The teeth in the lower jaw are in remarkably good shape.
They really are. A complete set of molars is present. Looking at the lower jaw, it's pretty apparent that this is some sort of monkey or ape, not anything else. The period is especially interesting for researchers working on the common ancestry concept, and this looks like a very rich source of fossil material. It's rare to find stuff in such good preservation, and that's going to play a large part in this.