I think "Human brain evolved from two separate organs" would've been more accurate and sufficiently simple/short for a headline, but I guess it won't fly either due to political reasons.

Lying is always a bad choice. The paper in Nature says

"Hence, we postulate the brain is a composite organ emanating from two lineage-restricted progenitors; these dual progenitors may be evolutionarily conserved across 550 million years from hemichordates to mammals."