Scientists led by Ines Melendez from Curtin University have identified 70 intact steroidal compounds in a 380-million-year-old crustacean fossil from the Gogo Formation in the north of Western Australia.

The results demonstrate steroids 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,” explained Ines Melendez, who with colleagues reported the findings in Nature Scientific Reports.

“The coexistence of more than 70 steroids in one sample confirmed a proposed scheme for the transformation of biomolecules into geomolecules, reported in Science and Nature in 1982.”

“However, we now know this was a microbially induced process rather than thermally driven one as previously assumed.”

Co-author Prof Kliti Grice added 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.”

______

Bibliographic information: Ines Melendez et al. 2013. Exceptional preservation of Palaeozoic steroids in a diagenetic continuum. Scientific Reports 3, article number: 2768; doi: 10.1038/srep02768