The question of whether the Late Jurassic dino-bird Archaeopteryx was an elaborately feathered ground dweller, a glider, or an active flyer has fascinated palaeontologists for decades. Valuable new information obtained with state-of-the-art synchrotron microtomography at the ESRF, the European Synchrotron (Grenoble, France), allowed an international team of scientists to answer this question in Nature Communications. The wing bones of Archaeopteryx were shaped for incidental active flight, but not for the advanced style of flying mastered by today's birds.

The Munich specimen of the transitional bird Archaeopteryx. It preserves a partial skull (top left), shoulder girdle and both  wings slightly raised up (most left to center left), the ribcage (center), and the pelvic girdle and both legs in a 'cycling' posture (right); all connected by the vertebral column from the neck (top left, under the skull) to the tip of the tail (most right). Imprints of its wing feathers are visible radiating from below the shoulder and vague imprints of the tail plumage can be recognized extending from the tip of the tail [Credit: ESRF/Pascal Goetgheluck]

Was Archaeopteryx capable of flying, and if so, how? Although it is common knowledge that modern-day birds descended from extinct dinosaurs, many questions on their early evolution and the development of avian flight remain unanswered. Traditional research methods have thus far been unable to answer the question whether Archaeopteryx flew or not. Using synchrotron microtomography at the ESRF's beamline ID19 to probe inside Archaeopteryx fossils, an international team of scientists from the ESRF, Palacký University, Czech Republic, CNRS and Sorbonne University, France, Uppsala University, Sweden, and Bürgermeister-Müller-Museum Solnhofen, Germany, shed new light on this earliest of birds.

Reconstructing extinct behaviour poses substantial challenges for palaeontologists, especially when it comes to enigmatic animals such as the famous Archaeopteryx from the Late Jurassic sediments of southeastern Germany that is considered the oldest potentially free-flying dinosaur. This well-preserved fossil taxon shows a mosaic anatomy that illustrates the close family relations between extinct raptorial dinosaurs and living dinosaurs: the birds. Most modern bird skeletons are highly specialised for powered flight, yet many of their characteristic adaptations in particularly the shoulder are absent in the Bavarian fossils of Archaeopteryx. Although its feathered wings resemble those of modern birds flying overhead every day, the primitive shoulder structure is incompatible with the modern avian wing beat cycle.

The Munich specimen of Archaeopteryx at beamline ID19 at the ESRF. The limestone plate was mounted on a rotating sample stage and the beam is here centered on the skull using lasers. The X-ray beam, coming from the right of the picture, travels through the sample and arrives at the detector (visible left) where a camera records the signal [Credit: ESRF/Pascal Goetgheluck]

"The cross-sectional architecture of limb bones is strongly influenced by evolutionary adaptation towards optimal strength at minimal mass, and functional adaptation to the forces experienced during life," explains Prof. Jorge Cubo of the Sorbonne University in Paris. "By statistically comparing the bones of living animals that engage in observable habits with those of cryptic fossils, it is possible to bring new information into an old discussion," says senior author Dr. Sophie Sanchez from Uppsala University, Sweden

Archaeopteryx skeletons are preserved in and on limestone slabs that reveal only part of their morphology. Since these fossils are among the most valuable in the world, invasive probing to reveal obscured or internal structures is therefore highly discouraged. "Fortunately, today it is no longer necessary to damage precious fossils," states Dr. Paul Tafforeau, beamline scientist at the ESRF. "The exceptional sensitivity of X-ray imaging techniques for investigating large specimens that is available at the ESRF offers harmless microscopic insight into fossil bones and allows virtual 3D reconstructions of extraordinary quality. Exciting upgrades are underway, including a substantial improvement of the properties of our synchrotron source and a brand new beamline designated for tomography. These developments promise to give even better results on much larger specimens in the future."

Dennis Voeten indicates the bone wall thickness of the 'Chicken Wing' specimen of Archaeopteryx on the top computer screen for comparison against the bone walls of a primitive pterosaur on the bottom screen. A three-dimensional model of the 'Chicken Wing' is held up, the referred bone cross section is that of the humerus, the uppermost arm bone visible most right on the 3-D-printed model [Credit: ESRF]

Scanning data unexpectedly revealed that the wing bones of Archaeopteryx, contrary to its shoulder girdle, shared important adaptations with those of modern flying birds. "We focused on the middle part of the arm bones because we knew those sections contain clear flight-related signals in birds," says Dr. Emmanuel de Margerie, CNRS, France. "We immediately noticed that the bone walls of Archaeopteryx were much thinner than those of earthbound dinosaurs but looked a lot like conventional bird bones," continues lead author Dennis Voeten of the ESRF. "Data analysis furthermore demonstrated that the bones of Archaeopteryx plot closest to those of birds like pheasants that occasionally use active flight to cross barriers or dodge predators, but not to those of gliding and soaring forms such as many birds of prey and some seabirds that are optimised for enduring flight."

"We know that the region around Solnhofen in southeastern Germany was a tropical archipelago, and such an environment appears highly suitable for island hopping or escape flight," remarks Dr. Martin Röper, Archaeopteryx curator and co-author of the report. "Archaeopteryx shared the Jurassic skies with primitive pterosaurs that would ultimately evolve into the gigantic pterosaurs of the Cretaceous. We found similar differences in wing bone geometry between primitive and advanced pterosaurs as those between actively flying and soaring birds," adds Vincent Beyrand of the ESRF.

Since Archaeopteryx represents the oldest known flying member of the avialan lineage that also includes modern birds, these findings not only illustrate aspects of the lifestyle of Archaeopteryx but also provide insight into the early evolution of dinosaurian flight. "Indeed, we now know that Archaeopteryx was already actively flying around 150 million years ago, which implies that active dinosaurian flight had evolved even earlier!" says Prof. Stanislav Bureš of Palacký University in Olomouc. "However, because Archaeopteryx lacked the pectoral adaptations to fly like modern birds, the way it achieved powered flight must also have been different. We will need to return to the fossils to answer the question on exactly how this Bavarian icon of evolution used its wings," concludes Voeten.

It is now clear that Archaeopteryx is a representative of the first wave of dinosaurian flight strategies that eventually went extinct, leaving only the modern avian flight stroke directly observable today.

Source: European Synchrotron Radiation Facility [March 13, 2018]

Fossils of six new species of pterosaurs - giant flying reptiles that flew over the heads of the dinosaurs - have been discovered by a research team led by the Milner Centre for Evolution at the University of Bath, revealing that this lineage was killed off in its prime. An analysis of the fossils, published in the open access journal PLOS Biology shows that, contrary to previous studies, there was still remarkable diversity among pterosaurs up to the point of their extinction.

Some of the Moroccan pterosaur fossils from the study. Top: the mandible (lower jaw) of Alcione elainus, a small pterosaur newly described in this paper. Bottom: part of the ulna (forearm bone) from a giant pterosaur, tentatively identified as Arambourgiania. Note the different scales - the mandible is less than 20 cm long, while the ulna is more than 40 cm long; Arambourgiania would have had a wingspan more than three times that of Alcione [Credit: pbio.2001663]

Pterosaurs - prehistoric reptiles popularly known as pterodactyls - were flying cousins of the dinosaurs. Soaring on skin wings supported by a single huge finger, they were the largest animals ever to take wing.

The pterosaurs were previously thought to be declining before the mass extinction at the end of the Cretaceous period, which was caused by an asteroid impact 66 million years ago. However, hundreds of new fossils from the end of the Cretaceous, discovered at sites in northern Morocco, show that the region supported seven species of pterosaur from three different families. It was thought that the rarity of pterosaur fossils from the end of the dinosaur era meant that they were slowly going extinct. But the new study shows that the data had been misleadingly skewed by the dearth of fossils and that the pterosaurs at this time were actually far more diverse than thought.

The new pterosaurs ranged in wingspan from a little over two meters to almost ten meters (from 6 to 30 feet) - almost three times bigger than the largest living bird - and weighed up to 200 kg (440 pounds). The fossils date to just over 66 million years ago, the very end of the Cretaceous period, making these pterosaurs among the last of their kind on Earth. As well as the diversity in size, the authors were also able to show that the species differed significantly in the shape and size of parts of their bodies (such as beak shape, neck length, and wing proportions), suggesting that they occupied distinct ecological niches.

Dr Nick Longrich, from the Milner Centre for Evolution and the Department of Biology & Biochemistry at the University of Bath, and the study's lead author, said: "To grow so large and still be able to fly, pterosaurs evolved incredibly lightweight skeletons, with the bones reduced to thin-walled, hollow tubes like the frame of a carbon-fiber racing bike.

"But unfortunately, that means these bones are fragile, and so almost none survive as fossils."

Longrich said he had always found pterosaurs fascinating, and as a university student had dreamed of studying them. Years later in Morocco, he would stumble across a single, small bone mixed in with fossil fish dug up from a phosphate mine. "It was like a light went off," he said. "I remembered back to the Illustrated Encyclopedia of Pterosaurs, a book I'd practically memorized as an undergraduate. And I thought 'that's a nyctosaur.'"

Nyctosaurs, a family of small pterosaurs, hadn't been proven to survive to the end of the Cretaceous. On a hunch, he looked for more pterosaurs, and found more species - including Tethydraco, a member of the pteranodontids, a family that had been thought to disappear fifteen million years earlier. In addition to the single species previously found in the area, six additional species turned up. "I believe there are many more species to find," he said.

Co-author of the study, Professor David Martill from the University of Portsmouth said: "Exciting discoveries are being made all the time, and sometimes, just the smallest of bones can radically change our perception of the history of life on Earth."

Dr Brian Andres, Research Associate at The University of Texas at Austin, also a co-author of the study, added: "The Moroccan fossils tell the last chapter of the pterosaurs' story - and they tell us pterosaurs dominated the skies over the land and sea, as they had for the previous 150 million years."

Moroccan paleontologist Professor Nour-Eddine Jalil from the Muséum national d'Histoire naturelle, France commented: "This is a fabulous discovery of pterosaurs from Morocco - they tell us their amazing diversity while we thought them in decline. "The Moroccan phosphates are an open window on a key moment in the history of the Earth, one that shortly preceded the global crisis that swept away, among others, dinosaurs and marine reptiles."

Source: Public Library of Science [March 13, 2018]

A scientist with the Canadian Museum of Nature has answered a long-standing mystery about why fossils of ankylosaurs -- the "armoured tanks" of the dinosaur world -- are mainly found belly-side up. In doing so, he has ruled out three other competing theories involving clumsiness, predation, and the effects of bloating as seen in armadillo roadkills.

Illustration of Euoplocephalus, an ankylosaur. Ankylosaurids are sometimes called  the 'tanks of the Cretaceous' given their squat bodies and armored hides  [Credit: Brett Booth Brett Booth]

Palaeontologist Dr. Jordan Mallon says the evidence points to a phenomenon called "bloat-and-float," whereby the bloating carcasses of ankylosaurs would end up in a river, flip belly-side up due to the weight of their heavy armour, and then float downstream. The remains would wash ashore, where decomposition and then fossilization would seal the dinosaur remains in their upside-down death pose.

"Textbooks have touted that ankylosaur fossils are usually found upside down, but no one has gone back and checked the records to make sure that's the case," explains Mallon. The observations date from the 1930s. Indeed, the fossils of two star ankylosaurs described in 2017, Borealopelta from Alberta and Zuul from Montana, were found upside down.

Mallon examined 32 ankylosaur fossils from Alberta (of which 26 were found belly up), photos of specimens, field notes, and other signs such as erosion of the exposed surface, sun bleaching, and the presence of lichens.

The results are published in the online journal Palaeogeography, Palaeoclimatology, Palaeoecology. Collaborators included armadillo experts Drs. Colleen McDonough and Jim Loughry of Valdosta State University in Georgia, and Dr. Don Henderson, with Drumheller Alberta's Royal Tyrrell Museum of Palaeontology.

Mallon ruled out three other theories before settling on "bloat-and-float" to explain the preponderance of the belly-up remains.

"One idea was that ankylosaurs were simply clumsy, tripping over themselves or rolling down hills and ending up dying that way," he says. But since ankylosaurs existed for about 100 million years, clumsy habits would not fit with their apparent evolutionary success.

Another theory was that ankylosaurs were prey for carnivores, such as hungry tyrannosaurids, which would flip the armoured dinosaurs onto their backs to get at the soft underbelly. "If this was true, we would expect to see signs of bite marks, especially on upside-down ones, but we saw marks on only one specimen," explains Mallon. "Since they were armoured, it makes sense that ankylosaurs were not regularly preyed upon, and the fossil evidence in museum collections supports this."

The third idea, proposed in the 1980s, is an analogy to what happens with some armadillo roadkills -- as the carcass rots and bloats, gas accumulates, and the limbs would splay out, eventually rolling the animal onto its back.

The challenge was to test this hypothesis. Enter McDonough and Loughry who are experts on modern armadillos, which also have an armoured shell. Over the summer of 2016, they studied 174 examples of dead armadillo. "Sure enough, the data show that they do not occur more often on their backs," says Mallon. The pair even examined dead armadillos placed in plexiglass cases in their backyard to keep away scavengers. Regardless of the positioning of the carcasses, bloating did not cause them to roll over onto their backs.

That left the "bloat-and-float" hypothesis as the most likely explanation for the presence of upside-down fossils. To study this, Mallon turned to computer simulations developed by Dr. Don Henderson, who specializes in the floating behaviour of animals in water.

Ankylosaur fossils in North America are found in river channel deposits, and in the Late Cretaceous Period these animals would have been living along a coastline of what is known as the Western Interior Seaway.

"We designed these models of ankylosaurs, both clubless and clubbed, and looked at their floating behavior," explains Mallon. The computer modelling showed that the animals would tend to flip upside down quite easily in water. Nodosaurids, which are ankylosaurs with no tail clubs, would flip most easily at the slightest tilt; the ankyosaurids (with clubbed tails), were more stable but could still be flipped.

"So 'bloat-and-float'" fits with their known environment, and this research helps inform about the transport behavior of dead dinosaurs, which is important to know when studying fossil ecosystems. Ultimately, this is a classic case study of the scientific method: examining alternative hypotheses, finding ways to test them, and ruling them out one-by-one. What you are left with at the end is the most likely explanation."

Source: Canadian Museum of Nature [February 28, 2018]

A new model based on ground-running birds could predict locomotion of bipedal dinosaurs based on their speed and body size, according to a study published in the open-access journal PLOS ONE by Peter Bishop from the Queensland Museum, Australia and colleagues.

Ground-running bird model may predict bipedal dinosaur locomotion [Credit: Peter Bishop, Queensland Museum]

Previous research has investigated the biomechanics of ground-dwelling birds to better understand the how bipedal non-avian dinosaurs moved, but it has not previously been possible to empirically predict the locomotive forces that extinct dinosaurs experienced, especially those species that were much larger than living birds. Bishop and colleagues examined locomotion in 12 species of ground-dwelling birds, ranging in body mass from 45g to 80kg, as the birds moved at various speeds along enclosed racetracks while cameras recorded their movements and forceplates measured the forces their feet exerted upon the ground.

The researchers found that many physical aspects of bird locomotion change continuously as speed increases. This supports previous evidence that unlike humans, who have distinct "walking" and "running" gaits, birds move in a continuum from "walking" to "running". The authors additionally observed consistent differences in gait and posture between small and large birds.

The researchers used their data to construct the biomechanically informative, regression-derived statistical (BIRDS) Model, which requires just two inputs - body mass and speed - to predict basic features of bird locomotion, including stride length and force exerted per step. The model performed well when tested against known data. While more data are needed to improve the model, and it is unclear if it can be extrapolated to animals of much larger body mass, the researchers hope that it might help predict features of non-avian dinosaur locomotion using data from fossils and footprints.

Source: Public Library of Science [February 21, 2018]

A record of volcanism preserved along ancient mid-ocean ridges provides evidence for heightened worldwide magmatic activity 66 million years ago just after the Chicxulub meteor struck Earth, according to University of Oregon scientists.

Coloured and black points mark the global distribution of mid-ocean ridges, with ages of 66 million years ago created at spreading rates above and below 35 millimeters a year, respectively. Colours indicate the maximum gravity anomaly within 2 degrees [Credit: Joseph Byrnes]

The research, published in Science Advances, points to changes in the strength of gravity above the seafloor, which indicate a transient period of increased volumes of magma being released along ridges that mark the oceanic boundaries of tectonic plates.

Lead author Joseph Byrnes, a former UO doctoral student, says that this global volcanic activity was likely triggered by strong seismic waves radiated from the meteorite impact site. Subsequently accelerated volcanism, he said, likely would have been active during the mass extinction of the world's non-avian dinosaurs.

Volcanism, particularly a massive outpouring of basalt recorded by the Deccan Traps in India, has been in and out of the extinction debate. Rare volcanic events at such a scale are known to cause catastrophic disturbances to Earth's climate and, when they occur, they are often linked to mass extinctions.

Since evidence of the meteor strike near present day Mexico surfaced in the 1980s, scientists have debated whether the impact or the Deccan Traps volcanic eruptions was the primary driver for extinction of the dinosaurs.

Progressively more accurate dating methods indicate that while the Deccan Traps eruptions were active during the mass extinction, they actually began significantly before the Chicxulub impact, said Leif Karlstrom, a professor in the UO's Department of Earth Sciences and co-author on the study with Byrnes.

The amount of seafloor exhibiting small structural anomalies is plotted as a function of the age of seafloor. Trends that  persist over 10 million years have been subtracted to highlight transient features, and only high spreading rates are plotted here. The highest peak, which indicates the production of 8 percent more anomalous seafloor than on average, occurs at 66 million years ago and is coincident with the age of the Chicxulub meteorite impact [Credit: Joseph Byrnes]

The meteor is closely aligned in time with the onset of mass extinction, seeming to indicate a dominant role, he said. Still, the near coincidence in time of such globally catastrophic events continues to spur debate.

In 2015, researchers at the University of California, Berkeley, proposed that the two events might be connected. They suggested that Chixculub may have modulated distant volcanism by sending seismic waves through the Earth and accelerating volcanic activity in the Deccan Traps. Similar to the impacts that normal tectonic earthquakes sometimes have on wells and streams, Karlstrom said, the study proposed that powerful shaking liberated magma stored in the mantle beneath the Deccan Traps and caused the largest eruptions there.

The new National Science Foundation-supported study at the UO adds another layer to the story, said Karlstrom, who also co-authored on the UC-Berkeley research. It suggests that other volcanic activity around the world was triggered by the meteor. Seismic waves moving through the Earth, he said, may have accelerated volcanism already occurring along mid-ocean ridges.

"Our work suggests a connection between these exceedingly rare and catastrophic events, distributed over the entire planet," Karlstrom said. "The meteorite's impact may have influenced volcanic eruptions that were already going on, making for a one-two punch."

The findings emerged as Byrnes, now a postdoctoral researcher at the University of Minnesota, discovered the evidence for volcanic activity by analyzing publicly available global datasets, including two updated in the last decade, on free-air gravity, ocean floor topography and tectonic spreading rates.


In his analyses, Byrnes divided the seafloor into one-million-year old groupings, constructing a record back to 100 million years ago. At about 66 million years, he found evidence for a "short-lived pulse of marine magmatism" along ancient ocean ridges. This pulse is suggested by a spike in the rate of the occurrence of free-air gravity anomalies seen in the dataset.

Free-air gravity anomalies, measured in milligals, account for variations in gravitational acceleration, found from satellite measurements of additional seawater collecting where the Earth's gravity is stronger.

Excess matter on the ocean floor, such as new magma, is a primary cause of elevated marine gravity anomalies. A gal reflects a change in the rate of motion of a centimeter, about 0.4 of an inch, per second squared. Byrnes and Karlstrom found changes in free-air gravity anomalies of between five and 20 milligals associated with seafloor created in the first million years after the meteor.

"We found evidence for a previously unknown period of globally heighted volcanic activity during the mass-extinction event," Byrnes said. "This study does not say precisely that this volcanic activity is what killed the dinosaurs. What we are adding to the conversation is global volcanic activity during the known environmental crisis."

The gravity data analyzed in the research came from the Scripps Institution of Oceanography at the University of California, San Diego, the seafloor ages from the EarthByte group at the University of Sydney, and seafloor elevation from the National Geophysical Data Center of the National Oceanic and Atmospheric Administration.

Source: University of Oregon [February 07, 2018]

The migration of the dinosaurs across the globe was so rapid that it may have contributed to their demise, new research has found.

Credit: J Scott Applewhite/AP

A study by University of Reading scientists for the first time reveals the paths taken by the dinosaurs as they expanded out of South America during their rise to world dominance. The research shows that the speed of this expansion meant that the dinosaurs quickly became cosmopolitan and subsequently ran out of land. This lack of space then seriously impeded their ability to produce new species.

The work, published in Nature Ecology and Evolution, links to a previous Reading study that revealed the dinosaurs were in decline as a species 50 million years before the asteroid strike that finally wiped them out.

Ciara O'Donovan, evolutionary biologist at the University of Reading and lead author of the study, said: "Fossil evidence has shown us where the dinosaurs started out and where they died, but there is an important middle period that little was known about. Our research fills this gap in prehistory by revealing how the dinosaurs spread, how fast they moved and what directions they moved in through time.

"The dinosaurs exploded out of South America in a frenzy of movement to cover the planet. It was during this time that diverse forms evolved and eventually led to species such as the fearsome Tyrannosaurus rex, Archaeopteryx (the earliest bird) and the gigantic, long necked Diplodocus. This honeymoon period could not last forever though, and the dinosaurs eventually filled every available habitat on Earth.

"There was nowhere new for species to move to, which may have prevented new species from arising, contributing to the dinosaurs' pre-asteroid decline. In essence, they were perhaps too successful for their own good."

'Blank Canvas'

Fossil evidence shows dinosaurs originated in the late Triassic Period (around 230 million years ago) in South America, which was then part of the huge land mass called Pangea. This closely followed the world's largest extinction event that wiped out almost all of life on Earth.

The scientists developed a novel, statistical method to uncover where every dinosaur species' ancestors existed, in three dimensional space, on the globe. By doing this they were able to demonstrate that the dinosaurs spread unchecked across the huge available space, at a rate of 1,000km/million years. They dominated every terrestrial habitat, across all the continents as they drifted apart, over the course of 170 million years.

This saturation of the Earth caused the dinosaurs to become increasingly specialised to live in their existing environment, resulting in a fundamental change in the way they evolved and produced new species. This curbed their progress and left them vulnerable to future changes in the environment, such as those caused by the asteroid strike.

Dr. Chris Venditti, evolutionary biologist at the University of Reading and co-author of the paper, said: "Early dinosaurs had a blank canvas and spread quickly across the devastated Earth, taking up every opportunity in their path. Virtually every door was open to them as there was no competition from other species.

"The inability of the dinosaurs to adapt rapidly enough as the Earth became full may explain why they were in decline prior to the asteroid strike, and why they were so susceptible to almost total extinction when it hit."

Source: University of Reading [February 06, 2018]

A slab of sandstone discovered at NASA's Goddard Space Flight Center contains at least 70 mammal and dinosaur tracks from more than 100 million years ago, according to a new paper published in the journal Scientific Reports. The find provides a rare glimpse of mammals and dinosaurs interacting.

Detail view of a cast from the sandstone slab imprinted with more than 70 dinosaur and mammal tracks discovered at NASA's Goddard Space Flight Center in Greenbelt, Maryland [Credit: NASA's Goddard Space Flight Center/Rebecca Roth]

The tracks were discovered by Ray Stanford -- a local dinosaur track expert whose wife, Sheila, works at Goddard. After dropping off Sheila at work one day in 2012, Stanford spotted an intriguing rock outcropping behind Shelia's building on a hillside. Stanford parked his car, investigated, and found a 12-inch-wide dinosaur track on the exposed rock. Excavation revealed that the slab was the size of a dining room table and examination in the ensuing years found that it was covered in preserved tracks.

The remarkable Goddard specimen, about 8 feet by 3 feet in size, is imprinted with nearly 70 tracks from eight species, including squirrel-sized mammals and tank-sized dinosaurs. Analysis suggests that all of the tracks were likely made within a few days of each other at a location that might have been the edge of a wetland, and could even capture the footprints of predator and prey.

"The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world," said Martin Lockley, paleontologist with the University of Colorado, Denver, a co-author on the new paper. Lockley began studying footprints in the 1980s, and was one of the first to do so. "I don't think I've ever seen a slab this size, which is a couple of square meters, where you have over 70 footprints of so many different types. This is the mother lode of Cretaceous mammal tracks."

After Stanford's initial find, Stephen J. Godfrey, curator of paleontology at the Calvert Marine Museum, coordinated the excavation of the slab and produced the mold and cast that formed the basis of the scientific work.

Detail view of a cast from the sandstone slab imprinted with more than 70 dinosaur and mammal tracks discovered at NASA's Goddard Space Flight Center in Greenbelt, Maryland [Credit: NASA's Goddard Space Flight Center/Rebecca Roth]

The first track Stanford found was of a nodosaur -- "think of them as a four-footed tank," Stanford said. Subsequent examination revealed a baby nodosaur print beside and within the adult print, likely indicating that they were traveling together. The other dinosaur tracks include: a sauropod, or long-necked plant-eater; small theropods, crow-sized carnivorous dinosaurs closely related to the Velociraptor and Tyrannosaurus rex; and pterosaurs, a group of flying reptiles that included pterodactyls.

"It's a time machine," Stanford said. "We can look across a few days of activity of these animals and we can picture it. We see the interaction of how they pass in relation to each other. This enables us to look deeply into ancient times on Earth. It's just tremendously exciting."

The dinosaur tracks are impressive, but it is the collection of mammal tracks that make the slab significant. At least 26 mammal tracks have been identified on the slab since the 2012 discovery -- making it one of two known sites in the world with such a concentration of prints. Furthermore, the slab also contains the largest mammal track ever discovered from the Cretaceous. It is about four inches square, or the size of a raccoon's prints.

Lockley and Stanford said most of these ancient footprints belong to what we would consider small mammals -- animals the size of squirrels or prairie dogs. Most Cretaceous mammals discovered to date have been the size of rodents, their size usually determined only from their teeth. "When you have only teeth, you have no idea what the animals looked like or how they behaved," Lockley said.


Lockley and Stanford believe the wide diversity and number of tracks show many of the animals were in the area actively feeding at the same time. Perhaps the mammals were feeding on worms and grubs, the small carnivorous dinosaurs were after the mammals, and the pterosaurs could have been hunting both the mammals and the small dinosaurs.

The parallel trackway patterns made by four crow-sized carnivorous dinosaurs suggests they were hunting or foraging as a group. "It looks as if they were making a sweep across the area," Lockley said.

Several of the mammal tracks occur in pairs, representing hind feet. "It looks as if these squirrel-sized animals paused to sit on their haunches," Lockley said. The team gave the new formal scientific name of Sederipes goddardensis, meaning sitting traces from Goddard Space Flight Center, to this unusual configuration of tracks.

"We do not see overlapping tracks -- overlapping tracks would occur if multiple tracks were made over a longer period while the sand was wet," said Compton Tucker, a Goddard Earth scientist who helped with the excavation, coordinated bringing in multiple scientists to study the tracks, and has worked to create a display of the cast in Goddard's Earth science building. "People ask me, 'Why were all these tracks in Maryland?' I reply that Maryland has always been a desirable place to live."

What is now Maryland would have been a much hotter, swampier place in the Cretaceous, when sea levels would have been hundreds of feet higher than today. As scientists continue to study the slab and compare the tracks to others found in the area and around the world, they will continue to discover more about prehistoric life that existed here.

"This could be the key to understanding some of the smaller finds from the area, so it brings everything together," Lockley said. "This is the Cretaceous equivalent of the Rosetta stone."

Author: Ashley Hume and Patrick Lynch | Source: NASA/Goddard Space Flight Center [January 31, 2018]

When it comes to the final days of the dinosaurs, Africa is something of a blank page. Fossils found in Africa from the Late Cretaceous, the time period from 100 to 66 million years ago, are few and far between. That means that the course of dinosaur evolution in Africa has largely remained a mystery. But in the Sahara Desert of Egypt, scientists have discovered a new species of dinosaur that helps fill in those gaps: Mansourasaurus shahinae, a school-bus-length, long-necked plant-eater with bony plates embedded in its skin.

Life reconstruction of the new titanosaurian dinosaur Mansourasaurus shahinae on a coastline in what is now the Western  Desert of Egypt approximately 80 million years ago [Credit: Andrew McAfee, Carnegie Museum of Natural History]

The fossilized remains of Mansourasaurus were unearthed by an expedition undertaken by the Mansoura University Vertebrate Paleontology (MUVP) initiative, an effort led by Dr. Hesham Sallam of the Department of Geology at Mansoura University in Mansoura, Egypt. Sallam is the lead author of the paper published today in the journal Nature Ecology and Evolution that names the new species. The field team included several of his students, many of whom -- Ms. Iman El-Dawoudi, Ms. Sanaa El-Sayed, and Mrs. Sara Saber -- also participated in the study of the new dinosaur. The creature's name honors both Mansoura University and Ms. Mona Shahin for her integral role in developing the MUVP. According to Sallam, "The discovery and extraction of Mansourasaurus was such an amazing experience for the MUVP team. It was thrilling for my students to uncover bone after bone, as each new element we recovered helped to reveal who this giant dinosaur was."

"Mansourasaurus shahinae is a key new dinosaur species, and a critical discovery for Egyptian and African paleontology," says Dr. Eric Gorscak, a postdoctoral research scientist at The Field Museum and a contributing author on the study. Gorscak, who began work on the project as a doctoral student at Ohio University, where his research focused on African dinosaurs, adds, "Africa remains a giant question mark in terms of land-dwelling animals at the end of the Age of Dinosaurs. Mansourasaurus helps us address longstanding questions about Africa's fossil record and paleobiology -- what animals were living there, and to what other species were these animals most closely related?"

Skeletal reconstruction of the new titanosaurian dinosaur Mansourasaurus shahinae from the Late Cretaceous of the Dakhla  Oasis, Egypt. Bones shown in color are those that are preserved in the original fossil; other bones are based on those of  closely related dinosaurs [Credit: Andrew McAfee, Carnegie Museum of Natural History]

Late Cretaceous dinosaur fossils in Africa are hard to come by -- much of the land where their fossils might be found is covered in lush vegetation, rather than the exposed rock of dinosaur treasure troves such as those in the Rocky Mountain region, the Gobi Desert, or Patagonia. The lack of a Late Cretaceous fossil record in Africa is frustrating for paleontologists since, at that time, the continents were undergoing massive geological and geographic changes.

During the earlier years of the dinosaurs, throughout much of the Triassic and Jurassic periods, all the continents were joined together as the supercontinent of Pangaea. During the Cretaceous Period, however, the continents began splitting apart and shifting towards the configuration we see today. Historically, it hasn't been clear how well-connected Africa was to other Southern Hemisphere landmasses and Europe during this time -- to what degree Africa's animals may have been cut off from their neighbors and evolving on their own separate tracks. Mansourasaurus, as one of the few African dinosaurs known from this time period, helps to answer that question. By analyzing features of its bones, Sallam and his team determined that Mansourasaurus is more closely related to dinosaurs from Europe and Asia than it is to those found farther south in Africa or in South America. This, in turn, shows that at least some dinosaurs could move between Africa and Europe near the end of these animals' reign. "Africa's last dinosaurs weren't completely isolated, contrary to what some have proposed in the past," says Gorscak. "There were still connections to Europe."

Mansourasaurus belongs to the Titanosauria, a group of sauropods (long-necked plant-eating dinosaurs) that were common throughout much of the world during the Cretaceous. Titanosaurs are famous for including the largest land animals known to science, such as Argentinosaurus, Dreadnoughtus, and Patagotitan. Mansourasaurus, however, was moderate-sized for a titanosaur, roughly the weight of an African bull elephant. Its skeleton is important in being the most complete dinosaur specimen so far discovered from the end of the Cretaceous in Africa, preserving parts of the skull, the lower jaw, neck and back vertebrae, ribs, most of the shoulder and forelimb, part of the hind foot, and pieces of dermal plates. Says study coauthor and dinosaur paleontologist Dr. Matt Lamanna of Carnegie Museum of Natural History, "When I first saw pics of the fossils, my jaw hit the floor. This was the Holy Grail -- a well-preserved dinosaur from the end of the Age of Dinosaurs in Africa -- that we paleontologists had been searching for for a long, long time."

The left dentary, or lower jaw bone, of the new titanosaurian dinosaur Mansourasaurus shahinae as it was found in rock  of the Upper Cretaceous-aged (~80 million-year-old) Quseir Formation of the Dakhla Oasis, Egypt  [Credit: Hesham Sallam, Mansoura University]

Also contributing to the Mansourasaurus research were experts on African paleontology from other institutions in Egypt and the US. MUVP student Iman El-Dawoudi played a particularly important role in the analysis of the new titanosaur, making numerous observations on its skeleton. "The combined effort of multiple institutions across the globe, not to mention the absolutely key role played by students on the project from the field, to the laboratory, to the final analysis and writeup of the results, exemplifies the collaborative nature of expeditionary sciences today," notes Dr. Patrick O'Connor, study coauthor and professor of anatomy at the Ohio University Heritage College of Osteopathic Medicine.

Funding for the Mansourasaurus study was provided by grants from Mansoura University, the Jurassic Foundation, the Leakey Foundation, the National Geographic Society/Waitt Foundation, and the National Science Foundation (NSF).

"The discovery of rare fossils like this sauropod dinosaur helps us understand how creatures moved across continents, and gives us a greater understanding of the evolutionary history of organisms in this region," says Dena Smith, a program director in NSF's Division of Earth Sciences, which partially funded the laboratory portion of the research.

Scientific discoveries are often compared to finding the last missing puzzle piece to complete a picture; Gorscak says that since so little is known about African dinosaurs, Mansourasaurus is better likened to an earlier step in the puzzle-solving process. "It's like finding an edge piece that you use to help figure out what the picture is, that you can build from. Maybe even a corner piece."

"What's exciting is that our team is just getting started. Now that we have a group of well-trained vertebrate paleontologists here in Egypt, with easy access to important fossil sites, we expect the pace of discovery to accelerate in the years to come," says Sallam.

Source: Ohio University [January 29, 2018]

Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich report the first description of the geologically oldest fossil securely attributable to the genus Archaeopteryx, and provide a new diagnostic key for differentiating bird-like dinosaurs from their closest relatives.

The geologically oldest, but most recently discovered specimen of Archaeopteryx [Credit: O. Rauhut, LMU Munich]

Some 150 million years ago in what is now Northern Bavaria, Archaeopteryx, the oldest bird species ever discovered, inhabited a subtropical environment characterized by reef islands and lagoons set in a shallow sea that was part of the primordial Mediterranean. All the specimens of Archaeopteryx so far recovered were found in the valley of the Altmühl River, in geological settings that represent this habitat—the Jurassic Solnhofen Archipelago. The latest find was made there in 2010, and this new specimen has now been analyzed by a team of researchers led by LMU paleontologist Oliver Rauhut, a professor in the Department of Earth and Environmental Sciences who is also affiliated with the Bavarian State Collections for Paleontology and Geology in Munich. Stratigraphic analysis of the find locality reveals that the fossil is the oldest known representative of the genus Archaeopteryx.

"Specimens of Archaeopteryx are now known from three distinct rock units, which together cover a period of approximately 1 million years," Rauhut explains. Notably, the oldest example exhibits features that were not observed in the other specimens. "Among other things, they reveal that Archaeopteryx was very similar to advanced predatory dinosaurs in many respects," says Rauhut. Moreover, in the new study, he and his colleagues provide a diagnosis that reliably distinguishes Archaeopteryx from its closest relatives, both non-avialan theropod dinosaurs and basal birds. This key will be very valuable, as a whole series of bird-like predatory dinosaurs has been described in recent years, mainly from China, which has greatly complicated the taxonomic classification of the group.

The new specimen is the 12th fossil to be attributed to the genus. However, in a study published in the online journal BMC Evolutionary Biology last year, Rauhut's group reported that the first of these to come to light—the so-called Haarlem specimen discovered in 1861—does not actually belong to the group. This result thus reduces the number of Archaeopteryx fossils to 11, although some doubts remain concerning the assignment of two of these. This underlines the necessity for a diagnosis to clearly identify Archaeopteryx.

Moreover, the investigation of the 11th specimen demonstrates that the known specimens span a remarkable range of anatomical variation. Potential explanations for the broad spectrum of variation extend from intraspecific developmental polymorphism to evolutionary differentiation, i.e., the possibility that the fossil material so far recovered represents more than one species. "The high degree of variation in the teeth is particularly striking—none of the specimens shows the same pattern of dentition as any other, which could reflect differences in diet," Rauhut says. "This is very reminiscent of the famous case of Darwin's finks on the Galapagos, which show remarkable variation in their beak shapes. It is even conceivable that this primeval bird genus might, in a similar fashion, have diversified into several specialized forms on the islands of the Solnhofener Archipelago. In that case, the Archaeopteryx fossils could represent a species flock, a Jurassic analog of Darwin's finches."

Source: Ludwig Maximilian University of Munich [January 26, 2018]

Dinosaurs that lived in what is now known as Victoria more than 120 million years ago would have dealt with prolonged periods of darkness and below freezing temperatures, a new study reveals.

The fossil bone tissue reveals new information about how the Australian “hypsilophodontid” dinosaurs lived [Credit: Peter Trusler]

The study, published in the Scientific Reports journal, examines the bone tissue microstructure of plant-eating "hypsilophodontid" dinosaurs known to have lived in the Antarctic Circle—now Victoria, Australia.

"These little dinosaurs would have dealt with prolonged periods of darkness and mean annual temperatures near freezing, and certainly below freezing in the winter," says one of the study authors, Dr. Patricia Vickers-Rich, a professor of paleobiology at Swinburne.

In studying fossils from seventeen individuals, the International research team from Swinburne University of Technology, Oklahoma State University, Museums Victoria, and Monash University produced the first life history reconstructions for these small Australian polar dinosaurs.

Examining bone microstructure

An examination of the bone microstructure, or histology, of the hypsilophodontid fossils revealed many characteristics of their growth.

Rings in the bone, similar in appearance to tree rings, helped determine individual age. Bone fibre orientation, blood vessel density, and the amount of bone between growth rings, was used to determine annual growth rates.

Bone histology revealed that, in general, growth was most rapid during the first three years of life, and the dinosaurs were fully grown – the size of a medium wallaby or average turkey—in five to seven years.

Uncovering Australia's past

The hypsilophodontid samples were recovered from two Australian localities along the south Victorian coast stretching from west of Cape Otway to Inverloch, geologically separated by about 12 million years.

However, the trend of rapid growth for three years followed by adult body size between five and seven years, was conserved across the two samples.

"Given the geologic time involved, we may be looking at several polar dinosaur species in this sample, but their growth trajectories are so similar that we cannot differentiate them from one another based on their growth patterns and rates alone," says Holly Woodward (Oklahoma State University).

"Instead, our life history assessment demonstrates to us that this generalised growth trajectory was a successful lifestyle for surviving in a region experiencing unique conditions."

Histologic examinations

The tibia (shin-bone) of one hypsilophodontid individual in the sample had clearly suffered from a pathologic condition known as osteomyelitis or bone infection.

Microscopic examination revealed the cause of this pathology was most likely a broken bone, which then became infected. Counting the growth rings preserved in this tibia prior to the formation of the pathologic bone, the team was able to place the timing of the injury as having occurred when this individual was approximately four years old.

The team was also able to tease out how long this little dinosaur lived and how it dealt with the injury: histologic examination of the unaffected femur (thigh bone) of this individual shows that it survived with the injury and pathology for three more years.

"Further investigations of this unique sample will continue to shed light on how these little dinosaurs thrived in high latitudes and under the most stressful of environments during a time when dinosaurs flourished on planet Earth," Dr. Vickers-Rich says.

Source: Swinburne University of Technology [January 24, 2018]

We're all familiar with those awesome armored giants of the Jurassic and Cretaceous periods - Stegosaurus and Ankylosaurus - and their amazing, weaponized tails. But why aren't similar weaponized tails found in animals living today? In a study covering 300 million years of evolutionary history, researchers from North Carolina State University and the North Carolina Museum of Natural Sciences found four necessary components to tail weapon development: size, armor, herbivory and thoracic stiffness.

Two Ankylosaurus exchange blows using their tail clubs [Credit: Jack Mayer Wood]

"Weapons like tail clubs and bony spikes are found only in a few extinct animals - such as ankylosaurs, glyptodonts (large extinct armadillos) and in some ancient turtle species," says Victoria Arbour, former postdoctoral student at NC State, current postdoctoral fellow at the Royal Ontario Museum and corresponding author of a paper describing the research. "These same weapons just don't occur in modern-day animals, and we wanted to know why they were so rare even in the fossil record."

Study co-author Lindsay Zanno, professor of biological sciences at NC State and head of paleontology at the NC Museum of Natural Sciences, agrees, "We kicked off this study with a simple observation: most animal weapons used for combat are located on the most critical part of the body for survival, the head, as opposed to more expendable ones such as the tail. Why, we asked, wasn't evolution producing more animals with weaponized tails, when this would seem to be far less dangerous?"

To answer this question, Arbour and Zanno looked at a data set of 286 amniote species, both living and extinct, to see if there were patterns that pointed to the evolution of three specific types of tail weapons: bony spikes, a stiff tail or a bony knob at the tip of the tail. Amniotes refer to backboned, four-legged reptiles and mammals, as well as birds.

In the case of bony tail weaponry, the researchers found the animals had four things in common. First, they were usually large, weighing over 200 pounds (or 100 kilograms) - about the weight of the glyptodonts that used to roam South America or a living mountain goat - or were over three feet (a meter) long.

Second, armor was key. Ancient turtles, armadillos and armored dinosaurs were covered in some sort of hard carapace or bony plated armor. Thoracic stiffness - referring to a body that doesn't bend side to side easily, perhaps so that it could easily counteract the forces needed to swing a large clubbed or spiked tail - was also important. Finally, every animal in the fossil record that developed elaborate tail weaponry was an herbivore, or vegetarian.

"It's rare for large herbivores to have lots of bony armor to begin with," Arbour says, "and even rarer to see armored species with elaborate head or tail ornamentation because of the energy cost to the animal. The evolution of tail weaponry in Ankylosaurus and Stegosaurus required a 'perfect storm' of traits that aren't seen in living animals, and this unique combination explains why tail weaponry is rare even in the fossil record."

Zanno continues, "This study is an elegant example of how the fossil record can be used to better understand the world around us today."

The research appears in Proceedings of the Royal Society B.

Author: Tracey Peake | Source: North Carolina State University [January 17, 2018]

Scientists using laser-imaging technology have documented and digitally preserved the first known set of theropod dinosaur tracks in the state of Arkansas.

Tracks of Acrocanthosaurus atokensis [Credit: University of Arkansas]

The tracks, discovered in 2011 in a working gypsum quarry near Nashville, Ark., have since been destroyed. But high-resolution digital scans taken over a period of two weeks in 2011 allowed a team of researchers to study the tracks and determine that they were made by Acrocanthosaurus, a large, carnivorous dinosaur. The findings extended the known range of Acrocanthosaurus 56 miles east, to the western shore of an ancient inland sea.

"It actually confirms that the main genus of large theropods in North America was Acrocanthosaurus," said Celina Suarez, an assistant professor in the Department of Geosciences who was part of the team that documented and studied the tracks. "It now has been found in Wyoming, Utah, Oklahoma, Arkansas and Maryland, a huge range."

Results of the study were recently published in the journal PLOS ONE. Researchers also created a detailed, publicly accessible online map of the site and the tracks. Brian Platt, an assistant professor of geology from the University of Mississippi, led the study. Researchers from the University of Arkansas Center for Advanced Spatial Technology (CAST) provided the scanning equipment and expertise.

The Rush to Preserve the Site

After the tracks were discovered, researchers received a $10,000 Rapid Grant from the National Science Foundation to quickly document the site. The U of A's vice provost for research and economic development and the J. William Fulbright College of Arts and Sciences provided matching grants, for a total of $30,000.

University of Arkansas researchers used lift-mounted LiDAR equipment to preserve and study dinosaur tracks  [Credit: Russell Cothren]

The mining company moved its operations to allow researchers a short window of time to document the find. Researchers used LiDAR, which stands for light detection and ranging, because traditional methods would have taken too long, said Suarez. "From a technical standpoint, it's important that the ability to rapidly scan such a large area is available to paleontologists. It was invaluable for this project since we had such little time to work."

The site had two different sized Acrocanthosaurus tracks, suggesting both adult and younger animals walked the ancient tidal flat about 100 million years ago, during the Cretaceous Period. It also contained tracks made by sauropods, long-necked plant-eating dinosaurs.

LiDAR uses a pulsed laser to measure distances to the earth in tiny increments, generating a data "point cloud" that is used to digitally recreate a physical space. In this case, the equipment was mounted on a lift over the site. By analyzing carbon and oxygen isotopes of the rock at the track surface, researchers determined that the track surface was indeed the surface that the animals stepped on, rather than an underlying layer that remained when the original surface eroded.

The digital reconstruction of the trackway site: http://trackways.cast.uark.edu/index.html

Source: University of Arkansas, Fayetteville [January 16, 2018]

Birds are the last remaining dinosaurs. They're also some of the most vibrantly colored animals on Earth. A new study in Nature Communications reveals that iridescent feathers go way back--a newly discovered species of dinosaur from 161 million years ago had rainbow coloring.

Caihong juji is a newly described, bird-like dinosaur with an iridescent, rainbow crest. It lived in China about 161 million  years ago, and may have used its impressive feathers to attract mates. Illustration by Velizar Simeonovski, The Field  Museum, for UT Austin Jackson School of Geosciences [Credit: Velizar Simeonovski, The Field Museum]

Caihong juji was tiny, about the size of a duck, with a bony crest on its head and long, ribbon-like feathers. And, based on analysis of its fossilized feathers, the feathers on its head, wings, and tail were probably iridescent, with colors that shimmered and shifted in the light. Its name reflects its appearance--in Mandarin, it means, "rainbow with the big crest." The new species, which was first discovered by a farmer in northeastern China, was described by an international team of scientists led by Dongyu Hu, a professor in the College of Paleontology at the Shenyang Normal University in China.

"When you look at the fossil record, you normally only see hard parts like bone, but every once in a while, soft parts like feathers are preserved, and you get a glimpse into the past," says Chad Eliason, a postdoctoral researcher at The Field Museum and one of the study's authors. Eliason, who began work on the project as a postdoctoral fellow at the University of Texas at Austin, added, "The preservation of this dinosaur is incredible, we were really excited when we realized the level of detail we were able to see on the feathers."

When the scientists examined the feathers under powerful microscopes, they could see the imprints of melanosomes, the parts of cells that contain pigment. For the most part, the pigment that was once present was long gone, but the physical structure of the melanosomes remained. As it turns out, that was enough for scientists to be able to tell what color the feathers were.

This is a fossil skull of Caihong juji [Credit: Yu, et al., 2018]

That's because color isn't only determined by pigment, but by the structure of the melanosomes containing that pigment. Differently shaped melanosomes reflect light in different colors. "Hummingbirds have bright, iridescent feathers, but if you took a hummingbird feather and smashed it into tiny pieces, you'd only see black dust. The pigment in the feathers is black, but the shapes of the melanosomes that produce that pigment are what make the colors in hummingbird feathers that we see," explains Eliason.

The scientists were able to match the shapes of the pancake-shaped melanosomes in Caihong with the shapes of melanosomes in birds alive today. By finding birds with similarly shaped melanosomes, they were able to determine what kinds of colors Caihong may have flashed. The best matches: hummingbirds.

Colorful plumage is used in modern birds to attract mates--the rainbow feathers of Caihong might be a prehistoric version of a peacock's iridescent tail. Caihong is the oldest known example of platelet-shaped melanosomes typically found in bright iridescent feathers.

This is holotype fossil of Caihong juji, including line drawing of fossil skeleton  [Credit: Yu, et al., 2018]

It's also the earliest known animal with asymmetrical feathers--a feature used by modern birds to steer when flying. Caihong couldn't fly, though--its feathers were probably primarily used to attract mates and keep warm. While modern birds' asymmetrical feathers are on their wingtips, Caihong's were on its tail. "The tail feathers are asymmetrical but wing feathers not, a bizarre feature previously unknown among dinosaurs including birds," said co-author Xing Xu of the Chinese Academy of Science. "This suggests that controlling [flight] might have been first evolved with tail feathers during some kind of aerial locomotion."

But while Caihong's feathers were a first, it had other traits associated with much earlier species of dinosaurs, including the bony crest on its head. "This combination of traits is rather unusual," says co-author Julia Clarke of the University of Texas at Austin. "It has a velociraptor-type skull on the body of this very avian, fully feathered, fluffy kind of form."

This combination of old and new traits, says Eliason, is evidence of mosaic evolution, the concept of different traits evolving independently from each other. "This discovery gives us insight into the tempo of how fast these features were evolving," he adds.

For Eliason, the study also illuminates the value of big data. "To find the color of Caihong's feathers, we compared its melanosomes with a growing database of thousands of measurements of melanosomes found in modern birds," he says. It's also broadened his own research interests.

"I came out of the project with a whole different set of questions that I wanted answers to--when I open up a drawer full of birds in the Field Museum's collections, now I want to know when those iridescent feathers first developed, and how."

Source: Field Museum [January 16, 2018]

Geobios has published an article by researchers from TSU, St. Petersburg State University, and the Zoological Institute of the Russian Academy of Sciences describing a new genus and type of dinosaurs. The remains of a fossil animal belonging to the taxon of the largest herbivorous lizards – sauropod – were discovered by scientists during an expedition in 2008. In the process of studying the fossils, paleontologists found anatomical features that distinguish this dinosaur from other well-known dinosaurs. The new genus was named Sibirotitan, and the species is Sibirotitan astrosacralis.

Credit: © tsu.ru

The remains of the giant animal were found in the Shestakovo 1 locality (Kemerovo Region, Western Siberia, Russia), which includes some of the largest sites of the dinosaur and mammoth fauna in Russia. The bone fragments were buried in the dense sandstone of the Ileks suite, and it took the researchers several years of laboratory work to extract them from the clumps of cemented rock. As a result, almost a whole sacrum was assembled from some parts, and part of a scapula and cervical vertebrae were assembled from numerous other pieces.

Credit: © tsu.ru

"The new kind of dinosaur is described by several isolated vertebrae, which most likely belong to one individual. In addition, the foot fragment described in 2002 refers to it. With Professor Alexander Averyanov from the Zoological Institute of the Russian Academy of Sciences working in our laboratory, we conducted a comparative analysis of the remains with sauropods found in other countries. It turned out that our lizard has anatomical features that distinguish it from all known brethren," says Stepan Ivantsov, a researcher at the TSU’s Laboratory of Mesozoic and Cenozoic Continental Ecosystems.

Credit: © tsu.ru

A characteristic feature of the new genus is the presence of five sacral vertebrae, sacral ribs oriented radially (in the form of a star), and a special crest on the neural arc of the trunk vertebra. Ancient lizards with such a skeletal structure have never been found anywhere.

Credit: © tsu.ru

Anatomical features and binding to the former habitat are recorded in the Latin name of the new species - Sibirotitan astrosacralis. The first part of the name indicates the giant size of a dinosaur, who cold have been 20 meters long and weighed 50 tons.

Until recently, only one Russian find of dinosaur bones from the Sauropod taxon was known. Several vertebrae of the ancient animal were found in Transbaikalia. At the moment, Sibirotitan, whose age is about 100 million years, is the second sauropod described in Russia and the oldest representative of titanosauriforms in Asia.


And unlike paleontological finds that are kept in museums of other Russian universities, TSU installed a unique exhibit in a place of free access –in the hall of the Center of Culture, where it is accessible to the maximum number of people.

Titanosauriforms are included in a taxon of herbivorous dinosaurs-sauropods, who lived in the Jurassic and Cretaceous periods on the territory of all modern continents. The largest specimens could reach a length of 35-40 meters and weigh up to 100 tons. At the same time, they had fairly small teeth (4-6 cm), which were used to tear off leaves.

Source: Tomsk State University [January 13, 2018]