The increasingly evident fact that there are no clear-cut quanta (isolated species), but everything, past and present, forms a continuum, is what common descent is all about.
No, because they're samples along the continuum of morphological change, and not being presented as discrete entities.
In fact, it's the anti-evolutionists who commit the fallacy of quantizing the continuum, by trying to assert that these transitionals are all "separate" creatures, and that there exist no further links between them.