The okapi is another case, there were many myths of creatures made up of parts of other more well known animals living in jungles of Africa, after some .... based on the extreme unlikelihood that such creatures could elude detection or capture in modern times, but it's difficult to prove with certainty that they don't exist. read more
If anything the process tends to move in the other direction- in ancient times there were mythical creatures associated with places like India, and even five hundred years ago the same ones were thought by some to exist in the New World. read more