Oldest biological colour pigments

Extracted from shale rock beneath the Sahara Desert in the Taoudeni Basin, Mauritania – and aged at approximately 1.1 billion years old – the oldest natural biological colours discovered to date are pink, red and purple, according to a study published in the journal Proceedings of the National Academy of Sciences on 9 July 2018. The biochrome compounds – known as porphyrins – were derived from the chlorophyll molecules of fossilized ancient photosynthesizing marine creatures: tiny cyanobacteria that lived in a shallow ocean that disappeared long ago. The fossils' colouration ranges from blood red to deep purple in their concentrated form and turns bright pink when diluted.

This predates previously discovered natural pigments by more than 0.5 billion years.

This was a multi-national collaborative study between the Australian National University, Geoscience Australia (both Australia), Florida State University (USA), the Japan Agency for Marine-Earth Science and Technology (Japan) and the University of Liège (Belgium). Dr Nur Gueneli, then a doctoral scholar of Jochen Brocks at the Australian National University, discovered the molecules as part of her PhD studies.