Category: 7. Science

Fossils are invaluable archives of the past. They preserve details about living things from a few thousand to hundreds of millions of years ago.

Studying fossils can help us understand the evolution of species over time, and glimpse snapshots of past environments and climates. Fossils can also reveal the diets or migration patterns of long-gone species – including our own ancestors.

But when living things turn to rock, discerning those details is no easy feat. One common technique for studying fossils is micro-computerised tomography or micro-CT. It’s been used to find the earliest evidence of bone cancer in humans, to study brain imprints and inner ears in early hominins, and to study the teeth of the oldest human modern remains outside Africa, among many other examples.

However, our new study, published today in Radiocarbon, shows that despite being widely regarded as non-destructive, micro-CT may actually affect fossil preservation and erase some crucial information held inside.

Preserving precious specimens

Fossils are rare and fragile by nature. Scientists are constantly evaluating how to balance their impact on fossils with the need to study them.

When palaeontologists and palaeoanthropologists (who work on human fossils) analyse fossils, they want to minimise any potential damage. We want to preserve fossils for future generations as much as possible – and technology can be a huge help here.

Micro-CT works like the medical CT scans doctors use to peek inside the human body. However, it does so at a much smaller scale and at a greater resolution.

This is perfect for studying small objects such as fossils. With micro-CT, scientists can take high-resolution 3D images and access the inner structure of fossils without the need to cut them open.

These scans also allow for virtual copies of the fossils, which other scientists can then access from anywhere in the world. This significantly reduces the risk of damage, since the scanned fossils can safely remain in a museum collection, for example.

Micro-CT is popular and routinely used. The scientific community widely regards it as “non-destructive” because it doesn’t cause any visual damage – but it could still affect the fossil.

How does micro-CT imaging work?

Micro-CT scanning uses X-rays and computer software to produce high-resolution images and reconstruct the fossil specimens in detail. Typically, palaeontologists use commercial scanners for this, but more advanced investigations may use powerful X-ray beams generated at a synchrotron.

The X-rays go through the specimen and are captured by a detector on the other end. This allows for a very fine-grained understanding of the matter they’ve passed through – especially density, which then provides clues about the shape of the internal structures, the composition of the tissues, or any contamination.

The scan produces a succession of 2D images from all angles. Computer software is then used to “clean up” these high-resolution images and assemble them into a 3D shape – a virtual copy of the fossil and its inner structures.

But X-rays are not harmless

X-rays are a type of ionising radiation. This means they have a high level of energy and can break electrons away from atoms (this is called ionisation).

In living tissue, ionising radiation can damage cells and DNA, although the level of damage will depend on the duration and intensity of exposure. X-rays and CT scans used in medicine generally have a very low risk since the exposure of the human body is reduced as much as possible.

However, despite what we know about the impact of X-rays on living cells, the potential impact of X-rays on fossils through micro-CT imaging has never been deeply investigated.

What did our study find?

Using standard settings on a typical micro-CT scanner, we scanned several modern and fossil bones and teeth from animals. We also measured their collagen content before and after scanning.

Collagen is useful for many analytical purposes, such as finding out the age of the fossils using radiocarbon dating, or for stable isotope analysis – a method used to infer the diet of the extinct species, for example. The collagen content in fossils is usually much lower than in modern specimens because it slowly breaks down over time.

After comparing our measurements with unscanned samples taken from the same specimens, we found two things.

First, the radiocarbon age remained unchanged. In other words, micro-CT scanning doesn’t affect radiocarbon dating. That’s the good news.

The bad news is that we did observe a significant decrease in the amount of collagen present. In other words, the micro-CT scanned samples had about 35% less collagen than the samples before scanning.

This shows micro-CT imaging has a non-negligible impact on fossils that contain collagen traces. While this was to be expected, the impact hasn’t been experimentally confirmed before.

It’s possible some fossil samples won’t have enough collagen left after micro-CT scanning. This would make them unsuitable for a range of analytical techniques, including radiocarbon dating.

What now?

In a previous study, we showed micro-CT can artificially “age” fossils later dated with a method called electron spin resonance. It’s commonly used to date fossils older than 50,000 years – beyond what the radiocarbon method can discern.

This previous study and our new work show that micro-CT scanning may significantly and irreversibly change the fossil and the information it holds.

Despite causing no visible damage to the fossil, we argue that in this context the technique should no longer be regarded as non-destructive.

Micro-CT imaging is highly valuable in palaeontology and palaeoanthropology, no doubt about that. But our results suggest it should be used sparingly to minimise how much fossils are exposed to X-rays. There are guidelines scientists can use to minimise damage. Freely sharing data to avoid repeated scans of the same specimen will be helpful, too.

Most people assume an extinct volcano lies silent forever. Yet in Bolivia, the long‑quiet Uturuncu volcano keeps rumbling, forcing scientists to rethink what “dead” really means.

A new study mapped more than 1,700 tiny earthquakes to reveal why the mountain twitches instead of blows.

Professor Mike Kendall of the University of Oxford, who helped lead the project, calls the work a blueprint for decoding other restless peaks.

Where the heat hides

Beneath the Andes sits the Altiplano‑Puna Volcanic Complex, an underground magma lake roughly the size of Lake Superior, making it the largest known melt body in Earth’s upper crust.

That buried ocean feeds several peaks, including Uturuncu, keeping the so‑called zombie breathing.

Satellite surveys later showed the ground over this complex rising about 0.4 inches a year while ridges around it sag, forming the famous “sombrero” pattern.

The deformation hinted at magma or fluids on the move, but the detailed plumbing stayed invisible.

Extinct volcano rumblings

The project relied on seismic tomography, a scan that tracks earthquake waves as they cross different rock types. Slow zones revealed melted or fluid‑soaked rock, whereas fast lanes flagged cooler, solid crust.

“Our results show how linked geophysical and geological methods can be used to better understand volcanoes,” stated Kendall.

Analysts stitched those velocity patches into a three‑dimensional cutaway stretching nearly nine miles deep. 

The image traced narrow conduits climbing toward the summit, then widening into a lens of bubbly brine and semi‑molten rock about three miles below sea level.

That lens forms the top of a hydrothermal system, a pressurized mix of hot water, gas, and crystal mush.

Liquid, gas and false alarms

Pressure swings inside the shallow lens explain why the central cone inflates while surrounding valleys sink.

Computer models show that slight upticks in carbon dioxide or water vapor push the crust upward before venting and letting the land relax.

“Understanding the anatomy of the Uturuncu volcanic system was only possible thanks to the expertise within the research team,” added Professor Haijiang Zhang of the University of Science and Technology of China.

His comment underscores how petrophysics, chemistry, and fieldwork mesh to translate motion into meaning.

The group found no large pool of eruptible magma near the crater, cutting the odds of a sudden blast. Independent coverage affirms that Uturuncu remains restless yet harmless for now.

How the zombie myth began

Geologists label a volcano extinct when no eruptions have occurred for at least 10,000 years, so Uturuncu’s 250,000‑year hiatus easily qualifies.

Local Aymara communities, however, have long reported wisps of sulfurous steam that seemed to challenge the textbook definition.

Seismic antennas first recorded runaway swarms in the late 1990s, and satellite radar soon confirmed a dome of uplift nearly 40 miles wide.

Those two discoveries birthed the nickname “zombie,” suggesting a mountain that refuses to stay buried.

Global roundup of extinct volcanoes

Uturuncu is hardly unique. The United States Geological Survey counts about 1,350 potentially active volcanoes on land, though only 500 have erupted in recorded history.

“[The new toolkit could be deployed on] the more than 1,400 potentially active volcanoes and to the dozens of volcanoes like Uturuncu that aren’t considered active but that show signs of life,” noted co‑author Matthew Pritchard.

Dozens, like Bolivia’s zombie, puff gas or shake but have not erupted since before human memory. 

When a mountain labeled extinct suddenly quakes, officials face a communication dilemma. People hear “extinct” and assume zero risk, yet geoscientists know Earth ignores such labels.

The White Island tragedy in 2019 showed how even well‑monitored peaks can surprise tourists with steam‑driven blasts.

Though Uturuncu rises in a sparsely settled zone, mining projects and regional flights still depend on realistic alerts.

Climate links on the horizon

While Uturuncu lacks an ice cap, other dormant peaks may not stay quiet as the planet warms.

A report to the 2025 Goldschmidt Conference warned that retreating glaciers can lift pressure off magma chambers and spark new eruptions in formerly sleepy regions.

Changes in rainfall could play a similar role in the high Andes by flushing extra groundwater into the crust, altering pressure in the hydrothermal lens and nudging the volcano’s elastic shell.

Tomographic scans cost far less than drilling and can be repeated every few years, giving planners a real‑time gauge of subsurface shifts.

Coupled with satellite radar and gas sniffers, they let authorities move from folk wisdom to data when deciding evacuation thresholds.

Bolivian agencies have already installed new broadband seismometers around Uturuncu, and regional airports are integrating daily deformation bulletins into flight routing software.

Tracking extinct volcanoes

Researchers aim to extend their sensor net across the southern Altiplano to watch fluid pathways shift with rainfall and seasons. Time‑lapse tomography could track magma recharge years before it punches into the gas cap.

Meanwhile the “sombrero” bulge will keep lifting and settling, a geological chest rise mistaken by outsiders for resurrection.

For Kendall the marvel is not whether the mountain will reawaken but how finely researchers can now eavesdrop on its breathing.

Zombies make catchy folklore, yet Uturuncu shows that geology seldom follows the script. A volcano can seem to wake without ever intending to erupt because the fluids that once built it never stop moving.

The study is published in Proceedings of the National Academy of Sciences.

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Some of the most familiar atoms in the air above our heads appear to vanish when scientists audit Earth’s interior. Geochemists have spent decades tracing nitrogen’s trail yet always come up billions of tons short.

Earth’s rocky shell, the bulk silicate Earth (BSE), holds only one to five parts per million of nitrogen, a tally wildly below the cargo delivered by meteorites, say planetary physicists Shengxuan Huang and Taku Tsuchiya of Ehime University in a recent study.

Earth has a nitrogen gap

The nitrogen gap also skews the ratios between carbon, nitrogen, and argon, leaving Earth with a super‑chondritic chemical fingerprint that standard accretion models cannot match.

Solving the puzzle matters because those ratios control everything from mantle redox to atmospheric pressure.

Earlier studies blamed violent impacts that might have blasted nitrogen into space or suggested the planet formed from odd, nitrogen‑poor building blocks.

Neither idea fit every observation, especially the tight link between carbon and argon abundances.

Huang and colleagues wondered whether the answer lay not in the sky but in the metal heart of the planet.

Their hunch turned on how elements swap partners when molten rock and liquid iron separate during core‑mantle differentiation.

Supercomputers inside a magma ocean

To test it, the team recreated a primordial magma ocean, a globe‑spanning sea of lava that blanketed early Earth.

They used quantum‑level simulations to push virtual samples to 135 gigapascals and 9,000°F, conditions matching depths well below today’s mantle.

The code tracked each nitrogen atom as it chose between silicate melt and liquid iron, tallying a mathematical partition coefficient for every depth.

At 60 gigapascals (GPa), extreme pressure found deep inside the Earth, nitrogen was over 100 times more likely to bond with iron than with rock.

“Under the intense heat and pressure of a deep magma ocean, nitrogen became a ‘metal lover’,” said Huang.

The strong preference rose even higher at core‑forming depths, then leveled off, revealing a curved, not linear, relationship with pressure.

Pressure as matchmaker

The curvature solves a long‑standing lab conflict in which some high‑pressure experiments saw nitrogen favor metal while others did not. Those tests straddled the inflection point on the curve, so each captured a different slice of the trend.

Because the effect strengthens rapidly between 20 and 60 GPa, only a deep magma ocean can drain enough nitrogen into the core to match today’s mantle measurements.

Shallow oceans, by contrast, would leave too much nitrogen behind and pull Earth’s volatile ratios in the wrong direction.

Calculations show that a magma ocean reaching 60 GPa would lock roughly eighty percent of the planet’s nitrogen inside the core before the first crust ever solidified. The residual mantle concentration lands squarely in the observed one‑to‑five‑ppm window.

The simulations explain the atomic gymnastics behind the preference. Rising pressure breaks nitrogen’s bonds with itself and hydrogen, allowing single atoms to slip into gaps between iron atoms where they behave almost neutrally.

Inside silicate melt, however, high pressure forces nitrogen to bond with silicon as nitride ions, making it act like a charged outsider in an oxygen‑rich network. The contrasting chemical states tip the energetic scales decisively toward the core.

Adding sulfur or silicon to the metal cuts nitrogen’s affinity roughly in half, yet even an alloy doped with light elements still grabs the lion’s share. That robustness makes the core a dependable nitrogen vault throughout Earth history.

Carbon and argon tag along

Carbon shows subtler metal attraction. Laboratory experiments find metal‑silicate partition coefficients for carbon that swing from tens to above a thousand depending on temperature and oxygen fugacity.

Nitrogen’s coefficient, by contrast, rockets to several hundred under the same conditions.

Argon cares little for iron, preferring to stay either in silicate melt or in an atmosphere if one exists. This hierarchy (nitrogen > carbon > argon) naturally inflates Earth’s atmospheric 36Ar/N ratio while boosting its mantle C/N figure, without invoking exotic loss processes.

The model therefore reproduces two independent geochemical puzzles with one physical mechanism: deep core segregation in a thick magma ocean. 

Clues from mantle chemistry

Modern basalts erupting at mid‑ocean ridges still record the aftermath. Their nitrogen‑to‑argon ratios hover near chondritic values, a hint that the upper mantle has stayed nitrogen‑poor and argon‑moderate since the Hadean.

Diamonds mined from cratonic roots occasionally trap tiny blebs of iron nitride, mineralogical breadcrumbs that support a deep nitrogen transfer early in Earth’s life. Each inclusion whispers that some nitrogen did indeed ride metal downward.

Geochemists reached a similar conclusion back in 2015 by tallying global isotope budgets. Scientists have confirmed that the majority of the planetary budget of Nitrogen is in the solid Earth.

Earth’s nitrogen and exoplanets

Keeping just a sliver of nitrogen in the mantle turned out to be a sweet spot. Too much core sequestration would starve the atmosphere, while too little would upset carbon balance and maybe climate stability.

The work therefore tightens the range of interior conditions that can yield a clement surface, a useful guide as astronomers weigh exoplanet habitability.

Planets that form quickly and differentiate deeply may need later recycling to deliver enough nitrogen for life’s molecules.

Earth pulled off that tightrope act, but only just. Understanding how it happened helps scientists decode not only our own planet’s past but the prospects of rocky worlds scattered across the galaxy.

The study is published in Earth and Planetary Science Letters.

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WASHINGTON (AP) — Some dolphins in Australia have a special technique to flush fish from the seafloor. They hunt with a sponge on their beak, like a clown nose.

Using the sponge to protect from sharp rocks, the dolphins swim with their beaks covered, shoveling through rubble at the bottom of sandy channels and stirring up barred sandperch for a meal.

But this behavior — passed down through generations — is trickier than it looks, according to new research published Tuesday in the journal Royal Society Open Science.

Hunting with a sponge on their face interferes with bottlenose dolphins’ finely tuned sense of echolocation, of emitting sounds and listening for echoes to navigate.

“It has a muffling effect in the way that a mask might,” said co-author Ellen Rose Jacobs, a marine biologist at the University of Aarhus in Denmark. “Everything looks a little bit weird, but you can still learn how to compensate.”

Jacobs used an underwater microphone to confirm that the “sponging” dolphins in Shark Bay, Australia, were still using echolocation clicks to guide them. Then she modeled the extent of the sound wave distortion from the sponges.

For those wild dolphins that have mastered foraging with nose sponges, scientists say it’s a very efficient way to catch fish. The wild marine sponges vary from the size of a softball to a cantaloupe.

Sponge hunting is “like hunting when you’re blindfolded — you’ve got to be very good, very well-trained to pull it off,” said Mauricio Cantor, a marine biologist at Oregon State University, who was not involved in the study.

That difficulty may explain why it’s rare — with only about 5% of the dolphin population studied by the researchers in Shark Bay doing it. That’s about 30 dolphins total, said Jacobs.

“It takes them many years to learn this special hunting skill — not everybody sticks with it,” said marine ecologist Boris Worm at Dalhousie University in Canada, who was not involved in the study.

Dolphin calves usually spend around three or four years with their mothers, observing and learning crucial life skills.

The delicate art of sponge hunting is “only ever passed down from mother to offspring,” said co-author and Georgetown marine biologist Janet Mann.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

WASHINGTON (AP) — Some dolphins in Australia have a special technique to flush fish from the seafloor. They hunt with a sponge on their beak, like a clown nose.

Using the sponge to protect from sharp rocks, the dolphins swim with their beaks covered, shoveling through rubble at the bottom of sandy channels and stirring up barred sandperch for a meal.

But this behavior — passed down through generations — is trickier than it looks, according to new research published Tuesday in the journal Royal Society Open Science.

Hunting with a sponge on their face interferes with bottlenose dolphins’ finely tuned sense of echolocation, of emitting sounds and listening for echoes to navigate.

“It has a muffling effect in the way that a mask might,” said co-author Ellen Rose Jacobs, a marine biologist at the University of Aarhus in Denmark. “Everything looks a little bit weird, but you can still learn how to compensate.”

Jacobs used an underwater microphone to confirm that the “sponging” dolphins in Shark Bay, Australia, were still using echolocation clicks to guide them. Then she modeled the extent of the sound wave distortion from the sponges.

For those wild dolphins that have mastered foraging with nose sponges, scientists say it’s a very efficient way to catch fish. The wild marine sponges vary from the size of a softball to a cantaloupe.

Sponge hunting is “like hunting when you’re blindfolded — you’ve got to be very good, very well-trained to pull it off,” said Mauricio Cantor, a marine biologist at Oregon State University, who was not involved in the study.

That difficulty may explain why it’s rare — with only about 5% of the dolphin population studied by the researchers in Shark Bay doing it. That’s about 30 dolphins total, said Jacobs.

“It takes them many years to learn this special hunting skill — not everybody sticks with it,” said marine ecologist Boris Worm at Dalhousie University in Canada, who was not involved in the study.

Dolphin calves usually spend around three or four years with their mothers, observing and learning crucial life skills.

The delicate art of sponge hunting is “only ever passed down from mother to offspring,” said co-author and Georgetown marine biologist Janet Mann.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Paleontologists have identified a new genus and species of mole (family Talpidae) from a partial skeleton discovered at the Pliocene-aged site of Camp dels Ninots in Girona, Spain.

The newly-identified species, named Vulcanoscaptor ninoti, is a burrowing mole that lived in what is now Spain around 3.25 million years ago.

The animal’s fossilized skeleton was found in 2010 at the Camp dels Ninots site in Girona, Spain.

“This specimen preserves the mandible with a complete dentition, part of the torso, and several bones from both the forelimbs and hindlimbs, many of them still in anatomical connection,” said Dr. Marc Furió, a researcher at the Universitat Autònoma de Barcelona and the Institut Català de Paleontologia Miquel Crusafont (IPHES-CERCA), and his colleagues.

“The exceptional state of preservation is extremely rare in small mammals such as moles and makes this specimen one of the oldest and most complete ever found in Europe.”

“The fossil represents the most complete mole fossil known to date from the Pliocene of Europe and provides valuable insights into the evolutionary history of talpids.”

The fossil was partially embedded in a very compact sediment block and was extracted in its entirety during excavation.

To examine it in detail without damaging it, the paleontologists used high-resolution micro-computed tomography (microCT) scanning, which enabled a precise three-dimensional digital reconstruction of the skeleton.

“With the microCT, we were able to analyze extremely small and delicate structures — such as phalanges and teeth — that would have been nearly impossible to study otherwise,” said Dr. Adriana Linares, a researcher at the IPHES-CERCA.

“This allowed us to identify unique anatomical features and incorporate them into a robust phylogenetic analysis.”

The structure of Vulcanoscaptor ninoti’s forearm and front limbs revealed a high degree of adaptation to a subterranean lifestyle.

“The humerus is particularly robust, with prominent crests and extensive areas for muscle attachment, while the phalanges suggest strong digging capabilities,” Dr. Linares said.

“However, the fact that this individual was preserved in lacustrine sediments and in a lateral position raises the possibility that it may also have had some aquatic locomotion abilities.”

“We can’t confirm this with certainty yet, but there are modern moles that are powerful diggers and also excellent swimmers.”

According to the team, Vulcanoscaptor ninoti belonged to the Scalopini, a tribe of moles that today are found in North America and parts of Asia.

This discovery from Europe’s Pliocene site suggests a much more complex evolutionary and paleogeographic scenario than previously assumed.

“The description of Vulcanoscaptor ninoti confirms that the evolutionary history of moles has been far more dynamic than previously thought, involving possible intercontinental dispersals and an underappreciated anatomical diversity,” the authors said.

“It also highlights the importance of exceptional fossil sites in documenting species rarely preserved in the fossil record, such as small mammals.”

“Despite its clearly fossorial morphology, this mole is closely related to extant North American species of the genera Scapanus and Scalopus, which points to a far more intricate evolutionary history for these animals than we had imagined,” Dr. Furió added.

“Its presence in Europe suggests past transcontinental migrations of moles, challenging the assumption that they are mammals with low dispersal capacity.”

The team’s paper was published this month in the journal Scientific Reports.

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A. Linares-Martín et al. 2025. An unexpected Scalopini mole (Talpidae, Mammalia) from the Pliocene of Europe sheds light on the phylogeny of talpids. Sci Rep 15, 24928; doi: 10.1038/s41598-025-10396-1

In two new studies supported by FAPESP, researchers at the State University of Campinas (UNICAMP) in the state of São Paulo, Brazil, have shed light on how interactions between predators and prey influenced the extinction of saber-toothed tigers and the demise of the diverse antilocaprid species, which are now reduced to a single species: the American antelope.

In the first study, published in the Journal of Evolutionary Biology, the researchers used fossil databases, body size estimates, and data on climate variation in North America and Eurasia over the last 20 million years.

This allowed them to trace the evolutionary history and interactions that may have influenced the extinction of saber-toothed tigers. These felids are characterized by their elongated canines, suggesting that they were specialized predators of large animals.

“One of the hypotheses that’s received the most attention in the literature was that the end of saber-toothed tigers could be linked to the extinction of megafauna at the end of the Pleistocene, which occurred between 50,000 and 11,000 years ago. These large animals became extinct due to climate change and human actions, and as a result, the predators were left without their main prey,” says João Nascimento, the lead author of the studies, which were conducted during his PhD at the Institute of Biology (IB-UNICAMP) with a scholarship from FAPESP.

“However, we found that the process began millions of years earlier. Throughout the group’s history, there have been several different species of saber-toothed cats. Our study shows that the extinctions of some of them, throughout the group’s history, generally occurred at times when prey diversity was lower,” he explains.

In the other study, published in the journal Evolution, the authors observed a correlation in the opposite direction. The increase in predator diversity caused a decline in the species diversity of a group of herbivores known as antilocaprids.

Antilocaprids were once diverse animals in North America. Today, they are represented by a single species: the American bison (Antilocapra americana), one of the fastest herbivores in the world. One of the two subfamilies, Merycodontinae, became extinct about six million years ago. This coincided with the emergence of proboscids, the group of modern elephants that competed with the Merycodontinae for forest environments.

The other subfamily, Antilocaprinae, began to decline about six million years ago, which coincided with an increase in felid diversity. One example is the American cheetah (Miracinonyx), which, like the African cheetah, was adapted for high-speed pursuit.

Studies by other research groups suggest that predation by this species is one evolutionary explanation for the high speed of American antelopes. This study supports that hypothesis by showing that felid diversity may have impacted the past extinction of antilocaprids.

In a previous study, the researchers pointed to the gigantism of herbivores in the Iberian Peninsula as a factor that contributed to the extinction of predators 15 million years ago. This time, the studies cover much larger territories on a continental scale.

“The great contribution of this set of studies is precisely to present the idea that the interaction between predators and prey can have an effect on large evolutionary patterns. This had been debated for decades, but there was no really robust set of results to support this hypothesis,” says Mathias Pires, a professor at IB-UNICAMP who supervised the study.

Macroevolution

Both the current and previous studies were only possible due to the substantial amount of data on fossil records from North America and Eurasia, which includes information on body size and diet. These databases are available online for free and allow a variety of estimates to be made.

Armed with the data, the researchers traced the evolutionary history of several groups of large animals. This enabled them to estimate the probable timing of their emergence and extinction, as well as which species coexisted and interacted during the same period.

For example, saber-toothed cats appeared 12 million years ago in North America and 14 million years ago in Eurasia. At their peak, eight species coexisted. Their diversity remained stable until six million years ago, when it began to decline, eventually stabilizing at five species. They became extinct in the Holocene era, which began 11,700 years ago.

The period during which saber-toothed cats declined in diversity coincided with changes that made the climate more arid. This expansion of open environments increased the number of ruminant animals that feed on grasses. Meanwhile, leaf-eating animals lost the forests that provided their food and shelter.

“Our study did not find a direct relationship between this event and the reduction in saber-toothed cats, but these changes in the environment had an indirect impact on the extinctions of different saber-toothed species by reducing the availability of prey,” Pires says. 

One group that was adversely affected by these changes was the Merycodontinae. This subfamily of antilocaprids was folivorous and dependent on forests. Eventually, they became extinct. Meanwhile, the grazing antilocaprids – most of the Antilocaprinae at the time – prospered for longer, but they too declined with the increase in felid diversity.

“We’re showing how an increase in predators can reduce the availability of prey, which in turn reduces the abundance of predators, and how this can manifest on an evolutionary scale. It’s a warning about how we may be altering the future with the extinctions we’re causing now,” Pires concludes.

Using twin detectors of NSF’s Laser Interferometer Gravitational-wave Observatory (LIGO), astrophysicists with the LIGO-Virgo-KAGRA (LVK) Collaboration have detected the merger of two black holes with the highest combined mass ever observed. Discovered on November 23, 2023 and designated GW231123, the event produced a final black hole more than 225 times the mass of our Sun.

LIGO made history in 2015 when it made the first-ever direct detection of gravitational waves, ripples in space-time.

In that case, the waves emanated from a black hole merger that resulted in a final black hole 62 times the mass of our Sun.

The signal was detected jointly by the twin detectors of LIGO, one located in Livingston, Louisiana, and the other in Hanford, Washington.

Since then, the LIGO team has teamed up with partners at the Virgo detector in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan to form the LVK Collaboration.

These detectors have collectively observed more than 200 black hole mergers in their fourth run, and about 300 in total since the start of the first run in 2015.

Before now, the most massive black hole merger — produced by an event that took place in 2021 called GW190521 — had a total mass of 140 times that of the Sun.

In the GW231123 event, the 225-solar-mass black hole was created by the coalescence of black holes each approximately 100 and 140 times the mass of the Sun.

This puts it in a rare category of black holes called intermediate-mass black holes — heavier than those formed from stellar collapse, but much lighter than the supermassive black holes that lurk in the centers of galaxies.

In addition to their high masses, the merging black holes were also rapidly spinning.

“This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” said Dr. Mark Hannam, an astrophysicist at Cardiff University and a member of the LVK Collaboration.

“Black holes this massive are forbidden through standard stellar evolution models.”

“One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”

“This observation once again demonstrates how gravitational waves are uniquely revealing the fundamental and exotic nature of black holes throughout the Universe,” said Dr. Dave Reitze, executive director of LIGO at Caltech.

The researchers present the discovery of GW231123 this week at the 24th International Conference on General Relativity and Gravitation (GR24) and the 16th Edoardo Amaldi Conference on Gravitational Waves held jointly at the GR-Amaldi meeting in Glasgow, Scotland.

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LIGO-Virgo-KAGRA Collaboration. GW231123: The Most Massive Black Hole Binary Detected through Gravitational Waves. GR-Amaldi 2025

NASA scientists have found that cell-like compartments called vesicles, needed to form the precursors of living cells, could form in the lakes of Titan, Saturn’s largest moon.

These lakes and Titan’s seas are filled with liquid hydrocarbons like ethane and methane rather than water. And though we know water is a key ingredient of life on Earth, astrobiologists have theorized that Titan’s liquid hydrocarbons could allow the molecules needed for life to form, whether that life is similar to what we see on Earth or a very different form of life.

New research led by the University of Victoria (UVic) has illuminated a significant and previously unrecognized source of seismic hazard for the Yukon Territory of northwestern Canada.

The Tintina fault is a major geologic fault approximately 1,000 km long that trends northwestward across the entire territory. It has slipped laterally a total of 450 km in its lifetime but was previously believed to have been inactive for at least 40 million years. However, using new high-resolution topographic data collected from satellites, airplanes and drones, researchers have identified a 130-km-long segment of the fault near Dawson City where there is evidence of numerous large earthquakes in the much more recent geologic past (the Quaternary Period, 2.6 million years to present), indicating possible future earthquakes.

“Over the past couple of decades there have been a few small earthquakes of magnitude 3 to 4 detected along the Tintina fault, but nothing to suggest it is capable of large ruptures,” says Theron Finley, recent UVic PhD graduate and lead author of the recent article in Geophysical Research Letters. “The expanding availability of high-resolution data prompted us to re-examine the fault, looking for evidence of prehistoric earthquakes in the landscape.”

Currently, the understanding of earthquake rates and seismic hazard in much of Canada is based on a catalogue of earthquakes from oral Indigenous accounts, written historical records and modern seismic monitoring networks. Collectively, these records only cover the last couple hundred years. However, for many active faults, thousands of years can elapse between large ruptures.

When earthquakes are large and/or shallow, they often rupture the Earth’s surface and produce a linear feature in the landscape known as a fault scarp. These features, which can persist in the landscape for thousands of years, are typically tens to hundreds of kilometres long, but only a few metres wide and tall. They are difficult to detect in heavily forested regions like Canada, and require extremely high-resolution topographic data to identify.

The team, consisting of researchers from UVic, the Geological Survey of Canada and University of Alberta, used high resolution topographic data from the ArcticDEM dataset from satellite images, as well as from light detection and ranging (lidar) surveys conducted with airplanes and drones. They identified a series of fault scarps passing within 20 km of Dawson City.

Crucially, they observed that glacial landforms 2.6 million years in age are laterally offset across the fault scarp by 1000 m. Others, 132,000 years old, are laterally offset by 75 m. These findings confirm that the fault has slipped in multiple earthquakes throughout the Quaternary period, likely slipping several meters in each event. What’s more, landforms known to be 12,000 years old are not offset by the fault, indicating no large ruptures have occurred since that time. The fault continues to accumulate strain at an average rate of 0.2 to 0.8 millimetres per year, and therefore poses a future earthquake threat.

“We determined that future earthquakes on the Tintina fault could exceed magnitude 7.5,” says Finley. “Based on the data, we think that the fault may be at a relatively late stage of a seismic cycle, having accrued a slip deficit, or build-up of strain, of six metres in the last 12,000 years. If this were to be released, it would cause a significant earthquake.”

An earthquake of magnitude 7.5 or greater would cause severe shaking in Dawson City and could pose a threat to nearby highways and mining infrastructure. Compounding the hazard from seismic shaking, the region is prone to landslides, which could be seismically triggered. The Moosehide landslide immediately north of Dawson City and the newly discovered Sunnydale landslide directly across the Yukon River both show ongoing signs of instability.

Canada’s National Seismic Hazard Model (NSHM) includes the potential for large earthquakes in central Yukon Territory, but the Tintina fault is not currently recognized as a discrete seismogenic fault source. The recent findings by this team will ultimately be integrated into the NSHM, which informs seismic building codes and other engineering standards that protect human lives and critical infrastructure. The findings will also be shared with local governments and emergency managers to improve earthquake readiness in their communities.

This research occurred on the territory of the Tr’ondëk Hwëch’in and Na-Cho Nyäk Dun First Nations