“What is the stop button between micro and macro?”
DNA. The traits of the new species came about by some mechanism - natural selection, breeding etc. Those traits were already in the DNA of the parents. For a sea creature to evolve into a land animal, information has to be added. There is no mechanism for this to take place.
I am not saying that a new species of dogs cannot arise after small traits have accumulated over time. They can. The problem comes when you tell me that these small changes can cause a canine to change into another animal altogether.
The word species is used for classification. A new species of the genus canis is not a different animal altogether. It is a variation.
This is what creationist mean when they say animal “kind”. Zebras, horses, mules, donkeys are all variations of one kind of animal.
BTW - I like your tagline.