South African fossils reveal the lost world of ancient invertebrates

The discovery of fossilized invertebrates at the site, including what could be the earliest body of a leech, is revealing the hidden diversity of the Permian period, while other fossils from the quarry have helped to solve a long running botanical mystery.

When it comes to fossils, it's normally the big animals that get the most attention. But a site in South Africa is showing that small finds can be impressive too.

Though they remain to be described in detail, the fossils found at the newly revealed site, known as Onder Karoo, appear to set a number of firsts. They include what may be the earliest-known freshwater leech, and exquisitely preserved water mites—pushing back the confirmed occurrence of this group of arachnids by 150 million years.

Together, these fossils help to fill in the gaps around the we know existed in the past, and create a picture of what they would have seen and experienced.

Dr. Rosemary Prevec, who has led a new paper detailing discoveries at the site, says, "The fossils we are finding are very ancient but are beautifully preserved. This includes very fine details like the hairs and veins of insect wings, the gut contents of insects, and soft animals and plants which aren't often preserved well."

"Together, the site provides a close-up and detailed look at an ancient ecosystem, rather like holding up a magnifying glass to one small part of the world as it was many millions of years ago."

The Karoo Basin is a rich source of fossils for the Permian Period of life. Credit: WOLF AVNI/Shutterstock

Onder Karoo has revealed Glossopteris fossils (a) and invertebrates (b). Credit: R. Prevec, licensed under CC BY 4.0 via Communications Biology

Before excavations at Onder Karoo, Glossopteris was mostly known from fragmentary leaves. Credit: Daderot, licensed under Public Domain via Wikimedia Commons