While fossilized plants are dime a dozen, scientists rarely get the chance to examine intact plant cells from almost 200 million years ago. That's exactly what scientists are fussing over after researchers rediscovered a remarkably well-preserved fossilized fern in Sweden.
The 180-million-year-old fossilized fern was rediscovered by researchers from the Swedish Museum of Natural History and the Lund University stored in the one of the museum's collections. The fossil was found by Gustav Andersson in the Skåne country in the southern part of Sweden back in the 1960s. Andersson, a farmer, then donated the fossil to the Swedish Museum of Natural History where it was stored for five decades until it was found by the researchers.
Unlike most plant fossils from the Jurassic era, this particular fern was very well-preserved. Upon closer inspection scientists found that some of the fern's cells still had their individual chromosomes and cell nuclei intact. The fossil's well-preserved state was likely due to a sudden volcanic eruption that quickly buried the fern in volcanic materials.
"The preservation happened so quickly that some cells have even been preserved during different stages of cell division", said Lund University professor of geology Vivi Vajda.
The Swedish researchers published their study in the online journal Science. Back when the fern was still alive, Sweden was a tropical land that had numerous volcanoes. Most of the fauna living in the area were dinosaurs and the flora was dominated by Jurassic ferns.
The researchers who were studying the fossilized fern used a variety of techniques including geochemical analysis, X-ray scans and microscopes to unlock the secrets of the fossil. Due to the speed at which it was buried, all of the plant's cellular components where undamaged, which makes the fossil a very rare find.
"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", Vivi Vajda added.
Vajda and her colleagues found that the fern belonged to a family of plants called Osmundaceae. The fossilized fern is one of the ancestors of Royal Ferns, a very common type of plant in Sweden today. Vajda also said that modern Royal Ferns are very similar both in structure and appearance to their Jurassic ancestors. After studying the fossil, the researchers found that this type of fern did not experience any major evolutionary changes even after almost 200 million years.
"Royal Ferns look essentially the same now as they did during the Jurassic Period and are, therefore, an excellent example of what we call a living fossil", said Vivi Vajda.
