Weder Fortpflanzungsschranken, noch genetische "Abstände" noch anatomische Taxonomien führen nach Auffassung von Pääbo (Neanderthal Man - In Search of Lost Genomes) zu akzeptabelen Abgrenzungen von Spezien oder Arten in der menschlichen Evolution.
Wenn von HSN, HSS, Denisova etc. die Rede ist, sind das seiner Auffassung nach eher arbeitstechnische Beschreibungen, um bestimmte Populationen in bestimmten Gebieten zu bestimmten Zeiträumen zu beschreiben. Über Artabgrenzung zu diskutieren, ist demnach form-, frist- und fruchtlos und führt zu keinen Ergebnissen außer akademischen Turnübungen oder plakativen Benennungen für abgegrenzte Populationen in Publikationen.
Zitat reiche ich nach.*
*EDIT:
"However, I felt vaguely uneasy about suggesting a new species and soon had second thoughts. To me, taxonomy, the classification of living organisms into species, genera, orders, and so on, is a sterile academic exercise, particularly when discussing extinct human forms. ... Another reason I dislike taxonomy is that it has a tendency to elicit scientific debates that have no resolution. For example, if researchers refer to Neanderthals as “Homo neanderthalensis,” they indicate that they regard them as a separate species, distinct from “Homo sapiens.” This invariably infuriates multiregionalists, who see continuity from Neanderthals to present-day Europeans. If researchers say, “Homo sapiens neanderthalensis,” they indicate that they see them as a subspecies, on par with “Homo sapiens sapiens.” This invariably infuriates proponents of the strict out-of-Africa hypothesis. These arguments I prefer to avoid, and although we had by now shown (but not yet published) that there had been mixing between Neanderthals and modern humans, I knew that taxonomic wars over Neanderthal classification would continue, since there is no definition of a species perfectly describing the case. Many would say that a species is a group of organisms that can produce fertile offspring with each other and cannot do so with members of other groups. From that perspective we had shown that Neanderthals and modern humans were the same species. However, this concept has its limitations. ...
We didn’t know whether the fact that Neanderthals contributed perhaps 2 to 4 percent of the genes of many present-day humans meant that they were the same or different species. So it was ironic that, having always refrained from using a Latin name for Neanderthals in* our papers, I was now on the verge of introducing a new Linnaean species designation myself.
Despite my misgivings about fruitless taxonomic debates, I felt I had some reasons for this digression from my principles. The mtDNA of the Denisova individual was about twice as different from the mtDNAs of modern humans as was the mtDNA of Neanderthals. That probably made them more like H. heidelbergensis, who did get to have their own Latin species name. But there was also vanity involved. Not many people get to name a new hominin species, which made it tempting to do so, even more so because this was the first time it would be done based solely on DNA data. However, the deciding argument came both from some people in our group and from Henry Gee at Nature. He pointed out that if we didn’t take the initiative and give this hominin group a species name, someone else would. And that person might come up with a name we didn’t like. So, after deliberating with Anatoly and the team who had excavated the crucial finger bone, we settled on provisionally naming it Homo altaiensis."
