What is a mule?
ML/NJ
Evolution deals with breeding populations. There is no breeding population of mules.
But if you want me to admit to a mistake, I'll admit that semantically my statement is untrue.
There's an even bigger example of it being untrue. It's fairly common for plants to undergo a doubling of chromosomes. This can lead to an overnight new species.
Among successfully breeding animals, the children are always the same species as their parents. Virtually all evolution is micro-evolution.