Okay....that's one. How many gazillions to go? I'll learn at the pace you find more species jumps that occurred natually.
You got a lot of finding to do. On you mark, get set,.......
The all occurred naturally, one mutation at a time.
I have already shown that your idea that all mutations are fatal is incorrect. Now all you have to realize is that mutations occur all the time, most are neutral, some benficial, and some fatal. Add lots of individuals in a population and lots of time and you often get species-level changes. Not jumps, but changes over time.
Google "ring species" for one example of this kind of change. This may be easier for you to visualize.