Controlling a single brain chemical may help expand window for learning language and music

This image shows (from left) Noah Roy, Ph.D., a postdoctoral research associate in Dr. Zakharenko's lab, and first author Jay Blundon, Ph.D., an associate scientist in Dr. Zakharenko's lab.

Learning language or music is usually a breeze for children, but as even young adults know, that capacity declines dramatically with age. St. Jude Children's Research Hospital scientists have evidence from mice that restricting a key chemical messenger in the brain helps extend efficient auditory learning much later in life.

Researchers showed that limiting the supply or the function of the neuromodulator adenosine in a brain structure called the auditory thalamus preserved the ability of adult mice to learn from passive exposure to sound much as young children learn from the soundscape of their world. The study appears June 30 in the journal Science.

"By disrupting adenosine signaling in the auditory thalamus, we have extended the window for auditory learning for the longest period yet reported, well into adulthood and far beyond the usual critical period in mice," said corresponding author Stanislav Zakharenko, M.D., Ph.D., a member of the St. Jude Department of Developmental Neurobiology. "These results offer a promising strategy to extend the same window in humans to acquire language or musical ability by restoring plasticity in critical regions of the brain, possibly by developing drugs that selectively block adenosine activity."

The auditory thalamus is the brain's relay station where sound is collected and sent to the auditory cortex for processing. The auditory thalamus and cortex rely on the neurotransmitter glutamate to communicate. Adenosine was known to reduce glutamate levels by inhibiting this neurotransmitter's release. This study also linked adenosine inhibition to reduced brain plasticity and the end of efficient auditory learning.

Researchers used a variety of methods to demonstrate that reducing adenosine or blocking the A1 adenosine receptor that is essential to the chemical messenger's function changed how adult mice responded to sound.

Much as young children pick up language simply by hearing it spoken, researchers showed that when adenosine was reduced or the A1 receptor blocked in the auditory thalamus, adult mice passively exposed to a tone responded to the same tone stronger when it was played weeks or months later. These adult mice also gained an ability to distinguish between very close tones (or tones with similar frequencies). Mice usually lack this "perfect pitch" ability.

Researchers also showed that the experimental mice retained the improved tone discrimination for weeks.

"Taken together, the results demonstrated that the window for effective auditory learning re-opened in the mice and that they retained the information," Zakharenko said.

Among the strategies researchers used to inhibit adenosine activity was the experimental compound FR194921, which selectively blocks the A1 receptor. If paired with sound exposure, the compound rejuvenated auditory learning in adult mice. "That suggests it might be possible to extend the window in humans by targeting the A1 receptor for drug development," Zakharenko said.

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Jupiter: Atmosphere and aurora in unprecedented detail

Image of Jupiter taken on May 18, 2017, one day before the Juno spacecraft's sixth close approach to Jupiter, taken with a filter centered at 8.8 microns that is sensitive to Jupiter's tropospheric temperatures and the thickness of a cloud near the condensation level of ammonia gas. The Great Red Spot appears distinctively at the lower center of the planet as a cold region with a thick cloud layer. It is surrounded by a warm and relatively clear periphery. To its northwest is a turbulent and chaotic region of gas with bands of alternative warm, dry and cold, moist gas. Many other features are also present. This image shows the detailed atmospheric structure of the Great Red Spot and its surroundings that the Juno mission will encounter on its seventh closest approach to Jupiter on July 11, 2017. The instrument used to take these images is Subaru Telescope's facility instrument COoled Mid-Infrared Camera / Spectrometer (COMICS).

Subaru Telescope images reveal weather in Jupiter's atmosphere in the mid-infrared. High-resolution thermal imaging of Jupiter by the COoled Mid-Infrared Camera and Spectrometer (COMICS) mounted on the Subaru Telescope on Maunakea is providing information that extends and enhances the information that the Juno mission is gathering in its unprecedented mission to probe that planet's interior and deep atmospheric structure together with details of the magnetosphere and its auroral interactions with the planet. "The Subaru observations of Jupiter so far this year have been timed to coordinate with the greatest benefit to Juno mission," said Glenn Orton, PI for the portion of the Keck Telescope exchange time with the Subaru Telescope and coordinator for Earth-based observations supporting the Juno project at JPL.

"During our May 2017 observations that provided real-time support for Juno's sixth perijove, we obtained images and spectra of the Great Red Spot and its surroundings. Our observations showed that the Great Red Spot, the largest known vortex in the solar system, had a cold and cloudy interior increasing toward its center, with a periphery that was warmer and clearer. This implied that winds were upwelling more vigorously toward its center and subsiding on the periphery. A region to its northwest was unusually turbulent and chaotic, with bands that were cold and cloudy, alternating with bands that were warm and clear bands. This region is where air heading east toward the Great Red Spot flows around it to the north, where it encounters a stream of air flowing over it from the east," adds Orton. "This information will allow us to determine the three-dimensional structure of winds that are otherwise only tracked in two dimensions using cloud features in reflected sunlight." "A wide variety of filters installed in COMICS is advantageous in sensing Jupiter's temperatures in its upper troposphere and in its stratosphere," noted co-investigator and Subaru Telescope staff astronomer Takuya Fujiyoshi.

Juno has now made five close-up passes of Jupiter's atmosphere, the first of which was on August 27, 2016 and the latest (the sixth) on May 19 of 2017. Each of these close passes has provided Juno's science team with unexpected surprises, and the Juno science return has benefited from a coordinated campaign of Earth-based support. This campaign includes observations from spacecraft near or orbiting the Earth, covering X-ray through visible wavelengths and ground-based observatories covering near-infrared through radio wavelengths.

Another set of supporting observations that were simultaneous with the Subaru observations were made by the Gemini North telescope's NIRI instrument, which imaged Jupiter in the near-infrared, measuring reflected sunlight from cloud and haze particle in Jupiter's upper troposphere and lower stratosphere -- levels generally higher in Jupiter's atmosphere than most of the Subaru measurements, providing complementary information. "Wide coverage of wavelength available from the telescopes on Maunakea is thus advantageous for the study," Fujiyoshi says.

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Under pressure: Extreme atmosphere stripping may limit exoplanets' habitability

This is an artist's impression of HD189733b, showing the planet's atmosphere being stripped by the radiation from its parent star.

New models of massive stellar eruptions hint at an extra layer of complexity when considering whether an exoplanet may be habitable or not. Models developed for our own Sun have now been applied to cool stars favoured by exoplanet hunters, in research presented by Dr Christina Kay, of the NASA Goddard Flight Center, on Monday 3rd July at the National Astronomy Meeting at the University of Hull.

Coronal mass ejections (CMEs) are huge explosions of plasma and magnetic field that routinely erupt from the Sun and other stars. They are a fundamental factor in so called "space weather," and are already known to potentially disrupt satellites and other electronic equipment on Earth. However, scientists have shown that the effects of space weather may also have a significant impact on the potential habitability of planets around cool, low mass stars -- a popular target in the search for Earth-like exoplanets.

Traditionally an exoplanet is considered "habitable" if its orbit corresponds to a temperature where liquid water can exist. Low mass stars are cooler, and therefore should have habitable zones much closer in to the star than in our own solar system, but their CMEs should be much stronger due to their enhanced magnetic fields.

When a CME impacts a planet, it compresses the planet's magnetosphere, a protective magnetic bubble shielding the planet. Extreme CMEs can exert enough pressure to shrink a magnetosphere so much that it exposes a planet's atmosphere, which can then be swept away from the planet. This could in turn leave the planetary surface and any potential developing lifeforms exposed to harmful X-rays from the nearby host star.

The team built on recent work done at Boston University, taking information about CMEs in our own solar system and applying it to a cool star system.

"We figured that the CMEs would be more powerful and more frequent than solar CMEs, but what was unexpected was where the CMEs ended up" said Christina Kay, who led the research during her PhD work.

The team modelled the trajectory of theoretical CMEs from the cool star V374 Pegasi and found that the strong magnetic fields of the star push most CMEs down to the Astrophysical Current Sheet (ACS), the surface corresponding to the minimum magnetic field strength at each distance, where they remain trapped.

"While these cool stars may be the most abundant, and seem to offer the best prospects for finding life elsewhere, we find that they can be a lot more dangerous to live around due to their CMEs" said Marc Kornbleuth, a graduate student involved in the project.

The results suggest that an exoplanet would need a magnetic field ten to several thousand times that of Earth's to shield their atmosphere from the cool star's CMEs. As many as five impacts a day could occur for planets near the ACS, but the rate decreases to one every other day for planets with an inclined orbit.

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'Perfect storm' led to 2016 Great Barrier Reef bleaching

Aerial view of the Great Barrier Reef.

Researchers from James Cook University and the Université catholique de Louvain, Louvain-la-Neuve, Belgium say unprecedented oceanographic conditions in 2016 produced the perfect storm of factors that lead to a mass coral bleaching.

JCU's Professor Eric Wolanski said even in very warm years with a summer el Nino event, such as 1998, there was no massive coral bleaching in the Torres Strait and only small to moderate bleaching in the northern Great Barrier Reef.

"So, the extensive coral bleaching in these areas during the summer of 2016 was an unwelcome surprise," he said.

A 2016 aerial survey of the northern Great Barrier Reef lead by Professor Terry Hughes from JCU's Center of Excellence for Coral Reef Studies showed that 90 per cent of reefs in some of these areas were severely bleached.

Professor Wolanski said satellite data showed the 2016 El Nino heating started in the Gulf of Carpentaria, with patches of water reaching an exceptionally high 34oC.

The water then flowed east onto the Torres Strait reefs and south to the Great Barrier Reef. The 'residence time' of the very warm water in the Torres Strait and the Northern Great Barrier Reef was exceptionally long, which increased the thermal stress on the coral.

All of these factors enabled local solar heating to proceed unrestricted.

"Examining surface currents suggests that the North Queensland Coastal Current in the Coral Sea, which would normally flush and cool the Northern Great Barrier Reef, actually did the opposite. It reversed course and brought very warm water to the Northern Great Barrier Reef."

Professor Wolanski said these processes together made it the perfect thermal storm.

He said the study employed oceanography models used extensively to study water flow in the region, which were then calibrated with real oceanographic data.

Professor Wolanski said the study was subjective to the extent that there was a lack of oceanographic field data in the Great Barrier Reef itself for the 2016 el Nino event. By contrast, the amount of oceanographic field data in the Torres Strait and the northern Coral Sea was very good.

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Social status of listener alters our voice

Men and women might speak with higher-pitched voices towards high status people because a low-pitched voice sounds dominant, particularly in men, while a high-pitched voice sounds relatively submissive.

People tend to change the pitch of their voice depending on who they are talking to, and how dominant they feel, a study by the University of Stirling has found.

The psychology research, published in PLOS ONE, put participants through a simulated job interview task and discovered that individuals' vocal characteristics -- particularly pitch -- are altered in response to people of different social status.

Regardless of self-perceived social status, people tend to talk to high status individuals using a higher pitch.

Dr Viktoria Mileva, a Postdoctoral Researcher at the University of Stirling, said: "A deep, masculine voice sounds dominant, especially in men, while the opposite is true of a higher pitched voice. So, if someone perceives their interviewer to be more dominant than them, they raise their pitch. This may be a signal of submissiveness, to show the listener that you are not a threat, and to avoid possible confrontations.

"These changes in our speech may be conscious or unconscious but voice characteristics appear to be an important way to communicate social status. We found both men and women alter their pitch in response to people they think are dominant and prestigious."

The researchers also found that participants who think they are dominant -- who use methods like manipulation, coercion, and intimidation to acquire social status -- are less likely to vary their pitch and will speak in a lower tone when talking to someone of a high social status.

Individuals who rate themselves as high in prestige -- they believe people look up to them and value their opinions, thereby granting them social status -- do not change how loud they are speaking, no matter who they are speaking to. This may signal that they are more calm and in control of a situation.

The participants responded to introductory, personal, and interpersonal interview questions. They lowered the pitch of their voice most in response to the more complex, interpersonal questions, for example when explaining a conflict situation to an employer.

Dr Mileva added: "Signals and perceptions of human social status have an effect on virtually every human interaction, ranging from morphological characteristics -- such as face shape -- to body posture, specific language use, facial expressions and voices.

"Understanding what these signals are, and what their effects are, will help us comprehend an essential part of human behaviour."

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Study reveals mysterious equality with which grains pack it in

A huge range of materials are classified as granular – including sand, gravel, snow, nuts, coal, rice, barley, coffee and cereals. Globally, they are the second-most processed type of material in industry, after water.

At the moment they come together, the individual grains in materials like sand and snow appear to have exactly the same probability of combining into any one of their many billions of possible arrangements, researchers have shown.

The finding, by an international team of academics at the University of Cambridge, UK, and Brandeis University in the US, appears to confirm a decades-old mathematical theory which has never been proven, but provides the basis for better understanding granular materials -- one of the most industrially significant classes of material on the planet.

A granular material is anything that comprises solid particles that can be seen individually with the naked eye. Examples include sand, gravel, snow, coal, coffee, and rice.

If correct, the theory demonstrated in the new study points to a fact of remarkable -- and rather mysterious -- mathematical symmetry. It means, for example, that every single possible arrangement of the grains of sand within a sand dune is exactly as probable as any another.

The study was led by Stefano Martiniani, who is based at New York University but undertook the research while completing his PhD at St John's College, University of Cambridge.

"Granular materials are so widely-used that understanding their physics is very important," Martiniani said. "This theory gives us a very simple and elegant way to describe their behaviour. Clearly, something very special is happening in their physics at the moment when grains pack together in this way."

The conjecture that Martiniani tested was first proposed in 1989 by the Cambridge physicist Sir Sam F. Edwards, in an effort to better understand the physical properties of granular materials.

Globally, these are the second-most processed type of material in industry (after water) and staples of sectors such as energy, food and pharmaceuticals. In the natural world, vast granular assemblies, such as sand dunes, interact directly with wind, water and vegetation. Yet the physical laws that determine how they behave in different conditions are still poorly understood. Sand, for example, behaves like a solid when jammed together, but flows like a liquid when loose.

Understanding more about the mechanics of granular materials is of huge practical importance. When they jam during industrial processing, for example, it can cause significant disruption and damage. Equally, the potential for granular materials to "unjam" can be disastrous, such as when soil or snow suddenly loosens, causing a landslide or avalanche.

At the heart of Edwards' proposal was a simple hypothesis: If one does not explicitly add a bias when preparing a jammed packing of granular materials -- for example by pouring sand into a container -- then any possible arrangement of the grains within a certain volume will occur with the same probability.

This is the analogue of the assumption that is at the heart of equilibrium statistical mechanics -- that all states with the same energy occur with equal probability. As a result the Edwards hypothesis offered a way for researchers to develop a statistical mechanics framework for granular materials, which has been an area of intense activity in the last couple of decades.

But the hypothesis was impossible to test -- not least because above a handful of grains, the number of possible arrangements becomes unfathomably huge. Edwards himself died in 2015, with his theory still the subject of heated scientific debate.

Now, Martiniani and colleagues have been able to put his conjecture to a direct test, and to their surprise they found that it broadly holds true. Provided that the grains are at the point where they have just jammed together (or are just about to separate), all possible configurations are indeed equally likely.

Helpfully, this critical point -- known as the jamming transition -- is also the point of practical significance for many of the granular materials used in industry. Although Martiniani modelled a system comprising soft spheres, a bit like sponge tennis balls, many granular materials are hard grains that cannot be compressed further once in a packed state.

"Apart from being a very beautiful theory, this study gives us the confidence that Edwards' framework was correct," Martiniani said. "That means that we can use it as a lens through which to look at a whole range of related problems."

Aside from informing existing processes that involve granular materials, there is a wider significance to better understanding their mechanics. In physics, a "system" is anything that involves discrete particles operating as part of a wider network. Although bigger in scale, the way in which icebergs function as part of an ice floe, or the way that individual vehicles move within a flow of traffic (and indeed sometimes jam), can be studied using a similar theoretical basis.

Martiniani's study was undertaken during his PhD under the supervision of Professor Daan Frenkel. It built on earlier research in which he developed new methods for calculating the probability of granular systems packing into different configurations, despite the vast numbers involved. In work published last year, for example, he and colleagues used computer modelling to work out how many ways a system containing 128 tennis balls could potentially be arranged. The answer turned out to be ten unquadragintilliard -- a number so huge that it vastly exceeds the total number of particles in the universe.

In the new study, the researchers employed a sampling technique which attempts to compute the probability of different arrangements of grains without actually looking at the frequency with which these arrangements occur. Rather than taking an average from random samples, the method involves calculating the limits of the possibility of specific arrangements, and then calculates the overall probability from this.

The team applied this to a computer model of 64 soft spheres -- an imaginary system which could therefore be "over-compressed" after reaching the jamming transition point. In an over-compressed state, the different arrangements were found to have different probabilities of occurrence. But as the system decompressed to the point of the jamming transition, at which the grains were effectively just touching, the researchers found that all probabilities became equal -- exactly as Edwards predicted.

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Surprisingly exact timing of voluntary movements

Dan-Anders Jirenhed and Anders Rasmussen.

Almost everything we do -- walking, talking, or drinking coffee -- is completely dependent on accurate timing when activating many muscles at once. The prevailing theory has been that the exact timing of this type of movement is not voluntarily controlled, and the timing has therefore been assumed to be fully automated when learning movements. However, researchers at Lund University in Sweden now argue that this may be wrong. A new study shows that people are fully capable of controlling their blinking with a time precision that was previously believed not to be possible.

It has long been known that both animals and humans, through a type of learning known as eyeblink conditioning, can learn to blink in response to a tone with a precision of some tens of milliseconds. Previous studies have shown that eyeblink conditioning is dependent on the cerebellum and, so far, it has been assumed that the precise timing is completely automatic.

When researchers Anders Rasmussen and Dan-Anders Jirenhed performed laboratory studies as part of their teaching at the medical programme at Lund University, they discovered that the theory was incorrect in practice.

Rasmussen and Jirenhed tested 21 medical students at Lund University and could see that the students were able to control the exact timing of their blinking with unexpected accuracy. The researchers' results, now published in Scientific Reports, question whether previous studies on human eyeblink conditioning have, in fact, studied purely automated learning or if the test subjects also voluntarily controlled their their blinking.

"Our results are an important step in understanding how the human brain can control the timing of our movements -- and to what extent we can influence them at will," says Anders Rasmussen.

The fact that the movements can be controlled at will also shows that the cerebral cortex, perhaps through cooperation with the cerebellum, can play an important role in terms of timing.

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Birds become immune to influenza

Pair of mallards.

An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.

Water birds, in particular mallards, are often carriers of low-pathogenic influenza A virus. Researchers previously believed that birds infected by one variant of the virus could not benefit from it by building up immunity against other virus subtypes. However, the recent study concludes that mallards infected with a low-pathogenic virus build up significant immunity and resistance to other variants of the same virus.

"It was previously thought that the birds were not particularly good at protecting themselves against subsequent infections, but in fact they manage quite well," says Neus Latorre-Margalef, a biologist at Lund University.

The study conducted by Latorre-Margalef, together with colleagues from the University of Georgia in the US, shows that, after an infection, mallards become partially immune and resistant to influenza infections to which they are later exposed. How high their resistance is depends partly on which viruses are involved, and on how genetically similar they are.

"For future infections, the birds' previous infections are important. Birds which have had influenza could be partially protected against virulent variants such as H5N1 or H5N8," says Neus Latorre-Margalef.

The H5N1 and H5N8 strains are highly pathogenic and those most often associated with avian flu. Just over ten years ago, H5N1 spread around the world from chicken flocks in Southeast Asia. Both domestic poultry flocks and wild bird populations were gravely affected. Humans also became ill, in some cases fatally.

It is unclear why there are more subtypes of influenza among birds than among humans and other mammals. One explanation could be what Neus Latorre-Margalef and her colleagues show in their study: that various viruses compete with one another as birds build up immunity and the duration of infection becomes shorter. The virus then gets a chance to mutate and change.

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The sharpest laser in the world

This is one of the two silicon resonators.

No one had ever come so close to the ideal laser before: theoretically, laser light has only one single color (also frequency or wavelength). In reality, however, there is always a certain linewidth. With a linewidth of only 10 mHz, the laser that the researchers from the Physikalisch-Technische Bundesanstalt (PTB) have now developed together with US researchers from JILA, a joint institute of the National Institute of Standards and Technology and the University of Colorado Boulder, has established a new world record. This precision is useful for various applications such as optical atomic clocks, precision spectroscopy, radioastronomy and for testing the theory of relativity. The results have been published in the current issue of Physical Review Letters.

Lasers were once deemed a solution without problems -- but that is now history. More than 50 years have passed since the first technical realization of the laser, and we cannot imagine how we could live without them today. Laser light is used in numerous applications in industry, medicine and information technologies. Lasers have brought about a real revolution in many fields of research and in metrology -- or have even made some new fields possible in the first place.

One of a laser's outstanding properties is the excellent coherence of the emitted light. For researchers, this is a measure for the light wave's regular frequency and linewidth. Ideally, laser light has only one fixed wavelength (or frequency). In practice, the spectrum of most types of lasers can, however, reach from a few kHz to a few MHz in width, which is not good enough for numerous experiments requiring high precision.

Research has therefore focused on developing ever better lasers with greater frequency stability and a narrower linewidth. Within the scope of a nearly 10-year-long joint project with the US colleagues from JILA in Boulder, Colorado, a laser has now been developed at PTB whose linewidth is only 10 mHz (0.01 Hz), hereby establishing a new world record. "The smaller the linewidth of the laser, the more accurate the measurement of the atom's frequency in an optical clock. This new laser will enable us to decisively improve the quality of our clocks," PTB physicist Thomas Legero explains.

In addition to the new laser's extremely small linewidth, Legero and his colleagues found out by means of measurements that the emitted laser light's frequency was more precise than what had ever been achieved before. Although the light wave oscillates approx. 200 trillion times per second, it only gets out of sync after 11 seconds. By then, the perfect wave train emitted has already attained a length of approx. 3.3 million kilometers. This length corresponds to nearly ten times the distance between Earth and the moon.

Since there was no other comparably precise laser in the world, the scientists working on this collaboration had to set up two such laser systems straight off. Only by comparing these two lasers was it possible to prove the outstanding properties of the emitted light.

The core piece of each of the lasers is a 21-cm long Fabry-Pérot silicon resonator. The resonator consists of two highly reflecting mirrors which are located opposite each other and are kept at a fixed distance by means of a double cone. Similar to an organ pipe, the resonator length determines the frequency of the wave which begins to oscillate, i.e., the light wave inside the resonator. Special stabilization electronics ensure that the light frequency of the laser constantly follows the natural frequency of the resonator. The laser's frequency stability -- and thus its linewidth -- then depends only on the length stability of the Fabry-Pérot resonator.

The scientists at PTB had to isolate the resonator nearly perfectly from all environmental influences which might change its length. Among these influences are temperature and pressure variations, but also external mechanical perturbations due to seismic waves or sound. They have attained such perfection in doing so that the only influence left was the thermal motion of the atoms in the resonator. This "thermal noise" corresponds to the Brownian motion in all materials at a finite temperature, and it represents a fundamental limit to the length stability of a solid. Its extent depends on the materials used to build the resonator as well as on the resonator's temperature.

For this reason, the scientists of this collaboration manufactured the resonator from single-crystal silicon which was cooled down to a temperature of -150 °C. The thermal noise of the silicon body is so low that the length fluctuations observed only originate from the thermal noise of the dielectric SiO2/Ta2O5 mirror layers. Although the mirror layers are only a few micrometers thick, they dominate the resonator's length stability. In total, the resonator length, however, only fluctuates in the range of 10 attometers. This length corresponds to no more than a ten-millionth of the diameter of a hydrogen atom. The resulting frequency variations of the laser therefore amount to less than 4 × 10-17 of the laser frequency.

The new lasers are now being used both at PTB and at JILA in Boulder to further improve the quality of optical atomic clocks and to carry out new precision measurements on ultracold atoms. At PTB, the ultrastable light from these lasers is already being distributed via optical waveguides and is then used by the optical clocks in Braunschweig.

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Ancient Swiss reptile shows its bizarre scale armor for the first time

Reconstruction of Eusaurosphargis dalsassoi.

Grisons, 241 million years ago -- Instead of amidst high mountains, a small reptile suns itself on an island beach in a warm shallow sea, where many fish and marine reptiles frolic. This is the story told by an excellently preserved new discovery of the reptile Eusaurosphargis dalsassoi studied by paleontologists from the University of Zurich.

About 20 centimeters in length, the Swiss reptile was small and juvenile, but its skin was already strongly armored with variously formed smooth, jagged or even thorny osteoderms. Its skeleton indicates a life on land, even though the animal was found together with fish and marine reptiles in the 241 million year old calcareous deposits of the Prosanto Formation near Ducanfurgga at an altitude of 2,740 meters south of Davos in the canton Grisons, Switzerland. The Swiss-British team of researchers led by Torsten Scheyer, paleontologist at the University of Zurich, and James Neenan from the Oxford University Museum of Natural History therefore assumes that it was washed off a nearby island into the sea basin and became embedded in the finely layered marine sediments after death.

Skeleton and appearance reconstructed

14 years ago, the species Eusaurosphargis dalsassoi was described using a partially preserved, completely disarticulated sample from the vicinity of the Swiss-Italian UNESCO World Heritage Site Monte San Giorgio. The new find from the Grisons Mountains, on the other hand, is very well-preserved, allowing researchers to reconstruct the skeleton and outward appearance of the animal for the first time.

In the process, they discovered something astonishing: Externally, Eusaurosphargis dalsassoi looks very similar to girdled lizards (Cordylidae), a group of small, scaled reptiles (Lepidosauria) that usually live in the dry regions of southern Africa. Some of the more strongly armored girdled lizard species could have served as the basis of mythical dragon legends due to their appearance. "This is a case of convergent development as the extinct species is not closely related to today's African lizards" , Scheyer explains.

Related to Helveticosaurus

An exact examination of the phylogenetic relationships rather confirms that its closest relatives are marine reptiles such as ichthyosaurs (Ichthyosauria or "fish lizards"), sauropterygians (Sauropterygia "lizard flippers") or even Helveticosaurus, a marine reptile that is unique to Switzerland, all of which have been found at Monte San Giorgio. The skeleton of Eusaurosphargis, however, shows neither a streamlined body structure, nor arms and legs that have transformed into flippers, as well as no tail fin, which would indicate a life at sea.

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