Check out how the dark skinned Mexicans are treated by their light skinned brothers...
I spent a lot of time in Honduras, and the "indigenous" looking Hondurans were treated like dirt. The casual racism against them was appalling. The darker the Honduran, the lower social standing except the Africans. Those had come over on a pair boats back a few hundred years ago and they aren't lumped in with the "natives".
It reminded me of that Star Trek episode "Let that be your last battlefield" where half the people were dark on one side and white on the other and the other half of the people were opposite. Hondurans would indicate "avoid that guy, he's a lowlife" and just like Kirk, I couldn't see why, they looked the same to me.
dark-skinned vs light-skinned Mexicans ...
If you really want to hear some nastiness, check out how light-skinned Mexicans treat south Americans like people from Guatemala or Honduras.
Not pretty.