Metazoans now 600 million years old

This just in: Martin Brasier and Duncan McIlroy have published a paper in the _Journal of the Geological_ Society of London_, 'Neonereites uniserialis from c. 600Ma old rocks in western Scotland and the emergence of animals.' This documents apparent metazoan trace fossils from rocks about 50 million years older than the oldest previous metazoan trace fossils. (That is, than the oldest unambiguous metazoan trace fossils

Cool. My first question is: What are the error bars onthe date for the 'c. 600 Ma old rocks'?

The 'pedal' traces are more convincing than the purported fecal blobs. But I'll buy their evidence (once I read the paper).

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I believe molecular evidence suggests a date around 1 GYr. I also suspect the Cambrian explosion reflects the end of global glaciation ('ice ball' conditions), with most of the ocean column being previously