Martin Brasier of Oxford University jokingly referred to the ‘MOFAOTYOF Principle’ in his talk – the ‘My Oldest Fossils Are Older Than Your Oldest Fossils’ phenomenon. He makes fun of it (such competitions can perhaps get a bit silly), but it is the business that Brasier and his team are in – hunting down those oldest fossils of the old.
Certainly you can’t get older than the Ediacaran when it comes to animal fossils, and this was the subject of Brasier’s talk – the strange squished creatures preserved in the rocks of Mistaken Point, Newfoundland. At the end of his talk, Brasier threw up a slide showing some ‘trace fossils’ – the fossilized tracks that some worm-like or snail-like creature left behind. Such tracks are more common in younger fossil beds, when animals were more likely to be mobile (the most commonly talked about Ediacaran beast looks like a feather stuck in the seabed, and certainly didn’t get around too much). And they’re more common in shallow waters. If such tracks are from the Ediacaran deep waters, as implied, then that would be quite exciting to those in the field. It could even push back the date of complex mobile creatures – things that move intentionally in a single direction, perhaps in search of food, with a sensory system and complex muscles – by tens of millions of years. Maybe. “A lot of people have looked at a lot of rock very hard and not seen anything like this,” I overheard Guy Norbonne, an Ediacarian expert, say over coffee. “I understand it’s under review. Let’s see the paper, and see how it stands up.”
Brasier sees a bit of a shift in how people are looking at the Ediacaran. At first there was an awed acceptance that all these squishy creatures must have been the ancestors of modern animals (so there would be a soft coral, and a squidgy early worm, etc). Then the Ediacaran creatures were seen as a ‘failed experiment’, most of which went extinct. Now there is a more sober period of working out what they all were, and which ones died out and which lived on, Brasier says. This shift is one of the reasons he wrote his recent book Darwin’s Lost World, about the Ediacaran fossils (Darwin lamented that pre-Cambrian fossils had never been found; but they have been found since, and so are not a ‘lost world’ to us).
Posted on behalf of Nicola Jones