This 15 July 2016 video is the most recent one of the series.
From daily The Independent in Britain:
Dinosaur extinction mystery solved? Asteroid hit oil field causing smoke that filled Earth’s atmosphere
Temperatures would have plunged as soot blocked out the sun and the rain virtually stopped falling
Ian Johnston, Science Correspondent
21 minutes ago
The dinosaurs were wiped out 66 million years ago because a massive asteroid hit vast oil deposits in Mexico, sending thick black smoke into the atmosphere all over the world, according to a new study.
Soot blocked out the sun, causing the planet to cool significantly and experience devastating droughts.
The amount of sunlight would have fallen by up to 85 per cent, while the Earth would have cooled by as much as 16 degrees Celsius on land for about three years.
At the same time, rainfall would have fallen by up to 80 per cent causing extreme drought.
The six-mile-wide asteroid, which hit what is now the Yucatan Peninsula, created the third-largest crater on Earth, some 110 miles across.
It struck the Earth with the force of about a billion nuclear bombs of the size that destroyed the Japanese city of Hiroshima during World War Two.
Previously it was thought that the impact caused vapours of sulphuric acid in the sky, which reflected sunlight leading to global darkness, near-freezing conditions and widespread acid rain.
“Recent impact experiments and model calculations have demonstrated that condensed sulfuric acid aerosols cannot form and persist over long periods following asteroid impacts.”
It is estimated that just 12 per cent of life on land survived the chaos unleashed by the asteroid, but 90 per cent of freshwater species were able to ride out the sudden shock to the planet.
This video says about itself:
13 July 2016
A newly discovered meat-eating dinosaur that prowled Argentina 90 million years ago would have had a hard time using strong-arm tactics against its prey. That’s because the beast, though a fearsome hunter, possessed a pitifully puny pair of arms.
Scientists said on Wednesday they have unearthed fossils in northern Patagonia of a two-legged, up to 26-foot-long (8-meters-long) predator called Gualicho shinyae with arms only about 2 feet (60 cm) long, akin to a human child’s.
The fossils of Gualicho, named after an evil spirit feared by Patagonia’s indigenous Tehuelche people, were discovered in Argentina’s Rio Negro Province.
Gualicho and other carnivorous dinosaurs like Tyrannosaurus rex are part of a group called theropods that included Earth’s largest-ever land predators. But a curious thing happened during their many millions of years of evolution. For some, as they acquired huge body size and massive skulls, their arms and their number of fingers shrank.
From the Christian Science Monitor in the USA:
T. rex wasn’t the only one with those strange little arms
Paleontologists discover a new dinosaur with T. rex-like arms, but it’s not a tyrannosaur.
By Eva Botkin-Kowacki, Staff writer
July 13, 2016
Quick! Make like a T. rex.
What is the first step to mimicking the famous, fearsome dinosaur? After roaring, a person probably pulls both arms in, contorting them to make them tiny relative to the rest of the body, mashing the five fingers together to have just two digits on each hand. One of the most characteristic features of the iconic tyrant lizard dinosaur is its strange, seemingly uselessly small forelimbs.
But Tyrannosaurus rex wasn’t the only two-legged carnivorous dinosaur to sport such teeny, two-fingered arms.
“Theropods in general do this quite often,” Lindsay Zanno, head of the Paleontology Research Lab at the North Carolina Museum of Natural Sciences, tells The Christian Science Monitor in a phone interview. “There are a lot of different groups of theropods that tend to reduce the size of their hands and their arms or change the way that they’re used.”
And another one is joining the bunch.
Gualicho shinyae, discovered in Argentina in 2007, is named and described in a paper published Wednesday in the journal PLOS ONE.
This new dinosaur’s “arms are short – about 2 ft long – which is less than the length of the thigh bone, and they have weak muscle attachments and poorly developed articulations indicating they had little strength,” Peter Makovicky, associate curator of dinosaurs at the Field Museum of Natural History in Chicago who co-led the team that discovered Gualicho, describes in an email to the Monitor.
The fingers on the 90-million-year-old fossil are similar to those of tyrannosaurs. The thumb has a large claw while the second finger is more slender. A third finger has become so reduced that it is just a tiny bone in the flesh of the animal’s hand. …
Gualicho has weak little arms with just two functional fingers like T. rex, but the similarities pretty much stop there.
“This animal has a kind of mosaic of features. There are aspects of its skeleton that show some affinities with some groups of dinosaurs and some affinities with other groups of dinosaurs, although none of those are really tyrannosaurs,” study co-author Nathan Smith, associate curator in the Dinosaur Institute at the Natural History Museum of Los Angeles County, tells the Monitor in a phone interview.
But the “oddball” dinosaur, as Dr. Smith describes it, could help researchers figure out why so many diverse theropod dinosaurs have evolved similar, reduced forelimbs. …
Some scientists have suggested that humongous predatory dinosaurs would have evolved smaller arms because their skulls were used more readily to wrangle prey, she says.
There seems to be a pattern among tyrannosaurs, for example, in which the arms became shorter and the fingers fewer as the animals’ skulls and bodies became larger over generations, says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not part of the study, in an email to the Monitor. This would suggest that “the head was taking over many of the duties that the arms once had, like procuring and processing food.”
“Most theropods with reduced forelimbs, like tyrannosaurs, ceratosaurs, and carcharodontosaurs are clearly macropredators that rely on their massive skulls for hunting, so it seems likely that the same was true of Gualicho,” Makovicky says.
These diverse dinosaurs were likely under similar evolutionary pressures that lead to similarly reduced forelimbs. The feature would have evolved independently in the different groups, in a process called convergent evolution. …
The mosaic features of Gualicho “makes figuring out the evolutionary placement of this animal a little difficult,” Smith says.
Weighing an estimated 1,000 pounds, Gualicho appears to fit into the family neovenatoridae, a large-bodied branch of carnivorous theropod dinosaurs, Smith says, but it also seems to bear the closest resemblance to Deltadromeus, a large theropod from Africa.
But could a South American dinosaur be closely related to an African one?
Possibly. Scientists have previously noted a lot of similarities between dinosaurs unearthed in the Kem Kem Beds on the border of Morocco and Algeria, where Deltadromeus has been found, and the Huincul Formation in Argentina, where Guialicho was discovered, Smith says. “So it may not be surprising that these two carnivorous dinosaurs are close relatives.”
And at the time when Guialicho roamed the Earth, the two continents had only recently, geologically speaking, begun to separate as the supercontinent Gondwana broke up.
Translated from Dutch NOS TV:
Amateur paleontologist finds skull of prehistoric reptile
Amateur paleontologist Remco Bleeker was the lucky one who found the skull. Bleeker, in everyday life a concrete repairer, is pleased with the find. …
Bleeker brought the skull for examination to Germany, where it was found that it was a Lariosaurus.
In the quarry at Winterswijk Triassic limestone is extracted from rock layers from the Triassic geological period some 240 million years ago. In the quarry Bleeker also once found a peculiar fossil of a toothy marine animal. This fossil, which was seen by experts as a missing link was even named after him: the Palatodonta bleekeri.
The skull of the lariosaurus has been given the name of the hamlet where it was found. “The first is named after me. Now it was time to honor the quarry,” says Bleeker, who gave his find on loan to Museum TwentseWelle.
The name of the newly discovered species is Lariosaurus vosseveldensis; after Vosseveld hamlet.
See also here.
The scientific description of the new species is here.
This video says about itself:
26 August 2014
Ever wonder why the dinosaurs disappeared? HHMI BioInteractive investigates the cause of the mass extinction at the end of the Cretaceous period—and the clues come from paleontology, chemistry, physics, and biology.
This three-act film tells the story of the extraordinary detective work that solved one of the greatest scientific mysteries of all time. Explore the fossil evidence of these prehistoric animals, and other organisms that went extinct, through this lively educational video.
From daily The Independent in Britain today:
‘More data shows the extinction was more severe than previously believed’
Nearly every species of mammal was eradicated by the prehistoric asteroid which wiped out the dinosaurs, research suggests.
Around 93% of mammal species were made extinct by the strike, which took place in the Cretaceous period, more than 66 million years ago.
Examination of fossil records by scientists from the University of Bath determined that the asteroid’s impact had been much more severe than previously thought.
Past estimates have been much lower because some of the rarer species that were killed left a smaller fossil record, researchers said.
The University of Bath’s Dr Nick Longrich said: “The species that are most vulnerable to extinction are the rare ones, and because they are rare, their fossils are less likely to be found.
“The species that tend to survive are more common, so we tend to find them.
“The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed.”
It was also found the asteroid’s catastrophic effect for life on Earth was mitigated by species recovering rapidly.
Within 300,000 years, the number of species on the planet was double the amount that had existed before the mass extinction.
Due to the lack of sustenance resulting from the widespread destruction of vegetation and animals, it is thought that the largest living animal during the period would have been about the size of a cat.
Dr Longrich added: “Because mammals did so well after the extinction, we have tended to assume that it didn’t hit them as hard.
“It wasn’t low extinction rates, but the ability to recover and adapt in the aftermath that led the mammals to take over.”
Researchers analysed all known mammal species in North America from the end of the Cretaceous period to draw their conclusions.
The findings were published in the Journal of Evolutionary Biology.