Exploring Prehistoric Life

Archaeopteryx Was Active Flyer, Paleontologists Say

Thursday, March 15, 2018

An artist’s impression of what Archaeopteryx lithographica, one of the earliest known birds, would have looked like in flight. Image credit: Carl Buell / Nicholas Longrich.

Archaeopteryx is an iconic fossil species with feathered wings from the Late Jurassic of Germany. The question of whether this dino-bird was an elaborately feathered ground dweller, a glider, or an active flyer has fascinated paleontologists for many years. European Synchrotron Radiation Facility researcher Dennis Voeten and colleagues have now analyzed new data from three Archaeopteryx specimens and found that the wing bones of the ancient creature were shaped for incidental active flight, but not for the advanced style of flying mastered by modern-day birds.

Was Archaeopteryx capable of flying, and if so, how? Although it is common knowledge that modern-day birds descended from extinct dinosaurs, many questions on their early evolution and the development of avian flight remain unanswered.

Traditional research methods have thus far been unable to answer the question whether Archaeopteryx flew or not.

Using synchrotron microtomography to probe inside Archaeopteryx fossils, Dr. Voeten and co-authors shed new light on this earliest of birds.

Reconstructing extinct behavior poses substantial challenges for paleontologists, especially when it comes to enigmatic animals such as Archaeopteryx. This well-preserved fossil species shows a mosaic anatomy that illustrates the close family relations between extinct raptorial dinosaurs and the birds.

Most modern bird skeletons are highly specialized for powered flight, yet many of their characteristic adaptations in particularly the shoulder are absent in Archaeopteryx specimens.

Although its feathered wings resemble those of modern birds flying overhead every day, the primitive shoulder structure is incompatible with the modern avian wing beat cycle.

“The cross-sectional architecture of limb bones is strongly influenced by evolutionary adaptation towards optimal strength at minimal mass, and functional adaptation to the forces experienced during life,” said Professor Jorge Cubo, from the Sorbonne University, France.

“By statistically comparing the bones of living animals that engage in observable habits with those of cryptic fossils, it is possible to bring new information into an old discussion,” added Dr. Sophie Sanchez, from Uppsala University, Sweden.

Archaeopteryx skeletons are preserved in and on limestone slabs that reveal only part of their morphology. Since these fossils are among the most valuable in the world, invasive probing to reveal obscured or internal structures is therefore highly discouraged.

“Fortunately, today it is no longer necessary to damage precious fossils,” said Dr. Paul Tafforeau, of the European Synchrotron Radiation Facility.

“The exceptional sensitivity of X-ray imaging techniques for investigating large specimens offers harmless microscopic insight into fossil bones and allows virtual 3D reconstructions of extraordinary quality.”

Scanning data unexpectedly revealed that Archaeopteryx’s wing bones, contrary to its shoulder girdle, shared important adaptations with those of modern flying birds.

“We focused on the middle part of the arm bones because we knew those sections contain clear flight-related signals in birds,” said Dr. Emmanuel de Margerie, from CNRS, France.

“We immediately noticed that the bone walls of Archaeopteryx were much thinner than those of earthbound dinosaurs but looked a lot like conventional bird bones,” Dr. Voeten said.

“Data analysis furthermore demonstrated that the bones of Archaeopteryx plot closest to those of birds like pheasants that occasionally use active flight to cross barriers or dodge predators, but not to those of gliding and soaring forms such as many birds of prey and some seabirds that are optimized for enduring flight.”

“We know that the region around Solnhofen in southeastern Germany was a tropical archipelago, and such an environment appears highly suitable for island hopping or escape flight,” said Dr. Martin Röper, from the Bürgermeister-Müller-Museum and the Bayerische Staatssammlung für Paläontologie und Geologie, Germany.

Archaeopteryx shared the Jurassic skies with primitive pterosaurs that would ultimately evolve into the gigantic pterosaurs of the Cretaceous. We found similar differences in wing bone geometry between primitive and advanced pterosaurs as those between actively flying and soaring birds,” said Dr. Vincent Beyrand, from the European Synchrotron Radiation Facility.

The findings are published in the journal Nature Communications.


Dennis F.A.E. Voeten et al. 2018. Wing bone geometry reveals active flight in ArchaeopteryxNature Communications 9, article number: 923; doi: 10.1038/s41467-018-03296-8

Source: www.sci-news.com

Flightless Bird Extinct for More Than 700 Years Can be Brought Back to Life, Say Scientists

Wednesday, February 28, 2018

Museum host shows Singapore's Prime Minister Lee Hsien Loong a giant Moa bird during a visit to Te Papa Museum in Wellington. [Representational Image]

The little bush moa inhabited parts of New Zealand and went extinct in the late 13th century as a result of overhunting.

Scientists are a step closer to bringing back a species of flightless bird that has been extinct for almost 700 years. The little bush moa that inhabited parts of New Zealand went abruptly extinct as a result of overhunting in the late 13th century.

A team of researchers from Harvard University has assembled a nearly-complete genome of the extinct moa by extracting ancient DNA from the toe bone of a moa specimen held at the Royal Ontario Museum in Toronto, Canada.

The scientists now believe that they are closer to the goal of "de-extinction" — the vanished species can be brought back to life by slipping the genome into the egg of a living species, Statnews reported.

"High throughput sequencing has revolutionized the field of ancient DNA (aDNA) by facilitating recovery of nuclear DNA for greater inference of evolutionary processes of extinct species than is possible from mitochondrial DNA alone," according to the study.

Credit: J. Erxleben, Transactions of the Zoological Society of London v. 11, Wikimedia

The little bush moa was a part of the palaeognathae clade of birds and birds, and those like the kiwi, ostrich, and emu were considered its cousins. There were nine species of the moa but all of them are extinct now.

They roamed in the forests of the North and South Islands of New Zealand before they became extinct, the NZ Herald said. They were on an average four feet tall and weighed about 66 pounds.

Experts believe that the Harvard researchers' work could make it easier to bring back the long-lost species from extinction.

"The fact that they could get a genome from a little bush moa toe is a big deal since now we might be able to use their data to do other extinct bird species," Ben Novak, lead scientist at non-profit conservation group Revive and Restore, told Statnews.

"De-extinction could be useful for inspiring new science and could be beneficial for conservation if we ensure it doesn't reduce existing conservation resources," University of Queensland scientist Hugh Possingham said in a statement.

"However, in general, it is best if we focus on the many species that need our help now," he added.

Source: www.ibtimes.co.in

Fossil Turtle Species, 5.5 Million Years Old, Sheds Light on Invasive Modern Relatives

Wednesday, February 28, 2018

Though initially found in pieces, Gray Fossil Site preparator Shawn Haugrud was able to glue the shell of this species back together, enabling Penn's Steven Jasinski to complete an analysis of the turle. Jasinski named the species in Haugrud's honor. Credit: Image courtesy of University of Pennsylvania

A University of Pennsylvania paleontologist has described a 5.5 million-year-old fossil species of turtle from eastern Tennessee. It represents a new species of the genus Trachemys, commonly known as sliders, which are frequently kept as pets today.

Steven Jasinski, author of the new study, is a doctoral student at the University of Pennsylvania and acting curator of paleontology and geology at the State Museum of Pennsylvania. He is completing his Ph.D. at Penn under Peter Dodson, a professor of paleontology in the Department of Earth and Environmental Science in the School of Arts and Sciences and a professor of anatomy in the School of Veterinary Medicine.

The study investigated a fossil turtle found around the Miocene - Pliocene boundary in the Gray Fossil Site, an area rich with fossils in eastern Tennessee near East Tennessee State University, where Jasinski completed his master's degree. The site represents an ancient sinkhole surrounded by a forest from which dozens of fossil animal species have been characterized, including new species of red panda, Eurasian badger, kinosternid turtle, and colubrid snake.

Thorough examination of the dozens of turtle fossils from the site revealed important differences between this turtle and other known fossil and living species. Jasinski named the fossil turtle Trachemys haugrudi, after Shawn Haugrud, the lab and field manager and lead preparer at the Gray Fossil Site.

"Shawn has spent an incredible number of hours working on these specimens," Jasinski said. "He cleaned and prepared the fossils and was able to essentially glue this turtle back to life, giving me numerous nearly complete turtle shells to use in this research. Without all that time and effort, I wouldn't have been able to determine nearly as much about this turtle as I did.

"Shawn also didn't do this work alone, as numerous other people including volunteers worked on these fossils and got them prepared so that I could complete my research. They really did all the hard work, and I was then able to determine why it was new and what its implications are" he said.

Turtles are best known for their shells, and indeed it is this feature of their anatomy that is commonly found as fossils. Yet the fossil shells are typically found in broken pieces. Often gaps or holes remain, or only single small pieces are found, and the whole must be inferred from other information, including other fossil and living creatures.

"It is extremely rare to get more complete fossils," Jasinski said, "but Trachemys haugrudi, commonly called Haugrud's slider turtle, provides me with dozens of shells, and several are nearly complete."

Haugrud's slider turtle was a fairly small turtle, not more than approximately 10 inches (25 cm) in total shell length, smaller than the modern-day red-eared slider turtle, Trachemys scripta elegans. Red-eared slider turtles are commonly purchased as pets, though they can grow large, and some owners release them into the wild. As a result, though native to the southeastern United States, red-eared sliders have become one of the most invasive animal species in the world today, found on every continent except Antarctica.

"People tend to see all turtles as similar and release them into whatever pond or river is close by when they no longer want to care for them," Jasinski said. "Once released, however, they often outcompete native species. It is a problem that scientists are still dealing with."

As part of the study, Jasinski sought to determine where Trachemys haugrudi was positioned in the evolution of similar turtles both within the genus and in related genera. He performed a phylogenetic analysis, a method that compares shapes and features of different species to determine how similar or dissimilar and therefore how closely related they may be. He found Haugrud's to be most closely related to a group of fossil Trachemys turtles from Florida and next most closely related to a distinct group of fossil Trachemys from the midwestern U.S. Together, these fossil Trachemys form a closely related group situated within other still-living species of Trachemys.

Today, distinct, closely-related groups of Trachemys species dwell in Mexico, Central and South America, and the Caribbean. Jasinski's investigation, along with other information from previous studies, indicates that one group evolved in Mexico and Central and South America and evolved into different species within this geographic area, and another group evolved separately in the Caribbean.

Species from the U.S., including the red-eared slider turtle, are found near the base of their "branch" of the Trachemys family tree; their fossil ancestors are still waiting to be discovered. The fossil Trachemys species in Jasinski's analysis are on a distinct part of the Trachemys tree, and current understanding suggests that they did not give rise to the modern species living today.

The findings imply that there was once much greater diversity in Trachemys turtles than exists today. It seems that many of the ancient slider species died out without leaving any direct descendents, perhaps because they lacked the ability to adapt to different environments.

"While Trachemys turtle species are considered plastic, implying they can adapt to and live in many environments, this adaptive lifestyle may be a relatively newer characteristic of these turtles," Jasinski said. "More fossils are needed to better understand if this aspect of their evolution is a recent addition."

To get a handle on invasive turtles, understanding more about their ancient relatives could only be helpful, Jasinski said.

"Trachemys haugrudi helps provide more information on Trachemys and begins to offer us insights into the evolution of an animal that has become a problematic invader in many areas of the world," he said. "Understanding how something evolved into its present form may help us understand why an animal is so adaptive and good at invading new areas and outcompeting native species. If we can see that Trachemys today are especially adaptive because evolution has allowed them to become more generalized through time, we can use that information to determine where they may invade, what species they may outcompete and what we can do to counteract those invasions or help native species compete against them."

Jasinski is undertaking further study into the fossil species of not only Trachemys but other turtles within the family Emydidae, which includes Trachemys. He hopes that further data and fossils will help shed light on other turtle species and provide a clearer understanding of the evolution of this group of mainly New World turtles.

The study was supported by the National Science Foundation (Grant 0958985 to Steven Wallace and the Gray Fossil Site), Office of Research and Sponsored Programs at East Tennessee State University, Don Sundquist Center of Excellence in Paleontology, State Museum of Pennsylvania, and Department of Earth and Environmental Science at the University of Pennsylvania.

Story Source:

Materials provided by University of PennsylvaniaNote: Content may be edited for style and length.

Journal Reference:

  1. Steven E. Jasinski. A new slider turtle (Testudines: Emydidae: Deirochelyinae: Trachemys) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the evolution of the deirochelyinesPeerJ, 2018; 6: e4338 DOI: 10.7717/peerj.4338

Source: www.sciencedaily.com

A Rich Collection of Triassic Fossils Found at Bears Ears

Monday, February 26, 2018

Paleontologists excavate a phytosaur fossil in what was Bears Ears National Monument in September 2017. The site turns out to harbor a rich deposit of Late Triassic fossils in the Chinle Formation.  (Photo courtesy of Robert Gay)

Paleontologist Robert Gay’s quest to find the fossilized remains of an ancient phytosaur, a primitive ancestor to crocodiles, turned into something much larger last summer when he came upon a major trove of Triassic fossils on public lands recently stripped from Utah’s Bears Ears National Monument.

But Gay’s find also is significant for other reasons that speak to the vulnerability of fossil deposits in Utah and elsewhere to looting and vandalism, especially those near roads like the site he dug with permission and funding from the Bureau of Land Management.

“This site [on the western side of the former monument] is pretty spectacular,” the scholar told The Salt Lake Tribune on Friday.

“It’s an entire bone bed, it is the largest and densest Triassic bone bed in the state of Utah. It is higher density than some of the more famous Jurassic sites,” said Gay, who presented his findings Feb. 16 at the annual meeting of the Western Association of Vertebrate Paleontologists in St. George.

“There are decades of work at this site,” said Gay, who called the deposits “the Triassic equivalent of Dinosaur National Monument,” famed for later Jurassic fossils.

Gay discovered articulated phytosaur remains, with fossilized bones found together, during survey work in 2016 in Chinle Formation, which dates back 217 to 223 million years. He returned the following September to recover the bones in a project conducted in conjunction with the Museums of Western Colorado.

But as Gay’s work progressed, he said, his team uncovered the front end of a ancient crocodile’s snout, but the cranium and neck were missing. Plaster residue clung to the sandstone, a tell-tale sign that someone had looted the site, said Gay, who serves as education director for the Colorado Canyons Association in Grand Junction.

He reported the theft to the BLM, which had some good news for him.

Nearly a decade earlier, the culprit had turned in the purloined skull, missing a snout, to Arizona’s Petrified Forest National Monument, according to Bill Parker, the monument paleontologist who received the skull. Parker had only recently transported the skull to BLM paleontologists in Moab, who in turn delivered it to the Natural History Museum of Utah for curation.

“It was complete serendipity that three weeks after I dropped it off, I got a call from the BLM saying they thought someone found the rest of it,” Parker said.

“It’s a good story because that doesn’t always happen,” he said.

In September 2008, the person who looted the fossil brought it to Parker after finding it in his garage. He admitted he excavated if from a particular canyon in San Juan County — without proper permits.

“I made a decision, because it was supposedly from BLM land, to accept it,” Parker said. “So he signed it over to us. I contacted Utah state geologist. At the time there was no proof of where it came from, the person wasn’t held. He has since moved on and who knows where they are.”

Information submitted by a BLM paleontologist to the St. George conference indicates the illegal excavator was a “volunteer at a major regional museum,” who turned in the specimen after partial preparation.

“This situation shows the need for increased education, monitoring, and protection around paleontological resources and highlights the vulnerability of fossil resources that remain un-excavated across the Bears Ears region,” the BLM report said.

It was only through a “rare combination of circumstances,” the BLM said, that the fossil’s origins were rediscovered. That, the report said, “is not the usual situation for looted fossils, which are often never recovered or recovered without their context, making this case a poignant reminder of what can be lost during looting.”

Parker and his colleague Larkin McCormack are preparing a paper on the stolen half of the specimen — believed to be from the ancient species Pravusuchus hortus — for scientific publication. In the meantime, he hopes the two specimens can be reunited, but that, it turns out, is easier said than done.

Gay’s specimen is currently undergoing preparation at St. George’s Dinosaur Discovery Site at Johnson Farm, which is helping manage the excavation. The bones will eventually be curated at the Museums of Western Colorado, which hopes to put them on display.

That organization, which has a paleontology museum in Fruita, wants to obtain the stolen half of the skeleton so the whole thing can be studied as a single unit.

“We are trying to figure out a way to keep the site and specimens together between our two museums,” said paleontology curator Julia McHugh. “There’s a lot of logistics and paperwork involved, so we haven’t quite nailed down how we are going to do that.”

“From the perspective of someone doing research,” McHugh said, “it’s not in their best interests to have the site divvied up between two museums.

She said she agrees the new Bears Ears fossil site is special and could shed new light on the Late Triassic, a period when some big reptiles went extinct and dinosaurs rose to rule the world during the Jurassic.

“It’s a really good site, has some good bone in it. It has some good diversity in it,” said McHugh, whose museum is also exploring Triassic sites in New Mexico. The Bears Ears locale appears to also harbor remains of an armored plant-eating crocodilian, known as aetosaur.

“One of the great things about the Late Triassic is you have a big turn over in ecosystems. You go from a world dominated by large amphibians, large crocodilian predators, herbivore, and you have the rise of dinosaurs coinciding with this,” McHugh said.

“As these lineages change over for who’s in charge of the ecosystem, you get a window into how evolution is working and how changes in climate are driving evolution,” she said. “Because we have a sporadic fossil record, any time we get a new site with a lot of good material, it’s really exciting because it is going to tell us things we don’t know yet.”

Conservationists have heavily promoted Gay’s discovery because it highlights what they say was the shortsightedness of President Donald Trump’s decision to shrink the Bears Ears monument, a move that is being challenged in court.

“While a discovery of this magnitude certainly is a welcome surprise, protecting such resources was the very purpose of Bears Ears National Monument,” said Scott Miller of the Wilderness Society, an environmental group.

“That President Trump acted to revoke protections for these lands is outrageous, and that he did so despite the Department of the Interior knowing of this amazing discovery is even more shocking,” Miller said. “I hope the courts will act quickly to restore protections for Bears Ears National Monument before any more fossils are looted from the area and lost to science.”

Whatever the outcome of the court case, however, the fossils will remain under the jurisdiction of the Paleontological Resources Protection Act, a 2009 law that carries criminal penalties for those who loot fossils from public lands.

Source: www.sltrib.com

Fossil Moth Scales Can Uncover Prehistoric Secrets, Scientists Say

Monday, February 26, 2018

A well-preserved scale extracted from a lake sediment core. Image credit: Montoro Girona et al, doi: 10.3389/fevo.2018.00002.

A groundbreaking new technique for studying lake sediments can tell scientists more about the frequency and intensity of past and future insect epidemics, their impact on the forest environment and how they are linked to climate change.

“This is an exciting discovery, which will greatly increase our knowledge of prehistoric forest ecosystems,” said Dr. Miguel Montoro Girona, a researcher at the Swedish University of Agricultural Sciences in Umeå, Sweden.

“It is comparable to the fossil pollen and charcoal markers in sediments, which revolutionized prehistoric research to provide information on plants, climate and forest fires going back thousands of years. Our new method can be applied to many ecosystems where moths and butterflies have a marked influence on the landscape.”

Moths are one of the most widespread and recognizable insects in the world.

In the boreal forests of North America, which are mainly comprised of coniferous, evergreen trees, the larva of one moth species — the spruce budworm (Choristoneura fumiferana) — can periodically cause severe and widespread damage. This leads to millions of dollars of lost revenue to the forest-based economy.

It was during a routine observation of one of these outbreaks that Dr. Montoro Girona and co-authors had a Eureka! moment.

“Together with an insect specialist, we recently identified a ‘strange’ structure in a colleague’s lake-water sample, which turned out to be a scale from a moth wing,” said Dr. Hubert Morin, a researcher at the Québec University, Canada.

“Afterwards, during a spruce budworm outbreak, I noticed the lakes were covered in dead moths. Knowing they are made from a material that is likely to be well-preserved in the sediments of lakes, I realized they had the potential to provide information about these swarms going back thousands of years.”

This hunch turned out to be true. Taking a 5-m-long core of sediment from a forest lake near Québec, which represented 10,000 years’ worth of sediment deposit, the team spent five years perfecting their method of extracting, examining and counting moth scales under the microscope from each sediment layer.

“Our analysis revealed peaks of moth scales that corresponded to known periods of insect outbreak,” said Dr. Lionel Navarro, also from the Québec University.

“This means we can work out when these epidemics occurred before records began.”

“This new method will be of enormous help to future research in areas as wide as ecology and evolution, biodiversity conservation, climate change and forestry.”

The findings were published in the journal Frontiers in Ecology and Evolution.


Miguel Montoro Girona et al. A Secret Hidden in the Sediments: Lepidoptera Scales. Front. Ecol. Evol, published online January 26, 2018; doi: 10.3389/fevo.2018.00002

Source: www.sci-news.com

Scientists Predict How Dinosaurs Like Tyrannosaurus Rex Pursued Their Prey

Friday, February 23, 2018

Tyrannosaurus rex as an example of dinosaur anatomy and locomotion.a, The basic skeletal components and joints of the hindlimb. Only the third toe is shown for clarity. b, Redundancy allows the limb to assume a range of potential hip heights. c, For each position of the hip with respect to the foot, a spectrum of internal configurations is possible.

The mechanics of a dinosaur’s massive body can be hard to understand because scientists cannot watch them in motion, but birds are helping to solve the mystery that cannot be unraveled with fossils alone.

Although the dinosaur era ended with a devastating asteroid impact about 66 million years ago, birds are descendants of the prehistoric beasts. A team of researchers studied 12 species of birds of varying sizes that live on the ground and run, including the birds’ motions and how much force their feet exert upon the ground when they move.

Birds show “a highly continuous locomotor repertoire compared to humans, where discrete ‘walking’ and ‘running’ gaits are not easily distinguished,” according to the study, published in the journal PLOS One.

In other words, their change from walking to running is more of a flow, while in humans a change between the two modes is more stark.

Researchers had previously documented that flow from walking to running before, and the new study backs up that model.

The scientists say their observations are a window into how bipedal dinosaurs — the ones that stood on their hind legs — may have walked and run.

The famous Tyrannosaurus rex is one example of a bipedal dinosaur, as is the Velociraptor. The quadrupedals, or the dinosaurs that walked on four legs, included popular ones like the Triceratops and the Stegosaurus.

“A perennial question of interest for paleontologists is how extinct animals appeared and behaved when they were alive,” the authors wrote in their paper. “One way of better understanding how extinct theropods moved is to examine locomotion in extant theropods, birds, because birds retain many (homologous) anatomical similarities to their ancestors.”

The scientists collected information by video recording the birds as they ran along racetracks, according to journal publisher Public Library of Science. Plates in the ground measured the force the birds exerted with their feet.

The team crunched its data on running birds and how their locomotion changed with their speed and size to create models that might predict how the dinosaurs moved.

Those models have the potential to change how scientists interpret dinosaur footprints.

“At equivalent relative speeds, a small theropod will be moving in a decidedly different fashion to a large theropod,” according to the study. “This in turn raises concerns about the accuracy with which palaeontologists can reliably interpret fossil theropod footprints, in terms of inferring the posture and ‘gait’ of the trackmaker.”

Source: www.ibtimes.com

Now, Scientists Think They Know Why Most Ankylosaurs Were Fossilized Belly Up.

Friday, February 23, 2018

Researchers have worked out why ankylosaur fossils are usually discovered upside-down. DEAN MOUHTAROPOULOS/GETTY IMAGES

Ankylosaurs are odd-looking, even by dinosaur standards: They’re squat and fat, with armored backs and, usually, tail clubs. But for many scientists, there’s another reason these creatures stand out—most are fossilized upside-down. The reason for this strange orientation was a mystery for decades, but thanks to an unusual collaboration between paleontologists and armadillo experts, we may finally have an answer—and it all comes down to bloated, floating dinosaur carcasses.

Since the 1930s, paleontologists have suspected something funny about ankylosaurs’ physiology or behavior led to their belly-up preservation. But although several theories have been put forward, none has been proved. So Jordan Mallon, a dinosaur paleontologist at the Canadian Museum of Nature in Ottawa, decided to test each of these theories and try to solve the mystery.

First, Mallon’s team wanted to make sure that the common wisdom on ankylosaur orientation wasn’t just an old wives’ tale. After examining 36 ankylosaurs from the province of Alberta in Canada, along with photos and field notes of the excavations, they found that 26 were discovered upside-down—more than would be expected by chance.
The team then turned its attention to the four theories. One, that ankylosaurs simply fell down hills and ended up on their backs, was easy to discount: “If ankylosaurs were universally clumsy, then you wouldn’t expect them to stick around for 100 million years,” Mallon says. Likewise, the researchers found no support for the theory that predators flipped ankylosaurs over to access their delicious underbellies. Teeth marks were only present on one of the specimens they examined.

The “armadillo roadkill model” proved trickier. Because armadillos found on the side of the road supposedly swell up with gases as they decompose, tipping them onto their backs, the same could be true of ankylosaurs. Mallon enlisted the help of armadillo experts Colleen McDonough and Jim Loughry at Valdosta State University in Georgia who spent 3 months surveying armadillo carcasses by the side of the road. The husband-and-wife team would set off at sunrise, McDonough says, before roadkill had become “pancaked” or had been pecked to pieces by vultures. With help from family and friends who sent tip-offs about the location of fresh carcasses (“we call them our network,” McDonough says), the duo recorded the orientation of 174 armadillos—and found no indication that they regularly ended up on their backs.

On the roads, dead armadillos could be moved into their final resting places by scavengers or vehicles, so the scientists also decided to bring some fresh carcasses home, leaving them in their garden to see what would happen as they decomposed. In the paper, the pair thanks their understanding neighbors. “There was a prevalent stench coming from the corner of our yard where we meet three other yards—and no one said a word,” McDonough says. But none of the armadillos placed on their stomachs rolled over, again suggesting that this model didn’t hold up to scrutiny.

Finally, the researchers examined the “bloat-and-float” model, which proposes that the bodies of ankylosaurs got washed into rivers or the sea, where they bloated and became unstable, flipping upside-down and eventually sinking or being deposited in the river bank. Mallon’s co-author Donald Henderson at the Royal Tyrrell Museum in Drumheller, Canada, created 3D digital models representing the two families of ankylosaur, the ankylosaurids and the nodosaurids. The team fleshed these out with estimations of the dinosaurs’ physical characteristics like lung capacity and bone density. They also created bloated versions of the same dinosaurs, inflating the animals’ stomachs like balloons. They then placed the models in virtual water, and looked at how easily they tipped over.

The nodosaurid model was very unstable: Tipping it merely 1° caused it to turn upside-down, whether it was bloated or not. The ankylosaurid was more resistant, requiring a much larger tilt before it would flip over. Still, says Mallon, a big wave or a predator could easily be enough to force the dinosaur onto its back, especially after bloating. That meant the bloat-and-float model was the only theory that held any water, the team reports this month in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Victoria Arbour, a vertebrate paleontologist at the Royal Ontario Museum and the University of Toronto in Canada who was not involved in the research, says that the study “reasonably seals the deal” on the long-standing mystery. She adds that she admires the scientists’ approach to the research. “I always really like it in paleontology when we can use totally independent lines of evidence like that to tell a bigger story,” she says. Mallon agrees: “It’s pretty rare that the scientific method plays out so cleanly in practice, but I think this is a nice case where it does.”

Source: www.sciencemag.org

Trachemys haugrudi: New Fossil Turtle Species Discovered in Tennessee

Wednesday, February 28, 2018

Trachemys haugrudi represents a new species of fossil turtle that lived in what is now eastern Tennessee more than 5.5 million years ago. Image credit: Mary P. Williams.

University of Pennsylvania paleontologist Steven Jasinski has announced the discovery of a previously unknown species of fossil turtle in the Gray Fossil Site, an area rich with fossils in eastern Tennessee, the United States.

Named Trachemys haugrudi, the ancient reptile was a fairly small turtle, not more than 10 inches (25 cm) in total shell length, smaller than the extant red-eared slider turtle (Trachemys scripta elegans).

It lived in what is now eastern Tennessee around the Miocene-Pliocene boundary, about 5.5 million years ago.

The Gray Fossil Site represents an ancient sinkhole surrounded by a forest from which dozens of fossil animal species have been characterized, including new species of red panda, Eurasian badger, kinosternid turtle, and colubrid snake.

Thorough examination of the dozens of turtle fossils from the site revealed important differences between Trachemys haugrudi and other known fossil and living species.

“Turtles are best known for their shells, and indeed it is this feature of their anatomy that is commonly found as fossils. Yet the fossil shells are typically found in broken pieces,” Jasinski explained.

“Often gaps or holes remain, or only single small pieces are found, and the whole must be inferred from other information, including other fossil and living creatures.”

“It is extremely rare to get more complete fossils, but Trachemys haugrudi, commonly called Haugrud’s slider turtle, provides me with dozens of shells, and several are nearly complete.”

As part of the study, Jasinski sought to determine where Trachemys haugrudiwas positioned in the evolution of similar turtles both within the genus and in related genera.

The scientist found Trachemys haugrudi to be most closely related to a group of fossil Trachemys turtles from Florida and next most closely related to a distinct group of fossil Trachemys from the Midwestern United States.

Together, these fossil Trachemys form a closely related group situated within other still-living species of Trachemys.

Today, distinct, closely-related groups of Trachemys species dwell in Mexico, Central and South America, and the Caribbean. Jasinski’s investigation, along with other information from previous studies, indicates that one group evolved in Mexico and Central and South America and evolved into different species within this geographic area, and another group evolved separately in the Caribbean.

Species from the United States, including the red-eared slider turtle, are found near the base of their ‘branch’ of the Trachemys family tree; their fossil ancestors are still waiting to be discovered.

The fossil Trachemys species in this study are on a distinct part of the Trachemys tree, and current understanding suggests that they did not give rise to the modern species living today.

The findings imply that there was once much greater diversity in Trachemysturtles than exists today.

It seems that many of the ancient slider species died out without leaving any direct descendents, perhaps because they lacked the ability to adapt to different environments.

“While Trachemys turtle species are considered plastic, implying they can adapt to and live in many environments, this adaptive lifestyle may be a relatively newer characteristic of these turtles,” Jasinski explained.

“More fossils are needed to better understand if this aspect of their evolution is a recent addition.”

“To get a handle on invasive turtles, understanding more about their ancient relatives could only be helpful.”

paper reporting this discovery is published in the journal PeerJ.


S.E. Jasinski. 2018. A new slider turtle (Testudines: Emydidae: Deirochelyinae: Trachemys) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the evolution of the deirochelyines. PeerJ 6: e4338; doi: 10.7717/peerj.4338

Source: www.sci-news.com

Megalodon: The Terror of The Deep

Friday, March 9, 2018

Megalodon Was Three Times As Long As The Largest Great White

Megalodon (Carcharocles megalodon), meaning "big tooth," is an extinct species of shark that lived approximately 23 to 2.6 million years ago (mya), during the Early Miocene to the end of the Pliocene. There had been some debate regarding the taxonomy of megalodon: some researchers argued that it was of the family Lamnidae and closely related to the great white shark (Carcharodon carcharias), while others argued that it belonged to the extinct family Otodontidae; presently, there is near unanimous consensus that the latter view is correct. Its genus placement is still debated, authors placing it in either CarcharoclesMegaselachusOtodus, or Procarcharodon. The shark has made appearances in several media, such as the Discovery Channel's docufiction Megalodon: The Monster Shark Lives.

Megalodon size

Megalodon is regarded as one of the largest and most powerful predators in vertebrate history, and likely had a profound impact on the structure of marine communities.

Fossil remains suggest that this giant shark reached a maximum length of 50–70 feet, and also affirm that it had a cosmopolitan distribution. Scientists suggest that Megalodon looked like a stockier version of the great white shark. 

When it was alive, Megalodons were the largest sharks to have ever lived and had a fearsome appetite, according to the Florida Museum of Natural History. By some estimates, Megalodons ate about 2,500 pounds of food every day, including fish and whales.

Fossils show that the sharks could have ingested several humans at the same time.

The sharks had 46 front row teeth, 24 in the upper jaw and 22 in the lower jaw. Most sharks have at least six rows of teeth, and a Megalodon had about 276 teeth at any given time.

Scientists suggest that megalodon looked like a stockier version of the great white shark, though it may have looked similar to the basking shark (Cetorhinus maximus) or the sand tiger shark (Carcharias taurus). Regarded as one of the largest and most powerful fish to have ever lived, fossil remains of megalodon suggest that this giant shark reached a length of 18 meters (59 ft). Their large jaws could exert a bite force of up to 108,500 to 182,200 newtons (24,390 to 40,960 lbf). Their teeth were thick and robust, built for grabbing prey and breaking bone.

Locations of megalodon fossil discoveries, yellow from the Pliocene and blue from the Miocene

Megalodon probably had a profound impact on the structure of marine communities. The fossil record indicates that it had a cosmopolitan distribution. It probably targeted large prey, such as whales, seals, and giant turtles. Juveniles inhabited warm coastal waters where they would feed on fish and small whales. Unlike the great white, which attacks prey from the soft underside, megalodon probably used its strong jaws to break through the chest cavity and puncture the heart and lungs of its prey.

The animal faced competition from whale-eating cetaceans, such as Livyatan and ancient killer whales (Orcinus citoniensis), which likely contributed to its extinction. As it preferred warmer waters, it is thought that oceanic cooling associated with the onset of the ice ages, coupled with the lowering of sea levels and resulting loss of suitable nursery areas, may have also contributed to its decline. A reduction in the diversity of baleen whales and a shift in their distribution toward polar regions may have reduced megalodon's primary food source. The extinction of the shark appeared to affect other animals; for example, the size of baleen whales increased significantly after the shark had disappeared.

Megalodon tooth with two great white shark teeth

The question for researchers is, are they still out there in the ocean depths?

Interestingly enough, there are many who refuse to believe that the megalodon shark is indeed extinct. Skeptics feel as if the megalodon shark may possibly be in existence deep down in the ocean. While it is true that we have not explored every inch of the world’s oceans, and it is likely that there are undiscovered species living in the depths of the waters, the belief that the megalodon shark may still be alive today has yet to be proven. Sharks are known for shedding hundreds of teeth on a regular basis; if the megalodon shark was still alive, they would be expected to shed the most teeth out of all of these sharks. Every megalodon tooth that has been found is ancient. Until a fresh megalodon tooth, a “megatooth” shark sighting, or some other form of proof has been presented, it is determined that this ancient shark is most definitely extinct.

This shark species has become increasingly popular because the Discovery Channel airs programs that claim it could still exist.

Many scientists say that the shark species definitely exist, while many deride Discovery for airing such programs.

Source: www.wikipedia.org

Early Cretaceous Bird Fossil Sheds New Light on Avian Evolution

Wednesday, March 7, 2018

Artist impression of a juvenile enantiornithe bird. Image credit: Raúl Martín.

The tiny fossil of a juvenile enantiornithe bird from the Early Cretaceous La Huérguina Formation of Spain is helping paleontologists understand how early birds came into the world in the age of dinosaurs.

The 127-million-year-old fossil is a chick from a group of prehistoric birds called Enantiornithes.

The specimen consists of a nearly complete skeleton; the feet, most of its hands, and the tip of the tail are the only missing parts.

It measures less than 2 inches (5 cm) and would have weighed just 10 g when it was alive. It is amongst the smallest known Mesozoic avian fossils ever discovered.

What makes this fossil so important and unique is the fact it died not long after its birth. This is a critical stage in a bird’s skeletal formation. That means this bird’s extremely short life has given paleontologists a rare chance to analyze the species’ bone structure and development.

“Studying and analyzing ossification — the process of bone development — can explain a lot about a young bird’s life,” said University of Manchester researcher Dr. Fabien Knoll and colleagues.

“It can help us understand everything from whether it could fly or if it needed to stay with its parents after hatching or could survive on its own.”

“The evolutionary diversification of birds has resulted in a wide range of hatchling developmental strategies and important differences in their growth rates. By analyzing bone development we can look at a whole host of evolutionary traits,” Dr. Knoll said.

“With the fossil being so small we used synchrotron radiation to picture the tiny specimen at a ‘submicron’ level, observing the bones’ microstructures in extreme detail.”

Phosphorous mapping image and photo of the specimen. Image credit: Fabien Knoll.

The scientists found the baby bird’s sternum (breastplate bone) was still largely made of cartilage and had not yet developed into hard, solid bone when it died, meaning it wouldn’t have been able to fly.

The patterns of ossification observed in this and the other few very young enantiornithine birds known to date also suggest that the developmental strategies of this particular group of ancient avians may have been more diverse than previously thought.

“However, its lack of bone development doesn’t necessarily mean the hatchling was over reliant on its parents for care and feeding, a trait known as being ‘altricial’,” the study authors said.

“Modern day species like love birds are highly dependent on their parents when born. Others, like chickens, are highly independent, which is known as ‘precocial.’ Although, this is not a black-and-white issue, but rather a spectrum, hence the difficulty in clarifying the developmental strategies of long gone bird species.”

“This new discovery, together with others from around the world, allows us to peek into the world of ancient birds that lived during the age of dinosaurs. It is amazing to realize how many of the features we see among living birds had already been developed more than 100 million years ago,” said Dr. Luis Chiappe, from the LA Museum of Natural History.

The research is published in the journal Nature Communications.


Fabien Knoll et al. 2018. A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds. Nature Communications 9, article number: 937; doi: 10.1038/s41467-018-03295-9

Source: www.sci-news.com