Scientists have discovered the world's oldest known cholesterol in a 380-million-year-old crab-like fossil in Australia.
Researchers found sterols, including cholesterol, coexisting with their fossilised counterparts (geomolecules) in the creature from the Western Kimberley - a discovery previously assumed unfeasible.
The study by Curtin University demonstrates sterols can be preserved for longer through an exceptional preservation process, providing the oldest and most extensive molecular relics of the Devonian age.
"The exceptional preservation of the crab-like fossil, which has extended the occurrence of sterols by 250 million years, is a consequence of early microbial encapsulation preventing full decomposition in the Devonian seas," researchers Ines Melendez of the WA Organic and Isotope Geochemistry Centre (WA-OIGC) at Curtin, said.
Melendez said the coexistence of more than 70 steroids in one sample confirmed a proposed scheme for the transformation of biomolecules into geomolecules (the fossilised version).
"However, we now know this was a microbially induced process rather than thermally driven one as previously assumed," said Melendez, who led the study alongside visiting Professor Lorenz Schwark from Christian Albrechts University, Kiel, Germany.
Melendez's supervisor Professor Kliti Grice, Director of WA-OIGC, said their research demonstrates concretions within rocks were able to preserve biomolecules and geomolecules at remarkable levels.
"This opens up a novel window of opportunity to study such components in very ancient samples and improves our understanding of microbial evolution and past environmental conditions," Grice said.
The study was published in the journal Nature Scientific Reports.
