Dinosaur skull may reveal T. rex’s smaller cousin from the north

A 70 million year old fossil found in the Late Cretaceous sediments of Alaska reveals a new small tyrannosaur, according to a paper published in the open-access journal PLOS ONE on March 12, 2014 by co-authors Anthony Fiorillo and Ronald S. Tykoski from Perot Museum of Nature and Science, Texas, and colleagues.

Tyrannosaurs, the lineage of carnivorous theropod (“beast feet”) dinosaurs that include T. rex, have captivated our attention, but the majority of our knowledge about this group comes from fossils from low- to mid-latitudes of North America and Asia. In this study, scientists analyzed the partial skull roof, maxilla, and jaw, recovered from Prince Creek Formation in Northern Alaska, of a dinosaur originally believed to belong to a different species, and then compared the fossils to known tyrannosaurine species.

According to the results of the authors’ analysis, the cranial bones represent Nanuqsaurus hoglundi, a new tyrannosaurine species closely related to two other tyrannosaurides, Tarbosaurus and Tyrannosaurus. This new dinosaur is estimated to be relatively small, with an adult skull length estimated at 25 inches, compared to 60 inches for T. rex. The new species likely inhabited a seasonally extreme, high-latitude continental environment on the northernmost edge of Cretaceous North America.

The authors suggest that the smaller body size of N. hoglundi compared to most tyrannosaurids from lower latitudes may reflect an adaptation to variability in resources in the arctic seasons. Further diversification may stem from the dinosaurs’ partial isolation in the north by land barriers, such as the east-west running Brooks Range. Although the preserved elements of N. hoglundi are fragments, the authors point to morphological data to provide support for its place among derived tyrannosaurines. This discovery may provide new insights into the adaptability and evolution of tyrannosaurs in a different environment, the Arctic.

“The ‘pygmy tyrannosaur’ alone is really cool because it tells us something about what the environment was like in the ancient Arctic,” said Fiorillo. “But what makes this discovery even more exciting is that Nanuqsaurus hoglundi also tells us about the biological richness of the ancient polar world during a time when the Earth was very warm compared to today.”

First discovery of dinosaur fossils in Malaysia

A team of palaeontology researchers from the Department of Geology, Faculty of Science, University of Malaya and Japanese universities (Waseda University and Kumamoto University) has found dinosaur fossil teeth in the rural interiors of Pahang — the first known discovery of dinosaur remains in Malaysia.

We have started our collaboration and carried out field expeditions to search for potential dinosaur deposits in Malaysia since Sep. 2012. Recently, we have successfully confirmed the presence of dinosaur remains (fossilised teeth) in Pahang,” said lead researcher, Dr. Masatoshi Sone.

“Acting as a team leader, and one of the collaborators, Professor Ren Hirayama from Waseda University (Tokyo), a specialist in reptile palaeontology, identified that one of the teeth, Sample UM10575, belongs to a spinosaurid dinosaur (known as a carnivorous “fish-eating” dinosaur),” he added.

UM10575 is about 23mm long and 10mm wide. It develops fairly distinct carinae (front and rear edges) with serrations, typical to a tooth of a theropod (carnivorous dinosaur). Well-marked coarse ridges are developed on the surface of the tooth, and the surface bears micro-ornament (very fine sculptures); these characterise a spinosaurid tooth.

The new fossils were found from sedimentary rock strata of late Mesozoic age, most likely Cretaceous (ca. 145-75 million years ago). In the interior of Peninsular Malaysia, Jurassic¬-Cretaceous sediments are known to be widely distributed, so that the team researchers have targeted a potential dinosaur deposit there since.

It is expected that large deposits of dinosaur fossils still remain in Malaysia. We currently continue further research and hope to conduct more extensive field investigations that may disclose more significant finds.

Alongside making the public announcement of this discovery, it is urgent to take measures for the protection and conservation of the present fossil site (and to make it accessible only to the qualified researchers). Since the site is in the open area, it is concerned that, once the public is aware, some destruction due to lawless excavations by private fossil collectors and/or robbers may happen, as has happened, for example, in Thailand, Laos, and Mongolia.

It is also hoped that the current discovery can lead to development of palaeontology study in the country and to eventually establish a Malaysian dinosaur museum in a near future.

Revision to rules for color in dinosaurs suggests connection between color and physiology

New research that revises the rules allowing scientists to decipher color in dinosaurs may also provide a tool for understanding the evolutionary emergence of flight and changes in dinosaur physiology prior to its origin.

In a survey comparing the hair, skin, fuzz and feathers of living terrestrial vertebrates and fossil specimens, a research team from The University of Texas at Austin, the University of Akron, the China University of Geosciences and four other Chinese institutions found evidence for evolutionary shifts in the rules that govern the relationship between color and the shape of pigment-containing organelles known as melanosomes, as reported in the Feb. 13 edition of Nature.

At the same time, the team unexpectedly discovered that ancient maniraptoran dinosaurs, paravians, and living mammals and birds uniquely shared the evolutionary development of diverse melanosome shapes and sizes. (Diversity in the shape and size of melanosomes allows scientists to decipher color.) The evolution of diverse melanosomes in these organisms raises the possibility that melanosome shape and size could yield insights into dinosaur physiology.

Melanosomes have been at the center of recent research that has led scientists to suggest the colors of ancient fossil specimens covered in fuzz or feathers.

Melanosomes contain melanin, the most common light-absorbing pigment found in animals. Examining the shape of melanosomes from fossil specimens, scientists have recently suggested the color of several ancient species, including the fuzzy first-discovered feathered dinosaur Sinosauropteryx, and feathered species like Microraptor and Anchiornis.

According to the new research, color-decoding works well for some species, but the color of others may be trickier than thought to reconstruct.

Comparing melanosomes of 181 extant specimens, 13 fossil specimens and all previously published data on melanosome diversity, the researchers found that living turtles, lizards and crocodiles, which are ectothermic (commonly known as cold-blooded), show much less diversity in the shape of melanosomes than birds and mammals, which are endothermic (warm-blooded, with higher metabolic rates).

The limited diversity in melanosome shape among living ectotherms shows little correlation to color. The same holds true for fossil archosaur specimens with fuzzy coverings scientists have described as “protofeathers” or “pycnofibers.” In these specimens, melanosome shape is restricted to spherical forms like those in modern reptiles, throwing doubt on the ability to decipher the color of these specimens from fossil melanosomes.

In contrast, in the dinosaur lineage leading to birds, the researchers found an explosion in the diversity of melanosome shape and size that appears to correlate to an explosion of color within these groups. The shift in diversity took place abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs.

“This points to a profound change at a pretty discrete point,” says author Julia Clarke of The University of Texas at Austin’s Jackson School of Geosciences. “We’re seeing an explosion of melanosome diversity right before the origin of flight associated with the origin of feathers.”

What surprised the researchers was a similarity in the pattern of melanosome diversity among ancient maniraptoran dinosaurs, paravians, and living mammals and birds.

“Only in living, warm-blooded vertebrates that independently evolved higher metabolic rates do we see the melanosome diversity we also see in feathered dinosaurs,” said co-author Matthew Shawkey of The University of Akron.

Many of the genes involved in the melanin color system are also involved in other core processes such as food intake, the stress axis, and reproductive behaviors. Because of this, note the researchers, it is possible that the evolution of diverse melanosome shapes is linked to larger changes in energetics and physiology.

Melanosome shape could end up offering a new tool for studying endothermy in fossil specimens, a notoriously challenging subject for paleontologists.

Because the explosion of diversity in melanosomes appears to have taken place right at the origin of pinnate feathers, the change may indicate that a key shift in dinosaurian physiology occurred prior to the origin of flight.

“We are far from understanding the exact nature of the shift that may have occurred,” says Clarke. “But if changes in genes involved in both coloration and other aspects of physiology explain the pattern we see, these precede flight and arise close to the origin of feathers.”

It is possible, notes Clarke, that a diversity in melanosome shape (and correlated color changes) resulted from an increased evolutionary role for signaling and sexual selection that had a carryover effect on physiology, or that a change in physiology closely preceded changes in color patterning. At this point, she stresses, both ideas are speculative.

“What is interesting is that trying to get at color in extinct animals may have just started to give us some insights into changes in the physiology of dinosaurs.”


‘Steak-knife’ teeth reveal ecology of oldest land predators

The first top predators to walk on land were not afraid to bite off more than they could chew, a University of Toronto Mississauga study has found.

Graduate student and lead author Kirstin Brink along with Professor Robert Reisz from U of T Mississauga’s Department of Biology suggest that Dimetrodon, a carnivore that walked on land between 298 million and 272 million years ago, was the first terrestrial vertebrate to develop serrated ziphodont teeth.

According to the study published in Nature Communications, ziphodont teeth, with their serrated edges, produced a more-efficient bite and would have allowed Dimetrodon to eat prey much larger than itself.

While most meat-eating dinosaurs possessed ziphodont teeth, fossil evidence suggests serrated teeth first evolved in Dimetrodon some 40 million years earlier than theropod dinosaurs.

“Technologies such as scanning electron microscope (SEM) and histology allowed us to examine these teeth in detail to reveal previously unknown patterns in the evolutionary history of Dimetrodon,” Brink said.

The four-meter-long Dimetrodon was the top of the terrestrial food chain in the Early Permian Period and is considered to be the forerunner of mammals.

According to Brink and Reisz’s research, Dimetrodon had a diversity of previously unknown tooth structures and were also the first terrestrial vertebrate to develop cusps — teeth with raised points on the crown, which are dominant in mammals.

The study also suggests ziphodont teeth were confined to later species of Dimetrodon, indicating a gradual change in feeding habits.

“This research is an important step in reconstructing the structure of ancient complex communities,” Reisz said.

“Teeth tell us a lot more about the ecology of animals than just looking at the skeleton.”

“We already know from fossil evidence which animals existed at that time but now with this type of research we are starting to piece together how the members of these communities interacted.”

Brink and Reisz studied the changes in Dimetrodon teeth across 25 million years of evolution.

The analysis indicated the changes in tooth structure occurred in the absence of any significant evolution in skull morphology. This, Brink and Reisz suggest, indicates a change in feeding style and trophic interactions.

“The steak knife configuration of these teeth and the architecture of the skull suggest Dimetrodon was able to grab and rip and dismember large prey,” Reisz said.

“Teeth fossils have attracted a lot of attention in dinosaurs but much less is known about the animals that lived during this first chapter in terrestrial evolution.”

 

How Could Dinosaurs Weigh Up to 80 Tons? New Research On Sauropod Gigantism

Jan. 14, 2014 — Sauropods, the largest land animals in Earth’s history, are still mightily puzzling the scientists. These plant-eating dinosaurs with their long necks and small heads could reach a height of 10 meters or more and dominated all other land vertebrates in terms of size. They could weigh up to 80 tons, more than any other known land vertebrate. One question that has been intensely debated is how these giants of the animal kingdom regulated their own body temperature.

According to the calculations of the Mainz-based ecologist, the body temperature of these animals did not increase with body weight. Her estimates indicate that sauropods may have had an average body temperature of some 28 degrees Celsius. The upper limit for the body temperature that can be tolerated by vertebrate species living today is 45 degrees Celsius. The body temperatures that Griebeler postulates for the sauropods are thus well below those of today’s endothermic vertebrates but consistent with those of ectothermic monitor lizards. Her calculations of sauropod body temperature take into account the relationship between the maximum rate of growth and the basal metabolic rate of an animal, whereby the latter is largely determined by body temperature.

Griebeler’s work is part of a collection that brings together the results of recent research into sauropod gigantism. The gigantism of these vertebrates, unique in the history of Earth, raises many questions, such as why no other land creatures have ever achieved this size and what their bauplan, physiology, and life cycle would have been like. The collection put together by the leading open access journal PLOS ONE consists of 14 contributions from the fields of ecology, morphology, animal nutrition, and paleontology that all address the fundamental question of how the sauropods managed to become so extraordinarily massive.

“We are pleased that this new research is freely accessible not only to other scientists, but also to sauropod fans,” said PD Dr. Eva Maria Griebeler. She and Dr. Jan Werner are members of the research group “Biology of the Sauropod Dinosaurs: The Evolution of Gigantism (FOR 533),” funded by the German Research Foundation (DFG). The collection was initiated as a result of a related international conference on this subject. Both scientists from the Ecology division at the Institute of Zoology at Mainz University have been working for more than six years within this research group. They have written three of the 14 contributions in the collection.

In one article, Jan Werner and his colleague Koen Stein of the University of Bonn describe a new method of determining the density of bone tissue and juxtapose sauropod data and results extrapolated for comparable endothermic mammals. Although the bone structure and the density of certain tissues of sauropods were similar to those of today’s mammals, the results do not conclusively demonstrate that sauropods were also endothermic animals. Other functional aspects, such as similar weight-bearing stresses, could have resulted in the development of convergent forms of bone tissue.

Another article looks at the reproductive biology of sauropods. Here Werner and Griebeler discuss the hypothesis that a high rate of reproduction contributed to the gigantism of the large dinosaurs. They discovered that the reproductive pattern of most dinosaurs was similar to that of modern reptiles and birds. The reproductive pattern of theropods, i.e., ancestors of the modern birds, turned out to be comparable with that of birds, prosauropods, and sauropods rather than reptiles. However, contrary to the assumptions of previous studies, the calculations of the Mainz scientists did not corroborate the hypothesis that the large dinosaurs would have laid a particularly large number of eggs. In terms of total eggs produced annually, this number could not have exceeded 200 to 400 eggs for a sauropod weighing 75 tons. Today’s large sea turtles are known to lay clutches in this range.

First Dinosaurs Identified from Saudi Arabia

Jan. 7, 2014 — Dinosaur fossils are exceptionally rare in the Arabian Peninsula. An international team of scientists from Uppsala University, Museum Victoria, Monash University, and the Saudi Geological Survey have now uncovered the first record of dinosaurs from Saudi Arabia.

What is now dry desert was once a beach littered with the bones and teeth of ancient marine reptiles and dinosaurs.

A string of vertebrae from the tail of a huge “Brontosaurus-like” sauropod, together with some shed teeth from a carnivorous theropod represent the first formally identified dinosaur fossils from Saudi Arabia, and were found in the north-western part of the Kingdom along the coast of the Red Sea.

The remains were discovered during excavations conducted by a team of scientists working under the auspices of the Saudi Geological Survey, Jeddah.

The dinosaur finds were recently published in the scientific journal PLOS ONE and jointly authored by participating researchers from Sweden, Australia and Saudi Arabia.

“Dinosaur fossils are exceptionally rare in the Arabian Peninsula, with only a handful of highly fragmented bones documented this far” says Dr Benjamin Kear, based at Uppsala University in Sweden and lead author of the study.

“This discovery is important not only because of where the remains were found, but also because of the fact that we can actually identify them. Indeed, these are the first taxonomically recognizable dinosaurs reported from the Arabian Peninsula” Dr Kear continues.

“Dinosaur remains from the Arabian Peninsula and the area east of the Mediterranean Sea are exceedingly rare because sedimentary rocks deposited in streams and rivers during the Age of Dinosaurs are rare, particularly in Saudi Arabia itself” says Dr Tom Rich from Museum Victoria in Australia.

When these dinosaurs were alive, the Arabian landmass was largely underwater and formed the north-western coastal margin of the African continent.

“The hardest fossil to find is the first one. Knowing that they occur in a particular area and the circumstances under which they do, makes finding more fossils significantly less difficult” says Dr Rich.

The teeth and bones are approximately 72 million years old.

Two types of dinosaur were described from the assemblage, a bipedal meat-eating abelisaurid distantly related to Tyrannosaurus but only about six metres long, and a plant-eating titanosaur perhaps up to 20 metres in length.

Similar dinosaurs have been found in North Africa, Madagascar and as far away as South America.

Mapping the Demise of the Dinosaurs

Dec. 9, 2013 — About 65 million years ago, an asteroid or comet crashed into a shallow sea near what is now the Yucatán Peninsula of Mexico. The resulting firestorm and global dust cloud caused the extinction of many land plants and large animals, including most of the dinosaurs. At this week’s meeting of the American Geophysical Union (AGU) in San Francisco, MBARI researchers will present evidence that remnants from this devastating impact are exposed along the Campeche Escarpment — an immense underwater cliff in the southern Gulf of Mexico.

The ancient meteorite impact created a huge crater, over 160 kilometers across. Unfortunately for geologists, this crater is almost invisible today, buried under hundreds of meters of debris and almost a kilometer of marine sediments. Although fallout from the impact has been found in rocks around the world, surprisingly little research has been done on the rocks close to the impact site, in part because they are so deeply buried. All existing samples of impact deposits close to the crater have come from deep boreholes drilled on the Yucatán Peninsula.

In March 2013, an international team of researchers led by Charlie Paull of the Monterey Bay Aquarium Research Institute (MBARI) created the first detailed map of the Campeche Escarpment. The team used multi-beam sonars on the research vessel Falkor, operated by the Schmidt Ocean Institute. The resulting maps have recently been incorporated in Google Maps and Google Earth for viewing by researchers and the general public.

Paull has long suspected that rocks associated with the impact might be exposed along the Campeche Escarpment, a 600-kilometer-long underwater cliff just northwest of the Yucatán Peninsula. Nearly 4,000 meters tall, the Campeche Escarpment is one of the steepest and tallest underwater features on Earth. It is comparable to one wall of the Grand Canyon — except that it lies thousands of meters beneath the sea.

As in the walls of the Grand Canyon, sedimentary rock layers exposed on the face of the Campeche Escarpment provide a sequential record of the events that have occurred over millions of years. Based on the new maps, Paull believes that rocks formed before, during, and after the impact are all exposed along different parts of this underwater cliff.

Just as a geologist can walk the Grand Canyon, mapping layers of rock and collecting rock samples, Paull hopes to one day perform geologic “fieldwork” and collect samples along the Campeche Escarpment. Only a couple of decades ago, the idea of performing large-scale geological surveys thousands of meters below the ocean surface would have seemed a distant fantasy. Over the last eight years, however, such mapping has become almost routine for MBARI geologists using underwater robots.

The newly created maps of the Campeche Escarpment could open a new chapter in research about one of the largest extinction events in Earth’s history. Already researchers from MBARI and other institutions are using these maps to plan additional studies in this little-known area. Detailed analysis of the bathymetric data and eventual fieldwork on the escarpment will reveal fascinating new clues about what happened during the massive impact event that ended the age of the dinosaurs — clues that have been hidden beneath the waves for 65 million years.

In addition to the Schmidt Ocean Institute, Paull’s collaborators in this research included Jaime Urrutia-Fucugauchi from the Universidad Nacional Autónoma de Mexico and Mario Rebolledo- Vieyra of the Centro de Investigación Científica de Yucatán. Paull also worked closely with MBARI researchers, including geophysicist and software engineer Dave Caress, an expert on processing of multibeam sonar data, and geologist Roberto Gwiazda, who served as project manager and will be describing this research at the AGU meeting.

Functional Importance of Dinosaur Beaks Illuminated

Dec. 2, 2013 — Why beaks evolved in some theropod dinosaurs and what their function might have been is the subject of new research by an international team of palaeontologists published this week in PNAS (Proceedings of the National Academy of Sciences).

Beaks are a typical hallmark of modern birds and can be found in a huge variety of forms and shapes. However, it is less well known that keratin-covered beaks had already evolved in different groups of dinosaurs during the Cretaceous Period.

Employing high-resolution X-ray computed tomography (CT scanning) and computer simulations, Dr Stephan Lautenschlager and Dr Emily Rayfield of the University of Bristol with Dr Perle Altangerel (National University of Ulaanbaatar) and Professor Lawrence Witmer (Ohio University) used digital models to take a closer look at these dinosaur beaks.

The focus of the study was the skull of Erlikosaurus andrewsi, a 3-4m (10-13ft) large herbivorous dinosaur called a therizinosaur, which lived more than 90 million years ago during the Cretaceous Period in what is now Mongolia, and which shows evidence that part of its snout was covered by a keratinous beak.

This new study reveals that keratinous beaks played an important role in stabilizing the skeletal structure during feeding, making the skull less susceptible to bending and deformation.

Lead author Dr Stephan Lautenschlager of Bristol’s School of Earth Sciences said: “It has classically been assumed that beaks evolved to replace teeth and thus save weight, as a requirement for the evolution of flight. Our results, however, indicate that keratin beaks were in fact beneficial to enhance the stability of the skull during biting and feeding.”

Co-author Dr Emily Rayfield, Reader of Palaeobiology at Bristol said: “Using Finite Element Analysis, a computer modelling technique routinely used in engineering, we were able to deduce very accurately how bite and muscle forces affected the skull of Erlikosaurus during the feeding process. This further allowed us to identify the importance of soft-tissue structures, such as the keratinous beak, which are normally not preserved in fossils.”

Co-author Lawrence Witmer, Chang Professor of Paleontology at the Ohio University Heritage College of Osteopathic Medicine said: “Beaks evolved several times during the transitions from dinosaurs to modern birds, usually accompanied by the partial or complete loss of teeth and our study now shows that keratin-covered beaks represent a functional innovation during dinosaur evolution.”

This work was funded by a research fellowship to Stephan Lautenschlager from the German Volkswagen Foundation and grants from the National Science Foundation to Lawrence

New Evidence for Warm-Blooded Dinosaurs

July 17, 2013 — University of Adelaide research has shown new evidence that dinosaurs were warm-blooded like birds and mammals, not cold-blooded like reptiles as commonly believed.
In a paper published in PLoS ONE, Professor Roger Seymour of the University’s School of Earth and Environmental Sciences, argues that cold-blooded dinosaurs would not have had the required muscular power to prey on other animals and dominate over mammals as they did throughout the Mesozoic period.

“Much can be learned about dinosaurs from fossils but the question of whether dinosaurs were warm-blooded or cold-blooded is still hotly debated among scientists,” says Professor Seymour.

“Some point out that a large saltwater crocodile can achieve a body temperature above 30°C by basking in the sun, and it can maintain the high temperature overnight simply by being large and slow to change temperature.

“They say that large, cold-blooded dinosaurs could have done the same and enjoyed a warm body temperature without the need to generate the heat in their own cells through burning food energy like warm-blooded animals.”

In his paper, Professor Seymour asks how much muscular power could be produced by a crocodile-like dinosaur compared to a mammal-like dinosaur of the same size.

Saltwater crocodiles reach over a tonne in weight and, being about 50% muscle, have a reputation for being extremely powerful animals.

But drawing from blood and muscle lactate measurements collected by his collaborators at Monash University, University of California and Wildlife Management International in the Northern Territory, Professor Seymour shows that a 200 kg crocodile can produce only about 14% of the muscular power of a mammal at peak exercise, and this fraction seems to decrease at larger body sizes.

“The results further show that cold-blooded crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in warm-blooded mammals,” says Professor Seymour.

“So, despite the impression that saltwater crocodiles are extremely powerful animals, a crocodile-like dinosaur could not compete well against a mammal-like dinosaur of the same size.

“Dinosaurs dominated over mammals in terrestrial ecosystems throughout the Mesozoic. To do that they must have had more muscular power and greater endurance than a crocodile-like physiology would have allowed.”

His latest evidence adds to that of earlier work he did on blood flow to leg bones which concluded that the dinosaurs were possibly even more active than mammals.

Big-Nosed, Long-Horned Dinosaur Discovered in Utah: Dinosaur in Same Family as Triceratops

July 17, 2013 — A remarkable new species of horned dinosaur has been unearthed in Grand Staircase-Escalante National Monument, southern Utah. The huge plant-eater inhabited Laramidia, a landmass formed when a shallow sea flooded the central region of North America, isolating western and eastern portions for millions of years during the Late Cretaceous Period. The newly discovered dinosaur, belonging to the same family as the famous Triceratops, was announced today in the British scientific journal, Proceedings of the Royal Society B.
The study, funded in large part by the Bureau of Land Management and the National Science Foundation, was led by Scott Sampson, when he was the Chief Curator at the Natural History Museum of Utah at the University of Utah. Sampson is now the Vice President of Research and Collections at the Denver Museum of Nature & Science. Additional authors include Eric Lund (Ohio University; previously a University of Utah graduate student), Mark Loewen (Natural History Museum of Utah and Dept. of Geology and Geophysics, University of Utah), Andrew Farke (Raymond Alf Museum), and Katherine Clayton (Natural History Museum of Utah).

Horned dinosaurs, or “ceratopsids,” were a group of big-bodied, four-footed herbivores that lived during the Late Cretaceous Period. As epitomized by Triceratops, most members of this group have huge skulls bearing a single horn over the nose, one horn over each eye, and an elongate, bony frill at the rear. The newly discovered species, Nasutoceratops titusi, possesses several unique features, including an oversized nose relative to other members of the family, and exceptionally long, curving, forward-oriented horns over the eyes. The bony frill, rather than possessing elaborate ornamentations such as hooks or spikes, is relatively unadorned, with a simple, scalloped margin. Nasutoceratops translates as “big-nose horned face,” and the second part of the name honors Alan Titus, Monument Paleontologist at Grand Staircase-Escalante National Monument, for his years of research collaboration.

For reasons that have remained obscure, all ceratopsids have greatly enlarged nose regions at the front of the face. Nasutoceratops stands out from its relatives, however, in taking this nose expansion to an even greater extreme. Scott Sampson, the study’s lead author, stated, “The jumbo-sized schnoz of Nasutoceratops likely had nothing to do with a heightened sense of smell — since olfactory receptors occur further back in the head, adjacent to the brain — and the function of this bizarre feature remains uncertain.”

Paleontologists have long speculated about the function of horns and frills on horned dinosaurs. Ideas have ranged from predator defense and controlling body temperature to recognizing members of the same species. Yet the dominant hypothesis today focuses on competing for mates — that is, intimidating members of the same sex and attracting members of the opposite sex. Peacock tails and deer antlers are modern examples. In keeping with this view, Mark Loewen, a co-author of the study claimed that, “The amazing horns of Nasutoceratops were most likely used as visual signals of dominance and, when that wasn’t enough, as weapons for combatting rivals.”

A Treasure Trove of Dinosaurs on the Lost Continent of Laramidia

Nasutoceratops was discovered in Grand Staircase-Escalante National Monument (GSENM), which encompasses 1.9 million acres of high desert terrain in south-central Utah. This vast and rugged region, part of the National Landscape Conservation System administered by the Bureau of Land Management, was the last major area in the lower 48 states to be formally mapped by cartographers. Today GSENM is the largest national monument in the United States. Sampson proclaimed that, “Grand Staircase-Escalante National Monument is the last great, largely unexplored dinosaur boneyard in the lower 48 states.”

For most of the Late Cretaceous, exceptionally high sea levels flooded the low-lying portions of several continents around the world. In North America, a warm, shallow sea called the Western Interior Seaway extended from the Arctic Ocean to the Gulf of Mexico, subdividing the continent into eastern and western landmasses, known as Appalachia and Laramidia, respectively. Whereas little is known of the plants and animals that lived on Appalachia, the rocks of Laramidia exposed in the Western Interior of North America have generated a plethora of dinosaur remains. Laramidia was less than one-third the size of present day North America, approximating the area of Australia.

Most known Laramidian dinosaurs were concentrated in a narrow belt of plains sandwiched between the seaway to the east and mountains to the west. Today, thanks to an abundant fossil record and more than a century of collecting by paleontologists, Laramidia is the best known major landmass for the entire Age of Dinosaurs, with dig sites spanning from Alaska to Mexico. Utah was located in the southern part of Laramidia, which has yielded far fewer dinosaur remains than the fossil-rich north. The world of dinosaurs was much warmer than the present day; Nasutoceratops lived in a subtropical swampy environment about 100 km from the seaway.

Beginning in the 1960’s, paleontologists began to notice that the same major groups of dinosaurs seemed to be present all over this Late Cretaceous landmass, but different species of these groups occurred in the north (for example, Alberta and Montana) than in the south (New Mexico and Texas). This finding of “dinosaur provincialism” was very puzzling, given the giant body sizes of many of the dinosaurs together with the diminutive dimensions of Laramidia. Currently, there are five giant (rhino-to-elephant-sized) mammals on the entire continent of Africa. Seventy-six million years ago, there may have been more than two dozen giant dinosaurs living on a landmass about one-quarter that size. Co-author Mark Loewen noted that, “We’re still working to figure out how so many different kinds of giant animals managed to co-exist on such a small landmass?” The new fossils from GSENM are helping us explore the range of possible answers, and even rule out some alternatives.

During the past dozen years, crews from the Natural History Museum of Utah, the Denver Museum of Nature & Science and several other partner institutions (e.g., the Utah Geologic Survey, the Raymond Alf Museum of Paleontology, and the Bureau of Land Management) have unearthed a new assemblage of more than a dozen dinosaurs in GSENM. In addition to Nasutoceratops, the collection includes a variety of other plant-eating dinosaurs — among them duck-billed hadrosaurs, armored ankylosaurs, dome-headed pachycephalosaurs, and two other horned dinosaurs, Utahceratops and Kosmoceratops — together with carnivorous dinosaurs great and small, from “raptor-like” predators to a mega-sized tyrannosaur named Teratophoneus. Amongst the other fossil discoveries are fossil plants, insect traces, clams, fishes, amphibians, lizards, turtles, crocodiles, and mammals. Together, this diverse bounty of fossils is offering one of the most comprehensive glimpses into a Mesozoic ecosystem. Remarkably, virtually all of the identifiable dinosaur remains found in GSENM belong to new species, providing strong support for the dinosaur provincialism hypothesis.

Andrew Farke, a study co-author, noted that, “Nasutoceratops is one of a recent landslide of ceratopsid discoveries, which together have established these giant plant-eaters as the most diverse dinosaur group on Laramidia.”

Eric Lund, another co-author as well as the discoverer of the new species, stated that, “Nasutoceratops is a wondrous example of just how much more we have to learn about with world of dinosaurs. Many more exciting fossils await discovery in Grand Staircase-Escalante National Monument.”