A new fossil site of global importance discovered in the south of France

Paleontology enthusiasts have unearthed one of the richest and most diverse fossil sites in the world, dating from the Lower Ordovician period (around 470 million years ago). Located in Montagne Noire, in Hérault, this deposit of more than 400 fossils is distinguished by exceptionally well-preserved fauna.

In addition to the shell components, it contains extremely rare soft elements such as the digestive system and cuticles, in a remarkable state of preservation. Furthermore, this biota was once located very close to the South Pole, revealing the composition of the southernmost Ordovician ecosystems.

At the Faculty of Geosciences and the Environment of the University of Lausanne (UNIL), scientists collaborated with the CNRS and international teams to carry out the first analyzes of this deposit, known as the Cabrières Biota. The results are published in Ecology and evolution of nature.

Ordovician climate refuge

Analyzes of the new biota reveal the presence of arthropods (a group that includes centipedes and shrimp) and cnidarians (a group that includes jellyfish and corals), as well as large numbers of algae and sponges. The high biodiversity of the site suggests that this area served as a refuge for species that had escaped the high temperatures that then prevailed further north.

“In this period of intense global warming, animals were in fact living in high latitude refuges, escaping extreme equatorial temperatures,” explains Farid Saleh, researcher at the University of Lausanne and first author of the study.

“The distant past gives us a glimpse of our possible near future,” adds Jonathan Antcliffe, researcher at the University of Lausanne and co-author of the study.

For their part, Eric Monceret and Sylvie Monceret-Goujon, the amateurs who discovered the site, are enthusiastic. “We have been prospecting and looking for fossils since we were twenty years old,” says Eric Monceret.

“When we discovered this astonishing biota, we understood the importance of the discovery and went from astonishment to enthusiasm,” adds Sylvie Monceret-Goujon.

This first publication marks the start of a long research program involving large-scale excavations and in-depth analyzes of fossils. Using innovative methods and techniques, the aim is to reveal the internal and external anatomy of organisms, as well as to deduce their phylogenetic relationships and their lifestyles.