Microbiotheria
The study also confirmed that the most basal of all marsupial orders are the other two South American lineages (Didelphimorphia and Paucituberculata, with the former probably branching first). This indicates that Australidelphia arose in South America (with the ancestors of all other living marsupials), and probably reached Australia in a single dispersal event after Microbiotheria split off (originated).