Surprising discovery: chitin preserved in trilobite fossils over 500 million years old

A close-up of a preserved Trilobite fossil. Credit: University of Texas at San Antonio

doi.org/10.2110/palo.2024.025
Credibility: 989
#Trilobite

Scientists have just made a fascinating discovery that changes our understanding of the preservation of biological molecules over geological time

In trilobite fossils-those famous marine animals with segmented bodies and an almost alien appearance-over 500 million years old, clear chemical evidence of the presence of chitin was found.

Chitin is a resistant organic material, the same one that forms the hard shells of crabs, shrimp, and lobsters today, as well as the exoskeleton of insects.

It is the second most abundant natural polymer on the planet, second only to cellulose in plants.

Until now, no one had definitively confirmed the presence of this compound in trilobites, despite them being distant relatives of modern arthropods.

The research, conducted by an international team led by Elizabeth Bailey of the University of Texas at San Antonio, analyzed fossils from the Carrara Formation in western North America, dating from the Cambrian period-a time when life exploded in diversity in the oceans, about 500 to 541 million years ago.

Using advanced and sensitive chemical techniques, the researchers detected preserved chitin in these fossils, which are normally seen only as mineral structures.

This preservation is surprising because, for a long time, it was believed that complex organic molecules like chitin degraded rapidly after the organism’s death due to the action of microbes and chemical processes.

However, under special burial conditions, some biological compounds manage to survive for hundreds of millions of years.

The discovery goes beyond paleontology.

It shows that molecules important for life can last much longer than we imagined in the geological record.

This has interesting implications for understanding the carbon cycle on Earth over geological time.

Since chitin is present in limestones formed from biological remains, it contributes to carbon storage over extensive geological periods-a natural carbon sequestration process that helps regulate CO2 levels on the planet.

Elizabeth Bailey highlighted that when we talk about carbon sequestration, people usually think of trees and forests.

But chitin, being so abundant, also plays an important role.

Proving that it can persist for so long reinforces the idea that limestones, rich in biological material, are key pieces in the carbon balance and the Earth’s climate in the long term.

This discovery, published in the journal PALAIOS, opens new perspectives for future research on how ancient organic matter is preserved and what this reveals about the early evolution of life and the functioning of our planet over billions of years.

Published in 02/18/2026 02h57

Portuguese version

Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.

Reference article:

Original study:

{teste}