Somewhere around 180 million years ago, during the Jurassic period, the southern Swedish county of Skåne was a tropical paradise populated by dinosaurs and volcanoes.

One sudden volcanic eruption caused a fern to be preserved instantaneously and now researchers from Lund University and the Swedish Museum of Natural History have made a unique discovery; both undestroyed cell nuclei and individual chromosomes have been found in the plant fossil.

The well-preserved fossil has been studied using different microscopic techniques, X-rays and geochemical analysis. The examinations reveal that the plant was preserved instantaneously, before it had started to decompose. It was buried abruptly under a volcanic lava flow. Thanks to the circumstances of the fern's sudden death, the sensitive components of the cells have been preserved. The researchers have found cell nuclei, cell membranes and even individual chromosomes. Such structures are extremely rare finds in fossils 

Fern collage. Credit: Vivi Vajda

"The preservation happened so quickly that some cells have even been preserved during different stages of cell division," said Vivi Vajda, Professor of Geology at Lund University. "This naturally leads us to think that there must be more to discover. It isn't hard to imagine what else could be encapsulated in the lava flows at Korsaröd in Skåne."

Fern fossil. Credit: Photo: Benjamin Bomfleur


By comparing the size of the cell nuclei in the fossilized plant with its living relatives, the researchers have been able to show that the royal ferns have outstanding evolutionary stability.




Publiished in Science. Source: Lund University