A team of researchers from Northwestern University and Guizhou University, both in China and the United States, discovered and partially excavated a new treasure of marine fossils from the "Cambrian Explosion" in southern China. In their article published in the newspaper Science, the group describes what has been found so far. Allison Daley, of the University of Lausanne, published in the same issue an article from Perspective on the work of the team in China.
The Cambrian period was a period during which most ancestors of all animals began to exist – scientists believe that this has gone from about 560 million years ago to about 540 millions of years. The emergence of such a large variety of phyla in such a short time has led to the use of the term "Cambrian explosion" to describe it. Research on the period began in earnest in 1909, when scientists discovered a site known as Burgess Shale. They found fossils so well preserved that eyes and an internal body were visible. Since then, other sites have also been discovered, all in shale beds. In this new effort, researchers report the discovery of a new site near the Danshui River, which they describe as Qingjiang biota – and initial reports suggest that it could provide the best collection of Cambrian fossils to date.
Researchers have been working hard for four years in search of fossils and have discovered dozens of species, half of which had never been seen before. But the best news is that fossils are better preserved than at other sites: researchers have clear examples of soft-bodied creatures, for example, and detailed parts of the body.
The researchers noted that many things had to go well for the fossils to be so well preserved. It would have been very deep under water about 550 million years ago – at such depths, there was very little oxygen to support organisms that would have broken down the body 's bodies. Animals that have fallen to the bottom of the sea. These bodies have been covered by millions of years of sediment before conditions change and the area is pushed to become land. And in all these years, the region would have been very stable – no volcano or earthquake has disturbed the soil.
Scientists take a closer look at the first animals on Earth
Dongjing Fu et al. Qingjiang Biota – a Cambrian-type Lagerstätte fossil from the early Cambrian of southern China, Science (2019). DOI: 10.1126 / science.aau8800
Allison C. Daley. A treasure of Cambrian fossils, Science (2019). DOI: 10.1126 / science.aaw8644