Latino is not considered a separate race on the census or any government agency; it's listed as an ethnicity.
The racial categories included in the census questionnaire generally reflect a social definition of race recognized in this country and not an attempt to define race biologically, anthropologically, or genetically. In addition, it is recognized that the categories of the race item include racial and national origin or sociocultural groups. People may choose to report more than one race to indicate their racial mixture, such as “American Indian” and “White.” People who identify their origin as Hispanic, Latino, or Spanish may be of any race.
I think I can help you out a little- in the spanish and portuguese colonies, there was a distinctive racial hierarchy. At the top of this hierarchy were peninsulares, white people from the Iberian peninsula, and their children were largely held in equal regard. Below them were mulattoes, people of mixed black and white heritage. At the bottom were mestizos, which were part white and part native.