Proto-Indo-European is a reconstructed language, meaning, it is what linguists concluded a parent language of Sanskrit, Latin and Greek would have to be like.
Because most existing species live in Australia, early researchers concluded that Varanus originated in Australia and subsequently island hopped westward along the Indo-Australian archipelago.
Perhaps the most striking sign of mobility is the fact that by the third millennium B.C., most pastoralists in this huge region spoke related languages ancestral to the modern Indo-European languages.