Complex sentence: In the Miocene, the fossil record suggests many animals suited for forest or woodland were replaced by grazers suited for living in grasslands, so evidently much of North America and Asia became dominated by savanna.
Split into simpler sentences: In the Miocene, the fossil record suggests that many animals suited for living in forest or woodland were replaced by grazers suited for grassland. This suggests that much of North America and Asia became dominated by savanna.