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
South China (continent) Ocean. By the Late Carboniferous (300 million years ago), while North China collided with Siberia and Kazakhstania, completely closing the Proto-Tethys Ocean, South China became an independent continent. For much of the Permian Period, South China remained in the tropical latitudes. And also, while most of the giant lycopods of the Carboniferous disappeared, giant lycopods remained in South China, since its isolation from the now formed Pangaea. Cimmeria, a microcontinent that consisted of today's Tibet, Iran, Turkey, and parts of Southeast Asia rifted away from Gondwana (just as North and South China did earlier), and was heading towards Laurasia. Paleo-Tethys