11. The region was once on the southern coast of the ancient supercontinent of Laurasia . 12. The rodent fossil record dates back to the Paleocene on the supercontinent of Laurasia . 13. Later, they separated into Gondwana and Laurasia . 14. The Carboniferous was a time of active South China continents were still separated from Laurasia . 15. This margin existed until Laurasia and Gondwana collided in the Waco Austin San Antonio trend. 16. Fossil taxa are known from throughout Laurasia . 17. Proto-Laurasia and Proto-Gondwana were separated by the Proto-Tethys Ocean. 18. The clockwise motion of Laurasia led much later to the closing of the Tethys Ocean. 19. The Litopterna occupied ecological roles as browsers and grazers similar to horses and camels in Laurasia . 20. The predominant theory suggests that rodents first evolved in Laurasia , and expanded outward from there.
