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Most the skulls trying to say this are carbon dated and separated by MILLIONS of years apart!
The fossils are not carbon dated because radiocarbon dating is not generally accurate beyond 50,000 years and not at all accurate beyond 100,000 years due to having so few atoms of leftover C14. Generally, such fossils are dated by their placement in the geologic record which is dated using various argon isotopes and paleomagnetism in associated volcanic deposits that must have occurred at roughly the same time according to basic geologic principles such as superposition.
What about within these MILLIONS of years? They are TOO far apart to connect. Who is to say they weren't just a new and died out species?
The various fossils associated with the human lineage over the last 5 million years are not themselves separated by millions of years but rather orders of tens to hundreds of thousands. In fact in several instances different species actually overlap in time as shown
here.
This particular thread is not the place to discuss human evolution so further exploration of the topic may either be in other preexisting threads or perhaps one of your own invention. I would direct you to the proper area myself but have not kept up with every post here recently. Perhaps others could help in this matter.
Read not to contradict and confute, not to believe and take for granted, not to find talk and discourse, but to weigh and consider - Francis Bacon
The more we understand particular things, the more we understand God - Spinoza