The human race, as homo sapiens has not existed for 4 million years. And during that time period there was more than one species of homo and though we can't tell for sure some of them probably could not interbreed.
Animals go extinct too and we are the only line that survived.
With the thousands of years of (supposed)continental separation of humanoid species, there surely should have been differences in physical abilities and biological differences that your "circle species" argument infers.
I have yet to see you produce an example of that as the case ...therefore that argument is BS as it is presented.
Your argument concerning earlier species is purely hypothetical also...as you have NO tangible proof that any of it is valid and actuality.
Show us any skeletal and genetic matches for any humanoid mutation that can in any way "prove" the evolution of the humanoid line as it is proposed, and the reasons for the occurrences of change and/or mutation.
The earliest known ancestor of man was 4.4 million years ago...so don't hand me that BS either.