(Image: Benjamin Bomfleur)

One hundred and eighty million years ago, this Jurassic fern was minding its own business when it was suddenly engulfed by a lava flow. The plant was almost instantly fossilised, preserving it in incredible detail – right down to its individual chromosomes in various stages of cell division.

This image shows a cross section through the stem of the fossil fern, revealing the central cylinder that connects the roots with the rest of the plant. The photo below shows a close-up of the preserved cell walls and the nucleus containing genetic material.

(Image: Benjamin Bomfleur)


The fossil was discovered in the 1960s by a farmer in Skåne county, southern Sweden. He donated it to the Swedish Museum of Natural History, where it sat in a drawer for more than 40 years until palaeobiologists took a closer look for a study published today in Science.

The fern is very similar to a living species: the cinnamon fern, Osmundastrum cinnamomeum. The similarity of the cinnamon fern to the fossil supports the idea that is a “living fossil” – an example of evolutionary stasis, when organisms appear not to evolve for millions of years.

The fern’s stunning preservation leads many to hope that all sorts of other things might be preserved in the Skåne lava.

Journal reference: Science, DOI: 10.1126/science.1249884