Marsupial metatherian is "Sinodelphys szalayi", which lived in China around 125 mya. This makes it a contemporary to some early eutherian species which have been found in the same area. While placental fossils dominate in Asia, marsupial fossils occur in larger numbers in North America. The oldest metatherian fossils are found in present-day China. About 100 mya, the supercontinent Pangaea was in the process of splitting into the northern continent Laurasia and the southern continent Gondwana, with what would become China and Australia already separated by the Tethys Ocean. From there, metatherians spread westward into modern North America (still attached to
Supercontinent Neoarchean age broke off at ~2480 and and portions of them later collided to form Nuna (Northern Europe North America) (). Nuna continued to develop during the Mesoproterozoic, primarily by lateral accretion of juvenile arcs, and in Nuna collided with other land masses, forming Rodinia. Between ~825 and Rodinia broke apart. However, before completely breaking up, some fragments of Rodinia had already come together to form Gondwana (also known as Gondwanaland) by . Pangaea formed by through the collision of Gondwana, Laurasia (Laurentia and Baltica), and Siberia. The second model (Kenorland-Arctica) is based on both palaeomagnetic and geological evidence and