Which Viperidae subfamily is restricted geographically to the Old World (Africa, Asia, Europe) and is explicitly not native to the Americas?

Answer

Viperinae

The Viperinae, or True Vipers, are geographically restricted to Africa, Asia, and Europe, whereas the Crotalinae have successfully dispersed into both the Old World and the New World (the Americas).

Which Viperidae subfamily is restricted geographically to the Old World (Africa, Asia, Europe) and is explicitly not native to the Americas?
classificationreptilesnakeviper