Well, they aren't exactly "new" fossils, now are they?
But it is good to see clearer evidence of this, this has been the main hypothesis for a while (it also explains why insects died out much more during this extinction even than others, because there was much less vegetation for them to live in/on), though it was probably some other factors as well, there's rarely ever a simple singular cause and effect when it comes to major changes to the biosphere (at least when it comes to natural extinction events)