FOR PROFIT HEALTHCARE

Study finds cost benefits to system ownership of hospitals — but at a possible risk to quality

Texas A&M University

Large hospital systems control eight out of 10 hospital beds in the United States—and they continue to grow—but little has been known until now about how system ownership affects hospital operations.

To learn more, Benjamin Ukert, PhD, and Elena Andreyeva, PhD, both with the Texas A&M University School of Public Health, worked with colleagues from the University of Pennsylvania, Wharton School and Humana to study more than 100 independent hospitals that entered system ownership. Their findings were published in the Journal of Political Economy Microeconomics.

“Can large health care provider chains increase operating efficiencies while maintaining quality of care?” Ukert said. “This is the key question.”

Ukert said research in other market sectors found that stand-alone establishments gain some benefits from joining chains, such as brand reputation and access to capital and best practices. On the other hand, large organizations often raise their prices, which can reduce efficiency.

In the hospital industry, multiunit firms—or systems—now dominate, largely the result of acquiring independent hospitals in a process the researchers call corporatization. System control of the nation’s hospital beds increased from 58 percent in 2000 to 81 percent by 2020, with similar growth in the share of employment.

For their study, the researchers used four data sources from 2012 to 2018:

• Annual surveys from the American Hospital Association to track changes in hospital ownership, capital and labor inputs, operating expenses and service portfolio breadth
• Medicare fee-for-service claims and all-payer hospital discharge data from New York State to ensure a broad examination of changes in hospital quality
• Administrative claims data on individuals enrolled in employer-sponsored plans with Elevance Health (formerly Anthem), one of the largest health insurers in the United States
• Various public use files from the federal government.

The researchers compared changes in patterns at hospitals that were acquired by systems (whether originally stand-alone hospitals or those acquired from other systems) during the years studied to the patterns of hospitals that did not change ownership. They also limited their comparison hospitals to those that matched the acquired hospitals closely on attributes such as number of beds, operating cost per bed, profit type and rural county status.

“We found that system ownership leads to a price increase of 6 percent overall, with relatively large price increases in deliveries, cardiac care and respiratory care,” Ukert said. “There were two dimensions with wider variation in consumer prices: targets that were at a greater disadvantage at baseline (because of their size or price level), which appeared to benefit more from system acquisitions, and within-market deals that led to greater price increases.”

A similar differential price increase was found in cases where the target hospital was already system owned, which suggests that system ownership does not provide an advantage in price negotiations with insurers.

“This could mean that these price increases may be driven more by traditional antitrust concerns about market power rather than by increases in the target’s bargaining power,” Ukert said.

The team found no changes in patient volume at target hospitals following the transition to system ownership.

“This suggests that patient perceptions of hospital quality did not change, which aligns with what other recent studies have found,” Ukert said.

The researchers found that corporatization of hospitals does confer large operating-cost benefits to the newly acquired target hospitals that are more valuable than the increase in revenue through higher prices, mainly resulting from lower capital costs and the reduction in staffing.

“Corporatization itself improves efficiency, and larger acquirers obtain significantly greater reductions in costs when they acquire independent hospitals,” Ukert said. “For each dollar of savings on personnel expenses, expected commercial revenue is reduced by 30 cents through lower prices, and in the long run, greater corporatization should reduce market-level costs and growth in reimbursement rates for public payers as well.”

On the other hand, the study found an increase in short-term readmission rates across three different patient samples spanning multiple payers and disease groups—likely resulting from the decline in staffing—which suggests that system ownership does not improve hospital quality and may actually reduce it.

“Most studies of this type have focused on deals involving two independent hospitals in the same local market that either merge or form a new system, or include multiple types of deals, including acquisitions by systems,” Ukert said. “Our focus on corporatization gives policymakers additional considerations regarding expansions of system ownership.”

By Ann Kellett, Texas A&M University School of Public Health

---

Journal

Journal of Political Economy Microeconomics

DOI

10.1086/730454 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

The Corporatization of Independent Hospitals

 

New research reveals climate change impact on forests may be lower than expected

Plants can help stabilize soil carbon levels despite rising temperatures

University of New Hampshire

 

image: 

UNH esearchers exposed soil to continuous warming of 5°C and nitrogen fertilization of five grams per square meter per year at the Harvard Forest and found when warmer temperatures and increased nitrogen levels combined, carbon storage remained stable due to increased belowground plant inputs from roots.

view more 

Credit: University of New Hampshire

DURHAM, N.H.—(September 25, 2024)—New England’s forests confront multiple environmental challenges like rising temperatures due to climate change and increased atmospheric nitrogen deposits from burning fossil fuels. Scientists have previously studied the impact of both independently but for the first time researchers at the University of New Hampshire looked at the effects of the two together. They found that when warmer temperatures and increased nitrogen levels were combined in soil, carbon storage remained stable due to increased belowground plant inputs from roots, challenging earlier studies and suggesting that the loss of soil carbon in Northeastern forests impacted by climate change may be lower than previously predicted. 

“What is most exciting about this study is that it’s one of the longest-running experiments to look at two global change pressures instead of just focusing on one,” said Melissa Knorr, a lab research supervisor in UNH’s College of Life Sciences and Agriculture. “This is particularly important to study in the Northeast, where the region has experienced greater nitrogen deposition historically, and now faster warming than in other parts of the country.” 

The study, published in Nature Ecology & Evolution, outlines how study leads Knorr and Serita Frey, a professor in the department of natural resources and the environment, used data from a 16-year study at the Harvard Forest Long-Term Ecological Research site in Massachusetts to examine this carbon dynamic. They exposed soil at the site to continuous warming of 5°C and nitrogen fertilization of five grams per square meter per year. Previous work at the Harvard Forest site documented that soil warming alone leads to significant carbon loss in forests, whereas long-term soil nitrogen enrichment results in carbon buildup. 

“Plants, particularly through root turnover – the natural process where plant roots grow, die and decompose – and increased plant growth and activity, add new carbon to the soil,” said Frey, also a scientist with UNH’s New Hampshire Agricultural Experiment Station. “And while microbial activity breaks down organic matter, releasing CO₂, we observed that enhanced plant carbon inputs belowground – caused by warmer temperatures and increased nitrogen – help maintain soil carbon levels, counteracting what would otherwise have been a significant net loss of carbon from the soil.”  

Over the past century, New England’s average temperature has risen by 1.7°F. While research shows that rates of nitrogen deposition are declining in the region, they are still five to six times higher than pre-industrial levels. This excess nitrogen, deposited onto ecosystems through rain and snowfall, can harm forests by damaging plant health and acidifying waterways.

Researchers say the findings of this study highlight the importance of plant-soil interactions in forest ecosystems and how these processes could be key to managing forests and ensuring that they continue to act as carbon sinks by absorbing CO₂ and reducing its concentration in the atmosphere.

“By challenging previous predictions from studies that looked at only one factor alone, this research offers a fuller picture of how ecosystems respond to multiple stressors and forests’ role in combating climate change,” said Knorr. “The study offers insights that could inform conservation strategies to enhance carbon sequestration and preserve forest health across the Northeast.” 

Co-authors include Alexandra Contosta, Eric Morrison and Thomas Muratore, all with UNH; Mark Anthony, University of Vienna; Kevin Geyer, Allegheny College; Luliana Stoica and Myrna Simpson both from the University of Toronto Scarborough.

###

About UNH
The University of New Hampshire inspires innovation and transforms lives in our state, nation and world. More than 16,000 students from 50 states and 87 countries engage with an award-winning faculty in top-ranked programs in business, engineering, law, health and human services, liberal arts and the sciences across more than 200 programs of study. A Carnegie Classification R1 institution, UNH partners with NASA, NOAA, NSF, and NIH, and received over $210 million in competitive external funding in FY23 to further explore and define the frontiers of land, sea and space.
 

---

Journal

Nature Ecology & Evolution

Scientists’ win-win solutions to global nitrogen crisis are good for the pocket and planet

UK Centre for Ecology & Hydrology

 

image: 

The new international guidance document, Nitrogen mitigation, goes beyond agriculture, which is the largest consumer and emitter of nitrogen, to consider all economic sectors, and addresses the issue on a global scale.

view more 

Credit: INMS

• 
  

• 200bn tonnes of nitrogen are lost to environment globally every year, equivalent to up to $300bn (US dollars).

• Online toolkit outlines range of sustainable practices for different sectors to cut pollution of air, water, soils.

The most comprehensive scientific review of the global nitrogen cycle has outlined 150 ‘win-win’ measures to significantly reduce nitrogen pollution while saving billions in costs across a range of industries.

The solutions have been put forward by a team of 50 international experts, led by the UK Centre for Ecology & Hydrology (UKCEH), in a new guidance document for the United Nations. They aim to address the problem of excessive nitrogen leakage that is damaging our oceans, lakes, air and soils, while improving food security and reducing costs for business.

Nitrogen, an essential nutrient for life, is present in human and animal excreta and synthetic fertilisers, as well as being a byproduct of fuel combustion processes. However, inefficient management in sectors such as agriculture, transport, wastewater treatment and aquaculture, means around 80% of reactive nitrogen resources escape into the environment.

Nitrogen in its various forms – including ammonia, nitrogen oxides, nitrate and nitrous oxide – can result in poor air quality that threatens human health, toxic algal blooms that cause the death of plants and fish in oceans and lakes, and increased climate change.

Providing a toolkit

The new international guidance document, Nitrogen mitigation, goes beyond agriculture, which is the largest consumer and emitter of nitrogen, to consider all economic sectors, and addresses the issue on a global scale.

The authors have also produced an online toolkit, the Nitrogen Measures Database, which is designed to be used alongside the guidance document and provides further detail on each measures including ‘how to implement’ and the cost, benefits and risks of implementing each measure. This will support policymakers and stakeholders to select the most suitable measures for their specific requirements and ambitions.

The international guidance document considers synergies and trade-offs between actions and features case studies to demonstrate how a package of measures can be selected.

Key recommendations

The recommended actions include:

• Improved fertiliser use. More efficient storage and application of organic and synthetic fertilisers, which would reduce pollution, energy consumption and costs for farmers.
• Sustainable farming practices. Using cover crops and reducing tillage to retain nitrogen in soils. Integrating livestock and arable farming where possible. Keeping animal housing clean.
• Natural filtration systems. Constructing wetlands to keep nitrogen pollution out of lakes and rivers.
• Nitrogen recovery. Improving treatment of sewage and food waste to recover nitrogen, which can then be added as a fertiliser to fields.
• Sustainable fish farming. Applying nutrient-rich sludge from fish farms to agricultural land as a fertiliser using low-emission techniques.
• Reducing transport emissions. Increasing the use of electric vehicles and improving fuel combustion processes, and recovering nitrogen oxides for their nitrogen value.
• Dietary changes. Cutting food waste and consumption of animal products with high nitrogen footprints.
• Energy generation from organic residues. Using anaerobic digestion to process manure and aquaculture sludge into biogas, with the byproducts retained for use as fertiliser.

The cost of nitrogen waste

Scientists estimate 200 billion tonnes of nitrogen is lost to the environment globally every year, which, if equated with the wastage of the same amount of fertiliser, is equivalent to a loss of up to 300 billion US dollars at current prices.

Benefits for people and planet

Dr Will Brownlie, lead author of Nitrogen mitigation, says: “Improving nitrogen management offers a remarkable opportunity to not only enhance environmental health but also strengthen the global economy. The key lies in adopting an integrated approach across the entire nitrogen cycle, ensuring that all sectors involved have access to the diverse strategies available to improve nitrogen sustainability.”

The guidance document, produced by scientists representing 40 institutes in 21 countries, points out that sustainable nitrogen management is crucial to achieving most of the UN Sustainable Development Goals.

Retaining more nitrogen within the agricultural system would improve food security, especially in regions where nutrient-poor soils limit crop production.

Sustainable management of nitrogen would also help mitigate climate change, by reducing nitrous oxide emissions.

Circular economy

The report advocates using data collection, satellite monitoring and artificial intelligence, combined with smartphone technologies, to provide accurate, site-specific nitrogen management guidance.

Professor Mark Sutton of UKCEH, who leads the International Nitrogen Management System (INMS) emphasises: "We are delivering innovative science-based guidance for the UN to accelerate uptake globally. Our vision is for a circular nitrogen economy that wastes less of this precious resource, reducing the costs to governments, farmers and wastewater companies, while boosting farmers’ incomes."

Isabelle van der Beck of the United Nations Environment Programme (UNEP) adds: "INMS is highlighting the importance of nitrogen as as a multi-dimensional challenge that links all economic sectors. We see this as a way to mobilise efforts to reduce international water pollution, so we can simultaneously benefit air, climate, biodiversity and the economy."

- Ends -

Notes to Editors

About the guidance document

Nitrogen mitigation has been produced as part of the International Nitrogen Management System (INMS) initiative.
 
The Nitrogen Measures Database, which is designed to be used alongside the Nitrogen Mitigation guidance document, is available here.   

INMS comprises around 80 partners globally, providing evidence on the nitrogen cycle, impacts of pollution and solutions. It is funded through the Towards INMS project by the Global Environment Facility (GEF), through the United Nations Environment Programme (UNEP).

The INMS Guidance Document and online tool will be launched on 25 September 2024 at the 10th International Waters Conference (IWC10) organised by the GEF, which runs 23-26 September at Punte del Este, Montevideo, Uruguay.

About nitrogen

Nitrogen is a naturally occurring element that is essential for life. Unreactive nitrogen gas (N2) makes up 78 per cent of the air we breathe. 

However, in reactive forms, it is a pollutant of air, water and soils:

• Gases such as ammonia (NH3) and nitrogen oxides (NOx) are key components of particulate matter, thereby contributing to poor air quality which can aggravate respiratory and heart conditions, leading to premature deaths.
• Nitrate from chemical fertilisers, manure and industry pollutes rivers, seas and soils posing a health risk for humans, fish, aquatic organisms and plant life.
• Nitrous oxide (N2O) is a greenhouse gas that depletes the ozone layer and is 260 times more powerful than carbon dioxide

 

Harvests, wildfires, epidemics: How the jet stream has shaped extreme weather in Europe for centuries

Tree-ring data reveal that periodic shifts in strong winds high above the Earth's surface have driven opposite climates in different parts of Europe for the past 700 years and likely much longer

University of Arizona

 

image: 

Members of the research team collected tree ring samples at various locations in Europe, including the Balkan region. 

view more 

Credit: Courtesy of Valerie Trouet

During her summer travels to her native Belgium, University of Arizona professor Valerie Trouet noticed something that turned casual curiosity into a major scientific discovery: When the sun hid behind an overcast sky and people around her put on sweaters instead of summer clothes, the weather tended to be warm and dry in Italy, Greece and the Balkans, popular summer escapes for tourists from the cooler climates of central and northern Europe.

At U of A's Laboratory of Tree-Ring Research, Trouet studies tree-rings to gather clues about what past climates were like, reading wavy, wooden lines like a linguist might decipher an ancient text. What if, she mused, the key to understanding the capricious summers in Europe could be hidden in trees, silent witnesses to centuries of warm and cold, sunshine, rain and snow?

Trouet assembled an international collaboration to collect tree-ring samples across Europe. The team published its results – the first reconstruction of the jet stream over the past 700 years – on Tuesday in the journal Nature.

The jet stream and the Black Death

Jet streams are concentrated bands of wind in the upper atmosphere that travel around the globe in the northern and southern hemispheres. Their exact locations are not fixed; in response to changes in the position and intensity of high- and low-pressure weather systems, they may shift north or south or change their course, resembling a swiftly running stream at some times, and a slow, meandering river at others.

The jet stream, it turns out, largely determines summer climate in Europe, and it does so in a seesaw-type pattern that climate researchers call a "dipole."

"When the jet stream is in an extreme northern position, we get cooler and wetter conditions over the British Isles and warmer and drier conditions over the Mediterranean and the Balkans," explained study co-author Ellie Broadman, a former postdoctoral research fellow at Laboratory of Tree-Ring Research who is now a biologist at the Sequoia-Kings Canyon Field Station of the U.S. Geological Survey. "This is related to the climate conditions we are witnessing right now, such as catastrophic flooding in central Europe."

Hotter conditions over the Balkans cause more moisture than normal to evaporate from the Mediterranean Sea and rain down further north. Conversely, when the jet stream migrates further south, it drags warmer and drier air over the British Isles and pushes cooler temperatures and more moisture toward southeastern Europe.

Measurements of the jet stream have only been around since the late 1940s, Trouet said. By using tree-ring samples from across Europe as proxies for temperature, the research team was able to reconstruct jet stream variation over the past 700 years.

Each year, trees add a ring consisting of less dense wood in the spring and denser wood in the summer. By analyzing tree rings under the microscope, dendrochronologists can compile an archive of past climates. 

"We link tiny, subcellular cell wall features in the wood to atmospheric winds that weave through the atmosphere many miles above the Earth, which is fascinating," Trouet said.

Remarkably, the team found past patterns of the jet stream reflected on a societal level, recorded in historic documents.

"Europe has a long history of writing things down," Trouet said. "For example, there were monks in Ireland who started recording storms that happened in the 600s, the early Middle Ages, and you have centuries-long records of grape harvests, grain prices and epidemics."

By comparing historical records to the jet stream reconstruction, Trouet's team discovered that the climate dipole created by the jet stream has influenced European society for the past 700 years and likely much longer.

"Epidemics happened more frequently in the British Isles when the jet stream was further north," Trouet said. "Because summers were wet and cold, people stayed indoors, and the conditions were more conducive to spreading diseases."

From 1348 to 1350, the plague, known as the Black Death, raged in Ireland. At that time, the jet stream was in an extreme, far-north position over Europe.

The findings provide critical data to improve climate models that researchers rely on to predict future climate, Broadman said. Much research has focused on how the jet stream is affected as a result of global warming.

"It's hard to do that if you only have 60 years' worth of data, which is why a reconstruction going back 700 years is very useful," she said. "It allows you to actually compare the past to what's been happening since we started putting greenhouse gasses into the atmosphere."

Harvest failures, wildfires and extreme weather

Scientists have observed a trend showing the jet stream is gradually shifting northward, independent of its seasonal or more short-term variations.

"When you combine our reconstruction with harvest failures, you see that this trend likely leads to issues with major cereal crops and other types of weather extremes," Trouet said. "It gives you a preview of the kinds of extreme events and societal outcomes we could expect if that trajectory continues."

The findings also set a precedent for a future trajectory of jet stream variation and extreme weather events, such as wildfires, Trouet said.

"We showed that wildfires in the Balkans historically happened substantially more when the jet stream was in that northern position that creates dry and hot conditions," she said. "And that is exactly what we're seeing this summer. The results that we're seeing in our reconstruction act out in real life."

"When you look at how the jet stream's natural variability alone has impacted societies, you can get an idea of what might happen if you add more heat in the atmosphere and more variability," Broadman added. "Being able to say, 'OK, maybe we need to watch out for this or that particular jet stream configuration' can be very helpful for predictions of climate related extremes."

 

Wood samples from the Balkan region were among those analyzed for this study.

In Scotland, where virtually no living trees going back many hundreds of years are left, the team collected subfossil wood from lake bottoms for dendrochronological analysis in the lab.

Credit

Courtesy of Valerie Trouet

---

Journal

Nature

DOI

10.1038/s41586-024-07985-x 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Jet stream controls on European climate and agriculture since 1300 CE

Article Publication Date

25-Sep-2024

 

Encoding human experience: Study reveals how brain cells compute the flow of time

UCLA researchers say findings could have implications for improving memory, cognitive functions and artificial intelligence

University of California - Los Angeles Health Sciences

A landmark study led by UCLA Health has begun to unravel one of the fundamental mysteries in neuroscience – how the human brain encodes and makes sense of the flow of time and experiences.

The study, published in the journal Nature, directly recorded the activity of individual neurons in humans and found specific types of brain cells fired in a way that mostly mirrored the order and structure of a person’s experience. They found the brain retains these unique firing patterns after the experience is concluded and can rapidly replay them while at rest. Furthermore, the brain is also able to utilize these learned patterns to ready itself for future stimuli following that experience. These findings provide the first empirical evidence regarding how specific brain cells integrate “what” and “when” information to extract and retain representations of experiences through time.

The study’s senior author, Dr. Itzhak Fried, said the results could serve in the development of neuro-prosthetic devices to enhance memory and other cognitive functions as well as have implications in artificial intelligence’s understanding of cognition in the human brain.

“Recognizing patterns from experiences over time is crucial for the human brain to form memory, predict potential future outcomes and guide behaviors,” said Fried, director of epilepsy surgery at UCLA Health and professor of neurosurgery, psychiatry and biobehavioral sciences at the David Geffen School of Medicine at UCLA. “But how this process is carried out in the brain at the cellular level had remained unknown – until now.”

Previous research, including by Dr. Fried, used brain recordings and neuroimaging to understand how the brain processes spatial navigation, showing in animal and human models that two regions of the brain – the hippocampus and the entorhinal cortex – played key roles. The two brain regions, both important in memory functions, work to interact to create a “cognitive map." The hippocampal neurons act as "place cells" that show when an animal is at a specific location, similar to an 'X' on a map, while the entorhinal neurons act as "grid cells" to provide a metric of spatial distance. These cells found first in rodents were later found in humans by Fried’s group.

Further studies have found similar neural actions work to represent non-spatial experiences such as time, sound frequency and characteristics of objects. A seminal finding by Fried and his colleagues was that of “concept cells” in human hippocampus and entorhinal cortex that responds to particular individuals, places or distinct objects and appear to be fundamental to our ability for memory.  

To examine the brain processing of events in time, the UCLA study recruited 17 participants with intractable epilepsy who had been previously had depth electrodes implanted in their brains for clinical treatment.

Researchers recorded the neural activity of the participants as they underwent a complex procedure that involved behavioral tasks, pattern recognition and image sequencing.

Participants first underwent an initial screening section during which approximately 120 images of people, animals, objects and landmarks were repeatedly shown to them on a computer over about 40 minutes. The participants were instructed to perform various tasks such as determining whether the image showed a person or not. The images, of things like famous actors, musicians and places, were selected partly based on each participant’s preferences.

Following this, the participants underwent a three-phase experiment in which they would perform behavioral tasks in response to images that were arbitrarily displayed on different locations of a pyramid-shaped graph. Six images were selected for each participant.

In the first phase, images were displayed in a pseudo-random order. The next phase had the order of images determined by the location on the pyramid graph. The final phase was identical to the first phase. While watching these images, the participants were asked to perform various behavioral tasks that were unrelated to the positioning of the images on the pyramid graph. These tasks included determining whether the image showed a male or female or whether a given image was mirrored compared to the previous phase.

In their analyses, Fried and his colleagues found the hippocampal-entorhinal neurons gradually began to modify and closely align their activity to the sequencing of images on the pyramid graphs. These patterns were formed naturally and without direct instruction to the participants, according to Fried. Additionally, the neuronal patterns reflected the probability of upcoming stimuli and retained the encoded patterns even after the task was completed.

Lead author of the study was Pawel Tacikowski with co-authors Guldamla Kalendar and Davide Ciliberti.

“This study shows us for the first time how the brain uses analogous mechanisms to represent what are seemingly very different types of information: space and time,” Fried said. “We have demonstrated at the neuronal level how these representations of object trajectories in time are incorporated by the human hippocampal-entorhinal system.”

Article: Human hippocampal and entorhinal neurons encode the temporal structure of experience, Tacikowski et al., Nature, 2024, https://doi.org/10.1038/s41586-024-07973-1

---

Journal

Nature

DOI

10.1038/s41586-024-07973-1 

Subject of Research

People

Article Title

Human hippocampal and entorhinal neurons encode the temporal structure of experience

Article Publication Date

25-Sep-2024

 

Brazilian fossils reveal jaw-dropping discovery in mammal evolution

University of Bristol

 

image: 

Riograndia and Brasilodon

view more 

Credit: Jorge Blanco

These fossils, belonging to the mammal-precursor species Brasilodon quadrangularis and Riograndia guaibensis, offer critical insights into the development of the mammalian jaw and middle ear, revealing evolutionary experiments that occurred millions of years earlier than previously thought.

Mammals stand out among vertebrates for their distinct jaw structure and the presence of three middle ear bones. This transition from earlier vertebrates, which had a single middle ear bone, has long fascinated scientists. The new study explores how mammal ancestors, known as cynodonts, evolved these features over time.

Using CT scanning, researchers were able to digitally reconstruct the jaw joint of these cynodonts for the first time. The researchers uncovered a ‘mammalian-style’ contact between the skull and the lower jaw in Riograndia guaibensis, a cynodont species that lived 17 million years before the previously oldest known example of this structure, but did not find one in Brasilodon quadrangularis, a species more closely related to mammals. This indicates that the defining mammalian jaw feature evolved multiple times in different groups of cynodonts, earlier than expected.

These findings suggest that mammalian ancestors experimented with different jaw functions, leading to the evolution of 'mammalian' traits independently in various lineages. The early evolution of mammals, it turns out, was far more complex and varied than previously understood.

Lead author James Rawson based in Bristol’s School of Earth Sciences explained: "The acquisition of the mammalian jaw contact was a key moment in mammal evolution.

"What these new Brazilian fossils have shown is that different cynodont groups were experimenting with various jaw joint types, and that some features once considered uniquely mammalian evolved numerous times in other lineages as well.”

This discovery has broad implications for the understanding of the early stages of mammal evolution, illustrating that features such as the mammalian jaw joint and middle ear bones evolved in a patchwork, or mosaic, fashion across different cynodont groups.

Dr. Agustín Martinelli, from the Museo Argentino de Ciencias Natural of Buenos Aires, stated: “Over the last years, these tiny fossil species from Brazil have brought marvellous information that enrich our knowledge about the origin and evolution of mammalian features. We are just in the beginning and our multi-national collaborations will bring more news soon.”

The research team is eager to further investigate the South American fossil record, which has proven to be a rich source of new information on mammalian evolution.

Professor Marina Soares of the Museu Nacional, Brazil, stated: “Nowhere else in the world has such a diverse array of cynodont forms, closely related to the earliest mammals.”

By integrating these findings with existing data, the scientists hope to deepen their understanding of how early jaw joints functioned and contributed to the development of the mammalian form.

James added: “The study opens new doors for paleontological research, as these fossils provide invaluable evidence of the complex and varied evolutionary experiments that ultimately gave rise to modern mammals.”

 

Paper:

‘Brazilian fossils reveal homoplasy in the oldest mammalian jaw joint’ by James Rawson et al in Nature.

VIDEP

https://www.eurekalert.org/multimedia/1042939

https://www.eurekalert.org/multimedia/1042940

---

Journal

Nature

Method of Research

Computational simulation/modeling

Subject of Research

Animals

Article Title

Brazilian fossils reveal homoplasy in the oldest mammalian jaw joint

Article Publication Date

25-Sep-2024

Disclaimer: AAAS and E