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.
Unique images bring fossil insects back to life
A groundbreaking new book that brings together two of the major disciplines behind Jurassic Park is aiming to raise the profile of insect fossils through stunning photographs and unique illustrations.
Fossil Insects, by Dr David Penney and James E Jepson, details the incredible preservation and diversity of fossilised insects from around the world, setting the scene for what these remarkable fossils can tell us about the ancient and modern worlds, and even the future of our planet. Like the mosquito in Jurassic Park, many of the hundreds of thousands of specimens of ancient insect have been preserved in amber.
Using pioneering scientific methods and state of the art technology Dr David Penney from The University of Manchester has drawn on his knowledge of both entomology and palaeontology to discover some astonishing things about these fossilized creatures during the course of his research.
He says: “Insects are the most diverse group of creatures on the planet today. Many of them were around even before the time of the dinosaurs. Bringing together entomology and palaeontology through the study of insect fossils has great potential for revolutionising what we know about both subjects.”
The ancient insects have been brought to life in the book through illustrations that for the first time depict long vanished arthropods living among the flora and fauna during the age of the dinosaurs. In a unique collaboration the artist Richard Bizley has created seven reconstructions of each of the major periods from the Devonian through to the Tertiary.
To make the animals in his paintings look realistic, Richard created models using scientific drawings and pictures of fossils. He then photographed them to see how the light behaves.
Richard says: “When reconstructing fossil insect species, special attention needs to be paid to important diagnostic features, such as the wing venation patterns and the relative lengths of appendage segments. The fact that many fossil insect species are known only from isolated wings posed additional problems. This is where the collaboration with experts became very useful and I worked closely with Dr Penney to produce an accurate reconstruction based on the comparative study of both fossil and living insects.”
He continues: “Plants can be difficult, especially as we are unsure how some of them looked. It is rare to get a fossil of a whole plant, so I had to paint according to the best estimation of how they looked, using the evidence available. Fortunately, scientists have learnt enough to provide some good ideas and many living plants are closely related to those that have become extinct.”
Whilst Jurassic Park remains a fantasy for now Dr Penney says the book and the film did result in an increase in research on fossil insects. He’s now hoping that his book, Fossil Insects, will open up the research to even more people.
He says: “This is the first book to merge these two disciplines in an accessible way, using plain and simple language. It is a book for anyone with a passion for palaeontology and/or entomology.”
Striking lack of diversity in prehistoric birds
Birds come in astounding variety — from hummingbirds to emus — and behave in myriad ways: they soar the skies, swim the waters, and forage the forests. But this wasn’t always the case, according to research by scientists at the University of Chicago and the Field Museum.
The researchers found a striking lack of diversity in the earliest known fossil bird fauna (a set of species that lived at about the same time and in the same habitat). “There were no swans, no swallows, no herons, nothing like that. They were pretty much all between a sparrow and a crow,” said Jonathan Mitchell, PhD student in the Committee on Evolutionary Biology, and lead author of the new study, published May 28, 2014, in Proceedings of the Royal Society B.
The scientists examined a group of bird fossils dating back to the Cretaceous period, around 125 million years ago, relatively soon after the emergence of birds. The fossils were collected from an area in China where there was once violent volcanic activity, leading to a plethora of well-preserved fossils as intermittent eruptions periodically killed many birds. The researchers examined the diversity of species in this sample. However, because fossils indicate only the physical characteristics of the birds, understanding the diversity in how the birds behaved required significant scientific legwork.
To tease out the ecological roles played by the prehistoric birds, the researchers used modern-day birds to build a statistical technique that could relate the physical characteristics of a bird to its diet, behavior and habitat. Long legs might be associated with birds that wade through water, for instance, and the shape of the beak might hint at what the bird ate. For this purpose, the scientists painstakingly measured 1,400 modern birds — mostly from the Field Museum’s collections — and extracted the correlations between these measurements and the birds’ behavior.
Toothy birds
However, the scientists still had to show that this technique, which was useful for modern birds, could be applied effectively to the distinct sample of ancient birds. “These birds are very different from modern birds — some of them have teeth, some of them have long bony tails,” said Mitchell. Therefore, it wasn’t clear if the method would translate.
In order to test the method, they looked at the contents of the birds’ stomachs — the last meals they ate before their demise — which in some cases had survived the process of fossilization. They found agreement between the method’s predictions and the birds’s diet, indicating that it worked for ancient birds as well.
Once they had confirmed that the method was effective for the fossil birds with food preserved in their bellies, the scientists applied their method to the full complement of the region’s bird fossils. They found that these early birds were less diverse than modern birds. In particular, larger birds and water birds were lacking. “They were all pretty much the same. They were ground-dwelling or forest-dwelling little birds, mostly eating insects and seeds,” said Mitchell.
Fossilization bias?
A possible confounding factor was the bias potentially introduced by the fossilization process. Some types of birds might become fossilized more often than others, artificially reducing the diversity. To examine this possibility, the scientists compared very recent bird fossils to the populations of modern-day birds. They found that the fossilized sample was less diverse, although not enough to explain the effect they had seen in the very old fossils.
Additionally, the fossils were biased towards larger birds, and birds that lived in water. That is the opposite effect from the one seen in the oldest fossils, which were mostly composed of small land-dwellers, so the scientists concluded that this bias could not be the cause of the homogeneous birds.
The scientists’ research is beginning to untangle some possible reasons for this lack of diversity. One feasible explanation is that early birds were less diverse due to competition with similar groups — such as the prehistoric flying reptiles known as pterosaurs. But the scientists used an evolutionary model to show that the paucity of ecological niches could be explained simply by the fact that birds were new to the scene, and thus hadn’t had time to diversify. “It looks like they just hadn’t evolved the crazy diversity of ecologies that we see in modern birds,” said Mitchell.
The research was carried out through UChicago’s Committee on Evolutionary Biology, an interdisciplinary graduate program, which allows for collaborative work between students at the university and outside research institutions such as the Field Museum. Peter Makovicky, associate curator of paleontology and chair of the Field Museum’s department of geology, was co-author. The program, Makovicky said, is a great place for students to “really tackle these big-picture questions.”
The results have implications for when and how birds originated — a topic under some debate — as well as for the study of evolution in general. “In a broader sense, I think that our research speaks to an understanding of how groups of organisms, which are perhaps dominant today in modern ecosystems, get to that point,” Makovicky, said. Birds, for example, evolved from humble beginnings into the diverse group we know today. The early bird, therefore, may indeed have gotten the worm — or the insect or seed — but not much else.
Age-old relationship between birds and flowers: World’s oldest fossil of a nectarivorous bird
Scientists of the Senckenberg Research Institute in Frankfurt have described the oldest known fossil of a pollinating bird. The well-preserved stomach contents contained pollen from various flowering plants. This indicates that the relationship between birds and flowers dates back at least 47 million years. The fossil comes from the well-known fossil site “Messel Pit.” The study was published today in the scientific journal Biology Letters.
They fly from flower to flower, and with their long, slender bills they transfer the pollen required for the plants’ reproduction. Particularly in the tropics and subtropics, birds, besides insects, serve as the most important pollinators.
“While this process is well known and understood in the present, geological history has offered very little evidence of pollination through birds,” says Dr. Gerald Mayr, head of the Ornithological Section at the Senckenberg Research Institute in Frankfurt. He adds, “there have been occasional hints, such as characteristic bill shapes, that nectarivorous birds occurred in the past, but, so far, there existed no conclusive evidence.”
Now, however, the ornithologist from Frankfurt and his colleague, paleobotanist Dr. Volker Wilde, have found this evidence. In the well-preserved stomach contents of a fossil bird unearthed in the Messel Pit, the scientists discovered fossilized pollen grains.
“This is another discovery that underlines the unique significance of the Messel fossil site,” exclaims a delighted Dr. Wilde. “Not only does the presence of pollen offer direct evidence of the bird’s feeding habits, but it shows that birds already visited flowers as long as 47 million years ago!”
Fossil evidence for the existence of pollinating insects dates back to the Cretaceous period. Until now, however, there had been no information at what time pollination through vertebrates, and birds in particular, came into existence. To date, the oldest indication of an avian pollinator came from the early Oligocene, about 30 million years ago. “But this hummingbird fossil only offers indirect evidence of the existence of nectarivorous birds,” explains Mayr. “Thanks to the excellent state of preservation of the Messel bird, we were able to identify two different types of pollen, which is the first conclusive proof of nectarivory.”
Large numbers of differently sized pollen grains were found in the stomach contents of the completely preserved avian fossil. “Along with the bird’s skeletal anatomy, this indicates that we indeed have the fossil of a nectarivorous bird” explains Wilde.
And the spectacular discovery also suggests another conclusion: If a pollinating bird lived as much as 47 million years ago, it must be assumed that some representatives of the flora at that time had already adapted to this mode of pollination.
“To date, there are no fossil plants from this geological era that offer proof of the existence of ornithophily — i.e., the pollination of flowers through birds,” adds paleobotanist Wilde.
“However, the characteristic traits of bird-pollinated plants, such as red flowers or a lack of scent, do not fossilize,” elaborates Mayr. This lends an even greater importance to discoveries such as the Messel bird to understand the interactions between birds and flowers through geological time.
Computer rendering: Graduate student brings extinct plants ‘back to life’
Jeff Benca is an admitted über-geek when it comes to prehistoric plants, so it was no surprise that, when he submitted a paper describing a new species of long-extinct lycopod for publication, he ditched the standard line drawing and insisted on a detailed and beautifully rendered color reconstruction of the plant. This piece earned the cover of March’s centennial issue of the American Journal of Botany
Benca described this 400-million-year-old fossil lycopod, Leclercqia scolopendra, and created a life-like computer rendering. The stem of the lycopod is about 2.5 millimeters across.
“Typically, when you see pictures of early land plants, they’re not that sexy: there is a green forking stick and that’s about it. We don’t have many thorough reconstructions,” said Benca, a graduate student in the Department of Integrative Biology and Museum of Paleontology at UC Berkeley. “I wanted to give an impression of what they may have really looked like. There are great color reconstructions of dinosaurs, so why not a plant?”
Benca’s realistic, full-color image could be a life portrait, except for the fact that it was drawn from a plant that lay flattened and compressed into rock for more than 375 million years.
Called Leclercqia scolopendra, or centipede clubmoss, the plant lived during the “age of fishes,” the Devonian Period. At that time, lycopods — the group Leclercqia belonged to — were one of few plant lineages with leaves. Leclercqia shoots were about a quarter-inch in diameter and probably formed prickly, scrambling, ground-covering mats. The function of Leclercqia’s hook-like leaf tips is unclear, Benca said, but they may have been used to clamber over larger plants. Today, lycopods are represented by a group of inconspicuous plants called club mosses, quillworts and spikemosses.
Both living and extinct lycopods have fascinated Benca since high school. When he came to UC Berkeley last year from the University of Washington, he brought a truckload of some 70 different species, now part of collections at the UC Botanical Garden.
Now working in the paleobotany lab of Cindy Looy, Berkeley assistant professor of integrative biology, Benca continues to establish a growing list of living lycopod species, several of which will eventually be incorporated into the UC and Jepson Herbaria collections.
Visualizing plant evolution
Benca and colleagues wrote their paper primarily to demonstrate a new technique that is helping paleobotanists interpret early land plant fossils with greater confidence. Since living clubmosses share many traits with early lycopods, the research team was able to test their methods using living relatives Benca was growing in greenhouses.
Early land plant fossils are not easy to come by, but they can be abundant in places where rocks from the Devonian Period form outcrops. But a large portion of these are just stem fragments with few diagnostic features to distinguish them, Benca said.
“The way we analyzed Leclercqia material makes it possible to gain more information from these fragments, increasing our sample size of discernible fossils,” he said.
“Getting a better grip on just how diverse and variable Devonian plants were will be important to understanding the origins of key traits we see in so many plants today.” Looy said. Benca’s co-authors are Maureen H. Carlisle, Silas Bergen and Caroline A. E. Strömberg from the University of Washington and Burke Museum of Natural History and Culture, Seattle.
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: http://www.youtube.com/watch?v=jK_DKSNbgR4&feature=youtu.be
“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.”
Rare fossilized embryos more than 500 million years old found
The Cambrian Period is a time when most phyla of marine invertebrates first appeared in the fossil record. Also dubbed the “Cambrian explosion,” fossilized records from this time provide glimpses into evolutionary biology when the world’s ecosystems rapidly changed and diversified. Most fossils show the organisms’ skeletal structure, which may or may not give researchers accurate pictures of these prehistoric organisms. Now, researchers at the University of Missouri have found rare, fossilized embryos they believe were undiscovered previously. Their methods of study may help with future interpretation of evolutionary history.
“Before the Ediacaran and Cambrian Periods, organisms were unicellular and simple,” said James Schiffbauer, assistant professor of geological sciences in the MU College of Arts and Science. “The Cambrian Period, which occurred between 540 million and 485 million years ago, ushered in the advent of shells. Over time, shells and exoskeletons can be fossilized, giving scientists clues into how organisms existed millions of years ago. This adaptation provided protection and structural integrity for organisms. My work focuses on those harder-to-find, soft-tissue organisms that weren’t preserved quite as easily and aren’t quite as plentiful.”
Schiffbauer and his team, including Jesse Broce, a Huggins Scholar doctoral student in the Department of Geological Sciences at MU, now are studying fossilized embryos in rocks that provide rare opportunities to study the origins and developmental biology of early animals during the Cambrian explosion.
Broce collected fossils from the lower Cambrian Shuijingtuo Formation in the Hubei Province of South China and analyzed samples to determine the chemical makeup of the rocks. Soft tissue fossils have different chemical patterns than harder, skeletal remains, helping researchers identify the processes that contributed to their preservation. It is important to understand how the fossils were preserved, because their chemical makeups can also offer clues about the nature of the organisms’ original tissues, Schiffbauer said.
“Something obviously went wrong in these fossils,” Schiffbauer said. “Our Earth has a pretty good way of cleaning up after things die. Here, the cells’ self-destructive mechanisms didn’t happen, and these soft tissues could be preserved. While studying the fossils we collected, we found over 140 spherically shaped fossils, some of which include features that are reminiscent of division stage embryos, essentially frozen in time.”
The fossilized embryos the researchers found were significantly smaller than other fossil embryos from the same time period, suggesting they represent a yet undescribed organism. Additional research will focus on identifying the parents of these embryos, and their evolutionary position.
Schiffbauer and his colleagues published this and related research in a volume of the Journal of Paleontology which he co-edited.
Nearly complete ‘chicken from hell,’ from mysterious dinosaur group
A Team of researchers has announced the discovery of a bizarre, bird-like dinosaur, named Anzu wyliei, that provides paleontologists with their first good look at a dinosaur group that has been shrouded in mystery for almost a century. Anzu was described from three specimens that collectively preserve almost the entire skeleton, giving scientists a remarkable opportunity to study the anatomy and evolutionary relationships of Caenagnathidae (pronounced SEE-nuh-NAY-thih-DAY) — the long-mysterious group of theropod dinosaurs to which Anzu belongs.
The three described fossil skeletons of Anzu were unearthed in North and South Dakota, from roughly 66 million-year-old rocks of the Hell Creek Formation, a rock unit celebrated for its abundant fossils of famous dinosaurs such as Tyrannosaurus rex and Triceratops. The scientific paper describing the discovery appears today in the freely-accessible journal PLOS ONE.
The team of scientists who studied Anzu was led by Dr. Matthew Lamanna of Carnegie Museum of Natural History in Pittsburgh. Dr. Lamanna’s collaborators include Dr. Hans-Dieter Sues and Dr. Tyler Lyson of the Smithsonian Institution’s National Museum of Natural History in Washington, DC, and Dr. Emma Schachner of the University of Utah in Salt Lake City. According to Dr. Lamanna, “Anzu is far and away the most complete caenagnathid that has ever been discovered. After nearly a century of searching, we paleontologists finally have the fossils to show what these creatures looked like from virtually head to toe. And in almost every way, they’re even weirder than we imagined.”
Hell’s Chicken
At roughly 11 feet long and five feet tall at the hip, Anzu would have resembled a gigantic flightless bird, more than a ‘typical’ theropod dinosaur such as T. rex. Its jaws were tipped with a toothless beak, and its head sported a tall, rounded crest similar to that of a cassowary (a large ground bird native to Australia and New Guinea). The neck and hind legs were long and slender, also comparable to a cassowary or ostrich. Although the Anzu specimens preserve only bones, close relatives of this dinosaur have been found with fossilized feathers, strongly suggesting that the new creature was feathered too. The resemblance to birds ends there, however: the forelimbs ofAnzu were tipped with large, sharp claws, and the tail was long and robust. Says Dr. Lamanna, “We jokingly call this thing the ‘Chicken from Hell,’ and I think that’s pretty appropriate. So we named it after Anzu, a bird-like demon in ancient mythology.”
The species is named for a Carnegie Museums of Pittsburgh Trustee’s grandson, Wylie.
Not only do the fossils of Anzu wyliei paint a picture of this particular species, they shed light on an entire group of dinosaurs, the first evidence of which was discovered almost 100 years ago. In 1924, paleontologist Charles Whitney Gilmore described the species Chirostenotes pergracilis from a pair of fossil hands found a decade earlier in ~74 million-year-old rocks in Alberta, Canada. Later, in 1940, Caenagnathus collinsiwas named, based on a peculiar lower jaw from the same beds. More recently, after studies of these and other fragmentary fossils, Hans Sues and other paleontologists determined that Chirostenotes and Caenagnathus belonged to the same dinosaur group, Caenagnathidae, and that these animals were close cousins of Asian oviraptorid theropods such as Oviraptor.
Asian relations
Oviraptor (‘egg thief’) is widely known because the first fossil skeleton of this animal, described in 1924, was found atop a nest of dinosaur eggs, suggesting that the creature had died in the act of raiding the nest. This thinking prevailed until the 1990s, when the same type of egg was found with a baby oviraptorid inside, demonstrating that, rather than a nest plunderer, Oviraptor was a caring parent that perished while protecting its eggs. More than a dozen oviraptorid species have been discovered, all in Mongolia and China, and many are known from beautifully-preserved, complete or nearly complete skeletons. Additionally, beginning in the 1990s, several small, primitive relatives of oviraptorids were unearthed in much older, ~125 million-year-old rocks in northeastern China. Many of these are also represented by complete skulls or skeletons, some of which preserve fossilized feathers. Researchers have established that caenagnathids, oviraptorids, and these more archaic Chinese species are closely related to one another, and have united them as the theropod group Oviraptorosauria. The occurrence of oviraptorosaurs in both Asia and North America was not a surprise to paleontologists, because these continents were frequently connected during the Mesozoic Era (the ‘Age of Dinosaurs’), allowing dinosaurs and other land animals to roam between them. However, because their fossils were so incomplete, caenagnathids remained the most poorly known members of Oviraptorosauria, and indeed, one of the least understood of all major dinosaur groups. “For many years, caenagnathids were known only from a few bits of the skeleton, and their appearance remained a big mystery,” says Dr. Sues.
More fossils, more knowledge
The nearly completely represented skeleton of Anzu opens a window into the anatomy of this and other caenagnathid species. Armed with this wealth of new information, Dr. Lamanna and his team were able to reconstruct the evolution of these extraordinary animals in more detail than ever before. Analysis of the relationships of Anzureaffirmed that caenagnathids form a natural grouping within Oviraptorosauria: Anzu,Caenagnathus, Chirostenotes, and other North American oviraptorosaurs are more closely related to each other than they are to most of their Asian cousins — a finding that had been disputed in recent years. Furthermore, the team’s analysis confirmed the recent hypothesis that the enormous (and aptly-named) Gigantoraptor — at a weight of at least 1.5 tons, the largest oviraptorosaur known to science — is an unusual member of Caenagnathidae as well, instead of an oviraptorid as had initially been proposed. “We’re finding that caenagnathids were an amazingly diverse bunch of dinosaurs,” says Dr. Lamanna. “Whereas some were turkey-sized, others — like Anzuand Gigantoraptor — were the kind of thing you definitely wouldn’t want to meet in a dark alley. Apparently these oviraptorosaurs occupied a much wider range of body sizes and ecologies than we previously thought.”
The anatomy and ancient environment of Anzu provide insight into the diet and habitat preferences of caenagnathids as well. Although the preferred food of these oviraptorosaurs remains something of a puzzle, Dr. Lamanna and collaborators think that caenagnathids were probably omnivores — like humans, animals that could eat either meat or plants. Moreover, studies of the rocks in which several of the most complete caenagnathid skeletons have been found show that these strata were laid down in humid floodplain environments, suggesting that these dinosaurs favored such habitats. In this way, caenagnathids appear to have differed greatly from their oviraptorid cousins, all of which have been found in rocks that were deposited under arid to semi-arid conditions . “Over the years, we’ve noticed that Anzu and some other Hell Creek Formation dinosaurs, such as Triceratops, are often found in mudstone rock that was deposited on ancient floodplains. Other dinosaurs, like duckbills, are found in sandstone deposited in or next to rivers,” says Dr. Lyson, who found his first Hell Creek fossil on his family’s ranch in North Dakota when he was only six years old.
Anzu led a life that was fraught with danger. In addition to sharing its Cretaceous world with the most notorious carnivore of all time — T. rex — this oviraptorosaur seems to have gotten hurt a lot as well. Two of the three specimens show clear evidence of injuries: one has a broken and healed rib, while the other has an arthritic toe bone that may have been caused by an avulsion fracture (where a tendon ripped a piece off the bone to which it was attached). Says Dr. Schachner, “These animals were clearly able to survive quite a bit of trauma, as two of the specimens show signs of semi-healed damage. Whether these injuries were the result of combat between two individuals or an attack by a larger predator remains a mystery.”
As much insight as the Anzu skeletons provide, paleontologists still have much to learn about North American oviraptorosaurs. Ongoing studies of these and other important fossils promise to remove more of the mystery surrounding these remarkable bird-like creatures. “For nearly a hundred years, we paleontologists knew almost nothing about these dinosaurs,” concludes Dr. Lamanna. “Now, thanks to Anzu, we’re finally starting to figure them out.”
A fully-articulated cast of Anzu wyliei is on public view in Carnegie Museum of Natural History’s Dinosaurs in Their Time exhibition.
Dinosaur skull may reveal T. rex’s smaller cousin from the north
A 70 million year old fossil found in the Late Cretaceous sediments of Alaska reveals a new small tyrannosaur, according to a paper published in the open-access journal PLOS ONE on March 12, 2014 by co-authors Anthony Fiorillo and Ronald S. Tykoski from Perot Museum of Nature and Science, Texas, and colleagues.
Tyrannosaurs, the lineage of carnivorous theropod (“beast feet”) dinosaurs that include T. rex, have captivated our attention, but the majority of our knowledge about this group comes from fossils from low- to mid-latitudes of North America and Asia. In this study, scientists analyzed the partial skull roof, maxilla, and jaw, recovered from Prince Creek Formation in Northern Alaska, of a dinosaur originally believed to belong to a different species, and then compared the fossils to known tyrannosaurine species.
According to the results of the authors’ analysis, the cranial bones represent Nanuqsaurus hoglundi, a new tyrannosaurine species closely related to two other tyrannosaurides, Tarbosaurus and Tyrannosaurus. This new dinosaur is estimated to be relatively small, with an adult skull length estimated at 25 inches, compared to 60 inches for T. rex. The new species likely inhabited a seasonally extreme, high-latitude continental environment on the northernmost edge of Cretaceous North America.
The authors suggest that the smaller body size of N. hoglundi compared to most tyrannosaurids from lower latitudes may reflect an adaptation to variability in resources in the arctic seasons. Further diversification may stem from the dinosaurs’ partial isolation in the north by land barriers, such as the east-west running Brooks Range. Although the preserved elements of N. hoglundi are fragments, the authors point to morphological data to provide support for its place among derived tyrannosaurines. This discovery may provide new insights into the adaptability and evolution of tyrannosaurs in a different environment, the Arctic.
“The ‘pygmy tyrannosaur’ alone is really cool because it tells us something about what the environment was like in the ancient Arctic,” said Fiorillo. “But what makes this discovery even more exciting is that Nanuqsaurus hoglundi also tells us about the biological richness of the ancient polar world during a time when the Earth was very warm compared to today.”
First discovery of dinosaur fossils in Malaysia
A team of palaeontology researchers from the Department of Geology, Faculty of Science, University of Malaya and Japanese universities (Waseda University and Kumamoto University) has found dinosaur fossil teeth in the rural interiors of Pahang — the first known discovery of dinosaur remains in Malaysia.
“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.