The Fossil Files

24. How and when did animals first appear? Extraordinary new fossils from China


Listen Later

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.

...more
View all episodesView all episodes
Download on the App Store

The Fossil FilesBy Robert Sansom and Susannah Maidment

  • 5
  • 5
  • 5
  • 5
  • 5

5

2 ratings


More shows like The Fossil Files

View all
In Our Time by BBC Radio 4

In Our Time

5,555 Listeners

Page 94: The Private Eye Podcast by Page 94: The Private Eye Podcast

Page 94: The Private Eye Podcast

422 Listeners

The Common Descent Podcast by Common Descent

The Common Descent Podcast

738 Listeners

Terrible Lizards by Iszi Lawrence and David Hone

Terrible Lizards

186 Listeners

The News Agents by Global

The News Agents

1,253 Listeners