A new peek at the genetics of beetle genitals reveals the underpinnings of a battle of the sexes.
When mating, males of Japan’s flightless Carabus beetles insert a chitin-covered appendage that, once inside a female, pops out a plump sperm-delivery tube as well as a side projection called a copulatory piece. That piece doesn’t deliver any sperm, but steadies the alignment by fitting just so into a special pocket inside the female reproductive tract.
Researchers in Japan have now identified several regions of DNA that include genes controlling the length and width of the piece and pocket. Instead of being controlled mostly by the same genes, the beetles seem to have a fair amount of genetic freedom in changing one sex’s doodad dimensions without also resizing the other sex’s counterpart, evolutionary ecologist Teiji Sota of Kyoto University and colleagues say June 26 in Science Advances. Within a given species of these beetles, males and females have evolved compatible sizes, but the capacity for mismatching shows up in hybrids. Out-of-sync sizes can cause ruptures, snap-offs and generally low numbers of offspring. This misfortune matters not just to a few unlucky beetles, but to the whole process of forming species, or speciation.
“I personally think that one of the greatest remaining mysteries in evolutionary biology is the role of genital evolution in speciation,” says Justa Heinen-Kay of the University of Minnesota in St. Paul. She was not part of the beetle work, but has studied fish genital evolution. Across the animal kingdom, shapes of genitals are among the most rapidly evolving traits, she points out. There are species that otherwise look almost exactly alike that specialists distinguish by differences in genitals.
One early idea linking genital shape with the formation of species proposed that developing a unique his-and-hers fit worked as a lock and key that separated members of one species from another. One of Sota’s early papers, in 1998, proposed that the genital quirks of the ground beetles worked as just this kind of separator of species. The lock-and-key concept sounded great, says Brian Langerhans of North Carolina State University in Raleigh. But disputes over evidence of the process led “to many believing it played little role in reality.” Recently though, he says, the idea is rousing interest again.
Sota has started exploring the genetics governing size in the ground beetles’ proposed locks and keys. Earlier research had suggested a battle of the sexes over genital size. Longer could be better for a male, as it may help outcompete a less-endowed guy in the struggle to fertilize a female’s egg. Yet longer male parts can damage females, unless a female’s parts lengthen, too. Biologists have proposed that certain traits, for instance the sizes of his and her organs, stay in sync in a species because the same genes influence both the male and female form. Appealing as that idea might sound, in this case, the beetle researchers are now arguing against it.
The evidence comes from analyzing the odd genital forms in hybrids of two beetle species that manage to mate. The patterns of variety in the offsprings’ genital width and length suggest that genes for female pocket width are not tied to male piece width, and are only loosely related to male length. The females thus have some freedom genetically to vary on their own. What’s keeping male and female parts in sync for the beetles, Sota suggests, is not shared genes but shared consequences. Parents with the wrong-sized genitals just don’t have a lot of offspring.
Over 100 hours of scanning has yielded a 3-D picture of the whole human brain that’s more detailed than ever before. The new view, enabled by a powerful MRI, has the resolution potentially to spot objects that are smaller than 0.1 millimeters wide.
“We haven’t seen an entire brain like this,” says electrical engineer Priti Balchandani of the Icahn School of Medicine at Mount Sinai in New York City, who was not involved in the study. “It’s definitely unprecedented.”
The scan shows brain structures such as the amygdala in vivid detail, a picture that might lead to a deeper understanding of how subtle changes in anatomy could relate to disorders such as post-traumatic stress disorder.
To get this new look, researchers at Massachusetts General Hospital in Boston and elsewhere studied a brain from a 58-year-old woman who died of viral pneumonia. Her donated brain, presumed to be healthy, was preserved and stored for nearly three years. Before the scan began, researchers built a custom spheroid case of urethane that held the brain still and allowed interfering air bubbles to escape. Sturdily encased, the brain then went into a powerful MRI machine called a 7 Tesla, or 7T, and stayed there for almost five days of scanning.
The strength of the 7T, the length of the scanning time and the fact that the brain was perfectly still led to the high-resolution images, which are described May 31 at bioRxiv.org. Associated videos of the brain, as well as the underlying dataset, are publicly available. Researchers can’t get the same kind of resolution on brains of living people. For starters, people couldn’t tolerate a 100-hour scan. And even tiny movements, such as those that come from breathing and blood flow, would blur the images.
But pushing the technology further in postmortem samples “gives us an idea of what’s possible,” Balchandani says. The U.S. Food and Drug Administration approved the first 7T scanner for clinical imaging in 2017, and large medical centers are increasingly using them to diagnose and study illnesses.
These detailed brain images could hold clues for researchers trying to pinpoint hard-to-see brain abnormalities involved in disorders such as comas and psychiatric conditions such as depression. The images “have the potential to advance understanding of human brain anatomy in health and disease,” the authors write.
Divers monitoring coral reefs off St. Thomas in the U.S. Virgin Islands in January noticed something alarming: Big white lesions were eating into the colorful tissues of hundreds of stony corals. Some corals were dead by the next day — only their stark white skeletons remained. Others languished for up to two weeks. Within four months, more than half of the reef suffered the same demise.
What’s killing the corals is far from clear, but the prime suspect is stony coral tissue loss disease, sometimes referred to by its initials SCTLD or by the nickname “skittle-D.” This infection, discovered off Florida in 2014, is responsible for what some scientists consider one of the deadliest coral disease outbreaks on record. In the Caribbean, the disease is now ravaging about a third of the region’s 65 reef-building species, scientists estimate. Yet researchers aren’t even sure if the disease is viral, bacterial or some other microbial mix. Whatever the cause, “it’s annihilating whole species,” says coral ecologist Marilyn Brandt, who is leading a science team trying to tackle the outbreak from multiple research angles.
Past outbreaks of other coral diseases near St. Thomas have cut coral cover by up to 50 percent over a year, says Brandt, of the University of the Virgin Islands. But this new disease has done the same amount of damage in half that time — spreading faster and killing more corals than any past outbreaks in the area.
“It marches along the reef and rarely leaves corals behind,” Brandt says. “We’re pretty scared.” Coral reefs occupy less than 2 percent of the ocean floor. But they play a crucial role in the ecosystem, sustaining an estimated quarter of marine species. Sometimes mistaken for rocks or plants, corals are actually collectives of coral polyps, tiny invertebrates that get sick just like any other animal. Corals sometimes succumb to deadly plagues. Other times, they can shake off milder maladies akin to a common cold.
Since the first coral disease was documented in the 1970s in the Caribbean, researchers have identified dozens more around the world, with the Caribbean now considered a coral disease hot spot. But scientists still know little about these illnesses and how they work. Many marine microbes don’t grow well in petri dishes and test tubes, so studying coral diseases is tough, Brandt says.
Even the names given to the diseases are vague, based only on the visual cues of an infection, such as yellow-band disease, dark-spot syndrome and white plague. And it doesn’t help that many look similar. Stony coral tissue loss disease, which first attacks brain corals before moving on to other stony corals, was initially mistaken for white plague.
Performing reef triage Off southeast Florida, the outbreak has persisted for five years. In that time, the disease has affected almost all of a 580-kilometer stretch of reef, including the Florida Keys, says marine biologist Karen Neely of Nova Southeastern University in Fort Lauderdale, Fla. Such a prolonged assault surprised scientists. Coral disease outbreaks typically burn out after a few months. Neely and others are trying to save Florida’s reef-building corals by moving hundreds of healthy colonies to tanks, where they can be studied, bred and protected from the outbreak along the coast. Meanwhile, divers slather sick corals left in the reef with a disinfectant and an amoxicillin paste, which seems to heal lesions. Neely estimates that Florida researchers have treated nearly 1,200 colonies since January.
With the antibiotic, “we are seeing about 85 percent success,” Neely says. But the medicine doesn’t stop new lesions from popping up. “One of the big priorities is to develop colony level treatments,” she says. Until then, this paste “is the best we can hope for.”
The antibiotic’s effectiveness suggests the disease could be bacterial, Brandt says. But the disease could have viral origins, in which case the paste would be treating a symptom, not the cause. Since the St. Thomas outbreak is just getting started, Brandt’s team is trying a different approach to halt the disease: removing sick corals and leaving the healthy ones behind. That should reduce the water’s pathogen load, which in theory makes it more difficult for the disease to spread, she says. But it will take about six months before the results of this stopgap strategy are clear. Hunting a coral killer To find out what might be causing the disease, members of Brandt’s team are looking at corals’ microbiomes — the multitudes of microbes that live in and around corals. Building the list of suspects requires first sorting out what normally belongs on healthy corals, and what doesn’t.
At Woods Hole Oceanographic Institution in Massachusetts, marine ecologist Amy Apprill and colleagues are scrutinizing the microbiomes of sick corals, as well as sediments and water circulating around the reefs in St. Thomas. Comparing that data with data from Florida corals may uncover similarities between the two outbreaks that can help narrow the list of culprits, Apprill says.
The team is also focusing its microscopes on samples of brain and star corals taken just as lesions popped up. Originally from a healthy reef in St. Thomas, the corals caught the disease during an experiment in which they were placed near infected corals from Flat Cay in an aquarium. “We might be getting a look at what ‘early’ disease looks like,” Apprill says, before opportunistic microbes gain a foothold.
She doesn’t expect to find a singular pathogen, though. “Many scientists are moving toward this idea that it may be a consortium” of microbes that causes a disease, she says. And that consortium could look different for different coral species and in different environments. But a disease might trigger similar shifts in microbial diversity, so those patterns are something to watch for, Apprill says.
New clues about stony coral tissue loss disease are coming from a research team in Florida led by Julie Meyer of the University of Florida in Gainesville. That team found that diseased corals had microbiomes that were more prone to change and become more diverse than their healthy counterparts. Genetic analyses of these microbiomes identified five types of bacteria abundant in corals infected with the disease, the researchers report May 3 at bioRxiv.org. At least one type thrives in low-oxygen conditions that accompany decaying tissue, and all have been linked to other coral disease outbreaks around the world.
But more work is needed to determine if the microbes identified are causing the disease, or simply taking advantage of an opportunity to populate the weakened coral.
Profiling the victims While some researchers hunt for pathogen suspects, coral immunologist Laura Mydlarz and others are investigating what happens to sickened corals at the cellular level. “I’m more on the host side,” trying to figure out why some hard coral species are more vulnerable than others, says Mydlarz, who is part of Brandt’s team.
Mydlarz’s lab, at the University of Texas at Arlington, has shown that the immune systems of some susceptible coral species get stuck in cell-death mode, or apoptosis, when tricked into thinking that pathogenic bacteria are invading. These corals slough off their tissue. Species that are more disease-tolerant, however, had immune systems that went into cell-recycling mode and fought off infection, her team reported in Proceedings of the Royal Society B in 2017.
Mydlarz suspects something similar might be happening in corals vulnerable to stony coral tissue loss disease. That’s because the species in her study that favored cell-death mode are among those hit hardest by the outbreak. Waters getting warmer This race to learn more about stony coral tissue loss disease and other infections is becoming urgent as climate change warms ocean waters. Global warming is like a one-two punch for coral disease: Heat stress and bleaching may weaken coral defenses, while warming waters send pathogens into overdrive. Pollution, overfishing and other environmental factors can also stress corals, giving pathogens an in.
“Coral reefs just can’t catch a break,” Brandt says. “I feel like we’re playing whack-a-mole,” addressing one challenge after another.
Oceans are now warming 40 percent faster than what had been predicted in the 2014 report by the U.N. Intergovernmental Panel on Climate Change, according to an analysis published in January in Science. And the trend is expected to continue, as oceans soak up roughly 93 percent of excess atmospheric heat trapped by greenhouse gases.
As ocean temperatures rise, coral disease will likely rival bleaching as a major driver of coral decline. Disease outbreaks are expected to become more frequent and more severe, researchers reported in 2015 in Nature Climate Change.
Flat Cay reef off St. Thomas had been considered resilient, having rebounded from a major bleaching event in 2005 and back-to-back hurricanes in 2017. But the current outbreak has killed off all of the reef’s maze corals, a type of brain coral. And pillar corals could be next, Brandt says. Stony coral tissue loss disease “seems to be capable of changing the face of coral reefs as we know it.”
A disease on the move The researchers are trying to keep up with where and how the disease is spreading. Pathogens may have made their way from Florida to St. Thomas in the ballast water of ships, says coral reef ecologist Dan Holstein of Louisiana State University in Baton Rouge. Stony coral tissue loss disease has also been reported on reefs off the east coast of Mexico, Jamaica, St. Maarten and the Dominican Republic.
Holstein is using ocean current data and other factors to forecast where the disease might show up next. Early results suggest that another U.S. Caribbean territory, Puerto Rico, should be worried. Divers in May confirmed that the outbreak is inching toward the Puerto Rican island of Vieques, with star corals about 17 kilometers offshore and 40 meters deep already pocked with white lesions, says Tyler Smith, who oversees the reef monitoring program at the University of the Virgin Islands in St. Thomas.
The discovery was disheartening, Smith says. Scientists knew that star corals in shallower waters were susceptible to the disease, but hoped those living in deeper waters might be spared (SN Online: 7/19/18). He likens the deep reefs, made up of hundreds of millions of densely packed colonies, to a powder keg. With deeper star corals also succumbing, “the spread of [the disease] might pick up very rapidly,” Smith says, “even more than it is now.”
Brandt and colleagues are continuing to monitor reefs in the U.S. Virgin Islands. In June, they found a glimmer of hope in waters near St. Croix. None of the 270 sites surveyed around the island showed signs of the disease, though some corals did have the less-severe white plague. “It was a moment of panic,” Brandt says. “Everybody is on high alert.”
From the beginning, the moon has been humankind’s perpetual nighttime companion.
Accompanied by innumerable points of light, the moon’s luminous disk hovered overhead like a dim substitute for the sun, just with a shape not so constant. Rather the moon waxed and waned, diminishing to a barely discernible sliver before disappearing and then gradually restoring itself to fullness.
It was obviously far away, yet sometimes — especially when on the horizon — seemed so near. Its size, its phases, its peculiar blemishes resembling a face, made the moon an enduring mystery for all ancient civilizations.
In virtually every culture throughout history, the moon acquired an elaborate mythology. For the Greeks the moon was the goddess Selene (or Artemis, or Phoebe); for the Romans, Luna or Diana; for the Chinese, Chang’e. For some other cultures — the Inuit peoples of the Arctic, for instance — the moon was a male deity. As astronomical objects go, the sun could certainly claim a more prominent impact on human affairs — illuminating darkness, providing warmth, nourishing the growth of vegetation essential to sustaining life. But the sun did its job out in the open, in (obviously) the light of day. The moon was more mysterious. Primitive skywatchers speculated about the source of its light, what it was made of and whether it was inhabited. It inspired wonder, and curiosity, and therefore played no small part in inspiring the origin of science itself.
As the story commonly goes, early Greek philosophers gave birth to science by seeking rational, logical explanations for natural phenomena in preference to mythological explanations — replacing mythos with logos. But as the historian Liba Taub has pointed out, Greek philosophy did not really dispose of mythos, but rather merged it with logos — or if not a merger, at least a juxtaposition. Mythos and logos could both in some context merely mean “story.” And so for the Greeks, mythos was not always opposed to logos, Taub wrote in her book Aetna and the Moon; “they were recognized forms of discourse that could, on occasion, both be invoked, and each could lay claim to the truth.” Philosophers such as Parmenides, Empedocles and Plato used mythlike narrative to convey essentially scientific ideas.
In no case was the mythos-logos juxtaposition more clearly in force than with the moon. In the first century, the Greek-Roman writer Plutarch’s On the Face which Appears on the Orb of the Moon explored via dialog Greek scientific opinions about the moon: the nature of eclipses, whether the moon shone on its own or reflected light from the sun, whether the moon was made of earthlike matter or celestial crystal. But the speakers in Plutarch’s dialog did not restrict themselves to scientific matters, also discussing the belief that the moon served as a receptacle for souls leaving earthly bodies upon death.
In Plutarch’s discussion, “science and myth are in dialogue,” Taub wrote. “Scientific enquiry and mythological explanation are not set up as rivals; rather, they are presented as two complementary aspects of a full consideration of nature.”
Even after the ascendancy of modern science, the moon retained its cultural and mythological presence, in literature and poetry, song and film. Full moons cause madness, or crime, or turn people into werewolves. Entertainers sing of dancing in the moonlight, a bad moon on the rise or being followed by a moonshadow. Frank Sinatra crooned “Fly Me to the Moon.” Cher was Moonstruck, and Jimmy Stewart declared his love for Donna Reed by offering to lasso the moon and bring it down to Earth. Humans have always been lunatics about the moon.
No wonder people have long imagined going there.
Among the earliest dreamers of a lunar voyage was Lucian of Samosata, a Syrian satirist born about A.D. 120. His Vera Historia (A True Story, “true” being the satirical part) recounts an ocean voyage gone wrong when a waterspout lifted Lucian’s boat into the sky, landing it (after seven days of flight) on the moon. Lucian and his companions found the moon full of various weird, huge forms of life, kind of like what you’d expect to find in the Forbidden Forest outside Hogwarts (a flea the size of a dozen elephants, for example). By some accounts, Lucian’s “true” story was the first true work of science fiction. But some sci-fi authorities reserve that honor for the prominent astronomer Johannes Kepler, whose Somnium (The Dream) was published in 1634, four years after Kepler’s death. Kepler did not imagine flying to the moon himself, but wrote of a dream in which a demon described the moon’s inhabitants to an Icelandic boy and his mother, a witch (not associated with Hogwarts).
After Kepler’s Somnium, moon voyages became a popular fascination with various writers, Cyrano de Bergerac and Daniel Defoe among them. In 1638, for instance, English historian and author Francis Godwin published a short novel called The Man in the Moone, telling of the adventures of a Spaniard named Domingo Gonsales. Gonsales managed to train a group of migratory swans to wear harnesses and fly him around in an “engine” he had devised. But unknown to Gonsales, the swans’ migration took them regularly to the moon. He described a 12-day journey watching the Earth recede from view as the swans delivered him to the lunar surface. There he encountered a utopian lunar society, with inhabitants extraordinarily tall, and with no illness, crime or need for any lawyers.
Around the same time another Englishman, the philosopher and clergyman John Wilkins, composed
A Discourse Concerning a New World and Another Planet, a fully scientific discussion of the moon and the possibility of voyaging there. Wilkins analyzed all the scientific questions about the moon and the possibility of its habitation, and seriously considered the prospect of visiting it. “Tis possible for some of our posterity, to find out a conveyance to this other world,” he wrote.
Wilkins argued that the air between Earth and moon might not be so cold and thin as some had supposed, and that future technology might permit humans to attain a height above the reach of Earth’s gravity. (Lack of gravity offered the additional advantage of requiring no expenditure of energy and hence no need for food during the journey.)
Possibly, Wilkins speculated, a human might achieve flight by attaching wings, or perhaps by riding on the back of a large bird. If neither of those two plans turned out to be feasible, Wilkins offered a third: “I do seriously, and upon good grounds, affirm it possible to make a flying chariot, in which a man may sit, and give such a motion unto it, as shall convey him through the air.” And Wilkins foresaw fame and fortune for such a chariot’s inventor: “The perfecting of such an invention, would be of such excellent use, that it were enough, not only to make a man famous, but the age also wherein he lives. For besides the strange discoveries that it might occasion in this other world, it would be also of inconceivable advantage for travelling, above any other conveyance that is now in use.”
For both Godwin and Wilkins, flying to the moon seemed feasible, as in those days nobody knew that the vacuum of space separated the top of the Earth’s atmosphere from the lunar surface. Only later in the 17th century, when experiments established the reality of a vacuum, and Isaac Newton’s laws specified the mechanical and gravitational impediments, did the dreams of moon visitation seem most likely unattainable.
But dreamers still dreamed. In 1827, one Joseph Atterley (pseudonym for George Tucker, a University of Virginia professor who had once been a U.S. congressman) wrote A Voyage to the Moon. Atterley traveled in a copper vessel powered by “lunarium,” an antigravitational metal (repelled by the Earth, but attracted to the moon) discovered in Burma. Later in the 19th century Jules Verne wrote the more famous From the Earth to the Moon, in which propulsion for the space capsule was provided by a powerful cannon.
All the while that the moon mesmerized songwriters and novelists, it provided similar inspiration for science. Lunar cycles and their importance for creating an accurate calendar were major aspects of ancient and medieval science, as was the moon’s role in eclipses, a foundational element in the development of astronomy. Isaac Newton, of course, made science truly modern following his realization that the moon was just like a falling apple, guided by gravity (only in the moon’s case, falling around the Earth instead of into it). And while showing how difficult it might be to overcome the Earth’s gravity and fly to the moon, Newton’s physics at the same time specified exactly the mechanical requirements to do so. Rocket technology for meeting those requirements, developed in the 20th century, produced the multistage Saturn V that launched Apollo astronauts Neil Armstrong, Buzz Aldrin and Michael Collins on their way to the moon half a century ago.
Perhaps it was that success in achieving John F. Kennedy’s vision, of landing a man on the moon and returning him safely to Earth, that most dramatically demonstrated the merger of myth with logos, of lunar science with the moon’s cultural relevance. Armstrong’s first small step reminded all humankind of its essential unity as a single community in the cosmos — the moon serving as symbol for all that every member of the human race has in common. After July 20, 1969, it became truer than ever what Jules Verne wrote in the opening pages of From the Earth to the Moon, when Impey Barbicane proposed such a voyage to the members of his club: “There is no one among you, my brave colleagues, who has not seen the Moon, or, at least, heard speak of it.”
The Hayabusa2 spacecraft has made its second and final attempt to grab a pinch of dust from asteroid Ryugu. At about 9:06 p.m. EDT on July 10, the Japanese spacecraft briefly touched down near an artificial crater it had previously blasted into the 4.5-billion-year-old asteroid’s surface. If the dust grab went well, it’s the first spacecraft to ever collect a sample from an asteroid’s insides.
“We’ve collected a part of the solar system’s history,” said project manager Yuichi Tsuda, of the Japanese Aerospace Exploration Agency, at a July 11 press conference. Hayabusa2 first successfully touched down on Ryugu’s surface on February 22, after months of experiments on Earth to make sure the spacecraft’s sample collection technique would work on the asteroid’s surprisingly rocky surface (SN Online: 2/22/19). The strategy involves firing a tantalum bullet at close range into the surface to kick up surface dust and then catching some of that dust in a long, flared horn (SN: 1/19/19, p. 20).
In April, the spacecraft dropped a two-kilogram copper cylinder from about 500 meters above the asteroid to blast an artificial crater about 10 meters wide and 2 meters deep into its surface (SN Online: 4/26/19), in preparation for the second sample retrieval. Its goal: to stir up buried material that hasn’t seen sunlight for up to billions of years.
“Touchdown is a high risk operation,” the team wrote on its website July 8 in preparation for the second sample retrieval. “Just because we have succeeded in the past does not mean we can easily do so again.”
The Japanese space agency decided to aim Hayabusa2 at an area about 20 meters north of the crater’s center, where it looks like dark material from inside the crater landed. After hours of descending toward the asteroid’s surface, Hayabusa2 briefly tapped the targeted spot and fired the bullet, creating a spray of pebbles. The spacecraft immediately started to rise again. At 9:51 p.m. EDT, mission control received word that the spacecraft was safe. “The state of the spacecraft is normal and the touchdown sequence was performed as scheduled,” the team tweeted. “Project Manager Tsuda has declared that the 2nd touchdown was a success!” Hayabusa2 will leave Ryugu in November or December, and is expected to arrive back at Earth in 2020. That’s when the team will confirm that the spacecraft successfully collected the dust. Studying material from the asteroid’s surface and subsurface will let scientists tease out details of the asteroid’s history and the early history of the solar system (SN: 4/13/19, p. 11).
There once was a little bird, smaller than a sparrow, that lived about 99 million years ago. And it had a freakishly long toe.
Researchers found the ancient bird’s right leg and foot preserved in a chunk of amber. Its third digit is 9.8 millimeters long, about 41 percent longer than its second-longest digit — and 20 percent longer than its entire lower leg. This foot morphology is unique among any known bird species, whether modern or Mesozoic, the team reports online July 11 in Current Biology. Although it’s not clear what purpose the extra-long toe served, the digit may have helped the bird find food in hard-to-reach places, such as through a hole in a tree. The team, led by paleontologist and frequent amber-fossil finder Lida Xing of the China University of Geosciences in Beijing, compared the toe size ratios of the fossilized bird with those of 20 other birds that lived during Mesozoic, the era that spans between 252 million and 66 million years ago, as well as with toe size ratios of 62 living species. Although some modern tree-dwelling birds do have elongated third digits, none of the other birds living or extinct have quite such a dramatic difference in toe sizes, the team found. Determining the bird to be a new species, the team named it Elektorornis chenguangi — using the prefix elektor, meaning amber in Greek, and suffix ornis, meaning bird; and with a nod to Chen Guang, the curator at the Hupoge Amber Museum in Tengchong City, China. E. chenguangi was a member of a group of toothed, clawed birds called enantiornithines that died out along with nonavian dinosaurs about 66 million years ago. Like most enantiornithines, the tiny E. chenguangi was probably a tree-dweller, and that lengthy digit may have helped the bird to grasp on to tree branches and limbs — in addition to possibly giving it a leg up in feeling around for food.
Editor’s note: The second caption in this story was updated July 17, 2019, to correct the comparison between E. chenguangi‘s longest and second-longest digits. The third digit is 41 percent longer than the second-longest digit, not twice as long.
Carlos Jared discovered the first known venomous frog by accident. And it took him a long time to connect his pain with tree frogs that head-butted his hand.
Jared, now at the Butantan Institute in São Paulo, got his first hint of true venom when collecting yellow-skinned frogs (Corythomantis greeningi) among cacti and scrubby trees in Brazil’s dry Caatinga region. For hours after grabbing the frogs, intense pain radiated up his arm for no obvious reason. He knew frogs have no fangs to deliver toxin. Many frog species can poison an animal that touches them, but they’re poisonous. True venomous animals actively deliver toxins.
Jared realized head-butting delivers venom only when he saw the frogs’ upper lips under a microscope. Bone spikes erupted near venom glands that looked “giant,” he says. As a frog’s lips curl back, glands dribble toxins onto spikes sticking out from the skull and the frog pokes them against foes.
Gram for gram, the frog venom is almost twice as dangerous to mammals as typical venom of the feared Bothrops pit vipers, Jared, Edmund Brodie Jr. of Utah State University in Logan and their colleagues report online August 6 in Current Biology. The researchers also report a second spiky-skulled venomous frog, Aparasphenodon brunoi, which is a forest species not very closely related to yellow-skinned frogs. It head-butts toxins 25 times as powerful as typical pit viper venom, a phenomenon luckily not discovered by handling.
Accidents are how most venomous animals first come to scientific notice, Brodie says. Early in his career, he discovered details of fire salamander venom by tickling a new specimen with a piece of grass. He was showing students how toxins ooze from its skin and “it sprayed me right in the eye,” he says. “I was immediately blinded.”
“I ran to the sink and ran water in my eye for about 20 minutes,” he says. “The toxin isn’t water soluble, so it didn’t help much. It was extraordinarily painful,” he notes in mild tones. Also, “the first time you observe something like that, you’re not sure it’s temporary blindness.” It was.
Venomous amphibians may be more common than people expect, Brodie says. Now that the researchers know about bone points for venom delivery, they want to investigate some salamanders with ribs that punch through the skin. And at least three more frogs grow suspicious spines around their heads. “It’s not Kermit anymore,” he says.
Editor’s Note: This story was updated on August 13, 2015, to clarify the habitat differences between the two venomous frogs.
With the blessings of all 14 families of lost astronauts, a new memorial to the Challenger and Columbia space shuttle disasters opened in June at the Kennedy Space Center in Florida. The permanent exhibit includes the first pieces of shuttle wreckage ever on public display, but fittingly focuses more on the lives lost.
“Forever Remembered” is housed inside the space center’s new $100 million exhibit about the space shuttle Atlantis. Below the nose of the intact shuttle, visitors enter a hall lit by tributes to each astronaut from the lost missions, those from Challenger on the left and Columbia on the right. Each display includes glimpses of the astronaut’s life. Items include plans for remodeling the home of Challenger pilot Michael Smith and a recovered page in Hebrew from the Columbia flight journal of Ilan Ramon, a payload specialist and the first Israeli astronaut. Past the hall, visitors enter a small gallery with a single piece of each shuttle: a body panel from Challenger (shown at left) and cockpit window frames from Columbia . There are no extended written descriptions or flashy videos. In short, it’s a place for pondering rather than learning. As a ninth-grader in school 50 miles away when Challenger exploded in 1986 and as an adult who waited for a telltale sonic boom that never came when Columbia was lost during re-entry in 2003, I found the effect powerful. The exhibit’s exit hallway reveals the tragedies from multiple perspectives on video displays. One video details the massive efforts to recover the wreckage and remains from the disasters, from the ocean for Challenger and from land for Columbia. Others focus on the emotional tolls and the critical shuttle launches that followed each completed investigation.
Michael Curie, Kennedy Space Center’s news chief, says family members have been both supportive and grateful for the exhibit. “They feel that it humanizes their family members in a way that never has been done before,” he says. Indeed, “Forever Remembered” is an effective reminder of the very real risks each astronaut willingly and bravely faced.
Boa constrictors don’t so much suffocate prey as break their hearts. It turns out that the snakes kill like demon blood pressure cuffs, squeezing down circulation to its final stop. The notion that constrictors slay by preventing breathing turns out to be wrong.
The snakes don’t need limbs, or even venom, to bring down an animal of their own size. “Imagine you’re killing and swallowing a 150-pound animal in one meal — with no hands or legs!” animal ecologist Scott Boback tells his students at Dickinson College in Carlisle, Pa., to convey what extraordinary hunters snakes are. Speed matters with prey flailing claws, hooves or other weaponry the snake lacks. Embracing prey into heart failure is faster than suffocating it and appeared in different forms multiple times in snake history. Ambushing birds, monkeys and a wide range of other animals from Mexico south to Argentina, the iconic Boa constrictor attacks in much the same way each time. The snake cinches a loop or two around the upper body of prey, pressing against its victim hard enough to starve organs of oxygenated blood.
“It’s not some unbelievable amount of pressure,” says Boback, whose arms get snaked now and then. “It stings a little — you can kind of feel the blood stop,” he says. Within six seconds of looping around an anesthetized lab rat, a boa constrictor squeezes enough to halve blood pressure in a rear-leg artery. Blood that should surge through the artery lies dammed behind snake coils in the rat’s upper body. And back pressure keeps the rat heart from pumping out new blood. Circulation falters and fails. Boas release their grip after about six minutes on average, Boback and his colleagues report in the July 15 Journal of Experimental Biology.
Then the boa swallows the catch whole. A rat about a quarter of the snake’s weight disappears down the gullet in a couple of minutes. Moveable bones in the head help the snake make the gulp, as does a dimple of stretchy cartilage that lets the chin open wide. But what people most often tell Boback — that snake jaws must separate at the back — is just another serpentine myth.
Icicles made from pure water give scientists brain freeze.
In nature, most icicles are made from water with a hint of salt. But lab-made icicles free from salt disobey a prominent theory of how icicles form, and it wasn’t clear why. Now, a study is helping to melt away the confusion.
Natural icicles tend to look like skinny cones with rippled surfaces — the result of a thin film of water that coats the ice, researchers think (SN: 11/24/13). As icicles grow, the film freezes. Any preexisting small bumps in the icicle get magnified into large ripples because the water layer is thinner above the bumps and can freeze more readily. But this theory fails to explain the salt-free variety, which have more irregular shapes reminiscent of drippy candles, says physicist Menno Demmenie of the University of Amsterdam. So Demmenie and colleagues grew icicles in the lab, adding a blue dye that was visible only when the water was liquid. Salted icicles not only had ripples, but they also were covered in a thin, blue film. Icicles made from pure water had no such film. Only small droplets of blue appeared on those icicles, the team reports in the February Physical Review Applied.
In icicles with salt, the temperature at which the water on the surface freezes is lowered, allowing a liquid layer to coat the entire icicle. Without the salt, icicles must build up drop by drop.