Climate change wiped out nearly two thirds of the mammal species in Africa and the Arabian Peninsula in a mass extinction event 30 million years ago that researchers have only just learned about now.
According to a new study, published in the journal Communications Biology, the Earth’s climate dramatically shifted during the transition between the geological periods called the Eocene and Oligocene.
The Earth grew colder, ice sheets expanded, sea levels dropped, forests changed to grasslands, and carbon dioxide became scarce, the researchers said. In Asia and Europe, nearly two-thirds of the species known at that time went extinct.
Mammals in Africa, however, were thought to have been largely spared due to the continent’s mild climate and proximity to the equator.
As it turns out, that was not the case.
By analyzing a large collection of fossils housed at the Duke Lemur Center Division of Fossil Primates (DLCDFP) in Durham, N.C., researchers have been able to show that mammals in Africa and the Arabian Peninsula were just as affected by climate change as those in Asia and Europe.
To reach this conclusion, the team comprised of researchers from the U.S., England, and Egypt studied fossils from five mammal groups:
- A group of extinct carnivores called hyaenodonts;
- two rodent groups;
- a group of scaly-tail squirrels called anomalures;
- the hystricognaths group (which includes porcupines and naked mole rats)
- a group called strepsirrhines (lemurs and lorises); and
- humans’ ancestors, the anthropoids (apes and monkeys).
The researchers gathered data on hundreds of fossils from multiple sites in Africa in order to construct evolutionary trees for these five different groups and pinpoint when new lineages branched out and time-stamp each species’ first and last known appearance.
They discovered that all five mammal groups suffered huge losses around the period in question.
“It was a real reset button,” Dorien de Vries, the study’s lead author and a postdoctoral researcher at the University of Salford, said in a press release.
By reset, he means they were able to show how these mammal groups started popping up again in the fossil records a few million years after the mass extinction event; however, with one major caveat.
The fossil species that appeared in the Oligocene period were different from their earlier ancestors.
According to the study, the evidence for this was in the species’ teeth.
“We see a huge loss in tooth diversity, and then a recovery period with new dental shapes and new adaptations,” de Vries said.
The rodents and primates that emerged later had different teeth, which led the researchers to conclude they were new species that ate different things and had different habitats.
“Extinction is interesting in that way,” Matt Borths, curator of Duke University’s DLCDFP and co-author of the paper, said. “It kills things, but it also opens up new ecological opportunities for the lineages that survive into this new world.”
The researchers described this period of decline in diversity followed by a recovery as a sort of “evolutionary bottleneck,” in which most lineages went extinct and only a few survived.
Erik Seiffert, a professor and chair of the Department of Integrative Anatomical Sciences at the Keck School of Medicine of the University of Southern California and a senior co-author of the paper, said diversity in humans’ anthropoid ancestors was reduced to a single tooth type after the extinction event.
“There’s an interesting story about the role of that bottleneck in our own early evolutionary history,” Seiffert said.
“We came pretty close to never existing, if our monkey-like ancestors had gone extinct 30 million years ago. Luckily they didn’t.”
Guilt, grief and anxiety as young people fear for climate’s future
Overwhelmed, sad, guilty are some of the emotions young people say they feel when they think of Climate Change and their concerns world leaders will fail to tackle it.
Broadly referred to as climate anxiety, research has stacked up to measure its prevalence ahead of the U.N. talks in Glasgow, which begin at the end of the month to thrash out how to put the 2015 Paris Agreement on curbing climate change into effect.
One of the biggest studies to date, funded by Avaaz, an online campaign network, and led by Britain’s University of Bath, surveyed 10,000 young people aged 16-25 years in 10 countries. It published its results in September.
It found around three quarters of those surveyed considered the future frightening, while a lack of action by governments and industry left 45% experiencing climate anxiety and distress that affected their daily lives and functioning.
Elouise Mayall, an ecology student at Britain’s University of East Anglia and member of the UK Youth Climate Coalition, told Reuters she had felt guilty and overwhelmed.
“What I’d be left with is maybe the sense of shame, like, ‘how dare you still want lovely things when the world is ending and you don’t even know if you’re going to have a safe world to grow old in’.”
She spoke of conflicting emotions.
“You might have sadness, there might be fear, there might be a kind of overwhelm,” she said. “And maybe even sometimes a quite like wild optimism.”
Caroline Hickman, a psychotherapist and lecturer at the University of Bath and one of the co-authors of the research published in September, is working to help young people manage climate-related emotions.
“They’re growing up with the grief and the fear and the anxiety about the future,” she told Reuters.
“SENSE OF MEANING”
London-based psychiatrist Alastair Santhouse sees climate change, as well as COVID-19, as potentially adding to the burden, especially for those pre-disposed to anxiety .
For now, climate anxiety alone does not normally require psychiatric help. Painful as it is, it can be positive, provided it does not get out of control.
“Some anxiety about climate change is motivating. It’s just a question of how much anxiety is motivating and how much is unacceptable,” said Santhouse, author of a book that tackles how health services struggle to cope with complex mental issues.
“The worry is that as climate change sets in, there will be a more clear cut mental health impact,” he added.
Among some of the world’s communities that are already the most vulnerable, extreme weather events can also cause problems such as post traumatic stress disorder.
Leading climate campaigner Greta Thunberg, 18, has experienced severe climate anxiety.
“It’s a quite natural response, because, as you see, as the world is today, that no one seems to care about what’s happening, I think it’s only human to feel that way,” she said.
For now, however, she is hopeful because she is doing everything she possibly can.
“When you take action, you also get a sense of meaning that something is happening. If you want to get rid of that anxiety, you can take action against it,” she said.
(Reporting by Barbara Lewis; Editing by Alison Williams)
Rocket failure mars U.S. hypersonic weapon test as others succeed
The Pentagon ‘s hypersonic weapon programs suffered a setback on Thursday when a booster rocket carrying a hypersonic weapon failed, people briefed on the test result said.
The test was intended to validate aspects of one of the Pentagon’s hypersonic glide vehicles in development, two of the people said.
Hypersonic glide vehicles are launched from a rocket in the upper atmosphere before gliding to a target at speeds of more than five times the speed of sound, or about 3,853 miles (6,200 kilometers) per hour.
In a separate series of tests conducted on Wednesday, the U.S. Navy and Army tested hypersonic weapon component prototypes. That test successfully “demonstrated advanced hypersonic technologies, capabilities, and prototype systems in a realistic operating environment,” the Pentagon said in a statement.
The United States and its global rivals have quickened their pace to build hypersonic weapons – the next generation of arms that rob adversaries of reaction time and traditional defeat mechanisms.
U.S. President Joe Biden expressed concern on Wednesday about Chinese hypersonic missiles, days after a media report that Beijing had tested a nuclear-capable hypersonic glide weapon.
Glide bodies are different from their air-breathing hypersonic weapon cousins which use scramjet engine technology and the vehicle’s high speed to forcibly compress incoming air before combustion to enable sustained flight at hypersonic speeds. An air-breathing hypersonic weapon was successfully tested in September.
Companies such as Lockheed Martin and Raytheon Technologies are working to develop the hypersonic weapon capability for the United States.
(Reporting by Mike Stone and Idrees Ali in Washington; Editing by Sandra Maler)
Patagonian fossils show Jurassic dinosaur had the herd mentality | Saltwire – SaltWire Network
By Will Dunham
(Reuters) – A vast trove of fossils unearthed in Argentina’s southern Patagonia region is offering the oldest-known evidence that some dinosaurs thrived in a complex and well-organized herd structure, with adults caring for the young and sharing a communal nesting ground.
Scientists said on Thursday the fossils include more than 100 dinosaur eggs and the bones of about 80 juveniles and adults of a Jurassic Period plant-eating species called Mussaurus patagonicus, including 20 remarkably complete skeletons. The animals experienced a mass-death event, probably caused by a drought, and their bodies were subsequently buried by wind-blown dust, the researchers said.
“It is a pretty dramatic scene from 193 million years ago that was frozen in time,” said paleontologist Diego Pol of the Egidio Feruglio Paleontological Museum in Trelew, Argentina, who led the research published in the journal Scientific Reports.
Mussaurus, which grew to about 20 feet (6 meters) long and about 1.5 tons, possessed a long neck and tail, with a small head. It was bipedal as an adult but newborns were quadrupedal. Mussaurus lived early in the Jurassic, the second of three periods comprising the age of dinosaurs. It was a relatively large beast for its time – much bigger than contemporaneous meat-eating dinosaurs. Dinosaurs became true giants later in the Jurassic.
“The site is one of a kind,” Pol said. “It preserves a dinosaur nesting ground including delicate and tiny dinosaur skeletons as well as eggs with embryos inside. The specimens we have found showed that herd behavior was present in long-necked dinosaurs since their early history. These were social animals, and we think this may be an important factor to explain their success.”
The animals were found to have been grouped by age at the time of their deaths, with hatchlings and eggs in one area while skeletons of juveniles were clustered nearby. The eggs were arranged in layers within trenches. Adults were found alone or in pairs.
This phenomenon, called “age segregation,” signals a complex social structure, the researchers said, including adults that foraged for meals and cared for the young. The researchers suspect that members of the herd returned to the same spot during successive seasons to form breeding colonies.
“The young were staying with the adults at least until they reached adulthood. It could be that they stayed in the same herd after reaching adulthood, but we don’t have information to corroborate that hypothesis,” said paleontologist and study co-author Vincent Fernandez of the Natural History Museum in London.
Herd behavior also can protect young and vulnerable individuals from attack by predators.
“It’s a strategy for the survival of a species,” Fernandez said.
The oldest previous evidence for dinosaur herd behavior was from about 150 million years ago.
The nesting ground was situated on the dry margins of a lake featuring ferns and conifers in a warm but seasonal climate. The eggs are about the size of a chicken’s, and the skeleton of a hatchling fits in the palm of a human hand. The adults got as heavy as a hippo.
A scanning method called high-resolution X-ray computed tomography confirmed that the embryos inside the eggs indeed were of Mussaurus.
Mussaurus was a type of dinosaur called a sauropodomorph, which represented the first great success story among herbivorous dinosaurs. Sauropodomorphs were an evolutionary forerunner to a group called sauropods known for long necks and tails and four pillar-like legs.
The largest land animals in Earth’s history were the sauropod successors of sauropodomorphs, as exemplified by a later denizen of Patagonia called Argentinosaurus that reached perhaps 118 feet (36 meters) in length and upwards of 70 tons.
(Reporting by Will Dunham in Washington, Editing by Rosalba O’Brien)
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