Thursday, February 20, 2025

The inner ear of Neanderthals reveals clues about their enigmatic origin

New study challenges the theory that Neanderthals originated after an evolutionary event that implied the loss of part of their genetic diversity

Peer-Reviewed Publication

Institut Català de Paleontologia Miquel Crusafont

Life appearance of a male Neanderthal — image:
Life appearance reconstruction of a Neanderthal male at the Natural History Museum of London. (Photo: Allan Henderson under CC BY 2.0)
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Credit: Photo: Allan Henderson, under CC BY 2.0

Neanderthals emerged around 250.000 years ago from European populations—referred to as "pre-Neanderthals"—which inhabited the Eurasian continent between 500.000 and 250.000 years ago. It was long believed that no significant changes occurred throughout the evolution of Neanderthals, yet recent paleogenetic research based on DNA samples extracted from fossils revealed the existence of a drastic genetic diversity loss event between early Neanderthals (or ancient Neanderthals) and later ones (also referred to as "classic" Neanderthals). Technically known as a "bottleneck", this genetic loss is frequently the consequence of a reduction in the number of individuals of a population. Paleogenetic data indicate that the decline in genetic variation took place approximately 110,000 years ago.

The presence of an earlier bottleneck event related to the origin of the Neanderthal lineage was also a widespread assumption among the scientific community. As such, all hypotheses formulated thus far were based on the idea that the earliest Neanderthals exhibited lower genetic diversity than their pre-Neanderthal ancestors, as consequence of a bottleneck event. However, the existence of a bottleneck at the origin of the Neanderthals has not been confirmed yet through paleogenetic data, mainly due to the lack of genetic sequences old enough to record the event and needed for ancient DNA studies.

In a study led by Alessandro Urciuoli (Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona) and Mercedes Conde-Valverde (Cátedra de Otoacústica Evolutiva de HM Hospitales y la Universidad de Alcalá), researchers measured the morphological diversity in the structure of the inner ear responsible for our sense of balance: the semicircular canals. It is widely accepted that results obtained from studying the morphological diversity of the semicircular canals are comparable to those obtained through DNA comparisons.

The study focused on two exceptional collections of fossil humans: one from the Sima de los Huesos site of Atapuerca (Burgos, Spain), dated to 430,000 years old, which constitutes the largest sample of pre-Neanderthals available in the fossil record; and another from the Croatian site of Krapina, this representing the most complete collection of early Neanderthals and dated to approximately 130.000-120.000 years ago. The researchers calculated the amount of morphological diversity (i.e., disparity) of the semicircular canals of both samples, comparing them with each other and with a sample of classic Neanderthals of different ages and geographical origins.

The study's findings reveal that the morphological diversity of the semicircular canals of classic Neanderthals is clearly lower than that of pre-Neanderthals and early Neanderthals, which aligns with previous paleogenetic results. Mercedes Conde-Valverde, co-author of the study, emphasized the importance of the analyzed sample: “By including fossils from a wide geographical and temporal range, we were able to capture a comprehensive picture of Neanderthal evolution. The reduction in diversity observed between the Krapina sample and classic Neanderthals is especially striking and clear, providing strong evidence of a bottleneck event.”

On the other hand, the results challenge the previously accepted idea that the origin of Neanderthals was associated with a significant loss of genetic diversity, prompting the need to propose new explanations for their origin. “We were surprised to find that the pre-Neanderthals from the Sima de los Huesos exhibited a level of morphological diversity similar to that of the early Neanderthals from Krapina,” commented Alessandro Urciuoli, lead author of the study. “This challenges the common assumption of a bottleneck event at the origin of the Neanderthal lineage,” the researcher stated.

Alessandro Urciuoli is a postdoctoral fellow at the University of Zurich (previously employed at the Universitat Autònoma de Barcelona as a Margarita Salas postdoctoral fellow) and associated researcher at the Institut Català de Paleontologia Miquel Crusafont; Mercedes Conde-Valverde is lecturer at the Universidad de Alcalá and director of the Cátedra de Otoacústica Evolutiva de HM Hospitales and the Universidad de Alcalá.

Schematic representation of the changes in morphological diversity along the evolutionary history of the Neanderthal clade. Sima de los Huesos and, particularly, Krapina populations show similarly large amounts of morphological variation, thus suggesting continuity during the Middle Pleistocene. Later, classic Neanderthals instead appear much less diverse, hence hinting for the presence of a drop in phenotypic variation right after the temperature maximum reached around 120.000 years ago, and at the beginning of the Last Glacial cycle.

Credit

Alessandro Urciuoli (Institut Català de Paleontologia Miquel Crusafont)

Artwork on the schematical representation of the distribuition of morphological variation of th inner ear along time in Neanderthals

Credit

Alessandro Urciuoli (Institut Català de Paleop

Journal

Nature Communications

DOI

10.1038/s41467-025-56155-8

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Semicircular canals shed light on bottleneck events in the evolution of the Neanderthal clade

Article Publication Date

20-Feb-2025

Describing previously unknown aspects of Copper Age ceremonial clothing

University of Seville

Researchers from the University of Seville have led a study that analysed the perforated beads discovered in the Tholos de Montelirio, part of the Copper Age mega-site of Valencina de la Concepción-Castilleja de Guzmán (Seville). The conclusions of their work, published in the journal Science Advances, highlight the importance of the ceremonial clothing and its symbolism.

The garments worn by the women buried in the Montelirio tholos were made using perforated beads and probably linen fibre to bind them together. They were ceremonial garments which, in at least two cases, were full-length tunics. These robes were also ornamented with ivory and amber pendants representing acorns, birds and other, unidentifiable, items. The radiocarbon dating study reveals that these robes were manufactured at the same time as the Montelirio burials were made, between 2800 and 2700 BC.

The materials found at Montelirio constitute the largest collection of perforated beads ever documented in a single tomb. A quantification of the collection, which is currently conserved at the Archaeological Museum of Seville, has found that some 270,000 of these beads have been found to date. This makes Montelirio the largest collection of such objects discovered anywhere in the world.

These beads, with an average diameter of between 2 and 5 millimetres, were mostly made from the shells of marine molluscs of the Pectinidae and Cardidiae families. Of these, the popular ‘scallop’ shells stand out; they are known today as the symbol of the apostle St. James and the famous pilgrimage route associated with him, but which in antiquity were the symbol of the goddess Venus/Aphrodite. The results of the experimental study show that, in total, more than 800 kilogrammes of these shells were used, which had to be collected from the coasts and beaches that 5000 years ago stretched along what is now the lower Guadalquivir Valley and its marshes.

The garments had a strongly symbolic meaning, given the marine nature of the raw material used and their intense white colour. Dressed in them, and probably ornamented (perhaps painted) with red cinnabar pigment, which is found in abundance in the same tomb, these women performed tasks of religious and probably political leadership in their time, managing a famous sanctuary around which important congregations of great social significance took place.

An extensive study carried out over the last five years - including meticulous quantification of the collection, characterisation of raw materials, radiocarbon dating and statistical chronometric modelling, morphometric analysis, phytolith analysis, experimental work and contextual analysis – has revealed several new features of these remarkable creations. The role of the garments as sumptuary attributes loaded with symbolism, used by a selected group of women of high social position, underlines the extraordinary role that the mega-site of Valencina played 5,000 years ago as a central social, political and religious place, a reference for a wide range of communities distributed throughout the Guadalquivir Valley and, more generally, the south of the Iberian Peninsula.

The work, led by researchers from the University of Seville’s Atlas Group features eighteen specialists from various national and international scientific institutions, including the Spanish Institute of Oceanography (IEO-CSIC), the universities of La Laguna, Huelva, Granada and Basque Country (Spain), Southampton and Durham (UK) and Northwestern (USA), as well as the Municipal Museum of Valencina de la Concepción (Seville).

Journal

Science Advances

DOI

10.1126/sciadv.adp1917

Article Title

A multi-analytical study of the Montelirio beaded attires: Marine resources, sumptuary crafts, and female power in copper age Iberia

Scientists call for efforts to protect habitats of critically endangered shark species

University of Plymouth

A critically endangered species of shark could be forced to adapt to new habitats – or face extinction – as a result of changes in the ocean predicted to occur as a result of climate change, a new study has suggested.

The whitefin swellshark (Cephaloscyllium albipinnum) is a species of catshark found in deeper waters just off Australia’s south and east coasts. Its precise population numbers are uncertain, but the species has been assessed by the International Union for Conservation of Nature (IUCN) as Critically Endangered for a number of years due to declines largely attributed to fishing practices.

The new study, by researchers at the University of Plymouth, suggests that degrees of ocean change – including higher sea temperatures and shifts in ocean chemistry – predicted to occur by the end of this century could heighten its vulnerability.

Using a range of computer modelling, which accounted for the species’ favoured habitats and forecast ocean conditions, researchers found that up to 70% of currently suitable habitats will be lost over the next 75 years. There is predicted to be an area within the Great Australian Bight that could offer whitefin swellshark populations refuge, with favourable ocean conditions and sources of the food they need to survive.

The only challenges with that, based on current knowledge of the species’ whereabouts, are that the sharks – which grow to around 1.1-metres long – may need to move anywhere between 70km and 1100km in order to reach their potential new home. And it is likely they will not be the only species seeking refuge in the area, with a number of other marine species also likely to be forced to migrate polewards as they look to leave areas impacted by climate change.

Writing in the journal PeerJ, the researchers say the vulnerability of the species to the future effects of climate change is clear. However, they do believe there is cause for hope, with Australia being one of the world’s more proactive nations when it comes to implementing conservation measures and management strategies, such as marine protected areas (MPAs).

The study was carried out by Kerry Brown, a BSc (Hons) Marine Biology and Oceanography graduate from the University of Plymouth, as part of her undergraduate dissertation. She said: “Most people will probably have never seen them, but whitefin swellsharks are an incredibly pretty species. However, despite them being listed as critically endangered, we actually know very little about their behaviour given its habitats are deep in the ocean. What we do know is that they have been on our planet for a very long time, so will have had to adapt to changes in their environment before. However, the threat to their future survival now is very real unless we take urgent steps to protect them.”

Dr Robert Puschendorf, Associate Professor in Conservation Biology at the University of Plymouth, supervised the study and previously spent a decade working in Australia.

He added: “We have seen species move into different areas of the ocean in the past, so that offers some sense of hope for the whitefin swellshark. And the marine protected areas along the Australian coast are certainly a positive factor, although whether they are in the right place for this particular species is another matter. However, it does show the authorities in the region have the willingness and means to take action. The challenges faced by this – and other – species are now very different to what they may have encountered in the past, when you consider there are now very few parts of the planet that humans haven’t damaged in some way. But our study shows we are potentially in a position where we can do something about it.”

Journal

PeerJ

DOI

10.7717/peerj.18787

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Future climate-driven habitat loss and range shift of the Critically Endangered whiteûn swellshark (Cephaloscyllium albipinnum)

Article Publication Date

20-Feb-2025

DEI/CRT

New ACS study shows cancer mortality rates among Black people declining, but remain higher than other racial and ethnic groups

American Cancer Society

The American Cancer Society (ACS) today released Cancer Statistics for African American and Black People, 2025. According to the report, the cancer mortality rate declined from 1991 to 2022 by 49% and 33% in Black men and women, respectively, in the United States. However, African American and Black people continue to have a disproportionately elevated cancer burden compared to other population groups. According to the study, the risk of cancer death for Black individuals is two-fold that of White individuals for myeloma, prostate, uterine corpus (endometrial), and stomach cancers, and 40%-50% higher for colorectal, breast, cervical, and liver cancers. Similarly, survival is lower in Black people than in White people for almost every type and stage of cancer, with the largest gaps for melanoma, uterine corpus, and cervical cancers. These important findings are published in CA: A Cancer Journal for Clinicians and available on cancer.org.

“Overall declines in cancer mortality rates in Black people largely reflect behavioral changes, such as historical declines in cigarette smoking among Black teens, as well as advances in treatment and earlier detection for some cancers,” said Rebecca Siegel, senior scientific director, surveillance research at the American Cancer Society, and senior author of the report. “Yet, this population persistently experiences a much higher mortality burden than other racial and ethnic groups for many cancers. We must reverse course.”

For the study, ACS investigators compiled the most recent data on cancer incidence, mortality, survival, screening, and risk factors for Black people using population-based science from the National Cancer Institute and the U.S. Centers for Disease Control and Prevention. Black people represent the third largest racial and ethnic group in the country after White and Hispanic people, accounting for approximately 14% of the total population in 2022. This year, there will be an estimated 248,470 new cancer diagnoses and 73,240 cancer deaths among this population. Cancer is the second-leading cause of death in Black men and women after heart disease.

"This report highlights the disparities the Black community has faced for decades. While the decline in cancer mortality rates is encouraging, the stark inequities in incidence and survival for many cancers underscore the urgent need for targeted research and interventions,” said Dr. Wayne A. I. Frederick, interim chief executive officer of the American Cancer Society and the American Cancer Society Cancer Action Network (ACS CAN). “This is a critical opportunity for the scientific, clinical, and policy-making community to come together to drive meaningful change. Together we must inform strategies to close these gaps, improve early detection, and ensure equitable access to life-saving treatments for the Black community.”

Other highlights in the report include:

Black men experienced the most significant relative decline in cancer mortality from 1991 to 2022 (compared to Black women and White men and women) at nearly every age, including a 65%-67% drop among those 40-59 years of age.
The most commonly diagnosed cancers continue to be prostate (44% among males), breast (34% among females), lung (10%), and colorectal (8%), which will account for 58% of all new cancers diagnosed among Black people.
Black men have a 67% higher prostate cancer incidence rate compared to White men and are more than twice as likely to die from the disease.
Black women have a 38% higher likelihood of dying from breast cancer compared to White women despite a 5% lower likelihood of being diagnosed with the disease.
Uterine corpus (endometrial) cancer incidence continues to increase in Black women by 2% per year.

“Future research should not only explore the influence of systemic racism on health, but also develop mechanisms to implement change, including increasing diversity in clinical trials,” added Dr. William Dahut, chief scientific officer at the American Cancer Society. “Given this latest data, it’s also more important than ever to understand how to reduce your chance of getting cancer. This means taking preventative health measures, like understanding your risk profile, maintaining a healthy lifestyle, and keeping up on cancer screenings to catch the disease as early as possible.”

To address ongoing cancer disparities in Black women, last year ACS launched the VOICES of Black Women study. The study is designed to help better understand the multi-level drivers of incidence, mortality, and resilience of cancer and other health conditions among Black women in the U.S., so we can collectively address them. It will be the largest cohort study of cancer risk and outcomes among Black women in the U.S. For more information and to participate, visit voices.cancer.org.

Other ACS researchers participating in the study include lead author Anatu Saka, Angela Giaquinto, Dr. Lauren McCullough, and Dr. Ahmedin Jemal.

Additional ACS Resources:

# # #

About the American Cancer Society
The American Cancer Society is a leading cancer-fighting organization with a vision to end cancer as we know it, for everyone. For more than 110 years, we have been improving the lives of people with cancer and their families as the only organization combating cancer through advocacy, research, and patient support. We are committed to ensuring everyone has an opportunity to prevent, detect, treat, and survive cancer. To learn more, visit cancer.org or call our 24/7 helpline at 1-800-227-2345. Connect with us on Facebook, X, and Instagram.

Journal

CA A Cancer Journal for Clinicians

Politecnico di Milano and Georgia Tech unveil new scenarios for asteroid deflection

Politecnico di Milano

Milan, February 20, 2025 – How prepared are we to deflect an asteroid heading towards Earth? This question is answered by two studies just published in Nature Communications, the result of a collaboration between Politecnico di Milano, Georgia Institute of Technology and other international institutions. The research analyses the historical results of NASA's DART (Double Asteroid Redirection Test) mission, which hit the asteroid Dimorphos on September 26, 2022, marking the first practical demonstration of planetary defence.

The impact, observed through ground and space-based telescopes as Hubble, produced a huge amount of ejecta - fragments ejected from the surface - revealing crucial information to improve the effectiveness of future asteroid deflection missions.

The first study was conducted by a team of researchers from the Department of Aerospace Science and Technology at the Politecnico di Milano, lead by Professor Fabio Ferrari and including Paolo Panicucci and Carmine Giordano, in collaboration with the Georgia Institute of Technology. The second study, coordinated by Professor Masatoshi Hirabayashi of Georgia Tech, included contributions from Ferrari himself.

“We used Hubble Space Telescope’s images and numerical simulations to quantify a viable mechanism of the ejecta evolution and successfully estimated ejected particles’ mass, velocity, and size” professor Ferrari explained “We also found complex interactions of such particles with the asteroid system and solar radiation pressure, i.e., sunlight pushing ejecta particles. Understanding these processes is crucial to support effective design of future actions for planetary defense purposes.”

The asteroid’s shape can make a significant difference in its ejecta trajectory, according to the second study from Georgia Tech. Professor Masatoshi Hirabayashi study highlights a surprising finding: it identified the impact scale and the asteroid’s rounded surface lowered the asteroid push by 56% compared to when Dimorphos was tested as an entirely flat wall. Thus, sending a large impactor does not mean a big push.

“If the impact is large, more ejecta fly out of the surface but are more affected by surface tilts. This process makes the ejecta deviate from the ideal direction, reducing the asteroid push.” professor Hirabayashi explained “Sending multiple smaller impactors not only results in a higher asteroid push but also potentially saves operational cost and increases tactical flexibility for deflection.”

Ferrari agrees with this concept, as his study analyzed the evolution of the ejecta, contributing to clarifying their role in asteroid deflection: "Understanding the impact processes and their consequences is crucial to understand the properties of asteroids, their natural evolution and fate, and ultimately, to design mitigation actions for planetary defense purposes.”

The studies

Ferrari, F., Panicucci, P., Merisio, G. et al. Morphology of ejecta features from the impact on asteroid Dimorphos. Nat Commun 16, 1601 (2025). https://doi.org/10.1038/s41467-025-56551-0

Hirabayashi, M., Raducan, S.D., Sunshine, J.M. et al. Elliptical ejecta of asteroid Dimorphos is due to its surface curvature. Nat Commun 16, 1602 (2025). https://doi.org/10.1038/s41467-025-56010-w

Journal

Nature Communications

DOI

10.1038/s41467-025-56551-0

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Morphology of ejecta features from the impact on asteroid Dimorphos

Article Publication Date

19-Feb-2025

Livestock grazing influences insect populations in the Himalayas

Indian Institute of Science (IISc)

image:
The authors during fieldwork in the Spiti region
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Credit: Jalmesh Karapurkar

Domestic grazers are increasingly replacing wild herbivores in ecosystems around the world, leading to insidious changes in soil characteristics and vegetation patterns. A long-term study carried out in the Spiti valley of the Himalayas shows that this replacement can drastically influence the numbers of ground-dwelling arthropods like spiders, as well as that of ticks and mites that can spread vector-borne diseases.

The study found that areas grazed by livestock had greatly reduced spider populations, and larger numbers of grasshoppers and disease carriers like ticks and mites.

“Spiders are predators; their ecological roles are similar to wolves, lions, and tigers. A low abundance of spiders can release grasshoppers from predator control, and lead to many downstream changes in an ecosystem. Together, these effects alter material and energy flow,” says Sumanta Bagchi, Associate Professor at the Centre for Ecological Sciences (CES), Indian Institute of Science (IISc) and corresponding author of the study published in Ecological Applications.

Bagchi and his team have been studying the effects of replacing wild herbivores like the yak and ibex with livestock like cattle and sheep in the Spiti valley for more than 15 years. “Wild herbivores were once ubiquitous across the Earth. Now, they are restricted to a few parks and reserves. Everywhere else, domesticated animals are now dominant,” Bagchi adds.

For the current study, the team tracked the presence of more than 25,000 arthropods spanning 88 different taxa, including spiders, ticks, mites, bees, wasps and grasshoppers, in fenced plots grazed separately by domestic and wild herbivores. They also analysed vegetation biomass and soil conditions like moisture and pH.

“Vegetation and soil biotic and abiotic variables are intertwined in complex ways that we are still unravelling. Arthropods heavily depend on them for food and home, an association developed over centuries with native grazers in the ecosystem,” says Shamik Roy, former PhD student at CES and co-first author. Replacing native grazers with livestock can disrupt this association.

The team found that some arthropod numbers – specifically that of spiders, ticks and mites – were strongly linked to which animal was grazing on the land. While spider numbers dropped under livestock grazing, tick and mite populations drastically increased. Although what exactly is causing the spider numbers to drop is not fully clear, the researchers suggest that it could be because of reduced food sources for spiders and changes in plant types in the area.

“One of the most surprising observations was the massive difference in tick and mite abundance between native grazers and livestock,” says Pronoy Baidya, former PhD student at CES and co-first author. More than 80% of cattle around the world are estimated to harbour ticks that pose a threat to both animal and human health, according to the authors. “This is a major concern for zoonotic diseases and One Health,” Baidya adds.

To counter the consequences of these changes in arthropod numbers, the researchers suggest that steps need to be taken towards “rewilding” native herbivores, and improved surveillance of vector-borne disease risks in areas where animals and humans coexist. The findings also underscore the need for effective conservation policies in areas where large-scale grazing by livestock is carried out.

“Currently, most of the commons are rather mismanaged, allowing people from villages to unsustainably utilise these commons for their livelihoods, and in the process denying the local herbivores their grazing areas,” says Baidya. “Our study will hopefully be an example which may nudge governments to take serious steps for freeing up the commons first and then starting proper ecological restoration of these lands.”

Journal

Ecological Applications

DOI

10.1002/eap.3091

Article Title

Replacing native grazers with livestock influences arthropods to have implications for ecosystem functions and disease

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Thursday, February 20, 2025

The inner ear of Neanderthals reveals clues about their enigmatic origin

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DOI

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Describing previously unknown aspects of Copper Age ceremonial clothing

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DOI

Article Title

Scientists call for efforts to protect habitats of critically endangered shark species

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New ACS study shows cancer mortality rates among Black people declining, but remain higher than other racial and ethnic groups

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Politecnico di Milano and Georgia Tech unveil new scenarios for asteroid deflection

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Livestock grazing influences insect populations in the Himalayas

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