The Fossil Files

Dinosaurs were massive. No cap. They spread all over the world, but how did they cross oceans? In this episode we ask the question: how far could a dinosaur swim? This isn't just an esoteric question, but one that has a big impact on how we try to reconstruct palaeobiogeography of the Mesozoic and how diversification happens. To do so we look at some new fossil finds from Spain and some weird maths based on rare footage of ostriches swimming and how much fat was on a sauropod. 
This week's papers are 
"Intercontinental evidence of the iconic genus Diplodocus Marsh, 1878 (Dinosauria, Sauropoda)" by Sergio Sánchez-Fenollosa and colleagues published in Journal of Vertebrate Paleontology in Jan 2026 http://dx.doi.org/10.1080/02724634.2026.2718423 and 
"ENHYDROSS: A New Mechanistic Model Supports the Trans-Oceanic Dispersal Capability of Terrestrial Vertebrates" by Alexandros Pantelides and colleagues published in Ecology and Evolution in March 2026 https://doi.org/10.1002/ece3.73280 
Wide screen art by Sante Mazzei

How and when did mammals transition from laying eggs to live birth? The fossil record doesn't typically preserve soft tissues like embryos and placentas making this a tough problem. This week we take a look at two new fossil discoveries that begin to answer the question of mammal evolution, and challenge orthodoxy. A cute baby dicynodont fossil from the Triassic of South Africa is the first mammal to be captured 'in ovo' i.e. inside its egg. Secondly, we discuss a new fossil cynodont from the Triassic of Argentina that might have recorded its growth and birth in its bone histology. Using this we begin to piece together our own evolutionary history and estimate when placental mammals 'got cracking'. Along we way we ask if viviparity evolved twice and whether teenagers can be trusted to go to the shops to get eggs.
The papers discussed this week are "The first non-mammalian synapsid embryo from the Triassic of South Africa" by Julien Benoit and colleagues published in PLoS One in April 2026 https://doi.org/10.1371/journal.pone.0345016 and "Early origin of viviparity in the mammalian lineage" by Leandro Carlos Gaetano and colleagues published in Frontiers in Mammal Science https://doi.org/10.3389/fmamm.2026.1845319
Palaeoart by Sophie Vrard.

New finds in palaeontology are dependent on people getting out in the field and digging up fossils, but are the next generation of palaeontologists getting to do that? Opportunities for fieldwork and fieldwork training have become more expensive, which means students might not be getting the training they need. What happens next? In this week's bonus episode, Susie and Rob discuss the importance of fieldwork and whether the next generation of palaeontologists are facing 'an extinction of experience'. We focus on the views of students and early career researchers and ponder what happens to palaeontology if we focus on large scale studies of existing data to the exclusion of digging up new stuff. This is a preview of the full episode available to our Patreon members https://www.patreon.com/cw/FossilFiles
The main paper discuss in this episode is "#Yourpalaeolife: Interrogating the Status of Fieldwork Among Early Career Palaeontology Researchers" by Harriett Nuttall published in Ecology and Evolution in July 2026 https://doi.org/10.1002/ece3.74032
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Sounds play such an important ecological role, but palaeontologists have always had to use their imagination when reconstructing the sound of extinct landscapes: Until now! For the first time a team of scientists have reconstructed the sound of a whole palaeo-community. Using fossil insect wings and some technological approaches to modern animals, the team were able to use physics and AI models to reconstruct the acoustic landscape of a Jurassic forest peppered with the calls of insects. Were the animals avoiding predators or just talking to each other? Listen in and find out. 
This week's paper is "Reconstruction of an extinct soundscape reveals ultrasonic communication in the Jurassic" by Jun-Jie Gu, Fernando Montealegre-Zapata and colleagues published in Proceedings of the National Academy of Sciences in August 2026 https://doi.org/10.1073/pnas.2615107123
We also provide some updates from previous episodes:
#5 "Were Neanderthals the first fossil collectors" updated with Roman findings https://doi.org/10.1017/S0068113X26100749
#30 "How can we reconstruct the smell of extinct organisms" smells different using new data from fishes https://doi.org/10.1098/rspb.2025.3277
#25 "A dinosaur covered in porcupine spines & the earliest fossil cloaca" gets a new friend with the discovery of an early mammal cloaca https://doi.org/10.1016/j.isci.2026.116752
And the most controversial of all #4 "Is de-extinction a scam?", well it looks more likely given what got left out when the paper finally came out https://doi.org/10.1016/j.xgen.2026.101306
Widescreen art by Zuo Xiaoran

The origin of turtles has long been a scientific mystery. Not only do they have super weird things going on with their ribs, head, and teeth, but also its unclear if they were more closely related to birds and crocodiles, or snakes and lizards, or something else. This week we take a deep dive into the origin of turtles, terrapins and tortoises, and the process of "turtleization". New data from the important Permian critter Eunotosaurus of South Africa might have now solved that problem of the question: Where did turtles come from?
This weeks's paper is "The phylogenetic origin of turtles" by Xavier Jenkins and colleagues published in Current Biology in June 2026 https://doi.org/10.1016/j.cub.2026.04.070
Wide screen art by Gabriel Ugeuto.