Science

cross-posted from: https://lemmygrad.ml/post/11178913

cross-posted from: https://lemmygrad.ml/post/11178911

Archive link: https://archive.ph/6Iiag

Chinese researchers have unveiled a new rare earth alloy so cold and efficient it could upend decades of reliance on helium-3 and send shock waves through the global race for quantum computers or ultra-sensitive detectors.

A mini-fridge built with the alloy has achieved temperatures extremely close to absolute zero using no moving parts. And it comes at a time when the US Defence Advanced Research Projects Agency (DARPA) is actively hunting for exactly such a technology.

On January 27, DARPA issued an urgent call for proposals: develop a modular, helium-3-free cooling system for next-generation quantum and defence technologies.

Less than two weeks later, the Chinese scientists answered – with a paper published in Nature.

The alloy “has the potential for mass production. The joint team has recently successfully developed a pure metal refrigeration module based on this alloy material,” the Chinese Academy of Sciences (CAS) said on its website on February 13.

“This highly efficient cooling module could offer a stable, portable cooling source for quantum chips and support major space exploration projects with a self-reliant refrigeration system,” CAS added.

“It marks a ‘China solution’ that ends dependence on helium-3.”

In physics, the lowest possible temperature is 0 Kelvin, or minus 273.15 degrees Celsius (minus 459.67 degrees Fahrenheit), a state known as “absolute zero”.

As materials approach this temperature, they exhibit radically different properties: liquid helium loses friction, mercury becomes superconductive and much cutting-edge quantum research becomes possible.

Currently, achieving such extreme low temperature primarily relies on a technique called dilution refrigeration, which requires helium-3. This stable isotope of helium is an essential resource that China largely imports. Its main sources are linked to nuclear weapons programmes in the United States and Russia, as well as civilian nuclear power plants in Canada.

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According to a research paper published in the journal Nature on February 11, the team employed an entirely different solid-state cooling technique known as adiabatic demagnetisation refrigeration (ADR).

In simple terms, the process involves a magnetic alloy being first placed in an existing low-temperature environment. Applying a magnetic field forces the countless internal microscopic magnets to align uniformly, releasing heat that is carried away.

When the alloy is then isolated from the environment and the magnetic field is removed, the internal magnets return to a disordered state, a process that absorbs heat and further lowers the material’s own temperature.

A major hurdle in this process has been the poor thermal conductivity of traditional materials. While they could get cold themselves, they struggled to effectively cool the surrounding components.

The collaborative team from the Institute of Theoretical Physics and the Hefei Institutes of Physical Science under CAS, together with Shanghai Jiao Tong University, has discovered a new material, a rare earth compound called EuCo2Al9 (ECA). It possesses thermal conductivity similar to metal, allowing it to efficiently channel the cold outward.

“ADR using ECA has achieved a minimum temperature of 106 millikelvin, setting a new record for metallic materials. Also, at such extreme temperatures, its thermal conductivity is one to two orders of magnitude higher than traditional magnetic refrigeration materials, overcoming the key bottleneck of inefficiently extracting the cooling power,” according to the academy.

The ADR method, which eliminates the need for helium-3, is gaining traction in the academic world.

In 2024, Peking University built two “refrigerators” using this principle for quantum computing research, which have been operating stably for several months.

Lightweight portability is poised to be a key advantage of the ECA refrigeration module. This year’s Chinese government work report mentions the goal of “cultivating and developing the quantum technology industry”.

Currently, superconducting quantum computers require massive dilution refrigerators to cool their chips to sub-kelvin temperatures. In the future, a more portable refrigeration module like this could be instrumental in building smaller, more compact quantum computers.

cross-posted from: https://lemmygrad.ml/post/11138809

Archive link: https://archive.ph/59mVr (Links omitted)

Antimatter is matter’s equal and opposite. If the two meet, they annihilate each other, turning entirely into energy. This makes it incredibly difficult to store or move antimatter.

On 24 March, a team at CERN, the European particle-physics laboratory near Geneva, Switzerland, transported 92 antiprotons in a specially designed bottle that traps the particles using magnetic fields. The bottle travelled on the back of a truck, taking a 30-minute journey around the lab’s site.

The experiment’s ultimate goal is to take the antiparticles to a location free of experimental noise, where antiprotons can be studied with greater precision than is possible in the CERN ‘antimatter factory’ where they are created.

CERN is the only place in the world that produces usable quantities of antiprotons. Many staff members turned out with their mobile-phone cameras to capture the truck as it travelled more than 8 kilometres around the site, reaching a maximum speed of 42 kilometres per hour.

“It is something humanity has never done before, it is historic,” says team member Stefan Ulmer, a physicist at Heinrich Heine University Düsseldorf (HHU) in Germany. “We bought a lot of champagne, and we invited the entire antimatter community to celebrate with us today.”

Antimatter can be used to study other phenomena, such as the structure of radioactive nuclei, or researched itself to unravel some of the Universe’s deepest mysteries. Physicists who created the antimatter factory more than 30 years ago dreamed that someday it might be possible to transport the material, says Christian Smorra, a physicist at the HHU who led the project. “Now it’s finally possible.”

“This is a great technological achievement,” says Tara Shears, a physicist at the University of Liverpool, UK. Antimatter is the most fragile type of matter there is, so storing it, let alone driving it around CERN, is “a technological marvel”, she says.

“I love the idea of CERN becoming the Deliveroo [a food-delivery company] of antimatter,” she adds.

Antimatter Deliveroo

Antiparticles are like their ordinary counterparts, except with their charge and magnetic properties reversed. Although matter is abundant, antimatter occurs naturally only very rarely. No one knows why this disparity exists, when both should have been created in equal amounts during the Big Bang.

CERN makes antimatter by colliding beams of protons into a dense metal, then using electric and magnetic fields to slow and capture the antiprotons that emerge. Most particles are lost in the painstaking process.

To develop a portable trap for the particles in which they never touch the matter-containing sides, scientists had to power a superconducting magnet system and use cryogenics to cool it to a chilly −269 °C. The bottle had to be kept in a high vacuum to stop antimatter from meeting any stray matter particles and being annihilated on the way; all the kit had to withstand the forces of the journey in a truck. The team installed a detector, which meant they could check on the antiprotons from the driving seat.

A single gram of antimatter would cost trillions of dollars to make, and its annihilation would release as much energy as a nuclear bomb. But on the basis of CERN’s current rate of production, it would take ten times the age of the Universe to accumulate that much, says Ulmer.

The next phase for the project, known as BASE-STEP, will probably involve delivering the precious cargo to another building at CERN, where the team can practise decanting the antiprotons into another trap, says Smorra.

After that, the team plans to transport the antiprotons around 700 kilometres to Düsseldorf, where the HHU team will use a new experimental lab, now under construction, to study it in around 2029. To measure the mass of the antiproton with extreme precision, physicists must measure its activity in a magnetic field, but the antimatter factory is full of fluctuating magnetic noise. Moving to a new location could improve the precision of measurements by 10 to 1,000 times, says Ulmer.

“For the BASE collaboration, today is really the starting point for entirely new types of experiments,” he says.

“Antimatter’s behaviour is such a mystery that any new information would be really welcome to us,” says Shears. And differences between the behaviour of antimatter and matter “could help us to understand how and why our Universe evolved and looks the way it does”, she says.

“It’s one of the most fundamental mysteries in our subject, and I hope precise measurements on CERN antimatter samples can give us new clues,” she adds.

doi: https://doi.org/10.1038/d41586-026-00950-w

Scientists in Brazil described a new-to-science species of poison dart frog last year. It was first found among the leaves of wild banana plants on a research expedition to the Juruá River Basin in the western Amazon in 2023.

The frog, around the length of a paperclip (14–17 millimeters, or 0.5-0.7 inches), is reddish-brown and blue on top, bright blue with black spots underneath, and has copper-colored legs. It was named Ranitomeya aetherea, in reference to the word “ethereal.”

“We attribute this name to one’s feeling of enchantment and delicacy when encountering these frogs, as if they were from outside this world,” the study’s authors wrote in the species’ description.

The species has only been found at one site, where it lays its eggs in the small pools of water that collect inside plant leaves. This remote habitat is largely intact, with no immediate threats from deforestation or wildfires, creating a shield of protection from human-led activities.

This is in stark contrast to most other amphibian species, 40% of which are threatened with extinction. However, researchers stressed that biopiracy — the illegal collection and trade of rare species — and climate change are still threats.

The frog’s exact toxicity is unknown, but the whole Ranitomeya family is known to be poisonous, with toxins on their skin and bright colors to alert would-be predators.

“We know it’s poisonous to those that try to prey on it,” lead author Alexander Mônico, a researcher at the National Institute for Amazonian Research (INPA), told Mongabay. “But for us it’s fine, we’re able to handle them with our bare hands. We just need to be careful about any cuts.”

March 20 is World Frog Day. Frogs and toads have inhabited Earth for hundreds of millions of years, but 40% of amphibians species are now at risk of extinction, according to the latest conservation assessments.

Every year, roughly 150 new amphibian species are described. But many are immediately listed as threatened or endangered due to habitat loss, disease and climate change.

“Some species may not even get named before they go extinct,” biologist Zeeshan Mirza told Mongabay in December 2025.

Over the last year, Mongabay’s reporters have covered pressing threats facing frogs in all corners of the world. Here are a few.

Rare galaxy frogs threatened by photo tourism in India

Seven rare galaxy frogs (Melanobatrachus indicus) disappeared from southern India’s Western Ghats rainforest after a small group allegedly spent four hours handling and photographing the animals, an anonymous informant reported.

Researchers studying galaxy frogs, named for their resemblance to a night sky, found overturned logs and trampled vegetation at the site where the frogs had lived among rotting wood and stones.

“These beautiful yet rare frogs are unlike anything else on our tiny corner of the universe,” K.P. Rajkumar, a Zoological Society of London fellow, told Mongabay reporter Liz Kimbrough. “This sad event is a stark warning for the consequences of unregulated photography.”

Endangered mountain yellow-legged frog reintroduced again in California

Conservationists released 350 endangered mountain yellow-legged frogs (Rana muscosa) into Bluff Lake in Southern California earlier this year.

The species was once highly abundant in the region, but in 2023, there were fewer than 200 adults, even following several previous frog releases produced through captive breeding.

Non-native rainbow trout have decimated the species. Climate-driven wildfires and drought paired with a chytrid fungus outbreak have made their survival in the wild even more difficult.

“I think for most species, we’re really hoping for recovery, right? But in this case, we’re trying to prevent extinction,” Debra Shier of San Diego Zoo Wildlife Alliance told Mongabay contributor Sean Mowbray. “We have to try everything in the conservation toolbox.”

Three ‘unassuming’ brown frogs described in Peru

Three new-to-science frog species were described in the remote Cordillera de Huancabamba in the northwestern Peruvian Andes: Pristimantis chinguelas, P. nunezcortezi and P. yonke.

Scientists behind the discovery found the species during a series of night expeditions between 2021 and 2024. They said satellite imagery from the area already showed habitat loss from fire, agriculture and cattle ranching.

“They’re small and unassuming, but these frogs are powerful reminders of how much we still don’t know about the Andes,” lead author Germán Chávez of the Peruvian Institute of Herpetology told Mongabay.

Arvoreznha, Brazil — Meet the admirable red-belly toad — a tiny amphibian found nowhere else on Earth but a small forest patch in southern Brazil. Don’t let its size fool you.

In 2014, it made history by halting the construction of a hydroelectric dam that would have wiped out its only home.

With just over 1,000 individuals left in the wild, the species is listed as critically endangered. In addition to climate change, the little toad suffers from the advance of agriculture and the threat of wildlife trafficking.

But this tiny hero doesn’t shy away from a challenge. In 2024, catastrophic floods swept through southern Brazil, submerging entire landscapes — including the fragile habitat this little survivor depends on. Did it make it through? Or was this finally too much? Michelle Abadie, a researcher who has been studying the species for more than 15 years, went to the field to find out. Mongabay joined her on this mission to discover why even the smallest creatures can have an outsized impact.

Curious to see what happens next? Press play.

This tiny toad stopped a giant dam. Then historic floods hit.

The video is about 6’30” long. The post also contains a transcript which I haven’t copied here.

The tiny Amazon molly (Poecilia formosa) has always fascinated researchers because, according to the rules of evolution, it shouldn't have survived as a species, let alone thrive as a species for over 100,000 years. Using advanced genetic mapping and comparison techniques to track how the Amazon molly's DNA has changed over time, a new study set out to uncover the genetic secrets behind this apparent rebellion against evolutionary theory.

The molly undergoes asexual reproduction and gives live birth to its young, which are its clones, because the species is made up entirely of females—much like the all-female Amazonian warriors of Greek mythology, from whom it gets its name, not the Amazon Basin (where it doesn't live).

As per Muller's ratchet, a standard evolutionary theory, they should have gone extinct because clonal organisms accumulate harmful mutations over time due to a lack of genetic diversity.

The genetic evidence from this study, published in Nature, shows that the Amazon molly picks up mutations faster than its sexual relatives, yet somehow avoids the expected genetic decay—the secret behind this surprising act of resilience is gene conversion. This process purges harmful mutations by spotting damaged genes, "copying" a healthy version of the same gene from another part of the fish's own DNA, and "pasting" it over the faulty region to overwrite the mistake.

Accidental origin of the species

The Amazon molly didn't slowly evolve into a new species, it was the result of a 100,000-year-old accident. A long time ago, near Tampico, Mexico, a female Poecilia mexicana mated with a male Poecilia latipinna and created the hybrid—the Amazon molly. Every fish of that species alive today traces its lineage back to that single cross.

Unlike hybrid animals like a liger or mule, which are sterile and cannot reproduce, the Amazon molly is fully capable of reproducing asexually. Inside the mother's ovaries are specialized cells that undergo a modified version of meiosis—a type of cell division in sexually reproducing organisms—where the pairing up of chromosomes from two parents and swapping genetic information before dividing doesn't occur.

Instead, the mother produces eggs that already contain a full, double set of DNA that develops into new fish that are genetically identical to the mother. This form of cloning is called apomixis.

For a long time, scientists believed sexual reproduction was essential for long-term survival because it shuffles genes, removing harmful mutations and combining beneficial ones. The Amazon molly, however, gets the same advantages without ever mating.

Previous studies hinted at its high genetic diversity and signs of gene conversion, but detailed, haplotype-resolved genomic data were still missing.

Clues hidden in the genetic code

In this study, the researchers filled in this knowledge gap by creating a highly detailed and complete map of the entire genetic code for the Amazon molly and its two parent species using advanced long-read sequencing technology.

The researchers combined Hi-C and trio-binning to unravel the Amazon molly's genome. While Hi-C showed how DNA folds into chromosomes, trio-binning separated the two parental DNA sets, letting them study each lineage independently.

They found widespread presence of gene conversion, which supports two different pathways to reverse or correct unwanted genetic mutations: adaptive, or positive, selection, which promotes beneficial genetic mutations that enhance an organism's fitness, and second is purifying, or negative, selection, which helps reduce the presence of harmful genetic variations within a population.

The team also observed a higher rate of genetic repairs happening near DNA that carry crucial biological instructions, such as immunity or cell signaling.

Another fascinating detail revealed by the genome map was that out of the two sets of DNA present in the Amazon molly, one from each ancestral parent, is that the P. mexicana half of the fish's DNA is mutating and changing faster than the P. latipinna half, with changes mirroring those happening to the original species in the wild.

The study sheds light on long-debated questions about the evolutionary costs of asexual reproduction and establishes gene conversion as a powerful mechanism for effectively offsetting the negative effects. The findings give rise to a new question for future studies to explore: Do other long-lived asexual species avoid Muller's ratchet through the same process or is there something completely different at play?

A tropical insect has been found to change color from vivid hot pink to green within a fortnight, which scientists believe may mimic the young leaves of rainforest plants. The findings, published this week in the journal Ecology, focuses on Arota festae, a leaf-masquerading katydid also known as a "bush cricket," native to Panama, Colombia and Suriname.

When researchers spotted an adult female beneath a light at the Smithsonian Tropical Research Institute's field station on Barro Colorado Island, Panama, she was an unmistakable hot pink. Eleven days later, she was completely green.

Scientists from the University of St Andrews, University of Reading, the Smithsonian Tropical Research Institute, and University of Amsterdam, propose that the pink coloration evolved to mimic "delayed greening," a phenomenon in which newly emerged tropical leaves flush vivid shades of pink or red before maturing to green.

On Barro Colorado Island, around one-third of plant species show this trait all year, providing a reliable supply of pink leaves for a camouflaged insect to blend into.

Lead author Dr. Benito Wainwright, of the University of St Andrews, said, "Finding this individual was a genuine surprise. Because it was so rare, we kept it in natural conditions and found it changing color from hot pink to green.

"Rather than a bizarre genetic quirk, this may actually be a finely tuned survival strategy that tracks the life cycle of the rainforest leaves this insect is trying to resemble."

The team reared the individual in captivity for 30 days, photographing her daily. The hot pink faded to pastel after four days, and by day eleven, she was indistinguishable from the common green morph.

She survived to mate before dying naturally the following month.

Pink katydids have been documented in scientific literature since 1878 but were generally considered a rare, disadvantageous mutation. This appears to be the first recorded case of a katydid completing a full color shift within a single life stage.

Dr. Matt Greenwell, of the University of Reading, a co-author of the study, said, "Tropical forests are extraordinarily complex environments, and this discovery hints at just how precisely some animals have evolved to exploit them.

"You would think that a bright pink insect in a mostly green forest would stand out to predators like a worker in a high-vis jacket. The idea that an insect might gradually shift color to keep pace with the leaves it mimics shows how dynamic the rainforest can be, and is a remarkable example of camouflage in action."

Every animal carries a microscopic community of bacteria, fungi, and other microbes that play a critical role in health. These gut microbes help regulate the immune system, support digestion, and even influence how animals respond to stress. In birds, stress triggers the hormone corticosterone, which helps individuals cope with challenges. But when stress is prolonged or repeated, it can disrupt the balance of microbes in the gut, potentially affecting health in ways that aren't immediately visible.

Exploring stress and wild songbirds

While scientists have studied these stress–microbiome links extensively in mammals and domestic birds, little is known about how they operate in wild songbirds.

To fill this gap, Florida Atlantic University researchers and their collaborators studied free-living Northern cardinals (Cardinalis cardinalis), a common territorial songbird, to examine how everyday challenges affect gut microbial communities.

The team characterized the birds' microbiomes before and after an 11-day period during which the birds experienced one of three conditions: repeated simulated territorial interactions with other males; a brief holding period following routine capture; or no treatment at all.

Alongside the microbiome, researchers recorded levels of corticosterone, body condition, and beak coloration—a carotenoid-dependent trait that signals diet, health, and fitness.

The results, published in Scientific Reports, reveal that even relatively mild challenges can leave a clear mark on the gut microbiome. Birds exposed to social or environmental stressors showed changes in the composition of their gut bacteria, while the total number of microbial types remained stable.

Notably, birds briefly held after capture exhibited larger and more consistent shifts in microbial communities than those exposed only to simulated social interactions, highlighting how short departures from normal routines can have measurable biological effects.

Findings show that even subtle, everyday challenges can have profound effects on an animal's internal ecosystem. By revealing the hidden links between stress, microbial communities, and indicators of health, the study offers a new perspective on how wild animals navigate the demands of their environment—and how their tiny microbial passengers reflect those experiences.

"These microbial changes were not just abstract numbers. They were closely linked to visible signs of health," said Rindy Anderson, Ph.D., senior author and an associate professor in the Department of Biological Sciences within FAU's Charles E. Schmidt College of Science.

"Birds whose gut microbes shifted the most also showed changes in beak color, stress hormone levels, and body condition. Stress doesn't affect all birds in the same way. Instead, the microbiome may serve as a sensitive indicator of how individual animals are responding to their environment."

The study also uncovered links between specific types of bacteria and measures of health. For instance, males whose beaks became more orange—a signal often tied to condition and diet—also tended to have the largest shifts in their gut microbiome.

Birds exposed to brief captivity showed changes in bacterial groups associated with stress and potential pathogens, whereas increases in beneficial bacteria were associated with better physiological condition. Stress hormone patterns mirrored these microbial shifts: in challenged birds, changes in corticosterone levels were strongly correlated with changes in gut microbes, while untreated birds showed little connection.

"This study shows that the microbiome can act like a biological record of what an animal has experienced," said Morgan C. Slevin, Ph.D., first author and alumnus of the Integrative Biology Ph.D. Program in the FAU Department of Biological Sciences.

"By working with birds in their natural environment, we can see how different challenges—whether social interactions, environmental changes, or brief disruptions—translate into real physiological changes that matter for health and fitness.

"These microbial shifts give us a window into the hidden ways wild animals respond to the world around them, helping us understand their resilience and overall well-being in ways we couldn't see from behavior alone."

Why these findings matter for conservation

By combining microbiome analysis with physiological measures and visual indicators of condition, the study offers one of the first integrated looks at how stress, health, and microbial communities interact in a free-living songbird. The findings underscore the importance of studying animals in their natural habitats, where behaviors and environmental conditions can shape biology in ways that captivity studies may miss.

"The gut microbiome could serve as a sensitive measure of how wild animals respond to environmental changes, urbanization, or other stressors, with potential applications for conservation, wildlife rehabilitation, and understanding population health," said Anderson.

Study co-authors are Jennifer L. Houtz, Ph.D., an assistant professor of ecology and evolutionary biology at Allegheny College; and Maren N. Vitousek, Ph.D., an associate professor, Department of Ecology and Evolutionary Biology, Cornell University.

Three striking new species of rock-dwelling monitor lizards have been formally described from the savannas of northeastern Queensland, revealing a previously unrecognized evolutionary lineage. The discovery, led by researchers from The Australian National University (ANU), identified the rainbow rock monitor (Varanus iridis), the orange-headed rock monitor (Varanus umbra) and the yellow-headed rock monitor (Varanus phosphoros).

Together, the three species represent the first rock-adapted monitors formally recorded from the eastern Australian savannas. "Australia has a few rock monitors, but they're all known from much further west," co-lead author Dr. Stephen Zozaya from ANU said. "These are the first rock monitors known from the eastern Australian savannas."

The team initially believed the lizards represented a single, variable species. "We were blown away when the first genetic results came back. These three species are more distinct from one another than many monitor species that have been recognized for decades," Dr. Zozaya said.

Detailed genetic and morphological analyses confirmed the three populations are distinct species that have been evolving independently for millions of years. The findings reshape our understanding of diversity within one of the world's most iconic lizard groups—the same lineage that includes the Komodo dragon.

"All three species names refer to light in some way, to highlight the beautiful and distinct coloration of each of the new species. We feel very lucky to have had the chance to describe them," Dr. Zozaya said.

The lizards, newly described in the Zoological Journal of the Linnean Society, are closely tied to rocky outcrops scattered across the savanna landscape. Much remains unknown about their ecology, population sizes and exact distributions.

"These goannas are hard to find and hard to observe. More survey work—including records from nature enthusiasts—will be important for working out just how widespread these species really are," Dr. Zozaya said.

The discovery also underscores how much biodiversity remains undocumented in northern Australia. "These three species suggest there may still be a lot left to discover in northern Australia, even when it comes to large reptiles," Dr. Zozaya said.

Because monitor lizards attract significant attention from wildlife observers and reptile keepers, the species may face risk from habitat disturbance and illegal collection.

"Monitor lizards attract a lot of attention, from keen naturalists to reptile keepers. Unfortunately, some people searching for these animals are careless and damage cap-rock habitat—we've seen it firsthand," co-lead author and ANU Ph.D. researcher Wesley Read said. "Even slight rock displacement can make a shelter unusable. There's also a poaching risk, and we've already seen photos on social media showing some of these lizards in captivity.

"Most populations are in remote, rugged country, but I do worry about the most accessible areas. Time will tell."

The project brought together researchers, postgraduate students and experienced field naturalists. "We all fed off each other's excitement to get it done, and that made it really special," Read said.

The findings mark the first time rock-adapted monitors have been formally documented from the eastern Australian savannas, challenging long-held assumptions about where these specialized lizards occur and highlighting how much of Australia's reptile diversity remains to be uncovered.

Across the animal kingdom, sound is more than communication—it's a signal of survival and success. From birds and primates to insects, fish, and amphibians, animals broadcast acoustic "advertisements" to defend territory, attract mates, and reveal their physical condition. Because these calls can reflect traits such as body size, strength, or health, they play a powerful role in sexual selection and help shape how species compete and reproduce.

Parasites can influence these mating signals. Infections drain energy and trigger immune responses that weaken the body, altering traits tied to mating success, such as stamina and the quality of acoustic calls, sometimes disrupting how sounds are produced or perceived.

Adding to the complexity, some parasites infect hosts through predator-prey interactions. This means individuals that are larger or more effective at foraging—qualities often preferred by potential mates—may actually face a higher risk of infection. However, studies in amphibians have produced mixed results.

To explore this paradox, Florida Atlantic University researchers studied green treefrogs (Dryophytes cinereus) and oral frog tongueworm parasites (Halipegus occidualis) that live in the mouth and throat of frogs, to test whether food-web–transmitted parasites influence mating calls and female mate choice in a natural population.

During the breeding season, male green treefrogs gather in loud choruses around ponds, inflating their vocal sacs to produce repeated "honking" calls from nearby vegetation. Females use these calls to choose mates, typically favoring lower-frequency, faster, and sometimes longer calls—traits that often signal a larger or healthier male. Pulse patterns in the calls also help females recognize their own species.

Researchers recorded the calls of male green treefrogs in the wild and counted the number of tongueworm parasites in each frog's mouth. They then analyzed the recordings using audio software to measure features of the calls, such as frequency, length, and pulse structure. They aggregated calls into three infection categories: uninfected, moderately infected (five to eight adult worms), and heavily infected (more than nine adult worms).

To see how females responded, the team conducted two-choice playback experiments, broadcasting pairs of male calls and observing which one they approached.

Results of the study, published in the journal Current Zoology, suggest that choosy female green treefrogs may face a croak conundrum: the call traits they prefer—such as lower frequencies—are typically produced by larger males, which may also be more likely to carry parasites.

Tongueworm infections do influence the calls males use to attract mates, but not in the simple way scientists expected. Rather than just weakening signals, the parasites altered several call traits, creating a complex pattern that can change how females evaluate potential partners.

"Parasites don't always tell a simple story about health or weakness," said Sarah R. Goodnight, Ph.D., first author, a Ph.D. graduate of FAU Harbor Branch, and a postdoctoral fellow at the Smithsonian Environmental Research Center. "In this system, the frogs most successful at finding food may also be the ones most likely to pick up parasites. That means females are evaluating signals that can simultaneously advertise both strength and risk."

The findings challenge the long-standing Hamilton–Zuk hypothesis, which predicts that parasites reduce the quality of sexual signals and that females should prefer less-infected males. Instead, the pattern was more complex.

Larger male frogs—typically favored by females—also carried more tongueworm parasites, likely because males that eat more prey accumulate infections over time. Parasites subtly reshaped male calls: heavily infected frogs produced lower-frequency calls, a trait females usually prefer, but their calls were shorter, which can signal lower stamina.

Playback experiments revealed a similar pattern. Females avoided the most heavily infected males but often preferred males with moderate infections over uninfected ones, suggesting they weigh multiple signals at once—balancing traits linked to size and attractiveness against the risk of parasite infection.

Call duration appeared to play a particularly important role in this decision-making. Longer calls generally come from males with fewer parasites and greater energetic reserves, signaling vigor and lower infection risk. However, the relationship wasn't entirely straightforward: some moderately infected males produced longer calls than uninfected males, possibly because successful foragers accumulated both energy reserves and parasites.

"Mate choice is rarely based on a single trait," said Michael W. McCoy, Ph.D., co-author, associate director, FAU School of Environmental, Coastal, and Ocean Sustainability, and professor of quantitative ecology, Department of Biological Sciences, FAU Charles E. Schmidt College of Science and FAU Harbor Branch Oceanographic Institute.

"Our results show that parasites can reshape the information animals use when choosing partners by subtly changing multiple aspects of a male's call. Females may be responding to several signals at once, some linked to desirable traits like size and others hinting at infection. Understanding that complexity is critical for explaining how sexual selection actually works in natural populations."

The study reveals that parasites influence mate selection by altering multiple traits in male calls, creating a complex signal environment. Rather than just diminishing attractiveness, infections introduce nuanced cues that females must interpret, revealing how parasites subtly guide mating decisions and shape sexual selection in wild populations.

The study co-author is Ellen F. Titus with The Nature Conservancy.

The genus Gracixalus belongs to the family of Old World Tree Frogs and is geographically dispersed from Myanmar and western Thailand to Laos, Vietnam, and further to southern China. Despite the considerable amount of research on the species richness of Gracixalus, little is known about their vocalizations.

To remedy this problem, Gracixalus weii in southwest China has been investigated from a bioacoustic standpoint by researchers led by Caichun Peng of the Guizhou Leigongshan Forest Ecosystem Observation and Research Station. The research is published in the journal Herpetozoa.

The study reveals an acoustic convergence between frog advertisement calls and avian communication systems—specifically, the call of Gracixalus weii is remarkably similar to a bird-like chirp commonly performed by the Black-Breasted Thrush (Turdus dissimilis) of the same region.

Similarities like these have frequently led researchers to underestimate frog populations during field surveys because their chirps are easily mistaken for local bird songs.

To the human ear, vocalizations in the Leigongshan Nature Reserve often sound like a melodious bird song because both the Gracixalus weii and Black-Breasted Thrush use a similar pattern: a longer introductory note, followed by two shorter notes, and almost identical pitches. This phenomenon provides evidence to suggest that the evolution of acoustic symbols in amphibians could be influenced by broad ecological interactions, including with that of birds.

The history of observed similarities between frog and bird vocalizations can be traced further back; the acoustic convergence recorded in the Himalayan rapids in 1984 between frogs in the genus Nanorana and the bird Phylloscopius maginostrostris, for instance, underpins these recent findings.

Cases like these demonstrate that bioacoustic data adds value to species identification, particularly because advertisement calls serve as species-specific courtship signals that play an important role in evolutionary diversification.

For cryptic species that may appear identical, acoustic features also provide a reliable alternative to morphological or molecular diagnosis, offering clear evidence for taxonomic validity. Additionally, since many species are difficult to visually observe in dense habitats, such as frogs hiding within bamboo, relying on vocal signatures ensures that biodiversity is not misidentified during field surveys.

The authors argue that future research should focus on combining morphological, genetic, and bioacoustic evidence to better understand the species richness and cryptic diversity within the genus Gracixalus. A key priority is conducting experimental work, specifically playback or "replay experiments," to observe how Gracixalus weii and the Black-breasted Thrush (Turdus dissimilis) respond to one another's calls.

As such, the song of Gracixalus weii is a reminder that a familiar tune can be the perfect disguise for a species we are only just beginning to understand.

the frog news is hopping today

When a new species is discovered, it's tempting to imagine an adventure novel, said Chan Kin Onn of Michigan State University. "Most people have this image of an intrepid explorer braving an isolated mountain or some other remote place, and stumbling across a creature that no one has ever seen before," Chan said. Sure, that still happens occasionally. "But most of the time it's far less glamorous," he added.

Instead, the vast majority of new vertebrate species are "discovered" by revisiting known populations with new data or tools, and showing they were more distinct than previously thought.

Chan is a herpetologist, a scientist who specializes in studying amphibians and reptiles like frogs, turtles, lizards, and snakes. There are more than 9,000 species of amphibians on the planet, and each year roughly 100 to 200 are added to the list, he said.

Take a group of little brown frogs from Southeast Asia called the Bornean fanged frogs, so called because of tooth-like projections on their jaws. One of them, Limnonectes kuhlii, has been known to science since 1838. But in the last two decades, genetic analyses have found that what looks like one species might actually be as many as 18.

"Animals that look similar but are genetically distinct are called cryptic species," said Chan, who is also Curator of Vertebrate Collections and a core faculty member in MSU's Ecology, Evolution and Behavior program.

Due to advances in genetic sequencing, "a ton of cryptic species are being discovered left and right."

To see if, in fact, these frogs had been woefully undercounted, Chan and colleagues extracted DNA from specimens collected across the mountain rainforests of Malaysian Borneo and analyzed more than 13,000 genes across their genomes.

According to their work, published Jan. 14 in the journal Systematic Biology, the frogs do indeed fall into multiple genetic clusters. But only six or seven clusters could be classified as distinct species.

"It's not just one species. But it's not 18 species, either," Chan said.

The question is more than an academic hairsplitting exercise.

That's because the world's frogs are in trouble. A 2023 study of some 8,000 amphibian species worldwide revealed that two out of five amphibian species are threatened with extinction, making them the most endangered group of vertebrates on the planet.

On the one hand, if we don't know a species exists, we can't protect it, said Chan, who was a co-author on the 2023 study.

"There are so many species in the world that we still haven't discovered, and that could go extinct before we can give them a name," Chan said.

"But there's a flip side to that coin too," he added.

Overzealously splitting what was once considered one species into multiples can create problems for conservation biologists, making the geographic range of newly described cryptic species seem more restricted—and their situation more dire—than it really is.

"We cannot possibly conserve everything, so we have to triage and decide how to allocate limited resources toward what we think are the highest priorities," Chan said. "We could be putting names on things that shouldn't be prioritized."

The researchers also found a lot of interbreeding between these different frogs.

"We found a ton of gene flow going on," Chan said.

All the DNA moving back and forth can make for blurry dividing lines. As a result, some of the growing number of cryptic species may be more methodological artifact than biological reality, he added.

The fanged frogs in Borneo show that species don't evolve instantaneously. "It's not like all of a sudden, boom. It's more of a continuum," Chan said.

Fanged frogs are by no means the only group of animals whose numbers scientists may have miscalculated.

Over the past two decades, genetic studies of animals ranging from insects and fish to birds and mammals suggest there may be a staggering number of species hiding in plain sight.

Where once the total number of species on Earth was thought to be 8.7 million, more recent models accounting for cryptic species suggest the true number may be anywhere from 7 to 250 times that.

So where does the true number lie? "This study shows that there's a speciation 'gray zone' that can make it hard to draw the line," Chan said.

ⓘ This user is suspected of really liking frogs. Send newts (or something like that).

Smithsonian researchers in Panama have begun to reintroduce native golden frogs to the wild in special enclosures

The last known time that someone saw bright yellow frogs bespeckled with black dots in Panama’s wilderness was in 2009. These Panamanian golden frogs probably succumbed to a fungal disease called chytridiomycosis, which has decimated amphibian populations across the globe.

Now, researchers who have captive-bred the critically endangered golden frogs recently soft-released 100 of them into nature. The creatures stayed in special pens in late 2025 so that the scientists could assess how the deadly disease affects the animals—and how they might eventually adapt to it.

“This project was designed to see what would happen if we put these golden frogs back into a wild situation, just to kind of understand what are the disease dynamics, and how do these frogs regain their skin toxins,” Brian Gratwicke, a conservation biologist at the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI), tells Smithsonian magazine.

Chytridiomycosis is an infectious disease caused by the fungus Batrachochytrium dendrobatidis, or Bd, also called chytrid fungus. It’s thought to have reached southern Central America—where Panama is located—in the late 1980s. In 2019, researchers estimated that Bd had led to the extinction of 90 species worldwide as well as the decline of at least 491 others, and chytridiomycosis is often considered the most devastating wildlife disease on record.

Fungal spores can travel in water and even catch rides with other animals, including humans. Once they reach an amphibian, chytrid fungus can have devastating effects.

“It attacks the skin and kind of forms the ability to grow in and on the skin, and then causes, usually, the skin to fall off of the animal,” Jason Stajich, a microbiologist at the University of California, Riverside, who is not involved in the Panama project, tells Smithsonian magazine. “Because amphibians breathe through their skin, that can really impair them.”

Fun facts: Deceptive, deadly frog

• Despite their name, Panamanian golden frogs are actually toads.
• Research suggests that each frog has enough toxins in its skin to kill more than 1,000 mice.

Around two decades ago, experts at NZCBI and the Smithsonian Tropical Research Institute predicted the decline of golden frogs and other creatures in Panama based on how Bd was spreading. So, they partnered with the Cheyenne Mountain Zoo and Zoo New England to build the Panama Amphibian Rescue and Conservation Project (PARC) to protect animals at the highest risk of extinction from the fungal disease.

Gratwicke and his colleagues at PARC have been captive-breeding these amphibians for about 20 years. Now, the team has begun to release them back into nature to understand how to rewild these threatened species. In August 2025, the researchers put golden frogs in pens called mesocosms, which Gratwicke likens to outdoor patios.

“We put a big layer of leaf litter on the bottom that’s full of little insects and food so the frogs can forage,” he says. “It keeps the frogs inside where we can find them again, and it also keeps some of the predators out.”

The frogs spent 12 weeks inside these mesocosms, while researchers kept tabs on the creatures. During that time, about 70 percent of the frogs died from chytridiomycosis. Most of the surviving frogs were fully released into the wild afterwards.

Although the death rate was high, the data collected during this trial period is crucial to understanding how chytridiomycosis spreads and persists, and how amphibians might be able to adapt to chytrid fungus, Gratwicke says. “This experiment is probably the first experiment where we’ve actually been able to really get a full understanding of the disease dynamics of these animals.”

This might help researchers eventually place golden frogs in environments that are at adequate temperatures for the animals but too hot for the fungus. In recent research, for example, individuals of a frog species that lives in southeastern Australia seemed to have an easier time fending off chytrid fungus if they spent time in warm, sunny “saunas” than those in cooler temperatures.

And in some regions, amphibians whose numbers declined due to chytrid are beginning to bounce back. Tom Smith, a biologist at the University of California, Santa Barbara, has seen this happen with certain frogs in the Sierra Nevada mountains in California. “These populations have now been living with that pathogen for several generations across several decades, and we’re actually seeing adaptation and evolution to that in some of the populations,” he tells Smithsonian magazine.

Additionally, some frog species in the region do not seem to be susceptible to chytrid fungus, and scientists hope to use those species to “discover what the mechanism of tolerance and or resistance is to the disease,” says Smith, who is not involved in the Panama project.

For now, the team at PARC will continue to keep an eye on the Panamanian golden frogs to better understand fungal resilience in the creatures.

“I’ve been very pleased with the progress,” Gratwicke says. “It’s really important to actually make progress towards our ultimate goal, which is to create healthy, thriving populations of these animals to the wild. This experiment is one of the first steps towards achieving that.”

One of the links had another great photo of one:

Art by Dani Navarro, support human-made, scientifically accurate paleoart

https://nitter.net/playerDNG

Layperson article

https://www.sciencedaily.com/releases/2026/02/260222092251.htm

Primary source (paywalled)

https://www.science.org/doi/10.1126/science.adx5486

Excerpts from primary article

Editor’s summary Recent descriptions of and debates about the massive, fish-eating dinosaur Spinosaurus have brought this striking predator to the forefront of the dinosaur pantheon. Its huge size and distinctive morphology have stimulated much debate about the degree to which it lived an aquatic lifestyle. Sereno et al. describe a crested fossil Spinosaurus found in northern Africa as a new species. The researchers argue that this group of dinosaurs underwent three phases of evolution with increasing aquatic adaptations and existence in habitats around the Tethys Sea. —Sacha Vignieri

INTRODUCTION The fossils of Spinosaurus aegyptiacus, a giant sail-backed, fish-eating theropod dinosaur from northern Africa, have inspired competing lifestyle interpretations, either as a semiaquatic ambush predator stalking shorelines and shallows or a fully aquatic predator in pursuit of prey underwater. Its bones and teeth have been found only in coastal deposits near marine margins, a locale potentially consistent with either lifestyle interpretation.

RATIONALE In the central Sahara, a new fossiliferous area (Jenguebi) was discovered in beds equivalent in age [Farak Formation; Cenomanian ~95 million years ago (Mya)] to those yielding fossil remains of S. aegyptiacus. We describe from this area a new species, Spinosaurus mirabilis sp. nov., which is very similar to S. aegyptiacus in skeletal form but with a much taller, scimitar-shaped cranial crest. Two new sauropods were found in close association with the new spinosaurid buried in fluvial sediments indicative of an inland riparian habitat.

RESULTS S. mirabilis sp. nov. is distinguished by the low profile of its snout, a hypertrophied nasal-prefrontal crest, greater spacing of posterior maxillary teeth, and other features. Its features highlight the extraordinary specializations of both species of the genus Spinosaurus, including interdigitating upper and lower teeth. Principal component analysis of body proportions places spinosaurids between semiaquatic waders (e.g., herons) and aquatic divers (e.g., darters) distant from all other predatory dinosaurs. A time-calibrated phylogenetic analysis resolves three evolutionary phases: an initial Jurassic radiation when their distinctive elongate fish-snaring skull evolved and split into two distinctive designs, baryonychine and spinosaurine; an Early Cretaceous circum-Tethyan diversification when both reigned as dominant predators; and a final early Late Cretaceous phase when spinosaurines attained maximum body size as shallow water ambush specialists limited geographically to northern Africa and South America.

CONCLUSION The discovery of the tall-crested S. mirabilis sp. nov. in a riparian setting within an inland basin supports a lifestyle interpretation of a wading, shoreline predator with visual display an important aspect of its biology. At the end of the Cenomanian about 95 million years ago, an abrupt eustatic rise in sea level and the attendant climate change brought the spinosaurid radiation to an end.