South American fossil tomatillos show nightshades evolved earlier than thought

Delicate fossil remains of tomatillos found in Patagonia, Argentina, show that this branch of the economically important family that also includes potatoes, peppers, tobacco, petunias and tomatoes existed 52 million years ago, long before the dates previously ascribed to these species, according to an international team of scientists.

Tomatillos, ground cherries and husk tomatoes — members of the physalis genus — are unusual because they have papery, lantern-like husks, known to botanists as inflated calyces that grow after fertilization to extend around their fleshy, often edible berries. They are a small portion of the nightshade family, which includes many commercially, scientifically and culturally valuable plants among its more than 2,400 living species. This entire family has had a notably poor fossil record, limited to tiny seeds and wood with little diagnostic value that drastically limited understanding of when and where it evolved.

The researchers examined two fossil lantern fruit collected at Laguna del Hunco, Chubut, Patagonia, Argentina, in an area that was temperate rainforest when the plants grew, 52 million years ago. These are the only physalis fossils found among more than 6,000 fossils collected from this remote area, and they preserve very delicate features such as the papery husk and the berry itself. The fossil site, which has been the focus of a Penn State, Museo Palentologico Egidio Feruglio, Trelew, Argentina, and Cornell University project for more than a decade, was part of terminal Gondwana, comprised of the adjacent landmasses of South America, Antarctica and Australia during a warm period of Earth history, just before their final separation.

“These astonishing, extremely rare specimens of physalis fruits are the only two fossils known of the entire nightshade family that preserve enough information to be assigned to a genus within the family,” said Peter Wilf, professor of geosciences, Penn State. “We exhaustively analyzed every detail of these fossils in comparison with all potential living relatives and there is no question that they represent the world’s first physalis fossils and the first fossil fruits of the nightshade family. Physalis sits near the tips of the nightshade family’s evolutionary tree, meaning that the nightshades as a whole, contrary to what was thought, are far older than 52 million years.”

Typically, researchers look for fossilized fruits or flowers as their first choice in identifying ancient plants. Because the fruits of the nightshade family are very delicate and largely come from herbaceous plants with low biomass, they have little potential to fossilize. The leaves and flowers are also unknown from the fossil record. This presents a problem for understanding when and where the group evolved and limits the use of fossils to calibrate molecular divergence dating of these plants.

Molecular dating of family trees relies on actual dates of fossils in the family to work from. Because the previous dated fossils had little diagnostic value beyond their membership in the large nightshade family, molecular dating was difficult.

The researchers note in Science that “The fossils are significantly older than corresponding molecular divergence dates and demonstrate an ancient history for the inflated calyx syndrome.”

Molecular dates calibrated with previous fossils had placed the entire nightshade family at 35 to 51 million year ago and the tomatillo group, to which the 52 million year old fossils belong, at only 9 to 11 million years ago.

Using direct geologic dating of materials found with the fossils — argon-argon dating of volcanic tuffs and recognition of two magnetic reversals of the Earth’s poles — the team had previously dated the rocks containing the fossil fruit to 52 million years ago.

“Paleobotanical discoveries in Patagonia are probably destined to revolutionize some traditional views on the origin and evolution of the plant kingdom,” said N. Rubén Cúneo, CONICET, Museo Palentológico Egidio Feruglio. “In this regard, the Penn State/ MEF/Cornell scientific partnership is showing the strength of international collaborations to bring light and new challenges to the exciting world of discovering the secrets of Earth life.”

Mónica Carvalho, former Penn State M.S. student now a Ph.D. student at the School of Integrative Plant Science, Cornell, and Wilf did the evolutionary analysis of the morphology of current members of the family and the fossils, combined with genetic analysis of the living species.

“These fossils are one of a kind, since the delicate papery covers of lantern fruits are rarely preserved as fossils,” Carvalho said. “Our fossils show that the evolutionary history of this plant family is much older than previously considered, particularly in South America, and they unveil important implications for understanding the diversification of the family.”

All members of the physalis genus are New World species inhabiting South, Central and North America. Their center of diversity is Mexico.

The researchers note that the physalis fossils show a rare link from late-Gondwanan Patagonian to living New World plants, but most other fossil plants, such as eucalyptus, found at the site have living relatives concentrated in Australasia. That pattern reflects the ancient overland connection across terminal Gondwana from South America to Australia through Antarctica. The new research raises the possibility that more, potentially much older, nightshade fossils may be found at far southern locations.

“Our results reinforce the emerging pattern wherein numerous fossil plant taxa from Gondwanan Patagonia and Antarctica are substantially older than their corresponding molecular dates, demonstrating Gondwanan history to groups conjectured to have post-Gondwanan origins under entirely different paleogeographic and paleoclimatic scenarios,” the researchers wrote.

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Materials provided by Penn State. Original written by A’ndrea Elyse Messer. Note: Content may be edited for style and length.

Rare leafcutter bee fossils reveal Ice Age environment at the La Brea Tar Pits

Concerns about climate change and its impact on the world around us are growing daily. New scientific studies at the La Brea Tar Pits are probing the link between climate warming and the evolution of Ice Age predators, attempting to predict how animals will respond to climate change today.

The La Brea Tar Pits are famous for the amazing array of Ice Age fossils found there, such as ground sloths, mammoths, and predators like saber-toothed cats and powerful dire wolves. But the climate during the end of the Ice Age (50,000-11,000 years ago) was unstable, with rapid warming and cooling. New research reported here has documented the impact of this climate change on La Brea predators for the first time.

Two new studies published by research associates at of the Page Museum document significant change over time in the skulls of both dire wolves and saber-toothed cats. “Different tar pits at La Brea accumulated at different times,” said F. Robin O’Keefe of Marshall University, lead author on the dire wolf study. “When we compare fossils deposited at different times, we see big changes. We can actually watch evolution happening.”
After the end of the last Ice Age, La Brea dire wolves became smaller and more graceful, adapting to take smaller prey as glaciers receded and climate warmed. This rapidly changing climate drove change in saber-toothed cats as well. “Saber-toothed cats show a clear correlation between climate and shape. Cats living after the end of the Ice Age are larger, and adapted to taking larger prey,” said Julie Meachen of Des Moines University, lead author on the sabertooth study.
The two scientists discuss their work in a video here:
“We can see animals adapting to a warming climate at La Brea,” said O’Keefe. “Then humans show up and all the big ones disappear. We haven’t been able to establish causality there yet. But we are working on it.”
The emerging links between climate change and evolution needs further study. There are many unanswered questions; such as why predators change in the ways that they do, the importance of factors other than climate, and whether the arrival of humans played a role in the mass extinction at the end of the Ice Age. “There is much work to be done on the specimens from the tar pits. We are working actively to bring together the researchers and resources needed to expand on these discoveries,” says John Harris, chief curator at the Page Museum. “Climate change is a pressing issue for all of us, and we must take advantage of what Rancho La Brea can teach us about how ecosystems react to it.”

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.

‘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.

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.”

Tooth Is ‘Smoking Gun’ Evidence That Tyrannosaurus Rex Was Hunter, Killer

July 16, 2013 — Tyrannosaurus rex has long been popular with kids and moviemakers as the most notorious, vicious killing machine to roam the planet during the age of the dinosaurs.


So, it may come as a shock that for more than a century some paleontologists have argued that T. rex was a scavenger, not a true predator — more like a vulture than a lion. Indeed, a lack of definitive fossil proof of predation in the famous theropod has stirred controversy among scientists — until now.

“T. rex is the monster of our dreams,” said David Burnham, preparator of vertebrate paleontology at the Biodiversity Institute at the University of Kansas. “But ever since it was discovered in Montana and named in the early 1900s, there’s been a debate about whether these large carnivores were scavengers or predators. Most people assume they were predators, but the scientific evidence for predation has been really elusive. Yes, we’ve found lots of dinosaur skeletons with tooth marks that had been chewed up by something. But what did that really prove? Yes, these large carnivores fed on other dinosaurs — but did they eat them while they were alive or dead? That’s where the debate came in. Where was the evidence for hunt and kill?”

Now, Burnham is part of a team that has unearthed “smoking gun” physical proof that T. rex was indeed a predator, hunter and killer. In the Hell Creek Formation of South Dakota, Burnham and colleagues discovered the crown of a T. rex tooth lodged in the fossilized spine of a plant-eating hadrosaur that seems to have survived the attack. The team describes the find in the current issue of the Proceedings of the National Academy of Sciences.

Burnham’s KU co-authors are Bruce Rothschild and the late Larry Martin, along with former KU student Robert DePalma II of The Palm Beach Museum of Natural History and Peter Larson of the Black Hills Institute of Geological Research.

“Robert DePalma was a student here at KU doing his master’s thesis in the Hell Creek formation,” said Burnham. “He found a specimen that represents the tail of one of these hadrosaurs. It had a distorted-looking bone growth. He came to me and said, ‘What do you think is causing this?’ So we cleaned it and could see a tooth embedded in one of these duck-billed dinosaur vertebrae. Then we went to Lawrence Memorial Hospital and used a CT machine to scan the bones — and we saw all of the tooth.”

Previous evidence for predation included T. rex fossil discoveries with preserved stomach contents that included the bones of a young ceratopsian (e.g., Triceratops or one of its kin). However, there was no evidence to conclude whether the ceratopsian was alive or dead when the T. rex made a snack of it.

By contrast, Burnham said the tooth was definitive evidence of hunting, after carefully measuring its length and the size of its serrations to ensure that it came from the mouth of a T. rex.

“Lo and behold, the tooth plotted out just exactly with T. rex — the only known large theropod from the Hell Creek formation,” he said. “We knew we had a T. rex tooth in the tail of a hadrosaur. Better yet, we knew the hadrosaur got away because the bone had begun to heal. Quite possibly it was being pursued by the T. rex when it was bitten. It was going in the right direction — away. The hadrosaur escaped by some stroke of luck. The better luck is finding this fossil with the preserved evidence.”

Because T. rex regularly shed its teeth, the predator went away hungry, but otherwise no worse for the encounter. It would have grown a new tooth to replace the one left behind in the hadrosaur’s tail. This could have been a typical example of T. rex’s hunting efforts, even if it didn’t result in a meal.

“To make an analogy to modern animals, when lions go attack a herd of herbivores, they go after the sick and the slow,” Burnham said. “Most of the time, hadrosaurs traveled in packs. This hadrosaur may have been a little slower, or this T. rex may have been a little faster — at least fast enough to almost catch a duck-billed dinosaur.”

This concrete proof of T. rex’s predation continues a long relationship between KU paleontologists and the theropod, which lived in North America during the Late Cretaceous, some 65 million years ago. KU graduate Barnum Brown discovered the first documented remains of the dinosaur in Wyoming in 1900.

Fossil Saved from Mule Track Revolutionizes Understanding of Ancient Dolphin-Like Marine Reptile

May 14, 2013 — An international team of scientists have revealed a new species of ichthyosaur (a dolphin-like marine reptile from the age of dinosaurs) from Iraq, which revolutionises our understanding of the evolution and extinction of these ancient marine reptiles.
The results, produced by a collaboration of researchers from universities and museums in Belgium and the UK and published today (May 15) in Biology Letters, contradict previous theories that suggest the ichthyosaurs of the Cretaceous period (the span of time between 145 and 66 million years ago) were the last survivors of a group on the decline.

Ichthyosaurs are marine reptiles known from hundreds of fossils from the time of the dinosaurs. “They ranged in size from less than one to over 20 metres in length. All gave birth to live young at sea, and some were fast-swimming, deep-diving animals with enormous eyeballs and a so-called warm-blooded physiology,” says lead author Dr Valentin Fischer of the University of Liege in Belgium.

Until recently, it was thought that ichthyosaurs declined gradually in diversity through multiple extinction events during the Jurassic period. These successive events were thought to have killed off all ichthyosaurs except those strongly adapted for fast-swimming life in the open ocean. Due to this pattern, it has been assumed that ichthyosaurs were constantly and rapidly evolving to be ever-faster open-water swimmers; seemingly, there was no ‘stasis’ in their long evolutionary history.

However, an entirely new ichthyosaur from the Kurdistan region of Iraq substantially alters this view of the group. The specimen concerned was found during the 1950s by British petroleum geologists. “The fossil — a well-preserved partial skeleton that consists of much of the front half of the animal — wasn’t exactly being treated with the respect it deserves. Preserved within a large, flat slab of rock, it was being used as a stepping stone on a mule track,” says co-author Darren Naish of the University of Southampton. “Luckily, the geologists realized its potential importance and took it back to the UK, where it remains today,” adds Dr Naish, who is based at the National Oceanography Centre, Southampton.

Study of the specimen began during the 1970s with ichthyosaur expert Robert Appleby, then of University College, Cardiff. “Robert Appleby recognised that the specimen was significant, but unfortunately died before resolving the precise age of the fossil, which he realised was critical,” says Jeff Liston of National Museums Scotland and manager of the research project. “So continuation of the study fell to a new generation of researchers.”

In the new study (which properly includes Appleby as an author), researchers name it Malawania anachronus, which means ‘out of time swimmer’. Despite being Cretaceous in age, Malawania represents the last-known member of a kind of ichthyosaur long believed to have gone extinct during the Early Jurassic, more than 66 million years earlier. Remarkably, this kind of archaic ichthyosaur appears characterised by an evolutionary stasis: they seem not to have changed much between the Early Jurassic and the Cretaceous, a very rare feat in the evolution of marine reptiles.

“Malawania’s discovery is similar to that of the coelacanth in the 1930s: it represents an animal that seems ‘out of time’ for its age. This ‘living fossil’ of its time demonstrates the existence of a lineage that we had never even imagined. Maybe the existence of such Jurassic-style ichthyosaurs in the Cretaceous has been missed because they always lived in the Middle-East, a region that has previously yielded only a single, very fragmentary ichthyosaur fossil,” adds Dr Fischer.

Thanks to both their study of microscopic spores and pollen preserved on the same slab as Malawania, and to their several analyses of the ichthyosaur family tree, Fischer and his colleagues retraced the evolutionary history of Cretaceous ichthyosaurs. In fact, the team was able to show that numerous ichthyosaur groups that appeared during the Triassic and Jurassic ichthyosaur survived into the Cretaceous. It means that the supposed end of Jurassic extinction event did not ever occur for ichthyosaurs, a fact that makes their fossil record quite different from that of other marine reptile groups.

When viewed together with the discovery of another ichthyosaur by the same team in 2012 and named Acamptonectes densus, the discovery of Malawania constitutes a ‘revolution’ in how we imagine ichthyosaur evolution and extinction. It now seems that ichthyosaurs were still important and diverse during the early part of the Cretaceous. The final extinction of the ichthyosaurs — an event that occurred about 95 million years ago (long before the major meteorite-driven extinction event that ended the Cretaceous) — is now even more confusing than previously assumed.

Mum and Dad Dinosaurs Shared the Work

May 15, 2013 — A study into the brooding behaviour of birds has revealed their dinosaur ancestors shared the load when it came to incubation of eggs.


Research into the incubation behaviour of birds suggests the type of parental care carried out by their long extinct ancestors.

The study aimed to test the hypothesis that data from extant birds could be used to predict the incubation behaviour of Theropods, the group of carnivorous dinosaurs from which birds descended.

The paper, out today in Biology Letters, was co-authored by Dr Charles Deeming and Dr Marcello Ruta from the University of Lincoln’s School of Life Sciences and Dr Geoff Birchard from George Mason University, Virginia.

By taking into account factors known to affect egg and clutch size in living bird species, the authors — who started their investigation last summer at the University of Lincoln’s Riseholme campus — found that shared incubation was the ancestral incubation behaviour. Previously it had been claimed that only male Theropod dinosaurs incubated the eggs.

Dr Deeming said: “In 2009 a study in the journal Science suggested that it was males of the small carnivorous dinosaurs Troodon and Oviraptor that incubated their eggs. Irrespective of whether you accept the idea of Theropod dinosaurs sitting on eggs like birds or not, the analysis raised some concerns that we wanted to address. We decided to repeat the study with a larger data set and a better understanding of bird biology because other palaeontologists were starting to use the original results in Science in order to predict the incubation behaviour of other dinosaur species. Our analysis of the relationship between female body mass and clutch mass was interesting in its own right but also showed that it was not possible to conclude anything about incubation in extinct distant relatives of the birds.”

Palaeobiologist Dr Ruta was involved in mapping the parental behaviour in modern birds on to an evolutionary tree.

Dr Ruta said: “As always in any study involving fossils, knowledge of extant organisms helps us make inferences about fossils. Fossils have a unique role in shaping our knowledge of the Tree of Life and the dynamics of evolutionary processes. However, as is the case with our study, data from living organisms may augment and refine the potential of fossil studies and may shift existing notions of the biology and behaviour of long extinct creatures.”

Dr Birchard added: “The previous study was carried out to infer the type of parental care in dinosaurs that are closely related to birds. That study proposed that paternal care was present in these dinosaurs and this form of care was the ancestral condition for birds. Our new analysis based on three times as many species as in the previous study indicates that parental care cannot be inferred from simple analyses of the relationship of body size to shape, anatomy, physiologyand behaviour. Such analyses ought to take into account factors such as shared evolutionary history and maturity at hatching. However, our data does suggest that the dinosaurs used in the previous study were likely to be quite mature at birth.”

The project has helped in understanding the factors affecting the evolution of incubation in birds. More importantly it is hoped that the new analysis will assist palaeontologists in their interpretation of future finds of dinosaur reproduction in the fossil record.