My final word.
You claim that living speciation should be 100% morphologically determined. If this was the case poodles and dalmations would be classified as different species due to their morphological differences. Therefore by your definition of morphology speciation has already been observed occuring.
In reality species are a man made grouping in an attempt to divide up organisms on earth into distinct groups. But in nature there really are no distinct groups. There will always be animals that cross any lines you come up with. Ring species are an excellent example of this. Mutations can cause two populations to be no longer capable of interbreeding. Further mutations can diverge the morphology of those populations. There is no known barrier on how far this change can go, and it is entirely likely that it goes as far as explaining the documented changes in the fossil record.
That hypothesis gets tested all the time. And it never fails:
All present and fossilized animals found should conform to the standard evolutionary tree. And they do.
Fossilized intermediates should appear in the "correct" chronological order on the standard tree.
Species that are more closely related should share a greater portion of their DNA..