It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, January 27, 2024
Flame-retardant chemicals may increase risk of preterm birth, higher birth weight
Rutgers Health participated in a federal study that found certain organophosphate esters were linked to increased risk of early birth, especially in girls
Pregnant women exposed to specific classes of flame-retardant chemicals may face an increased risk of preterm birth, especially for baby girls, or higher birth weights, according to a Rutgers Health researcher.
Manufacturers commonly use organophosphate esters (OPEs) in products such as furniture, baby items, electronics, clothes and building materials to prevent fires and make plastics more flexible. People can come into contact with OPEs in various ways, including swallowing or breathing indoor dust or absorbing it through the skin.
In the past decade, OPEs increasingly have been used as flame retardants after polybrominated diphenyl ether (PBDE) flame retardants were phased out because of health risks. ECHO researchers wanted to learn how these now more widespread OPE chemicals might affect pregnancy outcomes such as preterm birth and birth weight.
“This is another regrettable case where new chemicals were introduced into consumer products without really understanding their health impacts,” said Barrett, a coauthor of the study. “Knowing now that OPE exposure is associated with adverse birth outcomes, we have to ask ourselves, ‘What are the downstream impacts on children’s health?’”
ECHO researchers found more than 85% of the study participants had three specific markers of OPE exposure in their bodies. Those three substances – diphenyl phosphate (DPHP), a combination of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP) and bis(1,3-dichloro-2-propyl) phosphate – were associated with shorter pregnancies and higher risks of preterm birth only among female infants. Among male infants, higher concentrations of DPHP were associated with longer pregnancies.
Babies born to mothers with detectable levels of three other OPE markers – bis(1-chloro-2-propyl) phosphate, bis(2-methylphenyl) phosphate, and dipropyl phosphate – tended to have higher birth weights compared with those whose mothers had no detectable levels of these substances. Babies with a higher birth weight might be more likely to have jaundice, breathing problems or congenital disorders.
Researchers measured a total of nine OPE markers in urine samples collected from 6,646 pregnant participants across 16 ECHO Cohort Study Sites, often during their third or second trimesters. The researchers assessed birth outcomes, including the length of pregnancy and birth weight, using medical records or parent reports.
“These substances tend to stay in the body for short periods, usually just hours to days,” said Deborah Bennett at the University of California, Davis, who led the study. “Conducting more thorough studies with various urine tests can help us figure out how they might be linked to birth outcomes.”
SRIKANTH SINGAMANENI AND BARANI RAMAN LED A TEAM THAT HARNESSED THE POWER OF SPECIALLY MADE NANOSTRUCTURES THAT CAN ABSORB LIGHT AND CREATE HEAT AND ACT AS CONTAINERS TO STORE AND RELEASE CHEMICALS ON DEMAND. THEY USED THESE NANOSTRUCTURED MATERIALS TO BOOST NEURAL RESPONSE IN THE LOCUST'S BRAIN TO SPECIFIC ODORS AND TO IMPROVE THEIR IDENTIFICATION.
Our sensory systems are highly adaptable. A person who cannot see after turning off a light in the night slowly achieves superior power to see even small objects. Women often attain a heightened sense of smell during pregnancy. How can the same sensory system that was underperforming can also exceed the expectation based on its prior performance?
Since nature has perfected its sensory systems over evolutionary time scales, an interdisciplinary team of researchers in the McKelvey School of Engineering at Washington University in St. Louis tapped into these capabilities to adapt the system on demand to perform at its peak performance. Their tools to achieve this goal: locusts and nanomaterials too small to see.
Srikanth Singamaneni and Barani Raman, both professors in the McKelvey School of Engineering, led a team that harnessed the power of specially made nanostructures that can absorb light and create heat, known as the photothermal effect, and act as containers to store and release chemicals on demand. They used these nanostructured materials to boost neural response in the locust's brain to specific odors and to improve their identification. Results of the research were published in Nature Nanotechnology Jan. 25, 2024.
Singamaneni, the Lilyan & E. Lisle Hughes Professor in the Department of Mechanical Engineering & Materials Science, and Raman, professor of biomedical engineering, have collaborated for years with Shantanu Chakrabartty, the Clifford W. Murphy Professor in the Preston M. Green Department of Electrical & Systems Engineering, to harness the superior sensing capabilities of the locust olfactory system. Recently they demonstrated the feasibility of using a bio-hybrid electronic nose for sensing explosive vapors.
“We let the biology do the harder job of converting information about vaporous chemicals into an electrical neural signal,” Raman said. “These signals are detected in the insect antennae and are transmitted to the brain. We can place electrodes in the brain, measure the locusts’ neural response to odors, and use them as fingerprints to distinguish between chemicals.”
The idea, though sound, has a potential roadblock.
“We are limited by the number of electrodes and where we can place them,” Singamaneni said. “Since we will get only a partial signal, we want to amplify this signal. This is where we turned to heat and neuromodulation to enhance the signal we get.”
In the new research, the team used two strategies to boost the locusts’ ability to detect odors. First, the team created a biocompatible and biodegradable polydopamine nanoparticle that converts light to heat through a process called photothermal effect.
"Heat affects diffusion,” Raman said. “Imagine adding cold milk to hot coffee. The idea is to use the heat generated by nanostructures to locally heat, for example, a nanoheater, and enhance the neural activity.”
Second, these nanostructured materials can be made to load chemicals for storage. However, they need to be encapsulated by a covering material. The team used a phase-change material called tetradecanol which is solid at room temperature and transitions to liquid upon heating. When heated, the same nanoheaters will ooze the chemicals stored within them in addition to generating heat.
Singamaneni and the team stored octopamine, a neuromodulator involved in various functions, and released it on demand. Usually, these neuromodulators are released based on the needs of the organism. However, using the nanostructured heaters, they were released on demand to enhance the neural signals.
“Our study presents a generic strategy to reversibly enhance neural signals at the brain site where we place the electrodes,” Raman said.
“The nano-enabled neuromodulation strategy we developed opens new opportunities to realize tailored cyborg chemical sensing approaches,” said Prashant Gupta, a graduate student in Singamaneni’s lab and first author of the paper. “This approach would change an existing passive approach where information is simply read into an active one where the capabilities of the neural circuits as a basis for information processing are fully used.”
The nanostructures can absorb light and create heat and act as containers to store and release chemicals on demand.
CREDIT
Singamaneni lab, Washington University
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Gupta P, Chandak R, Debnath A, Traner M, Watson BM, Huan H, Gholami Derami H, Baldi H, Chakrabartty S, Raman B, Singamaneni S. Augmenting Insect Olfaction Performance through Nano-Neuromodulation. Nature Nanotechnology, Jan. 25, 2024, https://doi.org/10.1038/s41565-023-01592-z
Funding for this research was provided by the Air Force Office of Scientific Research (#FA95501910394) and the Office of Naval Research (#N000142112343).
Computers can count seals from aerial photographs with lightning speed and reliability. Based on their spatial patterns, the tiny dots on the aerial images can even be assigned to one of the two major species of seals in the Wadden Sea. That is shown in the thesis that marine biologist Jeroen Hoekendijk will defend on January 26 in Wageningen. "To better understand if and how marine mammals like seals are affected by climate change and the disappearance of sea ice, this help from artificial intelligence (AI) in observations is crucial," Hoekendijk said. Hoekendijk carried out his research at the Royal Netherlands Institute for Sea Research and Wageningen University & Research.
Training AI with aerial photo’s
Harbor and grey seals in the Wadden Sea have long been counted using aerial photographs taken annually from a small aircraft. As a result, a large amount of aerial imagery is available with verified numbers of seals of both species. "We showed stacks of those old photos to a computer program and asked the computer, for example: 'find the fifty grey seals we saw in this photo'. This allowed us to train the computer program in recognizing and counting seals," Hoekendijk said.
Previously, computers were trained to count any objects by first manually marking each individual object on the images, which is a time-consuming task.
Spatial distribution
Grey and harbor seals also behave differently when lying on the sandbanks in the Wadden Sea. Harbor seals are clearly more dispersed than grey seals. "Based on that specific distribution pattern, we can now recognize and count species on images in which the resolution is too low to distinguish the species based on their external characteristics," Hoekendijk said.
Wadden Sea field lab for big Arctic
The Wadden Sea has proven to be a perfect ‘field lab’ to develop these new methodologies, according to Hoekendijk. “We can now search for and count seals on a much larger scale in, for example, the Arctic. If you don't know exactly where to look, then even looking for 7 million harp seals in the entire Arctic is like looking for needles in a haystack."
Those counts of marine mammals like harp seals in the Arctic are essential, however, Hoekendijk argues. "With the disappearance of sea ice, it is expected that seals that rest, molt and give birth to their young on that ice, will have an increasingly hard time. To know the exact consequences, we will have to find and count the animals year by year", Hoekendijk knows. The Arctic Ocean is expected to be completely ice-free possibly by the summer of 2035.
Satellite imagery
Hoekendijk expects that satellite imagery will play an increasingly important role in this work. "The resolution of satellite images is getting higher and higher. One pixel on a satellite photo measures only 31 by 31 cm nowadays. That means you can already see an individual seal from space. Added to that, 'deep learning' makes computers better and better at recognizing details. I expect that they are becoming indispensable in researching the consequences of climate change for marine mammals."
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Grey seals during the pupping season in the Dutch Wadden Sea. Jeroen Hoekendij
Walrusses in the Arctic_Photo Jeroen Hoekendijk
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Animals
Achieving sustainable urban growth on a global scale
From the impacts on the environment and climate to transforming land cover and habitats, urban growth is driving global change. Urban areas contribute up to 75% of global greenhouse gas emissions. By 2050, urban areas globally will either double or triple, and the raw materials needed to build future cities is more than the world can sustainably provide.
Yet, the impacts of cities on Earth systems are not factored into policy and planning among international agencies and that needs to change, says Karen Seto, Frederick C. Hixon Professor of Geography and Urbanization Science at the Yale School of the Environment. In a commentary recently published in Science, Seto and an international group of leading scientists called for the creation of a new urban advisory system.
Noting that more than half the world’s population live in urban areas and worldwide urban land expansion is one of the key drivers of habitat and biodiversity loss, the authors point to myriad ways that urban expansion affects global systems by putting pressure on resources, ecosystems, and the climate and emphasize the importance of scientific research in local and global decision making.
The authors advocate for the creation of an urban science panel that could support the United Nations as well as multilateral policy-making groups.
“This is about ensuring that world leaders and policymakers have the information that they need at their fingertips to design a world that reflects and responds to humanity’s urban future,” the authors wrote.
Seto, director of the Hixon Center for Urban Sustainability, is one of the world’s foremost experts on the global impacts of urbanization. She was the coordinating lead author for two U.N. climate assessment reports, the IPCC 5th (2014) and 6th (2022), and co-led the chapters on how cities can mitigate climate change. She pioneered the use of satellite remote sensing analysis to study land change and urban growth and has focused her research on how cities can play a significant role in mitigating climate change through design, low-cost energy initiatives, and sustainable transportation and building materials. To accomplish this, a coordinated effort is needed to transform existing urban science into practical guidance for international policy design for urban areas, Seto and co-authors Jessica Espey, Michael Keith, Susan Parnell, and Tim Schwanen noted.
“Cities are the nucleus from which humanities’ impact on all Earth systems can be observed. One would thus expect urban dynamics and impacts to be at the top of global governance agendas,” they wrote in the commentary.
There are existing bodies that work on cities and sustainable development goals within the U.N. and regulatory bodies within states, cities, and towns that work at the local level, but the authors stress that their focus is on singular issues or local regulations rather than at the planetary level.
“Although these existing parallel processes are important, they are failing to bring the seismic effects of urban change on the world to the attention of policy makers,” they contend.
They recommend the creation of an urban science advisory panel composed of scientists who have a clear political mandate and a requirement to submit findings to the U.N. Such a group could be rooted in an entity affiliated with the office of the U.N. secretary general or as part of the U.N.’s Multi-Stakeholder Forum on Science, Technology and Innovation for Sustainable Development Goals.
“Whatever mechanism is used, it is well past time for evidence-based dialogue on the planet-wide effects of urbanization at the highest levels of international government. Our planet’s future is an urban future, and our systems of international administration must reflect that,” the authors state.
EVEN THE «ETERNAL ICE» ON THE GRAND COMBIN IS NOT MADE TO LAST FOREVER. VISIBLE AT THE UPPER RIGHT OF THE PHOTO IS THE DRILLING CAMP OF THE 2020 ICE MEMORY EXPEDITION LED BY PSI RESEARCHER THEO JENK.
As part of the Ice Memory initiative, PSI researchers, with colleagues from the University of Fribourg and Ca’ Foscari University of Venice as well as the Institute of Polar Sciences of the Italian National Research Council (CNR), analysed ice cores drilled in 2018 and 2020 from the Corbassière glacier at Grand Combin in the canton of Valais. A comparison of the two sets of ice cores published in Nature Geoscience shows: Global warming has made at least this glacier unusable as a climate archive.
Reliable information about the past climate and air pollution can no longer be obtained from the Corbassière glacier in the Grand Combin massif, because alpine glacier melting is progressing more rapidly than previously assumed. This sobering conclusion was reached by researchers led by Margit Schwikowski, head of the Laboratory for Environmental Chemistry at PSI, and Carla Huber, PhD student and first author of the study, when they compared the signatures of particulate matter locked in the annual layers of the ice. Glaciers are invaluable for climate research. The climatic conditions and atmospheric compositions of past ages are preserved in their ice. Therefore, they can serve, in much the same way as tree rings and ocean sediments, as a so-called climate archive for research.
Normally, the amount of particle-bound trace substances in ice fluctuates with the seasons. Substances such as ammonium, nitrate, and sulfate come from the air and are deposited on the glacier through snowfall: The concentrations are high in summer and low in winter, because lower amounts of polluted air can rise from the valley when the air is cold. The 2018 ice core, which was drilled from depths of up to 14 metres during a preliminary study and contains deposits dating back to 2011, shows these fluctuations as expected. But the core from 2020, from a depth of up to 18 metres – drilled under the leadership of PSI researcher Theo Jenk – shows those fluctuations only for the upper three or four annual layers. Deeper in the ice – that is, farther in the past – the curve indicating the concentration of trace substances becomes noticeably flatter, and the total amount is lower. Schwikowski’s team reports on this in the current issue of the journal Nature Geoscience.
Washed away by meltwater
Their explanation for the observed discrepancy: Between 2018 and 2020, the glacier melting must have been so strong that an especially large amount of water from the surface penetrated into the glacier and carried the trace substances it contained into the depths. “But apparently the water there did not freeze again, concentrating the trace substances,” the environmental chemist concludes, “but instead it drained off and literally washed them away.” Of course, that distorts the signatures of the layered inclusions. The climate archive is destroyed. It is as if someone had broken into a library and not only messed up all the shelves and books, but also stole a lot of books and mixed up the individual words in the remaining ones, making it impossible to reconstruct the original texts.
The researchers examined the meteorological data from 2018 through 2020: Since there is no weather station at the top of the Grand Combin, they combined data from the surrounding stations and extrapolated it for the study area on the mountain. According to this calculation, it was warm on the glacier in line with the general climatic trend, but these years were not extreme outliers. “From this we conclude that there was no singular trigger for this strong melting, but that it resulted from many warm years in the recent past,” Schwikowski says. “It seems a threshold has been crossed, which now has led to a comparatively strong effect.”
Unexpected dynamics
The bottom line is that the example of the Grand Combin shows that the melting of glaciers is progressing more dynamically than experts had assumed. “For a long time it has been clear that the glacier tongues are retreating. But we would not have thought that the areas feeding high alpine glaciers would also be so severely affected – that is, their highest part, where the ice replenishment is formed.” So far, the researchers have examined the distribution of oxygen isotopes in the ice, which can provide information about temperature developments, and of ionic trace compounds such as ammonium, nitrate, and sulfate. Next they want to analyse to what extent the signatures of organic substances in the ice are also affected.
Ice Memory: Ice core sanctuary in Antarctica
Another reason Schwikowski is interested in this is because, together with other ice core experts from around the world, she is involved in the initiative led by the Ice Memory Foundation. The aim of this research effort is to obtain ice cores from 20 endangered glaciers around the world in 20 years and collect them in a global climate archive. The cores, cut into rods around one metre long and eight centimetres in diameter, which were individually retrieved from the depths, are to be stored permanently and securely in an ice cave at the Italian-French research station Concordia in Antarctica – managed by an international governance on the long term. The reliable temperatures near the South Pole, averaging minus 50 degrees Celsius ensure that the cores will remain usable for studies in the future, even if global warming causes all alpine glaciers to melt at some point. This is important because analysis methods are constantly improving, and future generations of scientists could extract completely different information from the ice.
The Grand Combin ice core should be one of these 20 glacier samples. “But we already realised, on the mountain, that nothing would come of it,” Schwikowski says. “As I said, the test drilling in 2018 still looked good. But several times in 2020 we came across thick, solid layers of ice that had formed in the meantime as the water melted and froze again. We encountered one such particularly thick layer at a depth of 17 to 18 metres, which was underneath a very watery, soft layer. This transition caused us enormous problems. Especially when we were drilling deeper and then pulling it out, the drill got caught in the hard layer of ice. We nearly lost this expensive device.”
“Because further attempts at other parts of the glacier saddle encountered the same layer, and the same difficulties, the researchers had to abandon the expedition. They actually wanted to drill 80 metres deep, down to the bedrock, to record the entire archive of the glacier, which spans thousands of years. But this was not possible. “And our analyses have now confirmed it,”, Schwikowski says. “At the Grand Combin, we’re already too late.”
Race against time
It is to be feared that this is also the case with other glaciers around the world that have yet to be sampled as part of Ice Memory. In the Alps, besides the Col du Dôme glacier on Mont Blanc at 4,250 metres, where the project team first drilled in 2016, there is only Colle Gnifetti on the Italian-Swiss border, which is even higher at 4,450 metres and therefore colder than the Grand Combin glacier. There the PSI team, together with the Ice Memory Foundation partners, was actually able to obtain an ice core with the signature still intact the following year. Cores from Illimani in the Bolivian Andes, from Belukha in the Russian Altai, and from Elbrus in the Caucasus have already been secured. Last year, there were also expeditions on Spitsbergen and the Col del Lys in Italy; their analyses are still pending. An expedition to Kilimanjaro, which has the only significant ice body in Africa, failed last year due to political and administrative issues.
The project is a race against time. It is by no means guaranteed to succeed. Setbacks like those at Grand Combin become more likely every year.
Text: Jan Berndorff
About PSI
The Paul Scherrer Institute PSI develops, builds and operates large, complex research facilities and makes them available to the national and international research community. The institute's own key research priorities are in the fields of matter and materials, energy and environment and human health. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, post-graduates or apprentices. Altogether PSI employs 2200 people, thus being the largest research institute in Switzerland. The annual budget amounts to approximately CHF 420 million. PSI is part of the ETH Domain, with the other members being the two Swiss Federal Institutes of Technology, ETH Zurich and EPFL Lausanne, as well as Eawag (Swiss Federal Institute of Aquatic Science and Technology), Empa (Swiss Federal Laboratories for Materials Science and Technology) and WSL (Swiss Federal Institute for Forest, Snow and Landscape Research). Insight into the exciting research of the PSI with changing focal points is provided 3 times a year in the publication 5232 - The Magazine of the Paul Scherrer Institute.
Contact
Prof. Dr. Margit Schwikowski Head of the Laboratory for Environmental Chemistry Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland Telephone: +41 56 310 41 10, e-mail: margit.schwikowski@psi.ch [German, English]
Original publication
High-altitude glacier archives lost due to climate change-related melting
C.J. Huber, A. Eichler, E. Mattea, S. Brütsch, T.M. Jenk, J. Gabrieli, C. Barbante, M. Schwikowski.
Air pollution, a critical global public health issue, includes indoor air pollution from household fossil fuel consumption, notably from gas cooking in urban areas. In urban China, where population growth and urbanization are on the rise, NO2, a byproduct of gas cooking and outdoor pollution, poses a significant health threat. A groundbreaking study reveals the significant public health benefits of transitioning from gas to electric cooking in urban China. Researchers found that such a switch could reduce the economic losses associated with diseases caused by nitrogen dioxide (NO2) exposure by 35%.
On a new study (DOI: 10.1016/j.eehl.2023.10.003) published in the journal Eco-Environment & Health, researchers from Tsinghua University used modeled NO2 exposure concentrations, exposure-response relationships with lung cancer, chronic obstructive pulmonary disease, and diabetes mellitus, and baseline DALYs to estimate the disease burden attributable to NO2 exposure in urban China in 2019. The result showed that approximately 1,675 thousand DALYs and 138 billion Chinese yuan in economic losses were attributed to NO2 in 2019. The study also estimated the potential reduction in disease burden that could be achieved by switching from gas to electric stoves for household cooking. Remarkably, transitioning from gas to electric cooking in households could reduce these losses by 35%.
"This study highlights the importance of considering both outdoor and indoor sources of NO2 exposure when assessing the health impacts of air pollution," said Prof. Zhao, lead author of the study. "Switching from gas to electric stoves is a simple and effective way to reduce NO2 exposure and improve public health."
The study's findings challenge the conventional view of gas as a clean energy source for cooking. It emphasizes the significant public health benefits of switching to electric cooking in urban settings. Furthermore, it underscores the importance of comprehensive strategies targeting both indoor and outdoor NO2 emissions to effectively mitigate pollution and its associated health risks.
Eco-Environment & Health (EEH) is an international and multidisciplinary peer-reviewed journal designed for publications on the frontiers of the ecology, environment and health as well as their related disciplines. EEH focuses on the concept of "One Health" to promote green and sustainable development, dealing with the interactions among ecology, environment and health, and the underlying mechanisms and interventions. Our mission is to be one of the most important flagship journals in the field of environmental health.
Reconsidering Gas as Clean Energy: Switching to Electricity for Household Cooking to Reduce NO2-attributed Disease Burden
‘Hell chicken’ species suggests dinosaurs weren’t sliding toward extinction
The Conversation January 25, 2024 Birdlike dinosaur Eoneophron infernalis was about the size of an adult human.
Zubin Erik Dutta
Were dinosaurs already on their way out when an asteroid hit Earth 66 million years ago, ending the Cretaceous, the geologic period that started about 145 million years ago? It’s a question that has vexed paleontologistslike us for more than 40 years.
In the late 1970s, debate began about whether dinosaurs were at their peak or in decline before their big extinction. Scientists at that time noted that while dinosaur diversity seemed to have increased in the geologic stage that spanned 83.6 million to 71.2 million years ago, the number of species on the scene seemed to decrease during the last few million years of the Cretaceous. Some researchers have interpreted this pattern to mean that the asteroid that struck the Gulf of Mexico was simply the final blowfor an already vulnerable group of animals.
However, others have argued that what looks like a decrease in the diversity of dinosaurs may be an artifact of how hard it is to accurately count them. Fossil formations might preserve different dinosaurs more or less often based on factors like their favored environment and how easily their bodies fossilized there. The accessibility of various outcrops could influence what kinds of fossils researchers have so far found. These biases are a problem because fossils are what paleontologists must rely on to conclusively answer how healthy dinosaur populations were when the asteroid hit.
At that crucial moment, what was really happening to dinosaur diversity? Discovery, identification and description of new dinosaurs provide vital clues. This is where our work comes in. Close examination of what we’d thought was a juvenile specimen of an already known species of dinosaur from this time period revealed that it was actually part of an adult from a completely new species.
Our work focusing on the life stage of our specimen demonstrates that dinosaur diversity may not have been declining before the asteroid hit, but rather that there are more species from this time period yet to be discovered – potentially even through reclassification of fossils already in museum collections.
Kyle Atkins-Weltman holds the femur of the new dinosaur as it was received, with the other fossils in the background.
Clues inside the bones of a birdlike dinosaur
Our new study focused on four hindlimb bones – a femur, a tibia and two metatarsals. They were unearthed in South Dakota, in rocks of the Hell Creek Formation, and date to the final 2 million years of the Cretaceous.
The only known species of caenagnathid from this time and region was Anzu, sometimes called the “chicken from Hell.” Covered in feathers and sporting wings and a toothless beak, Anzu was between roughly 450 and 750 pounds (200 and 340 kilograms). Despite its fearsome nickname, though, its diet is a matter of debate. It was likely an omnivore, eating both plant material and small animals.
Because our specimen was significantly smaller than Anzu, we simply assumed it was a juvenile. We chalked up the anatomical differences we noticed to its juvenile status and smaller size – and figured the animal would have changed had it continued to grow. Anzu specimens are rare, and no definite juveniles have been published in the scientific literature, so we were excited to potentially learn more about how it grew and changed throughout its lifetime by looking inside its bones.
Just like with a tree’s rings, bone records rings called lines of arrested growth. Each annual line represents part of a year when the animal’s growth slowed. They would tell us how old this animal was, and how fast or slow it was growing.
We cut through the middle of three of the bones so that we could microscopically examine the internal anatomy of the cross-sections. What we saw completely uprooted our initial assumptions.
Teal arkers point to lines of arrested growth on the cross-section of fossilized bone. Toward the outside of the bone, the lines are much closer together, reflecting less growth per year. Researchers counted exactly six lines, meaning this animal was between 6 and 7 years old when it died.
Holly Woodward
In a juvenile, we would expect lines of arrested growth in the bone to be widely spaced, indicating rapid growth, with even spacing between the lines from the inside to the outside surface of the bone. Here, we saw that the later lines were spaced progressively closer together, indicating that this animal’s growth had slowed and it was nearly at its adult size.
This was no juvenile. Instead, it was an adult of an entirely new species, which we dubbed Eoneophron infernalis. The name means “Pharaoh’s dawn chicken from Hell,” referencing the nickname of its larger cousin Anzu. Traits unique to this species include ankle bones fused to the tibia, and a well-developed ridge on one of its foot bones. These weren’t features a young Anzu would outgrow, but rather unique aspects of the smaller Eoneophron. Expanding the caenagnathid family tree
With this new evidence, we started making thorough comparisons with other members of the family to determine where Eoneophron infernalis fit within the group.
It also inspired us to reexamine other bones previously believed to be Anzu, as we now knew that more caenagnathid dinosaurs lived in western North America during that time. One specimen, a partial foot bone smaller than our new specimen, appeared distinct from both Anzu and Eoneophron. Where once there was one “chicken from Hell,” now there were two, and evidence for a third: one large (Anzu), weighing as much as a grizzly bear, one medium (Eoneophron), humanlike in weight, and one small and yet unnamed, close in size to a German shepherd.
Eoneophron infernalis and the smaller unnamed species now join the larger Anzu as late-Cretaceous caenagnathid dinosaurs from the Hell Creek region.
Zubin Erik Dutta
Comparing Hell Creek with older fossil formations such as the famous Dinosaur Park Formation of Alberta that preserves dinosaurs that lived between 76.5 million and 74.4 million years ago, we find not only the same number of caenagnathid species, but also the same size classes. There, we have Caenagnathus, comparable to Anzu, Chirostenotes, comparable to Eoneophron, and Citipes, comparable to the third species we found evidence for. These parallels in both species count and relative sizes offer compelling evidence that caenagnathids remained stable throughout the last part of the Cretaceous.
Our new discovery suggests that this dinosaur group was not declining in diversity at the very end of the Cretaceous. These fossils show that there are still new species to be discovered, and support the idea that at least part of the pattern of decreasing diversity is the result of sampling and preservation biases.
Did large dinosaurs go extinct the way a Hemingway character quipped he went broke: “gradually, then suddenly”? While there are plenty of questions still outstanding in this extinction debate, Eoneophron adds evidence that caenagnathids were doing quite well for themselves before the asteroid ruined everything. Kyle Atkins-Weltman, Ph.D. Student in Paleoecology, Oklahoma State University and Eric Snively, Associate Professor of Anatomy and Cell Biology, Oklahoma State University
