Where to find Collector Items?

Is there a list that tells you where you can find certain collector items? Specifically, I'm looking for Massive Jawbones and Bleached Shells.

Thanks in advance.

I believe Massive Jawbones you can acquire from those Dune Burrowers if I'm not mistaken.
As for Bleached Shells, You can try hunting Dune wurms in the crystal desert around dunes of despair area. Not in mission area, but the exploration part.