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Fins of prehistoric fish reveal origins of the human hand – Investing.com

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By Will Dunham

WASHINGTON (Reuters) – Inside the stout fins of a fish that prowled the shallow waters of an estuary in what is now eastern Canada about 380 million years ago, scientists have found what they call the evolutionary origins of the human hand.

The researchers examined a remarkably complete fossil of a fish called Elpistostege watsoni that represents a pivotal stage in a landmark event in the history of life on Earth – the transition of fish to land vertebrates.

For this to occur, anatomical changes were needed including the evolution of hands and feet. Inside the tip of Elpistostege’s front fins – called pectoral fins – were tiny bones called radial bones arranged in a series of rows like digits – the precursor to fingers. These would have provided the flexibility for Elpistostege’s fin to bear weight on land.

“By looking at Elpistostege, it is important to realize that we, as human beings, are coming from a long line of evolution, that every part of our body, like our fingers, has a long evolutionary history,” said paleontologist Richard Cloutier of Université du Québec à Rimouski in Canada, lead author of the research published in the journal Nature.

“This is true for Homo sapiens but it is also true for all living organisms,” Cloutier added.

This marks the first time such traits have been found in a fish rather than in the earliest amphibians – the first land vertebrates – that later evolved from fish with sturdy fins like Elpistostege. It had two explicit digits and three other apparent digits.

More than five feet (1.6 meters) long, Elpistostege was primarily aquatic, with a crocodile-like body shape and flat triangular head, eyes atop the skull and numerous teeth around the jaws and in the palate. Its slender body was covered in thick scales and it had well-developed fins. It likely was the top predator in its brackish estuary ecosystem during the Devonian Period.

It is unclear whether it occasionally emerged onto land, but the structure of its fins would have enabled it to do so, said paleontologist and study co-author John Long of Flinders University in Australia. Its digits were still contained within the fin and not yet free moving like fingers.

Elpistostege was known only from partial fossils until this one was found in Miguasha National Park in Quebec province.

The four-limbed land animals that evolved from fish like Elpistostege are called tetrapods, a group now spanning amphibians, reptiles, birds and mammals including humans.

The digits of the 30,000-plus living species of tetrapods all share the same basic pattern found in Elpistostege. Like other similar fish, Elpistostege’s fin also has the precursors of tetrapod limb bones including the upper arm, forearm and wrist.

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article image Antarctica was home to a rainforest 90 million years ago – Digital Journal

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A team of researchers led by geoscientists from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany and scientists from Imperial College London, UK. have discovered fossil soil dating to the mid-Cretaceous Period, about 90 million years ago, suggesting that the climate was exceptionally warm at the time.

Their analysis of the preserved roots, pollen, and spores show that dense concentrations of atmospheric CO2 would have created much hotter global temperatures, melting polar ice sheets, and sending sea levels soaring to up to 170 meters (558 feet) higher than they are today. Their work was published in the journal Nature on April 1, 2020.

Co-author Professor Tina van de Flierdt, from the Department of Earth Science & Engineering at Imperial, said, per Science Daily: “The preservation of this 90-million-year-old forest is exceptional, but even more surprising is the world it reveals. Even during months of darkness, swampy temperate rainforests were able to grow close to the South Pole, revealing an even warmer climate than we expected.”

FS Polarstern in front of a mighty iceberg in Inner Pine Island Bay, West Antarctica.

JP Klages, Alfred Wegener Institute

Attention-grabbing sediment layer

During an expedition in 2017, aboard the RV Polarstern in the Amundsen Sea, researchers drilled deep underneath the seabed of West Antarctica, close to the location of the Pine Island and Thwaites glaciers, and only about 900 kilometers (560 miles) away from the South Pole.

What they pulled up from a depth of about 30 meters “quickly caught our attention. It clearly differed from the layers above it,” lead author Dr. Johann Klages, a geologist at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany, said in a press release.

“The first analyses indicated that, at a depth of 27 to 30 meters (88 to 98 ft) below the ocean floor, we had found a layer originally formed on land, not in the ocean.”

First author Dr. Johann P. Klages (AWI) and co-author Prof. Dr. Tina van de Flierdt (Imperial Colleg...

First author Dr. Johann P. Klages (AWI) and co-author Prof. Dr. Tina van de Flierdt (Imperial College London) try to remove heavily solidified sediment from the MeBo core catchers.

Thomas Ronge; Alfred Wegener Institute

No one has ever pulled a Cretaceous Period sample out of the ground from such a southern point on the planet before – but the research team was not prepared for what they would find out after a further examination of the sediment was done with X-ray computed tomography (CT) scans.

Back on land, the CT Scans revealed soil that was so well-preserved that it still contained traces of pollen, spores, and remnants of flowering plants. Even intact individual cell structures could be observed. This all pointed to the preserved remains of an ancient rainforest that existed in Antarctica approximately 90 million years ago.

“The numerous plant remains indicate that the coast of West Antarctica was, back then, a dense temperate, swampy forest, with many conifers and tree ferns similar to the forests found in New Zealand today,” says palaeoecologist Ulrich Salzmann from Northumbria University in the UK.

Station meeting of geologists and geophysicists in the sounder center of the FS Polarstern.

Station meeting of geologists and geophysicists in the sounder center of the FS Polarstern.

JP Klages, Alfred Wegener Institute

An interesting reason for the unprecedented find

So how could it have been possible for a rainforest to grow and thrive at the South Pole? We do know that the mid-Cretaceous was the heyday of the dinosaurs – but was also the Earth’s warmest period in the past 140 million years, with ocean temperatures thought to be as high as 95 degrees Fahrenheit.

Then, as now, the South Pole would have been subjected to four months of unyielding darkness during the Antarctic winter. How could this ancient rainforest thrive, deprived of the Sun for so long? Based on biological and geochemical data contained in the soil sample, researchers used modeling to reconstruct what the ancient climate of this long-gone forest region might have been like.

They found out that atmospheric CO2 levels would have needed to be significantly higher than scientists realized. It was a super-heated environment, with an average air temperature of around 12 degrees Celsius or 54 degrees Fahrenheit in the Antarctic.

“Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous was roughly 1,000 parts per million (ppm),” explains geoscientist Torsten Bickert from the University of Bremen in Germany. “But in our model-based experiments, it took concentration levels of 1,120 to 1,680 ppm to reach the average temperatures back then in the Antarctic.”

There is still one big question to be answered: If Antarctica used to be so warm, what caused it to dramatically cool, asks CBS News, allowing the formation of ice sheets? According to co-author and AWI climate modeler Dr. Gerrit Lohmann, in all of their climate simulations, researchers were “unable to find a satisfactory answer.”

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Rangers' Panarin, others donate N95 masks to hospitals – National Post

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New York Rangers forward Artemi Panarin provided quite the assist by aiding frontline health care workers in the battle against the coronavirus.

Panarin purchased and arranged the delivery of 1,500 N95 masks to Hospital for Special Surgery in New York.

“We are so grateful for Artemi Panarin’s incredibly generous gift of N95 masks to HSS,” said Dr. Bryan Kelly, the surgeon-in-chief at Hospital for Special Surgery, per NHL.com.

“Along with his teammates, Panarin also created a video thanking HSS for our commitment to helping NYC during this pandemic. On behalf of every clinical staff member at HSS, we would like to offer our heartfelt thanks to Panarin for his generosity during this time. Additionally, we’d like to thank Jim Ramsay, head athletic trainer for the Rangers, for his help coordinating their efforts.”

The masks were delivered on Friday.

Panarin is not alone, as Florida Panthers goaltender Sergei Bobrovsky and New York Islanders netminder Semyon Varlamov also purchased and arranged delivery of the N95 masks to hospitals in their respective markets.

Per NHL.com, Bobrovsky reportedly donated thousands of masks to multiple hospitals in the area of Fort Lauderdale, Fla.

Varlamov joined his teammates in donating 3,000 masks to Northwell Health system on Long Island.

“A heartfelt thanks to the @NYIslanders for supporting our Northwell Health #healthcareheroes with your delivery of N95 masks this week!” Northwell Health Foundation tweeted from the @GiveToNorthwell account.

N95 masks are in demand among medical providers because they help prevent a person from inhaling small, airborne infectious particles — a primary means of transmitting the coronavirus.

As of Sunday morning, more than 1.2 million people around the world had been diagnosed with the disease, with more than 67,000 fatalities, according to Johns Hopkins University.

–Field Level Media

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Earth's crust is shaking less as people stay home – MENAFN.COM

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(MENAFN – IANS)

London, April 5 (IANS) The COVID-19 lockdowns globally have not only made air breathable or rivers clean but have also resulted in the way our Earth moves, as researchers now report a drop in seismic noise (the hum of vibrations in the planets crust) because transport networks, real estate and other human activities have been shut down.

According an article in the journal Nature, efforts to curb the spread of coronavirus mean that the planet itself is moving a little less, which could “allow detectors to spot smaller earthquakes and boost efforts to monitor volcanic activity and other seismic events”.

Vibrations caused by moving vehicles and industrial machinery produce background noise, which reduces seismologists’ ability to detect other signals occurring at the same frequency.

“A noise reduction of this magnitude is usually only experienced briefly around Christmas,” said Thomas Lecocq, a seismologist with the Royal Observatory of Belgium in Brussels which has observed the drop in seismic noise.

Data from a seismometer at the observatory show that measures to curb the spread of COVID-19 in Brussels caused human-induced seismic noise to fall by about one-third.

In Belgium, scientists report at least a 30 per cent reduction in that amount of ambient human noise since lockdown began there.

The current drop has boosted the sensitivity of the observatory’s equipment, improving its ability to detect waves in the same high frequency range as the noise, said the Nature article.

However, not all seismic monitoring stations will see an effect as pronounced as the one observed in Brussels.

According to Emily Wolin, a geologist at the US Geological Survey in Albuquerque, New Mexico, many stations are purposefully located in remote areas to avoid human noise.

“These should see a smaller decrease, or no change at all, in the level of high-frequency noise they record,” she was quoted as saying.

The fall in noise could also benefit seismologists who use naturally occurring background vibrations, such as those from crashing ocean waves, to probe Earth’s crust.

A fall in human-induced noise could boost the sensitivity of detectors to natural waves at similar frequencies

“There’s a big chance indeed it could lead to better measurements,” said Lecocq.

The reduction in seismic activity, like reduction in air pollution, also show that people are adhering to social distancing guidelines.

“From the seismological point of view, we can motivate people to say, ‘OK look, people. You feel like you’re alone at home, but we can tell you that everyone is home. Everyone is doing the same. Everyone is respecting the rules,'” Lecocq told CNN.

–IANS

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