The extremes found in domestic animals are rarely, if ever, found in nature. There's fairly clear lines between the gray and red wolves and the coyotes; I'm not sure how finely they would be classified by paleontologists, but it wouldn't be far off. The point I'm making is that it's somewhat arbitrary where the species lines are drawn, but that doesn't change the phylogeny deduced from the bones.
...The mechanics of such a fertilization are irrelevant. ...
Totally disagree. If they can't mate, that's it - no puppies. (Keep in mind that I'm using dogs as a stand-in for naturally-occurring animals, because human intervention has sped up their variation so much).
If Chihuahuas and Great Danes are not both canis familiaris, then show it. Otherwise, your feigned skepticism is just evo irrelevancy double-talk.
I'm not feigning anything; I'm claiming the difference in size is simply too great to allow mating.
Do you understand what a ring species is? A can breed with B, B with A and C, C with B and D, but A can't breed with D. Gulls are a classic example. Chihuahuas can breed with Jack Russells, Jack Russells with spaniels, ... hounds ... great Danes.
Gray wolves, red wolves and coyotes can all interbreed. There are no 'lines' there.
Yes, it is very arbitrary where species lines are drawn in living animals. How much more arbitrary where only fossils are available? Much.
Yep, also sympatric, allopatric and parapatric speciation.
The real question (and one that evos don't have a good anser to) is, "Why should erecting reproductive barriers to genetic variety (speciation) be considered evidence 'supporting' evolution when we all know that access to genetic variety is what helps ensure a population (or species') reproductive success and fitness?"