“unknown prehistoric world” sounds like a major discovery. If the title of the article would have been “stromatolites discovered in remote lagoon from 1 billion years ago” it would not have implied that some new “world” was discovered. If by world we just mean unknown habitats, well voila, everywhere you look there will be unknown prehistoric worlds. Find a fossil of some super known, cosmopolitan species but in a new place, voila, new world yet unknown to men discovered. Idiotic.
Dude, while stromatolites are not common today, they are not unheard of. There are still some active ones in Australia, Peru and the Bahamas. Every single thing on this planet can trace a direct line from the first live when it evolved. Thus, everything on this planet has the same age. Even if a fossil could suggest that some organism has not changed much for millions of years, we can not look at the cells and their genetic makeup to infer if other significant changes have occurred not reflected by the fossil remains.