Fossils reveal ‘latitudinal traps’ that increased extinction risk for marine species

University of Oxford

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Infographic describing the study’s findings. Credit: Getty Images, Public Affairs Directorate, University of Oxford.

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Credit: Getty Images, Public Affairs Directorate, University of Oxford.

A new study led by researchers at the University of Oxford has shown that the shape and orientation of coastlines significantly influenced extinction patterns for animals living in the shallow oceans during the last 540 million years. In particular, animals living on convoluted or east-west orientated coastlines (such as those found in the Mediterranean and Gulf of Mexico today) were more likely to go extinct than those living on north-south orientated coastlines.

The findings, published today (15 Jan) in Science, provide new insight towards understanding patterns of biodiversity distribution throughout Earth history to the present day, and highlight which modern species may be more at risk of extinction due to climate change.

The researchers analysed over 300,000 fossils for over 12,000 genera of marine invertebrates, combining these with reconstructions of continental arrangements at different times in the past. This enabled them to run a powerful statistical model to test the hypothesis that the orientation and shape of a coastline influenced a taxon’s chance of extinction.

The model revealed that invertebrates living in environments such as east-west orientated coastlines, islands or inlands seaways, where migration to a different latitude was difficult, or impossible, were consistently more vulnerable to extinction than those which could move more easily in a northwards or southwards direction.

Study co-author Professor Erin Saupe (Department of Earth Sciences, University of Oxford) said: “Generally, coastlines with a north-south orientation better allowed species to migrate during periods of climate change, enabling them to stay within their ideal temperature tolerance range. This reduces their risk of extinction. Conversely, groups that are trapped at one latitude, because they live on an island or an east-west coastline, for example, are unable to escape unsuitable temperatures and are more likely to become extinct as a result.”

The researchers were also able to show that this effect was heightened during mass-extinctions and hyperthermal (extremely warm) periods, and that coastline geometry became even more important for survival during these times.

Lead author Dr Cooper Malanoski (Department of Earth Sciences) said: “This shows how important palaeogeographic context is – it allows taxa to track their preferred conditions during periods of extreme climate change. And palaeogeography could provide one explanation for why some mass extinctions are more severe than others – some continental configurations may make it harder for groups to avoid the extreme climate changes during these events.”

The findings highlight that present-day species in isolated habitats that cannot easily migrate to a different latitude may be especially vulnerable to anthropogenic climate change. This information could be useful when determining conservation priorities and for identifying vulnerable marine populations into the future, especially those humans rely on for ecosystem services.

Professor Saupe added: “This work confirms what many palaeontologists and biologists have suspected for years – that a species' ability to migrate to different latitudes is vital for survival. By examining the fossil record of marine invertebrates restricted to shallow marine environments, we have been able to test this hypothesis with rigorous statistical analyses. An exciting next step is to see if we can observe this effect today.”

The study was conducted in collaboration with the University of California, Berkeley (USA), Stanford University (USA), University of Leeds (UK), and the Smithsonian Tropical Research Institute (Panama).

Notes for editors:

For media enquiries and interview requests, contact Professor Erin Saupe erin.saupe@earth.ox.ac.uk and Dr Cooper Malanoski cooper.malanoski@wolfson.ox.ac.uk.

The study ‘Paleogeography modulates marine extinction risk throughout the Phanerozoic’ will be published in Science at 19:00 GMT / 14:00 ET Thursday 15 January 2026 DOI 10.1126/science.adv2627. More information, including a copy of the paper, can be found online at the Science press package at https://www.eurekalert.org/press/scipak/ or by contacting scipak@aaas.org.

About the University of Oxford

Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the tenth year running, and ​number 3 in the QS World Rankings 2024. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer.

Oxford is world-famous for research and teaching excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research alongside our personalised approach to teaching sparks imaginative and inventive insights and solutions.

Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 300 new companies since 1988. Over a third of these companies have been created in the past five years. The university is a catalyst for prosperity in Oxfordshire and the United Kingdom, contributing around £16.9 billion to the UK economy in 2021/22, and supports more than 90,400 full time jobs.

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Journal

Science

DOI

10.1126/science.adv2627 

Article Title

Paleogeography amplifies marine extinction risk over the Phanerozoic

Article Publication Date

15-Jan-2026

 

Professor Erin Saupe examining fossil invertebrate specimens that lived in past seas. Credit; Charlie Rex.

Collection of invertebrate specimens, showing some of the groups investigated as part of this study. Credit: Charlie Rex.

Collection of invertebrate specimens, showing some of the groups investigated as part of this study. Credit: Charlie Rex.

Infographic describing the study’s findings. Credit: Getty Images, Public Affairs Directorate, University of Oxford.

Professor Erin Saupe examining fossil invertebrate specimens that lived in past seas. Credit: Charlie Rex.

Tiny earthquakes reveal hidden faults under Northern California

University of California - Davis

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The Mendocino Triple Junction is the meeting point of three tectonic plates. Using data from tiny earthquakes, researchers at USGS, UC Davis and CU Boulder propose a new model for this seismic zone. The Pacific plate is dragging the Pioneer fragment under the North American plate as it moves north. At the same time, a fragment of the North American plate has broken off and is being subducted with the Gorda plate. 

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Credit: David Shelly, USGS

By tracking swarms of very small earthquakes, seismologists are getting a new picture of the complex region where the San Andreas fault meets the Cascadia subduction zone, an area that could give rise to devastating major earthquakes. The work, by researchers at the U.S. Geological Survey, the University of California, Davis and the University of Colorado Boulder, is published Jan. 15 in Science.

“If we don’t understand the underlying tectonic processes, it’s hard to predict the seismic hazard,” said coauthor Amanda Thomas, professor of earth and planetary sciences at UC Davis.

Three of the great tectonic plates that make up the Earth’s crust meet at the Mendocino Triple Junction, off the Humboldt County coast. South of the junction, the Pacific plate is moving roughly northwest against the North American plate, forming the San Andreas fault. To the north, the Gorda (or Juan de Fuca) plate is moving northeast to dive under the North American plate and disappear into the Earth’s mantle, a process called subduction.

But whatever is going on at the Mendocino Triple Junction is clearly a lot more complex than three lines on a map. For example, a large (magnitude 7.2) earthquake in 1992 occurred at a much shallower depth than expected.

First author David Shelly of the USGS Geologic Hazards Center in Golden, Colo., compared it to studying an iceberg.

“You can see a bit at the surface, but you have to figure out what is the configuration underneath,” Shelly said.

Shelly, Thomas, Kathryn Materna at CU Boulder and Robert Skoumal at USGS’s Earthquake Science Center at Moffett Field, Calif., used a network of seismometers in the Pacific Northwest to measure very small, “low-frequency” earthquakes occurring where the plates rub against or over each other. These earthquakes are thousands of times less intense than any shaking we could feel at the surface.

They confirmed their model by looking at how the plates respond to tidal forces. The gravitational forces of the Sun and Moon pull on tectonic plates just as they do on the waters of the ocean. When tidal forces align with the direction in which a plate wants to move, you should see more small earthquakes, Thomas said.

Five moving pieces

The new model includes five moving pieces, not just three plates – and two of them are out of sight from the Earth’s surface.

At the southern end of the Cascadia subduction zone, a chunk has broken off the North American plate and is being pulled down with the Gorda plate as it sinks under North America, the team found.  

South of the triple junction, the Pacific plate is dragging a blob of rock called the Pioneer fragment underneath the North American plate as it moves northwards. The fault boundary between the Pioneer fragment and the North American plate is essentially horizontal and not visible from the surface at all.

The Pioneer fragment was originally part of the Farallon plate, an ancient tectonic plate that once ran along the coast of California but is now mostly gone.

The new model explains the shallowness of the 1992 earthquake, because the subducting surface is shallower than previously thought, Materna said.

“It had been assumed that faults follow the leading edge of the subducting slab, but this example deviates from that,” Materna said. “The plate boundary seems not to be where we thought it was.”

The work was supported by a grant from the National Science Foundation.

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Journal

Science

DOI

10.1126/science.aeb2407 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Low-frequency earthquakes track the motion of a captured slab fragment

Article Publication Date

15-Jan-2026

 

Long-term pesticide exposure accelerates aging and shortens lifespan in fish

University of Notre Dame

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University of Notre Dame biologist Jason Rohr

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Credit: Photo by Barbara Johnston/University of Notre Dame

Long-term exposure to low levels of a common agricultural pesticide can accelerate physiological aging and shorten lifespan in fish — a finding from new research led by University of Notre Dame biologist Jason Rohr with potentially far-reaching implications for environmental regulations and human health.

The study, published in Science, shows that chronic exposure to the insecticide chlorpyrifos at concentrations too low to cause immediate toxicity causes fish to age faster at the cellular level.

The research began with field studies in China where collaborators examined thousands of fish collected over several years from lakes with differing levels of pesticide contamination. Rohr and colleagues observed that fish living in contaminated lakes lacked older individuals, while populations in relatively uncontaminated lakes included many older fish. This pattern suggested that fish were not failing to add to their populations, but rather were dying earlier in life.

“When we examined telomere length and deposition of lipofuscin in the livers of the fish, well-established biological markers of aging, we found that fish of the same chronological age were aging faster in the contaminated than clean lakes,” said Rohr, the Ludmilla F., Stephen J. and Robert T. Galla Professor and Chair in the Department of Biology.

Chemical analyses revealed that chlorpyrifos was the only compound found in the fish tissues that was consistently associated with signs of aging. These include shortened telomeres, which act like the plastic caps shoelaces and decrease fraying in chromosomes, and lipofuscin deposition, a build-up of “junk” like old proteins and metals within long-lived cells. However, to determine whether chlorpyrifos was the direct cause, researchers needed to conduct controlled laboratory experiments with concentrations matching those measured in the wild, Rohr said.

In this laboratory experiment, chronic low-dose exposure to chlorpyrifos caused progressive telomere shortening, increased cellular aging and reduced survival, particularly in fish from the contaminated lakes that were already physiologically older.

Graphic from the study published in Science

“Although the laboratory results closely matched the field observations, it was possible that a missed high-dose exposure event in the field, rather than chronic low-dose exposures, caused the reduced lifespan,” said Rohr, who is affiliated with Notre Dame’s Berthiaume Institute for Precision Health, Environmental Change Initiative and Eck Institute for Global Health.

To rule out this driver, Rohr and colleagues conducted another laboratory experiment demonstrating that short-term exposure to much higher doses caused rapid toxicity and death but did not accelerate aging through shortened telomeres and increased lipofuscin. This demonstrated that long-term accumulation of exposure to extremely common low concentrations — not brief high-dose spikes — was responsible for the observed aging, Rohr said.

The loss of older individuals can have serious ecological consequences, as older fish often contribute disproportionately to reproduction, genetic diversity and population stability, Rohr said.

“These findings also raise broader concerns because telomere biology and aging mechanisms are highly conserved across vertebrates, including humans,” Rohr said. Potential future research will explore how widespread the phenomenon may be across species and chemicals.

While the European Union has largely banned chlorpyrifos, it remains in use throughout China, parts of the United States and in many other countries. However, the aging effects observed in this study occurred at concentrations below current U.S. freshwater safety standards, Rohr said.

“Our results challenge the assumption that chemicals are safe if they do not cause immediate harm,” he said. “Low-level exposures can silently accumulate damage over time by accelerating biological aging, highlighting that chemical safety assessments must move beyond short-term toxicity tests to adequately protect environmental and human health.”

The research was funded by the National Science Foundations in both the United States and China, the Illinois-Indiana Sea Grant and the Frontiers Research Foundation.

Journal

Science

DOI

10.1126/science.ady4727 

Article Title

Chronic low-dose exposure to chlorpyrifos reduces lifespan in a wild fish by accelerating aging

Article Publication Date

15-Jan-2026