Paleontologists are always shown extracting dinosaur bones from pits in dusty deserts, but most of their research occurs in libraries, and most of their discoveries are ___________ from tomes every bit as dusty as the aforementioned deserts.

The sentence displays parallelism and research in libraries with dusty tomes is compared with research involving extracting dinosaur bones from dusty pits in deserts.

We need a word that is a synonym of extracting. The word is gleaned.