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

The origin of our own group, the vertebrates, has received quite the shake up. One of the important fossil players has been found to be an invertebrate imposter, and this completely changes our understanding of this evolutionary episode. We take a look at why and when, and how this boils to down to a interesting question all about teeth. Did our entire skeleton come from teeth on the outside of our bodies, even before jaws existed? Is this why we now get tooth ache? 

The paper is "The origin of vertebrate teeth and evolution of sensory exoskeletons" by Yara Haridy and colleagues, published in Nature in May 2025. https://doi.org/10.1038/s41586-025-08944-w

Wide screen art: Brian Engh. 

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

Why do we collect fossils and who were the first fossil collectors? Cretaceious fossils have been found in a cave in Northern Spain alongside the Neanderthals that were living there 46,000 years ago. Were Neanderthals collecting fossils and if so why? This week Susie and Rob examine those claims and discuss fossil collecting and the recent surge in private trade in dinosaur fossils. 

Because we are children, we also giggle at possibly one of the earliest fossils collected, the Erfoud Manuport as well as the Makapansgat pebble. 

The paper is "Were Neanderthals the First Collectors? First Evidence Recovered in Level 4 of the Prado Vargas Cave, Cornejo, Burgos and Spain" by Marta Navazo Ruiz and colleagues from the University of Burgos. https://doi.org/10.3390/quat7040049

We also go on to discuss the Stegosaur fossil Apex sold, purchased and loaned to the American Museum of Natural History (AMNH) and the sale of a Ceratosaurus fossil by Utah's Museum of Ancient life.

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..

Can we bring extinct organisms back to life? Colossal Biosciences caused quite the stir earlier this year when claimed they could do just that, and indeed have done with Dire Wolves - an extinct species of candid from North America. What is going on here? We sense check those claims and ask what they did (and did not do) as well as the broader implications of the science (pseudoscience?) of de-extinction. 

The front cover of "Time" magazine - no ambiguity here about what they are saying.

Here is the phylogeny (evolutionary tree) from the paper. Dire wolves have a long branch arising from a point between Jackal/Dog/Dhole/Wolf on the one side and Bush Dog/Maned wolf on the other side.

There was a lot of press about this work, but the paper it comes from is a pre-print "On the ancestry and evolution of the extinct dire wolf" uploaded to BioRxiv in April 2025 by Gregory Gedman and Beth Shapiro of Colossal Biosciences, and colleagues, including George R. R. Martin (!). 

Update: the 3 individuals are not technically clones but genetically manipulated grey wolves

https://doi.org/10.1101/2025.04.09.647074

Widescreen artwork: Colossal Biosciences

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

For our first paper, we look at some exceptional preservation of soft tissue in Jurassic plesiosaur (large marine reptiles). Detailed preservation of soft tissues to the sub-cellular level is very rare in the fossil record. We discuss this specific example from Germany (which we name Nigel) and the types of analyses that the authors did of its skin and tissues. This new data helps us reconstruct how plesiosaurs may have lived and moved. Or does it?

In this figure from the paper we can see the whole fossil of Nigel (A), a close up of the preserved skin (B and C), and a cross section of the sub-cellular detail from the fossil skin (D and E) compared with skin cells from a modern turtle (F). 

The paper is "Skin, scales, and cells in a Jurassic plesiosaur" published in Current Biology in 2025 by Miguel Marx of Lund Univertsity Sweden, and colleages. https://doi.org/10.1016/j.cub.2025.01.001

Widescreen artwork: Joshua Knüppe

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.