A newly discovered fossil site in China that dates back 518 million years contains more than 50% previously unknown species, according to a new study. The well-preserved Qingjiang site is helping scientists to fill gaps in the fossil record and provide a clearer picture of some of the earliest animal ecosystems.
The site is unique in that it not only includes well-preserved fossils but soft-bodied organisms as well. Some of the animals include corals, sponges, sea anemones, jellyfish, comb jellies, arthropods and tiny invertebrates called mud dragons, as well as microscopic fossils.
The study published Thursday in the journal Science.
The discovery is comparable to other impressive sites like the Burgess Shale in the Canadian Rocky Mountains, discovered in 1909, Chengjiang in China and Emu Bay Shale in Australia. Burgess dates to 508 million years ago and includes well-preserved fossils, including soft bodies that show evidence of skin, eyes, gut and brains.
The sites are the gold standard for scientists piecing together the Cambrian Explosion about 540 million years ago, when an immensely diverse animal population suddenly appeared over a short time. Researchers have discovered more sites containing great records of the Cambrian Explosion in recent years, like the Qingjiang site.
The researchers who worked on the Qingjiang site believe their discovery may rival some of the other sites because it had the highest relative diversity of species and is ten million years older than Burgess, said Xingliang Zhang in an email, study author and professor at Northwest University’s department of geology.
The diversity of species creates an interesting picture of evolution.
“[This is an] excellent preservation of so many Cambrian creatures,” Zhang said. “Some are weird, some exactly look like what we have today.”
The site was found on the bank of the Danshui River in China’s Hubei Province, which is about 652 miles northeast of the other fossil site, Chengjiang. Interestingly, only 8% of the species found at both sites are the same, which proves that diversity was widespread after the Cambrian Explosion.
Sediment flows in the marine environment quickly buried the fossils, and the composition of the sediment and the environment kept the soft-tissue creatures intact.
The researchers will conduct a multitude of studies to reveal many aspects of the Qingjiang biota, Zhang said.
“The treasure trove of the Qinjiang biota provides an exciting opportunity to explore how paleoenvironmental conditions influenced ecological structuring and evolutionary drivers during the Cambrian Explosion,” said Allison Daley in a perspective that accompanied the study. Daley, who was not part of the study, is a paleontologist at the University of Lausanne in Switzerland.
