Enlarge / Artist's reconstruction of the shark as it once lived. (credit: Klug et. al. )

Sharks are largely cartilaginous, a body structure that often doesn’t survive fossilization. But in a paper published in the Swiss Journal of Paleontology, scientists describe an entirely new species of primitive shark from the Late Devonian period, a time when they were just beginning to proliferate in ancient oceans.

The team found several exceptionally well-preserved fossils that include soft tissues such as scales, musculature, digestive tract, liver, and blood vessel imprints. Also preserved: the species’ most distinct feature, widely separated nasal organs, somewhat akin to those on today’s hammerhead sharks. The find suggests that sharks’ finely tuned sense of smell, the subject of urban legends, was already being selected for just as these predators were becoming established.

A key time and a rare find

Christian Klug is the lead author and curator of the Paleontological Institute and Museum at Zurich University. He explained the significance of the Devonian period in the oceans’ history, when life was flourishing and an evolutionary arms race was in full swing. “With increasing competition among predators inhabiting the water column, the entire organism was selected for more efficiency,” he explained. “This affected swimming abilities, feeding apparatus, but also the sensory systems, which are essential to detect prey, to orient themselves in space, and to escape from even larger predators such as the huge placoderm Dunkleosteus and the equally large shark Ctenacanthus .”

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Most creatures sleep, but until now, REM (rapid eye movement) sleep , the phase of sleep in which dreams occur, was thought to be exclusive to vertebrates. Octopuses appear to be the first invertebrates to show they are also capable of this

When it comes to neural function, studies have found these cephalopods are more like us than we think (pun somewhat intended). Having no spine hasn’t stopped them from evolving a complex nervous system. A 2022 study found that parts of their brains, the frontal and vertical lobes, work much like the hippocampus and limbic lobe in humans and other vertebrates. The hippocampus is critical to learning and memory, while the limbic lobe controls complex emotional reactions, such as the fight-or-flight response that is triggered by stress or fear.

Now it seems that octopuses have even more in common with us. In studying their sleep behavior, a team of researchers at the Okinawa Institute of Science and Technology observed both periods of quiet sleep, or NREM sleep (also known as slow wave sleep), and bursts of neural activity, during which the animals’ eyes and tentacles twitched while their skin changed color. Neural activities like these, which are similar to the waking state, only happen during REM sleep. Because they can transition between NREM and REM sleep, octopuses are the only known invertebrates that have two phases of sleep.

Enlarge / All steroids past and present share the complex ringed structure but differ in terms of the atoms attached to those rings. (credit: KATERYNA KON/SCIENCE PHOTO LIBRARY )

All of the organisms we can see around us—the plants, animals, and fungi—are eukaryotes composed of complex cells. Their cells have many internal structures enclosed in membranes, which keep things like energy production separated from genetic material, and so on. Even the single-celled organisms on this branch of the tree of life often have membrane-covered structures that they move and rearrange for feeding.

Some of that membrane flexibility comes courtesy of steroids. In multicellular eukaryotes, steroids perform various functions; among other things, they’re used as signaling molecules, like estrogen and testosterone. But all eukaryotes insert various steroids into their membranes, increasing their fluidity and altering their curvature. So the evolution of an elaborate steroid metabolism may have been critical to enabling complex life.

Now, researchers have traced the origin of eukaryotic steroids almost a billion years further back in time. The results suggest that many branches of the eukaryotic family tree once made early versions of steroids. But our branch evolved the ability to produce more elaborate ones—which may have helped us outcompete our relatives.

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How, exactly, living things emerged on Earth remains a mystery. Now a new experiment has revealed that blasts of solar particles could have kickstarted the process by creating some of the basic components of life.

Time in the sun

Before so much as the first microbe existed, there had to be amino acids thought to have formed in one of the primordial oozes of early Earth. It was previously thought that lightning might have supercharged the formation of amino acids. However, Kensei Kobayashi of Yokohama National University in Japan, along with astrophysicist Vladimir Airapetian of NASA’s Goddard Space Flight Center and a team of researchers from both institutions, have found another possibility: The young Sun’s superflares probably helped give rise to the stuff of life.

“[Galactic cosmic rays] and [solar energetic particle] events from the young Sun represent the most effective energy sources for the prebiotic formation of biologically important organic compounds,” the researchers said in a study recently published in Life .

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Sleep is a semiconscious state, but there are neurons firing in the brain even when all seems quiet. Now brain activity during the deepest sleep phase could make it possible for people to communicate with the waking world during lucid dreaming.

If someone is lucid dreaming, they are aware they are dreaming and able to manipulate what happens in the dream. Sleep expert Michael Raduga of Phase Research Center has developed a “language” that’s intended to allow people to communicate while in that state. Called Remmyo, the first language of its kind, relies on specific facial muscle movements that can occur during rapid eye movement (REM) sleep. Remmyo can be learned during waking hours like any other language. Anyone capable of lucid dreaming could potentially communicate in Remmyo while asleep.

“You can transfer all important information from lucid dreams using no more than three letters in a word,” Raduga, who founded Phase Research Center in 2007 to study sleep, told Ars. “This level of optimization took a lot of time and intellectual resources.”

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Broad-spectrum antibiotics are akin to nuclear bombs, obliterating every prokaryote they meet. They're effective at eliminating pathogens, sure, but they're not so great for maintaining a healthy microbiome. Ideally, we need precision antimicrobials that can target only the harmful bacteria while ignoring the other species we need in our bodies, leaving them to thrive. Enter SNIPR BIOME , a Danish company founded to do just that. Its first drug—SNIPR001—is currently in clinical trials .

The drug is designed for people with cancers involving blood cells. The chemotherapy these patients need can cause immunosuppression along with increased intestinal permeability, so they can't fight off any infections they may get from bacteria that escape from their guts into their bloodstream. The mortality rate from such infections in these patients is around 15–20 percent. Many of the infections are caused by E. coli , and much of this E. coli is already resistant to fluoroquinolones, the antibiotics commonly used to treat these types of infections.

The team at SNIPR BIOME engineers bacteriophages, viruses that target bacteria, to make them hyper-selective. They started by screening 162 phages to find those that would infect a broad range of E. coli strains taken from people with bloodstream or urinary tract infections, as well as from the guts of healthy people. They settled on a set of eight different phages. They then engineered these phages to carry the genes that encode the CRISPR DNA-editing system, along with the RNAs needed to target editing to a number of essential genes in the E. coli genome. This approach has been shown to prevent the evolution of resistance.

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We have various ways of seeing what the brain is up to, from low-resolution electrodes that track waves of activity that ripple across the brain, to implanted electrodes that can follow the activity of individual cells. Combined with a detailed knowledge of which regions of the brain are involved in specific processes, we've been able to do remarkable things, such as using functional MRI (fMRI) to determine what letter a person was looking at or an implant to control a robotic arm

But today, researchers announced a new bit of mind reading that's impressive in its scope. By combining fMRI brain imaging with a system that's somewhat like the predictive text of cell phones, they've worked out the gist of the sentences a person is hearing in near real time. While the system doesn't get the exact words right and makes a fair number of mistakes, it's also flexible enough that it can reconstruct an imaginary monologue that goes on entirely within someone's head.

Making functional MRI functional

Functional MRI is a way of seeing what parts of the brain have been active. By tuning the sensitivity of the imaging to pick up differences in the flow of blood, it's possible to identify areas within the brain that are replenishing their energy after having processed some information. It has been extremely useful for understanding how the brain operates, but it also has some significant limitations.

Enlarge (credit: A. Martin UW Photography )

Nine brains, blue blood, instant camouflage: It’s no surprise that octopuses capture our interest and our imaginations. Science-fiction creators , in particular, have been inspired by these tentacled creatures.

An octopus's remarkable intelligence makes it a unique subject for marine biologists and neuroscientists as well. Research has revealed the brain power of the octopus allows it to unscrew a jar or navigate a maze. But, like many children, the octopus also develops an impish tendency to push the boundaries of behavior. Several aquariums have found octopuses memorizing guard schedules to sneak into nearby tanks to steal fish; meanwhile, marine biologists have discovered that wild octopuses will punch fish … for no apparent reason.

According to Dr. Jennifer Maher , a professor at the University of Lethbridge in Canada, there are a “number of [different] types of learning [for octopuses]: cognitive tasks like tool use, memory of complex operations for future use, and observational learning.”

Enlarge (credit: Beth Zaiken)

An international team of scientists has published the results of their research into 23 woolly mammoth genomes in Current Biology . As of today, we have even more tantalizing insights into their evolution, including indications that, while the woolly mammoth was already predisposed to life in a cold environment, it continued to make further adaptations throughout its existence.

Years of research, as well as multiple woolly mammoth specimens, enabled the team to build a better picture of how this species adapted to the cold tundra it called home. Perhaps most significantly, they included a genome they had previously sequenced from a woolly mammoth that lived 700,000 years ago, around the time its species initially branched off from other types of mammoth. Ultimately, the team compared that to a remarkable 51 genomes—16 of which are new woolly mammoth genomes: the aforementioned genome from Chukochya, 22 woolly mammoth genomes from the Late Quaternary, one genome of an American mastodon (a relative of mammoths), and 28 genomes from extant Asian and African elephants.

From that dataset, they were able to find more than 3,000 genes specific to the woolly mammoth. And from there, they focused on genes where all the woolly mammoths carried sequences that altered the protein compared to the version found in their relatives. In other words, genes where changes appear to have been naturally selected.