[MikeJ]

Well, if you consider cows and bison to the same species, we'll just have to agree to disagree. I presume that a similar example, that of a potentially fertile cross between a llama and camel, would lead you to suggest that camels and llamas are the same species, too.

Many plants can crossbreed, even if they are of different genera. These are all the same species too?

Suppose I crossbreed plant A and plant B, yielding plant C. Suppose I further crossbreed plant C with other plants, yielding D, E, and F, until I finally get an example that will not crossbreed with either A or B. Is this a new species, or would we then be forced to conclude that not all members of a species can interbreed with one another?

Coffea Arabica is one such example - it cannot interbreed with either its closely related species, or with its ancestral species. Is this not a new species of plant?

[templar]

Suppose I crossbreed plant A and plant B, yielding plant C. Suppose I further crossbreed plant C with other plants, yielding D, E, and F, until I finally get an example that will not crossbreed with either A or B. Is this a new species, or would we then be forced to conclude that not all members of a species can interbreed with one another?

Well, don't just speculate about it, Do it then present the results. That way we can deal with facts in the real world, not imaginary speculation.

Coffea Arabica is one such example - it cannot interbreed with either its closely related species, or with its ancestral species.

That is because they are different, and independent, species. What is the ancestral species, and how do you demonstrate that the 'ancestral' species produced it ( a new species)? Being in the same family does not prove that one species of that family gave rise to another of that family. Again, don't just make speculative statements, demonstrate it.