A species that lived about 520 million years ago and was thought to be the oldest known bryozoan is instead a type of colony-forming algae, a new study proposes.

Bryozoans are filter-feeding, tentacle-bearing animals that live in apartment complex–like colonies attached to rocks, shells or other surfaces on seafloors or lake bottoms. Trouble is, some other animals and algae inhabit the same sort of modular construction. While Protomelission gatehousei was first described in 1993, scientists didn’t categorize it as a bryozoan until 2021.

Now, analyses of fossils even better preserved than those described previously show that the species may not have been a bryozoan after all, says Martin Smith, a paleobiologist at Durham University in England.

Where previous fossils preserved only the skeletal framework of colonies, the new fossils, unearthed in southern China, include soft parts of the organism too, Smith says. And instead of the tentacles expected to have been found in an immaculately preserved bryozoan, the fossils have simple leaflike flanges typical of some types of algae, he and colleagues report March 8 in Nature.

If borne out, the new find means that the oldest unequivocal bryozoan fossils that are known are only about 480 million years old. That, Smith contends, makes bryozoans the only major group of animals not to have first appeared during the Cambrian Period, a burst of biological diversification that some scientists have referred to as “life’s Big Bang” and which ended about 488 million years ago (SN: 4/24/19).

As a result, the Cambrian was not, as previously thought, a unique interval of innovation in evolutionary history during which all the blueprints of animal life were mapped out, the researchers conclude.

“The question is, did evolution lose its ability to create new body plans?” Smith says. The team’s new find suggests not, he says.

Not everyone agrees that the new fossils aren’t bryozoans. The leaflike flanges described by Smith and his colleagues could just as easily be interpreted as body parts of individual animals in the bryozoan colony, says Paul Taylor, an invertebrate paleontologist at London’s Natural History Museum who wasn’t involved in the study.

Because the tentacles that bryozoans use to snatch prey from the water are soft tissue and typically don’t preserve well, their absence from the new fossils is not at all surprising, Taylor notes.

For Taylor, the new findings aren’t sufficient to dismiss P. gatehousei as a Cambrian bryozoan, but they do underline the inherent uncertainty in identifying fossils with simple body plans. More fossils preserving additional features, such as those that preserve the organism’s early growth stages, are needed to settle the question, he says.

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A gaggle of galaxies crackle with intricate detail in new images from the James Webb Space Telescope. JWST’s sharp infrared eyes are revealing how newborn stars shape their surroundings, giving hints to how stars and galaxies grow up together.

“We were just blown away,” says Janice Lee, an astronomer at the University of Arizona in Tucson. She and more than 100 astronomers reported on scientists’ first look at these galaxies with JWST in a special February issue of the Astrophysical Journal Letters.

Before JWST launched in December 2021, Lee and her colleagues selected 19 galaxies that, if observed with the telescope, they thought could reveal new details of the life cycles of stars (SN: 1/24/22). These galaxies are relatively close, within 65 million light-years of the Milky Way, and all have different types of spiral structures. The team had observed the galaxies with many observatories, but parts of the galaxies had always looked flat and featureless.

“With [JWST], we’re seeing structure down to the very smallest scales,” Lee says. “For the first time, we’re seeing the youngest sites of star formation in a lot of these galaxies.”

In the new images, the galaxies’ faces are pockmarked by dark voids amid glowing filaments of gas and dust. Comparisons to Hubble Space Telescope images reveal that these voids are bubbles carved out of the gas and dust by high-energy radiation from newborn stars in their centers.

Then, when the most massive of those stars reach the end of their life and explode, that gas gets pushed out even more. Some of the larger bubbles have smaller bubbles on their edges, which could indicate spots where the gas pushed by dying stars has started to build new stars.

Comparing these processes in different types of spiral galaxies will help astronomers understand how the galaxies’ shapes and properties influence the life cycles of their stars, and how the galaxies grow and change with their stellar denizens.

“We’ve only studied the first few [of the 19 selected] galaxies,” Lee says. “We need to study these things in the full sample to understand how the environment changes … how stars are born.”

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Fungi Q&A

Three types of fungi — Histoplasma, Coccidioides and Blastomyces — that cause serious lung infections were thought to be confined to certain regions of the United States. But now they are widespread in the country, Tina Hesman Saey reported in “Where fungal lung infections have spread” (SN: 1/14/23, p. 32).

The story prompted so many questions from readers about the symptoms, treatments and testing for these fungal infections that Saey answered them in a follow-up article online. An abridged version appears below.

How do you get infected?

People generally get infected by inhaling fungal spores. Human activities such as farming, gardening and construction can disturb the soil where these fungi live, stirring up spores. Bird droppings and bat guano can also be sources of Histoplasma. Sweeping dried droppings increases the risk that spores will get kicked into the air and inhaled.

When cleaning up bird and bat droppings, it’s best to first wet them with a hose. Wearing a mask can also help limit exposure.

What are the symptoms and treatments?

People with healthy immune systems may show no symptoms or may develop mild flulike symptoms, including fever, cough, fatigue, chills and body aches. Other symptoms may include chest pain or discomfort, weight loss, headache, muscle or joint pain, shortness of breath or night sweats.

People with coccidioidomycosis, also known as valley fever — the disease caused by Coccidioides — may also get a rash on their legs or upper body.

Symptoms can take time to appear. Those of histoplasmosis, the disease caused by Histoplasma, can develop between three and 17 days after exposure. Valley fever symptoms can appear between one and three weeks after exposure. For blastomycosis, the disease caused by Blastomyces, symptom onset can take anywhere from three weeks to three months.

Mild cases of all three infections usually clear up on their own in a few weeks to a few months. But some people may have lingering symptoms, especially if the infection becomes severe. Some people may develop severe or chronic pneumonia. And in a small number of people, the infections may spread to other parts of the body. For instance, Histoplasma tends to spread to the liver, spleen, bone marrow, adrenal glands and intestines. Blastomyces and Coccidioides often target joints. All three fungi can spread to the brain, where they may cause abscesses or meningitis — an inflammation of the membranes surrounding the brain and spinal cord.

Doctors can order blood or urine tests, chest X-rays or CT scans to help diagnose fungal infections. In some cases, doctors may need to test a small amount of body tissue or fluid from the spine or lungs.

Antifungal drugs and other medications can help treat infections and manage symptoms. If caught early, most people fully recover.

Who’s at risk?

Infections and severe disease from all three fungi occur more often in men than in women, but the reason is unclear. People who are pregnant, living with HIV/AIDS or have weakened immune systems for other reasons are at higher risk of severe disease. So are older people and those with diabetes.

Visit mycoses.org to assess your risk for fungal disease based on where you live.

Editor’s note

The study featured in “A newfound dinosaur had a flashy look” (SN: 1/16/21, p. 11) was withdrawn by Cretaceous Research in September 2021. In an email to Science News, journal publisher Lantice Brett stated that the withdrawal was due to ethical and legal concerns “regarding permissions for specimen export [which] remained unresolved nine months after [the study’s] initial publication.”

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What field of science could be more solid than geology? Rocks are visible, tangible. You can bang on them with a hammer, drill them, compress them, zap them with X-rays, ultraviolet light and radar, analyze their chemistry, extract their secrets.

The study of human behavior, by contrast, is the story of science’s struggle to identify the ineffable. Researchers have taken wildly different approaches to trying to figure out how people think and behave, from Sigmund Freud’s notion of the Oedipus complex to making behavioral science more “scientific” through efforts such as the Diagnostic and Statistical Manual of Mental Disorders and fMRI brain scans. Human life is messy, and no hammer tap will reveal the brain’s workings.

This issue of Science News articulates that duality in two features. Our cover story reports on the geology and chemistry of Mars, with NASA’s Perseverance rover scouting the Red Planet for rocks that could reveal signs of past life. In “Broken timelines,” social sciences writer Sujata Gupta investigates efforts to understand how life crises can cause some people to lose their sense of self and vision of the future. Helping people restore that vision, some researchers believe, could be a balm for PTSD and suicidal thinking.

As I read Gupta’s article, I could sense the scientists’ effort to quantify people’s experiences through definitions — self-continuity, autobiographical reasoning. These terms were new to me, and I found myself having to read closely to be sure I understood what the scientists meant. I took comfort in Gupta’s observation that philosophers have been wrestling with these questions for millennia. There are no easy answers.

When I turned to freelance writer Liz Kruesi’s account of the first two years of the Perseverance mission, I thought, “Ah, easy.” Find rocks, study rocks, confirm or reject hypotheses. NASA scientists directed the rover to the Jezero crater, the site of a dry lake bed that they presumed would be made of sedimentary rocks — the type of rock most likely to preserve evidence of ancient life. To their astonishment, the rover, affectionately known as Percy, instead found igneous rocks from past magmatic activity. The story was more complicated than most scientists thought.

Percy has since rolled on to a new location, the front of a dried-up delta, where it has found the sedimentary rocks the scientists were hoping for. The rover continues in its work as a robot geologist and astrobiologist, taking photos and collecting samples that are revealing the chemistry of the rocks. Bit by bit, that information will help scientists piece together the complex story of the planet’s history. Someday, they may even be able to answer the big question of whether life once thrived on Mars.

So maybe rocks and humans aren’t such different research subjects after all. Simple questions lead to complicated and contradictory data, with new discoveries challenging what we thought we knew to be true. As we learn, we rewrite the story of the past and get a clearer sense of what the future may hold. And so many questions remain to be answered.

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The 19th century landscape paintings hanging in London’s Tate Britain museum looked awfully familiar to climate physicist Anna Lea Albright. Artist Joseph Mallord William Turner’s signature way of shrouding his vistas in fog and smoke reminded Albright of her own research tracking air pollution.

“I started wondering if there was a connection,” says Albright, who had been visiting the museum on a day off from the Laboratory for Dynamical Meteorology in Paris. After all, Turner — a forerunner of the impressionist movement — was painting as Britain’s industrial revolution gathered steam, and a growing number of belching manufacturing plants earned London the nickname “The Big Smoke.”

Turner’s early works, such as his 1814 painting “Apullia in Search of Appullus,” were rendered in sharp details. Later works, like his celebrated 1844 painting “Rain, Steam and Speed — the Great Western Railway,” embraced a dreamier, fuzzier aesthetic.

Perhaps, Albright thought, this burgeoning painting style wasn’t a purely artistic phenomenon. Perhaps Turner and his successors painted exactly what they saw: their environs becoming more and more obscured by smokestack haze.

To find out how much realism there is in impressionism, Albright teamed up with Harvard University climatologist Peter Huybers, who’s an expert in reconstructing pollution before instruments existed to closely track air quality. Their analysis of nearly 130 paintings by Turner, Paris-based impressionist Claude Monet and several others tells a tale of two modernizing cities.

Low contrast and whiter hues are hallmarks of the impressionist style. They are also hallmarks of air pollution, which can affect how a distant scene looks to the naked eye. Tiny airborne particles, or aerosols, can absorb or scatter light. That makes the bright parts of objects appear dimmer while also shifting the entire scene’s color toward neutral white.

The artworks that Albright and Huybers investigated, which span from the late 1700s to the early 1900s, decrease in contrast as the 19th century progresses. That trend tracks with an increase in air pollution, estimated from historical records of coal sales, Albright and Huybers report in the Feb. 7 Proceedings of the National Academy of Sciences.

“Our results indicate that [19th century] paintings capture changes in the optical environment associated with increasingly polluted atmospheres during the industrial revolution,” the researchers write.

Albright and Huybers distinguished art from aerosol by first using a mathematical model to analyze the contrast and color of 60 paintings that Turner made between 1796 and 1850 as well as 38 Monet works from 1864 to 1901. They then compared the findings to sulfur dioxide emissions over the century, estimated from the trend in the annual amount of coal sold and burned in London and Paris. When sulfur dioxide reacts with molecules in the atmosphere, aerosols form.

As sulfur dioxide emissions increased over time, the amount of contrast in both Turner’s and Monet’s paintings decreased. However, paintings of Paris that Monet made from 1864 to 1872 have much higher contrast than Turner’s last paintings of London made two decades earlier.

The difference, Albright and Huybers say, can be attributed to the much slower start of the industrial revolution in France. Paris’ air pollution level around 1870 was about what London’s was when Turner started painting in the early 1800s. It confirms that the similar progression in their painting styles can’t be chalked up to coincidence, but is guided by air pollution, the pair conclude.

The researchers also analyzed the paintings’ visibility, or the distance at which an object can be clearly seen. Before 1830, the visibility in Turner’s paintings averaged about 25 kilometers, the team found. Paintings made after 1830 had an average visibility of about 10 kilometers. Paintings made by Monet in London around 1900, such as “Charing Cross Bridge,” have a visibility of less than five kilometers. That’s similar to estimates for modern-day megacities such as Delhi and Beijing, Albright and Huybers say.

To strengthen their argument, the researchers also analyzed 18 paintings from four other London- and Paris-based impressionists. Again, as outdoor air pollution increased over time, the contrast and visibility in the paintings decreased, the team found. What’s more, the decrease seen in French paintings lagged behind the decrease seen in British ones.

Overall, air pollution can explain about 61 percent of contrast differences between the paintings, the researchers calculate. In that respect, “different painters will paint in a similar way when the environment is similar,” Albright says. “But I don’t want to overstep and say: Oh, we can explain all of impressionism.”

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Pregnancy shrinks parts of the brain. That sounds bad. Throw in the forgetfulness and fogginess, or “momnesia,” that many moms report, and what’s left is the notion that for the brain, the transition to motherhood is a net loss.

“I see it on social media all the time,” says neuroscientist and therapist Jodi Pawluski of the University of Rennes in France. “Your brain shrunk. This is why [you] forget everything.”

But that’s just not true, Pawluski says. The perception that the maternal brain is dysfunctional has gone on long enough: It’s time to “start giving the maternal brain the credit it deserves,” Pawluski and her colleagues write February 6 in in JAMA Neurology.

Pregnancy does kick-start structural changes in the brain, including a loss of gray matter. But the loss isn’t automatically a bad thing — reductions can reflect a fine-tuning process that makes the brain more efficient (SN: 3/18/22).

During the transition to motherhood, the brain reorganizes its connections, strengthening those that are useful and letting go of those that aren’t, Pawluski says. This reorganization prepares the brain “to learn rapidly to keep a baby alive,” she says.

In a 2016 study, for example, researchers reported brain changes, including reductions, that appear to foster attachment to a new baby (SN: 12/19/16). Other work by this team found pregnancy-triggered decreases in the volume of the ventral striatum, a region involved in motivation and reward. Those reductions in mothers’ brains were associated with a heightened responsiveness toward their babies, the team reported in Psychoneuroendocrinology in 2020.

Still, many pregnant and postpartum women do report memory loss. Studies haven’t found large differences when testing memory for new moms compared with nonmothers, Pawluski says, but more research is needed to understand the mental load of parenthood — the impact of endless tasks and distractions.

A possible explanation for “momnesia” or “mommy brain” is that new mothers turn their attention toward baby and away from other things. Indeed, pregnant women, in contrast to never-pregnant women, demonstrated a boost in learning about baby-related objects as compared with adult-related items, researchers reported in Memory in 2022. Pregnant women also fared better with recalling relationships between objects and locations.

The changes in the maternal brain are akin to those seen during adolescence. A study of first-time mothers and female adolescents found that the reductions in volume in the maternal brain matched those seen in the teens, researchers reported in Human Brain Mapping in 2019. “We accept adolescence as being a time of transition and a lot of neuroplasticity,” or the brain’s ability to change, Pawluski says. The shift to motherhood is just as impactful on the brain, she says.

Giving the maternal brain its due for its incredible adaptations does not mean that caregiving is a skill exclusive to those who give birth. While hormones trigger brain modifications during pregnancy, nonbirthing parents’ brains change with the experience of having a newborn. After the birth of their first child, new fathers’ brains showed a reduction in gray matter, but childless men’s brains didn’t, researchers reported in Cerebral Cortex in 2022.

Changing misperceptions about the brain during the transition to motherhood “comes back to acknowledging the importance of caregiving,” Pawluski says, by all parents. “The ability for your brain to actually learn to keep a baby alive is a big deal.”

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An eye drop a day could keep myopia at bay — at least temporarily.

Using nightly eye drops with 0.05 percent atropine, a medication that relaxes the eye muscle responsible for focusing vision, may delay myopia onset in children, researchers report February 14 in JAMA.

Myopia, also called nearsightedness, is an irreversible condition in which the eyeball grows too long front to back, causing blurred distant vision. It typically begins in childhood, and the earlier it starts, the worse eye health can become later in life. Elongated eyes increase the risk for ocular complications including cataracts, glaucoma and macular degeneration.

The prevalence of myopia has risen rapidly over the last few decades. About one-fourth of the global population currently has the condition. It is expected to affect half of people worldwide by 2050.

Genetics plays a large role in the condition. A 2020 study found that myopia risk is more than 10 times as high in children of two highly myopic parents as in children of nonmyopic parents, says ophthalmologist Jason Yam of the Chinese University of Hong Kong.

But he and other scientists speculate that environmental factors such as less time outdoors and more intensive education are causing the recent boom (SN: 1/24/13). “It’s happening too quickly to be a purely genetic or inherited issue,” says optometrist Kathryn Saunders of Ulster University in Coleraine, Northern Ireland, who was not involved in the new study. 

Low-dose atropine eye drops are already used to slow myopia progression in several countries in Asia. Yam and colleagues wanted to see if the medication could also delay myopia onset.  

The team recruited nonmyopic children ages 4 through 9 who lived in Hong Kong. Each participant received nightly eye drops but was randomly assigned to receive drops with 0.05 percent atropine, 0.01 percent atropine or a placebo. Families and clinicians didn’t know which treatment group the children were in.

A total of 353 children used their assigned eye drops for two years. Only about 25 percent of children who took 0.05 percent atropine eye drops, roughly 30 kids, developed myopia in at least one eye, compared with about 50 percent of those who used 0.01 percent atropine or placebo eye drops, around 60 kids in each group. The percentages in each group were similar for eye elongation not severe enough to be considered myopia.

“It’s a great first step to encourage us to explore more,” Saunders says.

Scientists will need to conduct studies in more diverse populations and environments to reach generalizable conclusions since the trial took place in only Hong Kong. Eye color may also influence dosing, as lighter-pigmented eyes might be more susceptible to side effects, including sensitivity to light.

How atropine slows myopia onset and progression remains a mystery. The medication might improve blood circulation in the eye, Yam says, but that’s just one existing hypothesis.

The new study was too short to suggest that atropine eye drops can prevent myopia. But an ongoing follow-up period in which participants continue taking the medication through their teenage years — when eye length stabilizes — will help the team understand if atropine eye drops can ward off the condition altogether.

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A form of lightning with a knack for sparking wildfires may surge under climate change.

An analysis of satellite data suggests “hot lightning” — strikes that channel electrical charge for an extended period — may be more likely to set landscapes ablaze than more ephemeral flashes, researchers report February 10 in Nature Communications. Each 1 degree Celsius of warming could spur a 10 percent increase in the most incendiary of these Promethean bolts, boosting their flash rate to about four times per second by 2090 — up from nearly three times per second in 2011.

That’s dangerous, warns physicist Francisco Javier Pérez-Invernón of the Institute of Astrophysics of Andalusia in Granada, Spain. “There will be more risk of lightning-ignited wildfires.”

Among all the forces of nature, lightning sets off the most blazes. Flashes that touch down amid minimal or no rainfall — known as dry lightning — are especially effective fire starters. These bolts have initiated some of the most destructive wildfires in recent years, such as the 2020 blazes in California (SN: 12/21/20).

But more than parched circumstances can influence a blast’s ability to spark flames. Field observations and laboratory experiments have suggested the most enduring form of hot lightning — “long continuing current lightning”— may be especially combustible. These strikes channel current for more than 40 milliseconds. Some last longer than one-third of a second — the typical duration of a human eye blink.

“This type of lightning can transport a huge amount of electrical discharge from clouds to the ground or to vegetation,” Pérez-Invernón says. Hot lightning’s flair for fire is analogous to lighting a candle; the more time a wick or vegetation is exposed to incendiary energy, the easier it kindles.

Previous research has proposed lightning may surge under climate change (SN: 11/13/14). But it has remained less clear how hot lightning — and its ability to spark wildfires — might evolve.

Pérez-Invernón and his colleagues examined the relationship between hot lightning and U.S. wildfires, using lightning data collected by a weather satellite and wildfire data from 1992 to 2018.

Long continuing current lightning could have sparked up to 90 percent of the roughly 5,600 blazes encompassed in the analysis, the team found. Since less than 10 percent of all lightning strikes during the summer in the western United States have long continuing current, the relatively high ignition count led the researchers to infer that flashes of hot lightning were more prone to sparking fire than typical bolts.

The researchers also probed the repercussions of climate change. They ran computer simulations of the global activity of lightning during 2009 to 2011 and from 2090 to 2095, under a future scenario in which annual greenhouse gas emissions peak in 2080 and then decline.

The team found that in the later period, climate change may boost updraft within thunderstorms, causing hot lightning flashes to increase in frequency to about 4 strikes per second globally — about a 40 percent increase from 2011. Meanwhile, the rate of all cloud-to-ground strikes might increase to nearly 8 flashes per second, a 28 percent increase.

After accounting for changes in precipitation, humidity and temperature, the researchers predicted wildfire risk will significantly increase in Southeast Asia, South America, Africa and Australia, and risk will go up most dramatically in North America and Europe. However, risk may decrease in many polar regions, where rainfall is projected to increase while hot lightning rates remain constant.

It’s valuable to show that risk may evolve differently in different places, says Earth systems scientist Yang Chen of the University of California, Irvine, who was not involved in the study. But, he notes, the analysis uses sparse data from polar regions, so there is a lot of uncertainty. Harnessing additional data from ground-based lightning detectors and other data sources could help, he says. “That [region is] important, because a lot of carbon can be released from permafrost.”

Pérez-Invernón agrees more data will help improve projections of rates of lightning-induced wildfire, not just in the polar regions, but also in Africa, where blazes are common but fire reports are lacking.

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