WFS news: World’s longest sauropod dinosaur track way brought to light

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In 2009, the world’s largest dinosaur tracks were discovered in the French village of Plagne, in the Jura Mountains. Since then, a series of excavations at the site has uncovered other tracks, sprawling over more than 150 meters. They form the longest sauropod trackway ever to be found. Having compiled and analyzed the collected data, which is published in Geobios, scientists from the Laboratoire de Géologie de Lyon (CNRS / ENS de Lyon / Claude Bernard Lyon 1 University), the Laboratoire Magmas et Volcans (CNRS / Université Clermont Auvergne / Université Jean Monnet / IRD), and the Pterosaur Beach Museum conclude these tracks were left 150 million years ago by a dinosaur at least 35 m long and weighing no less than 35 t.

Dinosaur tracks in Plagne, France (stock image). Credit: © nmnac01 / Fotolia

    Dinosaur tracks in Plagne, France (stock image).Credit: © nmnac01 / Fotolia

In 2009, when sauropod tracks were discovered in the French village of Plagne — near Lyon — the news went round the world. After two members of the Oyonnax Naturalists’ Society spotted them, scientists from the Paléoenvironnements et Paléobiosphère research unit (CNRS / Claude Bernard Lyon 1 University) confirmed these tracks were the longest in the world. Between 2010 and 2012, researchers from the Laboratoire de Géologie de Lyon supervised digs at the site, a meadow covering three hectares. Their work unearthed many more dinosaur footprints and trackways. It turns out the prints found in 2009 are part of a 110-step trackway that extends over 155 m — a world record for sauropods, which were the largest of the dinosaurs.

Dating of the limestone layers reveals that the trackway was formed 150 million years ago, during the Early Tithonian Age of the Jurassic Period. At that time, the Plagne site lay on a vast carbonate platform bathed in a warm, shallow sea. The presence of large dinosaurs indicates the region must have been studded with many islands that offered enough vegetation to sustain the animals. Land bridges emerged when the sea level lowered, connecting the islands and allowing the giant vertebrates to migrate from dry land in the Rhenish Massif.

Additional excavations conducted as late as 2015 enabled closer study of the tracks. Those left by the sauropod’s feet span 94 to 103 cm and the total length can reach up to 3 meters when including the mud ring displaced by each step. The footprints reveal five elliptical toe marks, while the handprints are characterized by five circular finger marks arranged in an arc. Biometric analyses suggest the dinosaur was at least 35 m long, weighted between 35 and 40 t, had an average stride of 2.80 m, and traveled at a speed of 4 km/h. It has been assigned to a new ichnospecies1: Brontopodus plagnensis. Other dinosaur trackways can be found at the Plagne site, including a series of 18 tracks extending over 38 m, left by a carnivore of the ichnogenus Megalosauripus. The researchers have since covered these tracks to protect them from the elements. But many more remain to be found and studied in Plagne.

1 The prefix ichno- indicates that a taxon (e.g., a genus or species) has been defined on the basis of tracks or other marks left behind, rather than anatomical remains like bones.

  1. Jean-Michel Mazin, Pierre Hantzpergue, Nicolas Olivier. The dinosaur tracksite of Plagne (early Tithonian, Late Jurassic; Jura Mountains, France): The longest known sauropod trackway. Geobios, 2017; 50 (4): 279 DOI: 10.1016/j.geobios.2017.06.004
      2. CNRS. “World’s longest sauropod dinosaur trackway brought to light.” ScienceDaily. ScienceDaily, 13 November 2017. <www.sciencedaily.com/releases/2017/11/171113195133.htm>.
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WFS News: Site of asteroid impact changed the history of life

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An asteroid, also known as the Chicxulub Impactor, hit Earth some 66 million years ago, causing a crater 180 km wide. The impact of the asteroid heated organic matter in rocks and ejected it into the atmosphere, forming soot in the stratosphere.

Soot is a strong, light-absorbing aerosol that caused global climate changes that triggered the mass extinction of dinosaurs, ammonites, and other animals, and led to the macroevolution of mammals and the appearance of humans.

Based on results of a new study, the researchers say that the probability of the mass-extinction occurring was only 13 percent. This is because the catastrophic chain of events could only have occurred if the asteroid had hit the hydrocarbon-rich areas occupying approximately 13 percent of Earth’s surface.

Mass extinction only occurred when the asteroid having 9-km diameter hit the orange areas. Credit: Kunio Kaiho

Mass extinction only occurred when the asteroid having 9-km diameter hit the orange areas.
                                                                      Credit: Kunio Kaiho

Led by Tohoku University Professor Kunio Kaiho, the researchers came by their hypothesis by calculating the amount of soot in the stratosphere and estimating climate changes caused by soot using a global climate model developed at the Meteorological Research Institute. The results are significant because they explain the pattern of extinction and survival.

During the study, Kaiho thought that the amount of soot and temperature anomaly might have been affected by the amount of sedimentary organic-matter. So, he analyzed the amount of sedimentary organic-matter in Earth to obtain readings of temperature anomaly caused by soot in the stratosphere.

Naga Oshima of the Meteorological Research Institute conducted the global climate model calculations to obtain temperature anomalies caused by various amounts of soot injected into the stratosphere.

Kaiho clarified the relationship between the findings and concluded that the significant cooling and mass-extinction event could have only have occurred if the asteroid had hit hydrocarbon-rich areas occupying approximately 13 percent of Earth’s surface.

If the asteroid had hit a low-medium hydrocarbon area on Earth (occupying approximately 87 percent of Earth’s surface), mass extinction could not have occurred and the Mesozoic biota could have persisted beyond the Cretaceous/Paleogene boundary.

The site of the asteroid impact, therefore, changed the history of life on Earth.

According to the study, soot from hydrocarbon-rich areas caused global cooling of 8-11°C and cooling on land of 13-17°C. It also caused a decrease in precipitation by approximately 70-85 percent on land and a decrease of approximately 5-7°C in seawater temperature at a 50-m water depth, leading to mass extinction of life forms including dinosaurs and ammonites.

At the time, these hydrocarbon-rich areas were marine coastal margins, where the productivity of marine algae was generally high and sedimentary rocks were thickly deposited. Therefore, these areas contained a high amount of organic matter, part of which became soot from the heat of the asteroid’s impact.

Thus, the researchers concluded that the Chicxulub impact occurred in a hydrocarbon-rich area and is a rare case of mass extinction being caused at such an impact site.

Kaiho and Oshima are doing further studies to clarify the frequency of all the cooling events by impacts. Kaiho’s team is analyzing climate change caused by large volcanic eruptions that may have contributed to other mass extinctions. It is hoped that the results will lead to further understanding of the processes behind those mass extinctions.

  1. Kunio Kaiho, Naga Oshima. Site of asteroid impact changed the history of life on Earth: the low probability of mass extinction. Scientific Reports, November 2017 DOI: 10.1038/s41598-017-141990-x 
      2. Tohoku University. “Site of asteroid impact changed the history of life.” ScienceDaily. ScienceDaily, 10 November 2017. <www.sciencedaily.com/releases/2017/11/171110113950.htm>
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WFS News:Fossil of beaver the size of a bear found in Manitoba

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Part of the skull of a prehistoric giant beaver — which rivalled the modern bear in size — has been found in a gravel pit in southeastern Manitoba.

The jaw bone, including a long front incisor and the back teeth in near-perfect condition, was discovered in a quarry south of Steinbach.

(Randy Mooi / Manitoba Museum photo) Giant beaver jaw (Castoroides) compared to a modern beaver (Castor canadensis). Part of the skull of a giant beaver has turned up in southeastern Manitoba.

Dr. Randy Mooi / Manitoba Museum
giant beaver jaw (Castoroides) compared to a modern beaver (Castor canadensis).Part of the skull of a giant beaver has turned up in southeastern Manitoba. The beaver, which was as large as our bears today, is estimated by Manitoba Museum paleontologist Graham Young to be from 50,000 years ago during a thawing period of the Ice Age. It’s the first such fossil found in Manitoba and only the fourth occurrence of a giant beaver fossil in Canada.

The giant beaver fossil is the first of its kind found in Manitoba — and only the fourth in Canada — even though it has long been believed to have existed in the province. There is a replica giant beaver skull on display at Oak Hammock Marsh.

The giant beaver species became extinct more than 10,000 years ago.

Graham Young, the curator of paleontology at the Manitoba Museum, said people often telephone the Winnipeg institution with what they think is an important find, but when a staff take a look, it usually turns out to not be the case.

“This fellow just walked in around lunch time and said, I’ve got these things, are you interested in seeing them? He thought maybe it was a pig’s jaw because the front tooth is like a tusk,” said Young.

Instead, it’s one of the best paleontological finds in Manitoba in recent years. The jaw bone has not yet been radiocarbon dated — it’s in a lengthy line behind numerous other fossils found in the province — but wood in the vicinity has been dated to 44,000 years ago.

“This is an amazing piece, it really is,” said Young. “With so many bones, you can’t tell what it is right away. With this giant beaver jaw, there was no question what it was immediately.”

Not only is the jaw intact, but a dentist would give its teeth a gold star: the front tooth is almost 12 centimetres long.

“There’s nothing more diagnostic than finding the jaw. The big front tooth is like a chisel on these giant beavers,” Young said.

The man who brought in the fossil also donated an ancient bison vertebrae and a long, curved length of bone believed to be a rib from either a mammoth or mastodon.

(It could be a mastodon because a tree radiocarbon dated in the area was black spruce, Young said, and mastodon used to feast on black spruce sprigs. A mastodon tooth has also been found in southern Manitoba, near Blumenort.)

The donor has requested anonymity, and not to reveal the exact location the beaver fossil was found.

“One thing to emphasize is there’s a heck of a lot of gravel out there and it’s rare to find anything at all. To find bone, it’s a real needle in a haystack,” said Young.

The period of the giant beaver was during the Ice Age, but the fossil’s time would have likely been during an interval when the ice sheet retreated to the north somewhat before advancing again south.

The tail of a giant beaver was skinny, not flat like the modern beaver, and grew to up to 2 1/2 metres long. It’s been debated whether the giants were lodge-builders or made their homes by burrowing into the ground. Its front teeth are strong and long but shaped differently than today’s rodent, so they didn’t eat bark, Young said.

It’s believed the giant beaver wasn’t as prevalent as its family members are now in Canada.

The donated fossil jaw is in such good shape, the animal likely died near where it was found, Young said. Fossils are sometimes transported long distances by various natural forces.

Previous giant beaver fossils in Canada have been found near Old Crow in the Yukon, in New Brunswick and in the Don Valley area of Toronto.

The fossil at the Manitoba Museum is now undergoing a long, slow drying process in controlled-climate conditions that will take months, in order to reduce the chances of cracking.

“The pieces we got have probably been sitting below the water table for probably over 40,000 years and are incredibly saturated,” Young said.

Young believes the giant beaver went extinct around 11,000 years ago, along with about 25 other large animals due to the arrival of people in North America and the animals being stressed by climate change.

He hopes to eventually put the jaw on display in an exhibit of fossils found in southeast Manitoba.

Source: Article by Bill Redekop, winnipeg free press

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WFS News: Finger and toe fossils belonged to tiny primates 45 million years ago

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At Northern Illinois University, Dan Gebo opens a cabinet and pulls out a drawer full of thin plastic cases filled with clear gelatin capsules. Inside each numbered capsule is a tiny fossil — some are so small they rival the diminutive size of a mustard seed.

It’s hard to imagine that anyone would be able to recognize these flecks as fossils, much less link them to an ancient world that was very different from our own, yet has quite a bit to do with us — or the evolution of us.

The nearly 500 finger and toe bones belonged to tiny early primates — some half the size of a mouse. During the mid-Eocene period, about 45 million years ago, they lived in tree canopies and fed on fruit and insects in a tropical rainforest in what is now China.

The fossilized phalanges are described in detail in a new study by Gebo and colleagues, published online this fall ahead of print in the Journal of Human Evolution.

The fossils provide further evidence that early anthropoids were minuscule creatures. Credit: Northern Illinois University

          The fossils provide further evidence that early anthropoids were minuscule creatures.
                                                        Credit: Northern Illinois University

Representing nine different taxonomic families of primates and as many as 25 species, the specimens include numerous fossils attributed to Eosimias, the very first anthropoid known to date, and three fossils attributed to a new and much more advanced anthropoid. The anthropoid lineage would later include monkeys, apes and humans.

“The fossils are extraordinarily small, but in terms of quantity this is the largest single assemblage of fossil primate finger and toe specimens ever recorded,” said Gebo, an NIU professor of anthropology and biology who specializes in the study of primate anatomy.

All of the finger and toe fossils imply tree-dwelling primates with grasping digits in both hands and feet. Many of the smaller fossils are between 1 and 2 millimeters in length, and the animals would have ranged in full body size from 10 to 1,000 grams (0.35 to 35.3 ounces).

“The new study provides further evidence that early anthropoids were minuscule creatures, the size of a mouse or smaller,” Gebo said. “It also adds to the evidence pointing toward Asia as the initial continent for primate evolution. While apes and fossil humans do come from Africa, their ancestors came from Asia.”

The newly described fossils were originally recovered from a commercial quarry near the village of Shanghuang in the southern Jiangsu Province of China, about 100 miles west of Shanghai. In recent decades, Shanghuang has become well-known among paleontologists.

“Shanghuang is truly an amazingly diverse fossil primate locality, unequaled across the Eocene,” Gebo said. “Because no existing primate communities show this type of body-size distribution, the Shanghuang primate fauna emphasizes that past ecosystems were often radically different from those we are familiar with today.”

Co-author Christopher Beard, a paleontologist at the University of Kansas in Lawrence who has been working on Shanghuang fossils for 25 years, said the limestone in the quarry is of Triassic age — from the very beginning of the Age of Dinosaurs some 220 million years ago. Owing to a subsequent phase of erosion, the limestone developed large fissures containing fossil-rich sediments dating to the middle Eocene, after dinosaurs went extinct.

In the early 1990s, more than 10 tons of fossil-bearing matrix were collected from the fissures and shipped to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and the Carnegie Museum of Natural History in Pittsburgh. There, the matrix was washed and screened, yielding fossil bones and teeth from ancient mammals, many of which remain to be identified.

“Because of commercial exploitation of the quarry site, the fossil-bearing fissure-fillings at Shanghuang are now exhausted,” Beard said. “So, the fossils that we currently have are all that will ever be found from this site.”

Gebo was initially recruited during the late 1990s to spearhead research on primate limb and ankle bones from Shanghuang. That led to two publications in 2000, when he and colleagues first announced the discovery of 45 million-year-old, thumb-length primates, the smallest ever recovered, from this same site. The work identifying body parts also helped cement the status of Eosimias, first identified by Beard on the basis of jaw fragments discovered at the site, as an extremely primitive anthropoid lying at the very beginning of our lineage’s evolutionary past.

In more recent years, Gebo found additional specimens, sifting through miscellaneous elements from Shanghuang both at the Carnegie Museum and the University of Kansas. He brought the delicate and minuscule finger and toe fossils to NIU for study using traditional and electron-scanning microscopes.

The fossils that endured the millennia may be small but still have a story to tell. “We can actually identify different types of primates from the shapes of their fingers and toes,” Gebo said.

Primates are mammals, characterized by having bigger brains, grasping hands and feet, nails instead of claws and eyes located in the front of the skull. Living prosimians, or living lower primates, include lemurs and tarsiers, and have broader fingertips. In contrast, most living anthropoids, also known as higher primates, have narrow fingertips.

Fossils from the unnamed advanced anthropoid are narrow, Gebo said.

“These are the earliest known examples of those narrow fingers and toes that are key to anthropoid evolution,” he added. “We can see evolution occurring at this site, from the broader finger or toe tips to more narrow.”

Unlike other prehistoric forests across the globe that have a mixture of large and small primates, Shanghuang’s fossil record is unique in being nearly absent of larger creatures.

The unusual size distribution is likely the result of a sampling bias, Gebo said. Researchers might be missing the larger primate fauna because of processes affecting fossil preservation, and for similar reasons scientists at other Eocene localities could be missing the small-sized fauna.

“Many of the fossil specimens from Shanghuang show evidence of partial digestion by predatory birds, which may have specialized on preying upon the small primates and other mammals that are so common at Shanghuang, thus explaining the apparent bias toward small fossil species there,” Beard added.

Some of the primate fossils found in Shanghuang are found in other countries. Eosimias fossils have been recovered in Myanmar, for example. But Shanghuang stands out because of the presence of more advanced anthropoids and the sheer diversity of primates.

“You don’t find all of these fossil primates in one place except at Shanghuang,” Gebo said.

  1. Daniel L. Gebo, Marian Dagosto, Xijun Ni, K. Christopher Beard. Phalangeal morphology of Shanghuang fossil primates. Journal of Human Evolution, 2017; 113: 38 DOI: 10.1016/j.jhevol.2017.08.001
  2. Northern Illinois University. “Finger and toe fossils belonged to tiny primates 45 million years ago.” ScienceDaily. ScienceDaily, 9 November 2017. <www.sciencedaily.com/releases/2017/11/171109131215.htm>

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WFS News: Mammals were nocturnal until dinosaur extinction…

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With enormous predators like Tyrannosaurus Rex skulking around in the daytime it is not surprising that the first mammals chose to live under the cover of darkness.

In fact, a new study, from University College London has found that our ancestors did not emerge from the shadows until after the dinosaurs became extinct, around 66 million years ago.

Before then, all mammals were nocturnal, sleeping in the daytime and hunting or foraging at night, new data suggests.

After dinosaurs became extinct 66 million years ago, mammals became diurnal CREDIT: STOCKTREK IMAGES, INC. / ALAMY

After dinosaurs became extinct 66 million years ago, mammals became diurnal                                                                        CREDIT: STOCKTREK IMAGES, INC. / ALAMY

Researchers used computer algorithms to analyse details from 2415 species of living mammals to reconstruct the activity patterns of their ancestors.

They found that following the comet strike which killed off the dinosaurs, mammals shifted to an intermediate stage of mixed day and night living, before primarily venturing into the daylight.

“We were very surprised to find such close correlation between the disappearance of dinosaurs and the beginning of daytime activity in mammals, but we found the same result unanimously using several alternative analyses,” said lead author, doctoral student student Roi Maor of UCL.

The team found that the ancestors of gorillas and gibbons were the first to give up their nocturnal activity, a discovery which fits in with the fact that their descendants – which include humans – are the only mammals that see well in daylight.

Their vision and colour perception is comparable to those of diurnal reptiles and birds – groups which never left the daytime.

“It’s very difficult to relate behaviour changes in mammals that lived so long ago to ecological conditions at the time, so we can’t say that the dinosaurs dying out caused mammals to start being active in the daytime,” added co-author Professor Kate Jones.

“However, we see a clear correlation in our findings.”

Ancestral reconstruction is the extrapolation back in time from measured characteristics of individuals, or species, to their common ancestors.

For example, if  a mammal had long fingers and its sibling also has long fingers  it is likely that a parent had long fingers.

The research was published in the journal Nature Ecology and Evolution.

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WFS News: komatiites may offer new insights into earth’s evolution

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The first 1.5 billion years of Earth’s evolution is subject to considerable uncertainty due to the lack of any significant rock record prior to four billion years ago and a very limited record until about three billion years ago. Rocks of this age are usually extensively altered making comparisons to modern rock quite difficult. In new research conducted at LSU, scientists have found evidence showing that komatiites, three-billion-year old volcanic rock found within the Earth’s mantle, had a different composition than modern ones. Their discovery may offer new information about the first one billion years of Earth’s development and early origins of life. Results of the team’s work has been published in the October 2017 edition of NATURE Geoscience.

The basic research came from more than three decades of LSU scientists studying and mapping the Barberton Mountains of South Africa. The research team, including LSU geology professors Gary Byerly and Huiming Bao, geology PhD graduate Keena Kareem, and LSU researcher Benjamin Byerly, conducted chemical analyses of hundreds of komatiite rocks sampled from about 10 lava flows.

“Early workers had mapped large areas incorrectly by assuming they were correlatives to the much more famous Komati Formation in the southern part of the mountains. We recognized this error and began a detailed study of the rocks to prove our mapping-based interpretations,” said Gary Byerly.

Photomicrographs of fresh olivine (large green, blue and pink crystals) and glass inclusion (lower left inset). Komatiite volcanic rocks from the 3.3 billion-year-old Weltevreden Formation are the freshest yet discovered in from Earth's early Archean. Trace elements, radiogenic and stable isotopes from these rocks and olivine separates provide key evidence for evolution of Earth's mantle. Credit: Keena Kareem, LSU

Photomicrographs of fresh olivine (large green, blue and pink crystals) and glass inclusion (lower left inset). Komatiite volcanic rocks from the 3.3 billion-year-old Weltevreden Formation are the freshest yet discovered in from Earth’s early Archean. Trace elements, radiogenic and stable isotopes from these rocks and olivine separates provide key evidence for evolution of Earth’s mantle.Credit: Keena Kareem, LSU

Within the rocks, they discovered original minerals called fresh olivine, which had been preserved in remarkable detail. Though the mineral is rarely found in rocks subjected to metamorphism and surface weathering, olivine is the major constituent of Earth’s upper mantle and controls the nature of volcanism and tectonism of the planet. Using compositions of these fresh minerals, the researchers had previously concluded that these were the hottest lavas to ever erupt on Earth’s surface with temperatures near 1600 degrees centigrade, which is roughly 400 degrees hotter than modern eruptions in Hawaii.

“Discovering fresh unaltered olivine in these ancient lavas was a remarkable find. The field work was wonderfully productive and we were eager to return to the lab to use the chemistry of these preserved olivine crystals to reveal clues of the Archean Mantle,” said Kareem

The researchers suggest that maybe a chunk of early-Earth magma ocean is preserved in the approximately 3.2 billion year-old minerals.

“The modern Earth shows little or no evidence of this early magma ocean because convection of the mantle has largely homogenized the layering produced in the magma ocean. Oxygen isotopes in these fresh olivines support the existence of ancient chunks of the frozen magma ocean. Rocks like this are very rare and scientifically valuable. An obvious next step was to do oxygen isotopes,” said Byerly.

This study grew out of work taking place in LSU’s laboratory for the study of oxygen isotopes, a world-class facility that attracts scientists from the U.S. and international institutions for collaborative work. The results of the study were so unusual that it required extra care to be certain of the results. Huiming Bao, who is also the head of LSU’s oxygen isotopes lab, said that the team triple and quadruple checked the data by running with different reference minerals and by calibrating with other independent labs.

“We attempted to reconcile the findings with some of the conventional explanations for lavas with oxygen isotope compositions like these, but nothing could fully explain all of the observations. It became apparent that these rocks preserve signatures of processes that occurred over four billion years ago and that are still not completely understood,” said Benjamin Byerly.

Oxygen isotopes are measured by the conversion of rock or minerals into a gas and measuring the ratios of oxygen with the different masses of 16, 17, and 18. A variety of processes fractionate oxygen on Earth and in the Solar System, including atmospheric, hydrospheric, biological, and high temperature and pressure.

“Different planets in our solar system have different oxygen isotope ratios. On Earth this is modified by surface atmosphere and hydrosphere, so variations could be due either to heterogeneous mantle (original accumulation of planetary debris or remnants of magma ocean) or surface processes,” said Byerly. “Either might be interesting to study. The latter because it would also provide information about the early surface temperature of Earth and early origins of life.”

This work was supported by a National Science Foundation grant awarded to Byerly, a NASA grant awarded to Bao, and general support from LSU.

  1. Benjamin L. Byerly, Keena Kareem, Huiming Bao, Gary R. Byerly. Early Earth mantle heterogeneity revealed by light oxygen isotopes of Archaean komatiites. Nature Geoscience, 2017; 10 (11): 871 DOI: 10.1038/ngeo3054

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WFS News: Chicxulub asteroid impact cooled Earth’s climate more than previously thought

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The Chicxulub asteroid impact that wiped out the dinosaurs likely released far more climate-altering sulfur gas into the atmosphere than originally thought, according to new research.

A new study makes a more refined estimate of how much sulfur and carbon dioxide gas were ejected into Earth’s atmosphere from vaporized rocks immediately after the Chicxulub event. The study’s authors estimate more than three times as much sulfur may have entered the air compared to what previous models assumed, implying the ensuing period of cool weather may have been colder than previously thought.

The new study lends support to the hypothesis that the impact played a significant role in the Cretaceous-Paleogene extinction event that eradicated nearly three-quarters of Earth’s plant and animal species, according to Joanna Morgan, a geophysicist at Imperial College London in the United Kingdom and co-author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union.

“Many climate models can’t currently capture all of the consequences of the Chicxulub impact due to uncertainty in how much gas was initially released,” Morgan said. “We wanted to revisit this significant event and refine our collision model to better capture its immediate effects on the atmosphere.”

The Chicxulub Crater was created by an asteroid that struck the Earth about 66 million years ago

The Chicxulub Crater was created by an asteroid that struck the Earth about 66 million years ago

The new findings could ultimately help scientists better understand how Earth’s climate radically changed in the aftermath of the asteroid collision, according to Georg Feulner, a climate scientist at the Potsdam Institute for Climate Impact Research in Potsdam, Germany who was not involved with the new research. The research could help give new insights into how Earth’s climate and ecosystem can significantly change due to impact events, he said.

“The key finding of the study is that they get a larger amount of sulfur and a smaller amount of carbon dioxide ejected than in other studies,” he said. “These improved estimates have big implications for the climactic consequences of the impact, which could have been even more dramatic than what previous studies have found.”

A titanic collision

The Chicxulub impact occurred 66 million years ago when an asteroid approximately 12 kilometers (7 miles) wide slammed into Earth. The collision took place near what is now the Yucatán peninsula in the Gulf of Mexico. The asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event, a mass extinction that erased up to 75 percent of all plant and animal species, including the dinosaurs.

The asteroid collision had global consequences because it threw massive amounts of dust, sulfur and carbon dioxide into the atmosphere. The dust and sulfur formed a cloud that reflected sunlight and dramatically reduced Earth’s temperature. Based on earlier estimates of the amount of sulfur and carbon dioxide released by the impact, a recent study published in Geophysical Research Letters showed Earth’s average surface air temperature may have dropped by as much as 26 degrees Celsius (47 degrees Fahrenheit) and that sub-freezing temperatures persisted for at least three years after the impact.

In the new research, the authors used a computer code that simulates the pressure of the shock waves created by the impact to estimate the amounts of gases released in different impact scenarios. They changed variables such as the angle of the impact and the composition of the vaporized rocks to reduce the uncertainty of their calculations.

The new results show the impact likely released approximately 325 gigatons of sulfur and 425 gigatons of carbon dioxide into the atmosphere, more than 10 times global human emissions of carbon dioxide in 2014. In contrast, the previous study in Geophysical Research Letters that modeled Earth’s climate after the collision had assumed 100 gigatons of sulfur and 1,400 gigatons of carbon dioxide were ejected as a result of the impact.

Improving the impact model

The new study’s methods stand out because they ensured only gases that were ejected upwards with a minimum velocity of 1 kilometer per second (2,200 miles per hour) were included in the calculations. Gases ejected at slower speeds didn’t reach a high enough altitude to stay in the atmosphere and influence the climate, according to Natalia Artemieva, a senior scientist at the Planetary Science Institute in Tucson, Arizona and co-author of the new study.

Older models of the impact didn’t have as much computing power and were forced to assume all the ejected gas entered the atmosphere, limiting their accuracy, Artemieva said.

The study authors also based their model on updated estimates of the impact’s angle. An older study assumed the asteroid hit the surface at an angle of 90 degrees, but newer research shows the asteroid hit at an angle of approximately 60 degrees. Using this revised angle of impact led to a larger amount of sulfur being ejected into the atmosphere, Morgan said.

The study’s authors did not model how much cooler Earth would have been as a result of their revised estimates of how much gas was ejected. Judging from the cooling seen in the previous study, which assumed a smaller amount of sulfur was released by the impact, the release of so much sulfur gas likely played a key role in the extinction event. The sulfur gas would have blocked out a significant amount of sunlight, likely leading to years of extremely cold weather potentially colder than the previous study found. The lack of sunlight and changes in ocean circulation would have devastated Earth’s plant life and marine biosphere, according to Feulner.

The release of carbon dioxide likely led to some long-term climate warming, but its influence was minor compared to the cooling effect of the sulfur cloud, Feulner said.

Along with gaining a better understand of the Chicxulub impact, researchers can also use the new study’s methods to estimate the amount of gas released during other large impacts in Earth’s history. For example, the authors calculated the Ries crater located in Bavaria, Germany was formed by an impact that ejected 1.3 gigatons of carbon dioxide into the atmosphere. This amount of gas likely had little effect on Earth’s climate, but the idea could be applied to help understand the climactic effects of larger impacts.

Natalia Artemieva, Joanna Morgan. Quantifying the Release of Climate-Active Gases by Large Meteorite Impacts With a Case Study of Chicxulub. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL074879 

American Geophysical Union. “Dinosaur-killing asteroid impact cooled Earth’s climate more than previously thought.” ScienceDaily. ScienceDaily, 31 October 2017. <www.sciencedaily.com/releases/2017/10/171031111446.htm>.

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WFS News: why the largest are not always the fastest

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No other animal on land is faster than a cheetah — the elephant is indeed larger, but slower. For small to medium-sized animals, larger also means faster, but for really large animals, when it comes to speed, everything goes downhill again. For the first time, it is now possible to describe how this parabola-like relationship between body size and speed comes about. A research team under the direction of the German Centre for Integrative Biodiversity Research (iDiv) and the Friedrich Schiller University Jena (Germany) have managed to do so thanks to a new mathematical model, and also published their findings in the journal Nature Ecology and Evolution.

A beetle is slower than a mouse, which is slower than a rabbit, which is slower than a cheetah… which is slower than an elephant? No! No other animal on land is faster than a cheetah — the elephant is indeed larger, but slower. For small to medium-sized animals, larger also means faster, but for really large animals, when it comes to speed, everything goes downhill again. For the first time, it is now possible to describe how this parabola-like relationship between body size and speed comes about.

There is a parabola-like relationship between the body mass of animals and the maximum speed they can reach. For the first time, researchers are able to describe how this comes about, thanks to a simple mathematical model. Credit: Copyright Myriam Hirt

There is a parabola-like relationship between the body mass of animals and the maximum speed they can reach. For the first time, researchers are able to describe how this comes about, thanks to a simple mathematical model.Credit: Copyright Myriam Hirt

The model is amazingly simple: The only information that it must be ‘fed’ with is the weight of a particular animal as well as the medium it moves in, so either land, air or water. On this basis alone, it calculates the maximum speed that an animal can reach with almost 90% accuracy. “The best feature of our model is that it is universally applicable,” says the lead author of the study, Myriam Hirt of the iDiv research centre and the University of Jena. “It can be performed for all body sizes of animals, from mites to blue whales, with all means of locomotion, from running and swimming to flying, and can be applied in all habitats.” Moreover, the model is by no means limited to animal species that currently exist, but can be applied equally well to extinct species.

Tyrannosaurus reached a speed of only 17 miles/hour

“To test whether we can use our model to calculate the maximum speed of animals that are already extinct, we have applied it to dinosaur species, whose speed has up to now been simulated using highly complex biomechanical processes,” explains Hirt. The result is that the simple model delivered results for Triceratops, Tyrannosaurus, Brachiosaurus and others that matched those from complex simulations — and were not exactly record-breaking for Tyrannosaurus, who reached a speed of only 27 km/h (17 mi/h). “This means that in future, our model will enable us to estimate, in a very simple way, how fast other extinct animals were able to run,” says the scientist.

Mass has to overcome inertia

Two assumptions are the basis of the model. The first assumption is related on the fact that animals reach their maximum speeds during comparatively short sprints, and not while running over long distances. Unlike running over longer distances, where the body constantly resupplies the muscles with energy (aerobic metabolism), sprinting uses energy that is stored in the muscles themselves but which is exhausted relatively quickly (anaerobic metabolism). It seems logical enough: the larger the animal, the more muscle it has — and thus the faster it can sprint. However, Newton’s laws of motion also apply in the animal kingdom, we know mass has to overcome inertia, and so a five-tonne African elephant simply cannot start moving as quickly as a 2.5-gramme Etruscan shrew. By the time large animals such as the elephant get up to full speed while sprinting, their rapidly available energy reserves also soon run out. Taken together, these two assumptions result in the previously mentioned curve: A beetle is slower than a mouse, which is slower than a rabbit, which is slower than a cheetah — which is faster than an elephant.

@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

  1. Myriam R. Hirt, Walter Jetz, Björn C. Rall, Ulrich Brose. A general scaling law reveals why the largest animals are not the fastest. Nature Ecology & Evolution, 2017; DOI: 10.1038/s41559-017-0241-4
  2. Friedrich Schiller University Jena. “Why Tyrannosaurus was a slow runner and why the largest are not always the fastest.” ScienceDaily. ScienceDaily, 17 July 2017.

WFS News: mysterious ancient cone-shaped sea creatures(Hyoliths ) are Palaeozoic lophophorates

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One branch on the tree of life is a bit more crowded today. A team of scientists led by 20-year-old University of Toronto (U of T) undergraduate student Joseph Moysiuk has finally determined what a bizarre group of extinct cone-shaped animals actually are.

Known as hyoliths, these marine creatures evolved over 530 million years ago during the Cambrian period and are among the first animals known to have produced mineralized external skeletons.

Long believed to belong to the same family as snails, squid and other molluscs, a study published today in the scientific journal Nature shows that hyoliths are instead more closely related to brachiopods — a group of animals which has a rich fossil record, although few living species remain today.

Brachiopods have a soft body enclosed between upper and lower shells (valves), unlike the left and right arrangement of valves in bivalve molluscs. Brachiopods open their valves at the front when feeding, but otherwise keep them closed to protect their feeding apparatus and other body parts.

Although the skeletal remains of hyoliths are abundant in the fossil record, key diagnostic aspects of their soft-anatomy remained critically absent until now.

“Our most important and surprising discovery is the hyolith feeding structure, which is a row of flexible tentacles extending away from the mouth, contained within the cavity between the lower conical shell and upper cap-like shell,” said Moysiuk. “Only one group of living animals — the brachiopods — has a comparable feeding structure enclosed by a pair of valves. This finding demonstrates that brachiopods, and not molluscs, are the closest surviving relatives of hyoliths.

“It suggests that these hyoliths fed on organic material suspended in water as living brachiopods do today, sweeping food into their mouths with their tentacles,” Moysiuk said.

Moysiuk, who studies Earth sciences and ecology & evolutionary biology, completed this project as part of the Research Opportunity Program at U of T, a special undergraduate research program in the Faculty of Arts & Science.

The distinctive appearance and structure of the hyolith skeleton has obstructed previous attempts to classify these animals. All hyoliths had an elongated, bilaterally symmetrical cone-shaped shell and a smaller cap-like shell which covered the opening of the conical shell (known as an operculum). Some species also bore a pair of rigid, curved spines (known as helens) that protruded from between the conical shell and operculum — structures with no equivalents in any other group of animals.

Examination of the orientation of the helens in multiple hyolith specimens from the Burgess Shale suggests that these spines may have been used like stilts to lift the body of the animal above the sediment, elevating the feeding apparatus to enhance feeding.

Moysiuk and coauthors Martin Smith at Durham University in the United Kingdom, and Jean-Bernard Caron at the Royal Ontario Museum (ROM) and U of T were able to complete the descriptions based mainly on newly discovered fossils from the renowned Cambrian Burgess Shale in British Columbia.

“Burgess Shale fossils are exceptional because they show preservation of soft tissues which are not usually preserved in normal conditions,” said Caron, Moysiuk’s research supervisor, who is the senior curator of invertebrate palaeontology at the ROM and an associate professor in U of T’s Departments of Earth Sciences and Ecology & Evolutionary Biology.

“Although a molluscan affinity was proposed by some authors, this hypothesis remained based on insufficient evidence. Hyoliths became an orphaned branch on the tree of life, an embarrassment to paleontologists. Our most recent field discoveries were key in finally cracking their story, around 175 years after the first description of a hyolith.”

Dorsal view of specimens, anterior to the top. Detail and whole specimen. ROM59943.1, H. carinatus from Stanley Glacier (Kootenay National Park, B.C.), showing partially extended lophophore, with tentacles beyond the operculum margin. Credit: © Royal Ontario Museum

Dorsal view of specimens, anterior to the top. Detail and whole specimen. ROM59943.1, H. carinatus from Stanley Glacier (Kootenay National Park, B.C.), showing partially extended lophophore, with tentacles beyond the operculum margin.
Credit: © Royal Ontario Museum

Caron led recent fieldwork activities to the Burgess Shale which resulted in the discovery of many specimens that form the basis of this study. The key specimens came from recently discovered deposits near Stanley Glacier and Marble Canyon in Kootenay National Park, about 40 kilometres southeast of the original Burgess Shale site in Yoho National Park.

The Burgess Shale is one of the most important fossil deposits for studying the origin and early evolution of animals that took place during the Cambrian period, starting about 542 million years ago. Hyoliths are just one of the profusion of animal groups that characterize the fauna of the ‘Cambrian Explosion’. They became a diverse component of marine ecosystems around the globe for more than 280 million years, only to go extinct 252 million years ago, prior to the evolution of the first dinosaurs.

“Resolving the debate over the hyoliths adds to our understanding of the Cambrian Explosion, the period of rapid evolutionary development when most major animal groups emerge in the fossil record,” said Smith, who started this research at the University of Cambridge and who is now a lecturer in paleontology at Durham University. “Our study reiterates the importance of soft tissue preservation from Burgess Shale-type deposits in illuminating the evolutionary history of creatures about which we still know very little.”

The Burgess Shale, from which the specimens were recovered from several locations, is part of the Canadian Rocky Mountain Parks World Heritage Site. It is one of the most important fossil deposits for understanding the origin and early evolution of animals that took place during the Cambrian Explosion starting about 542 million years ago.

Parks Canada protects this globally significant site, and supports peer-reviewed scientific research that continues to enhance our understanding of these rich paleontological deposits. This discovery adds another element to the dramatic story of early animal evolution that Parks Canada guides share enthusiastically with hundreds of park visitors every year.

Funding for the research was provided primarily by the Royal Ontario Museum and a Natural Sciences and Engineering Research Council of Canada Discovery Grant to Caron.

Joseph Moysiuk, Martin R. Smith, Jean-Bernard Caron. Hyoliths are Palaeozoic lophophorates. Nature, 2017; DOI: 10.1038/nature20804

WFS News: Did dark matter kill the dinosaurs?

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More than 99% of all the species that have ever lived on our planet are now extinct, and while the majority of these die-offs can be attributed to competition or failure to adapt, many perished during dramatic cataclysmic events. The fossil record shows us that these mass extinctions seem to occur periodically in cycles of approximately 26 to 30 million years—which, interestingly, is similar to the amount of time it takes our sun to bob up and down through the galactic disc and cross the center line of the Milky Way.

This region, known as the galactic plane, is crowded with clouds of dust and gas which could disturb space debris within our solar system and send some hurtling towards our planet, which would fit in with some of the mass extinctions. However, according to new research, there could be something else at play: dark matter.

As described in Monthly Notices of the Royal Astronomical Society, passing through concentrated regions of this elusive, invisible stuff could also send comets on an Earth-bound collision course. Furthermore, dark matter particles could also ramp up temperatures in our planet’s core, which could affect geological systems and trigger extinction events.

Mass Extinctions On Earth

 Mass Extinctions On Earth

Our galaxy, the Milky Way, is a huge flat disk of stars, dust and gas measuring some 120,000 light-years across. The center line of this huge spinning disk, or galactic plane, is known to be concentrated with dust and gas, but also seems to be crowded with dark matter. Although we can’t directly observe this substance, scientists know it exists because it exerts gravitational effects on other objects in space. From these observations, scientists have estimated that each square light-year of the galactic plane contains around one solar mass of dark matter.

While our solar system rotates around the Milky Way, which takes around 250 million years, it also vertically oscillates through the galactic disk, passing through the galactic plane around every 30 million years or so. This correlates with the documented intervals between mass extinction events and comet impacts on Earth, which prompted scientist Michael Rampino from New York University to consider further what could be going on.

Although previous work has suggested that the concentration of dust and gas in the plane could be responsible for messing up the orbits of comets in our solar system, Rampino proposes that dark matter could also be a contributing factor. Clouds of the stuff could disturb the orbits of space debris and fling some towards Earth, causing huge collision events like the famous comet strike 66 million years ago which wiped out the dinosaurs.

Another possibility is that, as our planet passes through the plane, dark matter particles could get caught in our planet’s gravity, eventually causing them to fall towards Earth’s core and accumulate here. These particles would then begin to annihilate each other over time, creating an immense amount of heat in the core, rising its temperature by several hundred degrees Celsius. Over millions of years, this heat could travel towards the surface, triggering events such as volcanic eruptions or changes in global climate and sea level, which could wipe out a large number of species on Earth.

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