Decades-old amber collection offers new views of a lost world: Tiny grasshopper encased in amber
Scientists are searching through a massive collection of 20-million-year-old amber found in the Dominican Republic more than 50 years ago, and the effort is yielding fresh insights into ancient tropical insects and the world they inhabited.
When the collection is fully curated, a task that will take many years, it will be the largest unbiased Dominican amber collection in the world, the researchers report.
Perhaps the most striking discovery thus far is that of a pygmy locust, a tiny grasshopper the size of a rose thorn that lived 18- to 20-million years ago and fed on moss, algae and fungi. The specimen is remarkable because it represents an intermediate stage of evolution in the life of its subfamily of locusts (known as the Cladonotinae). The most ancient representatives of this group had wings, while modern counterparts do not. The newly discovered locust has what appear to be vestigial wings — remnant structures that had already lost their primary function.
The discovery is reported in the journal ZooKeys.
“Grasshoppers are very rare in amber and this specimen is extraordinarily well-preserved,” said Sam Heads, a paleontologist at the Illinois Natural History Survey, a division of the Prairie Research Institute at the University of Illinois.
Heads, laboratory technician Jared Thomas and study co-author Yinan Wang found the new specimen a few months after the start of their project to screen more than 160 pounds of Dominican amber collected in the late 1950s by former INHS entomologist Milton Sanderson. Sanderson described several specimens from the collection in a paper in Science in 1960, a report that inspired a generation of scientists to seek out and study Dominican amber, Heads said.
The bulk of the Sanderson amber collection remained in storage, however, until Heads uncovered it in 2010.
Heads has named the new pygmy locust Electrotettix attenboroughi, the genus name a combination of electrum (Latin from Greek, meaning “amber”) and tettix (Greek, meaning “grasshopper”). The species is named for Sir David Attenborough, a British naturalist and filmmaker (not to be confused with Richard Attenborough, David’s actor brother who appeared in the movie “Jurassic Park”).
“Sir David has a personal interest in amber, and also he was one of my childhood heroes and still is one of my heroes and so I decided to name the species in his honor — with his permission of course,” Heads said. (Attenborough narrates and appears in a new video about the Sanderson collection and the specimen that bears his name.)
The process of screening the amber is slow and painstaking. Much of the amber is clouded with oxidation, and the researchers must carefully cut and polish “windows” in it to get a good look at what’s inside. In addition to the pygmy locust, Heads and his colleagues have found mating flies, stingless bees, gall midges, Azteca ants, wasps, bark beetles, mites, spiders, plant parts and even a mammal hair.
The pygmy locust was found in a fragment that also contained wasps, ants, midges, plant remnants and fungi. Such associations are rich in information, Heads said, offering clues about the creatures’ physiological needs and the nature of their habitat.
“Fossil insects can provide lots of insight into the evolution of specific traits and behaviors, and they also tell us about the history of the time period,” Heads said. “They’re a tremendous resource for understanding the ancient world, ancient ecosystems and the ancient climate — better even, perhaps, than dinosaur bones.”
The National Science Foundation supports this work. Heads and his colleagues are digitizing the best specimens, and will upload the images onto a publicly available website.
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.”
Dinosaurs fell victim to perfect storm of events, study shows
Dinosaurs might have survived the asteroid strike that wiped them out if it had taken place slightly earlier or later in history, scientists say.
A fresh study using up-to-date fossil records and improved analytical tools has helped palaeontologists to build a new narrative of the prehistoric creatures’ demise, some 66 million years ago.
They found that in the few million years before a 10km-wide asteroid struck what is now Mexico, Earth was experiencing environmental upheaval. This included extensive volcanic activity, changing sea levels and varying temperatures.
At this time, the dinosaurs’ food chain was weakened by a lack of diversity among the large plant-eating dinosaurs on which others preyed. This was probably because of changes in the climate and environment.
This created a perfect storm in which dinosaurs were vulnerable and unlikely to survive the aftermath of the asteroid strike.
The impact would have caused tsunamis, earthquakes, wildfires, sudden temperature swings and other environmental changes. As food chains collapsed, this would have wiped out the dinosaur kingdom one species after another. The only dinosaurs to survive were those who could fly, which evolved to become the birds of today.
Researchers suggest that if the asteroid had struck a few million years earlier, when the range of dinosaur species was more diverse and food chains were more robust, or later, when new species had time to evolve, then they very likely would have survived.
An international team of palaeontologists led by the University of Edinburgh studied an updated catalogue of dinosaur fossils, mostly from North America, to create a picture of how dinosaurs changed over the few million years before the asteroid hit. They hope that ongoing studies in Spain and China will aid even better understanding of what occurred.
Their study, published in Biological Reviews, was supported by the US National Science Foundation and the European Commission. It was led by the Universities of Edinburgh and Birmingham in collaboration with the University of Oxford, Imperial College London, Baylor University, and University College London. The world’s top dinosaur museums — The Natural History Museum, the Smithsonian Institution, the Royal Ontario Museum, the American Museum of Natural History and the New Mexico Museum of Natural History and Science — also took part.
Dr Steve Brusatte, of the University of Edinburgh’s School of GeoSciences, said: “The dinosaurs were victims of colossal bad luck. Not only did a giant asteroid strike, but it happened at the worst possible time, when their ecosystems were vulnerable. Our new findings help clarify one of the enduring mysteries of science.”
Dr Richard Butler of the School of Geography, Earth and Environmental Sciences at the University of Birmingham, said: “There has long been intense scientific debate about the cause of the dinosaur extinction. Although our research suggests that dinosaur communities were particularly vulnerable at the time the asteroid hit, there is nothing to suggest that dinosaurs were doomed to extinction. Without that asteroid, the dinosaurs would probably still be here, and we very probably would not.”
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.
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.”
Fossils of earliest stick insect to mimic plants discovered: Ancient stick insect species mimicked plant leaves
An ancient stick insect species may have mimicked plant leaves for defense, according to a paper published in the open-access journalPLOS ONE on March 19, 2014 by Maomin Wang, from Capital Normal University, China and colleagues.
Many insects have developed defense mechanisms, including the ability to mimic the surrounding environment. Stick and leaf insects mimic plants from their environment, but scientists know little about the original of this interaction due to little or no previous stick insect fossil records showing this adaptation. The scientists discovered three specimens, one female and two males, belonging to a new fossil stick insect referred to as Cretophasmomima melanogramma, in Inner Mongolia at the Jehol locality, a site from the Cretaceous period (approximately 126 million years ago). The species possessed adaptive features that make it resembling a plant recovered from the same locality.
The insects’ wings have parallel dark lines and when in the resting position, likely produced a tongue-like shape concealing the abdomen. Fossils from a relative of the ginkgo plant have been documented in the area with similar tongue-shaped leaves along with multiple longitudinal lines. The authors suggest the insect used this plant as a model for concealment.
The new fossils indicate that leaf mimicry was a defensive strategy performed by some insects as early as in the Early Cretaceous, but that additional refinements characteristic of recent forms, such as a curved part of the fore legs for hiding the head, were still lacking.
The new fossil suggests that leaf mimicry predated the appearance of twig and bark mimicry in these types of insects. The diversification of small-sized, insect-eating birds and mammals may have triggered the acquisition of such primary defenses.
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.”
Mass strandings of marine mammals blamed on toxic algae: Clues unearthed in ancient whale graveyard
Mass strandings of whales have puzzled people since Aristotle. Modern-day strandings can be investigated and their causes, often human-related, identified. Events that happened millions of years ago, however, are far harder to analyze — frequently leaving their cause a mystery. A team of Smithsonian and Chilean scientists examined a large fossil site of ancient marine mammal skeletons in the Atacama Desert of Northern Chile — the first definitive example of repeated mass strandings of marine mammals in the fossil record. The site reflected four distinct strandings over time, indicating a repeated and similar cause: toxic algae. The team’s findings will be published Feb. 26 in the Proceedings of the Royal Society B.
The site was first discovered during an expansion project of the Pan-American Highway in 2010. The following year, paleontologists from the Smithsonian and Chile examined the fossils, dating 6-9 million years ago, and recorded what remained before the site was paved over.
The team documented the remains of 10 kinds of marine vertebrates from the site, named Cerro Ballena — Spanish for “whale hill.” In addition to the skeletons of the more than 40 large baleen whales that dominated the site, the team documented the remains of a species of sperm whale and a walrus-like whale, both of which are now extinct. They also found skeletons of billfishes, seals and aquatic sloths.
What intrigued the team most, however, was how the skeletons were arranged. The skeletons were preserved in four separate levels, pointing to a repeated and similar underlying cause. The skeletons’ orientation and condition indicated that the animals died at sea, prior to burial on a tidal flat.
Effects of Toxic Algae
Today, toxins from harmful algal blooms, such as red tides, are one of the prevalent causes for repeated mass strandings that include a wide variety of large marine animals.
“There are a few compelling modern examples that provide excellent analogs for the patterns we observed at Cerro Ballena — in particular, one case from the late 1980s when more than a dozen humpback whales washed ashore near Cape Cod, with no signs of trauma, but sickened by mackerel loaded with toxins from red tides,” said Nicholas Pyenson, paleontologist at the Smithsonian’s National Museum of Natural History and lead author of the research. “Harmful algal blooms in the modern world can strike a variety of marine mammals and large predatory fish. The key for us was its repetitive nature at Cerro Ballena: no other plausible explanation in the modern world would be recurring, except for toxic algae, which can recur if the conditions are right.”
Harmful algal blooms are common along the coasts of continents; they are enhanced by vital nutrients, such as iron, released during erosion and carried by rivers flowing into the ocean. Because the Andes of South America are iron-rich, the runoff that has occurred along the west coast of South America for more than 20 million years has long provided the ideal conditions for harmful algal blooms to form.
From their research, the scientists conclude that toxins generated by harmful algal blooms most likely poisoned many ocean-going vertebrates near Cerro Ballena in the late Miocene (5-11 million years ago) through ingestion of contaminated prey or inhalation, causing relatively rapid death at sea. Their carcasses then floated toward the coast, where they were washed into a tidal flat by waves. Once stranded on the tidal flat, the dead or dying animals were protected from marine scavengers, and there were no large-land scavengers in South America at this time. Eventually, the carcasses were buried by sand. Because there are four layers at Cerro Ballena, this pathway from sea to land occurred four different times during a period of 10,000 to 16,000 years in the same area.
“Cerro Ballena is the densest site for individual fossil whales and other extinct marine mammals in entire world, putting it on par with the La Brea Tar Pits or Dinosaur National Monument in the U.S.,” Pyenson said. “The site preserves marine predators that are familiar to modern eyes, like large whales and seals. However, it also preserves extinct and bizarre marine mammals, including walrus-like whales and aquatic sloths. In this way, the site is an amazing and rare snapshot of ancient marine ecosystems along the coast of South America.”
3-D Technology at Cerro Ballena
Because the site was soon to be covered by the Pan-American Highway, time was very limited for the researchers. A major solution came in the form of 3-D technology. Pyenson brought a team of Smithsonian 3-D imaging experts to Chile, who spent a week scanning the entire dig site.
Although all the fossils found from 2010 to 2013 have been moved to museums in the Chilean cities of Caldera and Santiago, the Smithsonian has archived the digital data, including the 3-D scans, from the site at cerroballena.si.edu. There, anyone can download or interact with 3-D models of the fossil whale skeletons, scan Google Earth maps of the excavation quarries, look at a vast collection of high-resolution field photos and videos or take 360-degree tours of the site.
The enormous wealth of fossils that the team examined represents only a fraction of the potential at Cerro Ballena, which remains unexcavated. The scientists conservatively estimate that the entire area preserves several hundred fossil marine mammal skeletons, awaiting discovery. Pyenson’s colleagues at the Universidad de Chile in Santiago are actively working to create a research station near the fossils of Cerro Ballena so that those that have been collected and those still covered by sediments can be protected for posterity.