That previous fossil-finder (Abigail Allwood) wrote the overview article (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19429.html http://www.na

That previous fossil-finder (Abigail Allwood) wrote the overview article (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19429.html http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...) introducing the Nature paper that is the subject of the OP. Her overview emphasizes the significance of this finding for exo-life, linking the finding to recent discoveries of ancient water, lakes, and streamflows on Mars, rather than the caveats. The more general news-based article in Nature (http://www.nature.com/news/claims-of-earth-s-oldest-fossils-tantalize-researchers-1.20506 http://www.nature.com/news/claims-of-earth-s-oldest-fossils-...) has several experts checking in with caveats.