One of the toughest predators on earth 500 million years ago would have remained unknown to us were it not for the remarkable process of fossilisation. It is surprising that fossils form at all because of its complexity, according to a specialist in fossils.
Prof Derek Briggs, professor of palaeontology at the University of Bristol, last night discussed the unusual processes which allow soft-bodied creatures that lived millions of years ago to be preserved in the fossil record.
Prof Briggs, originally from Dublin, won the 2001 Boyle Medal for scientific excellence, an award jointly presented by the Royal Dublin Society and The Irish Times and last night delivered his Boyle Laureate lecture. The lively presentation, "Fantastic Fossils", described his work in understanding the complex natural processes that allow fossils of ancient soft-bodied creatures to form.
He talked about the metre-long Anomalocaris, the largest predator of its day 500 million years ago. The animal was discovered in the Burgess Shale deposits in Canada, one of the world's greatest repositories of the explosion of species that emerged during the "Cambrian Radiation".
All of this rich tapestry of life would have remained unknown to us were it not for soft-body fossilisation processes. "There were in effect no shells, no hard parts had evolved," Prof Briggs said. He worked on the Shale while a Ph.D student at Cambridge.
Anomalocaris "was the biggest predator in the Burgess Shale fauna", he explained. "This particular animal didn't have any mineralised tissues in life. Without the Burgess Shale it would simply not be known."
Bone and shell fossilised readily but the preservation of soft tissues required "special conditions", he said. He and his research group had been able to duplicate these complex, bacteria-driven processes.
It was also a remarkably quick process, he said. His work in the lab had shown that given the correct conditions the processes that allow preservation and fossilisation began almost immediately and were well under way "within a matter of weeks".
