I tried to Share with you the information about Mentawai Island. If you have an others information and need to post into this blog, you can contact me at gustishell@gmail.com.
When ice age, around one million until ten thousand years ago, the surface of sea in Shouteast Asian 200 meter lower from now. Sumatera can be with Java, Kalimantan, and Asian Continent. It couses the free change between animals, and also the similar between flora-fauna from the three islands. But Mentawai Islands still eliminated from Sumatera by sea around 1500 M since Middle Pleistocene era (data of bathymetric).
One possible of Pleistocene beside the north. But if this relationship is there, this condition will be gone since before.
Mentawai Islands is original islands since five thousands years ago, flora and fauna was safe from the dynamic evolution changing like in other small Sunda.