We now have the most precise estimates for the strength of gravity yet.

Two experiments measuring the tiny gravitational attraction between objects in a lab have measured Newton’s gravitational constant, or Big G, with an uncertainty of only about 0.00116 percent. Until now, the smallest margin of uncertainty for any G measurement has been 0.00137 percent.

The new set of G values, reported in the Aug. 30 Nature, is not the final word on G. The two values disagree slightly, and they don’t explain why previous G-measuring experiments have produced such a wide spread of estimates (SN Online: 4/30/15). Still, researchers may be able to use the new values, along with other estimates of G, to discover why measurements for this key fundamental constant are so finicky — and perhaps pin down the strength of gravity once and for all.
The exact value of G, which relates mass and distance to the force of gravity in Newton’s law of universal gravitation, has eluded scientists for centuries. That’s because the gravitational attraction between a pair of objects in a lab experiment is extremely small and susceptible to the gravitational influence of other nearby objects, often leaving researchers with high uncertainty about their measurements.
The current accepted value for G, based on measurements from the last 40 years, is 6.67408 × 10−11 meters cubed per kilogram per square second. That figure is saddled with an uncertainty of 0.0047 percent, making it thousands of times more imprecise than other fundamental constants — unchanging, universal values such as the charge of an electron or the speed of light (SN: 11/12/16, p. 24). The cloud of uncertainty surrounding G limits how well researchers can determine the masses of celestial objects and the values of other constants that are based on G (SN: 4/23/11, p. 28).
Physicist Shan-Qing Yang of Huazhong University of Science and Technology in Wuhan, China, and colleagues measured G using two instruments called torsion pendulums. Each device contains a metal-coated silica plate suspended by a thin wire and surrounded by steel spheres. The gravitational attraction between the plate and the spheres causes the plate to rotate on the wire toward the spheres.

But the two torsion pendulums had slightly differently setups to accommodate two ways of measuring G. With one torsion pendulum, the researchers measured G by monitoring the twist of the wire as the plate angled itself toward the spheres. The other torsion pendulum was rigged so that the metal plate dangled from a turntable, which spun to prevent the wire from twisting. With that torsion pendulum, the researchers measured G by tracking the turntable’s rotation.

To make their measurements as precise as possible, the researchers corrected for a long list of tiny disturbances, from slight variations in the density of materials used to make the torsion pendulums to seismic vibrations from earthquakes across the globe. “It’s amazing how much work went into this,” says Stephan Schlamminger, a physicist at the National Institute of Standards and Technology in Gaithersburg, Md., whose commentary on the study appears in the same issue of Nature. Conducting such a painstaking set of experiments “is like a piece of art.”

These torsion pendulum experiments yielded G values of 6.674184 × 10−11 and 6.674484 × 10−11 meters cubed per kilogram per square second, both with an uncertainty of about 0.00116 percent.

This record precision is “a fantastic accomplishment,” says Clive Speake, a physicist at the University of Birmingham in England not involved in the work, but the true value of G “is still a mystery.” Repeating these and other past experiments to identify previously unknown sources of uncertainty, or designing new G–measuring techniques, may help reveal why estimates for this key fundamental constant continue to disagree, he says.

Now that heart recipients can realistically look forward to leaving the hospital and taking up a semblance of normal life, the question arises, what kind of semblance, and for how long? South Africa’s Dr. Christiaan Barnard, performer of the first heart transplant, has a sobering view…. “A transplanted heart will last only five years — if we’re lucky.” — Science News, September 14, 1968

Update
Barnard didn’t need to be so disheartening. Advances in drugs that suppress the immune system and keep blood pressure down have helped to pump up life expectancy after a heart transplant. Now, more than half of patients who receive a donated ticker are alive 10 years later. A 2015 study found 21 percent of recipients still alive 20 years post-transplant. In 2017, nearly 7,000 people across 46 countries got a new heart, according to the Global Observatory on Donation and Transplantation.

New images of gas churning inside an ancient starburst galaxy help explain why this galactic firecracker underwent such frenzied star formation.

Using the Atacama Large Millimeter/submillimeter Array, or ALMA, researchers have taken the most detailed views of the disk of star-forming gas that permeated the galaxy COSMOS-AzTEC-1, which dates back to when the universe was less than 2 billion years old. The telescope observations, reported online August 29 in Nature, reveal an enormous reservoir of molecular gas that was highly susceptible to collapsing and forging new stars.
COSMOS-AzTEC-1 and its starburst contemporaries have long puzzled astronomers, because these galaxies cranked out new stars about 1,000 times as fast as the Milky Way does. According to standard theories of cosmology, galaxies shouldn’t have grown up fast enough to be such prolific star-formers so soon after the Big Bang.

Inside a normal galaxy, the outward pressure of radiation from stars helps counteract the inward pull of gas’s gravity, which pumps the brakes on star formation. But in COSMOS-AzTEC-1, the gas’s gravity was so intense that it overpowered the feeble radiation pressure from stars, leading to runaway star formation. The new ALMA pictures unveil two especially large clouds of collapsing gas in the disk, which were major hubs of star formation.
“It’s like a giant fuel depot that built up right after the Big Bang … and we’re catching it right in the process of the whole thing lighting up,” says study coauthor Min Yun, an astronomer at the University of Massachusetts Amherst.

Yun and colleagues still don’t know how COSMOS-AzTEC-1 stocked up such a massive supply of star-forming material. But future observations of the galaxy and its ilk using ALMA or the James Webb Space Telescope, set to launch in 2021, may help clarify the origins of these ancient cosmic monsters (SN Online: 6/11/14).

One fine Hawaiian day in 2015, Geoff Zahn and Anthony Amend set off on an eight-hour hike. They climbed a jungle mountain on the island of Oahu, swatting mosquitoes and skirting wallows of wild pigs. The two headed to the site where a patch of critically endangered Phyllostegia kaalaensis had been planted a few months earlier. What they found was dispiriting.

“All the plants were gone,” recalls Zahn, then a postdoctoral fellow at the University of Hawaii at Manoa. The two ecologists found only the red flags placed at the site of each planting, plus a few dead stalks. “It was just like a graveyard,” Zahn says.

The plants, members of the mint family but without the menthol aroma, had most likely died of powdery mildew caused by Neoerysiphe galeopsidis. Today the white-flowered plants, native to Oahu, survive only in two government-managed greenhouses on the island. Why P. kaalaensis is nearly extinct is unclear, though both habitat loss and powdery mildew are potential explanations. The fuzzy fungal disease attacks the plants in greenhouses, and the researchers presume it has killed all the plants they’ve attempted to reintroduce to the wild.

Zahn had never encountered extinction (or near to it) so directly before. He returned home overwhelmed and determined to help the little mint.
Just like humans and other animals, plants have their own microbiomes, the bacteria, fungi and other microorganisms living on and in the plants. Some, like the mildew, attack; others are beneficial. A single leaf hosts millions of microbes, sometimes hundreds of different types. The ones living within the plant’s tissues are called endophytes. Plants acquire many of these microbes from the soil and air; some are passed from generation to generation through seeds.

The friendly microbes assist with growth and photosynthesis or help plants survive in the face of drought and other stressors. Some protect plants from disease or from plant-munching animals. Scientists like Zahn are investigating how these supportive communities might help endangered plants in the wild, like the mint on the mountain, or improve output of crops ranging from breadbasket wheat to tropical cacao.

Beyond the garden store
Certain microbial plant partners are well-known, and there are scores of microbial products already on the market. Gardeners, for instance, can spike their watering pails with microbes to encourage flowering and boost plant immunity. But “we know very little about how the products out there actually do work,” says Jeff Dangl, a geneticist at the University of North Carolina at Chapel Hill. “None of those garden supply store products have proven useful at large scale.”

Big farms can use microbial treatments. The main one applied broadly in large-scale agriculture helps roots collect nitrogen, Dangl says, which plants use to produce chlorophyll for photosynthesis.

Farmers may soon have many more microbial helpers to choose from. Scientists studying plant microbiomes have described numerous unfamiliar plant partners in recent decades. Those researchers say they’ve only scratched the surface of possibilities. Many start-up companies are researching and releasing novel microbial treatments. “The last five years have seen an explosion in this,” says Dangl, who cofounded AgBiome, which soon plans to market a bacterial treatment that combats fungal diseases. Agricultural giants like Bayer AG, which recently bought Monsanto, are also investing hundreds of millions of dollars in potential microbial treatments for plants.

The hope is that microbes can provide the next great revolution in agriculture — a revolution that’s sorely needed. With the human population predicted to skyrocket from today’s 7.6 billion to nearly 10 billion by 2050, our need for plant-based food, fibers and animal feed is expected to double.

“We’re going to need to increase yield,” says Posy Busby, an ecologist at Oregon State University in Corvallis. “If we can manage and manipulate microbiomes … this could potentially represent an untapped area for increasing plant yield in agricultural settings.” Meanwhile, scientists like Zahn are eyeing the microbiome to save endangered plants.

But before microbiome-based farming and conservation can truly take off, many questions need answers. Several revolve around the complex interactions between plants, their diverse microbial denizens and the environments they live in. One concern is that the microbes that help some plants might, under certain conditions, harm others elsewhere, warns microbiologist Luis Mejía of the Institute of Scientific Research and High Technology Services in Panama City.

Save the chocolate
Cacao crops — and thus humankind’s precious M&M’s supply — are under constant threat from undesirable fungi, such as Phytophthora palmivora, which causes black pod rot. But there are good guys in cacao’s microbiome too, particularly the fungus Colletotrichum tropicale, which seems to protect the trees.
Natalie Christian, as a graduate student at Indiana University Bloomington, traveled to the Smithsonian Tropical Research Institute on Panama’s Barro Colorado Island in 2014 to study how entire communities of microbes colonize and influence cacao plants (Theobroma cacao). Christian suspected that the prime source of a young cacao tree’s microbiome would be the dead and decaying leaves on the rainforest or orchard floor.

To test this hunch and see what kind of protection microbes picked up from leaf litter might offer, Christian raised fungus-free cacao seedlings in a lab incubator. When the plants reached about half a meter tall, she placed them in pots outside, surrounding some with leaf litter from a healthy cacao tree, some with litter from other kinds of trees and some with no litter at all.

After two weeks, she brought the plants back into the greenhouse to analyze their microbiomes. She found nearly 300 kinds of endophytes, which she, Mejía and colleagues reported last year in Proceedings of the Royal Society B.

The microbiome membership differed between the litter treatments. Plants in pots with either kind of leaf litter possessed less diverse microbiomes than those without litter, probably because the microbes in the litter quickly took over before stray microbes from elsewhere could settle in. These results suggest that a seedling in the shadow of more mature trees will probably accumulate the same microbiome as its towering neighbors.
To see if some of those transferred microbes protect the cacao from disease-causing organisms, Christian rubbed a bit of black pod rot on the leaves of plants in each group. Three weeks later, she measured the size of the rotted spots.

Plants surrounded by cacao litter had the smallest lesions. Those with litter from other trees had slightly more damage, and plants with no litter had about double the damage of the mixed litter plants.

“Getting exposed to the litter of their mother or their own kind had a very strong beneficial effect on the resistance of these young plants,” says plant biologist Keith Clay of Tulane University in New Orleans, a coauthor of the study.

Scientists aren’t sure how the good fungi protect the plants against the rot. It may be that the beneficial fungi simply take up space in or on the leaves, leaving no room for the undesirables, Christian says. Or a protective microbe like C. tropicale might attack a pathogen via some kind of chemical warfare. In the case of cacao, she thinks the most likely explanation is that the good guys act as a sort of vaccine, priming the plant’s immune system to fight off the rot. In support of this idea, Mejía reported in 2014 in Frontiers in Microbiology that C. tropicale causes cacao to turn on defensive genes.

Cacao farmers may need to rethink their practices. The farmers normally clear leaf litter out of orchards to avoid transmitting disease-causing microbes from decaying leaves to living trees, says Christian, now a postdoc at the University of Illinois at Urbana-Champaign. But her work suggests that farmers might do well to at least hold on to litter from healthy trees.

Crop questions
Litter is a low-tech way to spread entire communities of microbes — good and bad. But agricultural companies want to grab only the good microbes and apply them to crops. The hunt for the good guys starts with a stroll through a crop field, says Barry Goldman, vice president and head of discovery at Indigo Ag in Boston. Chances are, you’ll find bigger and hardier plants among the crowd. Within those top performers, Indigo has found endophytes that improve plant vigor and size, and others that protect against drought.

The company, working with cotton, corn, rice, soybeans and wheat, coats seeds with these microbes. Once the seeds germinate, the microbes cover the newborn leaves and can get inside via cuts in the roots or through stomata, tiny breathing holes in the leaves. The process is akin to what happens when a baby travels through the birth canal, picking up beneficial microbial partners from mom along the way.
For example, the first-generation Indigo Wheat, released in 2016, starts from seeds treated with a beneficial microbe. In Kansas test fields, the treatment raised yields by 8 to 19 percent.

Farmers are also reporting improved drought tolerance. During the first six months of 2018 with only two rains, the participating Kansas farmers had given up on and plowed over fields with struggling regular wheat, but not those growing Indigo Wheat, Goldman says.

In St. Louis, NewLeaf Symbiotics is interested in bacteria of the genus Methylobacterium. These microbes, found in all plants, are known as methylotrophs because they eat methanol, which plants release as their cells grow. In return for methanol, M-trophs, as NewLeaf calls them, offer plants diverse benefits. Some deliver molecules that encourage plants to grow; others make seeds germinate earlier and more consistently, or protect against problem fungi.

NewLeaf released its first products this year, including Terrasym 401, a seed treatment for soybeans. Across four years of field trials, Terrasym 401 raised yields by more than two bushels per acre, says NewLeaf cofounder and CEO Tom Laurita. One bushel is worth about $9. On farms with thousands of acres, that adds up.

Farmers are pleased, but NewLeaf’s and Indigo’s work is hardly done. Plant microbiome companies all face similar challenges. One is the diverse environments where crops are grown. Just because Indigo Wheat thrives in Kansas doesn’t mean it will outgrow standard varieties in, say, North Dakota. “The big ask for the next-gen ag biotech companies like AgBiome or Indigo … is whether the products will deliver as advertised over a range of field conditions,” Dangl says.

Another issue is that crop fields and plants already have microbiomes. “We’re asking a lot of a microbe, or a mix of microbes, to invade an already-existing ecosystem and persist there and do their job,” Dangl says. Companies will need to make sure their preferred microbes take hold.

And while scientists are well aware that diverse microbial communities cooperate to affect plant health, most companies are working with one kind of microbe at a time. Indigo isn’t yet sure how to approach entire microbiomes, Goldman says, but “we certainly are thinking hard about it.”

Researchers are beginning to address these questions by studying microbes in communities — such as Christian’s leaf-litter microbiomes — instead of as individuals. In the lab, Dangl developed a synthetic community of 188 root microbes. He can apply them to plants under stress from drought or heat, then watch how the communities respond and affect the plants.

A major aim is to identify the factors that determine microbiome membership. What decides who gets a spot on a given plant? How does the plant species and its local environment affect the microbiome? How do plants welcome friendlies and eject hostiles? “This is a huge area of importance,” Dangl says.

There’s some risk in adding microbes to crops while these questions are still unanswered, Mejía cautions. Microbes that are beneficial in one situation could be harmful in other plants or different environments. It’s not a far-fetched scenario: There’s a fungal endophyte of a South American palm tree that staves off beetle infestations when the trees are in the shade. Under the sun, however, the fungus turns nasty, spewing hydrogen peroxide that kills plant tissues.

And although C. tropicale benefits cacao, the genus has a dark side: Many species of Colletotrichum can cause leaf lesions and rotted fruit or flower spots in a variety of plants ranging from avocados to zinnias.
Microbes for conservation
Back in Hawaii, after that disheartening hike to the P. kaalaensis graveyard, Zahn pondered how to protect native plants in wild environments such as Oahu’s mountains.

In people, Zahn considered, antibiotics can damage normal gut microbe populations, leaving a person vulnerable to infection by harmful microbes. P. kaalaensis got similar treatment in the greenhouse, where it received regular dosing of fungicide. In retrospect, Zahn realized, that treatment probably left the plants bereft of their natural microbiome and weakened their immune systems, leaving them vulnerable to mildew infection once dropped into the jungle.

For people on antibiotics, probiotics — beneficial bacteria — can help restore balance. Zahn thought a similar strategy, a sort of plant probiotic, could help protect P. kaalaensis in future attempts at moving it outside.

For a probiotic, Zahn looked to a P. kaalaensis cousin, Phyllostegia hirsuta, which can survive in the wild. He put P. hirsuta leaves in a blender and sprayed the slurry over P. kaalaensis growing in an incubator.

Then, Zahn placed a leaf infected with powdery mildew into the incubator’s air intake. The mint plants treated with the P. hirsuta slurry experienced delayed, less severe infections compared with untreated plants, Zahn and Amend, also at the University of Hawaii at Manoa, reported last year in PeerJ. The probiotic had worked.

Zahn used DNA sequencing to identify the microbes in the slurry. Many of the microbiome members probably benefit P. kaalaensis, but he thinks he’s found a major protector: a yeast called Pseudozyma aphidis that lives on leaves. “This yeast normally just passively absorbs nutrients from the environment,” Zahn says. “But given the right victim, it will turn into a vicious spaghetti monster.” When mildew spores land nearby, the yeast grows tentacle-like filaments that appear to envelop and feed on the mildew.

Emboldened by his results, Zahn trekked back to the jungle and planted six slurry-treated plants in April 2016. They survived for about two years, but by May 2018, they were all dead.
“It was still a huge win,” says Nicole Hynson, a community ecologist also at Manoa. After all, P. kaalaensis without probiotics last only months. And the probiotics approach might apply beyond one little Hawaiian mint, Hynson adds: “We’re really at the beginning of thinking how we might use the microbiome to address plant restoration.”

Zahn has since moved to Utah Valley University in Orem, where he’s hoping to help endangered cacti with microbes. Meanwhile, he’s left the Phyllostegia project in the hands of Jerry Koko, a graduate student in Hynson’s lab. Koko is studying how the yeast and some root-based fungi protect the plant.

Hynson says their goal is to build “a superplant.” With probiotics on both roots and shoots, an enhanced P. kaalaensis should be well-equipped to grow strong and resist mildew. In greenhouse experiments so far, Koko says, the plants with both types of beneficial fungi seem to sport fewer, smaller powdery mildew patches than plants that received no probiotic treatment.

While the restoration of a little flowering plant, or a few more bushels of soybeans, may seem like small victories, they could herald big things for plant microbiomes in conservation as well as agriculture. The farmers and conservationists of the future may find themselves seeding and tending not just plants, but their microscopic helpers, too.

Beer lovers could be left with a sour taste, thanks to the latest in a series of studies mapping the effects of climate change on crops.

Malted barley — a key ingredient in beer including IPAs, stouts and pilsners — is particularly sensitive to warmer temperatures and drought, both of which are likely to increase due to climate change. As a result, average global barley crop yields could drop as much as 17 percent by 2099, compared with the average yield from 1981 to 2010, under the more extreme climate change projections, researchers report October 15 in Nature Plants.
That decline “could lead to, on average, a doubling of price in some countries,” says coauthor Steven Davis, an Earth systems scientist at University of California, Irvine. Consumption would also drop globally by an average of 16 percent, or roughly what people in the United States consumed in 2011.

The results are based on computer simulations projecting climate conditions, plant responses and global market reactions up to the year 2099. Under the mildest climate change predictions, world average barley yields would still go down by at least 3 percent, and average prices would increase about 15 percent, the study says.

Other crops such as maize, wheat and soy and wine grapes are also threatened by the global rising of average atmospheric temperatures as well as by pests emboldened by erratic weather (SN: 2/8/14, p. 3). But there’s still hope for ale aficionados. The study did not account for technological innovations or genetic tweaks that could spare the crop, Davis says.

What do you get when you flip a fossilized “jellyfish” upside down? The answer, it turns out, might be an anemone.

Fossil blobs once thought to be ancient jellyfish were actually a type of burrowing sea anemone, scientists propose March 8 in Papers in Palaeontology.

From a certain angle, the fossils’ features include what appears to be a smooth bell shape, perhaps with tentacles hanging beneath — like a jellyfish. And for more than 50 years, that’s what many scientists thought the animals were.
But for paleontologist Roy Plotnick, something about the fossils’ supposed identity seemed fishy. “It’s always kind of bothered me,” says Plotnick, of the University of Illinois Chicago. Previous scientists had interpreted one fossil feature as a curtain that hung around the jellies’ tentacles. But that didn’t make much sense, Plotnick says. “No jellyfish has that,” he says. “How would it swim?”

One day, looking over specimens at the Field Museum in Chicago, something in Plotnick’s mind clicked. What if the bell belonged on the bottom, not the top? He turned to a colleague and said, “I think this is an anemone.”

Rotated 180 degrees, Plotnick realized, the fossils’ shape — which looks kind of like an elongated pineapple with a stumpy crown — resembles some modern anemones. “It was one of those aha moments,” he says. The “jellyfish” bell might be the anemone’s lower body. And the purported tentacles? Perhaps the anemone’s upper section, a tough, textured barrel protruding from the seafloor.

Plotnick and his colleagues examined thousands of the fossilized animals, dubbed Essexella asherae, unearthing more clues. Bands running through the fossils match the shape of some modern anemones’ musculature. And some specimens’ pointy protrusions resemble an anemone’s contracted tentacles.
“It’s totally possible that these are anemones,” says Estefanía Rodríguez, an anemone expert at the American Museum of Natural History in New York City who was not involved with the work. The shape of the fossils, the comparison with modern-day anemones — it all lines up, she says, though it’s not easy to know for sure.

Paleontologist Thomas Clements agrees. Specimens like Essexella “are some of the most notoriously difficult fossils to identify,” he says. “Jellyfish and anemones are like bags of water. There’s hardly any tissue to them,” meaning there’s little left to fossilize.
Still, it’s plausible that the blobs are indeed fossilized anemones, says Clements, of Friedrich-Alexander-Universität Erlangen-Nürnberg in Germany. He was not part of the new study but has spent several field seasons at Mazon Creek, the Illinois site where Essexella lived some 310 million years ago. Back then, the area was near the shoreline, Clements says, with nearby rivers dumping sediment into the environment – just the kind of place ancient burrowing anemones may have once called home.

Weird materials called Weyl metals might reveal the secrets of how Earth gets its magnetic field.

The substances could generate a dynamo effect, the process by which a swirling, electrically conductive material creates a magnetic field, a team of scientists reports in the Oct. 26 Physical Review Letters.

Dynamos are common in the universe, producing the magnetic fields of the Earth, the sun and other stars and galaxies. But scientists still don’t fully understand the details of how dynamos create magnetic fields. And, unfortunately, making a dynamo in the lab is no easy task, requiring researchers to rapidly spin giant tanks of a liquefied metal, such as sodium (SN: 5/18/13, p. 26).
First discovered in 2015, Weyl metals are topological materials, meaning that their behavior is governed by a branch of mathematics called topology, the study of shapes like doughnuts and knots (SN: 8/22/15, p. 11). Electrons in Weyl metals move around in bizarre ways, behaving as if they are massless.

Within these materials, the researchers discovered, electrons are subject to the same set of equations that describes the behavior of liquids known to form dynamos, such as molten iron in the Earth’s outer core. The team’s calculations suggest that, under the right conditions, it should be possible to make a dynamo from solid Weyl metals.

It might be easier to create such dynamos in the lab, as they don’t require large quantities of swirling liquid metals. Instead, the electrons in a small chunk of Weyl metal could flow like a fluid, taking the place of the liquid metal.
The result is still theoretical. But if the idea works, scientists may be able to use Weyl metals to reproduce the conditions that exist within the Earth, and better understand how its magnetic field forms.

Neandertals are shaking off their reputation as head bangers.

Our close evolutionary cousins experienced plenty of head injuries, but no more so than late Stone Age humans did, a study suggests. Rates of fractures and other bone damage in a large sample of Neandertal and ancient Homo sapiens skulls roughly match rates previously reported for human foragers and farmers who have lived within the past 10,000 years, concludes a team led by paleoanthropologist Katerina Harvati of the University of Tübingen in Germany.
Males suffered the bulk of harmful head knocks, whether they were Neandertals or ancient humans, the scientists report online November 14 in Nature.

“Our results suggest that Neandertal lifestyles were not more dangerous than those of early modern Europeans,” Harvati says.

Until recently, researchers depicted Neandertals, who inhabited Europe and Asia between around 400,000 and 40,000 years ago, as especially prone to head injuries. Serious damage to small numbers of Neandertal skulls fueled a view that these hominids led dangerous lives. Proposed causes of Neandertal noggin wounds have included fighting, attacks by cave bears and other carnivores and close-range hunting of large prey animals.

Paleoanthropologist Erik Trinkaus of Washington University in St. Louis coauthored an influential 1995 paper arguing that Neandertals incurred an unusually large number of head and upper-body injuries. Trinkaus recanted that conclusion in 2012, though. All sorts of causes, including accidents and fossilization, could have resulted in Neandertal skull damage observed in relatively small fossil samples, he contended (SN: 5/27/17, p. 13).
Harvati’s study further undercuts the argument that Neandertals engaged in a lot of violent behavior, Trinkaus says.

Still, the idea that Neandertals frequently got their heads bonked during crude, close-up attacks on prey has persisted, says paleoanthropologist David Frayer of the University of Kansas in Lawrence. The new report highlights the harsh reality that, for Neandertals and ancient humans alike, “head trauma, no matter the level of technological or social complexity, or population density, was common.”

Harvati’s group analyzed data for 114 Neandertal skulls and 90 H. sapiens skulls. All of these fossils were found in Eurasia and date to between around 80,000 and 20,000 years ago. One or more head injuries appeared in nine Neandertals and 12 ancient humans. After statistically accounting for individuals’ sex, age at death, geographic locations and state of bone preservation, the investigators estimated comparable levels of skull damage in the two species. Statistical models run by the team indicate that skull injuries affected an average of 4 percent to 33 percent of Neandertals, and 2 percent to 34 percent of ancient humans.

Estimated prevalence ranges that large likely reflect factors that varied from one locality to another, such as resource availability and hunting conditions, the researchers say.

Neandertals with head wounds included more individuals under age 30 than observed among their human counterparts. Neandertals may have suffered more head injuries early in life, the researchers say. It’s also possible that Neandertals died more often from head injuries than Stone Age humans did.

Researchers have yet to establish whether Neandertals experienced especially high levels of damage to body parts other than the head, writes paleoanthropologist Marta Mirazón Lahr of the University of Cambridge in a commentary in Nature accompanying the new study.

Oceans may be shrinking — Science News, March 10, 1973

The oceans of the world may be gradually shrinking, leaking slowly away into the Earth’s mantle…. Although the oceans are constantly being slowly augmented by water carried up from Earth’s interior by volcanic activity … some process such as sea-floor spreading seems to be letting the water seep away more rapidly than it is replaced.

Update
Scientists traced the ocean’s leak to subduction zones, areas where tectonic plates collide and the heavier of the two sinks into the mantle. It’s still unclear how much water has cycled between the deep ocean and mantle through the ages. A 2019 analysis suggests that sea levels have dropped by an average of up to 130 meters over the last 230 million years, in part due to Pangea’s breakup creating new subduction zones. Meanwhile, molten rock that bubbles up from the mantle as continents drift apart may “rain” water back into the ocean, scientists reported in 2022. But since Earth’s mantle can hold more water as it cools (SN: 6/13/14), the oceans’ mass might shrink by 20 percent every billion years.

A new species of hulking ancient herbivore would have overshadowed its relatives.

Fossils found in Poland belong to a new species that roamed during the Late Triassic, a period some 237 million to 201 million years ago, researchers report November 22 in Science. But unlike most of the enormous animals who lived during that time period, this new creature isn’t a dinosaur — it’s a dicynodont.

Dicynodonts are a group of ancient four-legged animals that are related to mammals’ ancestors. They’re a diverse group, but the new species is far larger than any other dicynodont found to date. The elephant-sized creature was more than 4.5 meters long and probably weighed about nine tons, the researchers estimate. Related animals didn’t become that big again until the Eocene, 150 million years later.
“We think it’s one of the most unexpected fossil discoveries from the Triassic of Europe,” says study coauthor Grzegorz Niedzwiedzki, a paleontologist at Uppsala University in Sweden. “Who would have ever thought that there is a fossil record of such a giant, elephant-sized mammal cousin in this part of the world?” He and his team first described some of the bones in 2008; now they’ve made the new species — Lisowicia bojani — official.

The creature had upright forelimbs like today’s rhinoceroses and hippos, instead of the splayed front limbs seen on other Triassic dicynodonts, which were similar to the forelimbs of present-day lizards. That posture would have helped it support its massive bodyweight.