The Lophoraptoridae are a family of dragons which can be found only in south america. Before the continent connected with north america, they are the dominant predators, but Smilodon was not the only emigrant from the north. Species like Uxuldraco [link]
crossed Panama and conquer the new habitats. After that event, some of the Lophoraptors extinct. Only the smaller, lighter breeds survive the ice ages.
When the human race reach the continet, some of the emigrant species are extinct too.
Daulophoraptor is the only species that dosen't live in the Andes. They hunting snakes, Maras and big birds.