At http://phys.org/print301582052.html … is about the search for a common ancestor linking modern humans with Neanderthals. Going by dental fossils (they don't have much else to play with) none of the suspects (so far) fit the assumed profile – of an ancestor of both Neanderthal and modern humans, on the basis, it is thought, the two lines diverged around one million years ago.
Perhaps the assumed profile is what is wrong? The assumption we are all descended from a group of people that came out of Africa during the last Ice Age (or possibly during the last Interglacial) is the consensus theory that is continuously requiring the prop up technique. The evidence doesn't necessarily fit the theory – but you wouldn't think that going by the literature (or what is disseminated by the erstwhile academics). Around 40,000 years ago, during some kind of event which caused a C14 plateau, Neanderthals disappeared and in their place there were modern humans. At the same point in time there were big changes in the animal kingdom as well – which is rarely connected. Anthropologists do not habitually read the work of Palaeontologists. Even if they do, out of curiosity, it doesn't appear to enter into anthropological arithmetic. Might the fossil record be telling us something?
The study is published by PNAS and is basically saying that no known hominin species matches the expected dental morphology of the last common ancestor. It is assumed they had a common ancestor – but did they. It is also assumed Neanderthals died out and were replaced by migrants from outside Europe and western Asia. What they are also saying is that modern humans and Neanderthals are not related to Homo erectus or others such as Home heidelbergensis etc. Yet, the latter, via Denisovans, have a connection with modern humans in Austronesia, and Neanderthals weren't too different from modern Europeans. It sounds like an artifact of the late Victorian era when non-moderns were considered to be grunts. That was the theory, the basic nuts and bolts of the gradualist theory, from primitive hominin, to a developed hominin, and lastly to the modern human, the superior version as produced by evolutionary development. Humans are thought to have developed out of grunts – and Homo erectus are grunt grunts, grunting more that Neanderthals, yet there is ambiguous evidence which would suggest they were not quite such grunts after all.
The problem they have of course, rarely admitted, is that the assumption that modern humans developed in Africa suffers from precious little evidence, doe or against. The African fossil record from the period of interest is simply absent – or almost absent. The whole caboodle is based on speculation rather than fact.