The Fossil Files

How and when did mammoths go extinct? This week we take a look at two bizarre mammoth related "fossil fails". The first is some unexpected results from from the "adopt-a-mammoth" scheme, a fascinating citizen science project trying to find the youngest mammoth fossil to date their extinction. In the second, we take some time to consider the most bizarre hypothesis of mammoth extinction yet: did they sneeze themselves to death as a result of horrible allergies and then get "snuffed out"? Get your skepticism at the ready. The papers we discuss this week are "Adopted mammoths from Alaska turn out to be a whale's tale" by Matthew Wooller and colleagues published in the Journal of Quaternary Science in December 2025 https://doi.org/10.1002/jqs.70040 and "Sense of smell reduction as factor for mammoth's and other mammals extinction" by Gleb Zilberstein and colleagues published in Earth History and Biodiversity in September 2024 https://doi.org/10.1016/j.hisbio.2024.100008. Relevant past episodes of The Fossil Files are #10 "Fossil Fails: A Precambrian beehive and dinosaurs on the moon" and #3 "Is de-extinction a scam?". Wide screen art by James Havens.

What (and when) is an animal? They are thought to have first arrived about 500 million years ago and immediately underwent an explosive diversifcation at the beginning of the Cambrian. When and how this important event took place has always been hard evolutionary problem to solve: fossils with the necessary preservation of soft-tissues are rare and limited. Two finds from China blow open new windows into this episode. The first is a new site from just before the Cambrian. It yields all sorts of typical Ediacaran weirdos, but preserved in a way that we don't usually get to see them. This not only sheds new light on what was going on before the Cambrian, but also means we can begin to look at the origin of animals in a new way. The second is a new site from 27 million years after Cambrian began. The quality and diversity of the new fossil finds is massive, so much so that it could be considered a new "Burgess Shale", the archetypal and famous Cambrian deposit with exceptional preservation. In a final after-thought, we take a look at sponges and their evolutionary relationships. A new phylogeny helps us to understand why we have such a limited fossil record of early animals: they were likely completely squishy and devoid of a skeleton. Together a more complete picture of our distant animal origins is emerging and how palaeontology can help us, even through the limited windows that we have. The first paper is "The terminal Ediacaran Tongshan Lagerstätte from South China" by Jin-bo Hou and colleagues published in Nature Ecology and Evolution in November 2025. https://doi.org/10.1038/s41467-025-65176-2 The second paper is "A Cambrian soft-bodied biota after the first Phanerozoic mass extinction" by Han Zeng and colleagues published in Nature in Janaury 2026 https://doi.org/10.1038/s41586-025-10030-0 The final paper is "Independent origins of spicules reconcile paleontological and molecular evidence of sponge evolutionary history" by Maria Eleonora Rossi and colleagues published in Science Advances in January 2026 DOI: 10.1126/sciadv.adx1754 Wide screen art by Dinghua Yang.

Life nearly died 252 million years ago in a mass extinction at the end of the Permian. It was long thought that it took 10s of millions of years into the Triassic for life to recover and get back to a 'new normal'. That was until a new and very muddy fossil site from the high Arctic revealed a staggering diversity of predators and tetrapods in the earliest Triassic seas. This week we take a look at the new findings and its implications for life's ability to recover from major extinctions. This week's paper is "Earliest oceanic tetrapod ecosystem reveals rapid complexification of Triassic marine communities" by Aubrey Roberts, published in Science in November 2025 DOI: 10.1126/science.adx739 An accessible summary can be found here. You can see lots of nice pictures and get some extra context from some slides by Jørn Hurum here Wide screen art by Robert Back.

Having large body sizes conferred all sorts of advantages on dinosaurs, but it potentially made breeding a bit complicated. This week we take a look at some weird pathologies in fossil hadrosaurs (duck billed dinosaurs and friends) and what they might tell us about their amourous habits - do broken backs provide evidence of rough housing in the bedroom? This week's paper is "Deciphering causes and behaviors: A recurrent pattern of tail injuries in hadrosaurid dinosaurs" by Filippo Bertozzo and colleagues, published in IScience November 2025 https://doi.org/10.1016/j.isci.2025.113739 The widescreen artwork is by Troco.

New fossil discoveries keep coming thick and fast, but we managed to sit down with the researchers as they present them. In this episode Susie and Rob catch up (in person!) on their second day in Birmingham and talk to the researchers tackling important transitions in vertebrate evolution: the transitions of moving onto land, into the sea, into the air. This includes Emily Hillan of University of Chicago and her discovery of a new specimen of the walking fish (?) Tiktaalik, Dave Hone of Queen Mary University London on his new research on pterosaurs and spinosaurs, Dean Lomax about his new research on ichthyosaurs and his latest book, and Luke Muscutt of Imperial on his swimming plesiosaur robot.

A newly discovered fossil from the Cretaceous of Mongolia tells us an interesting story about the purported head butting behaviour of dinosaurs. Pachycephalosaurs are famous for their thick domed heads but it has been disputed how or when this evolved. The beautifully preserved Zavacephale rinpoche has a well preserved skull and dome but also loads of details of the body and tail as well. What is suprising is that this individual is much smaller, and occurs much earlier, than other pachycephalosaurs. We take a look at this new fossil and what this means for interpreting the evolution of dinosaur behaviour. This week's paper is "A domed pachycephalosaur from the early Cretaceous of Mongolia" by Tsogtbaatar Chinzorig and colleagues from Mongolia and North Carolina, published in Nature in September 2025. https://doi.org/10.1038/s41586-025-09213-6 Wide screen palaeoart by Masaya Hattori.

Discovery of the smallest ever dinosaur acheived quite a splash when it was publised on the front cover of Nature in 2020. The new critter, Oculodentavis, was the size of a hummingbird and reconstructed as close to Archaeopteryx on the lineage to birds. In this episode, Susie and Rob take a look at how this story quickly started to unravel as it turned out Oculodentavis might been something else altogether. This how episode also shed some light on a dark underbelly of an ethical problem for palaeontologists - what if your fossils are coming from a war zone and potentially funding ethic violence? The main paper discussed this week is by Lida Xing and Jingmai O'Connor and colleagues "Hummingbird-sized dinosaur from the Cretaceous period of Myanmar" published in Nature in 2020, now retracted (https://doi.org/10.1038/s41586-020-2068-4). A brief accessible summary of what happened afterwards can be found here by Krister Smith in Current Biology "It's a bird, it's a plane, it's Oculudentavis!" (https://doi.org/10.1016/j.cub.2021.06.017). A summary of the situation with Myanmar amber fossils including discussion of the paper by Emma Dunne and colleagues can be found in Science "Violent conflict in Myanmar linked to boom in fossil amber research, study claims" by Rodrigo Pérez Ortega (doi:10.1126/science.adf0973) Wide screen palaeoart by Stephanie Abramowicz.

Perhaps the weirdest dinosaur ever has just been described in Nature, by The Fossil Files' own Susie Maidment. In a worldwide EXCLUSIVE*, Susie gives as the unvarnshed truth about how this spikey Jurassic weirdo came to be found, what makes it different, and peek under the hood as to how palaeontological research like this is conducted. The story weaves in the local and scientific communities in Morroco, funding crises, a global pandemic, dodgy fossil collectors, international law, and a lot of hard work. The paper is "Extreme armour in the world's oldest ankylosaur" by Susannah Maidment and colleagues, published in Nature August 27th, 2025. https://doi.org/10.1038/s41586-025-09453-6 *Not exclusive Widescreen artwork: Matthew Dempsey

Squid are a really important part of marine ecosystems, but their fossil record is close to non-existent - their squishy bodies are just really unlikely to be fossilised. In this short bonus episode we take a new look at the squid fossil record. 'Digital fossil mining' reveals a massive diversity of squid in Creataceous oceans. How did the scientists do it and what does this mean? The paper is "Origin and radiation of squids revealed by digital fossil-mining" by Shin Ikegami and colleagues of Hokkaido University, Japan. https://doi.org/10.1126/science.adu6248

Pterosaurs dominated Mesozoic skies but it has always been a mystery where these flying reptiles came from. This week Susie and Rob discuss Pterosaur controveries and a cool new study that attempts to solve the problem of where and how they originated. How can you do this? By looking at the climate and locations of where pterosaurs lived and their closest relatives - the weird looking lagerpetids -, we can make predictions about how pterosaurs lived, thrived, and died. And maybe even where we should be looking for them... Figure 4 from paper shows the authors predictions where in the Triassic world would have the right climate for Pterosaurs to live (left column) and Lagerpetids to live (right column). The paper is "Climate drivers and palaeobiogeography of lagerpetids and early pterosaurs" published by Davide Foffa and colleauges in Nature Ecology and Evolution, June 2025. https://doi.org/10.1038/s41559-025-02767-8 Widescreen artwork: Gabriel Ugueto

Our evolutionary timeline just leapt back an additional 40 million years into the past. Some new fossil trackways from the early Carboniferous of Australia have been interpreted as the first bone-fide "amniotes". This is the group of egg laying vertebrates which we belong to along, with all the other mammals, birds, and reptiles. These fossils are much earlier than previously thought possible and potentially turns our understanding of this event on its head. We take a look at these fossils and the implications, in particular that there could be loads of missing things out there yet to be found, including our own ancestors and distant relatives. Figure from the study showing the fossil footprints slab, with details of fingers/toes and claws scrapping along the surface, and fossil rain drops. The paper is "Earliest amniote tracks recalibrate the timeline of tetrapod evolution" by John Long and colleagues, published in Nature in May 2025. https://doi.org/10.1038/s41586-025-08884-5 Widescreen artwork: Marcin Ambrozik..

How did dinosaurs rise to supremacy? This difficult question is given "fresh" insights from new data from a motherload of fossils from Poland. Over 500 bromalites - fossil vomit, gut contents or poo - were analysed with new technology allowing reconstruction of how diets and ecosystems changed over this crucial time. We take a look at some of these fossils and interpretations and speculate about how to experimentally test these smelly findings. Figure 2: A selection of fossils found inside the bromalites (gut contents, vomit, and poos) from the paper. a - fish scales in a lungfish bromalite, b - teeth and bones with bite marks including a dicyndont in an archosaur bromalite , c - crocodylomorph bones in a theropod bromalite, d- several whole beetles in an early dinosaur bromalite, f - plant fossils including ferns from inside bromalites, g - fish inside a phytosaur coprolite, h and i - fragmented plants. Figure 3: The authors interpretations of the foodwebs and ecosystems changing during the Triassic. The paper is "Digestive contents and food webs record the advent of dinosaur supremacy" by Martin Qvarnström from Uppala University and colleagues from Poland, published in Nature.. https://doi.org/10.1038/s41586-024-08265-4

In "The Fossil Files", a pair of palaeontologists delve into the latest discoveries from the world of palaeontology and seek to bring fossils to back to life. Each episode, Susie and Rob will discuss an interesting new research paper ranging from topics of what dinosaurs ate, how plesiosaurs swam, where we came from, and the science of de-extinction. Whilst doing so, we peek under the hood of how the science of palaeontology is done and how research gets to see the light of day. It is accessible to all those interested in palaeontology whether that is students, researchers themselves, or simply the fossil-curious - we laugh as we learn, and hope you will too. In this trailer we introduce "The Fossil Files" explaining a bit about our approach and our background. In our day jobs, Susannah Maidment (Natural History of London) conducts museum work and fieldwork to reconstruct dinosaur anatomy, evolution and ecology and Robert Sansom (University of Manchester) undertakes fossil and lab analyses to reconstruct early vertebrates, evolutionary relationships and how fossils are formed.