Isolating taxon specific biomarkers from fossil bilaterians
Biomarkers are fossilised lipids that can provide unique information regarding extinct organisms. Taxon-specific-biomarkers can assist in phylogenetic reconstruction of extinct taxa, and also increase the accuracy of molecular clock calibration. Whilst there has been extensive biomarker analysis of ancient unicellular organisms, research into their metazoan counterparts is sparse. This project aims to isolate taxon-specific-biomarkers from fossil representatives of three bilaterian super-phyla: Deutrostomia, Ecdysozoa, and Lophotrochozoa. This project also attempts to decipher the depositional and diagenetic pathways for fossil and rock samples from the Lower Ordovician Emanuel Formation, Western Australia. This research revealed aliphatic and aromatic hydrocarbon profiles from bilaterian fossils using flash (curie-point) pyrolysis gas chromatography-mass spectrometry. The hydrocarbons isolated include n-alkanes (C6-C21), n-alkenes, and naphthalene and phenanthrene derivatives. Fourier-transform infrared spectroscopy analysis of fossil and rock samples detected the presence of degraded biomacromolecules. Gas chromatography-mass spectrometry analysis of rock samples enabled description of the depositional environment, overall organic matter input, and degree of thermal alteration for the Emanuel Formation. Whilst isolation of taxon-specific biomarkers remains elusive, these results show that it is possible to obtain hydrocarbon profiles from Ordovician animal fossils. Hence it is possible to obtain novel information regarding animal biochemistry otherwise not recorded in the fossil record.