This 13 December 2019 video says about itself:
The sharklike Helicoprion lived 275 million years ago and could slice its prey in two with its buzz saw jaw.
This 13 December 2019 video says about itself:
The sharklike Helicoprion lived 275 million years ago and could slice its prey in two with its buzz saw jaw.
This 23 August 2019 video says about itself:
From New York University in the USA:
Researchers unearth ‘new’ mass-extinction
New analysis brings total of species extinctions to six
September 9, 2019
A team of scientists has concluded that earth experienced a previously underestimated severe mass-extinction event, which occurred about 260 million years ago, raising the total of major mass extinctions in the geologic record to six.
“It is crucial that we know the number of severe mass extinctions and their timing in order to investigate their causes,” explains Michael Rampino, a professor in New York University’s Department of Biology and a co-author of the analysis, which appears in the journal Historical Biology. “Notably, all six major mass extinctions are correlated with devastating environmental upheavals — specifically, massive flood-basalt eruptions, each covering more than a million square kilometers with thick lava flows.”
Scientists had previously determined that there were five major mass-extinction events, wiping out large numbers of species and defining the ends of geological periods: the end of the Ordovician (443 million years ago), the Late Devonian (372 million years ago), the Permian (252 million years ago), the Triassic (201 million years ago), and the Cretaceous (66 million years ago). And, in fact, many researchers have raised concerns about the contemporary, ongoing loss of species diversity — a development that might be labeled a “seventh extinction” because such a modern mass extinction, scientists have predicted, could end up being as severe as these past events.
The Historical Biology work, which also included Nanjing University’s Shu-zhong Shen, focused on the Guadalupian, or Middle Permian period, which lasted from 272 to about 260 million years ago.
Here, the researchers observe, the end-Guadalupian extinction event — which affected life on land and in the seas — occurred at the same time as the Emeishan flood-basalt eruption that produced the Emeishan Traps, an extensive rock formation, found today in southern China. The eruption’s impact was akin to those causing other known severe mass extinctions, Rampino says.
“Massive eruptions such as this one release large amounts of greenhouse gases, specifically carbon dioxide and methane, that cause severe global warming, with warm, oxygen-poor oceans that are not conducive to marine life,” he notes.
“In terms of both losses in the number of species and overall ecological damage, the end-Guadalupian event now ranks as a major mass extinction, similar to the other five,” the authors write.
This May 2015 video says about itself:
Ancestral Evolution – Ichthyostega to Varanops
It takes over 3 billion years for our ancestor to evolve from a single cell to a foot-long armoured fish. Our future looks bleak but natural selection throws us a lifeline. Over millions of years and thousands of generations, our body adapts until we do something no fish has done before, breathe air! The air travels into a new organ, a lung. Take a breath and remember it’s because a monster fish chased our ancestor into stagnant water forcing them to breathe air. We’re Ichthyostega, we can breathe air or water, closing off our windpipe to switch between lungs and gills. Today our gills are gone but the mechanism remains and sometimes it spasms giving us the hiccups. 365 million years ago we stick our head out of the water, there’s a swamp behind us, paradise ahead, the choice is simple but the consequences are immense. We pull ourselves out of the water and change the course of history.
Permian lizard-like animal suffered from a bone condition similar to Paget’s disease
Susceptibility to this type of disease may extend back to the Early Permian
August 7, 2019
A lizard-like animal that lived 289 million years ago suffered from a bone condition similar to Paget’s disease, according to a study published August 7, 2019 in the open-access journal PLOS ONE by Yara Haridy of the Museum für Naturkunde in Berlin and colleagues. This is the most ancient known case of such a disease.
The animal in question belonged to an extinct group of lizard-like creatures called varanopids, relatives of the earliest ancestors of mammals or reptiles.
It is still uncertain whether varanopids were ‘mammal-like reptiles’, ancestral to mammals, or rather diapsids, ancestral to lizards, dinosaurs, etc.
The authors identified the disease in an isolated pair of tail vertebrae discovered in an Early Permian cave at Richards Spur, Oklahoma. Micro-CT scanning allowed examination of both the external and internal structure of the elements, revealing that in some places the bone had been thinned by abnormally high levels of reabsorption, while in other areas excessive bone growth had resulted in abnormal bone thickening and the ultimate fusion of the two vertebrae.
According to the researchers, this condition is most similar to Paget’s disease, a bone metabolic disorder marked by a breakdown in communication between bone building cells and bone destroying cells. Paget’s disease is commonly seen today in the hips and vertebrae of humans and has been diagnosed in other living mammals and reptiles as well as one Early Jurassic dinosaur fossil. The disease has been linked to both genetic and viral factors, though its precise cause remains controversial.
With only two vertebrae preserved, it is impossible to say how widespread the disease was in this animal’s body. If it was restricted to the tail, the animal may only have suffered minor pain and stiffness. This discovery marks the oldest known occurrence of a Paget-like disease and suggests that susceptibility to such disorders was already present in our early Permian cousins.
Haridy adds: “Paleopathology is the study of ancient diseases, here we scanned a pair of fused tail bones from a permian (280 million years ago) Varanopid (a superficially-lizard like animal), what we found was evidence of a bone disease similar to modern day Paget’s disease. This enigmatic disease is still not well understood in humans, however finding something similar in an ancient animal likely links it to something deep in our bone biology. This study is a great example of how when palaeontologists have well preserved fossils we can tell a lot more than just what animals were present, we can explore their biology, physiology and even what diseases ailed them!”
This 15 September 2015 video from the USA says about itself:
Around 252 millions years ago life on Earth collapsed in a unprecedented fashion as more than 96 percent of marine species and 70 percent of land species disappeared.
The cause of this severe extinction has been a mystery, until now. (Learn more here. MIT researchers have now determined the Siberian Traps erupted at the right time and for the right duration to have been a likely trigger for the end-Permian extinction.
Video produced and edited by Melanie Gonick/MIT
Additional footage and stills: Henrik Svensen, Scott Simper and Seth Burgess
Music sampled from “Out” by Ryan Cross
From the University of Cincinnati in the USA:
New evidence suggests volcanoes caused biggest mass extinction ever
Mercury found in ancient rock around the world supports theory that eruptions caused ‘Great Dying’ 252 million years ago.
April 15, 2019
Researchers say mercury buried in ancient rock provides the strongest evidence yet that volcanoes caused the biggest mass extinction in the history of the Earth.
The extinction 252 million years ago was so dramatic and widespread that scientists call it “the Great Dying.” The catastrophe killed off more than 95 percent of life on Earth over the course of hundreds of thousands of years.
Paleontologists with the University of Cincinnati and the China University of Geosciences said they found a spike in mercury in the geologic record at nearly a dozen sites around the world, which provides persuasive evidence that volcanic eruptions were to blame for this global cataclysm.
The study was published this month in the journal Nature Communications.
The eruptions ignited vast deposits of coal, releasing mercury vapor high into the atmosphere. Eventually, it rained down into the marine sediment around the planet, creating an elemental signature of a catastrophe that would herald the age of dinosaurs.
“Volcanic activities, including emissions of volcanic gases and combustion of organic matter, released abundant mercury to the surface of the Earth,” said lead author Jun Shen, an associate professor at the China University of Geosciences.
The mass extinction occurred at what scientists call the Permian-Triassic Boundary. The mass extinction killed off much of the terrestrial and marine life before the rise of dinosaurs. Some were prehistoric monsters in their own right, such as the ferocious gorgonopsids that looked like a cross between a sabre-toothed tiger and a Komodo dragon.
The eruptions occurred in a volcanic system called the Siberian Traps in what is now central Russia. Many of the eruptions occurred not in cone-shaped volcanoes but through gaping fissures in the ground. The eruptions were frequent and long-lasting and their fury spanned a period of hundreds of thousands of years.
“Typically, when you have large, explosive volcanic eruptions, a lot of mercury is released into the atmosphere,” said Thomas Algeo, a professor of geology in UC’s McMicken College of Arts and Sciences.
“Mercury is a relatively new indicator for researchers. It has become a hot topic for investigating volcanic influences on major events in Earth’s history,” Algeo said.
Researchers use the sharp fossilized teeth of lamprey-like creatures called conodonts to date the rock in which the mercury was deposited. Like most other creatures on the planet, conodonts were decimated by the catastrophe.
The eruptions propelled as much as 3 million cubic kilometers of ash high into the air over this extended period. To put that in perspective, the 1980 eruption of Mount St. Helens in Washington sent just 1 cubic kilometer of ash into the atmosphere, even though ash fell on car windshields as far away as Oklahoma.
In fact, Algeo said, the Siberian Traps eruptions spewed so much material in the air, particularly greenhouse gases, that it warmed the planet by an average of about 10 degrees centigrade.
The warming climate likely would have been one of the biggest culprits in the mass extinction, he said. But acid rain would have spoiled many bodies of water and raised the acidity of the global oceans. And the warmer water would have had more dead zones from a lack of dissolved oxygen.
“We’re often left scratching our heads about what exactly was most harmful. Creatures adapted to colder environments would have been out of luck,” Algeo said. “So my guess is temperature change would be the No. 1 killer. Effects would exacerbated by acidification and other toxins in the environment.”
Stretching over an extended period, eruption after eruption prevented the Earth’s food chain from recovering.
“It’s not necessarily the intensity but the duration that matters,” Algeo said. “The longer this went on, the more pressure was placed on the environment.”
Likewise, the Earth was slow to recover from the disaster because the ongoing disturbances continued to wipe out biodiversity, he said.
Earth has witnessed five known mass extinctions over its 4.5 billion years.
Scientists used another elemental signature — iridium — to pin down the likely cause of the global mass extinction that wiped out the dinosaurs 65 million years ago. They believe an enormous meteor struck what is now Mexico.
The resulting plume of superheated earth blown into the atmosphere rained down material containing iridium that is found in the geologic record around the world.
Shen said the mercury signature provides convincing evidence that the Siberian Traps eruptions were responsible for the catastrophe. Now researchers are trying to pin down the extent of the eruptions and which environmental effects in particular were most responsible for the mass die-off, particularly for land animals and plants.
Shen said the Permian extinction could shed light on how global warming today might lead to the next mass extinction. If global warming, indeed, was responsible for the Permian die-off, what does warming portend for humans and wildlife today?
“The release of carbon into the atmosphere by human beings is similar to the situation in the Late Permian, where abundant carbon was released by the Siberian eruptions,” Shen said.
Algeo said it is cause for concern.
“A majority of biologists believe we’re at the cusp of another mass extinction — the sixth big one. I share that view, too,” Algeo said. “What we should learn is this will be serious business that will harm human interests so we should work to minimize the damage.”
People living in marginal environments such as arid deserts will suffer first. This will lead to more climate refugees around the world.
“We’re likely to see more famine and mass migration in the hardest hit places. It’s a global issue and one we should recognize and proactively deal with. It’s much easier to address these problems before they reach a crisis.”
This March 2018 video says about itself:
‘The Great Dying’ Was Our Worst Extinction Ever, And It Could Happen Again
What exactly caused the greatest extinction on earth? New research may finally hold the answer to this long time mystery.
From the University of Nebraska-Lincoln in the USA:
Earth’s largest extinction event likely took plants first
January 31, 2019
Summary: New evidence from the cliffsides of Australia suggests that Earth’s largest extinction event — a volcanic cataclysm occurring roughly 252 million years ago — extinguished plant life long before many animal counterparts.
Little life could endure the Earth-spanning cataclysm known as the Great Dying, but plants may have suffered its wrath long before many animal counterparts, says new research led by the University of Nebraska-Lincoln.
About 252 million years ago, with the planet’s continental crust mashed into the supercontinent called Pangaea, volcanoes in modern-day Siberia began erupting. Spewing carbon and methane into the atmosphere for roughly 2 million years, the eruption helped extinguish about 96 percent of oceanic life and 70 percent of land-based vertebrates — the largest extinction event in Earth’s history.
“That’s big news”, said lead author Christopher Fielding, professor of Earth and atmospheric sciences. “People have hinted at that, but nobody’s previously pinned it down. Now we have a timeline.”
The researchers reached the conclusion by studying fossilized pollen, the chemical composition and age of rock, and the layering of sediment on the southeastern cliffsides of Australia. There they discovered surprisingly high concentrations of nickel in the Sydney Basin’s mud-rock — surprising because there are no local sources of the element.
Tracy Frank, professor and chair of Earth and atmospheric sciences, said the finding points to the eruption of lava through nickel deposits in Siberia. That volcanism could have converted the nickel into an aerosol that drifted thousands of miles southward before descending on, and poisoning, much of the plant life there. Similar spikes in nickel have been recorded in other parts of the world, she said.
“So it was a combination of circumstances,” Fielding said. “And that’s a recurring theme through all five of the major mass extinctions in Earth’s history.”
If true, the phenomenon may have triggered a series of others: herbivores dying from the lack of plants, carnivores dying from a lack of herbivores, and toxic sediment eventually flushing into seas already reeling from rising carbon dioxide, acidification and temperatures.
‘It Lets Us See What’s Possible’
One of three married couples on the research team, Fielding and Frank also found evidence for another surprise. Much of the previous research into the Great Dying — often conducted at sites now near the equator — has unearthed abrupt coloration changes in sediment deposited during that span.
Shifts from grey to red sediment generally indicate that the volcanism’s ejection of ash and greenhouse gases altered the world’s climate in major ways, the researchers said. Yet that grey-red gradient is much more gradual at the Sydney Basin, Fielding said, suggesting that its distance from the eruption initially helped buffer it against the intense rises in temperature and aridity found elsewhere.
Though the time scale and magnitude of the Great Dying exceeded the planet’s current ecological crises, Frank said the emerging similarities — especially the spikes in greenhouse gases and continuous disappearance of species — make it a lesson worth studying.
“Looking back at these events in Earth’s history is useful because it lets us see what’s possible,” she said. “How has the Earth’s system been perturbed in the past? What happened where? How fast were the changes? It gives us a foundation to work from — a context for what’s happening now.”
The researchers detailed their findings in the journal Nature Communications. Fielding and Frank authored the study with Allen Tevyaw, graduate student in geosciences at Nebraska; Stephen McLoughlin, Vivi Vajda and Chris Mays from the Swedish Museum of Natural History; Arne Winguth and Cornelia Winguth from the University of Texas at Arlington; Robert Nicoll of Geoscience Australia; Malcolm Bocking of Bocking Associates; and James Crowley of Boise State University.
The National Science Foundation and the Swedish Research Council funded the team’s work.
This 28 January 2019 video says about itself:
Edaphosaurus, meaning “pavement lizard” for dense clusters of teeth) is a genus of extinct edaphosaurid synapsid. It lived in what is now North America and Europe around 300 to 280 million years ago, during the late Carboniferous to early Permian periods.
Edaphosaurus is important as one of the earliest known large plant-eating (herbivorous) amniote tetrapods (four-legged land-living vertebrates). In addition to the large tooth plates in its jaws, the most characteristic feature of Edaphosaurus is a sail on its back which is unique in shape and morphology. Edaphosaurus species measured from 0.5 metres (1.6 ft) to almost 3.5 metres (11.5 ft) in length and weighed over 300 kilograms (660 lb).
Like its more famous relative Dimetrodon, Edaphosaurus had a sail-like fin that was supported by bones of the vertebral column. Edaphosaurus differs from Dimetrodon in having cross-bars on the spines that supported its fin. Edaphosaurus and other members of the Edaphosauridae evolved tall dorsal sails independently of sail-back members of the Sphenacodontidae. Dimetrodon and Secodontosaurus that lived at the same time are an unusual example of parallel evolution.