You have failed to answer the posit that the human species was indeed separated for many thousands of years geologically on a global scale, yet is "still" capable of interbreeding...unlike your "circle species" would suggest happening.Black Thunder's first fail was such a train wreck that I missed his second massive fail in his post.
Once again, the reason that there are no other hominids that can interbreed with man is that they went extinct. They all died off. They could not handle the pressure. Many animal species go extinct every year. Did you think that our relatives were immune to extinction?
You are making excuses for errant prediction now.