It is nearly certain that the Reptilians are not in fact from the star system of Alpha Draconis, but of terrestrial origin. One theory is that they are a higher caste of Zombie, where the zombification process has left a residual lizard brain. Another is that they are a next evolutionary stage of the ancestral population, and that they have just found it convenient to make use of the Zombie hoards in order to supplant it.
Christopher Lasch, in 1994: THE REVOLT OF THE ELITES.
Angelo Codevilla describes them, from 2010, America’s Ruling Class.
Another take on the emergent caste system by Michael Lind: The New Class War.