Well there's two reasons for that: skin tone from natural tanning ability, and skin tone from inheritance.

A lot of Latinos are actually Blatinos or Latalians... mixed with Black, Italian, White... whatever. So the lighter and darker skin complexions are from mixed backgrounds.

The other type deals with geographic location. American Latinos living in the Midwest (like myself) look very caucasian, compared with Cuban Latinos living in Miami, or Mexican Latinos in Southern Cali.

But I don't agree with the few sites that promote Latinos, yet when you look at the models, they may as well be 100% pure black except for the Puerto Rican flag wrapped on their head as a bandana. I think those deeply dark Latinos, who even sport the little curly black-type pubic hairs, should be on AA websites when it comes to promotion. If I were promoted as a Latino, I would probably fit in an Italian/European site because I don't look very Hispanic at times.