An ancient vegetarian dinosaur from the French countryside has given paleontologists something to sink their teeth into.

The most striking feature of a new species of rhabdodontid that lived from 84 million to 72 million years ago is its oversized, scissorslike teeth, paleontologist Pascal Godefroit, of the Royal Belgian Institute of Natural Sciences in Brussels, and his colleagues report October 26 in Scientific Reports. Compared with other dinos of its kind, Matheronodon provincialis’ teeth were at least twice as large but fewer in number. Some teeth reached up to 6 centimeters long, while others grew up to 5 centimeters wide. They looked like a caricature of normal rhabdodontid teeth, Godefroit says.
Of hundreds of fossils unearthed over the last two decades at a site called Velaux-La Bastide Neuve in the French countryside, a handful of jaw bones and teeth now have been linked to this new species, Matheronodon provincialis. The toothy dino belongs to a group of herbivorous, bipedal dinosaurs common in the Cretaceous Period. Rhabdodontids sported bladelike teeth, and likely noshed on the tough woody tissue parts of plants. Palm trees, common in Europe at the time, might have been on the menu.

Rhabdodontid teeth have ridges covered by a thick layer of enamel on one side and little to no ridges or enamel on the other. Teeth in the upper jaw have more ridges and enamel on the outer edge, while the reverse is true for bottom teeth. A closer look at the microstructure of M. provincialis’ teeth revealed an exaggerated version of this — many more ridges and lopsided enamel coating. Enamel typically protects from wear and tear, so chewing would have sharpened the dino’s teeth. “They operated like self-sharpening serrated scissors,” Godefroit says.

Light-sensitive cells in the eyes of some fish do double-duty. In pearlsides, cells that look like rods — the stars of low-light vision — actually act more like cones, which only respond to brighter light, researchers report November 8 in Science Advances. It’s probably an adaptation to give the deep-sea fish acute vision at dawn and dusk, when they come to the surface of the water to feed.

Rods and cones studding the retina can work in tandem to give an animal good vision in a wide variety of light conditions. Some species that live in dark environments, like many deep-sea fish, have dropped cones entirely. But pearlside eyes have confused scientists: The shimmery fish snack at the water’s surface at dusk and dawn, catching more sun than fish that feed at night. Most animals active at these times of day use a mixture of rods and cones to see, but pearlside eyes appear to contain only rods.
“That’s actually not the case when you look at it in more detail,” says study coauthor Fanny de Busserolles, a sensory biologist at the University of Queensland in Australia.

She and her colleagues investigated which light-responsive genes those rod-shaped cells were turning on. The cells were making light-sensitive proteins usually found in cones, the researchers found, rather than the rod-specific versions of those proteins.

These rodlike cones still have the more elongated shape of a rod. And like regular rods, they are sensitive to even small amounts of light. But the light-absorbing proteins inside match those found in cones, and are specifically tuned to respond to the blue wavelengths of light that dominate at dawn and dusk, the researchers found. The fish don’t have color vision, though, which relies on having different cones sensitive to different wavelengths of light.

“Pearlsides found a more economical and efficient way of seeing in these particular light conditions by combining the best characteristics of both cell types into a single cell,” de Busserolles says.
A few other animals have also been found to have photoreceptors that fall somewhere between traditional rods and cones, says Belinda Chang, an evolutionary biologist at the University of Toronto who wasn’t involved in the study. Chang’s lab recently identified similar cells in the eyes of garter snakes. “These are thought to be really cool and unusual receptors,” she says.

Together, finds like these begin to challenge the idea that rods and cones are two separate visual systems, de Busserolles says. “We usually classify photoreceptors into rods or cones only,” she says. “Our results clearly show that the reality is more complex than that.”

Thousands of years ago, hunter-gatherers native to Europe and incoming farmers from what’s now Turkey got up close and personal for a surprisingly long time, researchers say. This mixing reshaped the continent’s genetic profile differently from one region to another.

Ancient DNA from foragers and farmers in eastern, central and western Europe indicates that they increasingly mated with each other from around 8,000 to nearly 4,000 years ago, a team led by geneticist Mark Lipson of Harvard Medical School in Boston reports online November 8 in Nature. That time range covers much of Europe’s Neolithic period, which was characterized by the spread of farming, animal domestication and polished stone tools.
The new findings lend support to the idea that Europe and western Asia witnessed substantial human population growth and migrations during the Neolithic, says archaeologist Peter Bellwood of Australian National University in Canberra. So much mating occurred over such a long time that “geneticists can no longer assume that living people across Europe are a precise reflection of European genetic history,” he says.
Previous studies of ancient DNA indicated that farmers in Anatolia (modern Turkey) migrated into Europe roughly 8,000 years ago. Researchers generally assumed that newcomers and native hunter-gatherers interbred at first, perhaps as a single wave of farmers moved through Europe to the Atlantic coast, Lipson says. From this perspective, foragers either joined farming cultures or abandoned their home territories and scattered elsewhere. But it now appears that, after a major migration of farmers into Europe, many groups of farmers and hunter-gatherers living in particular regions mingled to varying extents for many centuries, the researchers say.
“Even though there weren’t any major new migrations into Europe after the arrival of farmers, there were ongoing ancestry changes throughout the Neolithic due to interactions between farmers and hunter-gatherers,” Lipson says. Central and northern Europeans next experienced large DNA changes at the start of the Bronze Age around 5,000 years ago, with the arrival of nomadic herders from western Asia (SN: 7/11/15, p. 11).

Lipson’s team analyzed DNA extracted from the skeletons of 154 farmers from Hungary, Germany and Spain, dating to around 8,000 to 4,200 years ago. The farmers’ DNA was compared with DNA from three Neolithic hunter-gatherers found in Hungary, Luxembourg and Spain; a fourth hunter-gatherer from Italy dating to about 14,000 years ago; and 25 Anatolian farmers from as early as 8,500 years ago.

Farmers in each European region displayed increasing amounts of hunter-gatherer ancestry over time, with highs of about 10 percent in Hungary and 20 percent in Germany by around 5,000 years ago, and about 30 percent in Spain by 4,200 years ago. Three farmers from a 6,000-year-old site in Germany fell outside the general trend for that part of Neolithic Europe, displaying 40 to 50 percent hunter-gatherer ancestry.

Genes got passed from farmers to hunter-gatherers as well, although skeletal remains of Neolithic hunter-gatherers are much scarcer than those of their cultivating contemporaries. A hunter-gatherer from the 6,000-year-old German site, identified via chemical markers of diet in the bones, carried around 27 percent ancestry from farmers. A hunter-gatherer discovered at a Hungarian farming site dating to roughly 7,700 years ago possessed about 20 percent ancestry from farmers. Still, previous work has shown neighboring European farmers and hunter-gatherers sometimes kept their distance (SN: 11/16/13, p. 13).

Despite this unexpected evidence of long-term mating among communities with different cultures and styles, the tempo of genetic change and the population sizes of farmers and hunter-gatherers remain poorly understood, says archaeologist Alasdair Whittle of Cardiff University in Wales.

A misfit gang of superconducting materials may be losing their outsider status.

Certain copper-based compounds superconduct, or transmit electricity without resistance, at unusually high temperatures. It was thought that the standard theory of superconductivity, known as Bardeen-Cooper-Schrieffer theory, couldn’t explain these oddballs. But new evidence suggests that the standard theory applies despite the materials’ quirks, researchers report in the Dec. 8 Physical Review Letters.

All known superconductors must be chilled to work. Most must be cooled to temperatures that hover above absolute zero (–273.15° Celsius). But some copper-based superconductors work at temperatures above the boiling point of liquid nitrogen (around –196° C). Finding a superconductor that functions at even higher temperatures — above room temperature — could provide massive energy savings and new technologies (SN: 12/26/15, p. 25). So scientists are intent upon understanding the physics behind known high-temperature superconductors.
When placed in a magnetic field, many superconductors display swirling vortices of electric current — a hallmark of the standard superconductivity theory. But for the copper-based superconductors, known as cuprates, scientists couldn’t find whirls that matched the theory’s predictions, suggesting that a different theory was needed to explain how the materials superconduct. “This was one of the remaining mysteries,” says physicist Christoph Renner of the University of Geneva. Now, Renner and colleagues have found vortices that agree with the theory in a high-temperature copper-based superconductor, studying a compound of yttrium, barium, copper and oxygen.

Vortices in superconductors can be probed with a scanning tunneling microscope. As the microscope tip moves over a vortex, the instrument records a change in the electrical current. Renner and colleagues realized that, in their copper compound, there were two contributions to the current that the probe was measuring, one from superconducting electrons and one from nonsuperconducting ones. The nonsuperconducting contribution was present across the entire surface of the material and masked the signature of the vortices.

Subtracting the nonsuperconducting portion revealed the vortices, which behaved in agreement with the standard superconductivity theory. “That, I think, is quite astonishing; it’s quite a feat,” says Mikael Fogelström of Chalmers University of Technology in Gothenburg, Sweden, who was not involved with the research.
The result lifts some of the fog surrounding cuprates, which have so far resisted theoretical explanation. But plenty of questions still surround the materials, Fogelström says. “It leaves many things still open, but it sort of gives a new picture.”

One person infected with strep bacteria might get a painful sore throat; another might face a life-threatening blood infection. Now, scientists are trying to pin down why.

Variation between individuals’ immune systems may not be entirely to blame. Instead, extra genes picked up by some pathogens can cause different strains to have wildly different effects on the immune system, even in the same person, researchers report January 11 in PLOS Pathogens.

The idea that different strains of bacteria can behave differently in the body isn’t new. Take E. coli: Some strains of the bacteria that can cause foodborne illness make people far sicker than other strains­. But bacteria have exceptionally large amounts of genetic variation, even between members of the same species. Scientists are still trying to figure out how that genetic diversity affects the way microbes interact with the immune system.
Any species of bacteria has a core set of genes that all its members share. Then there’s a whole pot of genes that different strains of the species pick and choose to create what’s known as an accessory genome. These genes are custom add-ons that specific strains have acquired over time, from their environment or from other microbes — something like an expansion pack for a card game. Sometimes, that extra genetic material gives bacteria new traits.

Uri Sela and his colleagues at the Rockefeller University in New York City tested the way these extra genes influenced the way two common species of bacteria, Staphylococcus aureus and Streptococcus pyogenes, interacted with the immune system. Staphylococcus bacteria can cause everything from rashes to food poisoning to blood infections. Streptococcus bacteria can cause strep throat, as well as a host of more serious illnesses (SN: 10/4/14, p. 22).

Different strains of the same species provoked wildly different immune responses in blood samples collected from the same patient, the researchers first showed. But the strain-specific responses were consistent across patients. Some strains triggered lots of T cells to be made in every sample, for example; others increased B cell activity. (T cells and B cells are the two main weapons of the adaptive immune response, which enables the body to build long-lasting immunity against a particular pathogen.) In tests of strains missing some of their extra genes, though, the T cells didn’t respond as strongly as they did to a matching strain that contained the extra genes. This finding suggests that the variation in immune response across strains was coming, at least in part, from differences in these supplementary genes.
“Currently when a patient comes to the hospital with an infection, we don’t define the strain of the species” for common infections like strep and staph, says Sela, an immunologist. In the future, he says, information about the strain could help doctors predict how a patient’s illness will unfold and decide on the best treatment.

The new study “adds fuel to an active debate” about the role of accessory genes, says Alan McNally, a microbiologist at the University of Birmingham in England — whether or not the collections of genetic add-ons that bacteria maintain are shaped by natural selection, the process that fuels evolution. This research suggests that for some kinds of bacteria, genetic customization might aid survival of certain strains by enabling them to provoke a tailored immune response.

But more research needs to be done to link the strain-to-strain variation in immune response to the accessory genome, he says, as this study looked at only a few extra genes, not the entire accessory genome.

Volcano-fueled holes in Earth’s ozone layer 252 million years ago may have repeatedly sterilized large swaths of forest, setting the stage for the world’s largest mass extinction event. Such holes would have allowed ultraviolet-B radiation to blast the planet. Even radiation levels below those predicted for the end of the Permian period damage trees’ abilities to make seeds, researchers report February 7 in Science Advances.

Jeffrey Benca, a paleobotanist at the University of California, Berkeley, and his colleagues exposed plantings of modern dwarf pine tree (Pinus mugo) to varying levels of UV-B radiation. Those levels ranged from none to up to 93 kilojoules per square meter per day. According to previous simulations, UV-B radiation at the end of the Permian may have increased from a background level of 10 kilojoules (just above current ambient levels) to as much as 100 kilojoules, due to large concentrations of ozone-damaging halogens spewed from volcanoes (SN: 1/15/11, p. 12).

Exposure to higher UV-B levels led to more malformed pollen, the researchers found, with up to 13 percent of the pollen grains deformed under the highest conditions. And although the trees survived the heightened irradiation, the trees’ ovulate cones — cones that, when fertilized by pollen, become seeds — did not. But the trees weren’t permanently sterilized: Once removed from extra UV-B exposure, the trees could reproduce again.

The finding supports previous research suggesting that colossal volcanic eruptions in what’s now Siberia, about 300,000 years before the onset of the extinction event, probably triggered the die-off of nearly all marine species and two-thirds of species living on land (SN: 9/19/15, p. 10). Repeated pulses of volcanism at the end of the Permian may have led to several periods of irradiation that sterilized the forests, causing a catastrophic breakdown of food webs, the researchers say — an indirect but effective way to kill.

AUSTIN, Texas — Stretchy sensors that stick to the throat could track the long-term recovery of stroke survivors.

These new Band-Aid‒shaped devices contain motion sensors that detect muscle movement and vocal cord vibrations. That sensor data could help doctors diagnose and monitor the effectiveness of certain treatments for post-stroke conditions like difficulty swallowing or talking, researchers reported February 17 in a news conference at the annual meeting of the American Association for the Advancement of Science. Up to 65 percent of stroke survivors have trouble swallowing, and about a third of survivors have trouble carrying on conversations.
The devices can monitor speech patterns more reliably than microphones by sensing tissue movement rather than recording sound. “You don’t pick up anything in terms of ambient noise,” says study coauthor John Rogers, a materials scientist and bioengineer at Northwestern University in Evanston, Ill. “You can be next to an airplane jet engine. You’re not going to see that in the [sensor] signal.”

Developed by Rogers’ team, the sensors have built-in 12-hour rechargeable batteries and continually stream motion data to a smartphone. Researchers are now testing the sensors with real stroke patients to see how the devices can be made more user-friendly. For instance, Rogers’ team realized that patients were unlikely to wear sensors that were too easily visible. By equipping the patches with more sensitive motion sensors, they can be worn lower on a person’s neck, hidden behind a buttoned-up shirt, and still pick up throat motion.

These kinds of sensors could also track the recovery of neck cancer patients, who commonly develop swallowing and speaking problems caused by radiation therapy and surgery, Rogers says. The devices can also measure breathing and heart rates to monitor sleep quality and help diagnose sleep apnea. Rogers expects this wearable tech to be ready for widespread use within the next year or two.

With fevers, chills and aches, the flu can pound the body. Some influenza viruses may hammer the brain, too. Months after being infected with influenza, mice had signs of brain damage and memory trouble, researchers report online February 26 in the Journal of Neuroscience.

It’s unclear if people’s memories are affected in the same way as those of mice. But the new research adds to evidence suggesting that some body-wracking infections could also harm the human brain, says epidemiologist and neurologist Mitchell Elkind of Columbia University, who was not involved in the study.
Obvious to anyone who has been waylaid by the flu, brainpower can suffer at the infection’s peak. But not much is known about any potential lingering effects on thinking or memory. “It hasn’t occurred to people that it might be something to test,” says neurobiologist Martin Korte of Technische Universität Braunschweig in Germany.

The new study examined the effects of three types of influenza A — H1N1, the strain behind 2009’s swine flu outbreak; H7N7, a dangerous strain that only rarely infects people; and H3N2, the strain behind much of the 2017–2018 flu season misery (SN: 2/17/18, p. 12). Korte and colleagues shot these viruses into mice’s noses, and then looked for memory problems 30, 60 and 120 days later.

A month after infection, the mice all appeared to have recovered and gained back weight. But those that had received H3N2 and H7N7 had trouble remembering the location of a hidden platform in a pool of water, the researchers found. Mice that received no influenza or the milder H1N1 virus performed normally at the task.
Researchers also studied the brain tissue of the infected mice under a microscope and found that the memory problems tracked with changes in nerve cells. A month after H7N7 or H3N2 infection, mice had fewer nerve cell connectors called dendritic spines on cells in the hippocampus, a brain region involved in memory. Electrical experiments on the nerve cell samples in dishes also suggested the cells’ signal-sending abilities were impaired.
What’s more, these mice’s brains looked inflamed under the microscope, full of immune cells called microglia that were still revved up 30 and 60 days after infection. Cell counts revealed that mice that had suffered through H3N2 or H7N7 had more active microglia than mice infected with H1N1 or no virus at all. That lingering activity was surprising, Korte says; most immune cells in the body usually settle down soon after an infection clears.

These memory problems and signs of brain trouble were gone by 120 days, which translates to about a decade in human time, Korte says. “I’m not saying that everyone who has influenza is cognitively impaired for 10 years,” he says, noting that human brains are much more complex than those of mice. “The news is more that we should not only look at lung functionality after the flu, but also cognitive effects, weeks and months after infection.”

H7N7 can infect brain cells directly. But H1N1 and H3N2 don’t typically get into the brain (and Korte and colleagues confirmed that in their experiments). Some flu viruses may be causing brain trouble remotely, perhaps through inflammatory signals in the blood making their way into the brain, the study suggests. If that pathway is confirmed, then many types of infections could cause similar effects on the brain. “It is plausible that this is a general phenomenon,” Elkind says.