You can find examples all over the web, especially in the journals devoted to the subject (which creationists refuse to read for some reason).
Here are some examples from the usual suspects.
Creationists don't accept them because a lizard is still a lizard and a fern is still a fern. But they came from one population that has split and no longer interbreeds. According to evolutionary biologists, that's how speciation begins.
The two populations may no longer interbreed, but to me the more important question is this: Are they cross-fertile, and would they produce fertile offspring?
If they have the same number of chromosomes and would produce fertile offspring, I submit to you that they are the same species.