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Neanderthals, Denisovans and our species (Homo sapiens) are commonly cited as closely related subspecies, even interbreeding with each other. Yet our species theoretically didn't migrate out of Africa until about 60,000 years ago, whereas Neanderthals were living in Europe a few hundred thousand years ago. Did they evolve out of Homo habilis, which migrated out of Africa before our species?

This suggests that Neanderthals must have evolved from Homo sapiens (or perhaps Homo habilis) stock in Africa before migrating out of Africa to Europe. However, conventional wisdom suggests that Neanderthal morphology was shaped by Ice Age Europe.

One possibility is that they evolved into a distinct subspecies in Africa, then migrated into Europe, where continuing evolution turned them into the familiar Neanderthals. But wouldn't this mean that Homo sapiens (the ancestor of Neanderthals) then migrated out of Africa hundreds of thousands of years ago?

Is this simply a question that hasn't been resolved, or is there a popular theory that explains the origin of Neanderthals and Denisovans?

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    $\begingroup$ You are calling Homo sapiens both 1) the current homo lineage and 2) the ancestor of Homo sapien and Homo neanderthalis, which make it a little hard to understand (you might want to have a look at this post). It gets even more confusing that most people call both neanderthals and modern humans as Homo sapiens (H. sapiens sapiens and H. sapiens neanderthalis). $\endgroup$ – Remi.b Feb 17 at 19:26
  • $\begingroup$ You just made my point. The precise classification and relationship between Homo sapiens and H. neandertalensis isn't really known. So where did Neanderthals come from? Did they evolve in Africa or Europe, and from WHAT did they evolve? Homo habilis? That's what I asked. $\endgroup$ – David Blomstrom Feb 17 at 19:53
  • $\begingroup$ Are you asking whether we have a name for the MRCA of sapiens and neanderthals? $\endgroup$ – Remi.b Feb 17 at 19:56
  • $\begingroup$ Yes, knowing the MRCA would be helpful. If Neanderthals evolved in Europe, and Homo sapiens didn't enter Europe until less than 60,000 years ago, then Neanderthals must have evolved from Homo habilis or some other ancient human. $\endgroup$ – David Blomstrom Feb 17 at 20:53
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The topic is reviewed in a freely available Nature article, from which the figure below (I have added the labels ‘Hominid’ and ‘Human’) is taken. As can be seen it is thought that the lines leading to the ancestor of Neanderthals/Denisovans and that leading to modern humans diverged before humans had left Africa; and that the lines leading to Neanderthals and Denisovans split from their common ancestor subsequently.

You will notice that the article refers to “modern humans”, rather than Homo sapiens, presumably because this terminology is confusing, whereas the picture is clear.

Hominid evolutionary tree

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  • $\begingroup$ I noticed this morning that my labelling of the picture was confusing and have altered it. Likewise the text. Apologies. (Presumably those who voted for it were voting for the diagram, which tells the story itself.) $\endgroup$ – David Feb 18 at 8:15
  • $\begingroup$ "However, other hominins, such as Neanderthals, which disappeared from the fossil record about 40 kyr ago11 (Fig. 2), have been found throughout Eurasia as far back as 400 kyr." - This isn't really made clear in the picture. The "Out of Africa" there means just modern humans. $\endgroup$ – JollyJoker Feb 18 at 9:23
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    $\begingroup$ @JollyJoker The way I read the picture is that branches are genotype and geographic branches. I.e. Nendethals migrated to Europe and Asia, Denisovans migrated east into Asia and Oceania, but were not present in Africa. That is, you are right that the "Out of Africa" label refers to modern man, but the branches depict all migration. $\endgroup$ – Peter - Reinstate Monica Feb 18 at 12:59
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I think your whole issue is more a problem of semantic than phylogenetic.

You are asking for the name of the ancestor of Homo neanderthalis (aka. H. sapiens neanderthalis) and H. sapiens (aka. H. sapiens sapiens). You are asking whether H. sapiens is the ancestor in the sense that H. sapiens would not be monophyletic or whether maybe H. habilis could be the ancestor.

In general, any fossil we found (species are described after found fossils) are never a direct ancestor of a current lineage but always some kind of an offshoot. The reason is probabilistic. Go back long enough in time and the vast majority of individuals that lived at that moment did not live any offspring today (see coalescent theory for more info). As a consequence, the MRCA are typically not named.

So, one can talk about the phylogenetic relationships among species, one can talk about when did what substitution happen but calling one species as the descendent of another is mainly non-sense (simply because ancestors are not named).

These semantic difficulties with the concept of species are very common, even sometimes among trained evolutionary biologists. You might want to have a look at the post How could humans have interbred with Neanderthals if we're a different species? that talks about these difficulties.

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