180 million-year-old fossilized fern nearly identical to modern relative

Mar 21, 2014 by Bob Yirka report
This is a collage fern. Credit: Vivi Vajda

(Phys.org) —A trio of researchers in Sweden has unearthed a fossilized fern that has been dated to 180 million years ago, that remarkably, is in near pristine condition. Benjamin Bomfleur and Stephen McLoughlin, of the Swedish Museum of Natural History and Vivi Vajda of Lund University, report in their paper published in the journal Science that they discovered the fossil in a bed of volcanic rock near Korsaröd in Sweden, and found it so well preserved that microscopic analysis revealed that they could make out its DNA structure.

The calcified stem of a royal dating back to the early Jurassic period was apparently preserved by mineral precipitation from hydrothermal brines as they rapidly crystalized, trapping the fern, which was clearly alive at the time, encasing it in an airtight environment. Although very small (just 5.8 x 4.1 cm) the fossil was so well preserved that the researchers were still able to make out cell cytoplasm, nuclei and even chromosomes.

Curious, the team measured the sub-cellular parts of the and compared them to those of a modern relative, the cinnamon fern (Osmundastrum cinnamomeum), which has already earned the title of a "living fossil" due to prior research that revealed its origins could be dated back to 75 million years ago. In so doing they discovered that the number of chromosomes and indeed the DNA content itself was a very close match—so close that the team dubbed them a "paramount example of evolutionary stasis." Remarkably, the plant hasn't changed much at all over a period of 180 million years. When it lived, it likely looked much like the bright green cinnamon fern (though they turn to cinnamon color later in life) of today, growing to a height of one to five feet with spreading fronds reaching six to eight inches. The team suggests the specimen provides exceptional insight into how life can evolve over geologic time.

Unique chromosomes preserved in Swedish fossil
This is a fern fossil. Credit: Benjamin Bomfleur

Finding a plant in such pristine condition is rare, of course, as the researchers note, ferns are part of a group of some of the oldest types of plant families on the planet, going back approximately 360 million years.

Explore further: Parental care of the young from 450 million years ago

More information: Fossilized Nuclei and Chromosomes Reveal 180 Million Years of Genomic Stasis in Royal Ferns, Science 21 March 2014: Vol. 343 no. 6177 pp. 1376-1377 DOI: 10.1126/science.1249884

ABSTRACT
Rapidly permineralized fossils can provide exceptional insights into the evolution of life over geological time. Here, we present an exquisitely preserved, calcified stem of a royal fern (Osmundaceae) from Early Jurassic lahar deposits of Sweden in which authigenic mineral precipitation from hydrothermal brines occurred so rapidly that it preserved cytoplasm, cytosol granules, nuclei, and even chromosomes in various stages of cell division. Morphometric parameters of interphase nuclei match those of extant Osmundaceae, indicating that the genome size of these reputed "living fossils" has remained unchanged over at least 180 million years—a paramount example of evolutionary stasis.

Press release

add to favorites email to friend print save as pdf

Related Stories

Jurassic insect that mimicked ginkgo leaves discovered

Nov 28, 2012

(Phys.org)—Researchers working in China have discovered an insect that lived 165 million years ago that they believe used its wings to mimic the leaves of an ancient ginkgo tree. The fossil finding, the ...

Ash fall preserved 'nursery' of earliest animals

Jun 29, 2012

(Phys.org) -- A volcanic eruption around 579 million years ago buried a 'nursery' of the earliest-known animals under a Pompeii-like deluge of ash, preserving them as fossils in rocks in Newfoundland, new ...

Recommended for you

Ancient clay seals may shed light on biblical era

12 hours ago

Impressions from ancient clay seals found at a small site in Israel east of Gaza are signs of government in an area thought to be entirely rural during the 10th century B.C., says Mississippi State University archaeologist ...

Digging up the 'Spanish Vikings'

Dec 19, 2014

The fearsome reputation of the Vikings has made them the subject of countless exhibitions, books and films - however, surprisingly little is known about their more southerly exploits in Spain.

Short-necked Triassic marine reptile discovered in China

Dec 17, 2014

A new species of short-necked marine reptile from the Triassic period has been discovered in China, according to a study published December 17, 2014 in the open-access journal PLOS ONE by Xiao-hong Chen f ...

Gothic cathedrals blend iron and stone

Dec 17, 2014

Using radiocarbon dating on metal found in Gothic cathedrals, an interdisciplinary team has shown, for the first time through absolute dating, that iron was used to reinforce stone from the construction phase. ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

space music
not rated yet Mar 22, 2014
if it's basically unchanged, where's the evolution?.........
Diogenes Tha Dogg
not rated yet Mar 23, 2014
if it's basically unchanged, where's the evolution?.........


If it ain't broke, don't fix it. - Nature

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.