New species do not simply pop into existence and then replace their precursors, but rather speciation is a gradual process that serves to cause new types of creatures to slowly branch out rather than necessarily replace the original population. It does not necessarily mean the original species dies out and does not always even mean that the two species will be in direct competition with each other as one could have broken away from the “parent” population in order to exploit different resources. This is one reason the speciation may have occurred to begin with as different isolated populations could have developed to deal with different environmental challenges and been subject to different selective pressures. The idea of two species of early humans existing side by side, even ones that evolved from another, is not unfeasible in the least.

The European Neandertals picked up the culture of the first H.s.s’ to come into Europe, that, along with the occasional evidence of interbreeding suggests that there was communication and at least trade relationships. Stories might have gotten passed back and forth along with the other cultural items.

firstly, it has been accepted for decades that various hominid species co-existed for long periods of time in the past. This is no kind of ‘breaking news’ for archaeologists and palaeoanthropologists.

secondly, this is more or less completely irrelevant to the question of whether or not we presently share to planet with other hominid species. We know woolly mammoths existed contemporaneously with african and asian elephants but that fact has no bearing on whether woolly mammoths presently exist.

thirdly, this has absolutely no bearing on the truth of evolutionary theory, despite what shumway desperately wants to believe.

fourthly, the fact that members of the species homo habilis and homo erectus may have coexisted doesn’t invalidate the theory that the one evolved from the other- when new species emerge they do not necessarily do so in such a way that the species they evolved from disappears. Speciation typically occurs when a sub-population of one species becomes genetically isolated (by some mechanism) from other populations. Genetic changes then spread within this limited sub-population, that are not present in the wider population- the two populations thereby come to diverge, but it is not the case that the ‘parent’ population ceases to exist. They might become extinct, but just as likely they will continue on their own evolutionary trajectory. It is entirely possible for a sub-population of Homo habilis to evolve into Homo erectus, while a wider population of Homo habilis continues to exist.
Whether, in fact, this is what happened is a another question, but the fact of the two species co-existing is not incompatable either with the present evolutionary scenario, or with the coherence of neo-darwinian natural selection as an evolutionary mechanism.

In the “Tale of the bones” diagram shown, some anthropologists would switch the places of Homo erectus and H. ergaster.