here we have something almost the size of Triceratops, but 10 million years before it lived.  T. rex was not around yet, so what was Medusaceratops squaring off against?  That’s one of the things we’re looking for in Alberta.”

The research was originally conducted when Michael Ryan was a Ph.D. candidate working with Dr Russell at the University of Calgary in Alberta, Canada.  Much of the material, including the holotype, is now in the collection of the Wyoming Dinosaur Centre in Thermopolis, Wyoming (USA), with other material curated at the Royal Tyrrell Museum in Drumheller, Alberta (Canada).