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Early Earth less hellish than previously thought

Early Earth less hellish than previously thought | Amazing Science | Scoop.it

Conditions on Earth for the first 500 million years after it formed may have been surprisingly similar to the present day, complete with oceans, continents and active crustal plates.


This alternate view of Earth’s first geologic eon, called the Hadean, has gained substantial new support from the first detailed comparison of zircon crystals that formed more than 4 billion years ago with those formed contemporaneously in Iceland, which has been proposed as a possible geological analog for early Earth.


The study was conducted by a team of geologists directed by Calvin Miller, the William R. Kenan Jr. Professor of Earth and Environmental Sciences at Vanderbilt University, and published online this weekend by the journal Earth and Planetary Science Letters in a paper titled, “Iceland is not a magmatic analog for the Hadean: Evidence from the zircon record.”


From the early 20th century up through the 1980’s, geologists generally agreed that conditions during the Hadean period were utterly hostile to life. Inability to find rock formations from the period led them to conclude that early Earth was hellishly hot, either entirely molten or subject to such intense asteroid bombardment that any rocks that formed were rapidly remelted. As a result, they pictured the surface of the Earth as covered by a giant “magma ocean.”


Two schools of thought have emerged: One argues that Hadean Earth was surprisingly similar to the present day. The other maintains that, although it was less hostile than formerly believed, early Earth was nonetheless a foreign-seeming and formidable place, similar to the hottest, most extreme, geologic environments of today. A popular analog is Iceland, where substantial amounts of crust are forming from basaltic magma that is much hotter than the magmas that built most of Earth’s current continental crust.


“We reasoned that the only concrete evidence for what the Hadean was like came from the only known survivors: zircon crystals – and yet no one had investigated Icelandic zircon to compare their telltale compositions to those that are more than 4 billion years old, or with zircon from other modern environments,” said Miller.

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Paleontologists just found the dinosaur Dreadnoughtus, an 85-foot-long titan - the most massive ever discovered

Paleontologists just found the dinosaur Dreadnoughtus, an 85-foot-long titan - the most massive ever discovered | Amazing Science | Scoop.it

Today an international team of paleontologists unveiled the newest Mesozoic giantDreadnoughtus schrani. Weighing in at an astonishing 65 tons, standing two stories high at the shoulder, and measuring 85 feet long, this titan is the heaviest dinosaur we've ever (accurately) measured. And its discovery represents the most fossil mass ever found for a single organism—a paleontologist's dream. 

"For the largest dinosaurs, which we call titanosaurs, finding anything around 20 percent of the fossil is usually considered a home run," says Kenneth Lacovara, the lead Drexel University paleontologist behind the find. "Normally you only find a handful of bones, and the previous record was a 27 percent complete skeleton. With Dreadnoughtus we found 70 percent." 

Near-Complete: The reason near-complete finds are so rare is because fossilization requires a quick burial in sediment. As you can imagine, it's an extraordinary occurrence for something as big as a Dreadnoughtus to be buried so quickly. But according to Lacovara, the scientists believe a rapid pair of floods, caused by broken earthen levees in the valley where Dread was found, are behind the impressively complete find. Sedimentary records in nearby areas back up this idea.

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The dead walk again: An arachnid that lived 410 million years ago has crawled back into the virtual world

The dead walk again: An arachnid that lived 410 million years ago has crawled back into the virtual world | Amazing Science | Scoop.it

A spider-like creature's remains were so well preserved in fossil form that scientists could see all its leg joints, allowing them to recreate its likely gait using computer graphics.


Known as a trigonotarbid, the animal was one of the first predators on land. Its prey were probably early flightless insects and other invertebrates, which it would run down and jump on.


"We know quite a bit about how it lived," said Russell Garwood, a palaeontologist with the University of Manchester, UK. "We can see from its mouth parts that it pre-orally digested its prey - something that most arachnids do - because it has a special filtering plate in its mouth. So, that makes us fairly sure it vomited digestive enzymes on to its prey and then sucked up liquid food," he explained.


The trigonotarbid specimens studied by Dr Garwood and colleagues are just a few millimetres in length. They were unearthed in Scotland, near the Aberdeenshire town of Rhynie. Its translucent Early Devonian chert sediments are renowned for their exquisite fossils.


The team used a collection held at the Natural History Museum in London that have actually been prepared since the 1920s. The rock had been cut into extremely fine slices just a few tens of microns thick, making it possible to construct 3D models of the arachnids, much like a doctor might do with the X-ray slices obtained in a CAT scan.


"We could see the articulation points in the legs," explained Dr Garwood. "Between each part of the leg, there are darker pieces where they join, and that allowed us to work out the range of movement.


"We then compared that with the gaits of modern spiders, which are probably a good analogy because they have similar leg proportions. The software enabled us to see the centre of mass and find a gait that worked. If it's too far back compared to the legs, the posterior drags on the ground. The trigonotarbid is an alternating tetrapod, meaning there are four feet on the ground at any one time."


"This new study has gone further and shows us how they probably walked. For me, what's really exciting here is that scientists themselves can make these animations now, without needing the technical wizardry (and immense costs) of a Jurassic-Park style film. When I started working on fossil arachnids, we were happy if we could manage a sketch of what they used to look like. Now, they run across our computer screens."


The work is part of a special collection of papers on 3D visualisations of fossils published in the Journal of Paleontology.


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New to Google Earth: Ancient Flying Reptiles Database and Mapping Tool

New to Google Earth: Ancient Flying Reptiles Database and Mapping Tool | Amazing Science | Scoop.it

A newly developed website catalogs more than 1,300 specimens of extinct flying reptiles called pterosaurs, thus enabling users to map out the ancient creatures on Google Earth. The goal is to help researchers find trends in the evolution and diversity of theseancient winged reptiles.


"Having a very specific database like this, which is just for looking at individual fossil specimens of pterosaurs, is very helpful, because you can ask questions that you couldn't have answered with bigger databases [of more animals]," said Matthew McLain, a doctoral candidate in paleontology at Loma Linda University in California and one of the three developers of the site. McLain and his colleagues call their database PteroTerra


Pterosaurs were the first flying vertebrates. They lived between 228 million and 66 million years ago, and went extinct around the end of the Cretaceous period. During that time, this group evolved to be incredibly diverse. Some were tiny, like the sparrow-size Nemicolopterus crypticus, which lived 120 million years ago in what is now China. Others were simply huge, like Quetzalcoatlus, which was as tall as a giraffe and probably went around spearing little dinosaurs with its beak like a stork might snack on frogs.

Paleontological databases are common tools, because they allow researchers to navigate through descriptions of fossil specimens. One of the largest, the Paleobiology Database, has more than 50,000 individual entries.


McLain and his colleagues wanted something more targeted. They painstakingly built PteroTerra from the ground up. McLain, as the paleontologist on the project, read published papers on pterosaurs and visited museums to catalog specimens.


"I think we have every species represented, so in that sense, it's pretty complete," he told Live Science. The database does not contain every specimen of pterosaur material ever found — tens of thousands of fossil fragments have been discovered — but McLain hopes to get other paleontologists on board as administrators to upload their specimen data.

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Amber discovery indicates Lyme disease is older than human race

Amber discovery indicates Lyme disease is older than human race | Amazing Science | Scoop.it
Lyme disease is a stealthy, often misdiagnosed disease that was only recognized about 40 years ago, but new discoveries of ticks fossilized in amber show that the bacteria which cause it may have been lurking around for 15 million years -- long before any humans walked on Earth. The findings were made by researchers who studied 15-20 million-year-old amber from the Dominican Republic that offer the oldest fossil evidence ever found of Borrelia, a type of spirochete-like bacteria that to this day causes Lyme disease.


"Ticks and the bacteria they carry are very opportunistic," said George Poinar, Jr., a professor emeritus in the Department of Integrative Biology of the OSU College of Science, and one of the world's leading experts on plant and animal life forms found preserved in amber. "They are very efficient at maintaining populations of microbes in their tissues, and can infect mammals, birds, reptiles and other animals.


"In the United States, Europe and Asia, ticks are a more important insect vector of disease than mosquitos," Poinar said. "They can carry bacteria that cause a wide range of diseases, affect many different animal species, and often are not even understood or recognized by doctors. "It's likely that many ailments in human history for which doctors had no explanation have been caused by tick-borne disease."


Lyme disease is a perfect example. It can cause problems with joints, the heart and central nervous system, but researchers didn't even know it existed until 1975. If recognized early and treated with antibiotics, it can be cured. But it's often mistaken for other health conditions. And surging deer populations in many areas are causing a rapid increase in Lyme disease -- the confirmed and probable cases of Lyme disease in Nova Scotia nearly tripled in 2013 over the previous year.


The new research shows these problems with tick-borne disease have been around for millions of years.


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Longer than a Blue Whale: 'Biggest Dinosaur ever' Discovered

Longer than a Blue Whale: 'Biggest Dinosaur ever' Discovered | Amazing Science | Scoop.it

Fossilized bones of a dinosaur believed to be the largest creature ever to walk the Earth have been unearthed in Argentina, paleontologists say. Based on its huge thigh bones, it was 40m (130ft) long and 20m (65ft) tall. Weighing in at 77 tonnes, it was as heavy as 14 African elephants, and seven tonnes heavier than the previous record holder, ArgentinosaurusScientists believe it is a new species of titanosaur - an enormous herbivore dating from the Late Cretaceous period. A local farm worker first stumbled on the remains in the desert near La Flecha, about 250km (135 miles) west of Trelew, Patagonia. The fossils were then excavated by a team of paleontologists from the Museum of Palaeontology Egidio Feruglio, led by Dr Jose Luis Carballido and Dr Diego Pol. They unearthed the partial skeletons of seven individuals - about 150 bones in total - all in "remarkable condition".

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How Birds Survived the Dinosaur Apocalypse

How Birds Survived the Dinosaur Apocalypse | Amazing Science | Scoop.it

Study suggests that, by getting smaller, birds made it through one of the worst extinction events to rock the planet.


When nearly every dinosaur went extinct 66 million years ago, the only ones that survived were those that had shrunk—that is, the birds. Today, there are 10,000 species of these feathered fliers, making them the most diverse of all the four-limbed animals. A new study reveals why this lineage has been so successful: Birds started downsizing well before the rest of the dinosaurs disappeared.


“This is a very impressive piece of work and by far the most comprehensive analysis of dinosaur body size that has been conducted,” says Stephen Brusatte, a paleontologist at the University of Edinburgh in the United Kingdom, who was not involved in the research. “The study shows that birds didn’t just become small suddenly, but were the end product of a long-term trend of body size decline that took many tens of millions of years.”


Dinosaurs were small in the beginning. About 230 million years ago, most weighed between 10 and 35 kilograms and were as big as a medium-sized dog. But many species soon soared to tractor-trailer proportions, reaching 10,000 kilograms within 30 million years. Later on, dinosaurs like the mightyArgentinosaurus, which stretched some 35 meters from nose to tail, weighed in at a staggering 90,000 kilograms.


Although many dinosaurs were getting bigger and bulkier over millions of years, one group seems to have hedged its bets on body size: the maniraptorans, feathered dinos that include Velociraptor of Jurassic Park fame and that eventually gave rise to the birds. To pin down how dinosaur size changed over time, a team led by Roger Benson, a paleontologist at the University of Oxford in the United Kingdom, estimated the body size of 426 different species, using the thickness of their fossilized hind leg bones as a proxy for their overall weight.


The team found that although all dinosaur groups rapidly changed size at the beginning of dinosaur evolution—primarily by getting bigger—that trend slowed down fairly quickly in almost all groups. For the most part, the dinos that got big stayed that way. The exception was the maniraptorans, which continued to evolve bigger and smaller species as they expanded into an ever wider variety of ecological niches over a period of 170 million years.

When an asteroid hit Earth 66 million years ago, only those feathered maniraptorans that had downsized to about 1 kilogram or so—the birds—were able to survive, probably because their small size allowed them to adapt more easily to changing conditions, the team concludes online today inPLOS Biology. The researchers argue that being small made it easier for maniraptorans to adapt to a wider variety of habitats, whereas the rest of the dinosaurs, encumbered by their huge bodies and enormous food requirements, simply didn’t make it.

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Asteroid and Meteorite Impacts Can Preserve Biodata for Millions of Years

Asteroid and Meteorite Impacts Can Preserve Biodata for Millions of Years | Amazing Science | Scoop.it

In two separate studies, geologists led by Dr. Haley Sapers from the University of Western Ontario and Dr. Pete Schultz of Brown University have found floral, microbial and organic matter in glass created by ancient asteroid, comet and meteorite impacts. Such glass samples could provide a snapshot of environmental conditions at the time of those impacts and could be a good place to look for signs of ancient life on Mars.


In the first study, published in the journal Geology, Dr Schultz with colleagues found fragments of leaves and preserved organic compounds lodged inside glass created by a several ancient impacts in Argentina. “The soil of eastern Argentina, south of Buenos Aires, is rife with impact glass created by at least seven different impacts that occurred between 6,000 and 9 million years ago,” Dr Schultz explained. “One of those impacts, dated to around 3 million years ago, coincides with the disappearance of 35 animal genera.”

“We know these were major impacts because of how far the glass is distributed and how big the chunks are. These glasses are present in different layers of sediment throughout an area about the size of Texas,” he said.


Within glass associated with two of those impacts – one from 3 million years ago and one from 9 million years ago – the team found exquisitely preserved plant matter.


In the second study, published also in the journal Geology, Dr Sapers and her colleagues discovered microbes preserved in impact glass. They analyzed tubular features in hydrothermally altered impact glass from the Ries Impact Structure, Germany, that are remarkably similar to the bioalteration textures observed in volcanic glasses.


Mineral-forming processes cannot easily explain the distribution and shapes of the Ries tubular features; therefore, they suggest the tubules formed by microbes etching their way through the impact glass as they excreted organic acids.


A meteorite impact into a water-rich target such as Earth or Mars has the potential to generate a post-impact hydrothermal system.

Impact structures, especially post-impact hydrothermal systems, represent an understudied habitat with potential relevance to early life and the evolution of early life on Earth.


Understanding the biological significance of impact products such as impact glass on Earth will better inform the search for evidence of life and past life on other terrestrial planets such as Mars.

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Ancient shrimp-like animals had 'modern' hearts and blood vessels

Ancient shrimp-like animals had 'modern' hearts and blood vessels | Amazing Science | Scoop.it
In 520 million-year-old fossil deposits resembling an 'invertebrate version of Pompeii,' researchers have found an ancestor of modern crustaceans revealing the first-known cardiovascular system in exquisitely preserved detail. The organ system is surprisingly complex and adds to the notion that sophisticated body plans had already evolved more than half a billion years ago.


"This is the first preserved vascular system that we know of," said Nicholas Strausfeld, a Regents' Professor of Neuroscience at the University of Arizona's Department of Neuroscience, who helped analyze the find. Being one of the world's foremost experts in arthropod morphology and neuroanatomy, Strausfeld is no stranger to finding meaningful and unexpected answers to long-standing mysteries in the remains of creatures that went extinct so long ago scientists still argue over where to place them in the evolutionary tree.


The 3-inch-long fossil was entombed in fine dustlike particles – now preserved as fine-grain mudstone - during the Cambrian Period 520 million years ago in what today is the Yunnan province in China. Found by co-author Peiyun Cong near Kunming, it belongs to the species Fuxianhuia protensa, an extinct lineage of arthropods combining advanced internal anatomy with a primitive body plan.


"Fuxianhuia is relatively abundant, but only extremely few specimens provide evidence of even a small part of an organ system, not even to speak of an entire organ system," said Strausfeld, who directs the UA Center for Insect Science. "The animal looks simple, but its internal organization is quite elaborate. For example, the brain received many arteries, a pattern that appears very much like a modern crustacean."

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Recreation of Species: How far back can we go?

Recreation of Species: How far back can we go? | Amazing Science | Scoop.it

The lesson of the Jurassic Park tragedy was clear — man and dinosaur were not meant to coexist. It’s lucky then that dinosaur fossils are far too old to contain any genetic material that could be used for cloning. DNA breaks down over time, even when kept in ideal conditions, and a study of extinct moa bones has revealed an estimate of the half-life for our genes.


It might be odd to think of DNA having a half-life, as it’s usually associated with radioactive material — but as it measures the time taken for half of something to decay, it makes sense to talk about old samples of DNA in the same way. For example, uranium-235, the fissile material that can be used in nuclear power plants (and nuclear weapons), has a half-life of 703.8 million years. DNA, by comparison, doesn’t fare so well — according to a study of 158 samples of moa bones between 500 and 6,000 years old, DNA appears to have a half-life of around 521 years.


A study in the Proceedings of the Royal Society B saw palaeogeneticists from the universities of Perth and Copenhagen drilling into the bones of 158 different moa, the largest of the flightless birds which used to dominated New Zealand’s odd and unique ecosystem before the arrival of humans. The bones had all been collected from within a five kilometre radius, and they were estimated to have been buried at an average temperature of 13 degrees Celsius since the birds died. Their similar preservation conditions were key to ensuring that a reliable figure for the DNA decomposition could be found.


Averaging out the results from the different bones gave the average half-life of 521 years. That result is caveated, of course, as there are many factors that can also affect the rate of decay — soil acidity, bone health, extreme temperature, humidity, and so on. However, it does provide a baseline against which to assess the viability of obtaining DNA samples from future finds.


If there is a lot of DNA, preserved in absolutely ideal conditions, then it might hang around for several thousand years. Samples of Neanderthal DNA have been found in ancient teeth as old as 100,000 years old, and New Scientist reports that there have also been tiny fragments of DNA from insects and plants hundreds of thousands of years old found in ice cores, but these are too decayed to be used for cloning.


The moa could theoretically be cloned, if a good enough DNA sample is found. The moa is generally thought to have been hunted to extinction by the Maori residents of New Zealand before the arrival of European settlers in the 1700s, which isn’t too long enough by DNA standards. Or, a better candidate might be the woolly mammoth — intact specimens have been found frozen into the permafrost (including very recently by a boy out walking his dog), and it is thought that it will eventually be possible to implant a mammoth embryo into an elephant’s uterus, which will grow into a full-on baby mammoth. We may even be able to reintroduce them into the wild, which is really the least we could do after driving them to extinction in the first place.

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Picture proves that Man hunted the woolly mammoth

Picture proves that Man hunted the woolly mammoth | Amazing Science | Scoop.it
This is the clearest evidence that our ancestors speared and killed the extinct giant.


These unique photographs seen by the world for the first time show the wounded vertebrae of the woolly mammoth found in Siberia. Forensic evidence proves the hole was made by a spear or javelin, meaning the huge creature was slain by ancient man some 13,470 years ago. It does not answer the conundrum that still puzzles scientists: why did the mammoths vanish from the face of the planet? Man's butchery may have been a factor, but can it really be the only one? Our exclusive pictures from Khanty-Mansiysk show the remains of a mammoth located a dozen years ago close to the confluence of the rivers Ob and Irtysh in the west of Siberia. 


The images show the thoracic vertebrae of a mammoth, which in all probability was marooned in a clay swamp when the hunters went in for the kill.  It is believed the weapon was thrown with great force at the creature. The vertebrae is pierced by a cone-shaped hole resulting from the penetration of a notched point, and there are fragments of quartzite flakes lodged inside, according to Russian scientists.


The discovery was made at the Lugovskoe 'mammoth graveyard' by scientists Alexander Pavlov and Eugeny Mashchenko in a swampy area where thousands of bones of mammals - mainly mammoths - have been unearthed by scientists since the 1990s. It remains unclear to what extent our ancestors ate the woolly mammoth when other, perhaps more succulent, food sources were available. Yet a related discovery last year in Lugovskoe was the remains of a 13,270 year old fireplace belonging to early men in this region.


The current theory is that mammoth bone was burned with charcoal, the fat from the bone giving a superior heat. Anton Rezvy, 39, head of the palaeontological department of the Khanty-Mansiysk Museum of Nature and Man, explained: 'The vertebra was found in Lugovskoe mammoth cemetery.'

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PIRatE Lab's curator insight, March 8, 11:01 AM

Nothing particularly new here, but this is yet another datapoint that we humans have ben altering populations for most of our species history.

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Theory on origin of animals challenged: Animals need only extremely little oxygen

Theory on origin of animals challenged: Animals need only extremely little oxygen | Amazing Science | Scoop.it
One of science's strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish Fjord shows that complex life does not need high levels of oxygen in order to live and grow.


The origin of complex life is one of science's greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 – 635 million years ago.


However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.


The living animals that most closely resemble the first animals on Earth are sea sponges. The species Halichondria panicea lives only a few meters from the University of Southern Denmark’s Marine Biological Research Centre in Kerteminde, and it was here that Daniel Mills fished out individuals for his research.


"When we placed the sponges in our lab, they continued to breathe and grow even when the oxygen levels reached 0.5 per cent of present day atmospheric levels", says Daniel Mills.

This is lower than the oxygen levels we thought were necessary for animal life.


The big question now is: If low oxygen levels did not prevent animals from evolving – then what did? Why did life consist of only primitive single-celled bacteria and amoebae for billions of years before everything suddenly exploded and complex life arose?


"There must have been other ecological and evolutionary mechanisms at play. Maybe life remained microbial for so long because it took a while to develop the biological machinery required to construct an animal. Perhaps the ancient Earth lacked animals because complex, many-celled bodies are simply hard to evolve", says Daniel Mills.

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Permian extinction happened within 60,000 years—much faster than previously thought

Permian extinction happened within 60,000 years—much faster than previously thought | Amazing Science | Scoop.it

The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land—including the largest insects known to have inhabited the Earth. Multiple theories have aimed to explain the cause of what's now known as the end-Permian extinction, including an asteroid impact, massive volcanic eruptions, or a cataclysmic cascade of environmental events. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted.


Now researchers at MIT have determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years—practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought.


"We've got the extinction nailed in absolute time and duration," says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation."


In addition to establishing the extinction's duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life.


But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period's volcanic eruptions that are estimated to have covered over five million cubic kilometers.


The new timeline adds weight to the theory that the extinction was triggered by massive volcanic eruptions from the Siberian Traps that released volatile chemicals, including carbon dioxide, into the atmosphere and oceans. With such a short extinction timeline, Bowring says it is possible that a single, catastrophic pulse of magmatic activity triggered an almost instantaneous collapse of all global ecosystems.


To confirm whether the Siberian Traps are indeed the extinction's smoking gun, Burgess and Bowring plan to determine an equally precise timeline for the Siberian Traps eruptions, and will compare it to the new extinction timeline to see where the two events overlap. The researchers will investigate additional areas in China to see if the duration of the extinction can be even more precisely determined.

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Microscopic Diamonds Suggest Cosmic Impact Responsible for Younger Dryas Climate Change 12,800 Years Ago

Microscopic Diamonds Suggest Cosmic Impact Responsible for Younger Dryas Climate Change 12,800 Years Ago | Amazing Science | Scoop.it

A new study published in The Journal of Geology provides support for the theory that a cosmic impact event over North America some 13,000 years ago caused a major period of climate change known as the Younger Dryas stadial, or “Big Freeze.”

 

Around 12,800 years ago, a sudden, catastrophic event plunged much of the Earth into a period of cold climatic conditions and drought. This drastic climate change—the Younger Dryas—coincided with the extinction of Pleistocene megafauna, such as the saber-tooth cats and the mastodon, and resulted in major declines in prehistoric human populations, including the termination of the Clovis culture.

 

With limited evidence, several rival theories have been proposed about the event that sparked this period, such as a collapse of the North American ice sheets, a major volcanic eruption, or a solar flare.

 

However, in a study published in The Journal of Geology, an international group of scientists analyzing existing and new evidence have determined a cosmic impact event, such as a comet or meteorite, to be the only plausible hypothesis to explain all the unusual occurrences at the onset of the Younger Dryas period.

 

Researchers from 21 universities in 6 countries believe the key to the mystery of the Big Freeze lies in nanodiamonds scattered across Europe, North America, and portions of South America, in a 50-million-square-kilometer area known as the Younger Dryas Boundary (YDB) field.

 

Microscopic nanodiamonds, melt-glass, carbon spherules, and other high-temperature materials are found in abundance throughout the YDB field, in a thin layer located only meters from the Earth’s surface. Because these materials formed at temperatures in excess of 2200 degrees Celsius, the fact they are present together so near to the surface suggests they were likely created by a major extraterrestrial impact event.

 

In addition to providing support for the cosmic impact event hypothesis, the study also offers evidence to reject alternate hypotheses for the formation of the YDB nanodiamonds, such as by wildfires, volcanism, or meteoric flux.

 

The team’s findings serve to settle the debate about the presence of nanodiamonds in the YDB field and challenge existing paradigms across multiple disciplines, including impact dynamics, archaeology, paleontology, limnology, and palynology.

 

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Bernhard H. Schmitz's curator insight, September 16, 3:33 AM

And where is the center of the YDB field?

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Dinosaurs shrank to evolve into birds over a 50 million years time span

Dinosaurs shrank to evolve into birds over a 50 million years time span | Amazing Science | Scoop.it

Huge meat-eating dinosaurs (Theropods) underwent 12 stages of miniaturization and shrank steadily over 50 million years to evolve into small, flying birds, researchers say. The branch of theropod dinosaurs which gave rise to modern birds decreased inexorably in size from 163kg beasts that roamed the land, to birds weighing less than 1kg over the period.


The radical transformation began around 200 million years ago and was likely driven by a move to the trees where creatures with smaller, lighter bodies and other features, such as large eyes for 3D vision, fared better than others.


Scientists pieced together the dinosaurs' sustained shrinkage after analysing more than 1,500 anatomical features of 120 species of theropods and early birds.


The evolutionary tree reveals that the theropod ancestors of modern birds underwent 12 substantial decreases in size that led to archaeopteryx, the earliest known bird on Earth. The rate at which they evolved distinct features, such as feathers, wings and wishbones, was four times faster than adaptations in other dinosaurs.


"Birds evolved through a unique phase of sustained miniaturisation in dinosaurs," said Michael Lee at the University of Adelaide. "Being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and fly. Ultimately, this evolutionary flexibility helped birds survive the deadly meteorite impact which killed off all their dinosaurian cousins," he added. The study is published in the journal, Science.


The steady reduction in size saw the two-legged land-based theropods evolve new bird-like features, including shorter snouts, smaller teeth and insulating feathers.


Gareth Dyke, a vertebrate palaeontologist and co-author of the study at Southampton University said: "The dinosaurs most closely related to birds are all small, and many of them, such as the aptly named Microraptor, had some ability to climb and glide."


In an accompanying article, Michael Benton at Bristol University, said that the long-term trend that led to modern birds was probably shaped by the animals taking up in new habitats. "The crucial driver may have been a move to the trees, perhaps to escape from predation or to exploit new food resources," he writes.

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Newly declared species may have been the largest flying bird that ever lived

Newly declared species may have been the largest flying bird that ever lived | Amazing Science | Scoop.it
After decades with the title, an extinct bird loses its claim to the widest wing span in history.


When South Carolina construction workers came across the giant, winged fossil at the Charleston airport in 1983, they had to use a backhoe to pull the bird, which lived about 25 million years ago, up from the earth.


But if the bird was actually a brand-new species, researchers faced a big question: Could such a large bird, with a wingspan of 20 to 24 feet, actually get off the ground? After all, the larger the bird, the less likely its wings are able to lift it unaided.


The answer came from Dan Ksepka, paleontologist and science curator at the Bruce Museum in Greenwich, Conn.


He modeled a probable method of flight for the long-extinct bird, named as a new species this week in the Proceedings of the National Academy of Sciences. If Ksepka’s simulations are correct, Pelagornis sandersi would be the largest airborne bird ever discovered.


Pelagornis sandersi relied on the ocean to keep it aloft. Similar in many ways to a modern-day albatross — although with at least twice the wingspan and very different in appearance, Ksepka said — the bird probably needed a lot of help to fly. It had to run downhill into a head wind, catching the air like a hang glider. Once airborne, it relied on air currents rising from the ocean to keep it gliding.

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Fossilized nuclei and chromosomes of 180 million-year-old fern nearly identical to modern relative

Fossilized nuclei and chromosomes of 180 million-year-old fern nearly identical to modern relative | Amazing Science | Scoop.it

A trio of researchers in Sweden has unearthed a fossilized fern that has been dated to 180 million years ago, that remarkably, is in near pristine condition. Benjamin Bomfleur and Stephen McLoughlin, of the Swedish Museum of Natural History and Vivi Vajda of Lund University, report in their paper published in the journal Science that they discovered the fossil in a bed of volcanic rock near Korsaröd in Sweden, and found it so well preserved that microscopic analysis revealed that they could make out its DNA structure.


The calcified stem of a royal fern dating back to the early Jurassic period was apparently preserved by mineral precipitation from hydrothermal brines as they rapidly crystalized, trapping the fern, which was clearly alive at the time, encasing it in an airtight environment. Although very small (just 5.8 x 4.1 cm) the fossil was so well preserved that the researchers were still able to make out cell cytoplasm, nuclei and even chromosomes.


Curious, the team measured the sub-cellular parts of the fossilized plant and compared them to those of a modern relative, the cinnamon fern (Osmundastrum cinnamomeum), which has already earned the title of a "living fossil" due to prior research that revealed its origins could be dated back to 75 million years ago. In so doing they discovered that the number of chromosomes and indeed the DNA content itself was a very close match—so close that the team dubbed them a "paramount example of evolutionary stasis." Remarkably, the plant hasn't changed much at all over a period of 180 million years. When it lived, it likely looked much like the bright green cinnamon fern (though they turn to cinnamon color later in life) of today, growing to a height of one to five feet with spreading fronds reaching six to eight inches. The team suggests the specimen provides exceptional insight into how life can evolve over geologic time.

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When Trilobites Ruled the World

When Trilobites Ruled the World | Amazing Science | Scoop.it
The remains of trilobites, a diverse group of marine animals much older than dinosaurs, are remarkably well preserved, providing fresh insights of their anatomies and social behavior.


Trilobites may be the archetypal fossils, symbols of an archaic world long swept beneath the ruthless road grader of time. But we should all look so jaunty after half a billion years.


At the Smithsonian’s National Museum of Natural History, Brian T. Huber, chairman of paleobiology, points to a flawless specimen of Walliserops, a five-inch trilobite that swam the Devonian seas around what is now Morocco some 150 million years before the first dinosaurs hatched. With its elongated, triple-tined head horn and a bristle brush of spines encircling its lower body, the trilobite could be a kitchen utensil for Salvador Dalí. Nearby is the even older Boedaspis ensifer, its festive nimbus of spiny streamers pointing every which way like the ribbons of a Chinese dancer.


In most trilobites, each compound orb held hundreds of tiny calcite lenses, arranged in a tightknit honeycomb pattern, like the eye of a fly. But fairly late in trilobite evolution one group developed a different sort of eye, composed of a smaller number of larger, separated calcite lenses. As they described last spring in the journal Scientific ReportsBrigitte Schoenemann of the Universities of Cologne and Bonn in Germany and Euan N. K. Clarkson of the University of Edinburgh, used advanced scanning techniques, including synchrotron radiation, to examine specimens of these later, larger-lensed trilobite eyes. On the back of the lenses, the scientists were astonished to see traces of the sensory receptor cells that once linked the eyes to the brain. “It was extraordinary,” Dr. Schoenemann said. “As far as we know, these are the oldest receptor cells that have ever been seen in any fossil animal.”


Analyzing the microstructure of the receptor tracings, the researchers concluded that the eyes were designed to work optimally in lowlight, murky conditions, a sign that some trilobites were turning reclusive, descending to deeper waters or burrowing farther into the mud to escape the proliferation of toothy marine predators and new crustacean competitors. Toward the end of the Paleozoic Era, the once-thriving trilobite tribe had been reduced to a scattering of species. And they, too, vanished in the great Permian extinction 252 million years ago.


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Confirmed: An Asteroid Killed the Dinosaurs –– Date confirmed to accuracy of +/- 11,000 years

Confirmed: An Asteroid Killed the Dinosaurs –– Date confirmed to accuracy of +/- 11,000 years | Amazing Science | Scoop.it

Scientists have unearth credible evidence to confirm a large asteroid was responsible for the extinction of the dinosaurs over 66 million years ago, it has been announced. This particular extinction event, which paved the way for the evolution of our species, has been attributed to several different things over the years. From climate change, a nuclear winter caused by basaltic lava eruptions of massive volcanoes in western India, an influx of radiation from a nearby supernova explosion (or perhaps a gamma-ray burst) to finally, an asteroid impact, which has been a favorite of biologist and paleontologist over the course of the past few decades.


According to Paul Renne, the director at Berkeley University’s Geochronology Center in California, the asteroid impact was quite likely one of several contributing factors to the downfall of the prehistoric animals, as many of them were already on their way to extinction; however, Renne claims that this was the main catalyst that “pushed Earth past the tipping point.”


The collision was never in question, but the exact date of it is. Scientists have been trying to determine if the impact took place more than 300,000 years after the last of the dinosaurs had already died off in the Cretaceous-Tertiary extinction event, which is where Renne and his team comes in: Using high-precision radiometric dating analysis, in this case “argon-argon dating,” the team were able to determine the most precise date yet of the impact: 66,038,000 years ago – give or take 11,000, which coincides with the impact of an asteroid or a comet in the Caribbean off the Yucatan coast of Mexico. “We have shown that these events are synchronous to within a gnat’s eyebrow,” Renne continued. Potassium-argon dating is perhaps, one of the most reliable means of determine how long a sample of materials have been decaying, as it utilizes the fact that potassium, a naturally radioactive element, decays into argon with regularity.


It only takes a relatively small asteroid to cause quite a bit of destruction on our planet, as any object large enough to survive the descent through Earth’s atmosphere would acquire quite a bit of kinetic energy before it hits the surface of the planet, traveling at VERY fast speeds. Just to throw out one example of this, if an object had a diameter of about 10 kilometers and was traveling at speeds between [approximately] 15 to 20 kilometers per second, it would have a kinetic energy equal to 300 million nuclear bombs, going off simultaneously.


Almost instantly after the impact, the Earth would undergo rapid changes, including; “intense blinding light, severe radiation burns, a crushing blast wave, lethal balls of hot glass, winds with speeds of hundreds of kilometers per hour, and flash fires.” The rubble would be forced into the stratosphere, where it would block a majority of the sunlight from the plants and animals on the ground, which becomes problematic for the photosynthesis plants must undergo to derive energy to survive. With no plants converting sunlight into energy, our oxygen levels would decrease dramatically. I don’t have to explain why that is not an ideal situation to find ourselves in.


The asteroid that hit our planet at the end of the Mesozoic Era was almost 6 miles (10 km) across, generating more energy than nearly 100 trillion tons of TNT, which is more than a billion times more energetic than the bombs that destroyed Nagasaki and Hiroshima during WWII — ultimately leaving behind a crater named Chicxulub, which is more than 110 miles (180 kilometers) wide.

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New Tyrannosaur named 'Pinocchio rex' discovered

New Tyrannosaur named 'Pinocchio rex' discovered | Amazing Science | Scoop.it

The ferocious carnivore, nine metres long with a distinctive horny snout, was a cousin of Tyrannosaurus rexIts skeleton was dug up in a Chinese construction site and identified by scientists at Edinburgh University, UK.


The 66-million-year-old predator, officially named Qianzhousaurus sinensis, is described in Nature Communications"Pinocchio rex" looked very different to other tyrannosaurs. "It had the familiar toothy grin of T. rex, but its snout was long and slender, with a row of horns on top," said Edinburgh's Dr Steve Brusatte.


"It might have looked a little comical, but it would have been as deadly as any other tyrannosaur, and maybe even a little faster and stealthier.

"We thought it needed a nickname, and the long snout made us think of Pinocchio's long nose."


Researchers now think several different tyrannosaurs lived and hunted alongside each other in Asia during the late Cretaceous Period, the last days of the dinosaurs.


The enormous Tarbosaurus (up to 13m) had deep and powerful jaws likeT. rex - strong enough to crush the bones of giant herbivores. The thinner teeth and lighter skeleton of Qianzhousaurus suggest it hunted smaller creatures, such as lizards and feathered dinosaurs. But at nine metres tall and weighing almost a tonne, it was still a gigantic carnivore.


The discovery of "Pinocchio" settles an argument over a series of strange new fossil finds. In recent years, two tyrannosaurs with unusually prominent proboscises were dug up in Mongolia, and named AlioramusThe horny-snouted predators appeared to come from an entirely new branch of the tyrannosaur family.


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500 Million-Year-Old Fossilized Embryos Found

500 Million-Year-Old Fossilized Embryos Found | Amazing Science | Scoop.it
Researchers at the University of Missouri have discovered rare, fossilized embryos that may provide valuable insight into a time of rapid expansion and diversification among the world's first organisms, according to a release from the school.


Known as the "Cambrian explosion," most of the world's marine 

invertebrates first appeared in the fossil record during this period. While much of the record is comprised of skeletal structures - which may or may not give researchers an accurate picture of prehistoric organisms - the University of Missouri find includes previously undiscovered soft-tissue fossils, which could help with future interpretations of evolutionary history.


"Before the Ediacaran and Cambrian Periods, organisms were unicellular and simple," said James Schiffbauer, assistant professorof geological sciences at the University of Missouri. "The Cambrian Period, which occurred between 540 million and 485 million years ago, ushered in the advent of shells."


He said the shells and exoskeletons become fossilized over time, giving scientists clues into how organisms existed millions of years ago. He added that the development of shells provided "protection and structural integrity for organisms."


Schiffbauer's work focuses on harder-to-find, soft-tissue organisms that were not preserved as well and, thus, are less plentiful. His team, which includes Missouri University doctoral student Jesse Broce, now is studying fossilized embryos in rocks that provide rare opportunities to study the origins and developmental biology of early animals during the Cambrian explosion.


Broce collected fossils from the lower Cambrian Shuijingtuo Formation in the Hubei Province in southern China and analyzed samples to determine the chemical makeup of the rocks. Soft tissue fossils have different chemical patterns than harder, skeletal remains, allowing researchers to identify the processes that contributed to their preservation.

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Was a methane-spewing microbe the cause for Earth's worst mass extinction

Was a methane-spewing microbe the cause for Earth's worst mass extinction | Amazing Science | Scoop.it

A microbe that spewed humongous amounts of methane into Earth's atmosphere triggered a global catastrophe 252 million years ago that wiped out upwards of 90 percent of marine species and 70 percent of land vertebrates.


That's the hypothesis offered on Monday by researchers aiming to solve one of science's enduring mysteries: what happened at the end of the Permian period to cause the worst of the five mass extinctions in Earth's history.


The scale of this calamity made the one that doomed the dinosaurs 65 million years ago - a six-mile wide asteroid smacking the planet - seem like a picnic by comparison.


The implicated microbe, Methanosarcina, is a member of a kingdom of single-celled organisms distinct from bacteria called archaea that lack a nucleus and other usual cell structures.


"I would say that the end-Permian extinction is the closest animal life has ever come to being totally wiped out, and it may have come pretty close," said Massachusetts Institute of Technology biologist Greg Fournier, one of the researchers.


"Many, if not most, of the surviving groups of organisms barely hung on, with only a few species making it through, many probably by chance," Fournier added.


Previous ideas proposed for the Permian extinction include an asteroid and large-scale volcanism. But these researchers suggest a microscope would be needed to find the actual culprit.


Methanosarcina grew in a frenzy in the seas, disgorging huge quantities of methane into Earth's atmosphere, they said.

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Scientists finally solve the mystery of New Zealand's Moas disappearanc

Scientists finally solve the mystery of  New Zealand's Moas disappearanc | Amazing Science | Scoop.it

Scientists have long argued about what caused the extinction of many species of megafauna—giant animals including mammoths, mastodons, and moas—beginning between 9000 and 13,000 years ago, when humans began to spread around the world. Often, the animals disappeared shortly after humans arrived in their habitats, leading some researchers to suggest that we exterminated them by overhunting. But other scientists have pointed to natural causes, including volcanic eruptions, disease, and climate change at the end of last Ice Age, as the key reasons for these species’ demise. The moas present a particularly interesting case, researchers say, because they were the last of the giant species to vanish, and they did so recently, when a changing climate was no longer a factor. But did other natural causes set them on a path to oblivion, as some scientists proposed in a recent paper?


Morten Allentoft, an evolutionary biologist at the University of Copenhagen, doubted this hypothesis. Archaeologists know that the Polynesians who first settled New Zealand ate moas of all ages, as well as the birds’ eggs. With moa species ranging in size from 12 to 250 kilograms, the birds—which had never seen a terrestrial mammal before people arrived—offered sizable meals. “You see heaps and heaps of the birds’ bones in archaeological sites,” Allentoft says. “If you hunt animals at all their life stages, they will never have a chance.”


Using ancient DNA from 281 individual moas from four different species, including Dinornis robustus (at 2 meters, the tallest moa, able to reach foliage 3.6 meters above the ground), and radiocarbon dating, Allentoft and his colleagues set out to determine the moas’ genetic and population history over the last 4000 years. The moa bones were collected from five fossil sites on New Zealand’s South Island, and ranged in age from 12,966 to 602 years old. The researchers analyzed mitochondrial and nuclear DNA from the bones and used it to examine the genetic diversity of the four species.


Usually, extinction events can be seen in a species’ genetic history; as the animals’ numbers dwindle, they lose their genetic diversity. But the team’s analysis failed to find any sign that the moas’ populations were on the verge of collapse. In fact, the scientists report that the opposite was true: The birds’ numbers were stable during the 4000 years prior to their extinction, they report online today in the Proceedings of the National Academy of Sciences. Populations of D. robustus even appear to have been slowly increasing when the Polynesians arrived. No more than 200 years later, the birds had vanished. “There is no trace of” their pending extinction in their genes, Allentoft says. “The moa are there, and then they are gone.”


The paper presents an “impressive amount of evidence” that humans alone drove the moa extinct, says Trevor Worthy, an evolutionary biologist and moa expert at Flinders University in Adelaide, Australia, who was not involved with the research. “The inescapable conclusion is these birds were not senescent, not in the old age of their lineage and about to exit from the world. Rather they were robust, healthy populations when humans encountered and terminated them.” Still, he doubts even Allentoft’s team’s “robust data set” will settle the debate about the role people played in the birds’ extinction, simply because “some have a belief that humans would not have” done such a thing.

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Deborah Verran's comment, March 18, 1:16 AM
They had the biggest "drumsticks" ever seen....hence the attraction to the humans who settled in New Zealand!
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One of the Largest Known Predatory Dinosaurs in Europe Found, Torvosaurus gurneyi

One of the Largest Known Predatory Dinosaurs in Europe Found, Torvosaurus gurneyi | Amazing Science | Scoop.it

A new species of dinosaur found in Portugal likely used brute force to take down prey, a new study says. Torvosaurus gurneyi, perhaps the biggest predatory dinosaur yet found in Europe, was an especially strong carnivore that likely used its four-inch-long (ten-centimeter-long), blade-shaped teeth and sharp-clawed forearms to rip into its prey.


The 32-foot-long (10-meter-long) beast roamed the Iberian Peninsula—home to modern-day Spain, Portugal, Andorra, and parts of France—about 150 million years ago during the late Jurassic period.


Christophe Hendrickx, a Ph.D. student at the New University of Lisbon in Portugal, discovered the giant while studying bones believed to belong to Torvosaurus tanneri, a related species that lived in North America's Rocky Mountain region around the same time. When the continents were connected as part of the supercontinent Pangaea, dinosaurs could potentially have migrated from North America to Europe or vice versa. But upon closer inspection, these bones—taken from the fossil-rich Lourinhã Formation in west-central Portugal—didn't look like T. tanneri. For one, the upper jaw had fewer teeth, this bone and the tail vertebrae differed—all suggesting that Hendrickx and supervisor Octávio Mateus had revealed a new species.

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Chaohusaurus Fossil Shows Oldest Live Reptile Birth

Chaohusaurus Fossil Shows Oldest Live Reptile Birth | Amazing Science | Scoop.it

Recent excavations in south Majiashan, Anhui, China, yielded more than 80 new ichthyosaur skeletons. Among the specimens was a partial skeleton that contained embryos. According to Dr. Chen and colleagues, the fossil belongs to the ichthyosaur Chaohusaurus, which is the oldest of Mesozoic marine reptiles. This viviparous creature lived around 248 million years ago. It had a lizard-like appearance and was one of the smallest ichthyosaurs (up to 1.8 m long).


The new fossil was associated with three embryos and neonates: one inside the mother, another exiting the pelvis-with half the body still inside the mother-and the third outside of the mother. The headfirst birth posture of the second embryo indicates that live births in ichthyosaurs may have taken place on land, instead of in the water, as some studies have previously suggested.


“The study reports the oldest vertebrate fossil to capture the ‘moment’ of live-birth, with a baby emerging from the pelvis of its mother. The 248-million-year old fossil of an ichthyosaur suggests that live-bearing evolved on land and not in the sea,” said Dr Ryosuke Motani from the University of California, Davis, the first author of a paper published in the journal PLoS ONE.


The Chaohusaurus fossil may also contain the oldest fossil embryos of Mesozoic marine reptile, about 10 million years older than those indicated on previous records.


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