Exquisitely preserved embryo found inside fossilized dinosaur egg

A 72 to 66-million-year-old embryo found inside a fossilised dinosaur egg sheds new light on the link between the behaviour of modern birds and dinosaurs, according to a new study.

The embryo, dubbed 'Baby Yingliang', was discovered in the Late Cretaceous rocks of Ganzhou, southern China and belongs to a toothless theropod dinosaur, or oviraptorosaur. Among the most complete dinosaur embryos ever found, the fossil suggests that these dinosaurs developed bird-like postures close to hatching.

Scientists found the posture of 'Baby Yingliang' unique among known dinosaur embryos -- its head lies below the body, with the feet on either side and the back curled along the blunt end of the egg. Previously unrecognised in dinosaurs, this posture is similar to that of modern bird embryos.

In modern birds, such postures are related to 'tucking' -- a behaviour controlled by the central nervous system and critical for hatching success. After studying egg and embryo, researchers believe that such pre-hatching behaviour, previously considered unique to birds, may have originated among non-avian theropods.

Led by scientists from the University of Birmingham and China University of Geosciences (Beijing), the research team from institutions in China, UK and Canada today published its findings in iScience.

The embryo is articulated in its life position without much disruption from fossilisation. Estimated to be 27 cm long from head to tail, the creature lies inside a 17-cm-long elongatoolithid egg. The specimen is housed in Yingliang Stone Nature History Museum.

Fion Waisum Ma, joint first author and PhD researcher at the University of Birmingham, said: "Dinosaur embryos are some of the rarest fossils and most of them are incomplete with the bones dislocated. We are very excited about the discovery of 'Baby Yingliang' -- it is preserved in a great condition and helps us answer a lot of questions about dinosaur growth and reproduction with it.

"It is interesting to see this dinosaur embryo and a chicken embryo pose in a similar way inside the egg, which possibly indicates similar prehatching behaviours."

'Baby Yingliang' was identified as an oviraptorosaur based on its deep, toothless skull. Oviraptorosaurs are a group of feathered theropod dinosaurs, closely related to modern-day birds, known from the Cretaceous of Asia and North America. Their variable beak shapes and body sizes are likely to have allowed them to adopt a wide range of diets, including herbivory, omnivory and carnivory.

Birds are known to develop a series of tucking postures, in which they bend their body and bring their head under their wing, soon before hatching. Embryos that fail to attain such postures have a higher chance of death due to unsuccessful hatching.

By comparing 'Baby Yingliang' with the embryos of other theropods, long-necked sauropod dinosaurs and birds, the team proposed that tucking behaviour, which was considered unique to birds, first evolved in theropod dinosaurs many tens or hundreds of millions of years ago. Additional discoveries of embryo fossils would be invaluable to further test this hypothesis.

Professor Lida Xing from China University of Geosciences (Beijing), joint first author of the study, said: "This dinosaur embryo was acquired by the director of Yingliang Group, Mr Liang Liu, as suspected egg fossils around the 2000. During the construction of Yingliang Stone Nature History Museum in 2010s, museum staff sorted through the storage and discovered the specimens.

"These specimens were identified as dinosaur egg fossils. Fossil preparation was conducted and eventually unveiled the embryo hidden inside the egg. This is how 'Baby Yingliang' was brought to light."

Read more at Science Daily

The Hitchhiker’s guide to the soil

The interaction of fungi and bacteria in the transport of viruses in the soil ecosystem has been examined by a UFZ research team in a study recently published in the journal of the International Society for Microbial Ecology (ISME Journal). The scientists showed a novel mechanism of viral transport by bacterial shuttles traveling along fungal hyphae. Bacteria thereby benefit from taking along viruses on the conquest of new habitats.

There are up to one billion viruses in just one gram of soil. However, little is known about their influence on the nutrient and carbon cycle in the soil ecosystem. Soils can sometimes be inhospitable places. Dry zones and air-filled soil pores are almost impossible obstacles for bacteria and viruses. In order for them to move around -- for example, to get to a place with better conditions -- they need water. But the situation is not completely hopeless. Because there is an excellently developed infrastructure in the soil: the fungal network. Fungi are always in search of water and nutrients. To do this, they form hyphae, long, thin threads that run through the soil as a widely branched network. Fungi are thus able to bridge dry and nutrient-poor zones.

In an earlier study, UFZ researchers showed that soil bacteria use the mucus-covered fungal hyphae in order to move around on them and thus reach new food sources. In their current study, the research team led by environmental microbiologist Dr. Lukas Y. Wick has now been able to identify another beneficiary of the underground fungal network. "Phages, i.e. viruses that have bacteria as their sole target, also travel this fungal highway," says Wick. "Not independently but rather by hitching a ride with bacteria. Physical forces cause the viruses to adhere to the surface of bacteria -- much like mussels adhere to the hull of a ship." In this way, viruses hitch a ride through the soil -- until they arrive at a place that is better suited for them. But what exactly is a good place for soil-dwelling viruses?

"Wherever the host bacteria of the viruses are found," says Wick. "Not every phage can infect every bacterium," says Wick. "Because of a kind of lock-and-key principle, phages can smuggle their genetic material only into their respective host bacteria." If this succeeds, the bacterium is reprogrammed to produce new phages. The bacterial cell then bursts, thereby releasing the phages of the next generation. These can then once again infect new host bacteria. "The phages are highly efficient at this. This obviously also gives the shuttle bacteria a real advantage," says Wick. "We were able to show that soil bacteria with phages attached to them were able to spread far better in their new location than bacteria without this viral baggage."

It is well known from macro-ecology that migratory species can cause problems for the established residents of a habitat. Also that invasive species can bring pathogens that increasingly contribute to the displacement of native species. The UFZ research group therefore interpreted their data using MAFIA (MAecological Framework of Invasive Aliens), a well-known model of invasion ecology. "With our fungus-bacteria-phage system, we were able to detect the same invasion patterns on a micro-scale as we did in the macro-ecological system," says Wick. "And because our microbial laboratory model can be quickly and easily sampled and modified, it could be used as a model system to answer various questions and hypotheses in invasion ecology -- such as the transport of pests or pathogens."

For their studies, the research team recreated a micro-attack of bacteria and phages in the laboratory. For this purpose, two zones with culture medium were used. These were connected to each other only via fungal hyphae. "In Zone A, we used typical soil bacteria as shuttles as well as phages that cannot harm this bacterial species," explains Xin You, first author of the study and PhD student at the UFZ Department of Environmental Microbiology. "Zone B was colonised with a phage-specific host bacterium." In different experimental approaches, the research team had the shuttle bacteria travel along the fungal hyphae highway with and without viral baggage. "The result was clear: the bacteria-phage duo had a clear advantage in the invasion of Zone B," says You. "The shuttle bacteria benefited from the power of the phages, which effectively disabled their host bacteria and thus also eliminated food competition for the invading bacteria."

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Where does the special scent of thyme and oregano come from?

Thyme and oregano are not only popular herbs for cooking, but also valuable medicinal plants. Their essential oils contain thymol and carvacrol which impart the typical flavors and are medically important. A team from Martin Luther University Halle-Wittenberg (MLU) and Purdue University in the USA has now fully identified how the plants produce these two substances. The results could simplify the breeding process and improve the pharmaceutical value of thyme and oregano. The study appears in the journal Proceedings of the National Academy of Sciences.

Thymol, which is mainly extracted from thyme, has secretolytic, antibacterial and antispasmodic properties. The plant is therefore often used in tea for colds, cough syrups and as an herbal remedy for bronchitis. In contrast, oregano contains particularly high levels of carvacrol, which has similar properties. Its smell is often associated with pizza sauce and other Mediterranean dishes. Both substances are chemically closely related and are produced by thyme and oregano in multi-stage processes. "It's like a production line in a factory: Every step needs to be coordinated and the desired product only emerges when the steps are carried out in the right order," explains Professor Jörg Degenhardt from the Institute of Pharmacy at MLU. Instead of machines, specific biomolecules -- enzymes -- carry out this work in special glands on the surface of the leaves.

Together with researchers from Purdue University in the USA, the team in Halle decoded the individual production steps, thereby solving a decades-old mystery. "For a long time it was assumed that p-Cymene was an intermediate product of thymol and carvacrol synthesis. However, it was chemically not feasible for thymol or carvacrol to ultimately be produced from this substance," says Degenhardt. In fact, normal production of the two substances does not produce any p-Cymene at all, but rather an extremely unstable intermediate product. "This is only present for a few moments in the plant cells, which is why observing it is so difficult. However, it represents the hitherto missing step in the synthesis of the two substances," says Degenhardt. The processes start out the same for both thymol and carvacrol; only in step four do different enzymes that produce the respective substances come into play. In a fifth step, thymol and carvacrol can be further converted to thymohydroquinone and thymoquinone, which have anti-inflammatory and anti-tumour effects.

The researchers were also able to use these new findings to genetically reprogramme a species of tobacco, the model plant N. benthamiana, to produce thymol. "Even though this only happened in small quantities, it meant that we were able to fully understand the synthesis pathways and the associated enzymes," summarises Degenhardt.

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First genetic risk factors identified for sudden unexplained death in children after age one

A new study found that changes in specific genes may contribute each year to the roughly 400 sudden unexplained deaths in children (SUDC) aged one year and older -- and separately from sudden infant death syndrome (SIDS).

Children younger than 1 year old who die suddenly are diagnosed with SIDS, and older children with SUDC. But the conditions likely have many factors in common, say the study authors. Although SIDS causes 3 times as many deaths as SUDC each year, it receives more than 20 times the research funding. Parents who lost a child older than age 1 have had few options to support their search for answers, and no research organization to join.

For this reason, study author Laura Gould, after losing her daughter, Maria, to SUDC at the age of 15 months in 1997, asked NYU Langone Health neurologist Orrin Devinsky, MD , to co-found the SUDC Registry and Research Collaborative (SUDCRRC). Since 2014, registry staff have worked with bereaved parents to enroll their families in the registry, which collects and analyzes genetic specimens from parents and their deceased child. Such molecular autopsies are not currently part of the standard cause-of-death investigations conducted by most medical examiner's and coroner's offices.

Published online December 20 in the Proceedings of the National Academy of Sciences, the new study is the first to identify genetic differences present in a large group of SUDC cases, most of which involved children who died between the ages of 1 and 4.

Led by researchers from the NYU Grossman School of Medicine, the study analyzed the DNA codes of 124 sets of parents, and of the child that each couple lost to SUDC. They found that nearly 9 percent -- or 11 of the 124 children -- had DNA code changes in genes that regulate calcium function. Calcium-based signals are important for brain cell and heart muscle function. When such signals are abnormal, they may cause arrhythmias (abnormal heart rhythms) or seizures, both of which increase the risk of sudden death.

The researchers discovered that most of these DNA changes were new. The mutations were not inherited, instead arising randomly in the children of parents who did not have that genetic change, says Gould. Thus, if SUDC occurs in one child, it is unlikely to occur again if the same couple has another child. This provides some reassurance to families who want to have another child.

"Our study is the largest of its kind to date, the first to prove that there are definite genetic causes of SUDC, and the first to fill in any portion of the risk picture," says senior study author Richard Tsien, DPhil, chair of the Department of Neuroscience and Physiology and director of the Neuroscience Institute at NYU Langone. "Along with providing comfort to parents, new findings about genetic changes involved will accumulate with time, reveal the mechanisms responsible, and serve as the basis for new treatment approaches."

First Hints

"We focused on 137 genes linked by past studies to cardiac arrhythmias, epilepsy , and related conditions, because seizures and sudden cardiac death are known to be more prevalent in SUDC," says study author Dr. Devinsky, director of NYU Langone's Comprehensive Epilepsy Center. "Among the children that died, we found a tenfold greater frequency of genetic changes in these genes than in the general population."

In a partial explanation for these trends, the study's statistical analysis found that the genetic changes present in the children with SUDC occurred in clusters with similar functions, most controlling calcium channels in brain and heart muscle cells. After receiving the right signal, a cell opens the channels, enabling calcium ions to rush across membranes to create an electric current. In neurons this current triggers signals along nerve pathways, and in heart muscle cells, contractions as the heart beats.

Mutations found in the current study are known to slow calcium channel inactivation, prolong the current running through them, and potentially lead to abnormal heart rhythms that can cause the heart to stop, say the study authors. The two genes with de novo mutations in calcium processing found in more than one child in the study were RYR2 and CACNA1C, both of which are known to be linked to a cardiac arrhythmia. Other genes mutated in the SUDC group have been linked to seizures.

In addition, more than 91 percent of the children died while asleep or resting, including 50 percent of those with de novo mutations affecting genes involved with calcium physiology in the heart and brain -- CACNA1C, RYR2, CALM1, and TNNI3. Moving forward, the team plans larger studies to look at the role of neurohumoral status (sleep vs. waking, rest vs. exercise), identify more mutations that may be harmful in SUDC, and determine if the calcium channel flaws cause more dire problems in brain cells or heart muscle.

Read more at Science Daily

Are black holes and dark matter the same?

Proposing an alternative model for how the universe came to be, a team of astrophysicists suggests that all black holes -- from those as tiny as a pin head to those covering billions of miles -- were created instantly after the Big Bang and account for all dark matter.

That's the implication of a study by astrophysicists at the University of Miami, Yale University, and the European Space Agency that suggests that black holes have existed since the beginning of the universe and that these primordial black holes could be as-of-yet unexplained dark matter. If proven true with data collected from this month's launch of the James Webb Space Telescope, the discovery may transform scientific understanding of the origins and nature of two cosmic mysteries: dark matter and black holes.

"Our study predicts how the early universe would look if, instead of unknown particles, dark matter was made by black holes formed during the Big Bang -- as Stephen Hawking suggested in the 1970s," said Nico Cappelluti, an assistant professor of physics at the University of Miami and first author of the study slated for publication in The Astrophysical Journal.

"This would have several important implications," continued Cappelluti, who this year expanded the research he began at Yale as the Yale Center for Astronomy and Astrophysics Prize Postdoctoral Fellow. "First, we would not need 'new physics' to explain dark matter. Moreover, this would help us to answer one of the most compelling questions of modern astrophysics: How could supermassive black holes in the early universe have grown so big so fast? Given the mechanisms we observe today in the modern universe, they would not have had enough time to form. This would also solve the long-standing mystery of why the mass of a galaxy is always proportional to the mass of the super massive black hole in its center."

Dark matter, which has never been directly observed, is thought to be most of the matter in the universe and act as the scaffolding upon which galaxies form and develop. On the other hand, black holes, which can be found at the centers of most galaxies, have been observed. A point in space where matter is so tightly compacted, they create intense gravity.

Co-authored by Priyamvada Natarajan, professor of astronomy and physics at Yale, and Günther Hasinger, director of science at the European Space Agency (ESA), the new study suggests that so-called primordial black holes of all sizes account for all black matter in the universe.

"Black holes of different sizes are still a mystery," Hasinger explained. "We don't understand how supermassive black holes could have grown so huge in the relatively short time available since the universe existed."

Their model tweaks the theory first proposed by Hawking and fellow physicist Bernard Carr, who argued that in the first fraction of a second after the Big Bang, tiny fluctuations in the density of the universe may have created an undulating landscape with "lumpy" regions that had extra mass. These lumpy areas would collapse into black holes.

That theory did not gain scientific traction, but Cappelluti, Natarajan, and Hasinger suggest it could be valid with some slight modifications. Their model shows that the first stars and galaxies would have formed around black holes in the early universe. They also propose that primordial black holes would have had the ability to grow into supermassive black holes by feasting on gas and stars in their vicinity, or by merging with other black holes.

"Primordial black holes, if they do exist, could well be the seeds from which all the supermassive black holes form, including the one at the center of the Milky Way," Natarajan said. "What I find personally super exciting about this idea is how it elegantly unifies the two really challenging problems that I work on -- that of probing the nature of dark matter and the formation and growth of black holes -- and resolves them in one fell swoop."

Primordial black holes also may resolve another cosmological puzzle: the excess of infrared radiation, synced with X-ray radiation, that has been detected from distant, dim sources scattered around the universe. The study authors said growing primordial black holes would present "exactly" the same radiation signature.

And, best of all, the existence of primordial black holes may be proven -- or disproven -- in the near future, courtesy of the Webb telescope scheduled to launch from French Guiana before the end of the year and the ESA-led Laser Interferometer Space Antenna (LISA) mission planned for the 2030s.

Developed by NASA, ESA, and the Canadian Space Agency to succeed the Hubble Space Telescope, the Webb can look back more than 13 billion years. If dark matter is comprised of primordial black holes, more stars and galaxies would have formed around them in the early universe, which is precisely what the cosmic time machine will be able to see.

Read more at Science Daily

Could acid-neutralizing life-forms make habitable pockets in Venus’ clouds?

It's hard to imagine a more inhospitable world than our closest planetary neighbor. With an atmosphere thick with carbon dioxide, and a surface hot enough to melt lead, Venus is a scorched and suffocating wasteland where life as we know it could not survive. The planet's clouds are similarly hostile, blanketing the planet in droplets of sulfuric acid caustic enough to burn a hole through human skin.

And yet, a new study supports the longstanding idea that if life exists, it might make a home in Venus' clouds. The study's authors, from MIT, Cardiff University, and Cambridge University, have identified a chemical pathway by which life could neutralize Venus' acidic environment, creating a self-sustaining, habitable pocket in the clouds.

Within Venus' atmosphere, scientists have long observed puzzling anomalies -- chemical signatures that are hard to explain, such as small concentrations of oxygen and nonspherical particles unlike sulfuric acid's round droplets. Perhaps most puzzling is the presence of ammonia, a gas that was tentatively detected in the 1970s, and that by all accounts should not be produced through any chemical process known on Venus.

In their new study, the researchers modeled a set of chemical processes to show that if ammonia is indeed present, the gas would set off a cascade of chemical reactions that would neutralize surrounding droplets of sulfuric acid and could also explain most of the anomalies observed in Venus' clouds. As for the source of ammonia itself, the authors propose that the most plausible explanation is of biological origin, rather than a nonbiological source such as lightning or volcanic eruptions.

As they write in their study, the chemistry suggests that "life could be making its own environment on Venus."

This tantalizing new hypothesis is testable, and the researchers provide a list of chemical signatures for future missions to measure in Venus' clouds, to either confirm or contradict their idea.

"No life that we know of could survive in the Venus droplets," says study co-author Sara Seager, the Class of 1941 Professor of Planetary Sciences in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "But the point is, maybe some life is there, and is modifying its environment so that it is livable."

The study's co-authors include Janusz Petkowski, William Bains, and Paul Rimmer, who are affiliated with MIT, Cardiff University, and Cambridge University.

Life suspect

"Life on Venus" was a trending phrase last year, when scientists including Seager and her co-authors reported the detection of phosphine in the planet's clouds. On Earth, phosphine is a gas that is produced mainly through biological interactions. The discovery of phosphine on Venus leaves room for the possibility of life. Since then, however, the discovery has been widely contested.

"The phosphine detection ended up becoming incredibly controversial," Seager says. "But phosphine was like a gateway, and there's been this resurgence in people studying Venus."

Inspired to look more closely, Rimmer began combing through data from past missions to Venus. In these data, he identified anomalies, or chemical signatures, in the clouds that had gone unexplained for decades. In addition to the presence of oxygen and nonspherical particles, anomalies included unexpected levels of water vapor and sulfur dioxide.

Rimmer proposed the anomalies might be explained by dust. He argued that minerals, swept up from Venus' surface and into the clouds, could interact with sulfuric acid to produce some, though not all, of the observed anomalies. He showed the chemistry checked out, but the physical requirements were unfeasible: A massive amount of dust would have to loft into the clouds to produce the observed anomalies.

Seager and her colleagues wondered if the anomalies could be explained by ammonia. In the 1970s, the gas was tentatively detected in the planet's clouds by the Venera 8 and Pioneer Venus probes. The presence of ammonia, or NH3, was an unsolved mystery.

"Ammonia shouldn't be on Venus," Seager says. "It has hydrogen attached to it, and there's very little hydrogen around. Any gas that doesn't belong in the context of its environment is automatically suspicious for being made by life."

Livable clouds

If the team were to assume that life was the source of ammonia, could this explain the other anomalies in Venus' clouds? The researchers modeled a series of chemical processes in search of an answer.

They found that if life were producing ammonia in the most efficient way possible, the associated chemical reactions would naturally yield oxygen. Once present in the clouds, ammonia would dissolve in droplets of sulfuric acid, effectively neutralizing the acid to make the droplets relatively habitable. The introduction of ammonia into the droplets would transform their formerly round, liquid shape into more of a nonspherical, salt-like slurry. Once ammonia dissolved in sulfuric acid, the reaction would trigger any surrounding sulfur dioxide to dissolve as well.

The presence of ammonia then could indeed explain most of the major anomalies seen in Venus' clouds. The researchers also show that sources such as lightning, volcanic eruptions, and even a meteorite strike could not chemically produce the amount of ammonia required to explain the anomalies. Life, however, might.

In fact, the team notes that there are life-forms on Earth -- particuarly in our own stomachs -- that produce ammonia to neutralize and make livable an otherwise highly acidic environment.

"There are very acidic environments on Earth where life does live, but it's nothing like the environment on Venus -- unless life is neutralizing some of those droplets," Seager says.

Scientists may have a chance to check for the presence of ammonia, and signs of life, in the next several years with the Venus Life Finder Missions, a set of proposed privately funded missions, of which Seager is principal investigator, that plan to send spacecraft to Venus to measure its clouds for ammonia and other signatures of life.

Read more at Science Daily

Plants as cold specialists from the ice age

As cold relics in an increasingly warming world, plants of the spoonweed group time and again quickly adapted to a changing climate during the Ice Ages of the last two million years. An international team of evolutionary biologists and botanists led by Prof. Dr Marcus Koch of Heidelberg University used genomic analyses to study what factors favour adaptation to extreme climatic conditions. The evolutionary history of the Brassicaceae family provides insights into how plants may be able to cope with climate change in the future.

"With the challenges of increasing global warming, developing a basic understanding of how plants adapted to severe environmental change is increasingly urgent," stresses Prof. Koch, whose "Biodiversity and Plant Systematics" working group conducts research at the Centre for Organismal Studies (COS). In many cases, their evolutionary past also strongly determines the future adaptability of plants as well as their ability to develop into new forms and types, he continues. The spoonweed genus, or Latin Cochlearia, from the Brassicaceae family separated from its Mediterranean relatives more than ten million years ago. While their direct descendants specialised in response to drought stress, the spoonweeds conquered the cold and arctic habitats at the beginning of the Ice Age 2.5 million years ago.

In controlled lab experiments, the researchers studied cultivated species from both groups to determine how they repeatedly adapted during the relatively rapidly alternating cold and warm periods over the last two million years. A "cold training" indicates that the physiological adaptations to drought and salt stress during their early evolution later helped the plants develop a high tolerance to cold. Although the researchers expected that both groups would show a pronounced response to this "cold training," there appeared to be no significant difference in response to cold stress between the cold specialists of the Arctic and Alpine regions and the dry specialists or species adapted to salt water from the Mediterranean.

Furthermore, the newly emerged plants adapted to cold developed separate gene pools that frequently came into contact with one another in the cold regions. Because spoonweeds have hardly any genetic barriers to contact between species, populations with multiple sets of chromosomes developed that, subsequently, were continually reduced in their size. "Time after time, these species were then able to occupy cold ecological niches," explains Marcus Koch.

While the gene pool of the cold specialists from the Arctic expanded, the European spoonweed population has shrunk since the last Ice Age. Cold habitats in Europe are disappearing in the face of significant global warming, thus seriously endangering all spoonweed species. Only the Danish spoonweed, with its abundant sets of chromosomes, remains unscathed and in some cases is even spreading. "It is the only species of spoonweed that changed its life cycle and flourishes in salt and sand locations. In some of its ecological features, it resembles its faraway Mediterranean cousins," adds Prof. Koch. For the researchers, the physiological adaptability of the spoonweeds makes them a promising model system to simultaneously study adaptations to drought, cold, and salt stress.

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Extinct reptile discovery reveals earliest origins of human teeth, study finds

A new extinct reptile species has shed light on how our earliest ancestors became top predators by modifying their teeth in response to environmental instability around 300 million years ago.

In findings published in Royal Society Open Science, researchers at the University of Bristol have discovered that this evolutionary adaptation laid the foundations for the incisor, canine and molar teeth that all mammals -- including humans -- possess today.

Shashajaia is one of the most primitive members of a group called the Sphenacodontoidea, which includes the famous sail-backed Dimetrodon, and mammal-like reptiles known as therapsids, which eventually evolved into mammals. It is remarkable for its age and anatomy, possessing a very unique set of teeth that set it apart from other synapsids -- meaning the animal lineage that mammals belong to -- of the time.

Dr Suresh Singh of the School of Earth Sciences explained: "The teeth show clear differentiation in shape between the front and back of the jaw, organised into distinct regions. This is the basic precursor of what mammals have today -- incisors and canines up front, with molars in the back. This is the oldest record of such teeth in our evolutionary tree."

The novel dentition of Shashajaia demonstratesthat large, canine-like differentiated teeth were present in synapsids by the Late Carboniferous period -- a time famous for giant insects and the global swampy rainforests that produced much of our coal deposits.

By analytically comparing the tooth variation observed in Shashajaia with other synapsids, the study suggests that distinctive, specialised teeth likely emerged in our synapsid ancestors as a predatory adaptation to help them catch prey at a time when global climate change approximately 300 million years ago saw once-prevalent Carboniferous wetlands replaced by more arid, seasonal environments. These new, more changeable conditions brought a change in the availability and diversity of prey.

Lead author Dr Adam Huttenlocker of the University of Southern California said: "Canine-like teeth in small sphenacodonts like Shashajaia might have facilitated a fast, raptorial bite in riparian habitats where a mix of terrestrial and semi-aquatic prey could be found in abundance."

The new reptile is one of the oldest synapsids. It was named "Shashajaia bermani," which translates as Berman's bear heart, to honour the 51-year career of veteran palaeontologist, Dr David Berman of the Carnegie Museum of Natural History, as well as the local Navajo people of the discovery site within the Bears Ears National Monument, Utah.

Dr Singh said: "The study is a testament to Dr Berman who originally discovered the fossil site in 1989, and his decades of work on synapsids and other early tetrapods from the Bears Ears region of Utah which helped to justify the Bears Ears National Monument in 2016."

The site is located within an area known as the Valley of the Gods and is of huge importance to palaeontologists.

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New muscle layer discovered on the jaw

Human anatomy still has a few surprises in store for us: researchers at the University of Basel have discovered a previously overlooked section of our jaw muscles and described this layer in detail for the first time.

The masseter muscle is the most prominent of the jaw muscles. If you place your fingers on the back of your cheeks and press your teeth together, you'll feel the muscle tighten. Anatomy textbooks generally describe the masseter as consisting of one superficial and one deep part.

Now, researchers led by Dr. Szilvia Mezey from the Department of Biomedicine at the University of Basel and Professor Jens Christoph Türp from the University Center for Dental Medicine Basel (UZB) have described the structure of the masseter muscle as consisting of an additional third, even deeper layer. In the scientific journal Annals of Anatomy, they propose that this layer be given the name Musculus masseter pars coronidea -- in other words, the coronoid section of the masseter -- because the newly described layer of muscle is attached to the muscular (or "coronoid") process of the lower jaw.

The anatomical study was based on detailed examination of formalin-fixed jaw musculature, computer tomographic scans and the analysis of stained tissue sections from deceased individuals who had donated their bodies to science. This was in addition to MRI data from a living person.

As if a new animal species had been discovered

"This deep section of the masseter muscle is clearly distinguishable from the two other layers in terms of its course and function," explains Mezey. The arrangement of the muscle fibers, she says, suggests that this layer is involved in the stabilization of the lower jaw. It also appears to be the only part of the masseter that can pull the lower jaw backwards -- that is, toward the ear.

A look at historical anatomy studies and textbooks reveals that the structure of the masseter muscle has already raised questions in the past. In a previous edition of Gray's Anatomy, from the year 1995, the editors also describe the masseter muscle as having three layers, although the cited studies were based on the jaw musculature of other species and partly contradicted one another.

Other individual studies from the early 2000s also reported three layers, but they divided the superficial section of the masseter into two layers and agreed with standard works in their description of the deeper section.

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Sauropod dinosaurs were restricted to warmer regions of Earth

Giant, long-necked sauropods, thought to include the largest land animals ever to have existed, preferred to live in warmer, more tropical regions on Earth, suggesting they may have had a different physiology from other dinosaurs, according to a new study led by researchers at UCL and the University of Vigo.

The study, published in the journal Current Biology, investigated the enigma of why sauropod fossils are only found at lower latitudes, while fossils of other main dinosaur types seem ubiquitously present, with many located in the polar regions.

The researchers analysed the fossil record across the Mesozoic era (the time of the dinosaurs), lasting from around 230 to 66 million years ago, looking at occurrences of fossils of the three main dinosaur types: sauropods, which include the Brontosaurus and the Diplodocus, theropods ("lizard-hipped"), which include velociraptors and Tyrannosaurus rex, and ornithischians ("bird-hipped") such as the Triceratops.

Combining this fossil data with data about climate throughout the period, along with information about how continents have moved across the globe, the researchers concluded that sauropods were restricted to warmer, drier habitats than other dinosaurs. These habitats were likely to be open, semi-arid landscapes, similar to today's savannahs.

Co-author Dr Philip Mannion (UCL Earth Sciences) said: "Our research shows that some parts of the planet always seemed to be too cold for sauropods. They seem to have avoided any temperatures approaching freezing. Other dinosaur types, in contrast, could thrive in Earth's polar regions, from innermost Antarctica to polar Alaska -- which, due to the warmer climate, were ice-free, with lush vegetation.

"This suggests sauropods had different thermal requirements from other dinosaurs, relying more on their external environment to heat their bodies -- slightly closer to being 'cold-blooded', like modern-day reptiles. Their grand size hints that this physiology may have been unique."

First author Dr Alfio Alessandro Chiarenza, formerly of UCL who is now based at the University of Vigo, Spain, said: "It may be that sauropods were physiologically incapable of thriving in colder regions, or that they thrived less well in these areas than their dinosaurian cousins and were outcompeted.

"A mix of features may have helped sauropods shed heat more easily than mammals do today. Their long necks and tails would have given them a larger surface area, and they may have had a respiratory system more akin to birds, which is much more efficient.

"Some species of theropods and ornithischians are known to have had feathers or downy fur helping them retain body warmth. This suggests they may have generated their own body heat. For sauropods, however, there is no evidence of this kind of insulation.

"Sauropods' strategies for keeping their eggs warm may also have differed from the other dinosaurs. Theropods probably warmed eggs by sitting on them, whereas ornithischians seem to have used heat generated by decaying plants. Sauropods, meanwhile, may have buried their eggs, relying on heat from the sun and the ground."

In their paper, the researchers noted that the fossil record showed zero occurrences of sauropods above a latitude of 50 degrees north -- an area encompassing most of Canada, Russia, northern Europe and the UK -- or below 65 degrees south, encompassing Antarctica. In contrast, there are rich records for theropods and ornithischians living above 50 degrees north in later periods (from 145 million years ago).

To test if this was a true reflection of where sauropods lived, researchers used a statistical technique to adjust for gaps in the fossil record, and also analysed where the highest diversities of dinosaur types were in different periods throughout the Mesozoic era.

They combined fossil data with climate data, allowing an estimate of the temperature ranges of the dinosaur types' habitats, finding that sauropods' range across the latitudes was more restricted during colder periods.

They then used habitat modelling to infer which regions of the globe would likely be suitable for sauropods and the other dinosaur types to live.

While in the past it was believed that dinosaurs were ectothermic ("cold-blooded"), like reptiles today, relying on the external environment to heat their bodies, it is now thought they were closer to "warm-blooded" mammals, generating some of their own body heat (endothermic).

Read more at Science Daily