"Until recently, dromaeosaurs had been found only in Asia and North America and only in the Cretaceous period, which ran from 145 million to 65 million years ago. Evidence that they existed in the Southern Hemisphere has been mounting.
"Since dromaeosaurs had only been found in places that used to be part of Laurasia, scientists figured the beasts evolved into being after Pangea split.
"But the Buitreraptor fossil in South America, which dates back 90 million years and closely resembles fossils from the North, means one of two things:
"Either dromaeosaurs existed when Pangea was intact;
or the newfound Buitreraptor and its northern look-alikes evolved separately yet with remarkably similar results."
http://news.yahoo.com/s/space/20051012/sc_space/newfounddinosaurforcesrethinkonemergenceofraptors