After studying the earth for thousands of years, you might have thought we had uncovered all of the ancient artefacts from the beginning of life. But you would be mistaken, as researchers in China have just discovered a treasure chest of fossils dating back to half a billion years ago.
Photo credit: D. FU ET AL/SCIENCE 2019
Not tens, not hundreds but thousands of fossils have just been unearthed from rocks on the bank of the Danshui river in Southern China. These fossils were once organisms, including jellyfish, anemones, worms and arthropods, which were caught in an ancient underwater mudslide. But, paradoxically, what destroyed these creatures also preserved them. And they have been preserved for approximately 500 million years.
The phrase ‘treasure chest’ is also very appropriate as they fossils have been so well preserved that palaeontologists have uncovered an abundance of new information. With the soft tissues of the creatures’ bodies still visible, including muscles, guts, eyes and gills, the 4,351 fossils excavated so far have already become 53 new species.
These fossils, of both existing and new species, date back to 518 million years ago. At this time, life on planet earth had an explosion in diversity, leading to the beginning of animal life. Many creatures went extinct as natural selection took its toll, but many progressed on through time and led to the wildlife we know today. This monumental explosion is known scientifically as the Cambrian Explosion.
Until today, the most prominent fossils relating to the Cambrian Explosion were from a rock in Canada called the Burgess Shale, which is 508 million years old, and in the 518 million-year-old Chengjiang formation (also in China). However, the new fossils just uncovered on the banks of the Danshui River are fundamental in painting a more comprehensive picture of the Cambrian Explosion and the beautifully intricate ecosystems which developed at this time.