среда, 12 февраля 2020 г.

Tropical trees are living time capsules of human history

Tropical forest trees are the centerpiece of debates on conservation, climate change and carbon sequestration today. While their ecological importance has never been doubted, what has often been ignored is their ability to store cultural heritage. Using recent advances in scientific methods and a better understanding of the growth of these trees, researchers can now uncover, in detail, the growing conditions, including human management, that have occurred around these ancient giants over their centuries-long life span.

Tropical trees are living time capsules of human history
A Brazil nut tree in Jau National Park [Credit: Victor Caetano-Andrade]
In a new article published in Trends in Plant Science, an international team of scientists presents the combined use of dendrochronology, radiocarbon dating and isotopic and genetic analysis as a means of investigating the effects of human activities on forest disturbances and the growth dynamics of tropical tree species. The study presents the potential applicability of these methods for investigating prehistoric, historical and industrial periods in tropical forests around the world and suggests that they have the potential to detect time-transgressive anthropogenic threats, insights that can inform and guide conservation priorities in these rapidly disappearing environments.

Led by scientists from the Max Planck Institute for the Science of Human History and co-authored by leading scientists at the National Institute for Amazonian Research, The Max Planck Institute for Biogeochemisty and the Max Planck Institute for Developmental Biology, the study shows that tropical trees store records of changing human populations and their management practices, including activities that ultimately led to a 'domestication' of tropical landscapes. The study promotes a dialogue between various fields of research to ensure that tropical trees are acknowledged for their role in both cultural and natural ecosystems.

Tropical forests as centers of past human action

Tropical forests, long thought of as barriers to human migration, agricultural experimentation, and dense sedentary populations, have until recently been considered 'Green Deserts' in the context of past human activity. However, the last two decades have seen a wealth of research from various disciplines highlight extensive and diverse evidence of plant and animal domestication, including forest management, landscape alteration, and the deliberate translocation of wild taxa by ancient human societies—including the inhabitants of some of the largest pre-industrial cities on the face of the planet.

Tropical trees are living time capsules of human history
Settlement near useful plants on the banks of the Jau River, Amazonas, Brazil
[Credit: Victor Caetano-Andrade]
Western colonialism and the expansion of global capitalism resulted in new human impacts on these environments, with consumer decisions in Europe driving deforestation and tropical resource exploitation as they do to this day. Understanding how different societies, economic systems, and administrative organizations changed tropical forests is essential if we are to properly develop sustainable conservation policies.

Yet, high-resolution records of human impacts on tropical ecosystems are often difficult to come by. "Amazingly, this whole story has neglected some of the largest, most ancient witnesses tropical forests have to offer: their trees," says Victor Caetano Andrade, lead author of the study at the Max Planck Institute for the Science of Human History. "Archaeological excavation and archaeobotanical analyses has led to great strides in our recognition of past human lives in the tropics, but the trees themselves standing next to the trench have things to say as well," he continues.

Tree rings—a living stratigraphy

The study of tree rings has been frequently used in temperate environments to create a picture of how changing climate and human activities have altered forests. However, such work has been limited in the tropics, due to perceptions that a lack of seasonality meant no rings would be visible. As the authors note, however, it has now been demonstrated that more than 200 tropical tree species form annual rings. This opens up a whole new avenue for the exploration of changing tropical forest conditions in the past.

Tropical trees are living time capsules of human history
Researchers sampling a Brazil nut tree in Tapirape-Aquiri National Forest
[Credit: Victor Caetano-Andrade]
Counting tree rings can, alongside radiocarbon dating, produce robust, high-resolution chronologies or 'stratigraphies' of the growth of an individual tree. A change in the size of growth rings identified across a number of trees in the same forest can provide an indicator of abrupt changes in environmental conditions. In addition, these rings can be sampled chemically to investigate how climate conditions changed over time and how such changes correlate with tree growth. Where no strong correlation between climate and growth is visible, the door opens to other potential explanations, chief among them being human activity.

As Victor Caetano Andrade puts it, "There are some species of special importance for humans, for example as food trees or trees used for a particular purpose. In these cases humans would be likely to undertake forest management practices, such as clearing the understory, opening up the forest, and actively protecting individual trees." By contrast, other species may have been deliberately removed for use as construction material or to make way for settlement. Combining observations of tree growth with local historical and archaeological data allows scientists to look at the relationship between tree communities and past human societies and their economic practices.

Tree genes point to pre-Columbian forest management

DNA analysis of modern trees is commonly used by companies and foresters to select trees with economically desirable traits. However, modern genetic analysis, as well as analysis of preserved specimens, can reveal important insights into how populations of a given species have changed through space and time. Where relevant, this genetic analysis can be used to look at processes of domestication, including the selection for particular traits. The ability to associate patterns of genetic diversity for economically important trees with known archaeological records promises to reveal new insights into the settlement of tropical environments in the past.

Tropical trees are living time capsules of human history
This figure shows how humans promote or suppress trees, past and present
[Credit: Caeteno-Adrade et al. 2019]
The authors' review shows that in many cases in Central and South America, maximum genetic diversity of these species is found in areas with intense pre-Columbian human occupation. However, in addition to investigations of the distant past, the present study also shows that sampling of modern trees such as mahogany can document changes in genetic diversity before and after logging episodes. The authors propose that, given the advance of full genome sequencing, applying such methods to ancient modern trees in a given forest may make it possible to genetically reconstruct past human clearance and management events—particularly where detailed historical and archaeological information is also available.

While the majority of ecological study on the supposedly 'pristine' tropics has focused on how changes in forest structure and tree growth are linked to climate fluctuations and natural disturbances, the present research highlights centuries of human impact. As study co-author Dr. Patrick Roberts states, "The work evaluated here demonstrates two important findings: first, that human societies, from hunter-gatherers to urban dwellers, have played a significant role in tropical tree growth in the past; and second, that this role can be observed in trees that still stand today."

Furthermore, as Victor Caetano Andrade continues, "Multidisciplinary approaches to ancient trees will enable us to look at how forest management changed in the tropics from pre-colonial to post-colonial scenarios, and from pre-industrial to 21st century threats. The resolution available is remarkable and will allow us to get a handle on the legacies of past activities, and how changing practices have placed new pressures on these highly threatened environments". The authors conclude by arguing that it is essential that archaeologists and ecologists work together to preserve not just the natural benefits of tropical trees, but also the records of human cultural heritage and knowledge that span millennia stored within them.

Source: Max Planck Society [February 06, 2020]

* This article was originally published here

Distant Giant Planets Form Differently Than ‘Failed Stars’

This image of the low-mass brown dwarf gj 504 b was taken by bowler and his team using adaptive optics with the nirc2 camera at keck observatory in hawaii. the image has been processed to remove light from the host star (whose position is marked with an “x”). the companion is located at a separation of about 40 times the earth-sun distance and has an orbital period of about 240 years. by returning to this and other systems year after year, the team is able to slowly trace out part of the companion’s orbit to constrain its shape, which provides clues about its formation and history. Credit: Brendan Bowler (UT-Austin)/W. M. Keck Observatory

Maunakea, Hawaii – A team of astronomers led by Brendan Bowler of The University of Texas at Austin has probed the formation process of giant exoplanets and brown dwarfs, a class of objects that are more massive than giant planets, but not massive enough to ignite nuclear fusion in their cores to shine like true stars.

Using direct imaging with ground-based telescopes in Hawaii – W. M. Keck Observatory and Subaru Telescope on Maunakea – the team studied the orbits of these faint companions orbiting stars in 27 systems. These data, combined with modeling of the orbits, allowed them to determine that the brown dwarfs in these systems formed like stars, but the gas giants formed like planets.

The research is published in the current issue of The Astronomical Journal.

In the last two decades, technological leaps have allowed telescopes to separate the light from a parent star and a much-dimmer orbiting object. In 1995, this new capability produced the first direct images of a brown dwarf orbiting a star. The first direct image of planets orbiting another star followed in 2008.

“Over the past 20 years, we’ve been leaping down and down in mass,” Bowler said of the direct imaging capability, noting that the current limit is about 1 Jupiter mass. As the technology has improved, “One of the big questions that has emerged is ‘What’s the nature of the companions we’re finding?’”

By patiently watching giant planets and brown dwarfs orbit their host stars, Bowler and his team were able to constrain the orbit shapes even though only a small portion of the orbit has been monitored. The longer the time baseline, the smaller the range of possible orbits. These plots show nine of the 27 systems from their study. Credit: Brendan Bowler (UT-Austin) 

Brown dwarfs, as defined by astronomers, have masses between 13 and 75 Jupiter masses. They have characteristics in common with both planets and with stars, and Bowler and his team wanted to settle the question: Are gas giant planets on the outer fringes of planetary systems the tip of the planetary iceberg, or the low-mass end of brown dwarfs? Past research has shown that brown dwarfs orbiting stars likely formed like low-mass stars, but it’s been less clear what is the lowest mass companion this formation mechanism can produce.

“One way to get at this is to study the dynamics of the system — to look at the orbits,” Bowler said. Their orbits today hold the key to unlocking their evolution.

Using Keck Observatory’s adaptive optics (AO) system with the Near-Infrared Camera, second generation (NIRC2) instrument on the Keck II telescope, as well as the Subaru Telescope, Bowler’s team took images of giant planets and brown dwarfs as they orbit their parent stars.

It’s a long process. The gas giants and brown dwarfs they studied are so distant from their parent stars that one orbit may take hundreds of years. To determine even a small percentage of the orbit, “You take an image, you wait a year,” for the faint companion to travel a bit, Bowler said. Then “you take another image, you wait another year.”

This research relied on AO technology, which allows astronomers to correct for distortions caused by the Earth’s atmosphere. As AO instruments have continually improved over the past three decades, more brown dwarfs and giant planets have been directly imaged. But since most of these discoveries have been made over the past decade or two, the team only has images corresponding to a few percent of each object’s total orbit. They combined their new observations of 27 systems with all of the previous observations published by other astronomers or available in telescope archives.

At this point, computer modeling comes in. Coauthors on this paper have helped create an orbit-fitting code called “Orbitize!” which uses Kepler’s laws of planetary motion to identify which types of orbits are consistent with the measured positions, and which are not.

The code generates a set of possible orbits for each companion. The slight motion of each giant planet or brown dwarf forms a “cloud” of possible orbits. The smaller the cloud, the more astronomers are closing in on the companion’s true orbit. And more data points — that is, more direct images of each object as it orbits — will refine the shape of the orbit.

These two curves show the final distribution of orbit shapes for giant planets and brown dwarfs. The orbital eccentricity determines how elongated the ellipse is, with a value of 0.0 corresponding to a circular orbit and a high value near 1.0 being a flattened ellipse. Gas giant planets located at wide separations from their host stars have low eccentricities, but the brown dwarfs have a wide range of eccentricities similar to binary star systems. For reference, the giant planets in our solar system have eccentricities less than 0.1. Credit: Brendan Bowler (UT-Austin)

“Rather than wait decades or centuries for a planet to complete one orbit, we can make up for the shorter time baseline of our data with very accurate position measurements,” said team member Eric Nielsen of Stanford University. “A part of Orbitize! that we developed specifically to fit partial orbits, OFTI [Orbits For The Impatient], allowed us to find orbits even for the longest period companions.”

Finding the shape of the orbit is key: Objects that have more circular orbits probably formed like planets. That is, when a cloud of gas and dust collapsed to form a star, the distant companion (and any other planets) formed out of a flattened disk of gas and dust rotating around that star.

On the other hand, the ones that have more elongated orbits probably formed like stars. In this scenario, a clump of gas and dust was collapsing to form a star, but it fractured into two clumps. Each clump then collapsed, one forming a star, and the other a brown dwarf orbiting around that star. This is essentially a binary star system, albeit containing one real star and one “failed star.”

“Even though these companions are millions of years old, the memory of how they formed is still encoded in their present-day eccentricity,” Nielsen added. Eccentricity is a measure of how circular or elongated an object’s orbit is. The results of the team’s study of 27 distant companions was unambiguous.

“The punchline is, we found that when you divide these objects at this canonical boundary of more than about 15 Jupiter masses, the things that we’ve been calling planets do indeed have more circular orbits, as a population, compared to the rest,” Bowler said. “And the rest look like binary stars.”

The future of this work involves both continuing to monitor these 27 objects, as well as identifying new ones to widen the study. “The sample size is still modest, at the moment,” Bowler said. His team is using the Gaia satellite to look for additional candidates to follow up using direct imaging with even greater sensitivity at the forthcoming Giant Magellan Telescope (GMT) and other facilities. UT-Austin is a founding member of the GMT collaboration.

Bowler’s team’s results reinforce similar conclusions recently reached by the GPIES direct imaging survey with the Gemini Planet Imager, which found evidence for a different formation channel for brown dwarfs and giant planets based on their statistical properties.

This work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The Keck Observatory is managed by Caltech and the University of California.

About NIRC2

The Near-Infrared Camera, second generation (NIRC2) works in combination with the Keck II adaptive optics system to obtain very sharp images at near-infrared wavelengths, achieving spatial resolutions comparable to or better than those achieved by the Hubble Space Telescope at optical wavelengths. NIRC2 is probably best known for helping to provide definitive proof of a central massive black hole at the center of our galaxy. Astronomers also use NIRC2 to map surface features of solar system bodies, detect planets orbiting other stars, and study detailed morphology of distant galaxies.

About Adaptive Optics

W. M. Keck Observatory is a distinguished leader in the field of adaptive optics (AO), a breakthrough technology that removes the distortions caused by the turbulence in the Earth’s atmosphere. Keck Observatory pioneered the astronomical use of both natural guide star (NGS) and laser guide star adaptive optics (LGS AO) and current systems now deliver images three to four times sharper than the Hubble Space Telescope at near-infrared wavelengths. AO has imaged the four massive planets orbiting the star HR8799, measured the mass of the giant black hole at the center of our Milky Way Galaxy, discovered new supernovae in distant galaxies, and identified the specific stars that were their progenitors. Support for this technology was generously provided by the Bob and Renee Parsons Foundation, Change Happens Foundation, Gordon and Betty Moore Foundation, Mt. Cuba Astronomical Foundation, NASA, NSF, and W. M. Keck Foundation.

About W. M. Keck Observatory

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two, 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems.

Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

* This article was originally published here

Scientists resurrect mammoth's broken genes

Some 4,ooo years ago, a tiny population of woolly mammoths died out on Wrangel Island, a remote Arctic refuge off the coast of Siberia. They may have been the last of their kind anywhere on Earth.

Scientists resurrect mammoth's broken genes
Archaeological Recovered Mammoth Skeleton Bones Wrangel Island UNESCO
World Heritage Site Russia Arctic [Credit: Ngaire Hart, Flickr]
To learn about the plight of these giant creatures and the forces that contributed to their extinction, scientists have resurrected a Wrangel Island mammoth's mutated genes. The goal of the project was to study whether the genes functioned normally. They did not.

The research builds on evidence suggesting that in their final days, the animals suffered from a medley of genetic defects that may have hindered their development, reproduction and their ability to smell.

The problems may have stemmed from rapid population decline, which can lead to interbreeding among distant relatives and low genetic diversity -- trends that may damage a species' ability to purge or limit harmful genetic mutations.

"The key innovation of our paper is that we actually resurrect Wrangel Island mammoth genes to test whether their mutations actually were damaging (most mutations don't actually do anything)," says lead author Vincent Lynch, PhD, an evolutionary biologist at the University at Buffalo. "Beyond suggesting that the last mammoths were probably an unhealthy population, it's a cautionary tale for living species threatened with extinction: If their populations stay small, they too may accumulate deleterious mutations that can contribute to their extinction."

Lynch, an assistant professor of biological sciences in the UB College of Arts and Sciences, joined UB in 2019 and led the project while he was at the University of Chicago. The research was a collaboration between Lynch and scientists at the University of Chicago, Northwestern University, University of Virginia, University of Vienna and Penn State. The first authors were Erin Fry from the University of Chicago and Sun K. Kim from Northwestern University.

Scientists resurrect mammoth's broken genes
Credit: Rebecca Farnham/University at Buffalo
To conduct the study, Lynch's team first compared the DNA of a Wrangel Island mammoth to that of three Asian elephants and two more ancient mammoths that lived when mammoth populations were much larger.

The researchers identified a number of genetic mutations unique to the Wrangel Island mammoth. Then, they synthesized the altered genes, inserted that DNA into cells in petri dishes, and tested whether proteins expressed by the genes interacted normally with other genes or molecules.

The scientists did this for genes that are thought or known to be involved in a range of important functions, including neurological development, male fertility, insulin signaling and sense of smell.

In the case of detecting odors, for example, "We know how the genes responsible for our ability to detect scents work," Lynch says. "So we can resurrect the mammoth version, make cells in culture produce the mammoth gene, and then test whether the protein functions normally in cells. If it doesn't -- and it didn't -- we can infer that it probably means that Wrangel Island mammoths were unable to smell the flowers that they ate."

The research builds on prior work by other scientists, such as a 2017 paper in which a different research team identified potentially detrimental genetic mutations in the Wrangel Island mammoth, estimated to be a part of a population containing only a few hundred members of the species.

"The results are very complementary," Lynch says. "The 2017 study predicts that Wrangel Island mammoths were accumulating damaging mutations. We found something similar and tested those predictions by resurrecting mutated genes in the lab. The take-home message is that the last mammoths may have been pretty sick and unable to smell flowers, so that's just sad."

The study was published in the journal Genome Biology and Evolution.

Author: Charlotte Hsu | Source: University at Buffalo [February 07, 2020]

* This article was originally published here

Deformation of Zealandia, Earth's Hidden Continent, linked to forging of the Ring of Fire

Recent seafloor drilling has revealed that the "hidden continent " of Zealandia--a region of continental crust twice the size of India submerged beneath the southwest Pacific Ocean--experienced dramatic elevation changes between about 50 million and 35 million years ago. New findings from this expedition, published in Geology, propose this topographic upheaval may have been due to a widespread reactivation of ancient faults linked to formation of the western Pacific's infamous Ring of Fire.

Deformation of Zealandia, Earth's Hidden Continent, linked to forging of the Ring of Fire
Recent seafloor drilling has revealed that the 'hidden continent' of Zealandia -- a region of continental crust twice the
size of India submerged beneath the southwest Pacific Ocean -- experienced dramatic elevation changes between
about 50 million and 35 million years ago [Credit: International Ocean Discovery Program,
JOIDES Resolution Science Operator]
Since the 1970s the prevailing scientific wisdom has been that Zealandia's unusually low profile is due to the thinning of its crust as it separated from Gondwana, the ancient supercontinent that included Antarctica and Australia, around 85 million years ago. After these tectonic fireworks, says Rupert Sutherland, a geophysicist at New Zealand's Victoria University of Wellington and the paper's lead author, this model has Zealandia "doing nothing but gently cooling and subsiding."

But fossils in the drillcores collected in 2017 by International Ocean Discovery Program Expedition 371 indicate that during the early Cenozoic, portions of northern Zealandia rose 1-2 kilometers while other sections subsided about the same amount before the entire continent sank another kilometer deep underwater. The timing of these topographic transformations, say Sutherland and his co-authors, coincides with a global reorganization of tectonic plates evidenced by the bend in the Emperor-Hawaii seamount chain, the reorientation of numerous mid-ocean ridges, and the onset of subduction--and the related volcanism and seismicity--in a belt that still encircles much of the western Pacific.

Although subduction drives Earth's plate tectonic cycle, says Sutherland, scientists don't yet understand how it starts. The drilling expedition to Zealandia may offer new insights into this fundamental process. "One of the amazing things about our observations," says Sutherland, "is that they reveal the early signs of the Ring of Fire were almost simultaneous throughout the western Pacific." Because this timing predates the global tectonic plate reorganization, he says, scientists need to find an explanation for how subduction began across such a broad area in such a short time.

Sutherland and his co-authors propose a new mechanism: a 'subduction rupture event,' which they argue is similar to a massive, super-slow earthquake. The researchers believe the event resurrected ancient subduction faults that had lain dormant for many millions of years.

"We don't know where or why," says Sutherland, "but something happened that locally induced movement, and when the fault started to slip, like in an earthquake the motion rapidly spread sideways onto adjacent parts of the fault system and then around the western Pacific." But unlike an earthquake, Sutherland says, the subduction rupture event may have taken more than a million years to unfold. "Ultimately," he says, "Zealandia's sedimentary record should help us determine how and why this event happened and what the consequences were for animals, plants, and global climate."

The process has no modern analogue, according to Sutherland, and because the subduction rupture event is linked to a time of rapid, global plate tectonic change, other instances of such change in the geologic record may imply that comparable events have occurred in the past. "Geologists generally assume that understanding the present is the key to understanding the past," he says. "But at least in this instance, this may not hold."

Source: Geological Society of America [February 07, 2020]

* This article was originally published here

Barracks and Stables, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

Barracks and Stables, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

* This article was originally published here

Twist in the story of volcanism and mass extinctions

An emerging scientific consensus is that gases -- in particular carbon gases -- released by volcanic eruptions millions of years ago contributed to some of Earth's greatest mass extinctions. But new research at The City College of New York suggests that that's not the entire story.

Twist in the story of volcanism and mass extinctions
The Siberian Traps, the scene of ancient volcanic eruptions 252 million years ago that led to a massive extinction
of life on Earth. CCNY researchers Ellen Gales and Benjamin Black obtained samples for their study there
[Credit: B. Black and L.T. Elkins-Tanton]
"The key finding of our research is that carbon from massive, ancient volcanic eruptions does not line up well with the geochemical clues that tell us about how some of Earth's most profound mass extinctions occurred," said Benjamin Black, assistant professor in CCNY's Division of Science, whose expertise includes effects of volcanism on climate and mass extinctions.

The study by Black with his M.S. in geology student Ellen Gales, the lead author, is entitled "Carbonatites as a record of the carbon isotope composition of large igneous province outgassing." It appears in the current issue of the journal Earth and Planetary Science Letters, and is a product of Gales' thesis work.

The new data does not rule out volcanism as the culprit in driving past mass extinctions, the article points out. But it does conclude that there must have been something extra at work.

"Ellen's work is new in that scientists have previously guessed what the geochemical fingerprint of CO2 from these giant eruptions might be, but our findings are some of the first direct measurements of this fingerprint," said Black.

"Our finding challenges the idea that carbon from this kind of eruption might be special, and therefore capable of easily matching changes in the carbon cycle during mass extinctions. It also helps us understand how volcanic eruptions move carbon -- a key ingredient for life and climate -- around inside the Earth and between the solid Earth and the atmosphere," said Gales.

In addition, the CCNY research also offers insights into Earth's current climate. "Right now, people are releasing large quantities of CO2 into the atmosphere. In a way, we are heading into almost uncharted territory," noted Black. "This scale of CO2 release has only happened a few times in Earth's history, for example during rare, enormous volcanic eruptions like the ones we studied."

Consequently, Black pointed out, even though volcanic eruptions on the scale of these enormous volcanic provinces are not expected any time soon, understanding the environmental changes triggered by prodigious volcanic CO2 release in the deep past is important for understanding how Earth's climate could change in the coming centuries.

The researchers used samples collected from ancient volcanic eruptions including the 252-million-year-old Siberian Traps. They included data collected at Columbia University's Lamont-Doherty Earth Observatory. Lindy Elkins-Tanton at Arizona State University also contributed to the work, which received support from the National Science Foundation.

Source: The City University of New York [February 10, 2020]

* This article was originally published here

Commander’s House, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

Commander’s House, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

* This article was originally published here

Meet T-Rex's older cousin: The Reaper of Death

Scientists said Monday they had discovered a new species of dinosaur closely related to Tyrannosaurus rex that strode the plain of North America some 80 million years ago.

Meet T-Rex's older cousin: The Reaper of Death
Researchers said Thanatotheristes degrootorum was around eight metres long and hunted
around 80 million years ago [Credit: Julius Csotonyi/AFP]
Thanatotheristes degrootorum -- Greek for "Reaper of Death" -- is thought to be the oldest member of the T-Rex family yet discovered in northern North America, and would have grown to around eight metres (26 feet) in length.

"We chose a name that embodies what this tyrannosaur was as the only known large apex predator of its time in Canada, the reaper of death," Darla Zelenitsky, assistant professor of Dinosaur Palaeobiology at Canada's University of Calgary. "The nickname has come to be Thanatos," she told AFP.

Whereas T-Rex -- the most famous of all dinosaur species, immortalised in Steven Spielberg's 1993 epic Jurassic Park -- stalked its prey around 66 million years ago, Thanatos dates back at least 79 million years, the team said.

The specimen was discovered by Jared Voris, a PhD student at Calgary, and is the first new tyrannosaur species found for 50 years in Canada.

Meet T-Rex's older cousin: The Reaper of Death
The study found that Thanatos had a long, deep snout, similar to more primitive tyrannosaurs
that lived in the southern United States [Credit: Julius Csotonyi/AFP]

"There are very few species of tyrannosaurids, relatively speaking," said Zelenitsky, co-author of the study that appeared in the journal Cretaceous Research.

"Because of the nature of the food chain these large apex predators were rare compared to herbivorous or plant-eating dinosaurs."

The study found that Thanatos had a long, deep snout, similar to more primitive tyrannosaurs that lived in the southern United States.

The researchers suggested that the difference in tyrannosaur skull shapes between regions could have been down to differences in diet, and dependant on the prey available at the time.

Source: AFP [February 10, 2020]

* This article was originally published here

Gatehouse, Turret and Interval Towers, Chesters Roman Fort, Hadrian’s Wall, Northumberland,...

Gatehouse, Turret and Interval Towers, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

* This article was originally published here

Disease found in fossilized dinosaur tail afflicts humans to this day

The fossilized tail of a young dinosaur that lived on a prairie in southern Alberta, Canada, is home to the remains of a 60-million-year-old tumor.

Disease found in fossilized dinosaur tail afflicts humans to this day
Photograph of the larger hadrosaur vertebra in lateral view (left) and caudal view (right).
The space that contained the overgrowth opens to the caudal surface of the vertebra
[Credit: Assaf Ehrenreich, Sackler Faculty of Medicine, Tel Aviv University]
Researchers at Tel Aviv University, led by Dr. Hila May of the Department of Anatomy and Anthropology at TAU's Sackler Faculty of Medicine and Dan David Center for Human Evolution and Biohistory Research, have identified this benign tumor as part of the pathology of LCH (Langerhans cell histiocytosis), a rare and sometimes painful disease that still afflicts humans, particularly children under the age of 10.

A study on the TAU discovery was published in Scientific Reports. Prof. Bruce Rothschild of Indiana University, Prof. Frank Rühli of the University of Zurich and Mr. Darren Tanke of the Royal Museum of Paleontology also contributed to the research.

"Prof. Rothschild and Tanke spotted an unusual finding in the vertebrae of a tail of a young dinosaur of the grass-eating herbivore species, common in the world 66-80 million years ago," Dr. May explains. "There were large cavities in two of the vertebrae segments, which were unearthed at the Dinosaur Provincial Park in southern Alberta, Canada."

It was the specific shape of the cavities that attracted the attention of researchers.

"They were extremely similar to the cavities produced by tumors associated with the rare disease LCH that still exists today in humans," adds Dr. May. "Most of the LCH-related tumors, which can be very painful, suddenly appear in the bones of children aged 2-10 years. Thankfully, these tumors disappear without intervention in many cases."

The dinosaur tail vertebrae were sent for on-site advanced micro-CT scanning to the Shmunis Family Anthropology Institute at TAU's Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, which is located at the Steinhardt Museum of Natural History.

"The micro-CT produces very high-resolution imaging, up to a few microns," Dr. May says. "We scanned the dinosaur vertebrae and created a computerized 3D reconstruction of the tumor and the blood vessels that fed it. The micro and macro analyses confirmed that it was, in fact, LCH. This is the first time this disease has been identified in a dinosaur."

According to Dr. May, the surprising findings indicate that the disease is not unique to humans, and that it has survived for more than 60 million years.

"These kinds of studies, which are now possible thanks to innovative technology, make an important and interesting contribution to evolutionary medicine, a relatively new field of research that investigates the development and behavior of diseases over time," notes Prof. Israel Hershkovitz of TAU's Department of Anatomy and Anthropology and Dan David Center for Human Evolution and Biohistory Research. "We are trying to understand why certain diseases survive evolution with an eye to deciphering what causes them in order to develop new and effective ways of treating them."

Source: Tel Aviv University [February 11, 2020]

* This article was originally published here

Decorative Brooch, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

Decorative Brooch, Chesters Roman Fort, Hadrian’s Wall, Northumberland, 8.2.20.

* This article was originally published here

First Anglo-Saxon buildings found in Bath discovered during Abbey renovations

Experts from Wessex Archaeology have used scientific techniques to date the remains of two stone buildings, discovered during renovation work at Bath Abbey, to the 8th – 10th century.

First Anglo-Saxon buildings found in Bath discovered during Abbey renovations
Credit: Wessex Archaeology
They are likely part of the Anglo-Saxon monastery where King Edgar was crowned as first King of England in 973 AD. The two structures were discovered during excavations below street level, south of the current Abbey church, as part of Bath Abbey’s Footprint project.

The team from Wessex Archaeology uncovered the apsidal (semi-circular) structures below an area where the cloisters of the 12th-century cathedral would have once stood and overlying earlier Romano-British deposits. An internal plaster render on the southern-most apse contained fragments of charcoal from which two samples were sent for radiocarbon dating at Queen’s University, Belfast.

The dates came back as AD 780-970 and AD 670-770, much to the delight of Wessex Archaeology Senior Project Officer Cai Mason, who said: “When you find something unusual, you have to think ‘what is the most mundane explanation for what we’ve found?’, and most of the time that will be the explanation, but sometimes that doesn’t work, which makes you wonder ‘have we found something genuinely unusual?’

First Anglo-Saxon buildings found in Bath discovered during Abbey renovations
Credit: Wessex Archaeology
“In a post-Roman context, the most likely place to find this type of structure is at the east end of an ecclesiastical building, such as a church or chapel, and given the fact that the excavated structures are surrounded by late Saxon burials, this is the most likely explanation for their use. This, together with the late Saxon stonework and burials found at the Abbey, provides increasingly strong evidence that we have indeed found part of Bath’s lost Anglo-Saxon monastery.”

Wessex Archaeology Project Manager Bruce Eaton added: “Given that the potential date of these structures spans some 200 years there are several possible contexts for their construction.

“One possibility would be the reign of King Offa of Mercia, who acquired the monastery in AD 781 and is credited by William of Malmesbury for building the famous Church of St Peter, probably utilising the ready supply of worked stone from the near-by collapsing Roman baths complex. Extensive building work within this period is further attested to by Offa’s successor Ecgfrith having the infrastructure in place to hold court at the monastery in AD 796. This phase of energetic building activity does fit neatly with our earliest possible date for the plasterwork, but it is certainly not our only candidate.”

First Anglo-Saxon buildings found in Bath discovered during Abbey renovations
Credit: Wessex Archaeology
The Reverend Canon Guy Bridgewater at Bath Abbey, said: “This is a really exciting find. While we’ve always known there once was an Anglo-Saxon monastery on this site, no trace of the building remains above ground today, so it’s amazing that we now have an actual record of it and can get a real sense of it as it was.

“The excavations being carried out as part of our Footprint project are essential to make major improvements to the current Abbey church, and how we use it. A massive benefit has been working with Wessex Archaeology who are making important discoveries about the Abbey’s 1,000-year heritage all the time.”

The Anglo-Saxon structures are among a series of exciting discoveries made by Wessex Archaeology during their excavations at Bath Abbey.

In August 2018, the team uncovered a vibrantly coloured 14th century tiled floor in what would have been the nave of the medieval cathedral.

They have excavated a Mesolithic land surface below the Victorian plant room, Roman buildings which would have once stood in the heart of the town of Aquae Sulis, an Anglo-Saxon cemetery containing rare charcoal burials and the medieval cloister walk.

More recent finds have included the coffin-plate of controversial Georgian demographer Rev. Thomas Malthus and recovered painted fragments of the lost Jacobean plaster ceiling of the current Abbey church.

Source: Bath Echo [January 28, 2020]

* This article was originally published here

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* This article was originally published here


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