The hunt for the first-ever animals, with Emily Mitchell

The hunt for the first-ever animals, with Emily Mitchell

Where, when, and how did the animals first appear? The fossil record holds some tantalising insights from well-preserved sites in Canada, Australia, Russia (and Leicester). This week we are joined by Dr Emily Mitchell of the University of Cambridge to discuss how to find these fascinating Ediacaran fossils, what they mean, and how they evolved. Did they move? Were they left-handed? Did they have sex? Where are they hiding? This is a story that includes lasers, school children, lichens, and bees. The papers discussed this week are "Earliest evidence of behavioural handedness in the Ediacaran motile bilaterian Spriggina floundersi" by Scott Evans and colleagues published in Science Reports in July 2026 https://doi.org/10.1038/s41598-026-53857-x [https://doi.org/10.1038/s41598-026-53857-x], and "Discovery of White Sea assemblage fossils from Laurentia" by Scott Evans and colleagues published in Science Advances in May 2026 https://doi.org/10.1126/sciadv.aed9916 [https://doi.org/10.1126/sciadv.aed9916] We also continue of our discussion of last episodes's paper, "The influence of reproductive mode on resource competition and diversity patterns in Ediacaran early animal communities" by Emily Mitchell and Andrea Manica published in Nature Ecology and Evolution in June 2026 https://doi.org/10.1038/s41559-026-03094-2 [https://doi.org/10.1038/s41559-026-03094-2]

Did a lack of sex hold back the evolution of the first animals?

The first animals turned up in the Ediacaran as simple frond-like organisms that didn't do much of anything. Why was this Pre-Cambrian 'Avalonian biota' so static and boring for 12-20 million years before animals started diversifying, moving and becoming more complex? This week we look at a new paper that reconstructs the ecology of the early Avalonian biota, in particular their sexual and and asexual reproductions strategies. To try and figure out what kind of sex these organisms were (or weren't) having, we need to do turn to some interesting maths based on their locations of the fossil surface. This unlocks all sorts of interesting evolutionary dynamics, potentially explaining how animals started to diversify after increasing sexual reproduction and competition in an increasingly dynamic and changeable environment. Life needed chaos! (and sex). This week's paper is "The influence of reproductive mode on resource competition and diversity patterns in Ediacaran early animal communities" by Emily Mitchell and Andrea Manica published in Nature Ecology and Evolution, published June 2026 https://doi.org/10.1038/s41559-026-03094-2 [https://doi.org/10.1038/s41559-026-03094-2] We also mention another paper by Scott Evans (https://www.science.org/doi/10.1126/sciadv.aed9916) [https://www.science.org/doi/10.1126/sciadv.aed9916)] and the story of the discovery of the Ediacaran fossils in Charnwood fossil https://en.wikipedia.org/wiki/Tina_Negus [https://en.wikipedia.org/wiki/Tina_Negus] Wide screen art by Hugo Salais.

Why did T. rex have such small arms? Revealed

Tyrannosaurus rex is perhaps the most famous dinosaur and maybe even the most famous fossil animal. It has long been a source of curiosity as to why is has such small arms though. What could the possible function be? This week we take a look at a new paper has taken a quantitative approach to this age long-thorny problem to investigate the evolutionary changes that might have led to such unusual anatomy. Indeed it happened not just one, but five times in the theropods. Let's find out why and how! This week's paper is "Drivers and mechanisms of convergent forelimb reduction in non-avian theropod dinosaurs" by Charlie Scherer and colleagues published in Proceedings of the Royal Society in May 2026. https://doi.org/10.1098/rspb.2026.0528 [https://doi.org/10.1098/rspb.2026.0528] Wide screen art by Arvalis/Saurian.

Digging for dinosaurs and the battle against poaching: Susie reports from the field [Preview]

Digging up dinosaur fossils is a complicated and unpredictable business. But how does it feel to be one of the scientists on the ground doing the exploring? What can you do when you are in a race to find dinosaur fossils before they are extracted and lost to the black market? In this episode Susie is in the field in Morocco to report the trials and tribulations of the team's dino hunting seasons. She takes us on a journey from exciting new dinosaur finds, disappointing setbacks when their quarry was raided, and their work with the local and national authorities to get the site protected for future generations. This is a preview of one of our bonus episode, the full version of which is available on our patreon for subscribers https://www.patreon.com/cw/FossilFiles [https://www.patreon.com/cw/FossilFiles] In this episode we hear from the team which includes Ahmed Oussou and Kawtar Ech-Charay of Sidi Mohamed Ben Abdellah University Fez, Richard Butler from the University of Birmingham, and Simon Wills and Pim Kaskes from the Natural History Museum London. You can find out more about Susie's work in episode 9, "The Spicomellus special".

The Fossil Files is one year old: The best bits so far

The Fossil Files is one year old! Thank you everbody for your support! To mark the occasion, Susie and Rob take a look back at the last year and put together some of their favourite moments to highlight the best of The Fossil Files (so far) The episodes covered are: Episode 10. Fossil Fails: A Precambrian beehive and dinosaurs on the moon (September) Episode 3. Is de-extinction a scam? (July) Episode 6. Where did Pterosaurs come from? (August) Episode 12. Cretaceous zombie ants (October) Episode 9. The Spicomellis special (September) Episode 5. Were Neanderthals the first fossil collectors? (July) Episode 19. Dinosaurs were doing fine (before the asteroid), with Steve Brusatte (December) Episode 17. AI & the future of palaeontology (December) Episode 2. Dinosaur poos from Poland (June) Episode 20. Back-breaking and baby making, the disturbing bedroom habits of hadrosaurs (January) Episode 28. How to get a Species of Human Named after you (March) Episode 32. Were giant super intelligent octopuses the top predators of the Cretaceous? (May)