Fossil was found in rock strata 330 million years old.
In non-scientific articles about science you're not going to get a 10 page long description of how every date in the article was arrived at citing every source and technique used, just as in every newspaper article about some criminal convicted with DNA you're not going to get a 10 page long blow-by-blow description of how the DNA test was done.
A simple mention of the type of dating would have been sufficient.