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An Alaskan volcano could help scientists understand why ‘stealthy’ volcanoes erupt without warning

When volcanoes are preparing to erupt, scientists rely on typical signs to warn people living nearby: deformation of the ground and earthquakes, caused by underground chambers filling up with magma and volcanic gas. But some volcanoes, called “stealthy” volcanoes, don’t give obvious warning signs. Now scientists studying Veniaminof, Alaska, have developed a model which could explain and predict stealthy eruptions.

“Despite major advances in monitoring, some volcanoes erupt with little or no detectable precursors, significantly increasing the risk to nearby populations,” said Dr. Yuyu Li of the University of Illinois, lead author of the study in Frontiers in Earth Science.

“Some of these volcanoes are located near major air routes or close to communities: examples include Popocatépetl and Colima in Mexico, Merapi in Indonesia, Galeras in Colombia, and Stromboli in Italy.

“Our work helps explain how this happens, by identifying the key internal conditions—such as low magma supply and warm host rock—that make eruptions stealthy.”

Warning signs

Veniaminof is an ice-clad volcano in the Aleutian Arc of Alaska. It’s carefully monitored, but only two of its 13 eruptions since 1993 have been preceded by enough signs to alert observing scientists. In fact, a 2021 eruption wasn’t caught until three days after it had started.

“Veniaminof is a case study in how a volcano can appear quiet while still being primed to erupt,” said Li. “It is one of the most active volcanoes in Alaska. In recent decades, it has produced several VEI 3 eruptions—moderate-sized explosive events that can send ash up to 15 km high, disrupt air traffic, and pose regional hazards to nearby communities and infrastructure—often without clear warning signs.”

To understand Veniaminof better, the scientists used monitoring data over three summer seasons immediately before the 2018 stealthy eruption, which produced only ambiguous warning signs immediately before it happened.

They created a model of the volcano’s behavior in different conditions which would change the impact of a filling magma reservoir on the ground above: six potential volumes of magma reservoir, a range of magma flow rates and reservoir depths, and three shapes of reservoir. They then compared the models to the data to see which matched best, and which conditions produced eruptions, stealthy or otherwise.

Volcano by the numbers

They found that a high flow of magma into a chamber increases the deformation of the ground and the likelihood of an eruption. If magma is flowing quickly into a large chamber, an eruption may not occur, but if one does, the ground will deform enough to warn scientists first.

Similarly, a high flow of magma into a small chamber is likely to produce an eruption, but not a stealthy one. Stealthy eruptions become likely when a low flow of magma enters a relatively small chamber. Compared to observational data, the results suggest that Veniaminof has a small magma chamber and a low flow of magma.

The model also suggests that different conditions could produce different warning signs. Magma flowing into larger, flatter chambers may cause minimal earthquakes, while smaller, more elongated chambers may produce little deformation of the ground. But stealthy eruptions only happen when all the conditions are in place—the right magma flow and the right chamber size, shape, and depth.

However, when the scientists added temperature to their model, they found that if magma is consistently present over time, so that the rock of the chamber is warm, size and shape matter less. If the rock is warm, it’s less likely to fail in ways that cause detectable earthquakes or deformation of the ground when magma flows into the chamber, increasing the likelihood of a stealthy eruption.

What next?

“To mitigate the impact of these potential surprise eruptions, we need to integrate high-precision instruments like borehole tiltmeters and strainmeters and fiber optic sensing, as well as newer approaches such as infrasound and gas emission monitoring,” said Li. “Machine learning has also shown promise in detecting subtle changes in volcanic behavior, especially in earthquake signal picking.”

At Veniaminof, taking measures to improve the coverage of satellite monitoring and adding tiltmeters and strainmeters could improve the rate of detection. In the meantime, scientists now know which volcanoes they need to watch most closely: volcanoes with small, warm reservoirs and slow magma flows.

“Combining these models with real-time observations represents a promising direction for improving volcano forecasting,” said Li. “In the future, this approach can enable improved monitoring for these stealthy systems, ultimately leading to more effective responses to protect nearby communities.”

More information: Stealthy magma system behavior at Veniaminof Volcano, Alaska, Frontiers in Earth Science (2025). DOI: 10.3389/feart.2025.1535083

Journal information: Frontiers in Earth Science 

Provided by Frontiers 

Early visions of Mars: Meet the 19th-century astronomer who used science fiction to imagine the red planet

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Living in today’s age of ambitious robotic exploration of Mars, with an eventual human mission to the red planet likely to happen one day, it is hard to imagine a time when Mars was a mysterious and unreachable world. And yet, before the invention of the rocket, astronomers who wanted to explore Mars beyond what they could see through their telescopes had to use their imaginations.

As a space historian and author of the book “For the Love of Mars: A Human History of the Red Planet,” I’ve worked to understand how people in different times and places imagined Mars.

The second half of the 19th century was a particularly interesting time to imagine Mars. This was a period during which the red planet seemed to be ready to give up some of its mystery. Astronomers were learning more about Mars, but they still didn’t have enough information to know whether it hosted life, and if so, what kind.

With more powerful telescopes and new printing technologies, astronomers began applying the cartographic tools of geographers to create the first detailed maps of the planet’s surface, filling it in with continents and seas, and in some cases features that could have been produced by life. Because it was still difficult to see the actual surface features of Mars, these maps varied considerably.

During this period, one prominent scientist and popularizer brought together science and imagination to explore the possibilities that life on another world could hold.

Camille Flammarion

One imaginative thinker whose attention was drawn to Mars during this period was the Parisian astronomer Camille Flammarion. In 1892, Flammarion published “The Planet Mars,” which remains to this day a definitive history of Mars observation up through the 19th century. It summarized all the published literature about Mars since the time of Galileo in the 17th century. This work, he reported, required him to review 572 drawings of Mars.

Like many of his contemporaries, Flammarion concluded that Mars, an older world that had gone through the same evolutionary stages as Earth, must be a living world. Unlike his contemporaries, he insisted that Mars, while it might be the most Earth-like planet in our solar system, was distinctly its own world.

It was the differences that made Mars interesting to Flammarion, not the similarities. Any life found there would be evolutionarily adapted to its particular conditions—an idea that appealed to the author H.G. Wells when he imagined invading Martians in “The War of the Worlds.”

But Flammarion also admitted that it was difficult to pin down these differences, as “the distance is too great, our atmosphere is too dense, and our instruments are not perfect enough.” None of the maps he reviewed could be taken literally, he lamented, because everyone had seen and drawn Mars differently.

Given this uncertainty about what had actually been seen on Mars’ surface, Flammarion took an agnostic stance in “The Planet Mars” as to the specific nature of life on Mars.

He did, however, consider that if intelligent life did exist on Mars, it would be more ancient than human life on Earth. Logically, that life would be more perfect—akin to the peaceful, unified and technologically advanced civilization he predicted would come into being on Earth in the coming century.

“We can however hope,” he wrote, “that since the world of Mars is older than our own, its inhabitants may be wiser and more advanced than we are. Undoubtedly it is the spirit of peace which has animated this neighboring world.”

But as Flammarion informed his readers, “the Known is a tiny island in the midst of the ocean of the Unknown,” a point he often underscored in the more than 70 books he published in his lifetime. It was the “Unknown” that he found particularly tantalizing.

Historians often describe Flammarion more as a popularizer than a serious scientist, but this should not diminish his accomplishments. For Flammarion, science wasn’t a method or a body of established knowledge. It was the nascent core of a new philosophy waiting to be born. He took his popular writing very seriously and hoped it could turn people’s minds toward the heavens.

Imaginative novels

Without resolving the planet’s surface or somehow communicating with its inhabitants, it was premature to speculate about what forms of life might exist on Mars. And yet, Flammarion did speculate—not so much in his scientific work, but in a series of novels he wrote over the course of his career.

In these imaginative works, he was able to visit Mars and see its surface for himself. Unlike his contemporary, the science fiction author Jules Verne, who imagined a technologically facilitated journey to the moon, Flammarion preferred a type of spiritual journey.

Based on his belief that human souls after death can travel through space in a way that the living body cannot, Flammarion’s novels include dream journeys as well as the accounts of deceased friends or fictional characters.

In his novel “Urania” (1889), Flammarion’s soul visits Mars in a dream. Upon arrival, he encounters a deceased friend, George Spero, who has been reincarnated as a winged, luminous, six-limbed being.

“Organisms can no more be earthly on Mars than they could be aerial at the bottom of the sea,” Flammarion writes.

Later in the same novel, Spero’s soul visits Flammarion on Earth. He reveals that Martian civilization and science have progressed well beyond Earth, not only because Mars is an older world, but because the atmosphere is thinner and more suitable for astronomy.

Flammarion imagined that practicing and popularizing astronomy, along with the other sciences, had helped advance Martian society.

Flammarion’s imagined Martians lived intellectual lives untroubled by war, hunger and other earthly concerns. This was the life Flammarion wanted for his fellow Parisians, who had lived through the devastation of the Franco-Prussian war and suffered starvation and deprivation during the Siege of Paris and its aftermath.

Today, Flammarion’s Mars is a reminder that imagining a future on Mars is as much about understanding ourselves and our societal aspirations as it is about developing the technologies to take us there.

Flammarion’s popularization of science was his means of helping his fellow Earth-bound humans understand their place in the universe. They could one day join his imagined Martians, which weren’t meant to be taken any more literally than the maps of Mars he analyzed for “The Planet Mars.” His world was an example of what life could become under the right conditions.

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Two-million-year-old pitted teeth from our ancient relatives reveal secrets about human evolution

The enamel that forms the outer layer of our teeth might seem like an unlikely place to find clues about evolution. But it tells us more than you’d think about the relationships between our fossil ancestors and relatives.

In our new study, published in the Journal of Human Evolution, we highlight a different aspect of enamel. In fact, we highlight its absence.

Specifically, we show that tiny, shallow pits in fossil teeth may not be signs of malnutrition or disease. Instead, they may carry surprising evolutionary significance.

You might be wondering why this matters. Well, for people like me who try to figure out how humans evolved and how all our ancestors and relatives were related to each other, teeth are very important. And having a new marker to look out for on fossil teeth could give us a new tool to help fit together our family tree.

Uniform, circular and shallow

These pits were first identified in the South African species Paranthropus robustus, a close relative of our own genus Homo. They are highly consistent in shape and size: uniform, circular and shallow.

Initially, we thought the pits might be unique to P. robustus. But our latest research shows this kind of pitting also occurs in other Paranthropus species in eastern Africa. We even found it in some Australopithecus individuals, a genus that may have given rise to both Homo and Paranthropus.

The enamel pits have commonly been assumed to be defects resulting from stresses such as illness or malnutrition during childhood. However, their remarkable consistency across species, time and geography suggests these enamel pits may be something more interesting.

The pitting is subtle, regularly spaced, and often clustered in specific regions of the tooth crown. It appears without any other signs of damage or abnormality.

Two million years of evolution

We looked at fossil teeth from hominins (humans and our closest extinct relatives) from the Omo Valley in Ethiopia, where we can see traces of more than 2 million years of human evolution, as well as comparisons with sites in southern Africa (Drimolen, Swartkrans and Kromdraai).

The Omo collection includes teeth attributed to Paranthropus, Australopithecus and Homo, the three most recent and well-known hominin genera. This allowed us to track the telltale pitting across different branches of our evolutionary tree.

What we found was unexpected. The uniform pitting appears regularly in both eastern and southern Africa Paranthropus, and also in the earliest eastern African Australopithecus teeth dating back around 3 million years. But among southern Africa Australopithecus and our own genus, Homo, the uniform pitting was notably absent.

A defect … or just a trait?

If the uniform pitting was caused by stress or disease, we might expect it to correlate with tooth size and enamel thickness, and to affect both front and back teeth. But it doesn’t.

What’s more, stress-related defects typically form horizontal bands. They usually affect all teeth developing at the time of the stress, but this is not what we see with this pitting.

2-million-year-old pitted teeth from our ancient relatives reveal secrets about human evolution
The uniform, even nature of the pitting suggests a genetic origin rather than environmental factors such as malnutrition or disease. Credit: Towle et al, Journal of Human Evolution (2025). DOI: 10.1016/j.jhevol.2025.103703

We think this pitting probably has a developmental and genetic origin. It may have emerged as a byproduct of changes in how enamel was formed in these species. It might even have some unknown functional purpose.

In any case, we suggest these uniform, circular pits should be viewed as a trait rather than a defect.

A modern comparison

Further support for the idea of a genetic origin comes from comparisons with a rare condition in humans today called amelogenesis imperfecta, which affects enamel formation.

About one in 1,000 people today have amelogenesis imperfecta. By contrast, the uniform pitting we have seen appears in up to half of Paranthropus individuals.

Although it likely has a genetic basis, we argue that the even pitting is too common to be considered a harmful disorder. What’s more, it persisted at similar frequencies for millions of years.

A new evolutionary marker

If this uniform pitting really does have a genetic origin, we may be able to use it to trace evolutionary relationships.

We already use subtle tooth features such as enamel thickness, cusp shape, and wear patterns to help identify species. The uniform pitting may be an additional diagnostic tool.

For example, our findings support the idea that Paranthropus is a “monophyletic group,” meaning all its species descend from a (relatively) recent common ancestor, rather than evolving separately from different Australopithecus taxa.

And we did not find this pitting in the southern Africa species Australopithecus africanus, despite a large sample of more than 500 teeth. However, it does appear in the earliest Omo Australopithecus specimens.

So perhaps the pitting could also help pinpoint where Paranthropus branched off on its own evolutionary path.

An intriguing case

One especially intriguing case is Homo floresiensis, the so-called “hobbit” species from Indonesia. Based on published images, their teeth appear to show similar pitting.

If confirmed, this could suggest an evolutionary history more closely tied to earlier Australopithecus species than to Homo. However, H. floresiensis also shows potential skeletal and dental pathologies, so more research is needed before drawing such conclusions.

More research is also needed to fully understand the processes behind the uniform pitting before it can be used routinely in taxonomic work. But our research shows it is likely a heritable characteristic, one not found in any living primates studied to date, nor in our own genus Homo (rare cases of amelogenesis imperfecta aside).

As such, it offers an exciting new tool for exploring evolutionary relationships among fossil hominins.

More information: Ian Towle et al, Uniform, circular, and shallow enamel pitting in hominins: Prevalence, morphological associations, and potential taxonomic significance, Journal of Human Evolution (2025). DOI: 10.1016/j.jhevol.2025.103703

Journal information: Journal of Human Evolution 

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

These mysterious dark ‘streaks’ on Mars aren’t what scientists initially believed

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Mysterious dark streaks first observed on Mars in the 1970s are not what many believed they were.

Scientists now say the curious features that stretch for hundreds of meters down Martian slopes were likely signs of wind and dust activity, not water.

“A big focus of Mars research is understanding modern-day processes on Mars — including the possibility of liquid water on the surface,” Adomas Valantinas, a postdoctoral researcher at Brown University, said in a statement. “Our study reviewed these features but found no evidence of water. Our model favors dry formation processes.”

Valantinas and the University of Bern’s Valentin Bickel coauthored the research, which was recently published in the journal Nature Communications.

To reach these conclusions, the researchers used a machine learning algorithm to catalog as many of the odd streaks as they could, creating a first-of-its-kind global Martian map containing some 500,000 streaks from more than 86,000 high-resolution images from NASA’s Mars Reconnaissance Orbiter.

Then, they compared their map to databases and catalogs of other factors, including temperature, wind speed, hydration, and rock slide activity. They looked for any correlations over hundreds of thousands of cases.

The authors found that the ominous streaks that don’t last for decades, known as recurring slope lineae or RSLs, are not generally associated with factors that suggest a liquid or frost origin. Those factors might include a specific slope orientation, high surface temperature fluctuations, and high humidity. The features were more likely to form in places with above-average wind speed and dust deposition. That points to a dry origin of formation, and they seem to show up in the same locations during the warmest periods of the Martian year before mysteriously vanishing.

They concluded that the older slope streaks, which run down cliff faces and crater walls, most likely form when dust suddenly slides off slopes following seismic activity, winds, or even the shockwaves from meteoroid impacts. The streaks appear most often near recent impact craters, where shockwaves may shake the surface dust loose. The shorter-lived ones are typically found in places where dust devils or rockfalls are frequent.

The authors of the findings created a major database of the streaks. They compiled some 500,000
The authors of the findings created a major database of the streaks. They compiled some 500,000 (NASA)

“There were statistically significant correlations between new impact sites and the appearance of nearby slope streaks in certain regions, supporting this view,” NASA said.

Previously, some had interpreted those streaks as liquid flows. It’s possible that small amounts of water could mix with enough salt to create a flow on the frozen Martian surface, Brown University noted. The red planet was once more temperate, and there is water under the surface of Mars. Others believed they were triggered by the dry process. These results cast new doubt on slope streaks and RSLs as habitable environments.

“That’s the advantage of this big data approach,” Valantinas said. “It helps us to rule out some hypotheses from orbit before we send spacecraft to explore.”

First named pterosaur from Japan sheds light on ancient flying reptiles

A team of researchers from Japan, China, and Brazil have discovered a new species of pterosaur from the Late Cretaceous of Japan, marking the first time a pterosaur has been named based on body fossils found in the country.

The species, Nipponopterus mifunensis, was identified from a partial neck vertebra originally discovered in the 1990s in the Mifune Group geological formation in Kumamoto Prefecture, located on Japan’s southern island of Kyushu.

After a detailed reassessment using advanced CT scanning provided by Kumamoto University and subsequent phylogenetic analysis, the research team concluded that the specimen represents a new genus and species within the Azhdarchidae family—a group known for containing some of the largest flying animals that ever lived.

The study is published in the journal Cretaceous Research.

The fossil is now on public display at the Mifune Dinosaur Museum in Kumamoto Prefecture, offering visitors a rare glimpse into Japan’s ancient skies.

“This is a major step forward for Japanese paleontology,” said Dr. Naoki Ikegami from the Mifune Dinosaur Museum. “Until now, no pterosaur had been formally named from skeletal remains found in Japan. This discovery provides crucial new insight into the diversity and evolution of pterosaurs in East Asia.”

Interestingly, Nipponopterus may have had a wingspan approaching 3–3.5 meters and lived during the Turonian–Coniacian stages of the Late Cretaceous, making it one of the earliest known members of its lineage.

The newly identified sixth cervical vertebra (neck bone) of Nipponopterus mifunensis reveals a set of striking features not seen in any previously known species. Most notably, it has a prominent, elevated dorsal keel that runs along the back of the bone—extending not just over the epipophysis but across the entire postexapophyseal peduncle.

Additional distinctive traits include a long groove running along the underside (ventral sulcus), a subtriangular-shaped condyle, and unusually positioned postexapophyses that project outward to the sides.

These characteristics set Nipponopterus mifunensis apart from all other known azhdarchid pterosaurs. Phylogenetic analysis places it within the Quetzalcoatlinae subfamily, identifying it as a close relative of both the mysterious “Burkhant azhdarchid” from Mongolia and the giant Quetzalcoatlus of North America.

The study was the result of an international collaboration involving researchers from Shihezi University in China, the Zoology Museum at the University of São Paulo in Brazil, and a team in Japan from the Mifune Dinosaur Museum, Kumamoto University, and Hokkaido University.

Researchers worked closely together, combining expertise in fossil analysis, imaging technology, analytical modeling and evolutionary studies.

“It’s a beautiful example of how science transcends borders,” noted Professor Toshifumi Mukunoki from the Faculty of Advanced Science and Technology, Kumamoto University.

More information: Xuanyu Zhou et al, Reassessment of an azhdarchid pterosaur specimen from the Mifune Group, Upper Cretaceous of Japan, Cretaceous Research (2024). DOI: 10.1016/j.cretres.2024.106046

Journal information: Cretaceous Research 

Provided by Kumamoto University 

Lighting a new way to predict earthquakes: Laboratory model links fault contact area to earthquake occurrences

Researchers have developed a laboratory earthquake model that connects the microscopic real contact area between fault surfaces to the possibility of earthquake occurrences. Published in the Proceedings of the National Academy of Sciences, this breakthrough demonstrates the connection between microscopic friction and earthquakes, offering new insights into earthquake mechanics and potential prediction.

“We’ve essentially opened a window into the heart of earthquake mechanics,” said Sylvain Barbot, associate professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences and principal investigator of the study.

“By watching how the real contact area between fault surfaces evolves during the earthquake cycle, we can now explain both the slow buildup of stress in faults and the rapid rupture that follows. Down the road, this could lead to new approaches for monitoring and predicting earthquake nucleation at early stages.”

For decades, scientists have relied on empirical “rate-and-state” friction laws to model earthquakes—mathematical descriptions that work well but don’t explain the underlying physical mechanisms. “Our model reveals what’s actually happening at the fault interface during an earthquake cycle.”

Barbot says the discovery is a deceptively simple concept: “When two rough surfaces slide against each other, they only make contact at minuscule, isolated junctions covering a fraction of the total surface area.” This “real area of contact”—invisible to the eye but measurable through optical techniques—turns out to be the key state variable that controls earthquake behavior.

Laboratory earthquakes: Lighting earthquakes in real time

The study utilizes transparent acrylic materials that allowed the researchers to literally watch earthquake ruptures unfold in real time. Using high-speed cameras and optical measurements, the team tracked how LED light transmission changed as contact junctions formed, grew and were destroyed during laboratory earthquakes.

“We can literally watch the contact area evolve as ruptures propagate,” Barbot said. “During fast ruptures, we see approximately 30% of the contact area disappear in milliseconds—a dramatic weakening that drives the earthquake.”

The laboratory results revealed a previously hidden relationship: The empirical “state variable” used in standard earthquake models for decades represents the real area of contact between fault surfaces. This discovery provides the first physical interpretation of a mathematical concept that has been central to earthquake science since the 1970s.

From simulation to prediction

The researchers analyzed 26 different simulated earthquake scenarios and found that the relationship between rupture speed and fracture energy follows the predictions of linear elastic fracture mechanics. The team’s computer simulations successfully reproduced both slow and fast laboratory earthquakes, matching not only the rupture speeds and stress drops but also the amount of light transmitted across the fault interface during ruptures.

As contact areas change during the earthquake cycle, they affect multiple measurable properties including electrical conductivity, hydraulic permeability and seismic wave transmission. Since the real area of contact affects multiple physical properties of fault zones, continuous monitoring of these proxies during earthquake cycles could provide new insights into fault behavior.

The implications extend far beyond academic understanding and laboratory experiments. The research suggests that monitoring the physical state of fault contacts could provide new tools for earthquake short-term systems and potentially for reliable earthquake prediction using the electric conductivity of the fault.

“If we can monitor these properties continuously on natural faults, we might detect the early stages of earthquake nucleation,” Barbot explained. “This could lead to new approaches for monitoring earthquake nucleation at early stages, well before seismic waves are radiated.”

Looking ahead

The researchers plan to scale up their findings outside controlled laboratory conditions. Barbot explained that the study’s model provides the physical foundation for understanding how fault properties evolve during seismic cycles.

“Imagine a future where we can detect subtle changes in fault conditions before an earthquake strikes,” Barbot said. “That’s the long-term potential of this work.”

In addition to Barbot, Baoning Wu, formerly at USC and now at the University of California, San Diego, authored the study.

More information: Wu, Baoning, Evolution of the real area of contact during laboratory earthquakes, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2410496122

Journal information: Proceedings of the National Academy of Sciences 

Provided by University of Southern California 

Chile hit by major 6.7 magnitude earthquake

A 6.7 magnitude earthquake struck northern Chile on Friday, causing minor infrastructure damage and cutting power to more than 20,000 people.

The US Geological Survey reported the quake hit at 1.15pm local time at a depth of 47 miles. Its epicentre was located near the coast of the Atacama Desert.

While the quake was felt across several communities in the Atacama Desert region, initial reports confirmed no immediate casualties. Chile’s Hydrographic and Oceanographic Service said the earthquake’s characteristics did not meet the conditions necessary to generate a tsunami along the South American coast.

The quake was at a depth of 104 km (64.62 miles).

Reports suggest it was also felt in Argentina.

How herbivore communities remained remarkably resilient for 60 million years despite extinction and upheaval

From mastodons to ancient rhinos and giant deer, large herbivores have been shaping Earth’s landscapes for millions of years. A new study, published in Nature Communications, shows how these giants responded to dramatic environmental shifts—and how their ecosystems found ways to stay together, even as species disappeared.

An international team of scientists analyzed fossil records from over 3,000 large herbivores across 60 million years.

“We found that the large herbivore ecosystems stayed remarkably stable over long periods of time, even as species came and went,” said Fernando Blanco, leading author and a researcher at the University of Gothenburg at the time. “But twice in the last 60 million years, the environmental pressure was so great that the entire system underwent global reorganization.”

Two major global shifts

The first major change occurred around 21 million years ago, when shifting continents closed the ancient Tethys Sea and formed a land bridge between Africa and Eurasia. This new land corridor unleashed a wave of migrations that reshaped ecosystems across the globe.

Among the travelers were the ancestors of modern elephants, which had evolved in Africa and began to spread across Europe and Asia. But deer, pigs, rhinos, and many other large plant-eaters also moved into new territories, altering the ecological balance.

The second global shift came around 10 million years ago, as Earth’s climate became cooler and drier. Expanding grasslands and declining forests led to the rise of grazing species with tougher teeth and the gradual disappearance of many forest-dwelling herbivores. This marked the beginning of a long, steady decline in the functional diversity of these animals—the variety of ecological roles they played.

Two big events shaped the herbivores during 60 million years but their role remains
Illustration of the Global network of ecological roles among large herbivores, different species on different places and over time, but with the same ecosystem role. Credit: Fernando Blanco

Fewer species, same structure

Despite these losses, the researchers found that the overall ecological structure of large herbivore communities remained surprisingly stable. Even as many of the largest species, like mammoths and giant rhinos, went extinct in the last 129,000 years, the basic framework of roles within ecosystems endured.

“It’s like a football team changing players during a match but still keeping the same formation,” said Ignacio A. Lazagabaster, researcher at CENIEH in Spain and co-author of the study. “Different species came into play and the communities changed, but they fulfilled similar ecological roles, so the overall structure remained the same.”

Two big events shaped the herbivores during 60 million years but their role remains
Wildebeest (Connochaetes taurinus) in the Tanzanian savanna. Credit: Juan López Cantalapiedra

Third tipping point

This resilience has lasted for the past 4.5 million years, enduring ice ages and other environmental crises up to the present day. However, the researchers caution that the ongoing loss of biodiversity—accelerated by human activity—could eventually overwhelm the system.

“Our results show that ecosystems have an amazing capacity to adapt. But the rate of change is so much faster this time. There’s a limit. If we keep losing species and ecological roles, we may soon reach a third global tipping point, one that we’re helping to accelerate,” says Juan L. Cantalapiedra, researcher at MNCN in Spain and senior author of the study.

More information: Fernando Blanco et al, Two major ecological shifts shaped 60 million years of ungulate faunal evolution, Nature Communications (2025). DOI: 10.1038/s41467-025-59974-x

Journal information: Nature Communications 

Provided by University of Gothenburg 

Hundreds evacuated as Guatemalan volcano erupts

Guatemalan authorities said Thursday they were evacuating more than 500 people after Central America’s most active volcano spewed gas and ash.

Residents were moved to shelters from communities near the Fuego volcano, located 35 kilometers (22 miles) from the capital Guatemala City.

“We prefer to leave rather than mourn the death of everyone in the village later,” Celsa Perez, 25, told AFP.

The government suspended local school activities and closed a road linking the south of the country to the colonial city of Antigua, a UNESCO World Heritage Site, disaster coordination agency Conred reported.

There have been several such mass evacuations in recent years because Fuego erupted, including in March of this year.

In 2018, 215 people were killed and a similar number left missing when rivers of lava poured down the volcano’s slopes, devastating a village.

Evacuees remain at a shelter after fleeing their village affected by the eruption of the Fuego volcano
Evacuees remain at a shelter after fleeing their village affected by the eruption of the Fuego volcano.

© 2025 AFP

Wasp lookalikes from 33 million years ago fooled ancient birds too

New fossil shows that precise wasp mimicry in hoverflies evolved far earlier than previously thought—and wasn’t shaped by modern birds.

Děčín, Czech Republic—A newly discovered fossil from the Early Oligocene reveals that hoverflies were already mastering the art of deception 33 million years ago. The fossil, Spilomyia kvaceki, found in the Děčín-Bechlejovice site in the Czech Republic, exhibits a strikingly well-preserved coloration pattern that mimics social wasps with exceptional accuracy.

Given that all previously described fossil mimics displayed only inaccurate resemblance to their hymenopteran models, this specimen provides the first known evidence of accurate wasp mimicry. The species is named in honor of the world-renowned paleobotanist Zlatko Kvaček, who worked in the Faculty of Science, Charles University.

This discovery provides unprecedented insight into the evolution of Batesian mimicry, a survival strategy in which harmless species evolve to imitate more dangerous ones, such as stinging insects. While modern mimicry is typically shaped by passerine birds—the dominant avian insect predators in Europe today—this study published in Current Biology demonstrates that non-passerine birds, such as those from the Coraciimorphae and Apodiformes groups, likely drove the development of accurate mimicry millions of years earlier.

“The fossil‘s detail is extraordinary. It shows that the mimicry of wasps we see in living hoverflies was already fully formed when Europe was dominated by very different kinds of birds,” says the study’s lead researcher Klára Daňková from Faculty of Science at Charles University in Prague.

The study also notes the presence of fossilized Palaeovespa wasps—potential models for the mimic—in the same locality, further supporting the hypothesis of early ecological interactions between mimics and models.

This find not only extends the known history of mimicry in insects but also reshapes our understanding of predator-prey interactions in deep time.

More information: Klára Daňková et al, Highly accurate Batesian mimicry of wasps dates back to the Early Oligocene and was driven by non-passerine birds, Current Biology (2025). DOI: 10.1016/j.cub.2025.02.069

Journal information: Current Biology 

Provided by Charles University