In Star Trek Enterprise a body from the future had DNA fragments from something like a dozen different "species". Vulcans, Klingon, and Human were all included.
The thing about life boundries though in biology is that the more you know the less it makes sense. All bacteria are technically a single species, as are Archaea. Virus's aren't considered alive at all, though they do evolve. Then there are asexual creatures entirely. I vaguely recall a lizard that has no real genetic diversity because they are all females that reproduce without any sex, and there are no males. So... they're not a species either, but are still reproducing. Biology is screwy.