Fledgling crustaceans have eyes like the sea, a peculiarity that could help them hide from predators.

Young shrimp, crab or lobster larvae already rock nearly translucent bodies to stay out of view. But dark eye pigments essential for vision pose the risk of exposing the animals anyway.

Some see-through ocean animals rely on mirrored irises or minuscule eyes to avoid detection. Young shrimp and prawns, on the other hand, camouflage their dark pigments behind light-reflecting glass made of tiny, crystalline spheres, researchers report in the Feb. 17 Science.
Variations in the size and placement of the orbs allow the crustaceans’ eyes to shine light that precisely matches the color of the surrounding water, possibly rendering them invisible to predators on the hunt for a meal.

Technologies that mimic the nanospheres’ structure could one day inspire more efficient solar energy or bio-friendly paints, the scientists say.

“I’ve often wondered what’s going on with [these animals’] eyeshine,” says evolutionary biologist Heather Bracken-Grissom of Florida International University in Miami, who was not involved in the study. She and colleagues often collect crustaceans from the deep sea, giving them nicknames like “blue-eyed arthropod” or “green-eyed, weird-looking shrimp” because the creatures don’t resemble their adult forms. Now, she says, that eye color makes sense.

In the study, chemist Keshet Shavit and colleagues used an electron microscope to peer into the eyes of lab-raised and wild crustaceans. Inside shrimp and prawn eyes, the team found crystalline nanospheres made of isoxanthopterin, a molecule that reflects light.

The spheres are a bit like disco balls, with highly reflective surfaces pointing outward, says study coauthor Benjamin Palmer, a chemist at Ben-Gurion University of the Negev in Beer-Sheva, Israel. Each sphere is made of thin, isoxanthopterin plates that stick together to form balls that range in size from around 250 to 400 nanometers in diameter.

These balls are arranged in clusters at the base of protein-dense cones that focus light on the animal’s light-sensing nerves, and form a protective cover over the pigmented cells. But crustacean larvae can still see because there are small holes in the glass, Palmer says. “It’s basically allowing light to go down to the retina on some specific angles, but on other angles, it’s reflecting light back.”
The size and order of the spheres seem to influence the color of the reflected light, the team’s observations and computer simulations show.

“The correlation between the particle size and the eyeshine color is beyond amazing,” says Shavit, also at Ben-Gurion University. Nanosphere size appears to help the animals’ eyes match the color of their native habitat, helping the critters blend into the background.

Blue-eyed shrimp that inhabit the Gulf of Aqaba’s clear blue waters off the coast of Israel, for instance, have spheres that are approximately 250 to 325 nanometers in diameter. The 400-nanometer-wide spheres of a freshwater prawn (Macrobrachium rosenbergii) glitter yellow-green, mimicking muddy waters found in the salty estuaries where they live.
The prawn’s eyes also seem to be able to reflect different colors in different environments. Individuals exposed to sunlight for four hours in the lab had silvery yellow eyes, possibly a result of nanospheres arranged in a disorganized jumble. But individuals left in the dark overnight had green eyes. Their nanospheres are arranged in layers — though the orbs within each layer are still disorganized, Palmer says.

Such adaptable eyes could help larvae move undetected through different parts of the ocean as changing light levels alter the color of the water, Bracken-Grissom says. At night, young crustaceans migrate to shallow waters to feed and dive back down when the sun rises. “If they are in fact using it as a form of camouflage, it would be an ingenious way to camouflage themselves as they move through these different light environments.”

Following the most severe known mass extinction in Earth’s history, vibrant marine ecosystems may have recovered within just a million years, researchers report in the Feb. 10 Science. That’s millions of years faster than previously thought. The evidence, which lies in a diverse trove of pristine fossils discovered near the city of Guiyang in South China, may represent the early foundations of today’s ocean-dwelling ecosystems.

The conventional story was that the ocean was kind of dead for millions of years after this mass extinction, says paleontologist Peter Roopnarine of the California Academy of Sciences in San Francisco, who was not involved in the research. “Well, that’s not true. The ocean [was] very much alive.”
The Great Dying, or Permian-Triassic mass extinction, occurred around 251.9 million years ago, at the end of the Permian Period, after a series of massive volcanic eruptions (SN: 12/6/18).

“The oceans warmed significantly, and there’s evidence for acidification, deoxygenation [causing widespread dead zones], as well as poisoning,” says Roopnarine. “There [were] a lot of toxic elements like sulfur entering into parts of the ocean.”

Life in the seas suffered. More than 80 percent of marine species went extinct. Some researchers have even proposed that entire trophic levels — castes in an ecosystem’s food web — may have vanished.

Figuring out how long life took to fully recover in the wake of all that loss has been challenging. In 2010, researchers studying fossils from the Luoping biota in China proposed that complex marine ecosystems fully rebounded within 10 million years. Later, other fossil finds, such as the Paris biota in the western United States and the Chaohu biota in China, led scientists to suggest that marine ecosystems reestablished themselves within just 3 million years.

Then in 2015, a serendipitous discovery narrowed the gap again. Paleontologist Xu Dai, then an undergraduate student at the China University of Geosciences in Wuhan, was studying rocks from the early Triassic during a field trip near the city of Guiyang, when he split open a piece of black shale. Within the rock, he discovered a surprisingly well-preserved fossil of what would later be identified as a primitive lobster.

The arthropod’s immaculate condition sparked a series of return trips. From 2015 to 2019, Dai, now at the University of Burgundy in Dijon, France, and his colleagues uncovered a bricolage of fossilized life: Predatory fish as long as baseball bats. Ammonoids in swirled shells. Eel-like conodonts. Early shrimps. Sponges. Bivalves. Fossilized poo.
And the prizes kept coming. Both under and within the Guiyang biota, Dai and his colleagues discovered beds of volcanic ash. An analysis of the amounts of uranium and lead in the ash revealed that the Guiyang biota contained fossils from roughly 250.7 to 250.8 million years ago (SN: 5/2/22). The dating was further supported by the types of fossils found and by an analysis of the different forms of carbon in the rocks.

Finding a potpourri of life of this age suggests that marine ecosystems rebounded quickly after the Great Dying, within just 1 million years or so, Dai says.

Alternatively, it may indicate that the extinction event failed to wipe out entire trophic levels, says paleontologist William Foster from the University of Hamburg in Germany, who was not involved in the study. “You have this really environmentally stressful world, but some former marine ecosystems survive.”

Regardless, it seems clear that these ecosystems were hardy. Due to the motion of tectonic plates, the community preserved in the Guiyang biota was located in the tropics during the early Triassic. At that time, the temperature of the sea surface was nearly 35⁰ Celsius, and past research had suggested many organisms may have migrated away to escape the heat. But, the discovery of the Guiyang biota challenges that, Foster says. Sea creatures “are tolerating it somehow, they’re adapting.”

According to Dai, the fossils may be evidence that the roots of today’s marine ecosystems took hold shortly after the Great Dying. “These groups are related to modern fish, lobsters and shrimps, their ancestors,” he says. “The oldest time we can find similar seafood to today is [in the time of] the Guiyang biota.”

But Roopnarine is skeptical. It remains to be seen exactly how the Guiyang biota connects to today’s ecosystems, he says. The fossil assemblage could represent an ephemeral collective of life rather than a stable community, he adds, pointing out that ammonoids and conodonts went extinct.

Further work will help resolve the many questions unearthed with the Guiyang biota, Dai says. He and his colleagues plan to head back into the field this summer for the first time since 2019. When asked if he’ll be keeping his eyes peeled for another lobster, he responds: “Of course.”

Nearly 3 million years ago, hominids employed stone tool kits to butcher hippos and pound plants along what’s now the shores of Kenya’s Lake Victoria, researchers say.

Evidence of those food preparation activities pushes back hominids’ use of these tool kits, known as Oldowan implements, by roughly 300,000 years, say paleoanthropologist Thomas Plummer of Queen’s College, City University of New York and colleagues. That makes these finds possibly the oldest known stone tools.

Several dating techniques place discoveries at the Kenyan site, known as Nyayanga, at between around 2.6 million and 3 million years old. Based on where artifacts lay in dated sediment layers, these finds are probably close to about 2.9 million years old, the scientists report in the Feb. 10 Science.
Until now, the oldest Oldowan tools dated to roughly 2.6 million years ago at an Ethiopian site more than 1,200 kilometers north of Nyayanga (SN: 6/3/19). Excavations at another site in Kenya, called Lomekwi 3, have yielded large, irregularly shaped rocks dating to about 3.3 million years ago (SN: 5/20/15). But claims that these finds, which include some sharp edges, represent the oldest known stone tools are controversial.

Similarities of the Nyayanga artifacts to those found at sites dating to as late as around 1.7 million years ago “reinforce the long trajectory of Oldowan technology in the early stages of human evolution,” says archaeologist Manuel Domínguez-Rodrigo of Rice University in Houston and the University of Alcalá in Madrid. He did not participate in the new study.

Skeletal remains of at least three hippos unearthed near a total of 56 stone artifacts at Nyayanga display butchery marks, the investigators say. Wear patterns on another 30 stone tools from Nyayanga indicate that these items were used to cut, scrape and pound animal tissue and a variety of plants. And antelope fossils found at Nyayanga display damage from hominids removing meat with sharp stones and crushing bones with large stones to remove marrow.
These discoveries are among 330 Oldowan artifacts and 1,776 animal bones unearthed at Nyayanga from 2015 through 2017. Oldowan finds included three parts of an ancient tool kit — rounded hammerstones, angular or oval cores and sharp-edged flakes. Toolmakers struck a core held in one hand with a hammerstone held in the other hand, splitting off flakes that could be used to cut or scrape.

Whoever wielded stone tools at the Kenya site close to 3 million years ago “had access to a well-balanced diet for hunter-gatherers,” says coauthor Rick Potts, a paleoanthropologist at the Smithsonian Institution in Washington, D.C.
The evolutionary identity of ancient Nyayanga toolmakers remains a mystery. Plummer’s group unearthed two large, peg-shaped molars belonging to Paranthropus, a big-jawed, small-brained hominid line that inhabited eastern and southern parts of Africa until around 1 million years ago. The Nyayanga teeth are the oldest known Paranthropus fossils.

But there is no way to confirm that Paranthropus made and used the newly recovered stone tools. Individuals who died at Nyayanga and left behind their fossilized teeth were not necessarily part of groups that periodically butchered hippos there, Domínguez-Rodrigo says.

Members of the Homo genus appeared in East Africa as early as around 2.8 million years ago and could have made Oldowan tools at Nyayanga, says archaeologist Sileshi Semaw of the National Research Center for Human Evolution in Burgos, Spain (SN: 3/4/15). But Paranthropus can’t be discounted as a toolmaker. A large male Paranthropus skull discovered in 1959, dubbed Nutcracker Man, lay near Oldowan artifacts dated to 1.89 million years ago, says Semaw, who was not part of Plummer’s group (SN: 3/3/20).

Previous discoveries indicated that Oldowan toolmakers eventually occupied much of Africa, Asia and Europe, either via the spread of toolmaking groups or through independent inventions.

Discoveries at Nyayanga fit a current consensus that stone-tool making must have begun shortly after hominids evolved substantially smaller canine teeth around 5 million years ago, says archaeologist John Shea of Stony Brook University in New York, who was not involved in the new study. Stone tools did the work formerly performed by big canines, including slicing prey carcasses, mashing edible plants and helping individuals communicate anger or dominance over others, Shea suspects.

If that tool-crafting timeline is correct, then even Australopithecus afarensis, known for Lucy’s famous partial skeleton, might have made and used stone tools by around 3.4 million years ago (SN: 8/11/10).

Any way you slice it, Oldowan finds at Nyayanga now provide the earliest hard evidence of stone tools.

Modern birds evolved from dinosaurs, but it’s not clear how well birds’ ancient dino ancestors could fly (SN: 10/28/16). Now, a look at the fossilized feet of one nonavian dinosaur suggests that it may have hunted on the wing, like some hawks today.

The crow-sized Microraptor had toe pads very similar to those of modern raptors that can hunt in the air, researchers report December 20 in Nature Communications. That means the feathered, four-winged dinosaur probably used its feet to catch flying prey too, paleobiologist Michael Pittman of the Chinese University of Hong Kong and colleagues say (SN: 7/16/20).
Other researchers caution that toe pads alone aren’t enough to declare Microraptor an aerial hunter. But if the claim holds up, such a hunting style would reinforce a debated hypothesis that powered flight evolved multiple times among dinosaurs, a feat once attributed solely to birds.

Toe pads are bundles of scale-covered flesh on the undersides of dinosaur feet, similar to “toe beans” on dogs and cats. Because the pads are points where the living animal interacted with surfaces, toe pads give paleontologists a “sense of where the rubber meets the road,” says Alexander Dececchi, a paleontologist at Mount Marty University in Yankton, S.D., who was not involved in the new study.

These contact points can paint a clearer picture of an animal’s behavior by providing “details that the skeleton itself wouldn’t show,” says Thomas Holtz Jr., a dinosaur paleobiologist at the University of Maryland in College Park, who was also not involved in the study.

To investigate dinosaur toe pads, Pittman and colleagues turned to the Shandong Tianyu Museum of Nature in Linyi, China. It “has arguably the largest collection of feathered dinosaurs in the world, and, importantly, they haven’t been prepared extensively,” Pittman says. Many of these dinosaur skeletons are still surrounded by rock, which is where soft tissues can be preserved. Such a specimen “gives us the best chance of finding this wonderful soft tissue information,” he says.
Using special lasers that cause the otherwise nearly invisible soft tissue in the fossils to fluoresce, the team found 12 specimens with exceptionally well-preserved toe pads among the thousands examined (SN: 3/20/17).

The team compared the fossil toe pads with those of 36 types of modern birds, whose toe pads vary with their lifestyle. Predatory birds, for example, have protruding toe pads with spiky scales for grasping prey, while ground birds that spend their time walking and running have flatter toe pads. The analysis showed that Microraptor’s toe pads and other aspects of the feet, like the shape of the toe joints and claws, are most like those of modern hawks. That similarity suggests that the dinosaur could hunt prey midair and on the ground like hawks do, the team says.

Other dinosaurs, like the feathered Anchiornis, had flatter toe pads and straighter claws, suggesting a terrestrial lifestyle. That’s in line with ideas about this dinosaur being a poor flier, Pittman says.
The idea that Microraptor hunted like a hawk is consistent with other fossil evidence. One Microraptor fossil has been found with a bird in its stomach, and Microraptor‘s skeletal and soft tissue anatomy suggest some powered flight capability.

There’s still more work to do to figure out how well the dinosaur may have flown. “Microraptor is not a bird, but a close relative. Just because it has feet like a predatory bird doesn’t necessarily mean it must be catching prey in the exact same way,” Pittman says. But Microraptor’s hawklike lifestyle “is a strong possibility,” he adds.
Flight could have been useful to Microraptor when hunting, even if it couldn’t stack up to today’s fliers. Dececchi speculates that Microraptor’s anatomy probably prevented it from outflying birds, but may have helped it surprise otherwise out-of-reach prey, including flying and gliding animals.

“You only have to be fast or aerobatic enough to catch other things in your environment,” Holtz says. “So, it’s not improbable that [Microraptor was] catching things in the air on occasion.”

Other paleontologists are more skeptical that Microraptor hunted on the wing. “It would be a bit of a stretch to me to suggest that Microraptor was pursuing prey in an aerial context,” says Albert Chen, a paleobiologist at the University of Cambridge. The new findings inform only “what the foot was used for.”

Alternative hypotheses, such as a completely or partially terrestrial hunting style, could fit the data too, Holtz says, but the “feet are definitely playing a major role in their prey capture,” whether on the ground or in the air.

For now, the picture of Microraptor’s ecology remains fuzzy, but as lasers continue to increase the picture’s resolution, our understanding of dinosaur flight may reach new heights.

Tanklike armored dinosaurs probably pummeled each other — not just predators — with huge, bony knobs attached to the ends of their tails. Thanks to new fossil findings, researchers are getting a clearer understanding of how these rugged plant eaters may have used their wicked weaponry.

Many dinosaurs known as ankylosaurids sported a heavy, potentially microwave-sized tail club. This natural sledgehammer has long been considered by both scientists and artists as a defensive weapon against predators, says Victoria Arbour, a paleontologist at the Royal British Columbia Museum in Victoria, Canada.

Fossil evidence for tail clubs’ targets was largely lacking, until Arbour and her colleagues chipped more rock away from the same skeleton they used to describe a new armored dinosaur, Zuul crurivastator, in 2017 (SN: 6/12/17).

The dinosaur had five broken spikes on its sides. The team’s statistical analyses showed the damaged spikes clustered in specific regions of the body. If a large carnivorous dinosaur made these injuries, says Arbour, they’d likely be more randomly distributed and include bite and scratch marks.
Instead, the injuries are more consistent with clubbing, the researchers report December 7 in Biology Letters.

Armored dinosaurs’ tail clubs start out either absent or too tiny to mount a major defense, and they get proportionally larger with age. Similar growth patterns occur in some modern animal weaponry like antlers. It’s possible that tanklike dinosaurs sparred with each other for mates, food or territory much like male deer and giraffes do today.

And that tail could also be useful in a pinch. “Having a tail club you can swing around at the ankles of a two-legged predator is a pretty effective weapon,” says Arbour.

“Ankylosaurs are often portrayed as stupid, loner dinosaurs,” she adds. The findings “show that they probably had much more complex behaviors than we give them credit for.”

Books about the pandemic. Books about the ancient past. Books about outer space. These were a few of Science News staff’s favorite reads. If your favorite didn’t make this year’s cut, let us know what we missed at feedback@sciencenews.org.

Vagina Obscura
Rachel E. Gross
W.W. Norton & Co.
$30

For centuries, scientists (mostly males) have ignored female biology, and women’s health has suffered. But researchers are finally paying attention, as Gross explains in this fascinating tour of what little is known about female anatomy (SN: 4/9/22, p. 29).

The Song of the Cell
Siddhartha Mukherjee
Scribner
$32.50

Patient stories and conversations with scientific luminaries enliven this tale of cell biology’s past, present and future, and how advances in the field have reshaped medicine (SN: 11/5/22, p. 28).

Breathless
David Quammen
Simon & Schuster
$29.99

In this portrait of the coronavirus and the scientists who study it, Quammen investigates some of the most pressing questions about the pandemic, including whether or not the coronavirus could have accidentally escaped from a lab (SN: 9/24/22, p. 28).

Virology
Joseph Osmundson
W.W. Norton & Co.
$16.95

This wide-ranging collection of essays is a meditation on society’s complicated relationship with viruses. In pondering SARS-CoV-2, HIV and more, Osmundson calls for more equitable access to medical care (SN: 7/16/22 & 7/30/22, p. 36).

The Milky Way
Moiya McTier
Grand Central Publishing
$27

This absorbing “autobiography,” written from the perspective of the Milky Way (a very sassy Milky Way), draws on mythology and astronomy to persuade readers that our home galaxy deserves respect and admiration (SN: 9/10/22, p. 28).

A Portrait of the Scientist as a Young Woman
Lindy Elkins-Tanton
William Morrow
$29.99

In this moving memoir, Elkins-Tanton recounts her journey to becoming a planetary scientist and leader of a NASA asteroid mission. Her struggles with childhood trauma and sexism in her career lay bare the barriers that many women in science still face (SN: 8/13/22, p. 26).

An Immense World
Ed Yong
Random House
$30

So much of the world is beyond the grasp of human perception, but this safari through animal senses helps readers imagine what we’re missing (SN: 7/16/22 & 7/30/22, p. 36).

How Far the Light Reaches
Sabrina Imbler
Little, Brown, & Co.
$27

By drawing parallels between their own life and the stories of bobbit worms, octopuses, sperm whales and other deep-sea dwellers, Imbler muses on such weighty themes as adaptation, survival and sexuality.

The Last Days of the Dinosaurs
Riley Black
St. Martin’s Press
$28.99

The basic story of the downfall of nonbird dinosaurs is familiar: They were killed off by an asteroid that slammed into Earth 66 million years ago. Using the most up-to-date science, Black fleshes out this tale, painting a vivid portrait of life before and after this apocalypse (SN: 4/23/22, p. 28).

The Rise and Reign of the Mammals
Steve Brusatte
Mariner Books
$29.99

The perfect follow-up to Black’s book on how the Age of Dinosaurs ended is this sweeping history of how the Age of Mammals began. Brusatte traces the origins of the evolutionary innovations that have made mammals so successful (SN: 6/18/22, p. 28).

Origin
Jennifer Raff
Twelve
$30

Exactly how and when humans first came to the Americas is still unsettled science. But Raff gathers archaeological and genetic evidence to piece together a convincing scenario. She also points out past mistreatment of Indigenous communities by geneticists and calls on researchers to do better and foster more collaborations (SN: 2/12/22, p. 29).

Pests
Bethany Brookshire
Ecco
$28.99

So-called pests are a human invention, argues Brookshire, a former staff writer for Science News for Students (now Science News Explores). In coming face to face with rats, feral cats, pythons and even elephants, Brookshire teases out the various social factors that cause people to deem certain animals a nuisance (SN: 12/3/22, p. 26).

A parasite might be driving some wolves to lead or go solo.

Wolves in Yellowstone National Park infected with Toxoplasma gondii make more daring decisions than their uninfected counterparts, researchers report November 24 in Communications Biology. The wolves’ enhanced risk-taking means they are more likely to leave their pack, or become leaders of their own.

“Those are two decisions that can really benefit wolves, or could cause wolves to die,” says Connor Meyer, a field biologist at the University of Montana in Missoula. The findings reveal a parasite’s potent ability to influence a wolf’s social fate.

Disease is often considered important for wildlife, mostly in the context of killing its host, Meyer says. “We have evidence now that just being infected with a certain parasite — Toxoplasma — can have pretty major implications for wolf behavior.”
Single-celled T. gondii has a track record of altering animal behavior. Its most important hosts are cats, which provide a breeding ground for the parasite in their small intestine. The parasite offspring hitch a ride on feline feces. Other animals then ingest the parasite, which then manipulates its new hosts’ behavior by tweaking certain hormones, making the hosts bolder or more aggressive. Infected mice, for example, can fatally lose their fear of cats, allowing the parasite to infect more hosts once the mice are consumed (SN: 1/14/20).

In Yellowstone National Park, many wolves are also infected with T. gondii, recent research has shown. So Meyer and colleagues wondered if gray wolves (Canis lupus) in the park showed any parasite mind-bending of their own.
Wolves were reintroduced to Yellowstone in 1995. Ongoing study of the park’s packs meant that the researchers had access to about 26 years’ worth of blood samples, behavioral observations and movement data for 229 of the park’s wolves.

The team screened the wolf blood for antibodies against T. gondii parasites, which reveal an infection. The researchers also noted which wolves left their pack — usually a family unit consisting of a breeding pair and their offspring — or became a pack leader.

Both are high-stakes moves for a wolf, Meyer says.

Infected wolves were 11 times as likely as noninfected wolves to disperse from their pack, the team found, and about 46 times as likely to eventually become leaders. The findings fit in with T. gondii’s apparent ability to boost boldness across a wide range of warm-blooded life.
The study fills a crucial gap in the Toxoplasma pool of knowledge, says Ajai Vyas, a neurobiologist at Nanyang Technological University in Singapore, who was not involved with the study.

“Most of the earlier work has been done in the lab,” Vyas says. But there are limitations to that approach, especially for re-creating how animals experience the effects of the parasite in their natural environment. Such research has “become almost like studying whale swimming behavior in backyard pools; [it] does not work very well.”

Wolves’ enhanced boldness may even form a feedback loop, the team proposes. The researchers found that not only do cougars (Puma concolor) in the park carry the parasite, but wolves’ infection rates were highest when the animals’ ranges overlapped with the park’s densest aggregations of cougars. Infected wolf leaders may be more likely to bring pack members into riskier situations, including approaching cougar territories, making additional infections more likely.

The feedback-loop idea is “very fascinating,” but more research is needed to confirm it, says Greg Milne, an epidemiologist at the Royal Veterinary College in London, who was not involved with the study. Such research may involve determining if infected wolves are more likely to migrate into an area with more cougars.

“I think people are just starting to really appreciate that personality differences in animals are a major consideration in behavior,” says study coauthor Kira Cassidy, a wildlife biologist at the Yellowstone Wolf Project in Bozeman, Mont. “Now we add a parasite-impacting behavior to the list.”

Next, the team is interested in examining the long-term consequences of a T. gondii infection, and whether infected wolves make better leaders or dispersers than uninfected wolves.

It’s also not known how infection impacts survival and reproduction rates, Cassidy says. “Infection may very well be detrimental in some ways and advantageous in others.”

As we head into our third pandemic winter, most people are all too familiar with the signs of COVID-19. The disease wears many different faces and can show up as chills, cough, difficulty breathing or other troublesome jumbles of symptoms. But sometimes, this illness can look positively peculiar.

On rare occasions, SARS-CoV-2 rears its head in body parts not typically touched by respiratory viruses. From head to COVID toe, doctors have seen a bevy of bizarre cases. Patchy tongues, puffy digits, hair loss — such issues can be worrisome for patients, says Peter Chin-Hong, an infectious diseases physician at the University of California, San Francisco.

But the outlook doesn’t have to be. That’s because such symptoms can end up going away on their own, says Chin-Hong, who has treated hundreds of people with COVID-19.

No one knows exactly how often COVID tongue, COVID toe, COVID eye or other rare conditions occur — and it’s not always clear that COVID-19 is the actual culprit. Still, the sheer scale of coronavirus infections means that SARS-CoV-2 has had many chances to show its stuff (SN: 9/8/22). The United States is now closing in on 98 million confirmed cases. Such a staggering case count means that “statistically speaking, you’re going to find people with more and more weird things,” Chin-Hong says.
Doctors rely on medical case reports for leads on potential treatments and hints about how long symptoms may last. Even just knowing that someone else has had splotchy mouth sores or tender toes can be helpful, Chin-Hong says. That lets him tell his patients, “You’re not the only one,” he says. “That means a lot to a lot of people.”

Internal medicine doctor Saira Chaughtai published one such study in October in the Journal of Medical Case Reports after one of her primary care patients came in with a symptom Chaughtai had never seen. Ten days after testing positive for COVID-19, the patient’s tongue began to swell, eventually erupting in white-ringed lesions.

Certain spots looked “denuded,” says Chaughtai, of Hackensack Meridian Health in Neptune, N.J. It was as if some of the tongue’s surface bumps had been sandpapered away. The patient wasn’t someone doctors would typically consider vulnerable, either. She was 30 years old, fit and healthy.

“I was like, ‘Oh my god, COVID can do anything,’” Chaughtai remembers thinking.
Oral sores can look different among patients. Chin-Hong has seen people with tongues coated white, as if they’d chewed a mouthful of tortilla chips. For Chaughtai’s patient, COVID tongue felt sensitive and irritated, with flare-ups that burned. Chaughtai wasn’t sure how to treat it.

She searched the scientific literature and prescribed an assortment of mouthwashes, which helped. But six months in, the patient’s tongue hadn’t fully healed. So Chaughtai got creative. She teamed up with a sports medicine doctor, who beamed low-level laser light at the patient’s tongue. He had previously used this photobiomodulation therapy to treat muscle injuries.

Laser light therapy makes blood vessels dilate, enhancing blood flow to treated areas, which could promote healing, Chaughtai says. It seemed to work for her patient. The tongue lesions began to heal and flare-ups subsided. The woman still occasionally feels some tongue sensitivity when stressed, but never as bad as her initial outbreak.

The effects of COVID toe
About 1,300 kilometers west, a podiatrist in Crown Point, Ind., also dilated a patient’s blood vessels to treat a curious coronavirus condition: COVID toe. After infection with SARS-CoV-2, patients’ fingers and toes can plump up, sometimes painfully, and turn pink or reddish purple.

“We were seeing cases of these lesions that look like chilblains, which is something you get when you’re exposed to cold weather,” says Michael Nirenberg of Friendly Foot Care. But his patients hadn’t been in the cold — they’d been exposed to the coronavirus.

Nirenberg has seen as many as 40 people with the symptom, which he’s found tends to clear up in a month or two. But one of his patients, a 59-year-old man, just couldn’t kick COVID toe. It ultimately lingered for nearly 670 days — the longest documented case Nirenberg has seen. “The term we used was long COVID toe,” he says. Nirenberg and colleagues reported the case this spring in the Journal of Cutaneous Pathology.
Nirenberg prescribed daily application of a nitroglycerin ointment to boost blood flow to the toes. That may have helped, Nirenberg says, “but I don’t know if time also did the trick.” After 22 months, the condition may have finally resolved on its own.

The number of COVID toes Nirenberg encounters these days has gone down, but he’s still seeing people come in with the condition. And though Chaughtai has not treated another case of COVID tongue, a man recently e-mailed her saying that he had suffered from a similar affliction for two years.

UCSF’s Chin-Hong says he thinks it’s important for people to know that COVID-19 can cause such a variety of symptoms (SN: 11/11/22). “We can’t really predict who’s going to get what,” he says. But in his experience, strange symptoms have tended to crop up more often in people who haven’t been vaccinated.

Such symptoms may not be as serious as COVID-affected hearts or lungs, but they can certainly look scary, Chin-Hong says. “If this is a reason why some people might get vaccinated,” he says, “I think that would be great.”

If you saw Carlos Argüelles-Delgado’s childhood bedroom — the whiteboard for working out problems, the math textbooks they asked for as birthday gifts — you’d likely not be surprised that this kid would grow up to push the boundaries of modern physics.

For years, physicists have known that the most successful theory to describe what the universe is made of, called the standard model, is broken. By prying at one of the biggest cracks in the framework — neutrinos — Argüelles aims to discover what’s next for the field.

Neutrinos are mysterious even for subatomic particles. They’re hard to study because they barely interact with matter, and what scientists do know about them is baffling — like the fact that neutrinos have mass when the standard model predicts they shouldn’t. “That’s why I like neutrinos,” Argüelles says. “They misbehave.”

Many scientists think this confusing behavior is a sign that neutrinos are affected by undiscovered particles. In that case, demystifying neutrinos could open a new window on the universe. The question is: Who are these hidden partners, and how can scientists find them?
Standout research
To search for answers, Argüelles often relies on data from the IceCube Neutrino Observatory in Antarctica. IceCube’s thousands of buried detectors spot neutrinos from the faint flashes of light they leave after interacting with ice.

For their Ph.D., Argüelles combed through these signals to look for “sterile” neutrinos. If this breed of neutrinos exists, they would interact with matter even less than normal neutrinos do. Sterile neutrinos could explain several troubling problems with the standard model, like why neutrinos have mass and why antimatter is rarer than matter. Sterile neutrinos are also a candidate for dark matter, the unidentified substance that outweighs normal matter in the universe.

The search made for a huge project, but Argüelles finished it in about half of the time typical for U.S. Ph.D.s in the physical sciences. And though they found no signs of the would-be particle, Argüelles ruled out some ideas about what it could be like.
“It was an amazing performance,” says neutrino physicist Francis Halzen, who advised Argüelles’ Ph.D. work at the University of Wisconsin–Madison and is IceCube’s head scientist. “It was a piece of art.”

Argüelles also looks for other possible hidden particles, like WIMPs, a hypothetical particle that could be a form of dark matter. And Argüelles isn’t afraid to pursue research farther from their specialty. Though no expert in quantum computers, for example, Argüelles was the first to use a quantum computer to simulate how neutrinos can change from one type to another. That could one day help scientists better understand neutrino-rich events like supernova explosions.

“I just hate when people tell me I cannot do something,” Argüelles says.

Halzen describes Argüelles as fearless, the kind of scientist who is never afraid to ask questions. “I don’t think they have any regard for their reputation, ever,” he says.
Backstory
Argüelles’ attitude toward research is, in part, forged by past struggles to overcome hardship and discrimination.

“There are worse things in life than not being able to solve a problem,” they say.

Growing up in Peru meant building a life on shifting ground. The economy was unstable, and at times Argüelles’ family struggled to make ends meet.

Though Argüelles’ parents were supportive and saw knowledge as a safe investment, they at first rejected Argüelles’ desire to study physics. Argüelles, wiping a tear from their eye, recalls their father saying, “You’re just going to die of hunger.” Soon Argüelles’ parents did embrace the career choice.

Argüelles says Peru, when they were growing up, was also an “extremely negative environment” for LGBTQ+ people. “I’m a gay man,” they say, “and it was very, very, very difficult.”

Same-sex marriages are not recognized in Peru. Hate crimes and discrimination based on sexual orientation were only prohibited in 2017, by a presidential decree that the country’s Congress tried but failed to overturn.

When Argüelles left Peru in 2012 to pursue their Ph.D., they found that studying physics in the United States wasn’t without obstacles. Almost nobody high up in the field looked like them. They struggled under the weight of expectations and felt that voicing their anxieties would get them branded as weak. But with help from mentors, Argüelles persevered.

Now, as an assistant professor at Harvard, Argüelles sees their students — particularly women and Hispanics — facing the same challenges. Argüelles is passionate about supporting them.

“It’s about not giving up, right?” Argüelles says. “I still go through some of these things myself. But I’ll survive it.”

Visitors to the village of Drumnadrochit, on the western shore of Scotland’s murky Loch Ness, come to see the nearby ruins of Urquhart Castle or to chance a glimpse of the elusive Loch Ness Monster. But growing up in Drumnadrochit, planetary scientist Robin Wordsworth says it was the unobscured view of the cosmos that seized his attention. “There are incredibly clear skies up there,” he says.

Today, Wordsworth lives on the other side of the Atlantic. He’s a researcher and professor at Harvard University. But his gaze is still set on the solar system and beyond. From studying how rocky planets may occasionally become encased in glaciers to exploring the sizes of alien raindrops or the details of how humans might one day settle Mars, Wordsworth’s scientific explorations vary widely. His research group tends to “do a lot of different things at once,” he says. “If I was to summarize it in a sentence, it would be to understand what drives habitability on planets through time.”

Standout research
Wordsworth defines a planet’s habitability as its ability to support life. The idea that life could survive elsewhere in the cosmos has always fascinated Wordsworth, a science fiction fan. Apart from Earth, astronomers have discovered roughly 20 potentially habitable worlds in the universe. With data collected by ground-based observatories, satellites and rovers, he uses supercomputers to construct simulations of planets and the evolution of their climates. Climate is a big focus because it determines whether a planet’s surface can harbor liquid water — a necessity for all known forms of life.
Wordsworth’s most notable research reconstructs the climate of early Mars. Martian river valleys and other geologic clues suggest that abundant liquid water once flowed across the Red Planet, and the early Martian climate has thus become a hot topic for scientists seeking signs of alien life. But for decades, the best researchers could do was build one-dimensional models that struggled to replicate key atmospheric components, such as clouds.

In 2013 while at the Laboratory of Dynamic Meteorology in Paris, Wordsworth and colleagues presented a 3-D model of the early Martian climate, with clouds and an atmosphere containing large amounts of carbon dioxide. Those are key components for studying how the early Martian atmosphere may have reflected and trapped heat, says astrobiologist James Kasting of Penn State.

Wordsworth was the one who figured out how to incorporate clouds into the model, thanks to his strong programming skills, handle over mathematics and determination, Kasting says. “He’s been publishing the best climate calculations for early Mars. There’s really nobody else who is in his lane.”
What’s next
Wordsworth’s otherworldly reconstructions may help us better understand whether life might have emerged on Mars or elsewhere. Another strand of his research could help humans one day settle the Red Planet.

Today, most of Mars’ surface is too cold to sustain liquid water, and the planet’s thin atmosphere offers little protection from the sun’s intense ultraviolet radiation. These conditions make it inhospitable to would-be Martian settlers. But in a 2019 study, Wordsworth and colleagues proposed that sheets of insulating silica aerogel deployed over ice-covered areas might make survival possible.

In lab tests, layers of aerogel just centimeters thick filtered out 60 percent of UVA and UVB radiation and almost all of the more dangerous UVC rays, while permitting enough light through for photosynthesis. What’s more, the shields warmed the air underneath by more than 50 degrees Celsius, which could make liquid water and growing crops possible. Looking ahead, Wordsworth plans to investigate how settlers on Mars might use bioplastics or other renewable materials to become self-sustaining.

And far beyond the Red Planet, the exoplanets await. “The James Webb Space Telescope has just begun to collect new exoplanet data,” Wordsworth says. Observations of their atmospheres will help researchers test ideas about how these distant planets and their climates evolve, he says. “It’s just an incredibly exciting time.”