Oldest Pre-Cambrian Organism Discovered

There's a new article over on DigitalJournal.com called "Oldest Pre-Cambrian organism with skeleton found in Australia" that discusses a 550 million year old skeletal fossil that sets a new beginning point for such organisms.  While you might not want to detail your tabletop roleplaying setting all the way back to that time, it does give some food for thought as to just how old a setting can be.  Plus, if you are including time travel, the implications of what might happen if things go wrong are rather severe.  Read more here!