Ancient insects trapped in amber discovered in South America for the first time

Insects that lived alongside the dinosaurs have been discovered in South America.

A group of 21 different insects were found in an Ecuadorean quarry after becoming trapped in sticky tree resin 112 million years ago. This resin eventually hardened into amber, freezing the insects in time and preserving them in exquisite detail.

It’s the first time insects preserved in amber have been found in South America, and makes the region one of just a handful where similar fossils from the ancient southern supercontinent of Gondwana have been found. It reveals that the area was covered in a dense and humid forest full of conifers, ferns and invertebrate life.

Professor Xavier Delclòs, from the University of Barcelona, was the lead author of the new research. He says that finding these fossils was “an incredibly exciting moment”.

“We never expected to find such a rich deposit, with thousands of amber pieces within a layer just 70 centimetres thick. Seeing so much amber in situ was truly thrilling, and it’s much richer than any other known Cretaceous amber deposit in the northern hemisphere.”

“The amber from the Genoveva quarry in Ecuador has opened a small window into a time when global change was underway, from forests dominated by conifers to the tropical forests dominated by flowering plants that we know today.”

The findings of the study were published in the journal Communications Earth & Environment.

Where is amber found?

The oldest known amber dates to 320 million years ago, while the first containing the remains of life, or bioinclusions, appears around 100 million years later during the Triassic.

This new source of amber dates to a time in Earth’s history known as the Cretaceous Resinous Interval (CRI), a period that lasted from 125 to 72 million years ago. During this period large amber deposits suddenly start appearing in the rocks across the world from Lebanon to Canada.

So far, the vast majority of amber from the CRI formed in forests that grew in part of Laurasia, the northern supercontinent that was made up of large parts of Europe, Asia and North America. This amber is renowned for preserving all kinds of ancient life, from dinosaur feathers to parasitic fungi.

Cretaceous amber from Gondwana, however, is generally less well known. While it is found periodically in South America, none had yet been reported to contain any remnants of life.

“There are several reasons why amber with terrestrial bioinclusions hasn’t been found in South America until now,” Xavier explains. “On the one hand, it’s likely that the search for amber in this continent is not as advanced as in the northern hemisphere so it may be due to limited sampling.”

“Another possibility is that much of Gondwana was less humid, making it less likely that amber deposits would form. Finally, it’s also possible that the resin-producing trees of Cretaceous South America may have produced less resin than those in the northern hemisphere.”

The new study, however, shows that deposits have been present all along.

What was found in the South American amber?

The team studied 60 samples of amber from the Genoveva quarry, finding 21 different bioinclusions within them.

Flies were the most common insects trapped in the amber, making up more than half of the bioinclusions. One of these is thought to be a new species of Microphorites fly, an extinct group which is known exclusively from amber found all over the world.

Also among their other finds were a beetle, a springtail, a caddisfly and part of a spider’s web, as well as some parasites. The researchers found two parasitoid wasps, which lay their eggs in the bodies of other organisms, as well as a male midge from a group of blood-sucking insects.

As well as revealing what lived in the region millions of years ago, the insects found in the amber tell them something about the environment. Caddisflies, for example, have aquatic larvae, which means that there must have been pools of freshwater nearby when the amber formed.

While there weren’t any plants in the samples, fossils found in the same rocks suggest that at the time the region was dominated by forests of ferns and fern-like plants, with flowering plants and conifers growing among them. It paints a picture of a very different environment from other regions of South America at the time, which were much drier and more arid.

As more amber deposits are found in South America and other areas which used to be part of Gondwana, such as Australia and Antarctica, the team hope we’ll gain a better understanding of life in the distant past.

“Searching for new continental outcrops along the margins of ancient Gondwana, especially in more humid palaeoenvironments, should help to uncover previously unknown amber deposits,” Xavier says.

“This will give a better idea of how the region was changing as the two great southern continents, South America and Africa, began to drift apart. Studying the fauna and flora of these ancient ecosystems is essential for understanding the palaeobiogeography of many groups both living and dead.”