If you take the time to actually read the article you find that out of ~1,040,000 species previously named, 300,000 are definitely distinct species. ~480,000 are pseudonyms for those, and another ~260,000 are as of yet undetermined as to their status as distinct species. Since those others are undetermined, it cannot be said with any certainty that they are not distinct species. It would be just as (un)truthful and (in)correct to lump those in with the 300,000 known species and call it more than half.
Shoddy work on the part of the reporter.