Pioneering new research has helped geologists solve a long-standing puzzle that could help pinpoint new, untapped concentrations of some the most valuable rare earth deposits. Credit: Michael Anenburg, ANU.
Pioneering new research has helped geologists solve a long-standing puzzle that could help pinpoint new, untapped concentrations of some the most valuable rare earth deposits.
A team of geologists, led by Professor Frances Wall from the Camborne School of Mines, have discovered a new hypothesis to predict where rare earth elements neodymium and dysprosium could be found.
The elements are among the most sought after, because they are an essential part of digital and clean energy manufacturing, including magnets in large wind turbines and electric cars motors.
For the new research, scientists conducted a series of experiments that showed sodium and potassium — rather than chlorine or fluorine as previously thought — were the key ingredients for making these rare earth elements soluble.
This is crucial as it determines whether they crystalise — making them fit for extraction — or stayed dissolved in fluids.
The experiments could therefore allow geologists to make better predictions about where the best concentrations of neodymium and dysprosium are likely to be found.
The results are published in the journal, Science Advances on Friday, October 9th 2020.
University of Exeter researchers, through the ‘SoS RARE’ project, have previously studied many natural examples of the roots of very unusual extinct carbonatite volcanoes, where the world’s best rare earth deposits occur, in order to try and identify potential deposits of the rare earth minerals.
However, in order to gain a greater insight into their results, they invited Michael Anenburg to join the team to carry out experiments at the Australian National University (ANU).
He simulated the crystallisation of molten carbonate magma to find out which elements would be concentrated in the hot waters left over from the crystallisation process.
It showed that sodium and potassium make the rare earths soluble in solution. Without sodium and potassium, rare earth minerals precipitate in the carbonatite itself. With sodium, intermediate minerals like burbankite form and are then replaced. With potassium, dysprosium is more soluble than neodymium and carried out to the surrounding rocks.
Professor Frances Wall, leader of the SoS RARE project said: “This is an elegant solution that helps us understand better where ‘heavy’ rare earths like dysprosium and ‘light’ rare earths like neodymium’ may be concentrated in and around carbonatite intrusions. We were always looking for evidence of chloride-bearing solutions but failing to find it. These results give us new ideas.”
Michael Anenburg , a Postdoctoral Fellow at ANU said: “My tiny experimental capsules revealed minerals that nature typically hides from us. It was a surprise how well they explain what we see in natural rocks and ore deposits.”
Reference:
Michael Anenburg, John A. Mavrogenes, Corinne Frigo and Frances Wall. Rare earth element mobility in and around carbonatites controlled by sodium, potassium, and silica. Science Advances, 2020 DOI: 10.1126/sciadv.abb6570
Micro-CT reconstruction of Mysteriomorphus pelevini Credit: D. Peris & R. Kundrata et al. / Scientific Reports
About a year ago, researchers found fossil specimens of beetles in an amber deposit in Myanmar, thereby describing a new beetle family that lived about 99 million years ago. However, the scientists had not been able to fully describe the morphology of the insects in the amber sample, which is why the beetles were subsequently given the mysterious name Mysteriomorphidae. An international research team led by the University of Bonn (Germany) and Palacky University (Czech Republic) has now examined four newly found specimens of the Mysteriomorphidae using computer tomography and has been able to reconstruct them. The results allow to draw conclusions about the evolution of the species during the Cretaceous period. The study has been published in the journal Scientific Reports.
Small creatures enclosed in amber can provide scientists with important information about past times, some of which date back many millions of years. In January 2019, the Spanish paleontologist Dr. David Peris, one of the two main authors of the study, collected several amber samples from the northern state of Kachin in Myanmar during a scientific trip to China and found beetle specimens from the same group as the Mysteriomorphidae.
Some of the newly found specimens showed a very good state of preservation – a good prerequisite for David Peris and his colleagues to carry out a virtual reconstruction of one of the beetles using computer tomography (CT scan). The technique used in paleontology allows researchers to study many small features of the fossils – even internal structures such as genitalia, if preserved.
While David Peris and his colleagues started to study and describe the morphology, i.e. the outer shape of the beetles, another research group also described the new family of Mysteriomorphidae by means of further specimens, that also came from the amber deposit in Myanmar. “However, the first study left some open questions about the classification of these fossils which had to be answered. We used the opportunity to pursue these questions with new technologies,” explains David Peris, researcher now at the Institute for Geosciences and Meteorology at the University of Bonn.
“We used the morphology to better define the placement of the beetles and discovered that they were very closely related to Elateridae, a current family,” explains Dr. Robin Kundrata from Palacky University, the second main author of the study and also an expert on this group of beetles. The scientists discovered important diagnostic characters that these beetle lineages share on mouthparts, thorax and abdomen.
Analysis of the evolution of beetles
Apart from the morphology, the researchers also analyzed the evolutionary history of the beetles. Earlier models had suggested that the beetles had a low extinction rate throughout their long evolutionary history, even during the Cretaceous period. However, the researchers provided a list of fossil groups of beetles described from the Cretaceous amber findings that, as Mysteriomorphidae, are only known as fossils from that time and had not survived the end of the Cretaceous period.
Background: During the Cretaceous period, flowering plants spread all over the world, replacing the old plants in the changing environment. This distribution of plants was connected with new possibilities for many associated animals and also with the development of new living beings, for example pollinators of flowers. However, most previous theories had not described that the animal species that were previously well adapted to the old plants were under pressure to adapt to the new resources and possibly became extinct. “Our results support the hypothesis that beetles, but perhaps some other groups of insects, suffered a decrease in their diversity during the time of plant revolution,” states David Peris.
Reference:
David Peris, Robin Kundrata, Xavier Delclòs, Bastian Mähler, Michael A. Ivie, Jes Rust, Conrad C. Labandeira. Unlocking the mystery of the mid-Cretaceous Mysteriomorphidae (Coleoptera: Elateroidea) and modalities in transiting from gymnosperms to angiosperms. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-73724-7
Fossil and life reconstruction of Juravenator, a small carnivorous dinosaur from the Jurassic of Germany. The arrow points to the sensory organ, which are found on polygonal scales covering the lower part of the tail. Credit: Jake Baardse.
Paleontologists have discovered remarkable evidence of the sensory capabilities in the fossilized skin of a 155-million-year-old carnivorous dinosaur.
The juvenile dinosaur, named Juravenator, comes from the Jurassic of Germany and is perfectly preserved from nose to tail, including remains of its scaly skin and other soft tissues.
Dr. Phil Bell, from the Palaeoscience Research Center at the University of New England in Armidale, Australia, is a leading researcher in the study of dinosaur skin. “Few people pay much attention to dinosaur skin, because it is assumed that they are just big, scaly reptiles,” he said. “But when I looked closely at the scales on the side of the tail, I kept finding these little ring-like features that didn’t make sense; they were certainly unlike other dinosaur scales.”
The researchers found that the ring-like features were very similar to special sensory nodes found on the scales of modern crocodiles. These nodes, called integumentary sense organs (ISOs), are responsive to touch, chemistry, and temperature information, providing crocodiles with important sensory from their surroundings.
Dinosaur specialist Dr. Christophe Hendrickx, from the Unidad Ejecutora Lillo in San Miguel de Tucumán, Argentina, who co-authored the study points out, “very little in known about dinosaur sensory organs. Sensory scales were recently assumed to be present on the snout of tyrannosaurs like T. rex based on the texture of their facial bones, but this is the first direct evidence of their presence in a dinosaur.”
Because crocodiles are aquatic predators, the researchers also speculated that Juravenator too might have hunted fish and other aquatic animals. Whereas alligators only have ISOs on the face, crocodiles have ISOs all over the body, including the tail. Although the skin on other parts of the body of Juravenator is unknown, it may have submerged its tail to detect the movement of prey underwater.
The study was published in the journal Current Biology.
Reference:
Bell, P.R. and Hendrickx, C. 2020. Crocodile-like sensory scales in a Late Jurassic theropod dinosaur. Current Biology 30: doi.org/10.1016/j.cub.2020.08.066
The debate about when dinosaurs developed feathers has taken a new turn with a paper refuting earlier claims that feathers were also found on dinosaurs’ relatives, the flying reptiles called pterosaurs.
Pterosaur expert Dr David Unwin from the University of Leicester’s Centre for Palaeobiology Research, and Professor Dave Martill, of the University of Portsmouth have examined the evidence that these creatures had feathers and believe they were in fact bald.
They have responded to a suggestion by a group of his colleagues led by Zixiao Yang that some pterosaur fossils show evidence of feather-like branching filaments, ‘protofeathers’, on the animal’s skin.
Dr Yang, from Nanjing University, and colleagues presented their argument in a 2018 paper in the journal Nature Ecology and Evolution. Now Unwin and Martill, have offered an alternative, non-feather explanation for the fossil evidence in the same journal.
While this may seem like academic minutiae, it actually has huge palaeontological implications. Feathered pterosaurs would mean that the very earliest feathers first appeared on an ancestor shared by both pterosaurs and dinosaurs, since it is unlikely that something so complex developed separately in two different groups of animals.
This would mean that the very first feather-like elements evolved at least 80 million years earlier than currently thought. It would also suggest that all dinosaurs started out with feathers, or protofeathers but some groups, such as sauropods, subsequently lost them again — the complete opposite of currently accepted theory.
The evidence rests on tiny, hair-like filaments, less than one tenth of a millimetre in diameter, which have been identified in about 30 pterosaur fossils. Among these, Yang and colleagues were only able to find just three specimens on which these filaments seem to exhibit a ‘branching structure’ typical of protofeathers.
Unwin and Martill propose that these are not protofeathers at all but tough fibres which form part of the internal structure of the pterosaur’s wing membrane, and that the ‘branching’ effect may simply be the result of these fibres decaying and unravelling.
Dr Unwin said: “The idea of feathered pterosaurs goes back to the nineteenth century but the fossil evidence was then, and still is, very weak. Exceptional claims require exceptional evidence — we have the former, but not the latter.”
Professor Martill noted that either way, palaeontologists will have to carefully reappraise ideas about the ecology of these ancient flying reptiles. He said, “If they really did have feathers, how did that make them look, and did they exhibit the same fantastic variety of colours exhibited by birds. And if they didn’t have feathers, then how did they keep warm at night, what limits did this have on their geographic range, did they stay away from colder northern climes as most reptiles do today. And how did they thermoregulate? The clues are so cryptic, that we are still a long way from working out just how these amazing animals worked.”
The paper “No protofeathers on pterosaurs” is published this week in Nature Ecology and Evolution.
Reference:
David M. Unwin, David M. Martill. No protofeathers on pterosaurs. Nature Ecology & Evolution, 2020; DOI: 10.1038/s41559-020-01308-9
Artist’s impression of Oksoko avarsan dinosaurs (credit: Michael Skrepnick)
A newly discovered species of toothless, two-fingered dinosaur has shed light on how a group of parrot-like animals thrived more than 68 million years ago.
The unusual species had one less finger on each forearm than its close relatives, suggesting an adaptability which enabled the animals to spread during the Late Cretaceous Period, researchers say.
Multiple complete skeletons of the new species were unearthed in the Gobi Desert in Mongolia by a University of Edinburgh-led team.
Dinosaur family
Named Oksoko avarsan, the feathered, omnivorous creatures grew to around two metres long and had only two functional digits on each forearm. The animals had a large, toothless beak similar to the type seen in species of parrot today.
The remarkably well-preserved fossils provided the first evidence of digit loss in the three-fingered family of dinosaurs known as oviraptors.
The discovery that they could evolve forelimb adaptations suggests the group could alter their diets and lifestyles, and enabled them to diversify and multiply, the team says.
Finger loss
Researchers studied the reduction in size, and eventual loss, of a third finger across the oviraptors’ evolutionary history. The group’s arms and hands changed drastically in tandem with migrations to new geographic areas — specifically to what is now North America and the Gobi Desert.
The team also discovered that Oksoko avarsan — like many other prehistoric species — were social as juveniles. The fossil remains of four young dinosaurs were preserved resting together.
The study, published in the journal Royal Society Open Science, was funded by The Royal Society and the Natural Sciences and Engineering Council of Canada. It also involved researchers from the University of Alberta and Philip J. Currie Dinosaur Museum in Canada, Hokkaido University in Japan, and the Mongolian Academy of Sciences.
Dr Gregory Funston, of the University of Edinburgh’s School of GeoSciences, who led the study, said: “Oksoko avarsan is interesting because the skeletons are very complete and the way they were preserved resting together shows that juveniles roamed together in groups. But more importantly, its two-fingered hand prompted us to look at the way the hand and forelimb changed throughout the evolution of oviraptors — which hadn’t been studied before. This revealed some unexpected trends that are a key piece in the puzzle of why oviraptors were so diverse before the extinction that killed the dinosaurs.”
Reference:
Gregory F. Funston, Tsogtbaatar Chinzorig, Khishigjav Tsogtbaatar, Yoshitsugu Kobayashi, Corwin Sullivan, Philip J. Currie. A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria. Royal Society Open Science, 2020; 7 (10): 201184 DOI: 10.1098/rsos.201184
Representative Image : An artist’s rendering of Colobops noviportensis, a new species of reptile from prehistoric Connecticut. Credit: Michael Hanson
Challenging a 75-year-old notion about how and when reptiles evolved during the past 300 million-plus years involves a lot of camerawork, loads of CT scanning, and, most of all, thousands of miles of travel. Just check the stamps in Tiago R. Simões ‘ passport.
Simões is the Alexander Agassiz Postdoctoral Fellow in the lab of Harvard paleontologist Stephanie Pierce. From 2013 to 2018, he traveled to more than 20 countries and more than 50 different museums to take CT scans and photos of nearly 1,000 reptilian fossils, some hundreds of millions of years old. It amounted to about 400 days of active collection, helping form what is believed to be the largest available timeline on the evolution of major living and extinct reptile groups.
Now, a statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts. The findings are described in a recently published paper in Nature Communications.
In it, researchers show that the evolution of extinct lineages of reptiles from more than 250 million years ago took place through many small bursts of morphological changes, such as developing armored body plans or wings for gliding, over a period of 50 million years instead of during a single major evolutionary event, as previously thought. They also show that the early evolution of most lizard lineages was a continuously slower and more incremental process than previously understood.
“It wasn’t a sudden jump that kind of established the wide diversity that we see today in reptiles,” Simões said. “There was an initial jump, but relatively small, and then a sustained increase over time of those rates [of evolution] and different diversity values.”
Evidence of this has been seen in other types of animals, but this is the first time it’s been seen in reptiles — one of the most diverse animals on the planet, with more than 10,000 different species and a dizzying variety of abilities and traits. Consider how some lizard species can freeze solid overnight then thaw the next morning, or how turtles grow protective armor.
The findings run contrary to the evolutionary theory of adaptive radiation that Harvard paleontologist George G. Simpson popularized in the 1940s, which sought to explain the origins of the planet’s biological diversity. Adaptive radiation has been the focus of intense investigation for decades, but wasn’t until recent years that the technology, methods, and data have existed to precisely measure rapid rates of evolution in the fossil record in terms of different animal species, morphologies, and at the molecular level using DNA.
Researchers of this study also included Pierce, the Thomas D. Cabot Associate Professor of Organismic and Evolutionary Biology and curator of vertebrate paleontology in the Museum of Comparative Zoology; Oksana Vernygora, a graduate student from the University of Alberta in Canada; and Professor Michael Wayne Caldwell at Alberta.
Simões traveled to almost all of the world’s major natural history museums to collect the data for the study, including the national natural history museums in London, Paris, Berlin, Ottawa, Beijing, and Tokyo. In the U.S., he visited the Smithsonian National Museum of Natural History, the Carnegie Museum of Natural History, and Harvard’s Museum of Comparative Zoology.
The scientists believe that by understanding how animals evolve over longer periods of time, they can glean a number of lessons on ecology and how organisms are affected by environmental changes. Using the database, researchers can determine when major reptile lineages or morphologies originated, see how those changes affected reptile DNA, and learn important lessons about how species were impacted by historical events.
Reptiles, for instance, have survived three major mass extinction events. The biggest was the Permian–Triassic mass extinction about 250 million years ago that killed about 90 percent of the planet’s species, earning it the moniker the Great Dying. It’s believed to have been caused by a buildup of natural greenhouse gases.
The timeline researchers created found that the rates at which reptiles were evolving and the anatomical differences among them before the Great Dying were nearly as high as after the event. However, it was only much after the Great Dying that reptiles became dominant in many ecosystems and extremely diverse in terms of the number of different species.
That finding cemented that fast rates of anatomical change don’t need to coincide with genetic diversity or an abundance of species (called taxonomic diversity), and further rebutted adaptive radiation as the only explanation for the origin of new animal groups and body plans. The researchers also note that it took reptiles almost 10 million years to recover to previous levels of anatomical diversity.
“That kind of tells you on the broad scheme of things and on a global scale how much impact, throughout the history of life, sudden environmental changes may have,” Simões said.
Further evidence that contradicted adaptive radiation included similar but surprising findings on the origins of snakes, which achieved the major aspects of their skinny, elongated body plans early in their evolution about 170 million years ago (but didn’t fully lose their limbs for another 105 million years). They also underwent rapid changes to their skulls about 170 to 165 million years ago that led to such powerful and flexible mouths that today they can swallow whole prey many times their size. But while snakes experienced the fastest rates of anatomical change in the history of reptile evolution, these changes did not coincide with increases in taxonomic diversity or high rates of molecular evolution as predicted by adaptive radiations, the researchers said.
The scientists weren’t able to pinpoint why this mismatch happens, and suggested more research is needed. In particular they want to understand how body plans evolve and how changes in DNA relate to it.
“We can see better now what are the big changes in the history of life and especially in the history of reptile life on Earth,” Simões said. “We will keep digging.”
Reference:
Tiago R. Simões, Oksana Vernygora, Michael W. Caldwell, Stephanie E. Pierce. Megaevolutionary dynamics and the timing of evolutionary innovation in reptiles. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-17190-9
Note: The above post is reprinted from materials provided by Harvard University. Original written by Juan Siliezar.
Altmühl specimen of Archaeopteryx, showing the dorsal surface of the right wing. (a) Key anatomical features denoted include two slightly curved rachis impressions (white arrows), two leading vane widths (small double arrows), the leading edge of the best-preserved UMPC (arrowhead), and a representative barb angle, which measures 25.1° (yellow lines; corresponding barb in isolated feather measures 25.2°; see Supplementary Fig. S15). Also note the posterior orientation of the UMPCs with respect to the manus and primaries, suggesting an absence of S-shaped centerlines. Inset: overview of specimen, denoting enlarged region. (b) Reconstruction of the isolated feather is overlaid at scale. Note the match in both size and shape to the underlying distal UMPC in the Altmühl specimen. Inset: black feather denotes prior hypothesis of the isolated feather’s approximate location, as a distal member of the UMPC tract9 (shown as a right wing to match that of the Altmühl specimen). Scale bar: 1 cm.
A new study provides substantial evidence that the first fossil feather ever to be discovered does belong to the iconic Archaeopteryx, a bird-like dinosaur named in Germany on this day in 1861. This debunks a recent theory that the fossil feather originated from a different species.
The research published in Scientific Reports finds that the Jurassic fossil matches a type of wing feather called a primary covert. Primary coverts overlay the primary feathers and help propel birds through the air. The international team of scientists led by the University of South Florida analyzed nine attributes of the feather, particularly the long quill, along with data from modern birds. They also examined the 13 known skeletal fossils of Archaeopteryx, three of which contain well-preserved primary coverts. The researchers discovered that the top surface of an Archaeopteryx wing has primary coverts that are identical to the isolated feather in size and shape. The isolated feather was also from the same fossil site as four skeletons of Archaeopteryx, confirming their findings.
“There’s been debate for the past 159 years as to whether or not this feather belongs to the same species as the Archaeopteryx skeletons, as well as where on the body it came from and its original color,” said lead author Ryan Carney, assistant professor of integrative biology at USF. “Through scientific detective work that combined new techniques with old fossils and literature, we were able to finally solve these centuries-old mysteries.”
Using a specialized type of electron microscope, the researchers determined that the feather came from the left wing. They also detected melanosomes, which are microscopic pigment structures. After refining their color reconstruction, they found that the feather was entirely matte black, not black and white as another study has claimed.
Carney’s expertise on Archaeopteryx and diseases led to the National Geographic Society naming him an “Emerging Explorer,” an honor that comes with a $10,000 grant for research and exploration. He also teaches a course at USF, called “Digital Dinosaurs.” Students digitize, animate and 3D-print fossils, providing valuable experience in paleontology and STEAM fields.
Reference:
Ryan M. Carney, Helmut Tischlinger, Matthew D. Shawkey. Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-65336-y
Soldiers remove bricks from the road after earthquake in Rongxian county on 25 February 2019. | Credit: IC
An unusually shallow earthquake triggered by hydraulic fracturing in a Chinese shale gas field could change how experts view the risks of fracking for faults that lie very near the Earth’s surface.
In the journal Seismological Research Letters, Hongfeng Yang of The Chinese University of Hong Kong and colleagues suggest that the magnitude 4.9 earthquake that struck Rongxian County, Sichuan, China on 25 February 2019 took place along a fault about one kilometer (0.6 miles) deep.
The earthquake, along with two foreshocks with magnitudes larger than 4, appear to be related to activity at nearby hydraulic fracturing wells. Although earthquakes induced by human activity such as fracking are typically more shallow than natural earthquakes, it is rare for any earthquake of this size to take place at such a shallow depth.
“Earthquakes with much smaller magnitudes, for example magnitude 2, have been reported at such shallow depths. They are understood by having small scale fractures in such depths that can slip fast,” said Yang. “However, the dimensions of earthquakes are scale-dependent. Magnitude 4 is way bigger than magnitude 2 in term of rupture length and width, and thus needs a sizeable fault as the host.”
“The results here certainly changed our view in that a shallow fault can indeed slip seismically,” he added. “Therefore, we should reconsider our strategies of evaluating seismic risk for shallow faults.”
Two people died and twelve were injured in the 25 February earthquake, and the economic loss due to the event has been estimated at 14 million RMB, or about $2 million. There have been few historic earthquakes in the region, and before 2019 there had been no earthquakes larger than magnitude 3 on the fault where the main earthquake took place.
Since 2018, there have been at least 48 horizontal fracking wells drilled from 13 well pads in the region, with three well pads less than two kilometers (1.2 miles) from the Molin fault, where the main earthquake took place.
Yang and his colleagues located the earthquakes and were able to calculate the length of the main rupture using local and regional seismic network data, as well as InSAR satellite data.
It is unusual to see clear satellite data for a small earthquake like this, Yang said. “InSAR data are critical to determine the depth and accurate location of the mainshock, because the ground deformation was clearly captured by satellite images,” he noted. “Given the relatively small size of the mainshock, it would not be able to cause deformation above the ‘noise’ level of satellite data if it were deeper than about two kilometers.”
The two foreshocks took place on a previously unmapped fault in the area, the researchers found, underscoring how difficult it can be to prevent fracking-induced earthquakes in an area where fault mapping is incomplete.
The researchers note that the Molin fault is separated from the geologic formation where fracking took place by a layer of shale about 800 meters (2625 feet) thick. The separating layer sealed off the fault from fracking fluids, so it is unlikely that the pressures of fluid injected into rock pores around the fault caused the fault to slip. Instead, Yang and colleagues suggest that changes in elastic stress in rock may have triggered the main earthquake on the Molin fault, which was presumed to be stable.
“The results here certainly pose a significant concern: we cannot ignore a shallow fault that was commonly thought to be aseismic,” Yang said, who said more public information on fracking injection volume, rate and duration could help calculate safe distances for well placement in the future.
Reference:
Hongfeng Yang, Pengcheng Zhou, Nan Fang, Gaohua Zhu, Wenbin Xu, Jinrong Su, Fanbao Meng, Risheng Chu. A Shallow Shock: The 25 February 2019 ML 4.9 Earthquake in the Weiyuan Shale Gas Field in Sichuan, China. Seismological Research Letters, 2020; DOI: 10.1785/0220200202
A skeletal mount of the mosasaur ‘Gnathomortis stadtmani’ at BYU’s Eyring Science Center. USU Eastern paleontologist Josh Lively named the giant marine lizard that roamed the oceans of North America toward the end of the Age of Dinosaurs. Courtesy BYU.
Some 92 to 66 million years ago, as the Age of Dinosaurs waned, giant marine lizards called mosasaurs roamed an ocean that covered North America from Utah to Missouri and Texas to the Yukon. The air-breathing predators were streamlined swimmers that devoured almost everything in their path, including fish, turtles, clams and even smaller mosasaurs.
Coloradoan Gary Thompson discovered mosasaur bones near the Delta County town of Cedaredge in 1975, which the teen reported to his high school science teacher. The specimens made their way to Utah’s Brigham Young University, where, in 1999, the creature that left the fossils was named Prognathodon stadtmani.
“I first learned of this discovery while doing background research for my Ph.D.,” says newly arrived Utah State University Eastern paleontologist Joshua Lively, who recently took the reins as curator of the Price campus’ Prehistoric Museum. “Ultimately, parts of this fossil, which were prepared since the original description in 1999, were important enough to become a chapter in my 2019 doctoral dissertation.”
Upon detailed research of the mosasaur’s skeleton and a phylogenetic analysis, Lively determined the BYU specimen is not closely related to other species of the genus Prognathodon and needed to be renamed. He reclassified the mosasaur as Gnathomortis stadtmani and reports his findings in the most recent issue of the Journal of Vertebrate Paleontology.
His research was funded by the Geological Society of America, the Evolving Earth Foundation, the Texas Academy of Science and the Jackson School of Geosciences at The University of Texas at Austin.
“The new name is derived from Greek and Latin words for ‘jaws of death,'” Lively says. “It was inspired by the incredibly large jaws of this specimen, which measure four feet (1.2 meters) in length.”
An interesting feature of Gnathomortis’ mandibles, he says, is a large depression on their outer surface, similar to that seen in modern lizards, such as the Collared Lizard. The feature is indicative of large jaw muscles that equipped the marine reptile with a formidable biteforce.
“What sets this animal apart from other mosasaurs are features of the quadrate — a bone in the jaw joint that also forms a portion of the ear canal,” says Lively, who returned to the fossil’s Colorado discovery site and determined the age interval of rock, in which the specimen was preserved.
“In Gnathomortis, this bone exhibits a suite of characteristics that are transitional from earlier mosasaurs, like Clidastes, and later mosasaurs, like Prognathodon. We now know Gnathomortis swam in the seas of Colorado between 79 and 81 million years ago, or at least 3.5 million years before any species of Prognathodon.”
He says fossil enthusiasts can view Gnathomortis’ big bite at the BYU Museum of Paleontology in Provo, Utah, and see a cast of the skull at the Pioneer Town Museum in Cedaredge, Colorado. Reconstructions of the full skeleton are on display at the John Wesley Powell River History Museum in Green River, Utah, and in BYU’s Eyring Science Center.
“I’m excited to share this story, which represents years of effort by many citizen scientists and scholars, as I kick off my new position at USU Eastern’s Prehistoric Museum,” Lively says. “It’s a reminder of the power of curiosity and exploration by people of all ages and backgrounds.”
Reference:
Joshua R. Lively. Redescription and phylogenetic assessment of ‘Prognathodon’ stadtmani: implications for Globidensini monophyly and character homology in Mosasaurinae. Journal of Vertebrate Paleontology, 2020; e1784183 DOI: 10.1080/02724634.2020.1784183
Note: The above post is reprinted from materials provided by Utah State University. Original written by Mary-Ann Muffoletto.
Artist’s impression of Spinosaurus. Credit: Davide Bonadonna
A discovery of more than a thousand dinosaur teeth, by a team of researchers from the University of Portsmouth, proves beyond reasonable doubt that Spinosaurus, the giant predator made famous by the movie Jurassic Park III as well as the BBC documentary Planet Dinosaur was an enormous river-monster.
Research published today in the journal Cretaceous Research proves that Spinosaurus aegyptiacus, a 15 metre long, six-tonne beast was in fact the most commonly found creature in the Kem Kem river system, which flowed through the Sahara Desert 100 million years ago.
Until recently it was believed that dinosaurs lived exclusively on land. However, research published earlier this year showed that Spinosaurus was well adapted to an aquatic lifestyle, due to its newly discovered tail. This latest research of 1,200 teeth found in the same region further supports this theory.
Scientists from the University of Portsmouth collected the fossilised remains from the site of an ancient river bed in Morocco. After analysing all of them it was discovered there was an abundance of Spinosaurus teeth, which are distinct and easily identifiable.
David Martill, Professor of Palaeobiology at the University of Portsmouth, said:
“The huge number of teeth we collected in the prehistoric river bed reveals that Spinosaurus was there in huge numbers, accounting for 45 per cent of the total dental remains. We know of no other location where such a mass of dinosaur teeth have been found in bone-bearing rock.
“The enhanced abundance of Spinosaurus teeth, relative to other dinosaurs, is a reflection of their aquatic lifestyle. An animal living much of its life in water is much more likely to contribute teeth to the river deposit than those dinosaurs that perhaps only visited the river for drinking and feeding along its banks.
“From this research we are able to confirm this location as the place where this gigantic dinosaur not only lived but also died. The results are fully consistent with the idea of a truly water-dwelling, “river monster.” ”
Professor Martill worked alongside two students studying for their Masters Degree in Paleontology at the University of Portsmouth.
Thomas Beevor said: “The Kem Kem river beds are an amazing source of Spinosaurus remains. They also preserve the remains of many other Cretaceous creatures including sawfish, coelacanths, crocodiles, flying reptiles and other land-living dinosaurs. With such an abundance of Spinosaurus teeth, it is highly likely that this animal was living mostly within the river rather than along its banks.”
Aaron Quigley, explained the process of sorting through the teeth: “After preparing all the fossils, we then assessed each one in turn. The teeth of Spinosaurus have a distinct surface. They have a smooth round cross section which glints when held up to the light. We sorted all 1200 teeth into species and then literally counted them all up. Forty-five per cent of our total find were Spinosaurus teeth.”
Reference:
Thomas Beevor, Aaron Quigley, Roy E. Smith, Robert S.H. Smyth, Nizar Ibrahim, Samir Zouhri, David M. Martill. Taphonomic evidence supports an aquatic lifestyle for Spinosaurus. Cretaceous Research, 2021; 117: 104627 DOI: 10.1016/j.cretres.2020.104627
Earthquakes can be abrupt bursts of home-crumbling, ground-buckling energy when slices of the planet’s crust long held in place by friction suddenly slip and lurch.
“We typically think of the plates on either side of a fault moving, deforming, building up stresses and then: Boom, an earthquake happens,” said Stanford University geophysicist Eric Dunham.
But deeper down, these blocks of rock can slide steadily past one another, creeping along cracks in Earth’s crust at about the rate that your fingernails grow.
A boundary exists between the lower, creeping part of the fault, and the upper portion that may stand locked for centuries at a stretch. For decades, scientists have puzzled over what controls this boundary, its movements and its relationship with big earthquakes. Chief among the unknowns is how fluid and pressure migrate along faults, and how that causes faults to slip.
A new physics-based fault simulator developed by Dunham and colleagues provides some answers. The model shows how fluids ascending by fits and starts gradually weaken the fault. In the decades leading up to big earthquakes, they seem to propel the boundary, or locking depth, a mile or two upward.
Migrating swarms
The research, published Sept. 24 in Nature Communications, also suggests that as pulses of high-pressure fluids draw closer to the surface, they can trigger earthquake swarms — strings of quakes clustered in a local area, usually over a week or so. Shaking from these seismic swarms is often too subtle for people to notice, but not always: A swarm near the southern end of the San Andreas Fault in California in August 2020, for example, produced a magnitude-4.6 quake strong enough to rattle surrounding cities.
Each of the earthquakes in a swarm has its own aftershock sequence, as opposed to one large mainshock followed by many aftershocks. “An earthquake swarm often involves migration of these events along a fault in some direction, horizontally or vertically,” explained Dunham, senior author of the paper and an associate professor of geophysics at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).
The simulator maps out how this migration works. Whereas much of the advanced earthquake modeling of the last 20 years has focused on the role of friction in unlocking faults, the new work accounts for interactions between fluid and pressure in the fault zone using a simplified, two-dimensional model of a fault that cuts vertically through Earth’s entire crust, similar to the San Andreas Fault in California.
“Through computational modeling, we were able to tease out some of the root causes for fault behavior,” said lead author Weiqiang Zhu, a graduate student in geophysics at Stanford. “We found the ebb and flow of pressure around a fault may play an even bigger role than friction in dictating its strength.”
Underground valves
Faults in Earth’s crust are always saturated with fluids — mostly water, but water in a state that blurs distinctions between liquid and gas. Some of these fluids originate in Earth’s belly and migrate upwards; some come from above when rainfall seeps in or energy developers inject fluids as part of oil, gas or geothermal projects. “Increases in the pressure of that fluid can push out on the walls of the fault, and make it easier for the fault to slide,” Dunham said. “Or, if the pressure decreases, that creates a suction that pulls the walls together and inhibits sliding.”
For decades, studies of rocks unearthed from fault zones have revealed telltale cracks, mineral-filled veins and other signs that pressure can fluctuate wildly during and between big quakes, leading geologists to theorize that water and other fluids play an important role in triggering earthquakes and influencing when the biggest temblors strike. “The rocks themselves are telling us this is an important process,” Dunham said.
More recently, scientists have documented that fluid injection related to energy operations can lead to earthquake swarms. Seismologists have linked oil and gas wastewater disposal wells, for example, to a dramatic increase in earthquakes in parts of Oklahoma starting around 2009. And they’ve found that earthquake swarms migrate along faults faster or slower in different environments, whether it’s underneath a volcano, around a geothermal operation or within oil and gas reservoirs, possibly because of wide variation in fluid production rates, Dunham explained. But modeling had yet to untangle the web of physical mechanisms behind the observed patterns.
Dunham and Zhu’s work builds on a concept of faults as valves, which geologists first put forth in the 1990s. “The idea is that fluids ascend along faults intermittently, even if those fluids are being released or injected at a steady, constant rate,” Dunham explained. In the decades to thousands of years between large earthquakes, mineral deposition and other chemical processes seal the fault zone.
With the fault valve closed, fluid accumulates and pressure builds, weakening the fault and forcing it to slip. Sometimes this movement is too slight to generate ground shaking, but it’s enough to fracture the rock and open the valve, allowing fluids to resume their ascent.
The new modeling shows for the first time that as these pulses travel upward along the fault, they can create earthquake swarms. “The concept of a fault valve, and intermittent release of fluids, is an old idea,” Dunham said. “But the occurrence of earthquake swarms in our simulations of fault valving was completely unexpected.”
Predictions, and their limits
The model makes quantitative predictions about how quickly a pulse of high-pressure fluids migrates along the fault, opens up pores, causes the fault to slip and triggers certain phenomena: changes in the locking depth, in some cases, and imperceptibly slow fault movements or clusters of small earthquakes in others. Those predictions can then be tested against the actual seismicity along a fault — in other words, when and where small or slow-motion earthquakes end up occurring.
For instance, one set of simulations, in which the fault was set to seal up and halt fluid migration within three or four months, predicted a little more than an inch of slip along the fault right around the locking depth over the course of a year, with the cycle repeating every few years. This particular simulation closely matches patterns of so-called slow-slip events observed in New Zealand and Japan — a sign that the underlying processes and mathematical relationships built into the algorithm are on target. Meanwhile, simulations with sealing dragged out over years caused the locking depth to rise as pressure pulses climbed upward.
Changes in the locking depth can be estimated from GPS measurements of the deformation of Earth’s surface. Yet the technology is not an earthquake predictor, Dunham said. That would require more complete knowledge of the processes that influence fault slip, as well as information about the particular fault’s geometry, stress, rock composition and fluid pressure, he explained, “at a level of detail that is simply impossible, given that most of the action is happening many miles underground.”
Rather, the model offers a way to understand processes: how changes in fluid pressure cause faults to slip; how sliding and slip of a fault breaks up the rock and makes it more permeable; and how that increased porosity allows fluids to flow more easily.
In the future, this understanding could help to inform assessments of risk related to injecting fluids into the Earth. According to Dunham, “The lessons that we learn about how fluid flow couples with frictional sliding are applicable to naturally occurring earthquakes as well as induced earthquakes that are happening in oil and gas reservoirs.”
This research was supported by the National Science Foundation and the Southern California Earthquake Center.
Reference:
Weiqiang Zhu, Kali L. Allison, Eric M. Dunham, Yuyun Yang. Fault valving and pore pressure evolution in simulations of earthquake sequences and aseismic slip. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-18598-z
Note: The above post is reprinted from materials provided by Stanford University. Original written by Josie Garthwaite.
Nanolite ‘snow’ surrounding an iron oxide microlite ‘Christmas tree’. Even these small 50 nm spheres are actually made up of even smaller nanolites aggregated into clumps. Christmas has come early this year for these researchers. Credit: Brooker/Griffiths/Heard/Cherns
In a new study of volcanic processes, Bristol scientists have demonstrated the role nanolites play in the creation of violent eruptions at otherwise ‘calm’ and predictable volcanoes.
The study, published in Science Advances, describes how nano-sized crystals (nanolites), 10,000 times smaller than the width of a human hair, can have a significant impact of the viscosity of erupting magma, resulting in previously unexplained and explosive eruptions.
“This discovery provides an eloquent explanation for violent eruptions at volcanos that are generally well behaved but occasionally present us with a deadly surprise, such as the 122 BC eruption of Mount Etna,” said Dr Danilo Di Genova from the University of Bristol’s School of Earth Sciences.
“Volcanoes with low silica magma compositions have very low viscosity, which usually allows the gas to gently escape. However, we’ve shown that nanolites can increase the viscosity for a limited time, which would trap gas in the sticky liquid, leading to a sudden switch in behaviour that was previously difficult to explain.”
Dr Richard Brooker also from Earth Sciences, said: “We demonstrated the surprising effect of nanolites on magma viscosity, and thereby volcanic eruptions, using cutting-edge nano-imaging and Raman spectroscopy to hunt for evidence of these almost invisible particles in ash erupted during very violent eruptions.”
“The next stage was to re-melt these rocks in the laboratory and recreate the correct cooling rate to produce nanolites in the molten magma. Using the scattering of extremely bright synchrotron source radiation (10 billion times brighter than the sun) we were able to document nanolite growth.”
“We then produced a nanolite-bearing basaltic foam (pumice) under laboratory conditions, also demonstrating how these nanolites can be produced by undercooling as volatiles are exsolved from magma, lowering the liquidus.”
Professor Heidy Mader added: “By conducting new experiments on analogue synthetic materials, at low shear rates relative to volcanic systems, we were able to demonstrate the possibility of extreme viscosities for nanolite-bearing magma, extending our understanding of the unusual (non-Newtonian) behaviour of nanofluids, which have remained enigmatic since the term was coined 25 years ago.”
The next stage for this research is to model this dangerous, unpredictable volcanic behaviour in actual volcanic situations. This is the focus of a Natural Environment Research Council (UK) and National Science Foundation (US) grant ‘Quantifying Disequilibrium Processes in Basaltic Volcanism’ awarded to Bristol and a consortium of colleagues in Manchester, Durham, Cambridge and Arizona State University.
Reference:
Danilo Di Genova, Richard A. Brooker, Heidy M. Mader, James W. E. Drewitt, Alessandro Longo, Joachim Deubener, Daniel R. Neuville, Sara Fanara, Olga Shebanova, Simone Anzellini, Fabio Arzilli, Emily C. Bamber, Louis Hennet, Giuseppe La Spina, Nobuyoshi Miyajima. In situ observation of nanolite growth in volcanic melt: A driving force for explosive eruptions. Science Advances, 2020; 6 (39): eabb0413 DOI: 10.1126/sciadv.abb0413
Life reconstruction of Euparkeria highlighting the body parts investigated in this study. Credit: Oliver Demuth
Scientists from the University of Bristol and the Royal Veterinary College (RVC) used three-dimensional computer modelling to investigate the hindlimb of Euparkeria capensis–a small reptile that lived in the Triassic Period 245 million years ago–and inferred that it had a “mosaic” of functions in locomotion.
The study, which was published today in Scientific Reports, was led by researcher Oliver Demuth, joined by Professors Emily Rayfield (Bristol) and John Hutchinson (RVC). Their new micro-computed tomography scans of multiple specimens revealed unprecedented information about the previously hidden shape of the hip bones and structure of the foot and ankle joint.
Euparkeria has been known from numerous fossil specimens since the early 1900s and was found to be a close relative of the last common ancestor of both crocodiles and birds. While birds and crocodiles show different locomotion strategies, two-legged birds with an upright (erect) posture, shared with two and four-legged dinosaurs, and crocodiles having a four-legged (quadrupedal) sprawling posture, their ancestor once shared a common mode of locomotion and Euparkeria can provide vital insight into how these differences came to be.
The authors’ new reconstruction of the hip structure showed that Euparkeria had a distinctive bony rim on the pelvis, called a supra-acetabular rim, covering the top of the hip joint. This feature was previously known only from later archosaurs on the line to crocodiles and often was used to infer a more erect posture for these animals; reversed in crocodiles as they became more amphibious. The hooded rim allowed the pelvis to cover the top of the thigh bone and support the body with the limbs in a columnar arrangement; hence this type of joint is called ‘pillar-erect’. Euparkeria is so far the earliest reptile with this structure preserved. Could it therefore have assumed a more erect, rather than more sprawling, posture as well?
To test how the hindlimb could or could not have moved in life, the team estimated how far the thigh bone could have rotated until it collided with the hip bones, and their models addressed how the ankle joint could have been posed, too. The computer simulations suggested that while the thigh bone could have been held in an erect posture, the foot could not have been placed steadily on the ground due to the way the foot rotates around the ankle joint, implying a more sprawling posture. However, the bony rim covering the hip joint restricted the movement of the thigh bone in a way that is unknown in any living animal capable of a more sprawling gait, hinting at a more upright posture.
The team’s simulations thus revealed seemingly contradictory patterns in the hip and ankle joint. While Euparkeria is so far the earliest reptile with this peculiar hip structure, an ankle joint allowing a more erect posture appeared later on in Triassic archosaurs. Dr. John Hutchinson, professor of evolutionary biomechanics at the RVC, said, “The mosaic of structures present in Euparkeria, then, can be seen as a central stepping-stone in the evolution of locomotion in archosaurs.”
First author Oliver Demuth, research technician at the RVC and former Masters student at the University of Bristol, said, “The hip structure of Euparkeria was extremely surprising, especially as it functionally contradicts the ankle joint. Previously it was thought that both were linked and evolved synchronously. However, we were able to demonstrate that these traits were in fact decoupled and evolved in a step-wise fashion.”
Dr. Emily Rayfield, professor of palaeobiology at the University of Bristol, said, “This approach is exciting because Using CT scan datasets and computer models of how the bones and joints fitted together has allowed us to test long-standing ideas of how these ancient animals moved and how the limbs of the earliest ancestors of birds, crocodiles and dinosaurs may have evolved”
Reference:
Oliver E. Demuth et al. 3D hindlimb joint mobility of the stem-archosaur Euparkeria capensis with implications for postural evolution within Archosauria, Scientific Reports (2020). DOI: 10.1038/s41598-020-70175-y
Life reconstruction of the fossil bird Confuciusornis, one of the first beaked birds. Confuciusornis was roughly the size of a crow. It is known from hundreds of beautifully-preserved fossils, found in Early Cretaceous rocks from northeastern China. Credit: Gabriel Ugueto
Confuciusornis was a crow-like fossil bird that lived in the Cretaceous ~120 million years ago. It was one of the first birds to evolve a beak. Early beak evolution remains understudied. Using an imaging technique called Laser-Stimulated Fluorescence, researchers at the University of Hong Kong (HKU) address this by revealing just how different the beak and jaw of Confuciusornis were compared to birds we see today.
Laser-Stimulated Fluorescence (LSF) is an imaging technique co-developed at HKU that involves shining a laser onto a target. It is well-known in palaeontology for making fossil bones and the soft tissues preserved alongside them glow-in-the-dark. LSF has revealed fine skin details and other previously-invisible soft tissue in a wide range of fossils, especially those of early birds and other feathered dinosaurs.
HKU PhD student Case Vincent Miller and his supervisor Research Assistant Professor Dr. Michael Pittman (Vertebrate Palaeontology Laboratory, Division of Earth and Planetary Science & Department of Earth Sciences) led this study with Thomas G. Kaye of the Foundation for Scientific Advancement (Arizona, USA) and colleagues at the Shandong Tianyu Museum of Nature (Pingyi, China). Under LSF, which was co-developed by Dr. Pittman and Mr. Kaye, the team revealed the fingernail-like ‘soft beak’ of Confuciusornis, a feature that covers the beak of every bird and is called the rhamphotheca. The example the team found in Confuciusornis was preserved detached from the bony part of the beak. “Fossilised rhamphothecae have been reported in fossil birds before,” said Dr. Pittman, “but no one has really asked what they tell us about the earliest beaked birds.”
The international research team reconstructed what the beak looked like in life, and used this to consolidate knowledge of the beak of Confucusornis across all known specimens. In highlighting that the rhamphotheca was easily-detachable and by performing the first test of jaw strength in a dinosaur-era bird, the team suggested that this early beaked bird was suited to eating soft foods. Finally, the team highlight differences in how the beak is assembled to show that despite looking like living birds, the early beaks of Confuciusornis and its close relatives are fundamentally different structures to those seen in modern birds.
Regarding future plans, Mr. Miller said, “Our research has raised a lot of interesting questions going forward. We know so little about fossil rhamphothecae and plan on using LSF to study even more fossils to find more of these hidden gems. I am particularly interested in seeing whether beak attachment strength in living birds has any correlation with the overall strength of their jaw. This might help us to better understand fossil birds. This study is only the first glimpse into this interesting and new line of study into early beaks, so I am very excited.”
Reference:
Case Vincent Miller, Michael Pittman, Thomas G. Kaye, Xiaoli Wang, Jen A. Bright, Xiaoting Zheng. Disassociated rhamphotheca of fossil bird Confuciusornis informs early beak reconstruction, stress regime, and developmental patterns. Communications Biology, 2020; 3 (1) DOI: 10.1038/s42003-020-01252-1
A bundle of giant sperm of the present-day ostracod crustacean Cyclocypris serena. Photo credit: R. Matzke-Karasz.
An international collaboration between researchers at Queen Mary University of London and the Chinese Academy of Science in Nanjing has led to the discovery of world’s oldest animal sperm inside a tiny crustacean trapped in amber around 100 million years ago in Myanmar.
A rare find
The research team, led by Dr He Wang of the Chinese Academy of Science in Nanjing, found the sperm in a new species of crustacean they named Myanmarcypris hui. They predict that the animals had sex just before their entrapment in the piece of amber (tree resin), which formed in the Cretaceous period.
Fossilised sperms are exceptionally rare; previously the oldest known examples were only 17 million years old. The study, published in Royal Society Proceedings B, has implications for understanding the evolutionary history of an unusual mode of sexual reproduction involving “giant sperm”.
The crustacean is an ostracod, a kind of invertebrate animal that has existed for 500 million years and is represented today by thousands of species living in oceans, lakes and rivers. Their fossil shells are common and abundant but finding specimens preserved in ancient amber with their appendages and internal organs intact provides a rare and exciting opportunity to learn more about their evolution.
Professor Dave Horne, of Queen Mary University of London’s School of Geography and a co-author of this study, explains: “Analyses of fossil ostracod shells are hugely informative about past environments and climates, as well as shedding light on evolutionary puzzles, but exceptional occurrences of fossilised soft parts like this lead to remarkable advances in our understanding”. During the Cretaceous period in what is now Myanmar the ostracods were probably living in a coastal lagoon fringed by trees where they became trapped in a blob of tree resin.
Furthering understandings of ecology
The Kachin amber of Myanmar has previously yielded outstanding finds including frogs, snakes and a feathered dinosaur tail. “Hundreds of new species have been described in the past five years, and many of them have made evolutionary biologists re-consider long-standing hypotheses on how certain lineages developed and how ecological relationships evolved” reports co-author Bo Wang, also of the Chinese Academy of Science in Nanjing.
Ostracods may be extremely small (typically less than one millimetre long) but in one sense they are giants. Males of most animals (including humans) typically produce tens of millions of really small sperm in very large quantities, but there are exceptions. Some tiny fruit flies (insects) and ostracods (crustaceans) are famous for investing in quality rather than quantity: relatively small numbers of “giant” sperm longer than the animal itself, a by-product of evolutionary competition for reproductive success. The new find from Myanmar had already evolved giant sperm, and the specially-adapted organs to transfer them from male to female, 100 million years ago.
Using X-ray microscopy the team made computer-aided 3D reconstructions of the ostracods embedded in the amber, revealing incredible detail. “The results were amazing – not only did we find their tiny appendages to be preserved inside their shells, we could also see their reproductive organs” reports Dr He Wang. “But when we identified the sperms inside the female, and knowing the age of the amber, it was one of those special Eureka-moments in a researcher’s life”.
Traits of evolution
Wang’s team found adult males and females but it was a female specimen that contained the sperm, indicating that it must have had sex shortly before becoming trapped in the amber. The reconstructions also revealed the distinctive muscular sperm pumps and penises (two of each) that male ostracods use to inseminate the females, who store them in bag-like receptacles until eggs are ready to be fertilised.
Such extensive adaptation raises the question of whether reproduction with giant sperms can be an evolutionarily-stable character. “To show that using giant sperms in reproduction is not an extinction-doomed extravagance of evolution, but a serious long-term advantage for the survival of a species, we need to know when they first appeared” says co-author Dr Renate Matzke-Karasz of Ludwig-Maximilians-University in Munich.
This new evidence of the persistence of reproduction with giant sperm for a hundred million years shows it to be a highly successful reproductive strategy that evolved only once in this group – quite impressive for a trait that demands such a substantial investment from both males and females, especially when you consider that many ostracods can reproduce asexually, without needing males at all. “Sexual reproduction with giant sperm must be very advantageous” says Matzke-Karasz.
Dr He Wang of the Chinese Academy of Science in Nanjing, previously spent a year of his PhD studies working with Professor Dave Horne in the School of Geography at Queen Mary University of London, and the pair have already published several joint studies of fossil ostracods.
Reference:
He Wang, Renate Matzke-Karasz, David J. Horne, Xiangdong Zhao, Meizhen Cao, Haichun Zhang, Bo Wang. Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods. Proceedings of the Royal Society B: Biological Sciences, 2020; 287 (1935): 20201661 DOI: 10.1098/rspb.2020.1661
Larger: A back-scattered electron image of a microscopic crystal of priscillagrewite-(Y) enclosed in fluorapatite. Inset: An optical image of the same crystal. Credit: American Mineralogist / Irina Galuskina et al.
The greatest Christmas present Priscilla Grew received last year was an email.
Priscilla and husband Ed were vacationing in Hawaii, escaping the respective winter climes of Nebraska and Maine, when it arrived in late December.
It came from another married couple, Irina Galuskina and Evgeny Galuskin, whom Priscilla and Ed first met in 2010 at a meeting in Budapest. And it contained a surprise: “We found a new garnet and would like to name it ‘prisgrewite.’ We hope that Priscilla will agree!”
“I was just totally thrilled and overwhelmed,” said Grew, professor emeritus of Earth and atmospheric sciences and director emeritus of the University of Nebraska State Museum. “There are only about 5,600 (known) minerals, and only about a hundred are named for women.”
Though the Galuskins call her by the Russian nickname “Pris,” the International Mineralogical Association preferred her full name for the recently announced mineral: priscillagrewite-(Y). The mineral is a member of the so-called garnet supergroup, making it the equivalent of a semi-distant relative to more conventional garnet species. What sets it apart from all but one of its garnet brethren—it contains the element yttrium—is also what puts the “Y” in its name.
The Galuskins have honored Grew with their discovery partly as a tribute to one of her own, which she notched in 1966 while conducting doctoral research at the University of California, Berkeley. Alone in a lab at around 2 in the morning, Grew was analyzing a California garnet with a then-state-of-the-art instrument known as an electron microprobe, which fires a beam of electrons at a sample and records the resulting X-rays to identify the elements in it.
“This little picture, like a Polaroid, came out,” Grew said of the black-and-white output. “And there was this geometric pattern of light and dark zones.”
That angular pattern resembled the concentric rings of a tree trunk, she said, with the light zones representing higher levels of the element manganese. The phenomenon, what geologists call oscillatory zoning, indicated that the amount of nearby manganese had oscillated—high, then low, then high again, and so on—as the garnet had grown and crystallized over time.
Grew realized she was the first to observe those manganese zones in a garnet. Then and there, in the middle of the night and Berkeley’s empty Earth sciences building, she celebrated.
“I actually went out in the hall, and I ran up and down the hall, sort of skipping, shouting, ‘Yay!’ It’s the only time in my life that I’ve had a real first-ever-seen-by-human moment.”
It was a major geological achievement in a career that would come to be defined by them. But even before that moment, Grew’s colleagues at Berkeley had taken to calling her the “garnet lady.” Grew said the title has since passed to Galuskina, who, with the co-discovery of priscillagrewite-(Y), has now unearthed and named eight approved garnet species.
The Galuskins named two other minerals, edgrewite and hydroxyledgrewite, for Priscilla’s husband in 2011. Ed “lucked out,” Priscilla said, because the former mineral was already named by the time the researchers discovered the latter, whose similarity in atomic structure and composition ensured it would receive the same root name.
“Since he already had the one, they didn’t have a choice,” she joked. “People are kind of jealous, because you’re only supposed to get one mineral name per person.”
Official samples of Ed’s minerals reside at the Fersman Mineralogical Museum of the Russian Academy of Sciences in Moscow, where a specimen of priscillagrewite-(Y) will soon join them.
The Galuskins and colleague Yevgeny Vapnik collected the so-called Daba Marble rock containing priscillagrewite-(Y) in 2015, at a quarry near the Tulūl al Ḩammām region of Jordan. The quarry resides just east of the historic Hejaz Railway, which was once attacked by Arab raiders led by T.E. Lawrence and later immortalized in the film “Lawrence of Arabia.”
After finishing lab work that revealed the existence of priscillagrewite-(Y), the Galuskins proceeded to search the scientific literature—and found that the same garnet had been independently synthesized, also in 2015, by researchers at China’s Lanzhou University.
“I am so thrilled that my new mineral was discovered in Jordan,” Grew said. “My father was a minister, and as a child, we used to look together at the colored maps in the back of the Bible. I have always been fascinated by the Middle East.”
The mineral, specifically its name, has another connection to history. In September 1620—400 years ago to the month—the Pilgrim ancestor for whom Grew was named, Priscilla Mullins Alden, was aboard the Mayflower as it departed England for America.
But its ties to the past potentially stretch back even further. Another of Galuskina’s recently discovered garnets turned up in a meteorite and is thought to have crystallized from the solar nebula—the same cloud of gas and dust that would eventually form the planets of the solar system. Given its similarity to that “solar garnet,” there’s a reasonable chance priscillagrewite-(Y) is one, too.
And that’s not all. Priscillagrewite-(Y) grows in microscopic crystals about 10% the diameter of a human hair and is found inside another mineral, green fluorapatite, that itself is housed in Daba Marble. Archeologists have excavated beads and pendants made from green and red Daba Marble at sites that date back to before 6,000 B.C.
“It’s the most extraordinary-looking stone. In the Middle East, these Daba Marble ornaments are some of the oldest known stone ornaments that were ever made in this area,” Grew said. “I was so lucky to get a mineral like this, because I could have gotten one that just had no lore.”
Ostracod crustaceans were entrapped in this tiny piece of Cretaceous amber found in Myanmar.
An international team of paleontologists has discovered giant sperm cells in a 100-million year-old female ostracod preserved in a sample of amber. Clearly, the tiny crustacean had mated shortly before being entombed in a drop of tree resin.
In another fascinating snapshot from deep time, an international team of paleontologists has reported the discovery of specimens of a minuscule crustacean that dates back to the Cretaceous (about 100 million years ago), conserved in samples of amber from Myanmar. The most spectacular find is a single female, which turns out on closer examination to contain giant sperm cells in its reproductive tract. In fact, this is the oldest fossil in which sperm cells have been conclusively identified. Moreover, the specimen represents a previously unknown species of crustacean, which has been named Myanmarcypris hui. M. hui was an ostracod, as clearly indicated by the paired calcareous valves that form the carapace, whose form recalls that of a mussel shell. Ostracods have been around for 500 million years, and thousands of modern species have been described. They are found in the oceans and in freshwater lakes and rivers. Fossilized shells of these crustaceans are by no means rare, but the specimens preserved in Burmese amber reveal details of their internal organs, including those involved in reproduction. “The finds gave us an extremely rare opportunity to learn more about the evolution of these organs,” says Ludwig-Maximilians-Universitaet (LMU) in Munich geobiologist Renate Matzke-Karasz, who played a major role in the morphological analysis of the fossils.
During the Cretaceous period, ostracods must have lived in the coastal and inland waters of what is now Myanmar, which were fringed by forests dominated by trees that produced huge quantities of resin. The newly described specimens are among the many organisms that were trapped in the oozing blobs of the gooey substance. In recent years, the amber found in the province of Kachin has yielded a spectacular trove of fossils, including frogs and snakes, as well as part of a putative dinosaur (according to new evidence, that specimen may actually represent an unusual lizard). Over the past 5 years, hundreds of previously unknown species have been described based on these inclusions. Indeed, many of them have forced evolutionary biologists to reconsider conventional hypotheses concerning phylogenetic and ecological relationships.
The new ostracod specimens were analyzed with the aid of computer-assisted 3D X-ray reconstructions. The images revealed astonishing details of the anatomy of these animals, ranging from their tiny limbs to their reproductive organs. — And in one female specimen, Matzke-Karasz and her colleagues discovered ripe sperm. The cells were discovered in the paired sperm receptacles in which they were stored after copulation, ready for release when the female’s eggs matured. “This female must have mated shortly before being encased in the resin,” says He Wang of the Chinese Academy of Sciences in Nanjing. The X-ray images also revealed the sperm pumps and the pair of penises that male ostracods insert into the twin gonopores of the females.
The finds in Burmese amber provide unprecedented insights into an unexpectedly ancient and advanced instance of evolutionary specialization. “The complexity of the reproductive system in these specimens raises the question of whether the investment in giant sperm cells might represent an evolutionarily stable strategy, says Matzke-Karasz. The males of most animal species (including humans) produce very large numbers of very small sperm. Comparatively few animals, including some fruit flies — and of course, ostracods — have opted for a different approach. They make a relatively small numbers of oversized sperm, whose motile tails are several times longer than the animal itself.
“In order to prove that the use of giant sperm is not an extravagant whim on the part of evolution, but a viable strategy that can confer an enduring advantage that enables species to survive for long periods of time, we must establish when this mode of reproduction first appeared,” says Matzke-Karasz. Examples of fossilized sperm cells are extremely rare. The oldest known ostracod sperm (prior to the new discovery) are 17 million years old, and the previous record age, 50 Myr, was held by a species of worm. The new evidence extends that age by a factor of at least two. The fact that animals had already developed giant sperm 100 million years ago implies that this reproductive strategy can indeed be successful in the (very) long term, Matzke-Karasz points out. “That’s a pretty impressive record for a trait that requires a considerable investment from both the males and females of the species. From an evolutionary point of view, sexual reproduction with the aid of giant sperm must therefore be a thoroughly profitable strategy.”
Reference:
He Wang, Renate Matzke-Karasz, David J. Horne, Xiangdong Zhao, Meizhen Cao, Haichun Zhang, Bo Wang. Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods. Proceedings of the Royal Society B: Biological Sciences, 2020; 287 (1935): 20201661 DOI: 10.1098/rspb.2020.1661
This image of Saturn’s icy, geologically active moon Enceladus was acquired by NASA’s Cassini spacecraft during its October 2015 flyby. Enceladus hides a global ocean of liquid salty water beneath its crust and might also have hydrothermal vents not unlike the hydrothermal vents that dot the ocean floor here on Earth. NASA/JPL-Caltech/Space Science Institute
New research led by the American Museum of Natural History and funded by NASA identifies a process that might have been key in producing the first organic molecules on Earth about 4 billion years ago, before the origin of life. The process, which is similar to what might have occurred in some ancient underwater hydrothermal vents, may also have relevance to the search for life elsewhere in the universe. Details of the study are published this week in the journal Proceedings of the National Academy of Sciences.
All life on Earth is built of organic molecules — compounds made of carbon atoms bound to atoms of other elements such as hydrogen, nitrogen and oxygen. In modern life, most of these organic molecules originate from the reduction of carbon dioxide (CO2) through several “carbon-fixation” pathways (such as photosynthesis in plants). But most of these pathways either require energy from the cell in order to work, or were thought to have evolved relatively late. So how did the first organic molecules arise, before the origin of life?
To tackle this question, Museum Gerstner Scholar Victor Sojo and Reuben Hudson from the College of the Atlantic in Maine devised a novel setup based on microfluidic reactors, tiny self-contained laboratories that allow scientists to study the behavior of fluids — and in this case, gases as well — on the microscale. Previous versions of the reactor attempted to mix bubbles of hydrogen gas and CO2 in liquid but no reduction occurred, possibly because the highly volatile hydrogen gas escaped before it had a chance to react. The solution came in discussions between Sojo and Hudson, who shared a lab bench at the RIKEN Center for Sustainable Resource Science in Saitama, Japan. The final reactor was built in Hudson’s laboratory in Maine.
“Instead of bubbling the gases within the fluids before the reaction, the main innovation of the new reactor is that the fluids are driven by the gases themselves, so there is very little chance for them to escape,” Hudson said.
The researchers used their design to combine hydrogen with CO2 to produce an organic molecule called formic acid (HCOOH). This synthetic process resembles the only known CO2-fixation pathway that does not require a supply of energy overall, called the Wood-Ljungdahl acetyl-CoA pathway. In turn, this process resembles reactions that might have taken place in ancient oceanic hydrothermal vents.
“The consequences extend far beyond our own biosphere,” Sojo said. “Similar hydrothermal systems might exist today elsewhere in the solar system, most noticeably in Enceladus and Europa — moons of Saturn and Jupiter, respectively — and so predictably in other water-rocky worlds throughout the universe.”
“Understanding how carbon dioxide can be reduced under mild geological conditions is important for evaluating the possibility of an origin of life on other worlds, which feeds into understanding how common or rare life may be in the universe,” added Laurie Barge from NASA’s Jet Propulsion Laboratory, an author on the study.
The researchers turned CO2 into organic molecules using relatively mild conditions, which means the findings may also have relevance for environmental chemistry. In the face of the ongoing climate crisis, there is an ongoing search for new methods of CO2 reduction.
“The results of this paper touch on multiple themes: from understanding the origins of metabolism, to the geochemistry that underpins the hydrogen and carbon cycles on Earth, and also to green chemistry applications, where the bio-geo-inspired work can help promote chemical reactions under mild conditions,” added Shawn E. McGlynn, also an author of the study, based at the Tokyo Institute of Technology.
Other authors on this study include Ruvan de Graaf and Mari Strandoo Rodin from the College of the Atlantic, Aya Ohno from the RIKEN Center for Sustainable Resource Science in Japan, Nick Lane from University College London, Yoichi M.A. Yamada from RIKEN, Ryuhei Nakamura from RIKEN and Tokyo Institute of Technology, and Dieter Braun from Ludwig-Maximilians University in Munich.
This work was supported in part by NASA’s Maine Space Grant Consortium (SG-19-14 and SG-20-19), the U.S. National Science Foundation (1415189 and 1724300), the Japan Society for the Promotion of Science (FY2016-PE-16047 and FY2016-PE-16721), the National Institutes of Health’s National Institute of General Medical Sciences (P20GM103423), the European Molecular Biology Organization (ALTF- 725 1455-2015), the Institute for Advanced Study in Berlin, and the Gerstner Family Foundation.
Reference:
Reuben Hudson, Ruvan de Graaf, Mari Strandoo Rodin, Aya Ohno, Nick Lane, Shawn E. McGlynn, Yoichi M. A. Yamada, Ryuhei Nakamura, Laura M. Barge, Dieter Braun, Victor Sojo. CO2 reduction driven by a pH gradient. Proceedings of the National Academy of Sciences, 2020; 202002659 DOI: 10.1073/pnas.2002659117
Central Alps of Switzerland have been lifted to today’s height. Credit: ETH Zurich The Central Alps – in the middle of the picture the Oberalpstock – were not piled up in a bulldozer like manner but had been lifted to their present height. Credit: Peter Rüegg
For a long time, geoscientists have assumed that the Alps were formed when the Adriatic plate from the south collided with the Eurasian plate in the north. According to the textbooks, the Adriatic plate behaved like a bulldozer, thrusting rock material up in front of it into piles that formed the mountains. Supposedly, their weight subsequently pushed the underlying continental plate downwards, resulting in the formation of a sedimentary basin in the north adjacent to the mountains — the Swiss Molasse Plateau. Over time, while the mountains grew higher the basin floor sank deeper and deeper with the rest of the plate.
A few years ago, however, new geophysical and geological data led ETH geophysicist Edi Kissling and Fritz Schlunegger, a sediment specialist from the University of Bern, to express doubts about this theory. In light of the new information, the researchers postulated an alternative mechanism for the formation of the Alps.
Altitude of the Alps has barely changed
Kissling and Schlunegger pointed out that the topography and altitude of the Alps have barely changed over the past 30 million years, and yet the trench at the site of the Swiss Plateau has continued to sink and the basin extended further north. This leads the researchers to believe that the formation of the Central Alps and the sinking of the trench are not connected as previously assumed.
They argue that if the Alps and the trench indeed had formed from the impact of two plates pressing together, there would be clear indications that the Alps were steadily growing. That’s because, based on the earlier understanding of how the Alps formed, the collision of the plates, the formation of the trench and the height of the mountain range are all linked.
Furthermore, seismicity observed during the past 40 years within the Swiss Alps and their northern foreland clearly documents extension across the mountain ranges rather than the compression expected for the bulldozing Adria model.
The behaviour of the Eurasian plate provides a possible new explanation. Since about 60 Ma ago, the former oceanic part of the Eurasian plate sinks beneath the continental Adriatic microplate in the south. By about 30 Ma ago, this process of subduction is so far advanced that all oceanic lithosphere has been consumed and the continental part of the Eurasian plate enters the subduction zone.
This denotes the begin of the so-called continent-continent collision with the Adriatic microplate and the European upper, lighter crust separates from the heavier, underlying lithospheric mantle. Because it weighs less, the Earth’s crust surges upwards, literally creating the Alps for the first time around 30 Ma ago. While this is happening, the lithospheric mantle sinks further into the Earth’s mantle, thus pulling the adjacent part of the plate downwards.
This theory is plausible because the Alps are mainly made up of gneiss and granite and their sedimentary cover rocks like limestone. These crustal rocks are significantly lighter than the Earth’s mantle — into which the lower layer of the plate, the lithospheric mantle, plunges after the detachment of the two layers that form the continental plate. “In turn, this creates strong upward forces that lift the Alps out of the ground,” Kissling explains. “It was these upward forces that caused the Alps to form, not the bulldozer effect as a result of two continental plates colliding,” he says.
New model confirms lift hypothesis
To investigate the lift hypothesis, Luca Dal Zilio, former doctoral student in ETH geophysics professor Taras Gerya’s group, has now teamed up with Kissling and other ETH researchers to develop a new model. Dal Zilio simulated the subduction zone under the Alps: the plate tectonic processes, which took place over millions of years, and the associated earthquakes.
“The big challenge with this model was bridging the time scales. It takes into account lightning-fast shifts that manifest themselves in the form of earthquakes, as well as deformations of the crust and lithospheric mantle over thousands of years,” says Dal Zilio, lead author of the study recently published in the journal Geophysical Research Letters.
According to Kissling, the model is an excellent way to simulate the uplifting processes that he and his colleague are postulating. “Our model is dynamic, which gives it a huge advantage,” he says, explaining that previous models took a rather rigid or mechanical approach that did not take into account changes in plate behaviour. “All of our previous observations agree with this model,” he says.
The model is based on physical laws. For instance, the Eurasian plate would appear to subduct southwards. In contrast to the normal model of subduction, however, it doesn’t actually move in this direction because the position of the continent remains stable. This forces the subducting lithosphere to retreat northwards, causing the Eurasian plate to exert a suction effect on the relatively small Adriatic plate.
Kissling likens the action to a sinking ship. The resulting suction effect is very strong, he explains. Strong enough to draw in the smaller Adriatic microplate so that it collides with the crust of the Eurasian plate. “So, the mechanism that sets the plates in motion is not in fact a pushing effect but a pulling one,” he says, concluding that the driving force behind it is simply the pull of gravity on the subducting plate.
Rethinking seismicity
In addition, the model simulates the occurrence of earthquakes, or seismicity, in the Central Alps, the Swiss Plateau and below the Po Valley. “Our model is the first earthquake simulator for the Swiss Central Alps,” says Dal Zilio. The advantage of this earthquake simulator is that it covers a very long period of time, meaning that it can also simulate very strong earthquakes that occur extremely rarely.
“Current seismic models are based on statistics,” Dal Zilio says, “whereas our model uses geophysical laws and therefore also takes into account earthquakes that occur only once every few hundreds of years.” Current earthquake statistics tend to underestimate such earthquakes. The new simulations therefore improve the assessment of earthquake risk in Switzerland.
Reference:
Luca Dal Zilio, Edi Kissling, Taras Gerya, Ylona Dinther. Slab Rollback Orogeny Model: A Test of Concept. Geophysical Research Letters, 2020; 47 (18) DOI: 10.1029/2020GL089917
Note: The above post is reprinted from materials provided by ETH Zurich. Original written by Peter Rüegg.
Summary of major extinction events through time, highlighting the new, Carnian Pluvial Episode at 233 million years ago. Credit: D. Bonadonna/ MUSE, Trento
It’s not often a new mass extinction is identified; after all, such events were so devastating they really stand out in the fossil record. In a new paper, published today in Science Advances, an international team has identified a major extinction of life 233 million years ago that triggered the dinosaur takeover of the world. The crisis has been called the Carnian Pluvial Episode.
The team of 17 researchers, led by Jacopo Dal Corso of the China University of Geosciences at Wuhan and Mike Benton of the University of Bristol’s School of Earth Sciences, reviewed all the geological and palaeontological evidence and determined what had happened.
The cause was most likely massive volcanic eruptions in the Wrangellia Province of western Canada, where huge volumes of volcanic basalt was poured out and forms much of the western coast of North America.
“The eruptions peaked in the Carnian,” says Jacopo Dal Corso. “I was studying the geochemical signature of the eruptions a few years ago and identified some massive effects on the atmosphere worldwide. The eruptions were so huge, they pumped vast amounts of greenhouse gases like carbon dioxide, and there were spikes of global warming”.The warming was associated with increased rainfall, and this had been detected back in the 1980s by geologists Mike Simms and Alastair Ruffell as a humid episode lasting about 1 million years in all. The climate change caused major biodiversity loss in the ocean and on land, but just after the extinction event new groups took over, forming more modern-like ecosystems. The shifts in climate encouraged growth of plant life, and the expansion of modern conifer forests.
“The new floras probably provided slim pickings for the surviving herbivorous reptiles,” said Professor Mike Benton. “I had noted a floral switch and ecological catastrophe among the herbivores back in 1983 when I completed my Ph.D. We now know that dinosaurs originated some 20 million years before this event, but they remained quite rare and unimportant until the Carnian Pluvial Episode hit. It was the sudden arid conditions after the humid episode that gave dinosaurs their chance.”
It wasn’t just dinosaurs, but also many modern groups of plants and animals also appeared at this time, including some of the first turtles, crocodiles, lizards, and the first mammals.
The Carnian Pluvial Episode also had an impact on ocean life. It marks the start of modern-style coral reefs, as well as many of the modern groups of plankton, suggesting profound changes in the ocean chemistry and carbonate cycle.
“So far, palaeontologists had identified five “big” mass extinctions in the past 500 million years of the history of life,” says Jacopo Dal Corso. “Each of these had a profound effect on the evolution of the Earth and of life. We have identified another great extinction event, and it evidently had a major role in helping to reset life on land and in the oceans, marking the origins of modern ecosystems.”
